Researcher Profile and Settings

Affiliation

• Research Faculty of Agriculture　Fundamental AgriScience Research　Bioscience and Chemistry

Job Title

• Associate Professor

URL

http://lab.agr.hokudai.ac.jp/botagr/pln/nabe/index.htm

Research funding number

• 60360939

J-Global ID

• 200901002122444563

Research Interests

• イオノーム   根圏   イオノミクス   重金属   イネ   有機酸   アルミニウム   微量元素   窒素固定   養分欠乏   ヒ素   可給度   重金属集積微生物   モリブデン   超集積植物   集積植物   カドミウム   ファイトレメディエーション   重金属汚染土壌   セシウム   三要素   国際情報交換（ドイツ）   ナトリウム   土壌   重金属耐性微生物   必須元素   ミヤコグサ   ICP-MS   リン   網羅的無機分析   生態・環境   植物生理学   植物栄養学・土壌学   Ecology and Environment   Plant Physiology   Plant Nutrition and Soil Science   

Research Areas

• Life sciences / Plant nutrition, soil science
• Life sciences / Ecology and environmental science
• Life sciences / Plants: molecular biology and physiology

Educational Organization

•  Bachelor's degree program　School of Agriculture
•  Master's degree program　Graduate School of Agriculture
•  Doctoral (PhD) degree program　Graduate School of Agriculture

Academic & Professional Experience

• 2012/08 - Today - 北海道大学大学院（農学研究院） 准教授
• 2003/04 - 2012/07 - 北海道大学大学院（農学研究科・農学研究院） 助手・助教
• 2002 - 2003 日本学術振興会科学技術特別研究員（国際農林水産業研究センター) 研究員
• 2002 - 2003 Researcher
• 2003 - Research Associate
• 2001 - 2002 科学技術振興事業団科学技術特別研究員（国際農林水産業研究センター） 研究員
• 2001 - 2002 Researcher

Association Memberships

• Sigma Xi   日本鉄鋼協会   日本植物生理学会   日本分析化学会   "Archives of Agronomy and Soil Science" Editorial Board   北海道土壌肥料懇話会   日本土壌肥料学会   

Research Activities

Published Papers

• Photosynthetic nitrogen utilization of Robinia pseudoacacia, an invasive species, grown in contrasting light conditions: a leaf scale approach

  Kitaoka S, Qu LY, Kanetoshi M, Watanabe Y, Fujita S, Koike T

  Annals of Applied Biology 184 (1) 61 - 71 2024/01 [Refereed][Not invited]
  
• Leaf defense traits of birch, beech, and oak saplings grown under two types of soil in a free-air ozone exposure system

  Cong Shi, Noburu Masui, Takayoshi Koike, Chisato Terada, Masahiro Nakamura, Toshihiro Watanabe

  Journal of Forest Research online first 1 - 11 1341-6979 2023/11/16 [Refereed][Not invited]
  
• Landscape gradient of autumn photosynthetic decline in Abies sachalinensis seedlings

  Tetsuto Sugai, Wataru Ishizuka, Toshihiro Watanabe

  Journal of Forestry Research 34 (1) 187 - 195 1007-662X 2023/02 [Refereed]
   

  Abstract Understanding what environmental factors are genetically linked to a phenological event is critical for predicting responses to climate change. Photosynthetic phenology often varies among a species of evergreen conifers due to local adaptation. However, few empirical studies have revealed relevant relationships between climatic factors in provenance environments and photosynthetic phenology. This study evaluated the effects of environmental conditions of the growing site and seed source provenance on the seasonal changes in maximal photochemical quantum yield of photosystem II (F_v/F_m) in a common garden experiment with 2-year-old seedlings of Sakhalin fir (Abies sachalinensis), a representative species with local adaptation, from four seed source provenances. A logistic model was constructed to explain the seasonal variation of F_v/F_m from July to October and the relationships between the estimated model parameters and representative factors featuring provenance environments were evaluated. The landscape gradient of the detected model parameters responsible for the provenance environments was visualized in a map of the distribution area. The lowest temperature was the most plausible factor in the growing environment to explain the seasonal changes of F_v/F_m. Among the representative meteorological factors of provenance environments, the lowest temperatures in July showed significant relationships with two model parameters, explaining the lower limit of F_v/F_m and the higher sensitivity of autumn F_v/F_m decline. The estimated spatial maps of model parameters consistently showed that the higher the lowest temperature in July in the provenance environment, the lower the F_v/F_m in October and the greater the decrease in the autumn F_v/F_m decline. Therefore, the lowest summer temperature could be associated with the local adaptation of autumn photosynthetic phenology in A. sachalinensis.
• Different nitrogen acquirement and utilization strategies might determine the ecological competition between ferns and angiosperms

  Chengming Zhang, Chaoqun Zhang, Takayuki Azuma, Hayato Maruyama, Takuro Shinano, Toshihiro Watanabe

  Annals of Botany 0305-7364 2023/01/20 

  Abstract Background and Aims The abundance or decline of fern populations in response to environmental change has been found to be largely dependent on specific physiological properties that distinguish ferns from angiosperms. Many studies have focused on water use efficiency and stomatal behaviours, but the effects of nutrition acquirement and utilization strategies on niche competition between ferns and flowering plants are rarely reported. Methods We collected 34 ferns and 42 angiosperms from the Botanic Garden of Hokkaido University for nitrogen (N), sulphur (S), NO3− and SO42− analysis. We then used a hydroponic system to compare the different N and S utilization strategies between ferns and angiosperms under N deficiency conditions. Key Results Ferns had a significantly higher NO3−-N concentration and NO3−-N/N ratio than angiosperms, although the total N concentration in ferns was remarkably lower than that in the angiosperms. Meanwhile, a positive correlation between N and S was found, indicating that nutrient concentration is involved in assimilation. Pteris cretica, a fern species subjected to further study, maintained a slow growth rate and lower N requirement in response to low N stress, while both the biomass and N concentration in wheat (Triticum aestivum) responded quickly to N deficiency conditions. Conclusions The different nutritional strategies employed by ferns and angiosperms depended mainly on the effects of phylogenetic and evolutionary diversity. Ferns tend to adopt an opportunistic strategy of limiting growth rate to reduce N demand and store more pooled nitrate, whereas angiosperms probably utilize N nutrition to ensure as much development as possible under low N stress. Identifying the effects of mineral nutrition on the evolutionary results of ecological competition between plant species remains a challenge.
• Potassium application reduced cesium uptake and altered strontium translocation in soybean plants

  Syaiudin, M, Suzuki, M, Maruyama, H, Kubo, K, Watanabe, T, Shinano, T

  Soil Science and Plant Nutrition 2023/01 [Refereed]
  
• Identification of a Saltol-Independent Salinity Tolerance Polymorphism in Rice Mekong Delta Landraces and Characterization of a Promising Line, Doc Phung.

  Tam Thanh Nguyen, Maria Stefanie Dwiyanti, Shuntaro Sakaguchi, Yohei Koide, Dung Viet Le, Toshihiro Watanabe, Yuji Kishima

  Rice (New York, N.Y.) 15 (1) 65 - 65 2022/12/18 

  The Mekong Delta River in Vietnam is facing salinity intrusion caused by climate change and sea-level rise that is severely affecting rice cultivation. Here, we evaluated salinity responses of 97 rice accessions (79 landraces and 18 improved accessions) from the Mekong Delta population by adding 100 mM NaCl to the nutrient solution for up to 20 days. We observed a wide distribution in salinity tolerance/sensitivity, with two major peaks across the 97 accessions when using the standard evaluation system (SES) developed by the International Rice Research Institute. SES scores revealed strong negative correlations (ranging from - 0.68 to - 0.83) with other phenotypic indices, such as shoot elongation length, root elongation length, shoot dry weight, and root dry weight. Mineral concentrations of Na+ in roots, stems, and leaves and Ca2+ in roots and stems were positively correlated with SES scores, suggesting that tolerant accessions lower their cation exchange capacity in the root cell wall. The salinity tolerance of Mekong Delta accessions was independent from the previously described salinity tolerance-related locus Saltol, which encodes an HKT1-type transporter in the salinity-tolerant cultivars Nona Bokra and Pokkali. Indeed, genome-wide association studies using SES scores and shoot dry weight ratios of the 79 accessions as traits identified a single common peak located on chromosome 1. This SNP did not form a linkage group with other nearby SNPs and mapped to the 3' untranslated region of gene LOC_Os01g32830, over 6.5 Mb away from the Saltol locus. LOC_Os01g32830 encodes chloroplast glycolate/glycerate translocator 1 (OsPLGG1), which is responsible for photorespiration and growth. SES and shoot dry weight ratios differed significantly between the two possible haplotypes at the causal SNP. Through these analyses, we characterize Doc Phung, one of the most salinity-tolerant varieties in the Mekong Delta population and a promising new genetic resource.
• Effect of Light Quality on Metabolomic, Ionomic, and Transcriptomic Profiles in Tomato Fruit

  Lingran Xiao, Tomoki Shibuya, Toshihiro Watanabe, Kazuhisa Kato, Yoshinori Kanayama

  International Journal of Molecular Sciences 23 (21) 13288 - 13288 2022/10/31 

  Light quality affects plant growth and the functional component accumulation of fruits. However, there is little knowledge of the effects of light quality based on multiomics profiles. This study combined transcriptomic, ionomic, and metabolomic analyses to elucidate the effects of light quality on metabolism and gene expression in tomato fruit. Micro-Tom plants were grown under blue or red light-emitting diode light for 16 h daily after anthesis. White fluorescent light was used as a reference. The metabolite and element concentrations and the expression of genes markedly changed in response to blue and red light. Based on the metabolomic analysis, amino acid metabolism and secondary metabolite biosynthesis were active in blue light treatment. According to transcriptomic analysis, differentially expressed genes in blue and red light treatments were enriched in the pathways of secondary metabolite biosynthesis, carbon fixation, and glycine, serine, and threonine metabolism, supporting the results of the metabolomic analysis. Ionomic analysis indicated that the element levels in fruits were more susceptible to changes in light quality than in leaves. The concentration of some ions containing Fe in fruits increased under red light compared to under blue light. The altered expression level of genes encoding metal ion-binding proteins, metal tolerance proteins, and metal transporters in response to blue and red light in the transcriptomic analysis contributes to changes in the ionomic profiles of tomato fruit.
• The ratio of plant 137Cs to exchangeable 137Cs in soil is a crucial factor in explaining the variation in 137Cs transferability from soil to plant.

  Masataka Suzuki, Tetsuya Eguchi, Kazuki Azuma, Atsushi Nakao, Katashi Kubo, Shigeto Fujimura, Muhamad Syaifudin, Hayato Maruyama, Toshihiro Watanabe, Takuro Shinano

  The Science of the total environment 857 (Pt 1) 159208 - 159208 2022/10/05 

  To mitigate radioactive cesium from soil to plant, increasing and maintaining the exchangeable potassium (ExK) level during growth is widely accepted after Tokyo Electric Company's Fukushima Dai-ichi Nuclear Plant accident in Japan. This is because the antagonistic relationship between soil solution K and 134Cs + 137Cs (RCs) concentrations changes the transfer factor (TF: designated as the ratio of radioactivity of plant organ to soil) of RCs. As the relationship between ExK and TF depends on the soil types, crop species, and other environmental factors, the required amount of ExK should be set to a safe side. Eleven years after the accident, as the activity of 134Cs was almost negligible, 137Cs became the main RCs in most of the agricultural fields in Fukushima Prefecture. We propose a new indicator, the concentration ratio of plant 137Cs to soil exchangeable 137Cs (Ex137Cs), instead of TF, which showed a better correlation with ExK even among soils with different properties (or mineralogy).
• Vigor and Health of Urban Green Resources under Elevated O₃ in Far East Asia

  Laiye Qu, Yannan Wang, Cong Shi, Xiaoke Wang, Noboru Masui, Thomas Rötzer, Toshihiro Watanabe, Takayoshi Koike

  IntechOpen (Environmental Sciences) series 2754-6713 2022/09/29 [Refereed][Not invited]
   

  Conservation of urban greens is an essential action for city residents, however, declining symptoms and/or traces in the annual ring of trees grown are found in parks and forest stands in a city as well as its suburb with a high level of ozone (O3). Urban greens, including roof-green, provide comfortable conditions for the people and a moderate environment in a city. They are exposed to severe environments; heat, drought, air-pollutions, etc. even with intensive management of the people. How can we proceed with the conservation and wise use of urban greens? We should know the ecophysiological responses of urban trees to such a global environment as well as a local one. Defensive capacities of urban greens should be analyzed in terms of damages caused by biotic and abiotic stresses, and it is important to understand their interactions from the viewpoint of plant-insect/disease. There is a concern that some green areas are suffering from an outbreak of insects and diseases, reducing the vigor and health of urban greens. We discuss these based on specific examples, such as man-made forests, in cities in far east Asia for considering our approach to how to keep urban green resources.
• Analysis of varietal differences in grain productivity and seed mineral content of oats

  Ishii Rei, Maruyama Hayato, Watanabe Toshihiro, Shinano Takuro, Kubo Katashi

  Abstracts of Meeting of the CSSJ 日本作物学会 254 12 - 12 2022/09/18
• 4-3-7 Al 耐性遺伝子PGIP1 の発現量ゲノムワイド関連解析によるPGIP1 発現を制御するシグナル伝達経路と遺伝子の同定（4-3 植物の有害元素 2022年度東京大会）

  榎本 拓央, 伊藤 弘樹, 中野 友貴, 柳瀬 笑子, 渡部 敏裕, 井内 聖, 小林 正智, 山本 義治, 小山 博之, 小林 佑理子

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 68 55 - 55 0288-5840 2022/09/05
• 4-4-4 パプリカ果実における部位別の元素動態と尻腐れ果発症との関係（4-4 植物の代謝成分と農作物の品質 2022年度東京大会）

  荒川 竜太, 鳥山 星呂, アクリッシュ 穂波, 渡部 敏裕, 信濃 卓郎, 丸山 隼人

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 68 62 - 62 0288-5840 2022/09/05
• Responses of ectomycorrhizal diversity of larch and its hybrid seedlings and saplings to elevated CO2, O3, and high nitrogen loadin

  QU, Laiye, WANG, Xiaona, MAO, Qiaozhi, AGATHOKLEOUS, Evgenios, CHOI, DongSu, TAMAI, Yutaka, WATANABE, Toshihiro, KOIKE

  Eurasian Journal of Forest Research 22 23 - 27 2022/05 [Refereed][Invited]
  
• Growth and nitrogen use characteristics of black locust, an invasive alien species, grown under different light and CO₂ conditions

  Satoshi Kitaoka, Saki Fujita, Yoko Watanabe, DongSu Choi, Toshihiro Watanabe, Takuro Shinano, Fuyuki Satoh, Takayoshi Koike

  Eurasian Journal of Forests Research 22 28 - 32 2022/04 [Refereed][Invited]
  
• Effects of soil compaction on the seedlings growth and ectomycorrhizal fungal community in hybrid larch

  SUGAI, Tetsuto, YOKOYAMA, Satoko, TAMAI, Yutaka, MORI, Hirotaka, MARCHI, Enrico, WATANABE, Toshihiro, SATOH, Fuyuki, KOIKE, Takayoshi

  Eurasian journal of forest research 22 78 - 80 2022
• Relationship between soil phosphorus dynamics and low-phosphorus responses at specific root locations of white lupine

  Ayane Kan, Hayato Maruyama, Nao Aoyama, Jun Wasaki, Yoshiko Tateishi, Toshihiro Watanabe, Takuro Shinano

  Soil Science and Plant Nutrition 0038-0768 2022 [Refereed]
   

  Phosphorus (P) is an essential element for crop production; however, availability tends to be low due to slow diffusion and high fixation in soils. To cope with phosphate deficiency, white lupines (Lupinus albus L.) form unique root structures called cluster roots. The objective of this study was to elucidate detailed spatial differences of the mechanisms under low-P condition in the root system using rhizoboxes. We cultivated plants in rhizoboxes with P-deficient soil for 33 days. We then harvested roots and the adjacent soil from 128 compartments by dividing 2 × 2 cm squares in the rhizoboxes. We investigated relative expression levels of several genes that encode proteins assumed to be involved in P solubilization or translocation. Additionally, we analyzed fractionated P, soluble metal cations (Fe, Al, and Mn), and enzyme activities in the soil of each compartment. We observed a significant positive correlation between one of the MATE (multidrug and toxic compound extrusion/detoxification) genes, LaMATE6, and soluble metal cations, suggesting the secretion of citric acid into the rhizosphere via MATE proteins increased soluble metal cation concentrations. Furthermore, we demonstrated that roots in the same developmental stages were likely to have different influences on the mobilization of fractionated P in the rhizosphere soil. Our findings highlight the importance of investigating the relationship between soil chemical properties and root functions at a high spatial resolution to elucidate the detailed mechanisms of P mobilization by plants.
• シロバナルーピンの放射性セシウム吸収と体内輸送の品種間差

  丸山 隼人, 菅 あやね, 浅枝 諭史, 久保 堅司, 古川 純, 渡部 敏裕, 信濃 卓郎

  アイソトープ・放射線研究発表会 公益社団法人 日本アイソトープ協会 2 126  2022
• Ionomic Profiling of Rice Genotypes and Identification of Varieties with Elemental Covariation Effects

  Zhang Chengming, Nobuhiro Tanaka, Maria Stefanie Dwiyanti, Matthew Shenton, Hayato Maruyama, Takuro Shinano, Chu Qingnan, Xie Jun, Toshihiro Watanabe

  Rice Science 29 (1) 76 - 88 1672-6308 2022/01
• Expression GWAS of PGIP1 Identifies STOP1-Dependent and STOP1-Independent Regulation of PGIP1 in Aluminum Stress Signaling in Arabidopsis

  Raj Kishan Agrahari, Takuo Enomoto, Hiroki Ito, Yuki Nakano, Emiko Yanase, Toshihiro Watanabe, Ayan Sadhukhan, Satoshi Iuchi, Masatomo Kobayashi, Sanjib Kumar Panda, Yoshiharu Y. Yamamoto, Hiroyuki Koyama, Yuriko Kobayashi

  Frontiers in Plant Science 12 2021/12/17 

  To elucidate the unknown regulatory mechanisms involved in aluminum (Al)-induced expression of POLYGALACTURONASE-INHIBITING PROTEIN 1 (PGIP1), which is one of the downstream genes of SENSITIVE TO PROTON RHIZOTOXICITY 1 (STOP1) regulating Al-tolerance genes, we conducted a genome-wide association analysis of gene expression levels (eGWAS) of PGIP1 in the shoots under Al stress using 83 Arabidopsis thaliana accessions. The eGWAS, conducted through a mixed linear model, revealed 17 suggestive SNPs across the genome having the association with the expression level variation in PGIP1. The GWAS-detected SNPs were directly located inside transcription factors and other genes involved in stress signaling, which were expressed in response to Al. These candidate genes carried different expression level and amino acid polymorphisms. Among them, three genes encoding NAC domain-containing protein 27 (NAC027), TRX superfamily protein, and R-R-type MYB protein were associated with the suppression of PGIP1 expression in their mutants, and accordingly, the system affected Al tolerance. We also found the involvement of Al-induced endogenous nitric oxide (NO) signaling, which induces NAC027 and R-R-type MYB genes to regulate PGIP1 expression. In this study, we provide genetic evidence that STOP1-independent NO signaling pathway and STOP1-dependent regulation in phosphoinositide (PI) signaling pathway are involved in the regulation of PGIP1 expression under Al stress.
• Nitrogen deficiency-induced molybdenum accumulation in wheat

  Toshihiro Watanabe, Ryoskuke Okada, Soyoka Tokunaga, Hayato Maruyama, Masaru Urayama, Takuro Shinano

  JOURNAL OF PLANT NUTRITION 45 (9) 1413 - 1424 0190-4167 2021/12 

  In the present study, we conducted experiments using wheat to elucidate whether the increased accumulation of molybdenum in leaves under nitrogen deficiency is due to the plant's own metabolic response, and further to estimate the role of molybdenum in the nitrogen deficiency response. Even under different growth conditions such as soil culture, hydroponic culture, and aseptic culture, the nitrogen deficiency always increased the molybdenum accumulation in leaves of wheat. Because molybdenum supply to the soil enhanced the growth of wheat under nitrogen deficiency but did not increase plant nitrogen concentration, the increased molybdenum uptake might be involved in the adaptive mechanisms to nitrogen deficiency by increasing nitrogen use efficiency. Wheat under nitrogen deficiency accumulated more molybdenum in lower leaves. Moreover, the nitrogen concentration of wheat grown under nitrogen deficiency increased in the lower leaves and decreased in the upper leaves with the application of molybdenum. These results suggest that molybdenum might affect nitrogen translocation from older to younger leaves.
• Possible solubilization of various mineral elements in the rhizosphere of Lupinus albus L.

  Atsuhide Takao, Jun Wasaki, Hisae Fujimoto, Hayato Maruyama, Takuro Shinano, Toshihiro Watanabe

  Soil Science and Plant Nutrition 1 - 8 0038-0768 2021/10/07 [Refereed]
  
• 4-1-4 シロバナルーピン根域における土壌中リン動態に与える影響の局所的評価（4-1 植物の多量栄養素 2021年度北海道大会）

  菅 あやね, 丸山 隼人, 和崎 淳, 渡部 敏裕, 信濃 卓郎

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 45 - 45 0288-5840 2021/09/03
• 8-1-11 異なる圃場におけるダイズへの放射性セシウムの移行比較（8-1 環境保全 2021年度北海道大会）

  鈴木 政崇, 藤本 久恵, 浅枝 諭史, 丸山 隼人, 久保 堅司, 藤村 恵人, 渡部 敏裕, 信濃 卓郎

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 126 - 126 0288-5840 2021/09/03
• 8-1-10 シロバナルーピンの放射性セシウム吸収特性と根圏土壌中元素動態の関係（8-1 環境保全 2021年度北海道大会）

  浅枝 諭史, 丸山 隼人, 藤本 久恵, 久保 堅司, 藤村 恵人, 渡部 敏裕, 信濃 卓郎

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 126 - 126 0288-5840 2021/09/03
• P4-1-19 トマト尻腐れ発症率の品種間差と果実への無機元素蓄積の関係（4-1 植物の多量栄養素 2021年度北海道大会）

  長谷川 公紀, 渡邊 涼太郎, 丸山 隼人, 金山 喜則, 信濃 卓郎, 渡部 敏裕

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 58 - 58 0288-5840 2021/09/03
• 4-3-8 火山性強酸性土壌に生育する植物の葉身元素組成の特徴（4-3 植物の有害元素 2021年度北海道大会）

  和崎 淳, 山本 晃弘, 丸山 隼人, 中坪 孝之, 渡部 敏裕

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 71 - 71 0288-5840 2021/09/03
• 4-1-1 ミナトカモジグサの生育および養分状態に応じたリン獲得の分子制御機構（4-1 植物の多量栄養素 2021年度北海道大会）

  永山 航平, 菅井 徹人, 佐藤 匠, 熊石 紀恵, 市橋 泰範, 渡部 敏裕, 信濃 卓郎, 丸山 隼人

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 44 - 44 0288-5840 2021/09/03
• 4-1-3 コムギコアコレクションを用いた可塑的土壌リン獲得形質の品種間差（4-1 植物の多量栄養素 2021年度北海道大会）

  青山 奈央, 渡部 敏裕, 信濃 卓郎, 丸山 隼人

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 44 - 44 0288-5840 2021/09/03
• 4-4-1 根圏の有機物・ガスに関する植物栄養学研究の一視点—根の細胞壁・細胞膜での各種の化学的・物理的な力と下流遺伝子群への注目（4-4 植物の代謝成分と農作物の品質 2021年度北海道大会）

  我妻 忠雄, 俵谷 圭太郎, 程 為国, 渡部 敏裕, 丸山 隼人, 和崎 淳

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 76 - 76 0288-5840 2021/09/03
• 4-1-5 異なる土壌における白花ルーピンの根分泌物分布特性の可視化（4-1 植物の多量栄養素 2021年度北海道大会）

  尹 永根, 鈴井 伸郎, 三好 悠太, 海野 佑介, 丸山 隼人, 和崎 淳, 菅 あやね, 圓尾 明子, 渡部 敏裕, 橋本 洋平, 内田 翔子, 信濃 卓郎, 河地 有木

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 45 - 45 0288-5840 2021/09/03
• Ionomic differences between tomato introgression line IL8–3 and its parent cultivar M82 with different trends to the incidence of blossom-end rot

  Toshihiro Watanabe, Ryota Tomizaki, Ryotaro Watanabe, Hayato Maruyama, Takuro Shinano, Masaru Urayama, Yoshinori Kanayama

  Scientia Horticulturae 287 110266 - 110266 0304-4238 2021/09 [Refereed]
   

  Fruit blossom-end rot (BER) is a serious physiological disorder that can cause significant yield losses in tomato (Solanum lycopersicum). Although many studies have suggested that calcium (Ca) deficiency in tomato fruits is a major factor for BER, its onset mechanism has not been fully elucidated. Ionomics is a high-throughput elemental profiling of living organisms that can be applied to understand how differences in plant's physiological status involving inorganic elements. In this study, we examined ionomic differences between the tomato cultivar M82 and its introgression line IL8-3, which contains a short chromosome segment from its wild relative Solanum pennellii on chromosome 8 of M82, and has a low incidence of fruit BER. Among the essential elements, Ca showed marked different behavior between the two lines. IL8-3 showed preferential Ca partitioning to fruits compared with M82. The slow growth rate and high Ca concentration observed in IL8-3 fruit during the early growth stages may also be responsible for the low BER incidence in this line. Although Ca ions bind to cell wall pectin and membrane phospholipids, and contribute to cell structure stability, these components showed no significant differences between fruits of the two lines. The fruit ionome differed considerably between M82 and IL8-3, and was not affected by available Ca status in the field. The M82 fruit had higher concentrations of many elements such as magnesium, potassium, boron, and sulfur than did IL8-3, and this trend was also observed in rotten fruit. This suggests that the influence of the leaf (source), rather than the fruit (sink), could be involved in the onset mechanism of BER.
• Differences in mineral accumulation and gene expression profiles between two metal hyperaccumulators, Noccaea japonica and Noccaea caerulescens ecotype Ganges, under excess nickel condition.

  Takuo Enomoto, Junko Yoshida, Takafumi Mizuno, Toshihiro Watanabe, Sho Nishida

  Plant signaling & behavior 16 (10) 1945212 - 1945212 2021/07/06 [Refereed]
   

  Here we compare mineral accumulation and global gene expression patterns between two metal hyperaccumulator plants - Noccaea japonica, originating from Ni-rich serpentine soils, and Noccaea caerulescens (ecotype Ganges), originating from Zn/Pb-mine soils - under excess Ni conditions. Significant differences in the accumulation of K, P, Mg, B, and Mo were explained by the expression levels of specific transporters for each mineral. We previously showed that total Ni accumulation in the whole plant is higher in N. caerulescens than in N. japonica. Here we found a similar tendency for Fe under excess Ni; however, the expression of iron-regulated transporter 1 (IRT1), which encodes the primary Fe uptake transporter and causes excess Ni uptake in Arabidopsis thaliana, was higher in N. japonica. NjIRT1 has a point mutation at Asp100, which is essential for Fe transport, and so might lack its Fe and possibly Ni transport function. Noccaea japonica might have lost its IRT1 function, which would prevent excess Ni uptake via IRT1 in Ni-rich soils, and come to rely on other transporters.
• Ionomic variation in leaves of 819 plant species growing in the botanical garden of Hokkaido University, Japan.

  Toshihiro Watanabe, Takayuki Azuma

  Journal of plant research 134 (2) 291 - 304 2021/03 [Refereed]
   

  Ionomics is the measurement of total metal, metalloid, and nonmetal accumulation in living organisms. Plant ionomics has been applied to various types of research in the last decade. It has been reported that the ionome of a plant is strongly affected by its evolution and by environmental factors. In this study, we analyzed the concentration of 23 elements in leaves of 819 plant species (175 families) growing in the Botanic Garden of Hokkaido University, Japan. Relative variation estimated by the coefficient of variation in foliar concentrations of essential elements among various plant species tended to be low, whereas nickel concentration showed exceptionally large relative variation. By contrast, the relative variation in nonessential elements was high, particularly in sodium, aluminum, and arsenic. The higher relative variations in these element concentrations can be explained by the occurrence of plants that are hyperaccumulators for these elements. Differences in life forms such as herbaceous/woody species, deciduous/evergreen woody species and annual/perennial herbaceous species affected the concentration of several elements in the leaves. These differences were considered to be due to the combined factors including differences in lifespan, growth rate, and cell wall thickness of the leaves. Results of principal component analyses (based on concentration data of essential and nonessential elements in leaf samples) indicated phylogenetic influences on plant ionomes at the family level in Polypodiales, Pinales, Poales, and Ericales. Furthermore, when analyzing correlations among concentrations of all elements in each order and comparing among different orders, the results also suggested that Polypodiales, Pinales, and Poales each had a specific ion homeostasis network.
• Correction to: Ionomic variation in leaves of 819 plant species growing in the botanical garden of Hokkaido University, Japan.

  Toshihiro Watanabe, Takayuki Azuma

  Journal of plant research 134 (2) 305 - 305 2021/03
• P4-4-3 温度処理にともなう元素吸収・分配がパプリカの尻腐れ果発症に与える影響（4-4 植物の代謝成分と農作物の品質 2021年度北海道大会）

  鳥山 星呂, 荒川 竜太, 村島 和基, 丸山 隼人, 信濃 卓郎, 渡部 敏裕

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 78 - 78 0288-5840 2021
• 4-4-2 異なる窒素条件下におけるパプリカ果実の元素組成と尻腐れ果発症との関係（4-4 植物の代謝成分と農作物の品質 2021年度北海道大会）

  荒川 竜太, 村島 和基, 渡部 敏裕, 信濃 卓郎, 丸山 隼人

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 76 - 76 0288-5840 2021
• 4-4-3 異なる窒素条件下におけるパプリカ果実の機能性成分解析（4-4 植物の代謝成分と農作物の品質 2021年度北海道大会）

  村島 和基, 荒川 竜太, 丸山 隼人, 渡部 敏裕, 信濃 卓郎

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 67 76 - 76 0288-5840 2021
• Effects of Different Potassium Nitrate Concentrations and Temperature Conditions on the Elemental Composition and Blossom-End Rot in Paprika (Capsicum annuum L.)

  Ryota Arakawa, Hisae Fujimoto, Haruka Kameoka, Seiro Toriyama, Yoshihiro Yoshida, Toshihiro Watanabe, Hayato Maruyama

  The Horticulture Journal 一般社団法人 園芸学会 2189-0102 2021 [Refereed]
   

  Blossom-end rot (BER) in paprika (Capsicum annuum L.), as in tomato fruits, is a physiological disorder caused by calcium (Ca) deficiency in fruits. While studies have revealed that excessive nitrogen and potassium fertilization and high temperatures affect Ca transport to fruits and induce BER, few studies have investigated the effects of other elemental concentrations in paprika fruit and their association with BER occurrence. This study aimed to investigate the relationship between the changes in the elemental composition and incidence of BER in paprika fruits grown at different potassium nitrate (KNO₃) concentrations and different temperature conditions. Paprika plants were grown in rockwool blocks in a greenhouse at 25°C and 30°C for approximately four months and irrigated with liquid fertilizer and three different concentrations (0, 27.9, and 74.4 mM) of KNO₃ were added. Subsequently, the total fresh weights of ripe paprika fruits and the incidence of BER were measured, and the elemental compositions in the pericarp of the first and last sampled fruits were analyzed. The total fresh weights significantly decreased and the incidence of BER increased with increasing KNO₃ concentrations and temperature. The profiles of 11 mineral elements in the pericarps of paprika fruits revealed a significant positive or negative correlation between not only the concentration of Ca, but also that of several other elements including boron (which crosslinks pectin in the cell wall like Ca) and the incidence of BER. These results suggest that Ca deficiency may not be the only cause of BER occurrence, and that several elements may also be involved. The insights from this study will contribute to help predict the incidence of BER and stabilize crop production by improving fertilizer application and environmental control.

• Expression genome-wide association study identifies that phosphatidylinositol-derived signalling regulates ALUMINIUM SENSITIVE3 expression under aluminium stress in the shoots of Arabidopsis thaliana.

  Ayan Sadhukhan, Raj Kishan Agrahari, Liujie Wu, Toshihiro Watanabe, Yuki Nakano, Sanjib Kumar Panda, Hiroyuki Koyama, Yuriko Kobayashi

  Plant science : an international journal of experimental plant biology 302 110711 - 110711 2021/01 [Refereed]
   

  To identify unknown regulatory mechanisms leading to aluminium (Al)-induction of the Al tolerance gene ALS3, we conducted an expression genome-wide association study (eGWAS) for ALS3 in the shoots of 95 Arabidopsis thaliana accessions in the presence of Al. The eGWAS was conducted using a mixed linear model with 145,940 genome-wide single nucleotide polymorphisms (SNPs) and the association results were validated using reverse genetics. We found that many SNPs from the eGWAS were associated with genes related to phosphatidylinositol metabolism as well as stress signal transduction, including Ca2+signals, inter-connected in a co-expression network. Of these, PLC9, CDPK32, ANAC071, DIR1, and a hypothetical protein (AT4G10470) possessed amino acid sequence/ gene expression level polymorphisms that were significantly associated with ALS3 expression level variation. Furthermore, T-DNA insertion mutants of PLC9, CDPK32, and ANAC071 suppressed shoot ALS3 expression in the presence of Al. This study clarified the regulatory mechanisms of ALS3 expression in the shoot and provided genetic evidence of the involvement of phosphatidylinositol-derived signal transduction under Al stress.
• Ionomic Responses of Local Plant Species to Natural Edaphic Mineral Variations.

  Chengming Zhang, Syuntaro Hiradate, Yoshinobu Kusumoto, Sayaka Morita, Tomoyo F Koyanagi, Qingnan Chu, Toshihiro Watanabe

  Frontiers in plant science 12 614613 - 614613 2021 [Refereed]
   

  Leaf ionome indicates plant phylogenetic evolution and responses to environmental stress, which is a critical influential factor to the structure of species populations in local edaphic sites. However, little is known about leaf ionomic responses of local plant species to natural edaphic mineral variations. In the present study, all plant species and soil samples from a total of 80 soil sites in Shiozuka Highland were collected for multi-elemental analysis. Ioniomic data of species were used for statistical analysis, representing 24 species and 10 families. Specific preferences to ionomic accumulation in plants were obviously affected by the phylogeny, whereas edaphic impacts were also strong but limited within the phylogenetic preset. Correlations among elements resulted from not only elemental synergy and competition but also the adaptive evolution to withstand environmental stresses. Furthermore, ionomic differences of plant families were mainly derived from non-essential elements. The majority of variations in leaf ionome is undoubtedly regulated by evolutionary factors, but externalities, especially environmental stresses also have an important regulating function for landscape formation, determining that the contributions of each factor to ionomic variations of plant species for adaptation to environmental stress provides a new insight for further research on ionomic responses of ecological speciation to environmental perturbations and their corresponding adaptive evolutions.
• Effects of Different Feedstock Type and Carbonization Temperature of Biochar on Oat Growth and Nitrogen Uptake in Coapplication with Compost

  Shoki Ochiai, Kazunori Iwabuchi, Takanori Itoh, Toshihiro Watanabe, Mitsuru Osaki, Katsumori Taniguro

  JOURNAL OF SOIL SCIENCE AND PLANT NUTRITION 21 (1) 276 - 285 0718-9508 2020/10 

  We aimed to verify whether (i) biochar-compost application improves plant growth when compared with compost application alone and (ii) a diversity of biochar caused by feedstock type and carbonization temperature affects the extent of plant growth. We prepared six types of biochar from larch (Larix kaempferiSarg.) and dairy manure at 300 degrees C, 450 degrees C, and 600 degrees C for 1 h. Compost was applied as control, and each biochar was co-applied with compost to oat plants (Avena sativaL.). The total nitrogen input of all the seven treatments was adjusted to the same level to assess their effects on plant nitrogen uptake and nitrogen content. Compared with the control, biomass production increased from 13.1 to 34.0% with the wood biochar application and from 39.7 to 64.2% with manure biochar application because of more mineralization of compost and nitrogen fixation through rhizobacteria and/or diazotrophic endophytes. The diversity of biochar caused a difference in the extent of oat growth, and feedstock type of biochar was a more dominant factor than carbonization temperature. Due to the favorable chemical properties of manure biochar like high pH and more labile-C and -N content, the manure biochar application increased average biomass production by 26.0% compared with the wood biochar application. The carbonization temperature had no significant impact on oat growth, but the optimal temperature was indicated as approximately 450 degrees C. Biochar diversity causes a difference in plant growth in biochar-compost application, and the selection of appropriate biochar, such as manure biochar at 450 degrees C, would be a guideline for achieving a robust crop production system.
• Heterophyllous Shoots of Japanese Larch Trees: The Seasonal and Yearly Variation in CO2 Assimilation Capacity of the Canopy Top with Changing Environment.

  Satoshi Kitaoka, Qu Laiye, Yoko Watanabe, Makoto Watanabe, Toshihiro Watanabe, Takayoshi Koike

  Plants (Basel, Switzerland) 9 (10) 2020/09/28 [Refereed]
   

  Japanese larch (Larix kaempferi = L. leptolepis) is often characterized by its high growth rate with heterophyllous shoots, but the functional differences of heterophyllous shoots still remain unclear. Recently, abrupt high temperature and drought during spring induced high photosynthetic rate via change in leaf morphology of the deciduous habit. In order to reveal the photosynthetic characteristics of both short and long-shoot needles of sunny canopy of the larch trees using a canopy tower, we calculated the seasonal change of gas exchange characters and leaf mass per area (LMA) and foliar nitrogen content (N) of heterophyllous needles: short and long-shoot needles over 3 years. No marked difference in light-saturated photosynthetic rates (Psat) was observed between short and long shoots after leaf maturation to yellowing, although the difference was obvious in a specific year, which only shows that seasonal change in temperature and soil moisture determines the in situ photosynthetic capacity of needles. The large annual and seasonal variations in Psat in both shoots were found to be mainly determined by climatic variations, while shoot types determined the strategy of their photosynthetic N utilization as well as the stomatal regulation.
• 4-1-35 中国地方の貧栄養な花崗岩質土壌に生育する木本植物の養分吸収特性（4-1 植物の多量栄養素 2020年度岡山大会）

  和崎 淳, 岡村 惟史, 山田 大綱, 愛原 健司, 坪田 博美, 渡部 敏裕

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 66 48 - 48 0288-5840 2020/09/01
• Evaluating Soil–Root Interaction of Hybrid Larch Seedlings Planted under Soil Compaction and Nitrogen Loading

  Tetsuto Sugai, Satoko Yokoyama, Yutaka Tamai, Hirotaka Mori, Enrico Marchi, Toshihiro Watanabe, Fuyuki Satoh, Takayoshi Koike

  Forests 11 (9) 947 - 947 2020/08/29 

  Although compacted soil can be recovered through root development of planted seedlings, the relationship between root morphologies and soil physical properties remain unclear. We investigated the impacts of soil compaction on planted hybrid larch F1 (Larix gmelinii var. japonica×L. kaempferi, hereafter F1) seedlings with/without N loading. We assumed that N loading might increase the fine root proportion of F1 seedlings under soil compaction, resulting in less effects of root development on soil recovery. We established experimental site with different levels of soil compaction and N loading, where two-year-old F1 seedlings were planted. We used a hardness change index (HCI) to quantify a degree of soil hardness change at each depth. We evaluated root morphological responses to soil compaction and N loading, focusing on ectomycorrhizal symbiosis. High soil hardness reduced the total dry mass of F1 seedlings by more than 30%. Significant positive correlations were found between HCI and root proportion, which indicated that F1 seedling could enhance soil recovery via root development. The reduction of fine root density and its proportion due to soil compaction was observed, while these responses were contrasting under N loading. Nevertheless, the relationships between HCI and root proportion were not changed by N loading. The relative abundance of the larch-specific ectomycorrhizal fungi under soil compaction was increased by N loading. We concluded that the root development of F1 seedling accelerates soil recovery, where N loading could induce root morphological changes under soil compaction, resulting in the persistent relationship between root development and soil recovery.
• Effect of mixed cropping with lupin (Lupinus albus L.) on growth and nitrogen uptake in pasture grasses grown under manure application

  Manami Fujiishi, Eriko Maejima, Toshihiro Watanabe

  Archives of Agronomy and Soil Science 66 (1) 96 - 109 0365-0340 2020/01/02 [Refereed]
  
• 14 土壌窒素バランスに対する小麦の葉位別イオノーム解析と光合成機能の関連（北海道支部講演会，2019年度各支部会）

  菅井 徹人, 丸山 隼人, 渡部 敏裕, 信濃 卓郎

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 66 197 - 197 0288-5840 2020
• 13 白花ルーピンのK 欠乏下における根圏土壌中K 及びCs の形態変化（北海道支部講演会，2019年度各支部会）

  藤本 久恵, 高雄 惇英, 丸山 隼人, 俵谷 圭太郎, 信濃 卓郎, 渡部 敏裕

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 66 197 - 197 0288-5840 2020
• 17 ハーブの養分欠乏ストレスと機能性成分とのかかわり（北海道支部講演会，2019年度各支部会）

  伊東 和輝, 渡部 敏裕, 信濃 卓郎, 丸山 隼人

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 66 198 - 198 0288-5840 2020
• 18 ナトリウムによるテンサイの生育促進機構に関する研究（北海道支部講演会，2019年度各支部会）

  小濱 諒太, 合田 健登, 丸山 隼人, 菅井 徹人, 信濃 卓郎, 渡部 敏裕

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 66 198 - 198 0288-5840 2020
• 4-1-24 コムギコアコレクションを用いた根圏リンの形態別評価とリン獲得形質との関係（4-1 植物の多量栄養素 2020年度岡山大会）

  青山 奈央, 森田 洸介, 渡部 敏裕, 信濃 卓郎, 丸山 隼人

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 66 44 - 44 0288-5840 2020
• 4-1-23 土壌リン・窒素制限下におけるダイズの生育とリン獲得経路の経時的評価（4-1 植物の多量栄養素 2020年度岡山大会）

  浅尾 真結子, 渡部 敏裕, 信濃 卓郎, 丸山 隼人

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 66 44 - 44 0288-5840 2020
• 4-3-22 ナトリウムによるテンサイの生育促進と光環境の関係（4-3 植物の有害元素 2020年度岡山大会）

  小濱 諒太, 合田 健登, 丸山 隼人, 菅井 徹人, 信濃 卓郎, 渡部 敏裕

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 66 68 - 68 0288-5840 2020
• 4-3-14 火山性強酸性土壌に生育するツクシテンツキのイオノミクス解析（4-3 植物の有害元素 2020年度岡山大会）

  藤原 久貴, 丸山 隼人, 和崎 淳, 信濃 卓郎, 渡部 敏裕

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 66 65 - 65 0288-5840 2020
• 4-3-10 アルミニウム集積植物 Melastoma marabathricum におけるMATE 遺伝子の機能解析（4-3 植物の有害元素 2020年度岡山大会）

  坂口 文香, 吉井 健祐, 丸山 隼人, 佐々木 孝行, 西田 翔, 和崎 淳, 信濃 卓郎, 渡部 敏裕

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 66 64 - 64 0288-5840 2020
• Does ozone alter the attractiveness of Japanese white birch leaves to a leaf beetle (Agelastica coerulea) via changes in biogenic volatile organic compounds (BVOCs): An examination with the Y-tube test

  Masui N, T Mochizuki, A Tani, H Matsuura, E Agathokleous, T Watanabe, T Koike

  Forests special issue "Impacts of O3 https://www.mdpi.com/1999-4907  2020/01 [Refereed][Not invited]
  
• Brief experimental history of evaluation of the environmental environment (elevated CO2 and O3) on urban and suburb trees with use of a mini-FACE and flux monitoring towers

  小池, 孝良, 江口, 則和, 渡部, 敏裕, 市川, 一, 藤戸, 永志, 曲, 来葉, 渡辺, 誠, 渡邊, 陽子, アガトクレオス, エフゲニオス, 石, 聡, 北尾, 光俊, 高木, 健太郎, 日浦, 勉, 里村, 多賀美, 半, 智史, 船田, 良, 山﨑, 友紀, 佐藤, 冬樹

  Technical report for boreal forest conservation of the Hokkaido University Forests 北海道大学北方生物圏フィールド科学センター森林圏ステーション 37 18 - 26 1344-5855 2019/12
• Metabolic reprogramming in nodules, roots, and leaves of symbiotic soybean in response to iron deficiency.

  Qingnan Chu, Zhimin Sha, Hayato Maruyama, Linzhang Yang, Gang Pan, Lihong Xue, Toshihiro Watanabe

  Plant, cell & environment 42 (11) 3027 - 3043 2019/11 [Refereed][Not invited]
   

  To elucidate the mechanism of adaptation of leguminous plants to iron (Fe)-deficient environment, comprehensive analyses of soybean (Glycine max) plants (sampled at anthesis) were conducted under Fe-sufficient control and Fe-deficient treatment using metabolomic and physiological approach. Our results show that soybeans grown under Fe-deficient conditions showed lower nitrogen (N) fixation efficiency; however, ureides increased in different tissues, indicating potential N-feedback inhibition. N assimilation was inhibited as observed in the repressed amino acids biosynthesis and reduced proteins in roots and nodules. In Fe-deficient leaves, many amino acids increased, accompanied by the reduction of malate, fumarate, succinate, and α-ketoglutarate, which implies the N reprogramming was stimulated by the anaplerotic pathway. Accordingly, many organic acids increased in roots and nodules; however, enzymes involved in the related metabolic pathway (e.g., Krebs cycle) showed opposite activity between roots and nodules, indicative of different mechanisms. Sugars increased or maintained at constant level in different tissues under Fe deficiency, which probably relates to oxidative stress, cell wall damage, and feedback regulation. Increased ascorbate, nicotinate, raffinose, galactinol, and proline in different tissues possibly helped resist the oxidative stress induced by Fe deficiency. Overall, Fe deficiency induced the coordinated metabolic reprogramming in different tissues of symbiotic soybean plants.
• A Reduced Phosphorus Application Rate Using a Mycorrhizal Plant as the Preceding Crop Maintains Soybean Seeds' Nutritional Quality.

  Zhimin Sha, Toshihiro Watanabe, Qingnan Chu, Norikuni Oka, Mitsuru Osaki, Takuro Shinano

  Journal of agricultural and food chemistry 67 (1) 32 - 42 2019/01/09 [Refereed][Not invited]
   

  We tested whether introducing an arbuscular mycorrhizal fungi (AMF)-host plant with a reduced P application rate could maintain soybean seeds' nutrient quality. The dynamic variation of 14 nutrients was analyzed in source and sink organs during the seed-filling stage. The AMF-host and non-AMF-host plants, sunflower and mustard, were grown as preceding crops (PCs). Soybeans, the succeeding crops, were planted with three different phosphorus levels, namely, 0, 50, and 150 kg P2O5 ha-1. The results showed that the AMF-host PC with a reduced P application rate maintained the seed's yield and nutrients quality. During the seed-filling stage, the AMF-host PC with a reduced P application rate increased the uptake of most nutrients compared to the non-AMF-host PC, and improved the remobilization efficiency of all nutrients except Mn, Fe, and Se, compared to the optimal P application rate. These results could help improve the utilization efficiency of P fertilizers and protect soybeans' nutritional value.
• Can needle nitrogen content explain the interspecific difference in ozone sensitivities of photosynthesis between Japanese larch (Larix kaempferi) and Sakhalin fir (Abies sachalinensis)?.

  T. Sugai, M. Kitao, T. Watanabe, T. Koike

  Photosynthetica 57 (2) 540 - 547 0300-3604 2019 [Refereed][Not invited]
  
• Nitrogen loading increases the ozone sensitivity of larch seedlings with higher sensitivity to nitrogen loadin

  Tetsuto Sugai, Toshihiro Watanabe, Kazuhito Kita, Takayoshi Koike

  Science of The Total Environment 663 (1) 587 - 595 0048-9697 2019 [Refereed][Not invited]
  
• Sensitive To Proton Rhizotoxicity1 Regulates Salt and Drought Tolerance of Arabidopsis thaliana Through Transcriptional Regulation of CIPK23

  Ayan Sadhukhan, Takuo Enomoto, Yuriko Kobayashi, Toshihiro Watanabe, Satoshi Iuchi, Masatomo Kobayashi, Lingaraj Sahoo, Yoshiharu Y Yamamoto, Hiroyuki Koyama

  Plant and Cell Physiology 60 (9) 2113 - 2126 2019 [Refereed][Not invited]
  
• Salt Stress Reduced the Seedling Growth of Two Larch Species Under Elevated Ozone

  Tetsuto Sugai, Wang Yannan, Toshihiro Watanabe, Fuyuki Satoh, Laiye Qu, Takayoshi Koike

  Frontiers in Forests and Global Change 2 53  2019 [Refereed][Not invited]
  
• Comparison of the Ability of Several White-rot Fungi to Biobleach Acacia Oxygen-delignified Kraft Pulp

  Sitompul Afrida, Toshihiro Watanabe, Yutaka Tamai

  Asian Journal of Biotechnology and Bioresource Technology 5 (3) 1 - 10 2019 [Refereed][Not invited]
   

  Previous screening analyses demonstrated that the in vivo biobleaching activities of the white-rot fungi Irpex lacteus KB-1.1 and Lentinus tigrinus LP-7 are higher than those of Phanerochaete chrysosporium and Trametes versicolor. The purpose of the current study was to examine the production of extracellular enzymes of these four white-rot fungi grown on three types of low-cost media containing agricultural and forestry waste, and to evaluate the ability of the produced extracellular enzymes to biobleach Acacia oxygen-delignified kraft pulp (A-OKP). The biobleaching activity of extracellular fractions of I. lacteus, L. tigrinus, T. versicolor, and P. chrysosporium cultures was the most pronounced after 3 days of incubation with Acacia mangium wood powder supplemented with rice bran and 1% glucose (WRBG) with resultant Kappa number reduction of 4.4%, 6.7%, 3.3%, and 3.3%, respectively. Therefore, biobleaching ability of I. lacteus and L. tigrinus have been shown to be higher than of T. versicolor and P. chrysosporium, both in vivo and in vitro.
• Dark conditions enhance aluminum tolerance in several rice cultivars via multiple modulations of membrane sterols.

  Tadao Wagatsuma, Eriko Maejima, Toshihiro Watanabe, Tomonobu Toyomasu, Masaharu Kuroda, Toshiya Muranaka, Kiyoshi Ohyama, Akifumi Ishikawa, Masami Usui, Shahadat Hossain Khan, Hayato Maruyama, Keitaro Tawaraya, Yuriko Kobayashi, Hiroyuki Koyama

  Journal of experimental botany 69 (3) 567 - 577 2018/01/23 [Refereed][Not invited]
   

  Aluminum-sensitive rice (Oryza sativa L.) cultivars showed increased Al tolerance under dark conditions, because less Al accumulated in the root tips (1 cm) under dark than under light conditions. Under dark conditions, the root tip concentration of total sterols, which generally reduce plasma membrane permeabilization, was higher in the most Al-sensitive japonica cultivar, Koshihikari (Ko), than in the most Al-tolerant cultivar, Rikuu-132 (R132), but the phospholipid content did not differ between the two. The Al treatment increased the proportion of stigmasterol (which has no ability to reduce membrane permeabilization) out of total sterols similarly in both cultivars under light conditions, but it decreased more in Ko under dark conditions. The carotenoid content in the root tip of Al-treated Ko was significantly lower under dark than under light conditions, indicating that isopentenyl diphosphate transport from the cytosol to plastids was decreased under dark conditions. HMG2 and HMG3 (encoding the key sterol biosynthetic enzyme 3-hydroxy-3-methylglutaryl CoA reductase) transcript levels in the root tips were enhanced under dark conditions. We suggest that the following mechanisms contribute to the increase in Al tolerance under dark conditions: inhibition of stigmasterol formation to retain membrane integrity; greater partitioning of isopentenyl diphosphate for sterol biosynthesis; and enhanced expression of HMGs to increase sterol biosynthesis.
• Effects of ozone (O3) and ethylenediurea (EDU) on the ecological stoichiometry of a willow grown in a free-air exposure system

  Evgenios Agathokleous, Mitsutoshi Kitao, Chu Qingnan, Costas J Saitanis, Elena Paoletti, William J Manning, Toshihiro Watanabe, Takayoshi Koike

  Environmental Pollution 238 663 - 676 0269-7491 2018 [Refereed][Not invited]
   

  Ground-level ozone (O-3) concentrations have been elevating in the last century. While there has been a notable progress in understanding O-3 effects on vegetation, O-3 effects on ecological stoichiometry remain unclear, especially early in the oxidative stress. Ethyelenediurea (EDU) is a chemical compound widely applied in research projects as protectant of plants against O-3 injury, however its mode of action remains unclear. To investigate O-3 and EDU effects early in the stress, we sprayed willow (Salix sachalinensis) plants with 0, 200 or 400 mg EDU L-1, and exposed them to either low ambient O-3 (AOZ) or elevated 03 (EOZ) levels during the daytime, for about one month, in a free air O-3 controlled exposure (FACE); EDU treatment was repeated every nine days. We collected samples for analyses from basal, top, and shed leaves, before leaves develop visible O-3 symptoms. We found that O-3 altered the ecological stoichiometry, including impacts in nutrient resorption efficiency, early in the stress. The relation between P content and Fe content seemed to have a critical role in maintaining homeostasis in an effort to prevent O-3-induced damage. Photosynthetic pigments and P content appeared to play an important role in EDU mode of action. This study provides novel insights on the stress biology which are of ecological and toxicological importance. (C) 2018 Elsevier Ltd. All rights reserved.
• Concentration of some trace elements in two wild edible ferns, Diplazium esculentum and Stenochlaena palutris, inhabiting tropical peatlands under different environments in Central Kalimantan

  Rahmawati Della, Wijaya C. Hanny, Hashidoko Yasuyuki, Djajakirana Gunawan, Haraguchi Akira, Watanabe Toshihiro, Kuramochi Kanta, Nion Yanetri Asi

  Eurasian Journal of Forest Research Hokkaido University Forests, EFRC 20 11 - 20 1345-8221 2017/12 [Refereed][Not invited]
   

  Young leaves of two wild ferns (Diplazium esculentum and Stenochlaena palutris) are uniquely eaten among local peoples in Kalimantan Island. These edible ferns are regarded as important sources of Fe and other trace elements essential for human body. In order to investigate the effect of soil environments on the metal content, we analyzed eight elements (Al, Fe, Cr, Cu, Mn, Zn, Cs, and Pb) in the edible ferns collected from five different sites (riverside of Kahayan River near Bukit Rawi, farming area in Tangkiling, natural forest near Kasongan, and two peat soils at campus of The University of Palangkaraya and residential area in Palangkaraya city) in Central Kalimantan with distinguishable soil conditions. At the five sampling locations, we also collected an aluminum accumulator bush tree (Melastoma malabathricum) as a reference plant. The underground parts of S. palutris and D. esculentum accumulated higher concentration of Al and Fe than their leaf parts, whereas M. malabathricum was rich in Al and Mn in the leaves rather than the roots. Although Fe contents in the edible parts of D. esculentum (3.1–3.3 μg/g-dry weight of young leaves) and S. palutris (1.0–2.1 μg/g dw leaves) from the samples collected at the riverside and the farming area were not so high, Al contents in their edible parts (3.9–6.3 and 7.8–7.9 μg/g-dry weight, respectively) were not excessive. Other trace elements, including Mn, was not the levels to be concerned. Thus, utilizing young leaves and shoots of the ferns as wild vegetable seemed to cover chronical deficiency of trace elements necessary for human nutrition, without any excessive intake of Al and other toxic metals, unless collected at urban area. We further found relatively high Cs-absorbable cropping plants in this study.
• LjMOT1, a high-affinity molybdate transporter from Lotus japonicus, is essential for molybdate uptake, but not for the delivery to nodules.

  Guilan Duan, Tsuneo Hakoyama, Takehiro Kamiya, Hiroki Miwa, Fabien Lombardo, Shusei Sato, Satoshi Tabata, Zheng Chen, Toshihiro Watanabe, Takuro Shinano, Toru Fujiwara

  The Plant journal : for cell and molecular biology 90 (6) 1108 - 1119 2017/06 [Refereed][Not invited]
   

  Molybdenum (Mo) is an essential nutrient for plants, and is required for nitrogenase activity of legumes. However, the pathways of Mo uptake from soils and then delivery to the nodules have not been characterized in legumes. In this study, we characterized a high-affinity Mo transporter (LjMOT1) from Lotus japonicus. Mo concentrations in an ethyl methanesulfonate-mutagenized line (ljmot1) decreased by 70-95% compared with wild-type (WT). By comparing the DNA sequences of four AtMOT1 homologs between mutant and WT lines, one point mutation was found in LjMOT1, which altered Trp292 to a stop codon; no mutation was found in the other homologous genes. The phenotype of Mo concentrations in F2 progeny from ljmot1 and WT crosses were associated with genotypes of LjMOT1. Introduction of endogenous LjMOT1 to ljmot1 restored Mo accumulation to approximately 60-70% of the WT. Yeast expressing LjMOT1 exhibited high Mo uptake activity, and the Km was 182 nm. LjMOT1 was expressed mainly in roots, and its expression was not affected by Mo supply or rhizobium inoculation. Although Mo accumulation in the nodules of ljmot1 was significantly lower than that of WT, it was still high enough for normal nodulation and nitrogenase activity, even for cotyledons-removed ljmot1 plants grown under low Mo conditions, in this case the plant growth was significantly inhibited by Mo deficiency. Our results suggest that LjMOT1 is an essential Mo transporter in L. japonicus for Mo uptake from the soil and growth, but is not for Mo delivery to the nodules.
• Leaf stoichiometry of deciduous tree species in different soils exposed to free-air O-3 enrichment over two growing seasons

  Cong Shi, Toshihiro Watanabe, Takayoshi Koike

  ENVIRONMENTAL AND EXPERIMENTAL BOTANY 138 148 - 163 0098-8472 2017/06 [Refereed][Not invited]
   

  The effects of elevated O-3 in different soil conditions on foliar elements stoichiometry were investigated in 3 native tree species with a free-air enrichment system in northern Japan over two growing seasons. Essential elements (Mg, K, Ca, Mn, Fe, Ni, P, N) and two non-essential elements (Cr, Al) were analyzed in leaf samples obtained from 6 different treatments of O-3 and soils at 5 collection times from 2014 to 2015. In this study, relationships among the foliar elements within each species were investigated and negative correlations between foliar N and the metal elements were observed in birch (Betula platyphylla var. japonica). From the differences of foliar contents as well as their retranslocation rate, beech (Fagus crenata) with determinate shoot growth pattern were rather more sensitive to O-3 stress on foliar contents, meanwhile oak (Quercus mongolica var. crispula) was possibly susceptible to O-3 on dynamics of immobile elements. Soil nutrients have distinct impacts on retranslocation rate of K, Fe, and P. Principal component analysis revealed that Mn and K can become indices in assessing the O-3 and soil effects in both short and long "term monitoring of the growth of these tree species. Our findings are essential in further comprehension to nutrient conservation mechanism in the nutrient dynamics of cool-temperate forests. (C) 2017 Elsevier B.V. All rights reserved.
• The evolution of aluminum accumulation in ferns and lycophytes

  Marco Schmitt, Klaus Mehltreter, Michael Sundue, Weston Testo, Toshihiro Watanabe, Steven Jansen

  AMERICAN JOURNAL OF BOTANY 104 (4) 573 - 583 0002-9122 2017/04 [Refereed][Not invited]
   

  PREMISE OF THE STUDY: This paper investigates the occurrence and evolution of aluminum (Al) accumulation within ferns and lycophytes, which is characterized by Al concentrations above 1000 mg.kg(-1) in aboveground plant tissues. We hypothesize that this feature is more common in ferns than in angiosperms, and potentially correlated with growth form and other chemical elements. METHODS: Aluminum concentrations were obtained from novel analyses and literature for a total of 354 specimens and 307 species. Moreover, a semi-quantitative aluminon test was applied for a subset of 105 species and validated against exact Al measurements. KEY RESULTS: Molecular phylogenetic analyses showed that the major Al-accumulating groups were primarily found in the Gleicheniales and Cyatheales, and largely absent in the Polypodiales. At the species and generic level, Al accumulation was typically either absent or present, and mixed results within a single species and genus were limited to less than 30% of the species and genera tested. Epiphytic ferns had significantly lower Al levels than terrestrial ferns, although this finding was not significant after phylogenetic correction. In addition, a significant, positive correlation was found between Al and iron, while Al was negatively correlated with phosphorus and potassium concentrations. CONCLUSIONS: Aluminum accumulation is most common outside of the Polypodiales and occurs in 38% of the species studied, indicating that this trait is indeed common within subtropical and tropical ferns, a finding that could be in line with their role as pioneer species on landslides and soils with high levels of soluble Al.
• Contrasting Effects of Cattle Manure Applications and Root-Induced Changes on Heavy Metal Dynamics in the Rhizosphere of Soybean in an Acidic Haplic Fluvisol: A Chronological Pot Experiment

  Qingnan Chu, Zhimin Sha, Mitsuru Osaki, Toshihiro Watanabe

  JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 65 (15) 3085 - 3095 0021-8561 2017/04 [Refereed][Not invited]
   

  To characterize the dynamic mobilization of heavy metals (HM) in a crop-soil system affected by cattle manure (CM) application, soybean [Glycine max L. Men. cv. Toyoharuka] crops were exposed in a chronological pot experiment to three CM application rates and sampled at two vegetative stages and two reproductive stages. A sequential extraction procedure for metal fractionation, soil pH, microbial activity, and plant HM uptake was determined. In non-rhizopshere soil, with CM application a liming effect was detected, and increased microbial activity was detected at the reproductive stage. CM application shifted Cd from available state to oxide-bound pool in non-rhizosphere soil; however, shifts in Cd from an oxide-bound pool to the available state were observed in rhizosphere soil. CM application stabilized the available Zn and Pb to oxide-bound Zn and organic-bound Pb in both non-rhizosphere and rhizosphere soils, and the stabilizing degree increased with higher CM application rates. The promoted Zn immobilization in the rhizosphere was due to the liming effects induced by added CM that counteracted the root-induced acidification. On the basis of a stepwise multiple regression analysis, the shift of Cd and Pb fractionation was mainly related to microbial activity. Adding manure inhibited Zn and Pb uptake but promoted Cd uptake by soybean, and a greater influence was detected at the reproductive stage, at which CM application increased the root Cd-absorbing power but did not significantly affect the Zn- and Pb-absorbing powers. In an agricultural context, long-term CM application, even at the recommended rate of 10.13 Mg ha(-1), may cause a soybean Zn deficiency and high Pb accumulation in Haplic Fluvisols, although CM is often considered as an environmentally friendly fertilizer.
• A pronounced improvement of the kappa number reduction and pulp properties associated with the use of extracellular enzymes secreted by selected fungal strains

  Sitompul Afrida, Toshihiro Watanabe, Yutaka Tamai

  Bioresources 12 (4) 8272 - 8285 2017 [Refereed][Not invited]
  
• Differential Responses of Soybean and Sorghum Growth, Nitrogen Uptake, and Microbial Metabolism in the Rhizosphere to Cattle Manure Application: A Rhizobox Study

  Qingnan Chu, Zhimin Sha, Takuji Nakamura, Norikuni Oka, Mitsuru Osaki, Toshihiro Watanabe

  JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 64 (43) 8084 - 8094 0021-8561 2016/11 [Refereed][Not invited]
   

  In this study, we determined the capacity of soybean (Glycine max L. Merr. cv. Hoyoharuka) and sorghum (Sorghum bicolor L. Moench. cv. Hybrid Sorgo) to utilize different forms of nitrogen (N) in a rhizobox system. Seedlings were grown for 35 days without N or with 130 mg N kg(-1) soil as ammonium sulfate or farmyard cattle manure. The soil fractions at different distances from the root were sliced millimeter by millimeter in the rhizobox system. We assessed the distribution of different forms of N and microbial metabolism in different soil fractions in the rhizosphere. There are no treatment-dependent changes in biomass production in the roots and shoots of soybeans, however, the ammonium and manure treatment yielded 1.30 and 1.40 times higher shoot biomass of sorghum than the control. Moreover, the depletion of inorganic N and total amino acids (TAA) in the rhizosphere was largely undetectable at various distances from the soybean roots regardless of the treatments employed. The addition of ammonium sulfate resulted in a decrease in the nitrate concentration gradient as the distance decreased from the sorghum roots. The addition of manure to the soil increased the N content in the sorghum shoots, 1.57 times higher than the control; this increase was negatively correlated with the concentrations of TAA in the soil of the root compartment. In addition, the application of manure simultaneously induced TAA depletion (i.e., the TAA concentration in root compartment was 1.48 times higher than that in bulk soil) and greater microbial activity and diversity in the sorghum rhizosphere, where higher microbial consumption of asparagine, glutamic acid, and phenylalanine were also observed near the roots. Our results are first to present the evidence that sorghum may possess a high capacity for taking up amino acids as a consequence of organic matter application, and microbial metabolism.
• Retranslocation of foliar nutrients of deciduous tree seedlings in different soil condition under free-air O-3 enrichment

  Cong Shi, Norikazu Eguchi, Fankang Meng, Toshihiro Watanabe, Fuyuki Satoh, Takayoshi Koike

  IFOREST-BIOGEOSCIENCES AND FORESTRY 9 (5) 835 - 841 1971-7458 2016/10 [Refereed][Not invited]
   

  Retranslocation is the amount of an element that is depleted from old plant components and is provided for new growth. Leaf senescence is usually accelerated at elevated O-3 (eO(3)), and leaf shedding is influenced by soil nutrient availability (and acidification). In this study, we focused on the net retranslocation and allocation dynamics of foliar nutrients (N, P, Mg, K, Ca, Mn, Fe and Al) to investigate the effect of eO(3) on birch (Betula platyphylla var. japonica), oak (Quercus mongolica var. crispula), and beech (Fagus crenata) seedlings grown in different soil conditions. Seedlings of the 3 species were planted in a free-air O-3 enrichment system under 3 soil types (brown forest soil, serpentine soil, volcanic ash soil) for one growing season. All tree species were grown with 3 replications per each plot at elevated O-3 (about 80 ppb) and ambient condition (O-3 ranging 25-35 ppb). Leaf samples were taken from the top part of seedlings during the growing season in mid-September, and senescing leaves were sampled in mid-November. Both were collected for chemical composition analysis. Retranslocation rate of P was markedly increased by eO(3) in birch and significantly differed among soil types in oak seedlings, while was constant across treatments in beech seedlings. Retranslocation of N in oak seedlings was significantly affected by soil type. Retranslocation of other elements was most sensitive to both eO(3) and soil type in beech seedlings. The influence of differential growth patterns among species in modulating the physiological response of seedlings to high levels of ozone and different soil conditions are discussed.
• The dynamic state of the ionome in roots, nodules, and shoots of soybean under different nitrogen status and at different growth stages

  Qingnan Chu, Toshihiro Watanabe, Takuro Shinano, Takuji Nakamura, Norikuni Oka, Mitsuru Osaki, Zhimin Sha

  JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE 179 (4) 488 - 498 1436-8730 2016/08 [Not refereed][Not invited]
   

  The relative distribution of 22 mineral elements in the roots, nodules and shoots of the soybean (Glycine max L. Merr. cv. Tsurumusume) at R1 (beginning of the flowering stage) and R7 (beginning of the mature stage) was investigated in response to ammonium and manure N treatment. Plants receiving only atmospheric nitrogen served as the negative control. The addition of ammonium sulfate to the soil caused soil acidification, induced Al and Mn toxicities, and significantly reduced the biomass production in roots and nodules. Ca, Mg, Fe, Mn, Cu, and Zn concentrations were significantly higher in shoots, and those of Mo and Co higher in nodules. The addition of manure to the soil significantly enhanced the levels of Sr, Ba, Cr, and Cd in shoots, whereas the concentration of Cs was decreased at R7. Moreover, when the soybean developed from R1 to R7, the levels of essential elements in nodules decreased, whereas those of nonessential elements increased, irrespective of the nitrogen source. Furthermore, the variation in the concentrations of many elements was not consistent for nodules and roots when soybean developed from R1 to R7. The variation of Mn, Zn, B, and Al concentrations was independent of N treatments. However, Ca, Fe, Cu, Mo, and Se levels were affected strongly by N treatments. This study is the first to document the dynamic variation of the soybean ionome in nodules, roots, and shoots from vegetative to reproductive stage of soybean.
• Distribution of minerals in young and mature leaves of different leaf vegetable crops cultivated in a field.

  Watanabe, T, Maejima, E, Urayama, M, Owadano, M, Yamauchi, A, Okada, R, Shinano, T, Osaki, M

  Open Journal of Plant Science 1 (1) 5 - 9 2016/05 [Refereed][Not invited]
  
• Aluminium Accumulation and Intra-Tree Distribution Patterns in Three Arbor aluminosa (Symplocos) Species from Central Sulawesi

  Marco Schmitt, Sven Boras, Aiyen Tjoa, Toshihiro Watanabe, Steven Jansen

  PLOS ONE 11 (2) e0149078  1932-6203 2016/02 [Not refereed][Not invited]
   

  Accumulation of Aluminium (Al) at concentrations far above 1,000 mg kg(-1) in aboveground plant tissues of Arbor aluminosa (Symplocos) species is the main reason why traditional Indonesian weavers rely on their leaves and bark as a mordant for dyeing textile. Recently, Symplocos species have become a flagship species for the conservation efforts of weaving communities due to their traditionally non-sustainable sampling and increasing demand for Symplocos plant material. Here we investigated Symplocos odoratissima, S. ophirensis and S. ambangensis at three montane rainforest sites in Central Sulawesi to measure Al levels in different tissues and organs. The highest Al concentrations were found in old leaves (24,180 +/- 7,236 mg.kg(-1) dry weight, mean +/- SD), while young leaves had significantly lower Al levels (20,708 +/- 7,025 mg.kg(-1)). Al accumulation was also lower in bark and wood tissue of the trunk (17,231 +/- 8,356 mg.kg(-1) and 5,181 +/- 2,032 mg.kg(-1), respectively). Two Al excluding species (Syzigium sp. and Lithocarpus sp.) contained only high Al levels in their roots. Moreover, no difference was found in soil pH (4.7 +/- 0.61) and nutrient (K, Ca, Fe, Mg) availability at different soil levels and within or outside the crown of Symplocos trees, except for the upper soil layer. Furthermore, a positive and significant correlation between Al and Ca concentrations was found at the whole plant level for Symplocos, and at the leaf level for S. ophirensis and S. ambangensis, suggesting a potential role of Ca in Al uptake and/or detoxification within the plant. Our results provide evidence for strong Al accumulation in Symplocos species and illustrate that both Al accumulation and exclusion represent two co-occurring strategies of montane rainforest plants for dealing with Al toxicity. Indonesian weavers should be encouraged to harvest old leaves, which have the most efficient mordant capacity due to high Al concentrations.
• ニホンカラマツとグイマツ雑種F1苗木の光合成能に対するオゾン暴露と硫酸アンモニウム付加の影響

  菅井徹人, 渡部敏裕, 来田和人, 齋藤秀之, 渋谷正人, 小池孝良

  北方森林研究 北方森林学会 64 (64) 63 - 66 2186-7526 2016/02 [Refereed][Not invited]
  
• The Ionomic Study of Vegetable Crops.

  Toshihiro Watanabe, Eriko Maejima, Tomoko Yoshimura, Masaru Urayama, Aiko Yamauchi, Masako Owadano, Ryosuke Okada, Mitsuru Osaki, Yoshinori Kanayama, Takuro Shinano

  PloS one 11 (8) e0160273  2016 [Not refereed][Not invited]
   

  Soil contains various essential and nonessential elements, all of which can be absorbed by plants. Plant ionomics is the study of the accumulation of these elements (the ionome) in plants. The ionomic profile of a plant is affected by various factors, including species, variety, organ, and environment. In this study, we cultivated various vegetable crop species and cultivars under the same field conditions and analyzed the level of accumulation of each element in the edible and nonedible parts using ionomic techniques. The concentration of each element in the edible parts differed between species, which could be partly explained by differences in the types of edible organs (root, leaf, seed, and fruit). For example, the calcium concentration was lower in seeds and fruit than in other organs because of the higher dependency of calcium accumulation on xylem transfer. The concentration of several essential microelements and nonessential elements in the edible parts also varied greatly between cultivars of the same species, knowledge of which will help in the breeding of vegetables that are biofortified or contain lower concentrations of toxic elements. Comparison of the ionomes of the fruit and leaves of tomato (Solanum lycopersicum) and eggplant (S. melongena) indicated that cadmium and boron had higher levels of accumulation in eggplant fruit, likely because of their effective transport in the phloem. We also found that homologous elements that have been reported to share the same uptake/transport system often showed significant correlation only in a few families and that the slopes of these relationships differed between families. Therefore, these differences in the characteristics of mineral accumulation are likely to affect the ionomic profiles of different families.
• Effect of biochar application on mineral and microbial properties of soils growing different plant species

  Anna Hairani, Mitsuru Osaki, Toshihiro Watanabe

  SOIL SCIENCE AND PLANT NUTRITION 62 (5-6) 519 - 525 0038-0768 2016 [Not refereed][Not invited]
   

  Biochar is widely used as a soil amendment to increase crop yields. However, the details of its impact on soil properties have not been fully understood. A pot experiment was conducted using soybean (Glycine max (L.) Merr. cv. Toyoharuka) and sorghum (Sorghum bicolor (L.) Moench cv. Hybrid Sorgo) under four soil treatment combinations (cattle farmyard manure with or without biochar and rapeseed cake with or without biochar) to elucidate the mechanisms of its beneficial effects on plant growth in terms of the microbial community structure and mineral availability in soils with different types of organic manure application. The application of biochar significantly increased the growth of both species, particularly sorghum with rapeseed cake application by 1.48 times higher than that without biochar. Microbial activity in soil was also enhanced by biochar application in both species with rapeseed cake application, particularly in sorghum. Principal component analysis using Biolog EcoPlate (TM) data indicated that biochar application changed the microbial community structure in soil, particularly sorghum-grown soil. The changes in microbial community structure in sorghum were considered to be at least partly affected by changes in soil pH due to interaction between plant and biochar under organic manure application. Biochar application had little effect on the profile of ammonium-acetate-extractable mineral elements in soil including calcium, potassium, magnesium, sodium and sulfur with both types of manure application under soybean. Under sorghum, however, biochar with rapeseed cake manure application altered the profile. This alteration is attributable to an increase in the extractable concentration of certain metals in the soil including aluminum, cadmium and zinc, possibly caused by enhanced organic matter decomposition producing metal-chelating organic compounds. These different changes in the soil properties by biochar application may be directly or indirectly related to the different growth responses of different plant species to biochar application under organic manure application.
• The effects of aluminium on plant growth in a temperate and deciduous aluminium accumulating species

  Marco Schmitt, Toshihiro Watanabe, Steven Jansen

  AOB PLANTS 8 plw065  2041-2851 2016 [Not refereed][Not invited]
   

  Aluminium (Al) is a phytotoxic element affecting the growth and yield of many crop plants, especially in the tropics. Yet, some plants are able to accumulate high levels of Al. The monogeneric family Symplocaceae represents an Al accumulating family including many tropical and evergreen species with high Al levels in their above ground plant tissues. It is unclear, however, whether Al accumulation also characterises temperate species of Symplocos, and whether or not the uptake has a beneficial growth effect. Here, we investigate if the temperate, deciduous species Symplocos paniculata is able to accumulate Al by growing seedlings and saplings in a hydroponic setup at pH 4 with and without Al. Pyrocatechol-violet (PCV) and aluminon staining was performed to visualize Al accumulation in various plant tissues. Both seedlings and saplings accumulate Al in their tissues if available. Mean Al levels in leaves were 4107 (61474mgkg(-1)) and 4290 (64025mgkg(-1)) for the seedlings and saplings, respectively. The saplings treated without Al showed a high mortality rate unlike the Al accumulating ones. The seedlings, however, showed no difference in growth and vitality between the two treatments. The saplings treated with Al showed new twig, leaf and root development, resulting in a considerable biomass increase. PCV and aluminon staining indicated the presence of Al in leaf, wood and bark tissue of the plants. S. paniculata shares the capacity to accumulate Al with its tropical sister species and is suggested to be a facultative accumulator. Whether or not Al has a beneficial effect remains unclear, due to developmental differences between seedlings and saplings. Al is suggested to be transported via the xylem transport system into the leaves, which show the highest Al levels. Radial transport via ray parenchyma to bark tissue is also likely given the high Al concentrations in the bark tissue.
• Contribution of constitutive characteristics of lipids and phenolics in roots of tree species in Myrtales to aluminum tolerance

  Eriko Maejima, Mitsuru Osaki, Tadao Wagatsuma, Toshihiro Watanabe

  Physiologia Plantarum 160 (1) 11 - 20 2016 [Not refereed][Not invited]
  
• Photosynthetic traits of Siebold's beech seedlings in changing light conditions by removal of shading trees under elevated CO2

  M. Watanabe, S. Kitaoka, N. Eguchi, Y. Watanabe, T. Satomura, K. Takagi, F. Satoh, T. Koike

  PLANT BIOLOGY 18 56 - 62 1435-8603 2016/01 [Refereed][Not invited]
   

  The purpose of this study was to obtain basic information on acclimation capacity of photosynthesis in Siebold's beech seedlings to increasing light intensity under future elevated CO2 conditions. We monitored leaf photosynthetic traits of these seedlings in changing light conditions (before removal of shade trees, the year after removal of shade trees and after acclimation to open conditions) in a 10-year free air CO2 enrichment experiment in northern Japan. Elevated CO2 did not affect photosynthetic traits such as leaf mass per area, nitrogen content and biochemical photosynthetic capacity of chloroplasts (i.e. maximum rate of carboxylation and maximum rate of electron transport) before removal of the shade trees and after acclimation to open conditions; in fact, a higher net photosynthetic rate was maintained under elevated CO2. However, in the year after removal of the shade trees, there was no increase in photosynthesis rate under elevated CO2 conditions. This was not due to photoinhibition. In ambient CO2 conditions, leaf mass per area and nitrogen content were higher in the year after removal of shade trees than before, whereas there was no increase under elevated CO2 conditions. These results indicate that elevated CO2 delays the acclimation of photosynthetic traits of Siebold's beech seedlings to increasing light intensity.
• Effects of ozone and/or ammonium sulfate on the photosynthesis and growth of Japanese larch and hybrid larch F₁

  Sugai Tetsuto, Watanabe Toshihiro, Kita Kazuhito, Saito Hideyuki, Shibuya Masato, Koike Takayoshi

  The Japanese Forest Society Congress 日本森林学会 127 730 - 730 2016 

  [in Japanese]
• 4-3-10 低温条件下で栽培したMelastoma malabathricumの生育に対するアルミニウムの効果（4-3 植物の有害元素，2016年度佐賀大会）

  前島 恵理子, 合田 健登, 大崎 満, 渡部 敏裕

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 62 66 - 66 2016
• 4-3-4 Effect of cattle farmyard manure application on heavy metals dynamics in soil and soybean plant（4-3 植物の有害元素，2016年度佐賀大会）

  褚 清南, 渡部 敏裕, 中村 卓司, 岡 紀邦, 大崎 滿

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 62 64 - 64 2016
• 7-2-2 テンサイの擂潰籾殻混合培地が移植後の生育に及ぼす影響（7-2 土壌改良資材，2016年度佐賀大会）

  大竹 勝, 渡部 敏裕, 大崎 満

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 62 137 - 137 2016
• P4-3-7 ストレス条件下でのテンサイの生育に対するナトリウムの効果（ポスター，4-3 植物の有害元素，2016年度佐賀大会）

  南波佐間 幹人, 前島 恵理子, 松本 卓也, 土谷 修平, 大崎 満, 渡部 敏裕

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 62 73 - 73 2016
• P4-2-3 RILsを用いた大豆青立ち耐性機構の解明 1. 包括的元素分析による解析（ポスター，4-2 植物の微量栄養素，2016年度佐賀大会）

  中村 卓司, 山田 哲也, 渡部 敏裕, 岡崎 圭毅

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 62 61 - 61 2016
• 14 テンサイの擂潰籾殻混合育苗培地がペーパーポット紙質へ及ばす影響（北海道支部講演会，2015年度各支部会）

  大竹 勝, 渡部 敏裕, 大崎 満

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 62 243 - 243 2016
• 12 シロバナルーピンで観察される特異的なCs 吸収傾向（北海道支部講演会，2015年度各支部会）

  高雄 惇英, 渡部 敏裕, 和崎 淳, 大崎 満

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 62 242 - 242 2016
• 13 テンサイのカリウム施肥、リン酸施肥及び栽植密度の変動が収量・品質に及ぼす影響の場所間差と土壌分析値との関連について（北海道支部講演会，2015年度各支部会）

  鷹田 秀一, 渡部 敏裕, 大崎 満

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 62 243 - 243 2016
• IV-1 熱帯アジア地域の問題土壌と農業生産 強酸性土壌に生育する植物とアルミニウムの関係（シンポジウム，2016年度佐賀大会）

  渡部 敏裕, 前島 恵理子

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 62 206 - 206 2016
• 8-1-38 Potential effect of wood and bone biochars on greenhouse gas emission of paddy soil under waterlogged and upland conditions（8-1 環境保全，2016年度佐賀大会）

  Hairani Anna, 渡部 敏裕, 長竹 新, Nursyamsi Dedi, 波多野 隆介, 大崎 満

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 62 155 - 155 2016
• 7-1-19 テンサイのカリウム施肥、リン酸施肥が収量・品質に及ぼす影響と土壌分析値との関連及び圃場におけるカリウム・りん酸施肥効果特性の判別について（7-1 肥料および施肥法，2016年度佐賀大会）

  鷹田 秀一, 渡部 敏裕, 大崎 満

  日本土壌肥料学会講演要旨集 一般社団法人 日本土壌肥料学会 62 125 - 125 2016
• Varietal difference in radiocesium uptake and transfer from radiocesium deposited soils in the genus Amaranthus (vol 60, pg 809, 2014)

  Shinano Takuro, Watanabe Toshihiro, Chu Qingnan

  SOIL SCIENCE AND PLANT NUTRITION 62 (5-6) 569  0038-0768 2016 [Refereed][Not invited]
  
• Ionomic Analysis of Horticultural Plants Reveals Tissue-specific Element Accumulation

  Tomoki Shibuya, Toshihiro Watanabe, Hirold Ikeda, Yoshinori Kanayama

  HORTICULTURE JOURNAL 84 (4) 305 - 313 2189-0102 2015/10 [Not refereed][Not invited]
   

  Ionomic analysis was performed in three diverse fruit crops in order to characterize element concentrations in edible parts and to compare element concentrations between edible parts and vegetative organs and between species. Nineteen elements, including elements essential for human health, toxic elements, and elements with radioisotopes from nuclear reactors, were analyzed in apple (Malta domestica), Japanese pear (Pyrus pyrifolia), eggplant (Solanum melongena), and edamame (Glycine max). The concentrations of elements were shown as basic information needed for biofortification, and high mobilities depending on plant species were found for some elements whose mobilities are believed to be low. Classification of element profiles into the leaf (or the leaf blade) and other organs containing edible parts, except the calyx, by principal component analysis revealed similarity in the element concentrations across species. The present study may contribute to progress in the ionomic studies of fruit crops.
• Growth of Japanese and hybrid larch seedlings grown under free-air O-3 fumigation-an initial assessment of the effects of adequate and excessive nitrogen

  Kam Dong-Gyu, Cong Shi, Makoto Watanabe, Kazuhito Kita, Fuyuki Satoh, Takayoshi Koike

  JOURNAL OF AGRICULTURAL METEOROLOGY 71 (3) 239 - 244 0021-8588 2015/09 [Refereed][Not invited]
   

  Ground-surface ozone (O-3) and nitrogen (N) deposition in forests are increasing rapidly in East Asia. The Japanese larch (JL) has been transplanted from central Japan to northern areas. Because the JL suffers from shoot blight disease and grazing by voles, the hybrid larch (F-1) was developed to overcome these weak points. For sustainable use of these larches, we should know the growth responses of larches to elevated O-3 (eO(3)) and excessive N deposition in northern Japan. Two-year-old JL and F-1 seedlings were potted in well-weathered immature volcanic ash soil with basal dressing of balanced fertilizer containing 47 kgN ha(-1) yr(-1), due to a lack of nutrients in the soil. To simulate eO(3), seedlings were grown in a free-air O-3 fumigation system (60 nmol mol(-1) in daytime). Also, to simulate acid rain, NH4NO3 (50 kgN ha(-1) yr(-1) in total) was applied to the plants. Independent of the N loading, the dry mass of needle litter in both JL and F-1 was less at eO(3) than at ambient O-3. Re-translocation of N before the needle shedding of both larches was lower under eO(3). As a result, the aboveground biomass per needle (i.e. productive efficiency) was higher at eO(3).
• Interactions between Cs, Sr, and other nutrients and trace element accumulation in Amaranthus shoot in response to variety effect.

  Qingnan Chu, Toshihiro Watanabe, Zhimin Sha, Mitsuru Osaki, Takuro Shinano

  Journal of agricultural and food chemistry 63 (8) 2355 - 63 2015/03/04 [Not refereed][Not invited]
   

  Aiming at clarifying the interactions between Cs, Sr, and other mineral elements in the genus Amaranthus, this study adopted 33 different varieties of Amaranthus and investigated the concentrations of 23 mineral elements in shoots grown in the fields of Iino in Fukushima prefecture. Significant varietal effects were detected for all elements except Se, and degree of interspecies variation was highly element dependent. Among 23 elements, amaranths were less sensitive to the accumulation of Cs and Sr than most other mineral elements to the species level. There are six elements showing significant correlation with Cs, positive correlations between As, Rb, Al, Fe, Ni, and Cs, and negative correlation between Ba and Cs. Significant correlations between Ca, Mg, Mn, Zn, B, Ba, Cd, and Sr were detected, and all of the coefficients were positive. Cs and Sr did not present significant correlation, but they were both significantly correlated with Ba. By principal component analysis (PCA), the first and second principal components (PC1 and PC2) accounted for 23.2 and 20.3% of the total variance and associated with Cs and Sr, respectively. Both of the two species took up more Cs by promoting the influx of elements positively correlated with Cs into shoot, but at the same time, Amaranthus hypochondriacus (L.) Mapes 847 decreased the K and Ba uptake and Amaranthus powellii (S. Wats) subsp. Powellii inhibited the accumulation of Rb, Sr, and significantly correlated elements of Sr in shoot. This study is the first to pave the way for comprehension on ionome in amaranth shoot at the variety level. The results of this research provide the ionomic basis for implementing countermeasures in the field against the translocation of Cs (and potentially Sr) toward crops and food.
• Higher sterol content regulated by CYP51 with concomitant lower phospholipid content in membranes is a common strategy for aluminium tolerance in several plant species

  Tadao Wagatsuma, Md. Shahadat Hossain Khan, Toshihiro Watanabe, Eriko Maejima, Hitoshi Sekimoto, Takao Yokota, Takeshi Nakano, Tomonobu Toyomasu, Keitaro Tawaraya, Hiroyuki Koyama, Matsuo Uemura, Satoru Ishikawa, Takashi Ikka, Akifumi Ishikawa, Takeshi Kawamura, Satoshi Murakami, Nozomi Ueki, Asami Umetsu, Takayuki Kannari

  JOURNAL OF EXPERIMENTAL BOTANY 66 (3) 907 - 918 0022-0957 2015/02 [Not refereed][Not invited]
   

  Several studies have shown that differences in lipid composition and in the lipid biosynthetic pathway affect the aluminium (Al) tolerance of plants, but little is known about the molecular mechanisms underlying these differences. Phospholipids create a negative charge at the surface of the plasma membrane and enhance Al sensitivity as a result of the accumulation of positively charged Al3+ ions. The phospholipids will be balanced by other electrically neutral lipids, such as sterols. In the present research, Al tolerance was compared among pea (Pisum sativum) genotypes. Compared with Al-tolerant genotypes, the Al-sensitive genotype accumulated more Al in the root tip, had a less intact plasma membrane, and showed a lower expression level of PsCYP51, which encodes obtusifoliol-14 alpha-demethylase (OBT 14DM), a key sterol biosynthetic enzyme. The ratio of phospholipids to sterols was higher in the sensitive genotype than in the tolerant genotypes, suggesting that the sterol biosynthetic pathway plays an important role in Al tolerance. Consistent with this idea, a transgenic Arabidopsis thaliana line with knocked-down AtCYP51 expression showed an Al-sensitive phenotype. Uniconazole-P, an inhibitor of OBT 14DM, suppressed the Al tolerance of Al-tolerant genotypes of maize (Zea mays), sorghum (Sorghum bicolor), rice (Oryza sativa), wheat (Triticum aestivum), and triticale (xTriticosecale Wittmark cv. Currency). These results suggest that increased sterol content, regulated by CYP51, with concomitant lower phospholipid content in the root tip, results in lower negativity of the plasma membrane. This appears to be a common strategy for Al tolerance among several plant species.
• Application of ionomics to plant and soil in fields under long-term fertilizer trials.

  Toshihiro Watanabe, Masaru Urayama, Takuro Shinano, Ryosuke Okada, Mitsuru Osaki

  SpringerPlus 4 (1) 781 - 781 2015 [Not refereed][Not invited]
   

  Ionomics is the study of elemental accumulation in living organisms using high-throughput elemental profiling. In the present study, we examined the ionomic responses to nutrient deficiency in maize grown in the field in long-term fertilizer trials. Furthermore, the available elements in the field soils were analyzed to investigate their changes under long-term fertilizer treatment and the ionomic relationships between plant and soil. Maize was cultivated in a field with the following five long-term fertilizer treatments: complete fertilization, fertilization without nitrogen, without phosphorus, without potassium, and no fertilization. Concentrations of 22 elements in leaves at an early flowering stage and in soils after harvest were determined. The fertilizer treatments changed the availabilities of many elements in soils. For example, available cesium was decreased by 39 % and increased by 126 % by fertilizations without nitrogen and potassium, respectively. Effects of treatments on the ionome in leaves were evaluated using the translocation ratio (the concentration in leaves relative to the available concentration in soils) for each element. Nitrogen deficiency specifically increased the uptake ability of molybdenum, which might induce the enhancement of nitrogen assimilation and/or endophytic nitrogen fixation in plant. Potassium deficiency drastically enhanced the uptake ability of various cationic elements. These elements might act as alternatives to K in osmoregulation and counterion of organic/inorganic anions. Two major groups of elements were detected by multivariate analyses of plant ionome. Elements in the same group may be linked more or less in uptake and/or translocation systems. No significant correlation between plant and soil was found in concentrations of many elements, even though various soil extraction methods were applied, implying that the interactions between the target and other elements in soil must be considered when analyzing mineral dynamics between plant and soil.
• Varietal difference in radiocesium uptake and transfer from radiocesium deposited soils in the genus Amaranthus

  Takuro Shinano, Toshihiro Watanabe, Qingnan Chu, Mitsuru Osaki, Daisuke Kobayashi, Toshiyasu Okouchi, Hisaya Matsunami, Osamu Nagata, Keiki Okazaki, Takuji Nakamura

  SOIL SCIENCE AND PLANT NUTRITION 60 (6) 809 - 817 0038-0768 2014/11 [Not refereed][Not invited]
   

  Within Amaranthaceae, 33 different varieties, including local varieties from Japan, were grown in 2012 in a field in the town of Iino in the Fukushima prefecture, which is located approximately 51km north of Tokyo Electric Power Company, Fukushima Daiichi Nuclear Power Plant (FDNPP). The contamination level of the soil was 2770 +/- 140Bq kg(-1) dry weight ((134)Cesium (Cs)+Cs-137, average +/- SE), and the field was also cultivated in 2011. There was a significant varietal difference in the dry weight production, radiocesium accumulation and transfer factor (TF) of radiocesium from the soil to the plant. The ratio of the lowest TF to the highest TF was approximately 3. Because the ratio of Cs-137 to Cs-133 was significantly positive, radiocesium seems to be absorbed in a manner similar to that of Cs-133. It is suggested that the varietal difference in the behavior of radiocesium uptake mainly depends on its genetic background rather than on environmental factors.
• Biobleaching of Acacia kraft pulp with extracellular enzymes secreted by Irpex lacteus KB-1.1 and Lentinus tigrinus LP-7 using low-cost media

  Sitompul Afrida, Yutaka Tamai, Toshihiro Watanabe, Mitsuru Osaki

  WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY 30 (8) 2263 - 2271 0959-3993 2014/08 [Not refereed][Not invited]
   

  The white-rot fungi Irpex lacteus KB-1.1 and Lentinus tigrinus LP-7 have been shown in previous studies to have high biobleaching activity in vivo. The aim of this study was to investigate the activities and stabilities of extracellular enzymes, prepared from I. lacteus and L. tigrinus culture grown in three types of economical media of agricultural and forestry wastes, for biobleaching of Acacia oxygen-delignified kraft pulp using kappa number reduction as an indicator of delignification. After 3 days of incubation, the extracellular enzymes preparations from I. lacteus and L. tigrinus cultures in media of Acacia mangium wood powder supplemented with rice bran and addition 1 % glucose (WRBG), resulted in significant decrease of 4.4 and 6.7 %, respectively. A slightly higher kappa number reduction (7.4 %) was achieved with the combine extracellular enzymes from I. lacteus and L. tigrinus. One of the strategies for reducing the cost of enzyme production for treatment processes in the pulp and paper industry is the utilization of agricultural and forestry waste. Thus, WRBG has potential as a culture medium for producing stable lignolytic enzymes simply and economically.
• Rice RCN1/OsABCG5 mutation alters accumulation of essential and nonessential minerals and causes a high Na/K ratio, resulting in a salt-sensitive phenotype

  Shuichi Matsuda, Hidetaka Nagasawa, Nobuhiro Yamashiro, Naoko Yasuno, Toshihiro Watanabe, Hideyuki Kitazawa, Sho Takano, Yoshihiko Tokuji, Masayuki Tani, Itsuro Takamure, Kiyoaki Kato

  PLANT SCIENCE 224 103 - 111 0168-9452 2014/07 [Not refereed][Not invited]
   

  Mineral balance and salt stress are major factors affecting plant growth and yield. Here, we characterized the effects of rice (Oryza sativa L) reduced culm number1 (rcn1), encoding a G subfamily ABC transporter (OsABCG5) involved in accumulation of essential and nonessential minerals, the Na/K ratio, and salt tolerance. Reduced potassium and elevated sodium in field-grown plants were evident in rcn1 compared to original line 'Shiokari' and four independent rcn mutants, rcn2, rcn4, rcn5 and rcn6. A high Na/K ratio was evident in the shoots and roots of rcn1 under K starvation and salt stress in hydroponically cultured plants. Downregulation of SKC1/OsHRT1 ;5 in rcn1 shoots under salt stress demonstrated that normal function of RCN1/OsABCG5 is essential for upregulation of SKC1/OsHKT1 ;5 under salt stress. The accumulation of various minerals in shoots and roots was also altered in the rcn1 mutant compared to 'Shiokari' under control conditions, potassium starvation, and salt and b-sorbitol treatments. The rcn1 mutation resulted in a salt-sensitive phenotype. We concluded that RCN1/OsABCG5 is a salt tolerance factor that acts via Na/K homeostasis, at least partly by regulation of SICC1/OsHKT1 ;5 in shoots. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
• Comparative analysis of aluminum accumulation in leaves of three angiosperm species

  Eriko Maejima, Syuntaro Hiradate, Steven Jansen, Mitsuru Osaki, Toshihiro Watanabe

  BOTANY-BOTANIQUE 92 (5) 327 - 331 1916-2790 2014/05 [Not refereed][Not invited]
   

  Aluminum (Al) accumulators are widely distributed in the plant kingdom but phylogenetic implications of internal Al detoxification mechanisms are not well understood. We investigated differences in the characteristics of Al accumulation (i.e., accumulation potential, chemical form, and localization) in three woody Al accumulators, Symplocos chinensis (Lour.) Druce var. leucocarpa (Nakai) Ohwi f. pilosa (Nakai) Ohwi (Symplocaceae, Ericales), Melastoma malabathricum L., and Tibouchina urvilleana Cogn. (both Melastomataceae, Myrtales). The order of Al accumulation potential under hydroponic conditions was S. chinensis approximate to M. malabathricum > T. urvilleana. Oxalate was at least partly involved in the internal Al detoxification mechanisms in leaves of all three Al accumulators, based on a correlation analysis between Al and organic acid in water and 0.02 mol.L-1 HCl extracts and the Al-27 nuclear magnetic resonance spectra of intact leaves. However, the Al forms in the leaves were not simple Al-ligand complexes in a specific cell structure. Al localization in leaf sections differed among the three species. Extremely high levels of Al were found in trichomes of the lower epidermis in leaves of T. urvilleana. These data illustrate that woody Al-accumulating angiosperms have independently developed various internal Al-tolerance mechanisms in which oxalate plays a significant role.
• Phosphorus deficiency enhances aluminum tolerance of rice (Oryza sativa) by changing the physicochemical characteristics of root plasma membranes and cell walls

  Eriko Maejima, Toshihiro Watanabe, Mitsuru Osaki, Tadao Wagatsuma

  JOURNAL OF PLANT PHYSIOLOGY 171 (2) 9 - 15 0176-1617 2014/01 [Not refereed][Not invited]
   

  The negative charge at the root surface is mainly derived from the phosphate group of phospholipids in plasma membranes (PMs) and the carboxyl group of pectins in cell walls, which are usually neutralized by calcium (Ca) ions contributing to maintain the root integrity. The major toxic effect of aluminum (Al) in plants is the inhibition of root elongation due to Al binding tightly to these negative sites in exchange for Ca. Because phospholipid and pectin concentrations decrease in roots of some plant species under phosphorus (P)-limiting conditions, we hypothesized that rice (Oryza sativa L) seedlings grown under P-limiting conditions would demonstrate enhanced Al tolerance because of their fewer sites on their roots. For pretreatment, rice seedlings were grown in a culture solution with (+P) or without (-P) P. Thereafter, the seedlings were transferred to a solution with or without Al, and the lipid, pectin, hemicellulose, and mineral concentrations as well as Al tolerance were then determined. Furthermore, the low-Ca tolerance of P-pretreated seedlings was investigated under different pH conditions. The concentrations of phospholipids and pectins in the roots of rice receiving -P pretreatment were lower than those receiving +P pretreatment. As expected, seedlings receiving the -P pretreatment showed enhanced Al tolerance, accompanied by the decrease in Al accumulation in their roots and shoots. This low P-induced enhanced Al tolerance was not explained by enhanced antioxidant activities or organic acid secretion from roots but by the decrease in phospholipid and pectin concentrations in the roots. In addition, low-Ca tolerance of the roots was enhanced by the -P pretreatment under low pH conditions. This low P-induced enhancement of low-Ca tolerance may be related to the lower Ca requirement to maintain PM and cell wall structures in roots of rice with fewer phospholipids and pectins. (C) 2013 Elsevier GmbH. All rights reserved.
• Arsenic alters uptake and distribution of sulphur in Pteris vittata.

  Toshihiro Watanabe, Ran Kouho, Tomo Katayose, Nobuyuki Kitajima, Naoya Sakamoto, Noriko Yamaguchi, Takuro Shinano, Hisayoshi Yurimoto, Mitsuru Osaki

  Plant, cell & environment 37 (1) 45 - 53 2014/01 [Not refereed][Not invited]
   

  Low-molecular-weight thiol (LMWT) synthesis has been reported to be directly induced by arsenic (As) in Pteris vittata, an As hyperaccumulator. Sulphur (S) is a critical component of LMWTs. Here, the effect of As treatment on the uptake and distribution of S in P. vittata was investigated. In P. vittata grown under low S conditions, the presence of As in the growth medium enhanced the uptake of SO4(2-), which was used for LMWT synthesis in fronds. In contrast, As application did not affect SO4(2-) uptake in Nephrolepis exaltata, an As non-hyperaccumulator. Moreover, the isotope microscope system revealed that S absorbed with As accumulated locally in a vacuole-like organelle in epidermal cells, whereas S absorbed alone was distributed uniformly. These results suggest that S is involved in As transport and/or accumulation in P. vittata. X-ray absorption near-edge structure analysis revealed that the major As species in the fronds and roots of P. vittata were inorganic As(III) and As(V), respectively, and that As-LMWT complexes occurred as a minor species. Consequently, in case of As accumulation in P. vittata, S possibly acts as a temporary ligand for As in the form of LMWTs in intercellular and/or intracellular transport (e.g. vacuolar sequestration).
• Proportion of phospholipids in the plasma membrane is an important factor in Al tolerance

  Eriko Maejima, Toshihiro Watanabe

  Plant Signaling and Behavior 9 (MAY) e29277  1559-2324 2014 [Not refereed][Not invited]
   

  The negative charge on the plasma membrane (PM) is mainly derived from the phosphate group of phospholipids. One of the mechanisms of aluminum (Al) toxicity is to increase the PM permeability of root cells by binding to the negative sites on the PM. Thus, PM with a higher proportion of phospholipids could be more susceptible to Al toxicity. In our previous study, we showed that tolerance to Al and low-calcium in rice was enhanced by decreasing the proportion of phospholipids in root cells. Both Melastoma malabathricum L. and Melaleuca cajuputi Powell are dominant woody species that grow in tropical acid sulfate soils, and have been reported to be more tolerant to Al than rice. Surprisingly, the proportion of PM phospholipids in root cells of M. malabathricum and M. cajuputi was considerably low. Our present findings suggest that PM lipid composition plays an important role in Al tolerance mechanisms in various plant species. © 2014 Landes Bioscience.
• Comparative analysis of aluminum accumulation in leaves of three angiosperm species

  Eriko Maejima, Syuntaro Hiradate, Steven Jansen, Mitsuru Osaki, Toshihiro Watanabe

  Botany 92 (5) 327 - 331 1916-2804 2014 [Refereed][Not invited]
   

  Aluminum (Al) accumulators are widely distributed in the plant kingdom but phylogenetic implications of internal Al detoxification mechanisms are not well understood. We investigated differences in the characteristics of Al accumulation (i.e., accumulation potential, chemical form, and localization) in three woody Al accumulators, Symplocos chinensis (Lour.) Druce var. leucocarpa (Nakai) Ohwi f. pilosa (Nakai) Ohwi (Symplocaceae, Ericales), Melastoma malabathricum L., and Tibouchina urvilleana Cogn. (both Melastomataceae, Myrtales). The order of Al accumulation potential under hydroponic conditions was S. chinensis ≈ M. malabathricum > T. urvilleana. Oxalate was at least partly involved in the internal Al detoxification mechanisms in leaves of all three Al accumulators, based on a correlation analysis between Al and organic acid in water and 0.02 mol·L-1 HCl extracts and the 27Al nuclear magnetic resonance spectra of intact leaves. However, the Al forms in the leaves were not simple Al-ligand complexes in a specific cell structure. Al localization in leaf sections differed among the three species. Extremely high levels of Al were found in trichomes of the lower epidermis in leaves of T. urvilleana. These data illustrate that woody Al-accumulating angiosperms have independently developed various internal Al-tolerance mechanisms in which oxalate plays a significant role.
• Molecular and Physiological Analysis of Al3+ and H+ Rhizotoxicities at Moderately Acidic Conditions

  Yasufumi Kobayashi, Yuriko Kobayashi, Toshihiro Watanabe, Jon E. Shaff, Hiroyuki Ohta, Leon V. Kochian, Tadao Wagatsuma, Thomas B. Kinraide, Hiroyuki Koyama

  PLANT PHYSIOLOGY 163 (1) 180 - 192 0032-0889 2013/09 [Not refereed][Not invited]
   

  Al3+ and H+ toxicities predicted to occur at moderately acidic conditions (pH [water] = 5-5.5) in low-Ca soils were characterized by the combined approaches of computational modeling of electrostatic interactions of ions at the root plasma membrane (PM) surface and molecular/physiological analyses in Arabidopsis (Arabidopsis thaliana). Root growth inhibition in known hypersensitive mutants was correlated with computed {Al3+} at the PM surface ({Al3+}(PM)); inhibition was alleviated by increased Ca, which also reduced {Al3+}(PM) and correlated with cellular Al responses based on expression analysis of genes that are markers for Al stress. The Al-inducible Al tolerance genes ALUMINUM-ACTIVATED MALATE TRANSPORTER1 and ALUMINUM SENSITIVE3 were induced by levels of {Al3+}(PM) too low to inhibit root growth in tolerant genotypes, indicating that protective responses are triggered when {Al3+}(PM) was below levels that can initiate injury. Modeling of the H+ sensitivity of the SENSITIVE TO PROTON RHIZOTOXICITY1 knockout mutant identified a Ca alleviation mechanism of H+ rhizotoxicity, possibly involving stabilization of the cell wall. The phosphatidate phosphohydrolase1 (pah1) pah2 double mutant showed enhanced Al susceptibility under low-P conditions, where greater levels of negatively charged phospholipids in the PM occur, which increases {Al3+}(PM) through increased PM surface negativity compared with wild-type plants. Finally, we found that the nonalkalinizing Ca fertilizer gypsum improved the tolerance of the sensitive genotypes in moderately acidic soils. These findings fit our modeling predictions that root toxicity to Al3+ and H+ in moderately acidic soils involves interactions between both toxic ions in relation to Ca alleviation.
• Effect of Phosphorus Levels on the Protein Profiles of Secreted Protein and Root Surface Protein of Rice

  Takuro Shinano, Tomoko Yosihmura, Toshihiro Watanabe, Yusuke Unno, Mitsuru Osaki, Yohei Nanjo, Setsuko Komatsu

  Journal of Proteome Research 12 (11) 4748 - 4756 1535-3893 2013 [Not refereed][Not invited]
   

  Plant roots are complicated organs that absorb water and nutrients from the soil. Roots also play an essential role in protecting plants from attack by soil pathogens and develop a beneficial role with some soil microorganisms. Plant-derived rhizosphere proteins (e.g., root secretory proteins and root surface binding proteins) are considered to play important roles in developing mutual relationships in the rhizosphere. In the rhizosphere, where plant roots meet the surrounding environment, it has been suggested that root secretory protein and root surface binding protein are important factors. Furthermore, it is not known how the physiological status of the plant affects the profile of these proteins. In this study, rice plants were grown aseptically, with or without phosphorus nutrition, and proteins were obtained from root bathing solution (designated as root secretory proteins) and obtained using 0.2 M CaCl2 solution (designated as root surface binding proteins). The total number of identified proteins in the root bathing solution was 458, and the number of root surface binding proteins was 256. More than half of the proteins were observed in both fractions. Most of the proteins were categorized as either having signal peptides or no membrane transport helix sites. The functional categorization suggested that most of the proteins seemed to have secretory pathways and were involved in defense/disease-related functions. These characteristics seem to be unique to rhizosphere proteins, and the latter might be part of the plants strategy to defeat pathogens in the soil. The low phosphorus treatment significantly increased the number of pathogenesis-related proteins in the root secretory proteins, whereas the change was small in the case of the root surface binding proteins. The results suggested that the roots are actively and selectively secreting protein into the rhizosphere.
• Ionome of Soybean Seed Affected by Previous Cropping with Mycorrhizal Plant and Manure Application

  Zhimin Sha, Norikuni Oka, Toshihiro Watanabe, Biatna Dulbert Tampubolon, Keiki Okazaki, Mitsuru Osaki, Takuro Shinano

  JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 60 (38) 9543 - 9552 0021-8561 2012/09 [Not refereed][Not invited]
   

  Two field experiments were conducted to investigate the effects of previous cultivation of an arbuscular mycorrhizal (AM) host plant and manure application on the concentration of 19 mineral elements in soybean (Glycine max L. Merr. cv. Tsurumusume) seeds. Each experiment ran for two years (experiment 1 took place in 2007-2008, and experiment 2 took place in 2008-2009) with a split plot design. Soybeans were cultivated after growing either an AM host plant (maize, Zea mays L. cv. New dental) or a non-AM host plant (buckwheat, Fagopyrum esculentum Moench. cv. Kitawase-soba) in the first year in the main plots, with manure application (0 and 20 t/ha) during the soybean season in split plots from both main plots. On the basis of the two experiments, manure application significantly increased the available potassium (K) and decreased the available iron (Fe) and cesium (Cs) in the soil. However, higher concentrations of cadmium (Cd) and barium (Ba) and lower concentrations of Cs in the seed were induced by the application of manure. Cd levels in the seed were decreased by prior cultivation with the AM host plant. The present study showed that the identity of the prior crop and manure application changed the mineral contents of the soybean seed and suggests a connection between environmental factors and food safety.
• Effect of exogenous phosphatase and phytase activities on organic phosphate mobilization in soils with different phosphate adsorption capacities

  Hayato Maruyama, Takuya Yamamura, Yohei Kaneko, Hirokazu Matsui, Toshihiro Watanabe, Takuro Shinano, Mitsuru Osaki, Jun Wasaki

  SOIL SCIENCE AND PLANT NUTRITION 58 (1) 41 - 51 0038-0768 2012 [Not refereed][Not invited]
   

  This study evaluated the effects of exogenous LASAP2 for acid phosphatase (APase) and LASAP3 for phytase of white lupin (Lupinus albus L.) on phosphorus (P) accumulation from organic P in soils. The potential for LASAP2-overexpressing tobacco (Nicotiana tabacum L.) to increase organic P in soil was examined in our previous study. However, LASAP2 has low specificity for phytate, the predominant form of unavailable P in the brown lowland soil. For the present study, we isolated the full length of LASAP3 cDNA and introduced it into tobacco plants using Agrobacterium-mediated transformation. Transgenic tobacco plants were grown in two different soils (Andosols and Regosols; high and low P-adsorption capacity, respectively) supplemented with either inorganic phosphate (+Pi) or phytate (Po) as the sole P source, or control conditions that lacked phosphorus (No P). Dry matter production and P content of the transgenic line was higher than that of wild type in all treatments. The ratio of P accumulation increase by exogenous enzymes was found to be dependent on the P treatment and soil type. In all lines, the increase in +Po was less than that in +Pi, but higher than in No P. The P uptake ability of plants in Regosols was higher than in Andosols for all treatments, suggesting that the P utilization efficiency of both Pi and Po is dependent on the solubility. In no soil type or P treatment was a significant difference found between LASAP2- and LASAP3-overexpressing lines. These results demonstrate that introducing an APase and phytase gene such as LASAP2 and LASAP3 into tobacco by genetic transformation is a promising strategy for improving P mobilization in soil, although the bottleneck for mobilization of phytate-P is not the specificity of the enzyme but its solubility in soils.
• DIFFERENCES IN ACQUISITION OF ORGANIC NITROGEN IN SOILS BETWEEN BOK CHOY AND TOMATO

  Toshihiro Watanabe, Takumi Enomoto, Michihiko Sakurai, Miwa Okamoto, Takuro Shinano, Mitsuru Osaki

  JOURNAL OF PLANT NUTRITION 35 (10) 1468 - 1476 0190-4167 2012 [Not refereed][Not invited]
   

  Seedlings of bok choy and tomato were grown in soils with different nitrogen (N) sources [no N (-N), ammonium sulfate (AS), and cattle farmyard manure (CM)]. Comparison between soils treated with -N and CM indicated that the growth and N accumulation in bok choy were significantly enhanced by CM treatment, whereas no difference was found in tomato. In the rhizosphere soils, the highest protease activity was detected in CM treatment irrespective of species. Correlation analysis between rhizospheric protease activity and total N accumulation of plant treated with {N and CM showed a significant positive correlation only for bok choy. The determination of amino acid absorption rate in excised roots indicated that glycine was taken up at a significantly higher rate in bok choy than tomato. This study suggested that at least two possible factors affected the acquisition of organic N: rhizospheric protease activity and ability to absorb amino acids in roots.
• Metabolite Profiling of Mizuna (Brassica rapa L var. Nipponsinica) To Evaluate the Effects of Organic Matter Amendments

  Ayano Watanabe, Keiki Okazaki, Toshihiro Watanabe, Mitsuru Osaki, Takuro Shinano

  Journal of Agricultural and Food Chemistry 61 (5) 1009 - 1016 2012 [Not refereed][Not invited]
  
• Ionomic response of Lotus japonicus to different root-zone temperatures

  Quazi Forhad Quadir, Toshihiro Watanabe, Zheng Chen, Mitsuru Osaki, Takuro Shinano

  SOIL SCIENCE AND PLANT NUTRITION 57 (2) 221 - 232 0038-0768 2011/04 [Not refereed][Not invited]
   

  The effects of root-zone temperature (RZT) on the ion uptake, distribution and interactions of 21 (11 essential and 10 non-essential) elements using Lotus japonicus were studied. After acclimation in hydroponics at ambient (25 degrees C) RZT for three weeks, seedlings were exposed to sub-optimal (15 degrees C and 20 degrees C) and ambient RZTs. After one week, plants were harvested and then growth and mineral elements were analyzed. The highest shoot and root biomass was at 25 degrees C and lowest at 15 degrees C RZT. In shoots, the highest concentrations of all elements, except for nickel (Ni), were at 25 degrees C RZT. At lower RZTs, the reductions in concentrations were more evident especially for trace elements and heavy metals. Except for magnesium (Mg), the highest root concentrations were at 15 degrees C RZT for all essential elements. Unlike other non-essential elements, the highest cadmium (Cd) and cobalt (Co) concentrations in roots were at 25 degrees C RZT. The shoot/root ratios of almost all elements were affected by sub-optimal RZTs. Only manganese (Mn) and Co showed increased shoot/root ratio at sub-optimal RZTs; and this ratio decreased for other elements. Nickel in shoots and Mn, Co and Cd in roots tended to be negatively correlated with most other elements (either, essential or non-essential) in each respective organ. The present study showed that RZT significantly changed the ion profile of L. japonicus and suggests possible connection between global warming and phyto-accumulation of heavy metals, especially in temperate regions, since most metals tended to accumulate in shoots at higher RZT.
• Proteomic analysis of secreted proteins from aseptically grown rice

  T. Shinano, S. Komatsu, T. Yoshimura, S. Tokutake, F. -J. Kong, T. Watanabe, J. Wasaki, M. Osaki

  PHYTOCHEMISTRY 72 (4-5) 312 - 320 0031-9422 2011/03 [Not refereed][Not invited]
   

  Plants are known to secrete a variety of compounds into the rhizosphere. These compounds are thought to play important roles in the regulation of soil chemical properties and soil microorganisms. To determine the composition of proteins secreted from rice roots, aseptic hydro culture was performed, and the collected proteins were analyzed. Over 100 proteins were identified; most were identified using the rice database (RAP-DB), and about 60% of the identified proteins were suspected to have a signal peptide. Functional categorization suggested that most were secondary metabolism-and defense-related proteins. Pathogenesis-and stress-related proteins were the major proteins found in the bathing solution under aseptic conditions. Thus, we propose that rice plants constitutively secrete a large variety of proteins to protect their roots against abiotic and/or biotic stresses in the environment. (C) 2010 Elsevier Ltd. All rights reserved.
• Changes in saccharide, amino acid and S-methylmethionine content during malting of barley grown with different nitrogen and sulfur status

  Masahito Nanamori, Toshihiro Watanabe, Takuro Shinano, Makoto Kihara, Kazumitsu Kawahara, Shinji Yamada, Mitsuru Osaki

  JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 91 (1) 85 - 93 0022-5142 2011/01 [Not refereed][Not invited]
   

  BACKGROUND: Changes in saccharide, amino acid and S-methylmethionine (SMM) concentrations and enzyme activities during the malting of barley grown with different nitrogen (N) and sulfur (S) supplementation were investigated in order to clarify their relationship with N and S fertiliser levels. RESULTS: Concentrations of N and S in barley grain were significantly increased by the addition of N to the culture soil. Application of N decreased the starch concentration in grain. On the other hand, higher N fertilisation increased the beta-glucan concentration in grain and malt, thus decreasing the accessibility of beta-glucanase to its substrates. Proteolytic enzyme activity was significantly higher in the absence (-N treatment) than in the presence (+N treatment) of N fertiliser, making the concentration of the majority of amino acids in malt slightly higher in the -N treatment. SMM was synthesised in grain after imbibition, and application of N increased the SMM content in malt. CONCLUSION: Although SMM can be controlled to a certain extent during kilning, a balanced supply of N and S during cultivation can also be helpful for the production of malt with lower SMM concentration. Adequate soil management is desirable to maintain the balance between good agronomic performance and high malt quality. (C) 2010 Society of Chemical Industry
• Influence of arsenic stress on synthesis and localization of low-molecular-weight thiols in Pteris vittata

  Yuki Sakai, Toshihiro Watanabe, Jun Wasaki, Takeshi Senoura, Takuro Shinano, Mitsuru Osaki

  ENVIRONMENTAL POLLUTION 158 (12) 3663 - 3669 0269-7491 2010/12 [Not refereed][Not invited]
   

  The roles of low-molecular-weight thiols (LMWTs), such as glutathione and phytochelatins, in arsenic (As) tolerance and hyperaccumulation in Pteris vittata an As-hyperaccumulator fern remain to be better understood. This study aimed to thoroughly characterize LMWT synthesis in P. vittata to understand the roles played by LMWTs in As tolerance and hyperaccumulation. LMWT synthesis in P. vittata was induced directly by As, and not by As-mediated oxidative stress. Expression of PvECS2. one of the putative genes of gamma-glutamylcysteine synthetase (gamma ECS), increases in P. vittata shoots at 48 h after the onset of As exposure, almost corresponding to the increase in the concentrations of gamma-glutamylcysteine and glutathione. Furthermore, localization of As showed similar trends to those of LMWTs in fronds at both whole-frond and cellular levels. This study thus indicates the specific contribution of LMWTs to As tolerance in P. vittata. gamma ECS may be responsible for the As-induced enhancement of LMWT synthesis. (C) 2010 Elsevier Ltd. All rights reserved.
• Promotion of root growth by the application of inosine

  Dai Tokuhisa, Takuro Shinano, Toshihiro Watanabe, Takuya Yamamura, Mitsuru Osaki

  SOIL SCIENCE AND PLANT NUTRITION 56 (2) 272 - 280 0038-0768 2010/04 [Not refereed][Not invited]
   

  The aim of the present study was to verify the effect of inosine on plant growth. Rice (Oryza sativa L.), tomato (Solanum lycopersicum L.), onion (Allium cepa L.), sunflower (Helianthus annuus L.) and soybean (Glycine max (L.) Merr.) seedlings were grown in a hydroponic system with different added concentrations of inosine (0, 7.2, 72 and 373 mu mol L-1) in a greenhouse. The application of inosine improved the growth of all plant parts, particularly roots, except for soybean. The optimum inosine concentration for plant growth was 72 mu mol L-1. Furthermore, in rice, tomato and sunflower, treatment with inosine increased root length. To confirm the effect of inosine, an aseptic experiment was carried out using rice plants in a hydroponic system and using tomato in a rhizobox system with sterile soil. The positive effect of inosine was also confirmed under aseptic conditions in rice and tomato, indicating that inosine directly enhances plant growth without microbial decomposition.
• Screening of white rot fungi for biobleaching of Acacia oxygen-delignified kraft pulp

  Sitompul Afrida, Yutaka Tamai, Toshihiro Watanabe, Mitsuru Osaki

  WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY 25 (4) 639 - 647 0959-3993 2009/04 [Not refereed][Not invited]
   

  To reduce the levels of chlorine-based chemicals in Acacia kraft pulp, we sought to isolate white rot fungus strains that could be used for biobleaching. For this purpose, we collected 600 fungal sources from Indonesia and subjected them to a three-step screening method. The first step involved culturing the strains on Acacia mangium wood powder, guaiacol and agar (WGA) medium. Of the 600 sources, 258 strains grew on WGA medium and generated a red color. The second step revealed that 31 of the 258 strains could degrade extractive-free A. mangium wood powder. The third step examined the ability of the strains to bleach A. mangium oxygen-delignified kraft pulp (A-OKP) under various pH conditions and showed that five strains could biobleach A-OKP at pH 5, 6, and 8. In contrast, the biobleaching abilities of Trametes versicolor and Phanerochaete chrysosporium, which served as standards, were much lower than those of the five new strains, particularly at pH 8. These five strains may be useful for biobleaching of A-OKP.
• Element interconnections in Lotus japonicus: A systematic study of the effects of element additions on different natural variants

  Zheng Chen, Toshihiro Watanabe, Takuro Shinano, Tatsuhiro Ezawa, Jun Wasaki, Kazuhiko Kimura, Mitsuru Osaki, Yong-Guan Zhu

  SOIL SCIENCE AND PLANT NUTRITION 55 (1) 91 - 101 0038-0768 2009/02 [Not refereed][Not invited]
   

  Lotus japonicus was used to study the distribution and interconnections of 15 elements in plant tissues, including essential and non-essential elements: boron (B), sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), strontium (Sr), molybdenum (Mo), cadmium (Cd) and cesium (Cs). Large amounts of B and Ca accumulated in plant leaves, while Fe, Na, Ni, As and Cd tended to mainly occur in the roots, and Mo was the only element to accumulate in the stems. The elemental compositions within plants were severely disturbed by treatment with toxic elements. Competition between element pairs in the same group (e.g. K and Cs; Ca and Sr) was not found. Iron, Cu and Zn accumulation were induced by Cd and Ni addition. When natural variants grew in a nutrition solution with subtoxic levels of As, Cd, Cs, Ni, Mo and Sr, intriguing relationships between the elements (such as Fe, As and K; Mg and Ni; Mn and Ca) were revealed using principal-component analysis. This study on the plant ionome offers detailed information of element interactions and indicates that chemically different elements might be closely linked in uptake or translocation systems.
• Analysis of Diversity of Diazotrophic Bacteria Associated with the Rhizosphere of a Tropical Arbor, Melastoma malabathricum L.

  Atsuya Sato, Toshihiro Watanabe, Yusuke Unno, Erry Purnomo, Mitsuru Osaki, Takuro Shinano

  MICROBES AND ENVIRONMENTS 24 (2) 81 - 87 1342-6311 2009 [Not refereed][Not invited]
   

  The diversity of diazotrophic bacteria in the rhizosphere of Melastoma malabathricum L. was investigated by cloning-sequencing of the nifH gene directly amplified from DNA extracted from soil. Samples were obtained from the rhizosphere and bulk soil of M. malabathricum growing in three different soil types (acid sulfate, peat and sandy clay soils) located very close to each other in south Kalimantan, Indonesia. Six clone libraries were constructed, generated from bulk and rhizosphere soil samples, and 300 nifH clones were produced, then assembled into 29 operational taxonomic units (OTUs) based on percent identity values. Our results suggested that nifH gene diversity is mainly dependent on soil properties, and did not differ remarkably between the rhizosphere and bulk soil of M. malabathricum except in acid sulfate soil. In acid sulfate soil, as the Shannon diversity index was lower in rhizosphere than in bulk soil, it is suggested that particular bacterial species might accumulate in the rhizosphere.
• Mechanisms of Aluminum Tolerance in Phosphoenolpyruvate Carboxylase Transgenic Rice

  Begum HH, Mitsuru Osaki, Toshihiro Watanabe, Takuro Shinano

  Journal of Plant Nutrition 32 (1) 84 - 96 2009 [Not refereed][Not invited]
  
• Rapid characterization of plant mutants with an altered ion-profile: a case study using Lotus japonicus

  Zheng Chen, Toshihiro Watanabe, Takuro Shinano, Keiki Okazaki, Mitsuru Osaki

  NEW PHYTOLOGIST 181 (4) 795 - 801 0028-646X 2009 [Not refereed][Not invited]
   

  Legumes are second only to cereals in their importance to humans, and study of their functional genomics of nutrition and other trace elements is crucial for agricultural production and food fortification. We describe here an ionomic screening experiment carried out to investigate the accumulation of 15 elements in shoots of mutants of Lotus japonicus, a good genetic tool for legume study. Approximately 2000 mutagenized M2 plants were cultivated in a novel low-cost high-throughput system and their elemental profiles were determined by inductively coupled plasma mass spectroscopy (ICP-MS). After triple-checking the element concentrations in M2 or M3 plant shoots, 31 mutants with altered elemental profiles were identified. Surprisingly, the number of genes regulating essential elements was similar to the number regulating nonessential elements. Magnesium (Mg) and nickel (Ni) were correlated in a number of mutants. Further investigation suggested that phosphorus (P) and cobalt (Co) might be involved in the ion homeostasis network of Mg and Ni. The results suggested that the pathways for element uptake or translocation were highly linked through the ion transport-related genes. Ionomics proved to be a powerful functional genomics tool for determining genes related to ion homeostasis in this study. New Phytologist (2009) 181: 795-801doi: 10.1111/j.1469-8137.2008.02730.x.
• Effect of Zero-Valent Iron Application on Cadmium Uptake in Rice Plants Grown in Cadmium-Contaminated Soils

  Toshihiro Watanabe, Yasutoshi Murata, Takashi Nakamura, Yuki Sakai, Mitsuru Osaki

  JOURNAL OF PLANT NUTRITION 32 (7) 1164 - 1172 0190-4167 2009 [Not refereed][Not invited]
   

  Cadmium (Cd) contamination in soils is a serious problem for crop production in the world. Zero-valent iron [Fe (0)] is a reactive material with reducing power capable of stabilizing toxic elements in a solution. In the present study, we examined the effect of zero-valent iron [Fe (0)] application on Cd accumulation in rice plants growing in Cd-contaminated paddy soils. The application of 1.0 and 0.5 mg Fe (0) per 100 g soils significantly reduced the Cd concentration in seeds and leaves by less than 10% and 20% of those without Fe (0) application, respectively. The form of Cd in soil was determined by sequential extraction. The Fe (0) application increased the free-oxides-occluded (less available) Cd content, and decreased the exchangeable and iron-manganese-oxides-bound (more available) Cd content, in Cd-contaminated soils. Thus, this study clearly showed that the application of Fe (0) is a promising approach for remediation of Cd-contaminated paddy soils.
• Amaranthus Tricolor Has the Potential for Phytoremediation of Cadmium-Contaminated Soils

  Toshihiro Watanabe, Yasutoshi Murata, Mitsuru Osaki

  COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 40 (19-20) 3158 - 3169 0010-3624 2009 [Not refereed][Not invited]
   

  Phytoremediation is a developing technology that uses plants to clean up pollutants in soils. To adopt this technology to cadmium (Cd)-contaminated soils efficiently, a Cd hyperaccumulator with fast growth rate and large biomass is required. In the present study, we selected Caryophyllales as a potential clade that might include Cd hyperaccumulators because this clade had a high mean concentration of zinc (Zn), which is in the same element group as Cd. Three species in Caryophyllales and three species in different clades were grown with Cd. Among them, Amaranthus tricolor showed high accumulating ability for Cd under both water-culture and soil-culture conditions, whereas Brassica juncea, a known Cd hyperaccumulator, accumulated high concentrations of Cd in shoots only under water-culture conditions. This result suggests that A. tricolor has Cd-solubilizing ability in rhizosphere. Because A. tricolor has large biomass and high growth rate, this species could be useful for phytoremediation of Cd-contaminated fields.
• Effects of nitrogen application on malt modification and dimethyl sulfide precursor production in two Japanese barley cultivars

  Masahito Nanamori, Ryoichi Kanatani, Makoto Kihara, Kazumitsu Kawahara, Katsuhiro Hayashi, Toshihiro Watanabe, Takuro Shinano, Mitsuru Osaki

  JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 88 (8) 1464 - 1471 0022-5142 2008/06 [Not refereed][Not invited]
   

  BACKGROUND: Nitrogenous components have a great influence on both malt and beer qualities. Barley storage proteins are degraded during the germination process, in which amino acids and small peptides are released. Some of these compounds relate to dimethyl sulfide precursor production in the malting process. In this study, barley and malt qualities were investigated using two Japanese barley cultivars, Sukai Golden and Mikamo Golden, with several different nitrogen (N) treatments. RESULTS: Nitrogen top-dressing treatments efficiently increased N and sulfur (S) concentrations in grains. A difference in malt modification was induced by these treatments without any change in protease activity in malts. S-Methyl methionine (SMM) concentration in malt of Sukai Golden with low-N treatment was 1.8-2.1 times higher than that with higher-N treatments. Methionine concentration in malts was not significantly affected by N treatments of both cultivars, while grain S level was not consistent under any treatments. CONCLUSION: Results show that low-N treatment increases SMM concentration in malts despite major S-containing amino acids of malts being not highly affected by the difference in nutrient status of grains. Further investigations are necessary into aspects of both metabolic profiles in barley germination and SMM degradation in the kilning process. (c) 2008 Society of Chemical Industry.
• Characterization of root mucilage from Melastoma malabathricum, with emphasis on its roles in aluminum accumulation

  Toshihiro Watanabe, Seiji Misawa, Syuntaro Hiradate, Mitsuru Osaki

  NEW PHYTOLOGIST 178 (3) 581 - 589 0028-646X 2008/05 [Not refereed][Not invited]
   

  Plant roots exude viscous polysaccharides, called mucilage. One of the suggested roles of mucilage is immobilization of toxic metal cations, including aluminum (Al), in the rhizosphere. Mucilage exuded from roots of Melastoma malabathricum (Al accumulator) was characterized in comparison with that of Zea mays (maize; Al nonaccumulator). Removal of mucilage significantly reduced Al accumulation in M. malabathricum. The cation adsorption affinity of M. malabathricum mucilage was higher for Al and lanthanum (La) than for barium (Ba), whereas that of maize mucilage was in the order Ba > La > Al. A (27)Al nuclear magnetic resonance (NMR) spectrum of the Al-adsorbed mucilage and bioassay with alfalfa seedlings indicated that the concentrated Al in the mucilage of M. malabathricum, unlike that of maize, bound very weakly to cation exchange sites of mucilage. The higher charge density in M. malabathricum mucilage, derived from unmethylated uronic acid, is inferred to be related to preferential adsorption of trivalent cation. Not only a higher degree of methylation in the uronic acid (glucuronic acid) but also H(+) release from roots to the mucilage appears to be responsible for the loose binding of Al in M. malabathricum mucilage. These characteristics of mucilage may help Al hyperaccumulation in M. malabathricum.
• Biotransformation of (+)-catechin into taxifolin by a two-step oxidation: Primary stage of (+)-catechin metabolism by a novel (+)-catechin-degrading bacteria, Burkholderia sp KTC-1, isolated from tropical peat

  Motoki Matsuda, Yuichiro Otsuka, Shigeki Jin, Jun Wasaki, Jun Watanabe, Toshihiro Watanabe, Mitsuru Osaki

  BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 366 (2) 414 - 419 0006-291X 2008/02 [Not refereed][Not invited]
   

  Peat contains various persistent compounds derived from plant materials. We isolated a novel (+)-catechin-degrading bacterium, Burkholderia sp. KTC-1 (KTC-1), as an example of a bacterium capable of degrading persistent aromatic compounds present in tropical peat. This bacterium was isolated by an enrichment technique and grew on (+)-catechin as the sole carbon source under acidic conditions. The reaction of a crude enzyme extract and a structural study of its products showed that (+)-catechin is biotransformed into taxifolin during the preliminary stages of its metabolism by KTC-1. HPLC analysis showed that this transformation occurs in two oxidation steps: 4-hydroxylation and dehydrogenation. Furthermore, both (+)-catechin 4-hydroxylanase and leucocyanidin 4-dehydrogenase were localized in the cytosol of KTC-1. This is the first report on biotransformation of (+)-catechin into taxifolin via leucocyanidin by an aerobic bacterium. We suggest that tropical peat could become a unique resource for microorganisms that degrade natural aromatic compounds. (C) 2007 Elsevier Inc. All rights reserved.
• Advances in developing screening methods and improving aluminum resistance in common bean and Brachiaria

  Idupulapati Rao, Peter Wenzl, Adriana Arango, John Miles, Toshihiro Watanabe, Takuro Shinano, Mitsuru Osaki, Tadao Wagatsuma, Germ?n Manrique, Stephen Beebe, Joe Tohme, Manabu Ishitani, Andr?s Rangel, Walter Horst

  Current Agricultural Science and Technology 14 (4) 1 - 7 2008 [Not refereed][Not invited]
  
• Root mucilage enhances aluminum accumulation in Melastoma malabathricum, an aluminum accumulator

  Toshihiro Watanabe, Seiji Misawa, Syuntaro Hiradate, Mitsuru Osaki

  Plant Signaling and Behavior 3 (8) 603 - 605 1559-2324 2008 [Not refereed][Not invited]
   

  Root mucilage is gelatinous polysaccharide-containing material exuded from the outer layers of the root cap. Although mucilage has been suggested to play several roles in plant growth, its role in mineral uptake has not been well understood. Melastoma malabathricum L. is an aluminum (Al) accumulator growing in tropical acid soils. This species accumulates more than 10 mg Al g -1 DW in leaves and roots. Root mucilage is generally known to immobilize metal cations such as Al in the rhizosphere. However, we found that roots of M. malabathricum exuded large amounts of mucilage. Using the Zea mays L. mucilage as a control, we have recently shown that mucilage of M. malabathricum has unique physical and chemical characteristics, and facilitates Al uptake in this species. Since M. malabathricum cannot grow well in Al-deficient soil (nonacid soils), this species might have developed a mechanism for Al acquisition. We have also discussed the reason for this species' requirement of Al, a nonessential element. ©2008 Landes Bioscience.
• Sago (Metroxylon sagu Rottb.) growth is affected by weeds in a tropical peat swamp in Thailand

  Monrawee Yanbuaban, Mitsuru Osaki, Tanit Nuyim, Jumpen Onthong, Toshihiro Watanabe

  SOIL SCIENCE AND PLANT NUTRITION 53 (3) 267 - 277 0038-0768 2007/06 [Not refereed][Not invited]
   

  The effect of weeds on sago palms (Metroxylon sagu Rottb.) growing in tropical peat soils was examined in the field and in pots. In the field, 31 species of weeds were found, however, Fimbristylis umbellaris (Cyperraceae) and Leersia hexandra (Gramineae) were the most abundant species. Sago heights and weed populations seemed to be correlated. The field experiment showed that high dense L. hexandra was less positively correlated to sago growth, while high dense F. umbellaris was moderately negatively correlated. A study of the effects of F. umbellaris and L. hexandra was required because of the complexity of the weed composition in the field, and also because of the difficulties in evaluating which species have individually affected sago growth. In a pot experiment, L. hexandra accumulated high amounts of P and Zn, and markedly suppressed the growth of sago palms compared with F. umbellaris. In contrast, sago withstood weed competition by increasing root dry matter, however, yellowing of the leaves occurred in response to the low concentration of N observed in sago tissues. Sago palms planted with L. hexandra, F. umbellaris or weeds themselves showed a significant correlation with N-2-fixing symbioses by having higher foliar delta N-15 than soil delta N-15. Leersia hexandra demonstrated the highest correlation with N-2-fixation symbioses. This capability of L. hexandra may be the reason that it is a stronger competitor for sago growth when compared with F. umbellaris. In conclusion, N-2-fixation symbioses are more important than soil nutrition under N-limited peat soil. Moreover, N-2-fixation symbioses could be induced during the competition of plant species rather than in the absence of competitive plants.
• Screening of phosphate-solubilizing microorganisms in rhizosphere and rhizoplane of adverse soil-adapting plants in Southern Thailand

  Ashara Pengnoo, Yasuyuki Hashidoko, Jumpen Onthong, Sayjai Gimsanguan, Manoon Sae-ong, Takuro Shinano, Toshihiro Watanabe, Mitsuru Osaki

  Tropics 日本熱帯生態学会 16 (1) 10 - 7 0917-415X 2007 [Not refereed][Not invited]
   

  Various adverse soils; peat, podzolic sandy, acid sulfate and salted-affected acid sulfate soils were widely distributed throughout Southern Thailand. These soils were infertile and strongly acidic. Phosphorus fertility of these soils was low due to the low content of available phosphorus (0.31-3.70 mg kg-1) especially in podzolic sandy soil. Acid sulfate soil and salt-affected acid sulfate soil contain relatively high level of exchangeable Al (13.3 and 9.87 cmolc kg-1, respectively). However, some native plants; Melaleuca cajuputi, Melastoma malabathricum, Scleria sumatrensis and Oryza sativa grow well in these adverse soils. Since the adverse soils distributed there are phosphorus-unavailable soils. Hence, base on an idea that phosphate-solubilizing microorganism is a key factor for plant growth, such functional rhizospherous microorganisms were screened using modified Pikovskaya,s media containing 5 mg l-1 P in different phosphate forms, Al-PO4, Fe-PO4 and Na-phytate, and adjusted pH 4.0. The number of microorganisms in the rhizosphere tended to be lower than in the rhizoplane. Twelve isolates showed remarkable growth performance on these solid media. Among these selected, 5 strains were obtained from acid sulfate soil, suggesting acid sulfate soil-adapting plant is a good source of the phosphate-solubilizing microorganism.
• Nutritional ecology of plants grown in a tropical peat swamp

  Monrawee YANBUABAN, Tanit NUYIM, Takeshi MATSUBARA, Toshihiro WATANABE, Mitsuru OSAKI

  Tropics 日本熱帯生態学会 16 (1) 31 - 39 0917-415X 2007 [Not refereed][Not invited]
  
• Evolutionary control of leaf element composition in plants

  Toshihiro Watanabe, Martin R. Broadley, Steven Jansen, Philip J. White, Jitsuya Takada, Kenichi Satake, Takejiro Takamatsu, Sehat Jaya Tuah, Mitsuru Osaki

  NEW PHYTOLOGIST 174 (3) 516 - 523 0028-646X 2007 [Not refereed][Not invited]
   

  Leaf nitrogen (N) and phosphorus (P) concentrations are correlated in plants. Higher-level phylogenetic effects can influence leaf N and P. By contrast, little is known about the phylogenetic variation in the leaf accumulation of most other elements in plant tissues, including elements with quantitatively lesser roles in metabolism than N, and elements that are nonessential for plant growth. Here the leaf composition of 42 elements is reported from a statistically unstructured data set comprising over 2000 leaf samples, representing 670 species and 138 families of terrestrial plants. Over 25% of the total variation in leaf element composition could be assigned to the family level and above for 21 of these elements. The remaining variation corresponded to differences between species within families, to differences between sites which were likely to be caused by soil and climatic factors, and to variation caused by sampling techniques. While the majority of variation in leaf mineral composition is undoubtedly associated with nonevolutionary factors, identifying higher-level phylogenetic variation in leaf elemental composition increases our understanding of terrestrial nutrient cycles and the transfer of toxic elements from soils to living organisms. Identifying mechanisms by which different plant families control their leaf elemental concentration remains a challenge.
• Al-Fe interactions and growth enhancement in Melastoma malabathricum and Miscanthus sinensis dominating acid sulphate soils

  Toshihiro Watanabe, Steven Jansen, Mitsuru Osaki

  PLANT CELL AND ENVIRONMENT 29 (12) 2124 - 2132 0140-7791 2006/12 [Not refereed][Not invited]
   

  Plants growing in acid sulphate soils are subject to high levels of Al availability, which may have effects on the growth and distribution of these species. Although Fe availability is also high in acid sulphate soils, little is known about the effect of Fe on the growth of native plants in these soils. Two species dominating this soil type in Asia, viz. Melastoma malabathricum and Miscanthus sinensis were grown hydroponically in a nutrient solution with different concentrations of Al and Fe. Melastoma malabathricum is found to be sensitive to Fe (40 and 100 mu M). Application of 500 mu M Al, however, completely ameliorates Fe toxicity and is associated with a decrease of Fe concentration in shoots and roots. The primary reason for the Al-induced growth enhancement of M. malabathricum is considered to be the Al-induced reduction of toxic Fe accumulation in roots and shoots. Therefore, Al is nearly essential for M. malabathricum when growing in acid sulphate soils. In contrast, application of both Fe and Al does not reduce the growth of M. sinensis, and Al application does not result in lower shoot concentrations of Fe, suggesting that this grass species has developed different mechanisms for adaptation to acid sulphate soils.
• Internal mechanisms of plant adaptation to aluminum toxicity and phosphorus starvation in three tropical forages

  Toshihiro Watanabe, Mitsuru Osaki, Hiromi Yano, Idupulapati M. Rao

  JOURNAL OF PLANT NUTRITION 29 (7) 1243 - 1255 0190-4167 2006/07 [Not refereed][Not invited]
   

  Many tropical forage grasses and legumes grow well in acid soils, adapting to excess aluminum (Al) and phosphorus (P) starvation stresses by using mechanisms that are still unclear. To determine these mechanisms, responses to Al toxicity and P starvation in three tropical forages were studied: two grasses, Brachiaria hybrid cv. 'Mulato' (B. ruziziensis clone 44-06 x B. brizantha cv. 'Marandu') and Andropogon gayanus, and one legume, Arachis pintoi. The tropical grasses tolerated high levels of At toxicity and P starvation, with the Brachiaria hybrid maintaining very low levels of Al concentration in shoots. Al-27 Nuclear Magnetic Resonance spectroscopy (NMR) analysis revealed that, in the Brachiaria hybrid, Al makes complexes with some ligands such as organic-acid anions in the root symplast. The forages probably adapted to P starvation through high P-use efficiency. These experiments provide the first direct evidence we know of that organic acid anions within root tissue help detoxify A] in non-accumulator species such as the Brachiaria hybrid.
• Role of phosphoenolpyruvate carboxylase in the adaptation of a tropical forage grass to low-phosphorus acid soils

  HH Begum, M Osaki, M Nanamori, T Watanabe, T Shinano, IM Rao

  JOURNAL OF PLANT NUTRITION 29 (1) 35 - 57 0190-4167 2006/01 [Not refereed][Not invited]
   

  As Brachiaria hybrid cv. 'Mulato has adapted to acid soils with extremely low phosphorus (P) contents, its low-P-tolerance mechanisms were investigated and compared with those of wheat ( Triticum aestivum L.) and rice ( Oryza sativa L. cv. 'Kitaake). Among the three plant species, the highest P-use efficiency (PUE) in low-P soil was recorded in the Brachiaria hybrid, which increased remarkably under P-deficiency and soil acidity, while P-deficiency had less effect on the PUE of wheat and rice. As exudation of organic acid anions from roots is considered to be one of the most important mechanisms of adaptation to low-P soil, the role of phospho enol pyruvate carboxylase (PEPC), which is closely related to organic acid metabolism and Pi recycling in C-3 plants, was studied. As expected, the PEPC activity of the Brachiaria hybrid (C-4 plant) leaves was 51- to 129-fold higher than that estimated for wheat and rice (both C-3 plants). PEPC activity in leaves and roots of the Brachiaria hybrid increased up to two-and three-fold, respectively, and decreased the malate-inhibition ratio in leaves in response to P-deficiency. However, PEPC activity and malate-inhibition ratio were less affected in wheat and rice under P-deficiency. The Brachiaria hybrid synthesized higher amounts of organic acids (e.g., oxalate and fumarate) in leaves, especially under P-deficiency. Results from these experiments indicate that PEPC activated in the Brachiaria hybrid under low-P and low-pH conditions may contribute to the plant's greater adaptation to tropical acid soils with P-low availability.
• Different characteristics of nitrogen utilization between lupin and soybean: can lupin utilize organic nitrogen in soils?

  T Watanabe, M Okamoto, S Misawa, M Urayama, M Osaki

  CANADIAN JOURNAL OF BOTANY-REVUE CANADIENNE DE BOTANIQUE 84 (1) 20 - 27 0008-4026 2006/01 [Not refereed][Not invited]
   

  It is well known that lupin forms cluster roots, which help in dissolving insoluble P in soils. In nonleguminous species, cluster roots also appear to contribute to the utilization of organic N in soils. In white lupin (Lupinus albus L.), however, the characteristics of its organic N utilization have not been studied. Therefore, we examined whether white lupin can utilize organic N in soils. Soybean (Glycine max (L.) Merr.), which does not form cluster roots, was used as a control plant. Seedlings of lupin and soybean were cultivated in soils with different N sources (non-N, ammonium sulphate, ammonium sulphate plus cattle farmyard manure, or cattle farmyard manure). The rate of glycine uptake by excised roots was determined in a hydroponic experiment to investigate the ability of lupin and soybean to directly utilize amino acids. Nitrogen accumulation in soybean corresponded to the decrease in inorganic N in the soils. In contrast, N accumulation in lupin was higher than the decrease in inorganic N in the soil, especially with the cattle farmyard manure treatment, indicating that lupin derived more N from an organic N source. Wheat (Triticum aestivum L.) cultivated with lupin in a pot accessed more available N than wheat with soybean or wheat in monoculture, suggesting that lupin roots themselves or the lupin rhizosphere microorganisms were able to decompose organic N in soils. Excised roots of lupin, especially cluster roots, exhibited higher rates of glycine uptake than roots of soybean. In conclusion, lupin decomposed organic N in the rhizosphere and was able to absorb amino acids from decomposition in addition to any inorganic N produced by further microbial decomposition.
• Aluminum accumulation in the roots of Melastoma malabathricum, an aluminum-accumulating plant

  T Watanabe, S Misawa, M Osaki

  CANADIAN JOURNAL OF BOTANY-REVUE CANADIENNE DE BOTANIQUE 83 (11) 1518 - 1522 0008-4026 2005/11 [Not refereed][Not invited]
   

  Generally, plants that have Al levels of at least 1000 mg(.)kg(-1) in their leaves are defined as Al accumulators. These plants are often found in very acid soils in the tropics. The mechanisms of Al uptake in strong Al accumulators are still unclear. In this study, we investigated the characteristics of Al uptake and accumulation in the roots of Melastoma malabathricum L., an Al-accumulating plant that grows in acidic soils in the tropics. Melastoma malabathricum roots hardly absorb any La, possibly because of lower affinity of the root apoplast to La than to Al. Exposure to La did not affect the concentration of citrate in the roots however, application of Al increased the citrate level considerably, corresponding with the amount of Al accumulation in the symplast. 27 Al NMR analysis revealed that Al complexes with oxalate, but not with citrate, in the roots of M. malabathricum. This investigation revealed that oxalate, which occurs constitutively at high concentrations, is a ligand for Al accumulation in both root and shoot tissue, and that citrate, the synthesis of which is induced by Al application, is a ligand mainly used for Al translocation from the roots to the shoots.
• The beneficial effect of aluminium and the role of citrate in Al accumulation in Melastoma malabathricum

  T Watanabe, S Jansen, M Osaki

  NEW PHYTOLOGIST 165 (3) 773 - 780 0028-646X 2005/03 [Not refereed][Not invited]
   

  Here we investigated the beneficial effect of aluminium (Al) on the development of the Al accumulating plant Melastoma malabathricum. Seedlings of M. malabathricum were cultivated in a nutrient solution containing 0.5 mm Al and compared with barley (Hordeum vulgare). In addition, roots of M. malabathricum were divided into one part growing in a nutrient solution, and the other part growing in a calcium solution. Al (0.5 mm) was applied to either solution. Al-induced improvements of the root activity contributed to a growth enhancement in M. malabathricum. Al exposure without nutrients did not increase root growth and A[ accumulation in the leaves. The beneficial effect, however, was induced by the combination of Al and nutrients. We suggest that without nutrients roots are not able to synthesize an adequate amount of citrate that is required for transporting Al to the leaves. High Al levels in the plant tissues and/or an interaction of Al with particular nutrient elements in the apoplast of root cells appear to be essential to exert the beneficial effect of Al.
• Interactive effects of Al, Ca and other cations on root elongation of rice cultivars under low pH

  T Watanabe, K Okada

  ANNALS OF BOTANY 95 (2) 379 - 385 0305-7364 2005/01 [Not refereed][Not invited]
   

  Background and Aims As with other crop species, Al tolerance in rice (Oryza swim) is widely different among cultivars. and the mechanism for tolerance is unknown. The Ca2+-displacement hypothesis. that is. Al displaces Ca2+ from critical sites in the root apoplast, was predicted to be the essential mechanism for causing Al toxicity in rice cultivars. If displacement of Ca is an essential cause of Al toxicity in rice, Al toxicity may Show the same trend as toxicities of elements such as Sr and Ba that are effective in displacing Ca. Methods The interactive effects of Al, Ca, Sr and Ba on root elongation of rice cultivars with different Al tolerance were evaluated in hydroponic culture. Al and Ca accumulation in root tips was also investigated. Key Results and Conclusions Not only Al but also Sr and Ba applications inhibited toot growth of rice cultivars under low Ca conditions. As expected, rice cultivars more tolerant of Sr and Ba were also tolerant of Al (japonica > indica). Although Mg application did not affect Sr or Ba toxicity Mg-2 alleviated Al toxicity to the same level as Ca application. In addition. Ca application decreased the Al content in root tips without displacement. These results suggest that Ca does not have a specific, irreplaceable role in Al toxicity, unlike Sr and Ba toxicities. Alleviation of Al toxicity with increasing concentrations of Ca in rice cultivars is due to increased ionic strength, not due to decreased Al activity. The difference in Al tolerance between indica and japonica cultivars disappear under high ionic strength conditions, suggesting that different electrochemical characteristics of root-tip cells are related to the significant difference in Al tolerance under low ionic strength conditions. (C) 2001 Annals of Botany Company.
• Efeito do aluminio no desenvolvimento e nutricao de Tapirira guianensis Aublet em solucao hidroponica

  Ricardo Miranda de Britez, Carlos Bruno Reissmann, Toshihiro Watanabe, Mitsuru Osaki

  Floresta 32 (2) 171 - 187 2005 [Not refereed][Not invited]
  
• The function of a maize-derived phosphoenolpyruvate carboxylase (PEPC) in phosphorus-deficient transgenic rice

  Hasna Hena Begum, Mitsuru Osaki, Takuro Shinano, Hiroaki Miyatake, Jun Wasaki, Takuya Yamamura, Toshihiro Watanabe

  Soil Science and Plant Nutrition 51 (4) 497 - 506 0038-0768 2005 [Not refereed][Not invited]
   

  Transgenic rice (Oryza sativa L., a C3 plant) lines carrying a complete phosphoenolpyruvate carboxylase (PEPC) gene from maize (a C4 plant) were tested for their performance in terms of organic acid synthesis and organic acid exudation into the rhizosphere under phosphorus (P)-deficient conditions. High PEPC activity increased the fraction of photosynthetically fixed carbon allocated to the organic acid pool, and P deficiency enhanced oxalate exudation from the roots of the transgenic plants. There was no evidence that the transformed PEPC was involved in internal P recycling in the plant. However, the root PEPC activity was positively correlated with the oxalate exudation and negatively correlated with the root P concentration, and a higher root PEPC activity led to a higher oxalate exudation. Thus, it is suggested that C4-PEPC transgenic rice plants had acquired the ability to exude oxalate, which enhanced their capacity to adapt to low P soil conditions.
• The distribution and phylogeny of aluminium accumulating plants in the ericales

  S Jansen, T Watanabe, P Caris, K Geuten, F Lens, N Pyck, E Smets

  PLANT BIOLOGY 6 (4) 498 - 505 1435-8603 2004/07 [Not refereed][Not invited]
   

  The distribution of aluminium (Al) accumulation in the Ericales is surveyed, based on semi-quantitative tests of 114 species and literature data. Al accumulation mainly characterises the families Diapensiaceae, Pentaphylacaceae, Symplocaceae, Ternstroemiaceae, and Theaceae. Al accumulation is consistently present or absent in most families examined, but the character appears to be more variable in a few taxa (e.g., Lecythidaceae, Myrsinaceae). Although the interfamilial relationships within the Ericales require further research, the ability to accumulate high levels of Al appears to show considerable taxonomic significance. While the majority of Al accumulating Ericales includes woody, tropical plants, the feature is remarkably present in several herbaceous Diapensiaceae, which have a distribution in cold to temperate areas. The association of different mycorrhizae types with plant roots is suggested to play a role in the exclusion of high Al levels from the shoot.
• The evolution of aluminium accumulation in angiosperms

  Steven Jansen, Toshihiro Watanabe, Steven Dessein, Elmar Robbrecht, Erik Smets

  The Evolution of Plant Physiology 467 - 479 2004 [Refereed][Not invited]
   

  Aluminum (Al) is ubiquitous in the environment as it is the most abundant metal and the third most common element in the Earth's crust. Al accumulation in plants is not only a very important and ecophysiologically highly interesting phenomenon, but it also provides useful information for systematic purposes at relatively high taxonomic levels. Al accumulation has independently been developed in several plant groups that are not necessarily closely related, but its occurrence is far from being randomly distributed. Its primitive status in the derived groups of the angiosperms is generally confirmed following recent molecular phylogenies. About 93% of all Al accumulators that have been recorded belong to the asteroids and rosids. The primitive status of Al accumulation in angiosperms is suggested on the basis of statistical correlations. Its primitive (plesiomorphic) or derived (apomorphic) nature however, largely depends on the taxonomic level. Further, evolutionary trend of Al accumulation is complicated by the occurrence of numerous reversals (or losses) and parallel origins. Alternatively, the low incidence of Al accumulators in derived groups might also be correlated with their frequent herbaceous habit. Al accumulation is considered to be a process that depends partly on the influence of heredity and partly on ecological influence. Among ecological factors, the most important factor is soil acidity. The soil pH comprises the most important factor in Al uptake because the solubility and bioavailability of Al increases with decreasing pH. © 2004 Elsevier Ltd. All rights reserved.
• Growth responses of cereal crops to organic nitrogen in the field

  M Okamoto, K Okada, T Watanabe, N Ae

  SOIL SCIENCE AND PLANT NUTRITION 49 (3) 445 - 452 0038-0768 2003/06 [Not refereed][Not invited]
   

  Growth responses of rice (Oryza sativa), sorghum (Sorghum bicolor), pearl millet (Pennisetum glaucum), and maize (Zea mays) to applications of the organic form of nitrogen (N) were examined under field conditions in 2000-2001. Nitrogen was applied at the rate of 15 g m(-2) in the form of inorganic N (IN, urea) or organic N (ON, a mixture of rice bran and straw). Organic N application had no significant effect on the concentration of soil inorganic N (ammonium and nitrate), but increased the concentration of neutral phosphate-buffer-extractable organic N in the soil at the early growth stage. The shoot dry weight and N uptake of crops in the ON treatment were similar to those in the IN treatment for pearl millet and maize, but were significantly higher than in the IN treatment for rice and sorghum at the early growth stage. The higher proportion of organic N in the xylem sap of rice and sorghum in the ON treatment compared with the IN treatment also suggests that these two crops could take up the increased amount of soil organic N more efficiently than could maize, for which there was no difference between the treatments. Although pearl millet showed similar results to those of rice and sorghum in xylem sap analysis, the utilization of absorbed organic N was considered inefficient because of the adequate N status in the plant, based on the high concentration of nitrate N in the plant tissues. This is the first study to demonstrate the possibility that sorghum can utilize organic N in the soil more efficiently than can pearl millet. The possible forms of organic N in the soil absorbed by crop roots, such as protein and 8,000-9,000 Da molecular weight compounds, are discussed.
• A comparative study of metal levels in leaves of some Al-accumulating Rubiaceae

  S Jansen, T Watanabe, S Dessein, E Smets, E Robbrecht

  ANNALS OF BOTANY 91 (6) 657 - 663 0305-7364 2003/05 [Not refereed][Not invited]
   

  Concentrations of Al, Si, Fe, Mn, Cu and Ca were analysed in leaves of. ten Rubiacea. e species, most of which are At accumulators, and these were compared with concentrations in one species of Melastomataceae. Quantitative data confirmed the distribution of Al accumulation as previously determined by semi-quantitative tests, and suggest that there is an apparent congruency between the shoot Al concentration and the number of accumulators within a certain genus or tribe. Al accumulators within the Rubiaceae are most characteristic of the Rubioideae subfamily, although a second origin is likely in at least a few members of the tribes Vanguerieae and Alberteae. While the leaf Si concentration in Melastomata malabathricum L. (Melastomataceae) was negligible, all Rubiaceae studied showed relatively high Si levels (mostly >3000 mg kg(-1)). It is hypothesized that an Al-Si complex is formed in the shoot tissues of Al-accumulating Rubiaceae and that this may contribute to Al detoxification. However, the Si : Al mote ratio tended to differ widely among species. There was no significant correlation between Al and the other metals analysed. A remarkably high Mn concentration was found in Coptosapelta olaciformis Elm. (C) 2003 Annals of Botany Company.
• Breeding Wheat for Zinc Efficiency Improvement in Semi-arid Climate-A Review

  Rishi Kumar BEHL, Mitsuru OSAKI, Jun WASAKI, Toshihiro WATANABE, Takuro SHINANO

  Tropics 日本熱帯生態学会 12 (4) 295 - 312 0917-415X 2003 [Not refereed][Not invited]
  
• Nutritional characteristics of the leaves of native plants growing in adverse soils of humid tropical lowlands

  M Osaki, T Watanabe, T Ishizawa, C Nilnond, T Nuyim, T Shinano, M Urayama, SJ Tuah

  PLANT FOODS FOR HUMAN NUTRITION 58 (2) 93 - 115 0921-9668 2003 [Not refereed][Not invited]
   

  Acid sulfate, peat, sandy podzolic, and saline soils are widely distributed in the lowlands of Thailand and Malaysia. The nutrient concentrations in the leaves of plants grown in these type of soils were studied with the aim of developing a nutritional strategy for adapting to such problem soils. In sago and oil palms that were well-adapted to peat soil, the N, P, and K concentrations were the same in the mature leaves, while the Ca, Mg, Na, and Fe concentrations were higher in the mature leaves of the oil palm than of the sago palm. Melastoma malabathricum and Melaleuca cajuputi plants that were well-adapted to low pH soils, peat, and acid sulfate soils were also studied. It was observed that a high amount of Al accumulated in the M. marabathricum leaves, while Al did not accumulate in M. cajuputi leaves. M. cajuputi plants accumulated large amounts of Na in their leaves or stems regardless of the exchangeable Na concentration in the soil, while M. malabathricum that was growing in saline-affected soils excluded Na. Positive relationships between macronutrients were recognized between P and N, between K and N, and between P and K. Al showed antagonistic relationships with P, K, Ca, Mg, Fe, Zn, Cu, and Na. Na also showed antagonistic relationships with P, K, Zn, Mn, Cu, and Al. Fe showed weak antagonistic relationships with Zn, Mn, Cu, and Al.
• Mineral characteristics of the leaves of 166 plant species with different phylogeny in the temperate region

  M Osaki, S Yamada, T Ishizawa, T Watanabe, T Shinano, SJ Tuah, M Urayama

  PLANT FOODS FOR HUMAN NUTRITION 58 (2) 139 - 152 0921-9668 2003 [Not refereed][Not invited]
   

  The P-N regression coefficient was moderate in Magnoliales, Coniferopsidae, Pteridophyta, and Asterids, but very high in Caryophyllids, and very low in Rosids. The K-N regression coefficient in trees remained constant regardless of evolution, and that in grasses was high except for Rosids compared with that in trees. The coefficient was very high in Caryophyllids and was very low in Rosids. The N-Ca and N-Mg relationship was not estimated at all, suggesting that the mechanism of Ca and Mg accumulation was completely different from that of N related accumulation. The Zn and Cu concentrations were related to the N concentration. The Al concentration in leaves was negatively correlated with the N, P, K, Ca, Mg, Na, Cu, Zn, Mn, and Fe concentrations, while the N, P, K, and Mn concentrations in leaves increased slightly with the increase of Al concentration in the high Al concentration. The Na concentration in leaves related negatively to the P, Ca, Cu, Zn, Mn and Al concentration range. Thus, it was demonstrated that most of the minerals in leaves accumulate negatively Al and Na indicating that there are antagonistic mechanisms for mineral accumulation in leaves among Al or Na and other mineral elements.
• Mineral characteristics of leaves of plants from different phylogeny grown in various soil types in the temperate region

  M Osaki, S Yamada, T Ishizawa, T Watanabe, T Shinano, M Urayama

  PLANT FOODS FOR HUMAN NUTRITION 58 (2) 117 - 137 0921-9668 2003 [Not refereed][Not invited]
   

  The objective of this research was to analyze selected minerals in leaves of plants, belonging to 166 species growing in alluvial, low pH, brown forest and serpentine soils. Mineral characteristics of the soils involved were also determined. For the macronutrients, in trees grown in alluvial soil, N, P, Ca, and Mg concentrations of leaves were higher in recently evolved plants than in plants with a longer period of evolution; K concentration remained constant regardless of evolution. In grasses grown in alluvial soil, it was difficult to detect the general tendency of mineral concentration. N, P, and K concentrations in alluvial soil were closely related to those in low pH and serpentine soils. Ca concentration in alluvial soil was lower than that in low pH and serpentine soils. Mg concentration in alluvial soils was higher than that in low pH soils, while lower than that in serpentine soil. Therefore, N, P, and K accumulated according to the plant characteristics for these elements, while Ca and Mg accumulation was strongly affected by the soil properties. For the micronutrients, in trees, Fe and Mn remained constant regardless of evolution; Zn concentration was lower in recently-evolved plants than in plants with a longer period of evolution. In grasses, Fe, Mn, and Zn concentrations in Caryophyllids were high. Except for Caryophyllids, Fe and Cu concentrations remained constant, Mn concentration decreased with evolution, Zn concentration was higher in recently-evolved plants than in plants with a longer period of evolution.
• The relationship between aluminium and silicon accumulation in leaves of Faramea marginata (Rubiaceae)

  RM Britez, T Watanabe, S Jansen, CB Reissmann, M Osaki

  NEW PHYTOLOGIST 156 (3) 437 - 444 0028-646X 2002/12 [Not refereed][Not invited]
   

  The relationship between high aluminium (Al) and silicon (Si) levels in Faramea marginata was investigated and the hypothesis tested that the coexisting accumulation of these elements is associated. Mineral concentrations of Al, Si and calcium (Ca) were analysed in 30 samples by atomic absorption spectrophotometry and the spectrophotometric molybdenum blue method. Extraction patterns of Al and Si from leaves were compared with Melastoma malabathricum, rice (Oryza sativa), aluminium silicate, and silicon dioxide. The localization of Al and Si was studied using pyrocatechol violet staining of sections and fluorescent X-ray analytical microscopy. A positive correlation occurred between the Al and Si levels and both elements showed a similar distribution in leaf and stem tissues. The Al and Si elution patterns were similar to those of aluminium silicate. These results suggest the formation of an Al-Si complex in the shoot tissues of F. marginata, which may substantially contribute to the internal detoxification of Al.
• Genotypic variability in phosphorus solubilizing activity of root exudates by pigeonpea grown in low-nutrient environments

  S Ishikawa, JJ Adu-Gyamfi, T Nakamura, T Yoshihara, T Watanabe, T Wagatsuma

  PLANT AND SOIL 245 (1) 71 - 81 0032-079X 2002/08 [Not refereed][Not invited]
   

  A pot experiment confirmed that pigeonpea could efficiently utilize various sources of phosphorus (P) (aluminium phosphate, iron phosphate and apatite), irrespective of genotype. A qualitative assay method for iron (Fe)- P solubilizing activity showed that root exudates collected from P-deficient pigeonpea contained Fe-P solubilizing substances and that they were released mainly from root tips. Citric, malic, malonic, succinic and piscidic acids were identified in root exudates. Citric and piscidic acids release from roots was increased by low-P treatment in all the genotypes tested. The release rates of citric and piscidic acids were affected by the P concentration of shoots rather than that of roots. The pigeonpea roots released approximately 5-100 times more piscidic acid than citric acid depending on P stress status, plant age and genotype. When organic acids were added to Alfisols, citric acid was most capable of mobilizing P from the soil, followed by piscidic acid and malic acid. No correlation was found between genotypic variability in the release rates of citric and piscidic acids from the roots under low-P treatment at hydroponic culture and in the growth and P uptake of plants on Alfisols. Although citric and piscidic acids released from pigeonpea roots may play a partial role in solubilizing unavailable insoluble P in soils, the releases were thought to be an unsatisfactory strategy for explaining genotypic variation in low P availability of pigeonpea.
• Role of organic acids in aluminum accumulation and plant growth in Melastoma malabathricum

  T Watanabe, M Osaki

  TREE PHYSIOLOGY 22 (11) 785 - 792 0829-318X 2002/08 [Not refereed][Not invited]
   

  Melastoma malabathricum L. (melastoma) is an Al-accumulating woody plant that grows in tropical Southeast Asia in acid soils with high aluminum (Al) concentrations and low nutrient concentrations. Because oxalate serves as a ligand for Al accumulation in melastoma leaves and citrate is the ligand associated with Al translocation from roots to shoots, we investigated the role of organic acids in the adaptation of melastoma to growth on these soils. Phosphorus starvation increased oxalate concentration in the rhizosphere, enabling melastoma to solubilize insoluble aluminum phosphate in the rhizosphere. Increased availability of P and Al in the rhizosphere enhanced growth. In the xylem sap, the concentration of citrate increased with increasing Al concentration. In contrast, the concentrations of malate, succinate and alpha-ketoglutarate in the xylem sap decreased with increasing Al concentration, suggesting that tricarboxylic acid cycle enzymes were affected by Al treatment.
• Aluminium accumulation in leaves of 127 species in Melastomataceae, with comments on the order Myrtales

  S Jansen, T Watanabe, E Smets

  ANNALS OF BOTANY 90 (1) 53 - 64 0305-7364 2002/07 [Not refereed][Not invited]
   

  The distribution and systematic significance of aluminium accumulation is surveyed based on semi-quantitative tests of 166 species, representing all tribes and subfamilies of the Melastomataceae as well as a few members of related families within the Myrtales. The character is strongly present in nearly all members of the Memecylaceae and in most primitive taxa of the Melastomataceae, while non-accumulating taxa are widespread in the more derived tribes of the Melastomataceae. The variable distribution of Al accumulation in advanced clades of the latter family is probably associated with the tendency to herbaceousness, although it is unclear whether the more herbaceous representatives have developed more specialized Al-response mechanisms that may exclude high Al levels from the shoot. It is hypothesized that Al accumulation is symplesiomorphic for Melastomataceae and Memecylaceae, and that the feature characterizes the most primitive families in the Myrtales. Indeed, Al accumulation is also characteristic of Crpteroniaceae, Rhynchocalycaceae and Vochysiaceae. Crypteroniaceae and Rhynchocalycaceae probably take a basal position in a sister clade of the Memecylaceae and Melastomataceae, while Al accumulation suggests a basal position for Vochysiaceae in the Myrtaceae clade. (C) 2002 Annals of Botany Company.
• Mechanisms of adaptation to high aluminum condition in native plant species growing in acid soils: A review

  T Watanabe, M Osaki

  COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 33 (7-8) 1247 - 1260 0010-3624 2002 [Not refereed][Not invited]
   

  Various studies of the mechanisms of aluminum (Al) tolerance in crop plants have been conducted to improve crop productivity in acid soils. However, many native plant species vigorously grow in acid soils. These species have adapted well to high levels of Al in the medium. The mechanisms of this adaptation can be separated into Al exclusion and internal Al inactivation. In general. plant species that have developed mechanisms of the former type are called "Al excluders," and those that have developed mechanisms of the latter type are called "Al accumulators." Mechanisms of Al exclusion in excluder species have not been completely elucidated, and may involve some strong mechanisms in addition to the exudation of organic acid from roots. Al accumulator species are supposed to create an Al-ligand (mainly organic acids) complex for translocation from roots to shoots, and for accumulation in the leaves. Interestingly, the ligand of Al for translocation often differs from that for storage in the leaves. In addition, Al accumulator species seem to prevent the toxic effect of Al on the metabolism in leaves by means of isolating the Al in sites that are insensitive to Al (e.g., epidermal cells or vacuoles). Growth in some native plant species that have adapted to acid soils is enhanced by Al application. This Al-induced growth enhancement is considered to be caused by Al-induced stimulation of nutrient uptake in Al excluders (nonaccumulators), and by physiological effects of Al itself in addition to the stimulation of nutrient uptake in accumulators. Elucidation of these mechanisms of adaptation to high levels of Al in medium will be useful for improved production of Al-tolerant crop cultivars and rehabilitation of forest areas.
• Influence of aluminum and phosphorus on growth and xylem sap composition in Melastoma malabathricum L.

  T Watanabe, M Osaki

  PLANT AND SOIL 237 (1) 63 - 70 0032-079X 2001/11 [Not refereed][Not invited]
   

  Melastoma (Melastoma malabathricum L.) is an aluminum-accumulating woody plant that accumulates more than 10 000 mg kg(-1) of aluminum (Al) in mature leaves. The influence of Al and phosphorus (P) applications on plant growth and xylem sap was examined in the present study in order to elucidate the interaction between Al-induced growth enhancement and P nutrition, and to determine the form of Al for translocation from roots to shoots. Although the Al application significantly increased the growth of Melastoma seedlings with the high P pre-treatment, and P concentrations in the leaves and Pi concentrations in the xylem sap regardless of the P pre-treatment, we could not come to the conclusion that a primary cause of the Al-induced growth enhancement in Melastoma is the stimulation of P uptake. The degree of Al-induced growth enhancement corresponded not with the P concentrations but with the Al concentrations in the plant tissue, suggesting that the Al-induced growth enhancement in Melastoma is primarily caused by Al itself in the plant tissue rather than by the stimulation of P uptake. Through the analysis of organic acids and Al in the xylem sap and plant tissue, the form of Al for translocation from roots to shoots was shown to be an Al-citrate complex that was transformed into Al-oxalate complex for Al storage in the leaves. In addition, the xylem sap of Melastoma seedlings grown in the absence of Al contained higher concentrations of malate. In the presence of Al, however, higher concentrations of citrate were found, indicating that Melastoma changes its organic acid metabolism in the presence or absence of Al; more specifically, it increases the synthesis of citrate.
• Al uptake kinetics in roots of Melastoma malabathricum L. - an Al accumulator plant

  T Watanabe, M Osaki, T Tadano

  PLANT AND SOIL 231 (2) 283 - 291 0032-079X 2001/04 [Not refereed][Not invited]
   

  The mechanism of Al uptake in melastoma (Melastoma malabathricum L.), which accumulates Al in excess of 10 000 mg kg(-1) in its leaves and roots, was investigated. Al uptake kinetics in excised melastoma roots showed a biphasic pattern, with an initial rapid phase followed by a slow phase. It was indicated that Al uptake in the excised roots occurs mostly through passive accumulation in the apoplast. On the other hand, Al uptake rate in roots of whole melastoma plant was almost double that in excised roots. The difference of Al uptake rate between excised roots and whole plant seems to be due to transpiration-depended Al uptake. Results from a long-term experiment showed that different characteristics of Al accumulation between melastoma and barley was caused by the difference in capacity to retain Al in root symplast, rather than by the difference in uptake rate into symplast. Concentrations of oxalate in root symplastic and apoplastic fractions, and total oxalate in shoots and roots, did not change greatly with time of Al exposure compared to Al concentration, although oxalate is considered as a main Al ligand in tissue of melastoma. On the other hand, oxalate exudation to root apoplast was induced within 24 h of Al exposure; the role of such exudation was discussed.
• Comparison of aluminum tolerance and phosphate absorption between rape (Brassica napus L.) and tomato (Lycopersicum esculentum Mill.) in relation to organic acid exudation

  HM Luo, T Watanabe, T Shinano, T Tadano

  SOIL SCIENCE AND PLANT NUTRITION 45 (4) 897 - 907 0038-0768 1999/12 [Not refereed][Not invited]
   

  Aluminum (Al) tolerance and phosphate absorption in rape and tomato were compared under water culture and field conditions. The relative growth rate in the Al treatment compared with -Al treatment was similar in the two crops under water culture conditions, while under field conditions, the growth rate was 2- to 3-fold higher in rape than in tomato in spite of the higher Al concentration in the soil solution than in the culture solution. The relative amount of phosphate absorbed in the Al treatment compared with -Al was not appreciably different between rape and tomato under water culture conditions, while under field conditions, it was 3- to 6-fold larger in rape than in tomato. The exudation rate of citric acid by roots was much higher in rape than in tomato. The plant growth, root elongation, and amount of phosphate absorbed in rape were inhibited in the 150 mu M Al in the culture solution. However, the inhibition was alleviated by the addition of 200 mu M citric acid or 500 mu M malic acid. The P concentration in the culture solution decreased by the presence of Al as aluminum phosphate. However, addition of citric and malic acids increased the amount of phosphate released from the precipitated aluminum phosphate. In conclusion, one of the mechanisms for the higher Al tolerance and larger phosphate absorption in rape than in tomato under field conditions was ascribed to the higher concentration of exuded citric acid by Al in the rhizosphere. It was suggested that the exudation of citric acid might contribute to the detoxification of Al and to the increase phosphate availability in the rhizosphere in rape.
• Effects of nitrogen source and aluminum on growth of tropical tree seedlings adapted to low pH soils

  T Watanabe, M Osaki, T Tadano

  SOIL SCIENCE AND PLANT NUTRITION 44 (4) 655 - 666 0038-0768 1998/12 [Not refereed][Not invited]
   

  The effects of N-source and Al on the growth of seedlings of Melastoma malabathricum, Acacia mangium, and Melaleuca cajuputi, which are tropical woody plants and are very tolerant to Al, and barley (Hordeum vulgare), which is a typical Al-sensitive plant, were investigated. The Al and N treatments consisted of the application of either 0 or 0.5 mM Al, and 2 mM NH4+ or NO3-, respectively. Growth of the tropical plants was enhanced by Al and NH4 application. In all the plant species, the pH of the culture solution decreased and the concentrations of soluble Al and P increased with the +NH4 treatment, which positively affected the growth of the tropical plant species. Excised roots of M. malabathricum dissolved insoluble Al with NH4 application and absorbed Al mainly from root tips. Al did not affect the leaf N concentration except in the case of barley. Roots of M. cajuputi exuded a large amount of citrate, which slightly increased by the +Al treatment. In A. mangium, the reactivity of soluble Al to PCV (pyrocatecholviolet) decreased in the culture solution of the +Al+NH4 treatment and Al concentration of roots in this treatment was very low. Roots of M. malabathricum released H+ along with Al uptake as well as NH4+ uptake. It is concluded that Al and NH4+ exert beneficial effects on the growth of tropical tree seedlings.
• Distribution and chemical speciation of aluminum in the Al accumulator plant, Melastoma malabathricum L.

  T Watanabe, M Osaki, T Yoshihara, T Tadano

  PLANT AND SOIL 201 (2) 165 - 173 0032-079X 1998/04 [Not refereed][Not invited]
   

  The Al accumulation mechanisms in an Al accumulator plant, Melastoma malabathricum L. (Melastoma), was investigated. Al was located in the upper epidermal cells and also distributed in mesophyll cells in leaf sections. In root sections, Al was found in all the root tissues, particularly in the epidermis and endodermis. Al concentrations in young leaves, mature leaves, old leaves, and roots were 8.0, 9.2, 14.4, and 10.1 mg g(-1), respectively. Approximately 45% of total Al in oldest leaves, and approximately 60% of total Al in leaves of other positions and roots were extracted in Tris-HCl buffer (pH 7.0). Since Al in the residual parts was mostly dissolved in hot 0.5 M H(2)SO(4) containing 2% cetyl trimethylammonium bromide, residual Al seemed to consist mainly of monomeric Al and Al bound to pectic substances and hemicellulose. Al in the Tris-HCl extract consisted of non-monomeric Al (complexed form). Oxalate concentration in the Tris-HCl extract in leaves was significantly higher in the +Al treatment than in the -Al treatment and there was a positive correlation between the Al concentration and oxalate concentration. (27)Al NMR spectrum of fresh leaves indicated the presence in the order of monomeric Al, Al-oxalate, Al-(oxalate)(2), and Al-(oxalate)(3) in intact leaves.
• Nutritional characteristics in leaves of native plants grown in acid sulfate, peat, sandy podzolic, and saline soils distributed in Peninsular Thailand

  M Osaki, T Watanabe, T Ishizawa, C Nilnond, T Nuyim, C Sittibush, T Tadano

  PLANT AND SOIL 201 (2) 175 - 182 0032-079X 1998/04 [Refereed][Not invited]
   

  Acid sulfate soils, peat soils, sandy podzolic, and saline soils are widely distributed in Peninsular Thailand. Native plants adapted to such problem soils have grown well, and showed no symptom of mineral deficiency or toxicity. Dominant plants growing in low pH soils (acid sulfate and peat) were Melastoma marabathricum and Melaleuca cajuputi. Since M. marabathricum accumulated a huge amount of aluminum (Al) in leaves, especially in new growing leaves, it can be designated an Al accumulator plant. While M. cajuputi did not accumulate Al in shoot, it can be designated an Al excluder plant. Both plant species adapted well to low pH soils, though a different strategy was used for Al. On the other hand, in acid sulfate and peat soils, M. cajuputi, Panicum repens, Cyperus haspan, and Ischaemum aristatum accumulated large amounts of Na in the leaves (or shoots), even in soil with low exchangeable Na concentration. Thus, when growing in the presence of high Al and Na concentration in soils, plant species have developed two opposite strategies: (1) Al or Na accumulation in the leaf and (2) Al or Na exclusion from the leaf. Al concentration in leaves had a negative relationship with the other mineral nutrients except for N and Mn, and Na concentration in leaves also had a negative relationship with P, Zn, Mn, Cu, and Al. Consequently, Al and Na accumulator plants are characterized by their exclusion of other minerals from their leaves.
• Nutritional characteristics of sage palm and oil palm in tropical peat soil

  M Matsumoto, M Osaki, T Nuyim, A Jongskul, P Eam-on, Y Kitaya, M Urayama, T Watanabe, T Kawamukai, T Nakamura, C Nilnond, T Shinano, T Tadano

  JOURNAL OF PLANT NUTRITION 21 (9) 1819 - 1841 0190-4167 1998 [Not refereed][Not invited]
   

  To make clear the nutritional characteristics of sago palm (Metroxylon sagu Rottb.) and oil palm (Elaeis guineensin Jacq.) grown in tropical peat soil, minerals concentration, organic compounds concentration, and photosynthetic rate were estimated, and the obtained results were as follows. Since, the nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and sodium (Na) concentration in mature leaves and trunk were higher in the oil palm than in the sage palm, but potassium (K) concentration was higher in the sage palm than in the oil palm, the minerals (especially N, P, Ca, and Mg) requirement for the oil palm were higher than in the sage palm. This indicates that the sage palm will adapt better than the oil palm to soils with poor nutrients. The manganese (Mn) and zinc (Zn) concentration in leaves of the sage palm and Ca and aluminum (Al) concentration in leaves of the oil palm increased with the increase of aging, indicating that those elements are eliminated fi om plants through leaf senescence. Tn the sage palm, the N and P distribution ratio to leaves remained almost constant during growth, indicating that N and P were predominantly distributed to leaves for maintaining leaf function. The photosynthetic rate [mu mole carbon dioxide (CO2) m(-2) LA sec(-1)] at light saturation was lower in the sage palm (5.8) and oil palm (10.0) than in wheat(25.4). As leaf longevity of sage and oil palms was longer (about 12 times) than that of wheat (Triticum aevstium L.), and the minerals concentration and photosynthetic rate remained constant for a long duration of growth, the cumulative carbon (C) accumulation per unit dry weight (photosynthetic rate x leaf longevity) in the individual leaf is assumed to be equal or greater than that of wheat. The photosynthetic ability of sago and oil palms leaves is very important for understanding why sage and oil palms have high productivity in spite of a low nutrient environment.
• Aluminum-induced growth stimulation in relation to calcium, magnesium, and silicate nutrition in Melastoma malabathricum L.

  T Watanabe, M Osaki, T Tadano

  SOIL SCIENCE AND PLANT NUTRITION 43 (4) 827 - 837 0038-0768 1997/12 [Not refereed][Not invited]
   

  Effects of Al, Ca, Mg, and Si on the growth and mineral accumulation of ill. malabathricum (Melastoma malabathricum L.), which is an Al accumulator plant, were investigated using the water culture method. Rice (Oryza sativa L.) and barley (Hordeum vulgare L.) were used as control plants. After AZ application, growth was inhibited in barley, but stimulated in M. malabathricum and rice. The growth of M. malabathricum was not reduced by very low Ca and Mg concentrations (0.1 mM Ca and 0.05 mM Mg). However, it was depressed in the absence of Ca. Ca and Rag contents somewhat decreased by Al application, which was most evident in young leaves and roots. M. malabathricum accumulated more than 10,000 mg kg(-1) Al in mature leaves, and more than 7,000 mg kg(-1) even in the youngest leaf. Al content in leaves of M. malabathricum did not decrease by the Ca or Mg application, but slightly decreased by in the absence of Ca. Although Si is a strong ligand of Al in solution, in M. malabathricum, Si application hardly affected the growth, Al accumulation and nutrient uptake.
• Beneficial effect of aluminum on growth of plants adapted to low pH soils

  M Osaki, T Watanabe, T Tadano

  SOIL SCIENCE AND PLANT NUTRITION 43 (3) 551 - 563 0038-0768 1997/09 [Not refereed][Not invited]
   

  Plants in which growth was reduced by low and high Al applications were designated as Al-sensitive plant (Hordeum vulgare) and Al-medium tolerant plants (Leucaena leucocephala, Ischaemum barbatum, Stylosanthes guianensis, and Fagopyrum esculentum), respectively, while plants in which growth was not affected or was stimulated by Al application were designated as Al-tolerant plant (Brachiaria ruziziensis) and Al-stimulated plants (Melastoma malabathricum, Melaleuca cajuputi, Acacia mangium, Hydrangea macrophylla, Vaccinium macrocarpon, Polygonum sachalinense, and Oryza sativa), respectively. Plants tolerant to or stimulated by Al were further classified based on the criteria of Al accumulation: 1) Al-excluders such as M. cajuputi, A. mangium, L. leucocephala, I. barbatum, S. guianensis, and O. sativa, 2) Al root-accumulators such as V. macrocarpon, B. ruziziensis, and P. sachalinense, and 3) Al-accumulators such as M. malabathricum, H. macrophylla, and F. esculentum. The growth and N, P, and Ii uptake in M. malabathricum, iii. cajuputi, A. mangium, L. leucocephala, H. macrophylla, V. macrocarpon, I. barbatum, P. sachalinense, F. esculentum, and O. sativa were stimulated by Al application, especially P uptake, while in H. vulgare (Al-sensitive plant) they were reduced by Al application. Ca and Mg uptake of many plants was inhibited by Al application, while that of some plants adapted to low pH soils was not affected at all (Ca and Rig: M. cajuputi, H. macrophylla, V. macrocarpon, I. barbatum, and S. guianensis; Mg: B. ruziziensis and P. sachalinense). In M. malabathricum, the relationship between Al and Ca (or Mg) was antagonistic because the Ca and Mg contents decreased by Al application even though dry matter, N, P, and K accumulation was stimulated by Al application. Plants adapted to low pH soils grew poorly in the no-Al treatment. Since the effect of the pH on plant growth was less conspicuous than that of Al, growth stimulation by Al application was ascribed not only to the alleviation of H+ toxicity but also to the increase of root activity such as P uptake.
• イネおよびオオムギにおける耐塩性機構の差異

  中村 卓司, 大崎 満, 安藤 理子, 但野 利秋

  日本土壌肥料学雑誌 一般社団法人 日本土壌肥料学会 67 (4) 459 - 459 0029-0610 1996

Books etc

• Aluminum Stress Adaptation in Plants

  Wagatsuma T, Maejima E, Watanabe T, Khan MSH, Ishikawa S (Joint workSignificant Role of the Plasma Membrane Lipid Bilayers in Aluminum Tolerance of Plants)
  Springer 2015 99-124
• 園芸学の基礎

  Toshihiro Watanabe (Joint work養分吸収の生理)
  農文協 2012 109-118
• Principles, Application and Assessment in Soil Science

  Watanabe T, Khan MSH, Rao IM, Wasaki J, Shinano T, Ishitani M, Koyama H, Ishikawa S, Tawaraya K, Nanamori N, Ueki N, Wagatsuma T (Joint workPhysiological and Biochemical Mechanisms of Plant Adaptation to Low-Fertility Acid Soils of the Tropics: The Case of Brachiariagrasses)
  IntechOpen 2011
• Genetics, Genomics, and Breeding of Soybean

  Nakamura T, Okazaki K, Benkeblia N, Wasaki J, Watanabe T, Matsuura H, Uchimiya H, Komatsu S, Shinano T (Joint workMetabolomics approach in soybean)
  CRC Press 2010 313-330
• 北海道農業と土壌肥料2010

  櫻井道彦, 渡部敏裕 (Joint work土壌有機物の動態解析法)
  北農会 2010 253-255
• The Evolution of Plant Physiology. From whole plant to ecosystems

  Jansen S, Watanabe T, Dessein S, Robbrecht E, Smets E (Joint workThe evolution of aluminium accumulation in angiosperms)
  Elsevier Academic Press 2004 467-479
• Sustainable Agriculture for Food, Energy, and Industry

  Osaki M, Matsumoto M, Watanabe T, Kawamukai T, Shinano T, Nuyim T, Nilnond C, Tadano T (Joint workStrategies for adaptation of plants grown in adverse soils)
  James & James Ltd. 1998 537-546

Conference Activities & Talks

• Response of plants adapted in low pH soils to aluminum  [Not invited]

  Watanabe T, Osaki M, Tadano T

  XIII International Plant Nutrition Colloquium  Tokyo
• Growth stimulation effect of aluminum on Al accumulator plant - Melastoma malabathricum  [Not invited]

  Watanabe T, Osaki M, Damdinsuren T, Tadano T

  International Workshop on New Concepts of Plant Nutrient Acquisition  Tsukuba
• Effect of aluminum on growth of melastoma (Melastoma malabathricum L.)  [Not invited]

  Watanabe T, Osaki M, Tadano T

  International Symposium on Impact of Potential Tolerance of Plants on the Increased Productivity under Aluminum Stress  Okayama
• Study on aluminum resistance in relation to organic acid anion exudation from roots of PEPC transgenic rice plants  [Not invited]

  Osaki M, Nursymsi D, Begum HH, Watanabe T

  XIV International Plant Nutrition Colloquium  Germany
• A physiological study of Melastoma malabathricum, an aluminium accumulating woody plant  [Not invited]

  Watanabe T, Jansen S, Osaki M

  Fifth Keele Meeting on Aluminium. Aluminium in Life: from acid rain to Alzheimer's disease,  U.K.
• The distribution, ecology and evolution of aluminium accumulation in flowering plants  [Not invited]

  Jansen S, Watanabe T, Smets E

  Fifth Keele Meeting on Aluminium. Aluminium in Life: from acid rain to Alzheimer's disease,  U.K.
• The relationship between growth and Al accumulation in Melastoma malabathricum L., an Al accumulator growing in tropical acid soils  [Not invited]

  Watanabe T, Jansen S, Osaki M

  6th International Symposium on Plant-Soil Interactions at Low pH  Sendai
• Variation in leaf mineral concentrations of terrestrial plants in Japan  [Not invited]

  Osaki M, Watanabe T, Tuah SJ, Takada J, Satake K, Takamatsu T, Jansen S

  First International Workshop on Plant Ionomics  China
• Possibility of rhizosphere regulation for phytoremediation and ecosystem health  [Not invited]

  Osaki M, Matsuda M, Afrida, Hoshina S, Tamai Y, Purnomo E, Watanabe T, Wasaki J, Shinano T

  International Symposium on Phytoremediation and Ecosystem Health  China
• Different capabilities of organic nitrogen uptake in cereal crops  [Not invited]

  Okamoto M, Okada K, Watanabe T, Ae N, Osaki M

  XV International Plant Nutrition Colloquium  China
• The characteristics of aluminum uptake in roots of Melastoma malabathricum, an aluminum accumulating plant  [Not invited]

  Watanabe T, Misawa S, Hiradate S, Jansen S, Osaki M

  XV International Plant Nutrition Colloquium  China
• Mechanism underlying improved plant growth in acidic soil by arbuscular mycorrhizal symbiosis  [Not invited]

  Inaba S, Watanabe T, Osaki M, Ezawa T

  Second International Rhizosphere Conference  France
• Different characteristics of root mucilage in aluminium adsorption between Melastoma malabathricum and Zea mays  [Not invited]

  Watanabe T, Misawa S, Hiradate S, Osaki M

  Second International Rhizosphere Conference  France
• Difference in acquisition of soil organic nitrogen between pak-choi and tomato  [Not invited]

  Watanabe T, Enomoto T, Okamoto M, Sakurai M, Takuro S, Osaki M

  International Plant Nutrition Colloquium XVI  U.S.A.
• Role of thiol compounds in arsenic tolerance in Pteris vittata  [Not invited]

  Watanabe T, Yuki S, Senoura T, Hiradate S, Wasaki J, Osaki M

  International Plant Nutrition Colloquium XVI  U.S.A.
• Decrease of cadmium accumulation in crops by zero-valent iron  [Not invited]

  Watanabe T, Nakamura T, Murata Y, Sakai Y, Osaki M

  International Plant Nutrition Colloquium XVI  U.S.A.
• Possible reasons why aluminum is a beneficial element for Melastoma malabathricum, an aluminum accumulator  [Not invited]

  Watanabe T, Osaki M

  International Plant Nutrition Colloquium XVI  U.S.A.
• Rice root growth with increasing in plant hormone and allantoin by inosine in nutrient solution  [Not invited]

  Tokuhisa D, Okazaki K, Shinano T, Watanabe T, Yokoi D, Osaki M

  International Plant Nutrition Colloquium XVI  U.S.A.
• Comprehensive analysis of mineral elements in different plant species under N, P and K deficiencies  [Not invited]

  Okada R, Watanabe T, Urayama M, Osaki M

  Rhizosphere 3 International Conference  Australia
• Plasma membrane sterols and the related gene in root-tip portion as key components for aluminium tolerance of varieties of plants species, cultivars, lines and mutants  [Not invited]

  Wagatsuma T, Watanabe T, Khan MSH, Sekimoto H, Yokota T, Nakano T, Toyomasu T, Tawaraya K, Koyama H

  Rhizosphere 3 International Conference  Australia
• Uptake and distribution of sulphur in Pteris vittata grown with arsenic  [Not invited]

  Watanabe T, Kouho R, Onodera T, Kitajima N, Sakamoto N, Shinano T, Yurimoto H, Osaki M

  Rhizosphere 3 International Conference  Australia
• Nano LC-MS analysis on root secreting  [Not invited]

  Shinano T, Yoshimura T, Komatsu S, Tokutake S, Kong FJ, Watanabe T, Osaki M

  8th Symposium of the International Society of Root Research  U.K.
• HMG is a promising key gene for the enhancement of aluminum tolerance of rice via modulating membrane dterols in toot-yip portion  [Not invited]

  Wagatsuma T, Watanabe T, Toyomasu T, Kuroda M, Muranaka T, Ohyama K, Ishikawa A, Usui M, Maejima E, Khan MSH, Tawaraya K, Koyama H

  International Plant Nutrition Colloquium  Turkey
• Characterization of nickel and zinc tolerance, accumulation and mineral profile in the metal hyperaccumulator Noccaea cochleariforme  [Not invited]

  Nishida S, Yoshida J, Watanabe T, Fujiwara T, Miozuno T

  International Plant Nutrition Colloquium  Turkey
• Ionomics study of fertilizer responses in soybean shoots  [Not invited]

  Sha Z, Watanabe T, Ohira K, Okazaki K, Osaki M, Shinano T

  International Plant Nutrition Colloquium  Turkey
• Effects of Organic matter application on the dynamics of organic & inorganic compounds, & microbial activities in Rhizosphere  [Not invited]

  Owadano M, Watanabe T, Osaki M

  International Plant Nutrition Colloquium  Turkey
• Accumulation of non-essential elements in pteridophytes with emphasis on aluminum  [Not invited]

  Watanabe T, Jansen S, Maejima E, Azuma T, Hiradate S, Osaki M

  International Plant Nutrition Colloquium  Turkey
• Phosphorus deficiency enhances the tolerance of rice to the acidic soil stress  [Not invited]

  Maejima E, Watanabe T, Osaki M, Wagatsuma T

  International Plant Nutrition Colloquium  Turkey
• Characteristics of arsenic accumulation in aquatic plants  [Not invited]

  Yamauchi A, Watanabe T, Osaki M

  International Plant Nutrition Colloquium  Turkey
• Physiological responses of Hakea laurina (Proteaceae) to low-P and high-P conditions  [Not invited]

  Maruyama H, Yamauchi T, Kohama T, Watanabe T, Wasaki J

  5th Phosphorus in Soils and Plants Symposium  France
• Varietal difference in the radioactive cesium uptake in Amaranthus and soybean  [Not invited]

  Shinano T, Chu Q, Watanabe T, Matsunami H, Murakami T, Kobayashi D, Okouchi T

  13th International Conference on the Biogeochemistry of Trace Elements  Fukuoka
• Adsorption of radiocesium by metal phytate, major component of soil organic phosphorus  [Not invited]

  Unno Y, Takao A, Eguchi T, Takeda A, Watanabe T, Shinano T

  13th International Conference on the Biogeochemistry of Trace Elements  Fukuoka
• Effect of phosphorus status on distribution of other elements in Hakea laurina (Proteaceae)  [Not invited]

  Maruyama H, Kohama T, Yamauchi T, Watanabe T, Wasaki J

  13th International Conference on the Biogeochemistry of Trace Elements  Fukuoka
• Comparative analysis of aluminium accumulation in leaves of several woody aluminium accumulators  [Not invited]

  Maejima E, Watanabe T, Hiradate S, Jansen S, Osaki M

  The Eleventh Keele Meeting on Aluminium  France
• Differences and similarities in the characteristics of aluminium accumulation in various aluminium accumulators  [Not invited]

  Watanabe T, Maejima E, Hiradate S, Osaki M, Jansen S

  The Eleventh Keele Meeting on Aluminium  France
• The characteristics of root cell components of plants adapted to acidic soil  [Not invited]

  Maejima E, Watanabe T, Wagatsuma T, Osaki M

  Rhizosphere 4  The Netherlands
• Effect of different nitrogen sources on nitrogen dynamics, mineral elements and microbial communities in rhizosphere soil of different plant species  [Not invited]

  Chu Q, Watanabe T, Sha Z, Osaki M

  Rhizosphere 4  The Netherlands
• Ionomic variation in plant species growing in various soil environments  [Not invited]

  Watanabe T, Kusumoto Y, Morita S, Koyanagi T, Osaki M, Hiradate S

  Rhizosphere 4  The Netherlands
• Physiological variations in aluminum accumulation in different aluminum-accumulator plant species  [Not invited]

  Watanabe T, Maejima E, Hiradate S, Wasaki J, Osaki M, Jansen S

  The 9th International Symposium on Plant-Soil Interactions at Low pH  Croatia
• Characteristics of root cell components in aluminum-tolerant woody plants  [Not invited]

  Maejima E, Watanabe T, Wagatsuma T, Osaki M

  The 9th International Symposium on Plant-Soil Interactions at Low pH  Croatia
• Significant role of the plasma membrane (PM) lipid bilayers in aluminum (Al) tolerance of plants  [Not invited]

  Wagatsuma T, Maejima E, Watanabe T, Khan MSH, Ishikawa S, Tawaraya K, Koyama H

  The 9th International Symposium on Plant-Soil Interactions at Low pH  Croatia
• Ionomic variation in leaves of 826 plant species growing in the botanical garden of Hokkaido University, Japan  [Not invited]

  Watanabe T, Maejima E, Osaki M, Azuma T

  Plant Biology Europe EPSO/FESPB 2016 Congress  Czech Republic
• Characteristics of phenolics in root cells of Al-tolerant woody plants  [Not invited]

  Maejima E, Hiradate S, Osaki M, Wagatsuma T, Watanabe T

  Plant Biology Europe EPSO/FESPB 2016 Congress  Czech Republic
• The mechanism of acid tolerance of Lycopodium cernuum L. grown in a solfatara field  [Not invited]

  Saito T, Watanabe T, Nakatsubo T, Wasaki J

  Taiwan Japan Plant Biology 2017  Taiwan

MISC

• マルチオミクスによるダイズ子実収量に関わる複合的要因解析

  村島和基, 丸山隼人, 渡部敏裕, 大津厳生, 草野都, 杉山暁史, 小林奈通子, 濱本昌一郎, 福島敦史, 大熊直生, 藤原風輝, 藤原風輝, 二瓶直登, 市橋泰範, 信濃卓郎  日本土壌肥料学会講演要旨集(Web)  69-  2023
• Effect of nitrogen nutrient conditions on elemental composition and functional constituents in paprika pericarps.

  荒川竜太, 村島和基, 丸山隼人, 渡部敏裕, 信濃卓郎  園芸学研究 別冊  22-  (1)  2023
• シロバナルーピン根域における土壌中リン動態に与える影響の局所的評価

  菅あやね, 丸山隼人, 和崎淳, 渡部敏裕, 信濃卓郎  日本土壌肥料学会講演要旨集(Web)  67-  2021
• ミナトカモジグサの生育および養分状態に応じたリン獲得の分子制御機構

  永山航平, 菅井徹人, 菅井徹人, 佐藤匠, 熊石紀恵, 市橋泰範, 渡部敏裕, 信濃卓郎, 丸山隼人  日本土壌肥料学会講演要旨集(Web)  67-  2021
• トマト尻腐れ発症率の品種間差と果実への無機元素蓄積の関係

  長谷川公紀, 渡邊涼太郎, 丸山隼人, 金山喜則, 信濃卓郎, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  67-  2021
• コムギコアコレクションを用いた可塑的土壌リン獲得形質の品種間差

  青山奈央, 渡部敏裕, 信濃卓郎, 丸山隼人  日本土壌肥料学会講演要旨集(Web)  67-  2021
• 異なる土壌における白花ルーピンの根分泌物分布特性の可視化

  尹永根, 鈴井伸郎, 三好悠太, 海野佑介, 丸山隼人, 和崎淳, 菅あやね, 圓尾明子, 渡部敏裕, 橋本洋平, 内田翔子, 信濃卓郎, 河地有木  日本土壌肥料学会講演要旨集(Web)  67-  2021
• 異なる圃場におけるダイズへの放射性セシウムの移行比較

  鈴木政崇, 藤本久恵, 浅枝諭史, 浅枝諭史, 丸山隼人, 久保堅司, 藤村恵人, 渡部敏裕, 信濃卓郎  日本土壌肥料学会講演要旨集(Web)  67-  2021
• 異なる窒素条件下におけるパプリカ果実の元素組成と尻腐れ果発症との関係

  荒川竜太, 村島和基, 渡部敏裕, 信濃卓郎, 丸山隼人  日本土壌肥料学会講演要旨集(Web)  67-  2021
• 根圏の有機物・ガスに関する植物栄養学研究の一視点-根の細胞壁・細胞膜での各種の化学的・物理的な力と下流遺伝子群への注目

  我妻忠雄, 俵谷圭太郎, 程為国, 渡部敏裕, 丸山隼人, 和崎淳  日本土壌肥料学会講演要旨集(Web)  67-  2021
• 温度処理にともなう元素吸収・分配がパプリカの尻腐れ果発症に与える影響

  鳥山星呂, 荒川竜太, 村島和基, 丸山隼人, 信濃卓郎, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  67-  2021
• シロバナルーピンの放射性セシウム吸収特性と根圏土壌中元素動態の関係

  浅枝諭史, 浅枝諭史, 丸山隼人, 藤本久恵, 久保堅司, 藤村恵人, 渡部敏裕, 信濃卓郎  日本土壌肥料学会講演要旨集(Web)  67-  2021
• 異なる窒素条件下におけるパプリカ果実の機能性成分解析

  村島和基, 荒川竜太, 丸山隼人, 渡部敏裕, 信濃卓郎  日本土壌肥料学会講演要旨集(Web)  67-  2021
• 火山性強酸性土壌に生育する植物の葉身元素組成の特徴

  和崎淳, 和崎淳, 山本晃弘, 山本晃弘, 丸山隼人, 中坪孝之, 中坪孝之, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  67-  2021
• 高オゾン環境下でのヤマナラシ属2種の成長と病虫害の観察-中間報告-

  増井昇, 菅井徹人, 渡邊陽子, 渡部敏裕, 塩尻かおり, 佐々木圭子, 藤戸永司, 荒川圭太, 佐藤冬樹, 小池孝良  北方森林保全技術(Web)  (38)  2021
• A large scale evaluation of effect of changing environment on forest stands: results from a Free Air CO2 or O3 enrichment system

  Koike T, Eguchi N, Watanabe T, Ichikawa K, Fujito E・Qu LY, Watanabe M, Watanabe Y, Agathokleou E, Kitao M, Takagi K, Hiura T, Nakaba S, Satomura T, Funada R, Satoh F  北方森林保全技術  37-  2020/02  [Not refereed][Not invited]
  
• Urban ecology under Ozone pollution: an experimental approach with a Free-Air Controlled Elevated (FACE) O3 system supported by the JST (Japan Science and Technology Agency)

  KOIKE Takayoshi  北方森林保全技術  37-  2020/02  [Not refereed][Not invited]
  
• コムギコアコレクションを用いた根圏リンの形態別評価とリン獲得形質との関係

  青山奈央, 森田洸介, 渡部敏裕, 信濃卓郎, 丸山隼人  日本土壌肥料学会講演要旨集(Web)  66-  2020
• アルミニウム集積植物Melastoma marabathricumにおけるMATE遺伝子の機能解析

  坂口文香, 吉井健祐, 丸山隼人, 佐々木孝行, 西田翔, 和崎淳, 信濃卓郎, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  66-  2020
• ナトリウムによるテンサイの生育促進と光環境の関係

  小濱諒太, 合田健登, 合田健登, 丸山隼人, 菅井徹人, 信濃卓郎, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  66-  2020
• 火山性強酸性土壌に生育するツクシテンツキのイオノミクス解析

  藤原久貴, 丸山隼人, 和崎淳, 信濃卓郎, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  66-  2020
• 白花ルーピンのK欠乏下における根圏土壌中K及びCsの形態変化

  藤本久恵, 高雄惇英, 丸山隼人, 俵谷圭太郎, 信濃卓郎, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  66-  2020
• 土壌窒素バランスに対する小麦の葉位別イオノーム解析と光合成機能の関連

  菅井徹人, 丸山隼人, 渡部敏裕, 信濃卓郎  日本土壌肥料学会講演要旨集(Web)  66-  2020
• ナトリウムによるテンサイの生育促進機構に関する研究

  小濱諒太, 合田健登, 合田健登, 丸山隼人, 菅井徹人, 信濃卓郎, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  66-  2020
• ハーブの養分欠乏ストレスと機能性成分とのかかわり

  伊東和輝, 渡部敏裕, 信濃卓郎, 丸山隼人  日本土壌肥料学会講演要旨集(Web)  66-  2020
• 土壌リン・窒素制限下におけるダイズの生育とリン獲得経路の経時的評価

  浅尾真結子, 渡部敏裕, 信濃卓郎, 丸山隼人  日本土壌肥料学会講演要旨集(Web)  66-  2020
• 土場を想定した踏圧が植栽苗木の成長に及ぼす影響調査(予報) : グイマツ雑種F₁を対象にした試験地の設定

  菅井 徹人, 横山 聡子, 市川 一, 藤戸 永志, 藤田 早紀, 玉井 裕, 渡部 敏裕, 佐藤 冬樹, 小池 孝良  北方森林保全技術  (36)  20  -24  2019/02  [Not refereed][Not invited]
  
• 産地別トドマツ苗木の遮光処理に対する生理成長応答

  菅井徹人, 石塚航, 丸山隼人, 渡部敏裕  日本生態学会大会講演要旨(Web)  66th-  2019
• HMG遺伝子を過剰発現させたイネの金属イオンストレス耐性

  亀岡悠香, 亀岡悠香, 丸山隼人, 我妻忠雄, 黒田昌治, 漆原まりあ, 前島恵理子, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  65-  2019
• 異なる光条件下におけるナトリウムの西洋フダンソウに対する影響

  合田健登, 菅井徹人, 丸山隼人, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  65-  2019
• 窒素欠乏下におけるコムギの光合成特性とモリブデン集積の関係

  菅井徹人, 徳長そよ香, 丸山隼人, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  65-  2019
• コムギにおける低リン耐性および土壌蓄積リン利用能の品種間差

  森田洸介, 渡部敏裕, 丸山隼人  日本土壌肥料学会講演要旨集(Web)  65-  2019
• HMG遺伝子を過剰発現させたイネのアルミニウム耐性獲得について

  亀岡悠香, 丸山隼人, 我妻忠雄, 黒田昌治, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  65-  2019
• 白花ルーピンのカリウム欠乏下における不可給態カリウム及びセシウムの可給化機構

  藤本久恵, 高雄惇英, 丸山隼人, 俵谷圭太郎, 信濃卓郎, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  65-  2019
• 養分欠乏がダイズ種子に与える影響の品種間比較

  浅尾真結子, 丸山隼人, 信濃卓郎, 渡部敏裕  日本土壌肥料学会講演要旨集(Web)  65-  2019
• 日本のコムギコアコレクションにおける土壌中難利用性リン可給化能の品種間比較

  青山奈央, 森田洸介, 渡部敏裕, 信濃卓郎, 丸山隼人  日本土壌肥料学会講演要旨集(Web)  65-  2019
• 異なる窒素栄養および温度条件下で栽培したパプリカ果実の元素動態に関する網羅的解析

  荒川竜太, 藤本久恵, 亀岡悠香, 鳥山星呂, 渡部敏裕, 丸山隼人  園芸学研究 別冊  18-  (2)  2019
• 13 異なる光条件下におけるナトリウムの西洋フダンソウに対する影響（北海道支部講演会）

  合田 健登, 菅井 徹人, 丸山 隼人, 渡部 敏裕  日本土壌肥料学会講演要旨集  65-  (0)  227  -227  2019  [Not refereed][Not invited]
  
• 40 窒素欠乏下におけるコムギの光合成特性とモリブデン集積の関係（北海道支部講演会）

  菅井 徹人, 徳長 そよ香, 丸山 隼人, 渡部 敏裕  日本土壌肥料学会講演要旨集  65-  (0)  236  -236  2019  [Not refereed][Not invited]
  
• 42 HMG遺伝子を過剰発現させたイネのアルミニウム耐性獲得について（北海道支部講演会）

  亀岡 悠香, 丸山 隼人, 我妻 忠雄, 黒田 昌治, 渡部 敏裕  日本土壌肥料学会講演要旨集  65-  (0)  236  -236  2019  [Not refereed][Not invited]
  
• 41 コムギにおける低リン耐性および土壌蓄積リン利用能の品種間差（北海道支部講演会）

  森田 洸介, 渡部 敏裕, 丸山 隼人  日本土壌肥料学会講演要旨集  65-  (0)  236  -236  2019  [Not refereed][Not invited]
  
• P4-1-16 養分欠乏がダイズ種子に与える影響の品種間比較（4-1 植物の多量栄養素，2019年静岡大会）

  浅尾 真結子, 丸山 隼人, 信濃 卓郎, 渡部 敏裕  日本土壌肥料学会講演要旨集  65-  (0)  53  -53  2019  [Not refereed][Not invited]
  
• P4-1-7 日本のコムギコアコレクションにおける土壌中難利用性リン可給化能の品種間比較（4-1 植物の多量栄養素，2019年静岡大会）

  青山 奈央, 森田 洸介, 渡部 敏裕, 信濃 卓郎, 丸山 隼人  日本土壌肥料学会講演要旨集  65-  (0)  50  -50  2019  [Not refereed][Not invited]
  
• P4-1-9 白花ルーピンのカリウム欠乏下における不可給態カリウム及びセシウムの可給化機構（4-1 植物の多量栄養素，2019年静岡大会）

  藤本 久恵, 高雄 惇英, 丸山 隼人, 俵谷 圭太郎, 信濃 卓郎, 渡部 敏裕  日本土壌肥料学会講演要旨集  65-  (0)  50  -50  2019  [Not refereed][Not invited]
  
• P4-3-7 HMG遺伝子を過剰発現させたイネの金属イオンストレス耐性（4-3 植物の有害元素，2019年静岡大会）

  亀岡 悠香, 丸山 隼人, 我妻 忠雄, 黒田 昌治, 漆原 まりあ, 前島 恵理子, 渡部 敏裕  日本土壌肥料学会講演要旨集  65-  (0)  69  -69  2019  [Not refereed][Not invited]
  
• 土壌踏圧と森林の科学 − 欧州と札幌の事例から −

  菅井徹人, 渡部敏裕, 佐藤冬樹, 小池 孝良  森林技術  918:-  30  -33  2018/09  [Refereed][Not invited]
  
• トマト染色体置換系統における果実の細胞壁構成と尻腐れ発症の関係性

  渡邊涼太郎, 富崎亮太, 丸山隼人, 金山喜則, 渡部敏裕  日本土壌肥料学会講演要旨集  64-  50  2018/08/29  [Not refereed][Not invited]
  
• 窒素付加とオゾン暴露がカラマツ属2種苗木の針葉成分に与える影響

  菅井徹人, 渡部敏裕, 北尾光俊, 来田和人, 小池孝良  日本森林学会大会学術講演集  129th-  96  2018/03/26  [Not refereed][Not invited]
  
• トドマツ当年葉のクロロフィル蛍光反応に対するオゾン暴露の影響

  菅井徹人, 北尾光俊, 渡部敏裕, 小池孝良  北方森林研究  (66)  41‐42  2018/02/28  [Not refereed][Not invited]
  
• 塩類化土壌で生育させたグイマツ苗木初期成長に対するオゾン付加の影響

  WANG Yannan, 菅井徹人, 坪奈津美, 渡部敏裕, 小池孝良  北方森林研究  (66)  51‐54  2018/02/28  [Not refereed][Not invited]
  
• 塩類化土壌とオゾン暴露に対するカラマツ属3種苗木の生理応答~クロロフィル蛍光応答に着目して~

  坪奈津美, WANG Yannan, 菅井徹人, 渡部敏裕, 斎藤秀之, 澁谷正人, 小池孝良  北方森林研究  (66)  55‐57  2018/02/28  [Not refereed][Not invited]
  
• トマトの染色体断片置換系統IL8-3を用いた尻腐れ発症機構の解明

  渡邊涼太郎, 富崎亮太, 丸山隼人, 金山喜則, 渡部敏裕  日本植物生理学会年会(Web)  59th-  2018
• P4-3-2 アルミニウム集積植物Melastoma malabathricumのアルミニウムストレスに対する初期応答（ポスター，4-3 植物の有害元素，2018年度神奈川大会）

  吉井 健祐, 丸山 隼人, 西田 翔, 和崎 淳, 渡部 敏裕  日本土壌肥料学会講演要旨集  64-  (0)  69  -69  2018  [Not refereed][Not invited]
  
• P4-2-5 窒素欠乏下で栽培したコムギのモリブデン集積特性（ポスター，4-2 植物の微量栄養素，2018年度神奈川大会）

  徳長 そよ香, 丸山 隼人, 岡田 僚介, 渡部 敏裕  日本土壌肥料学会講演要旨集  64-  (0)  64  -64  2018  [Not refereed][Not invited]
  
• 4-1-5 日本在来種ヤマモガシのクラスター根におけるリン可給化能（4-1 植物の多量栄養素，2018年度神奈川大会）

  岡村 惟史, 渡部 敏裕, 坪田 博美, 和崎 淳  日本土壌肥料学会講演要旨集  64-  (0)  46  -46  2018  [Not refereed][Not invited]
  
• Influence of ground rice chaffs in nursery soil on the quality of paper pots for sugar beet

  大竹 勝, 渡部 敏裕, 大崎 満  日本土壌肥料学雑誌 = Japanese journal of soil science and plant nutrition  88-  (5)  403  -412  2017/10
• How can plant nutrition contribute to solving soil problems in tropical Asia?

  小林 優, 小山 博之, 渡部 敏裕, 前島 恵理子, Sriprachote Anongnat, 落合 久美子, 清水 顕史, 近藤 始彦, 飯泉 佳子, 渡辺 武, 俵谷 圭太郎, 渡邉 彰  日本土壌肥料学雑誌 = Japanese journal of soil science and plant nutrition  88-  (4)  346  -351  2017/08  [Not refereed][Not invited]
   

  熱帯アジア地域における安定的な農業生産は，この地域に生活する人々のみならず，食料を含む各種作物の生産供給をこの地域に大きく依存している我が国にとっても，直接的に重要な課題である。今後も増加が見込まれる世界人口を支えるためには農業生産量のさらなる増加が必要である。しかし，環境への影響を考えれば，従来のような森林伐採による農耕地拡大はもはや困難であり，今後は既存農地の保全と集約的な利用，あるいは荒廃地の修復利用を図っていかなければならない。そこで，本シンポジウムではこれまで実際に熱帯アジア地域をフィールドとして研究に取り組んできた演者から，この地域の農業生産を制限する土壌肥料学的な諸問題を解説してもらうとともに，それら問題を克服する試みの実例についても話題提供を受け，持続可能な農業発展という難しい目標に対して，どのような方向で研究を進めるべきか議論した。以下に講演の概要を紹介する。
• トマトの染色体断片置換系統を用いた尻腐れ果抑制に関する研究

  渡部敏裕, 富崎亮太, 前島恵理子, 丸山隼人, 渡邊涼太郎, 金山喜則, 渡部敏裕  日本土壌肥料学会講演要旨集  63-  2017
• 土壌難利用性リン可給化におけるルーピン根分泌性酸性ホスファターゼLASAP2と有機酸の相乗効果

  古谷浩章, 丸山隼人, 渡部敏裕, 和崎淳  日本土壌肥料学会講演要旨集  63-  2017
• P2-1-14 土壌難利用性リン可給化におけるルーピン根分泌性酸性ホスファターゼLASAP2と有機酸の相乗効果（ポスター，2-1 土壌有機・無機成分の構造・機能・ダイナミクス，2017年度仙台大会）

  古谷 浩章, 丸山 隼人, 渡部 敏裕, 和崎 淳  日土肥講要  63-  (0)  27  -27  2017  [Not refereed][Not invited]
  
• P4-1-1 トマトの染色体断片置換系統を用いた尻腐れ果抑制に関する研究（ポスター，4-1 植物の多量栄養素，2017年度仙台大会）

  渡部 敏裕, 富崎 亮太, 前島 恵理子, 丸山 隼人, 渡邊 涼太郎, 金山 喜則, 渡部 敏裕  日土肥講要  63-  (0)  56  -56  2017  [Not refereed][Not invited]
  
• P4-1-22 クラスタ一根を形成するルーピンとヤマモガシ科植物の低リン環境下での生理応答の比較（ポスター，4-1 植物の多量栄養素，2017年度仙台大会）

  岡村 惟史, 花城 清俊, 丸山 隼人, 俵谷 圭太郎, 渡部 敏裕, 坪田 博美, 和崎 淳  日本土壌肥料学会講演要旨集  63-  (0)  62  -62  2017  [Not refereed][Not invited]
  
• P4-1-18 低リン土壌に生育するヤマモガシが周辺植物のミネラル吸収に及ぼす影響（ポスター，4-1 植物の多量栄養素，2016年度佐賀大会）

  岡村 惟史, 渡部 敏裕, 坪田 博美, 和崎 淳  日本土壌肥料学会講演要旨集  62-  (0)  56  -56  2016  [Not refereed][Not invited]
  
• 4-2-11 Effect of different nitrogen sources on N, mineral elements mobility and microbial metabolism in rhizosphere soil of different plant species

  Chu Qingnan  Abstracts of the meeting, the Society of the Science of Soil and Manure  (61)  68  -68  2015/09/09
• P4-3-8 アルミニウム超耐性をもつ木本植物の根に含まれるフェノリクスの特性(ポスター,4-3 植物の有害元素,2015年度京都大会)

  前島 恵理子, 渡部 敏裕, 我妻 忠雄, 大崎 満  日本土壌肥料学会講演要旨集  (61)  79  -79  2015/09/09
• 4-3-11 ナトリウム処理下におけるテンサイの抗酸化応答(4-3 植物の有害元素,2015年度京都大会)

  土谷 修平, 渡部 敏裕, 松本 卓也, 大崎 満  日本土壌肥料学会講演要旨集  (61)  75  -75  2015/09/09
• P7-2-1 Biocharが有機質肥料を施肥した土壌の窒素動態に与える影響とその要因(ポスター,7-2 土壌改良資材,2015年度京都大会)

  竹内 友規, 渡部 敏裕, 中村 隆一, 本間 千晶, 大崎 満  日本土壌肥料学会講演要旨集  (61)  149  -149  2015/09/09
• 6-4-1 ルーピンとの混植がイネ科牧草の生育および窒素吸収に及ぼす影響(6-4 草地土壌肥沃度,2015年度京都大会)

  藤石 愛美, 渡部 敏裕, 大崎 満  日本土壌肥料学会講演要旨集  (61)  125  -125  2015/09/09
• 7-1-32 テンサイのカリウム施肥、リン酸施肥及び施肥栽培密度の違いが収量・根中糖分及び製糖品質に及ぼす影響について(7-1 肥料および施肥法,2015年度京都大会)

  鷹田 秀一, 渡部 敏裕, 大崎 満  日本土壌肥料学会講演要旨集  (61)  137  -137  2015/09/09
• 17 ナトリウムに対する生育応答の異なるテンサイの選抜(北海道支部講演会,2014年度各支部会)

  松本 卓也, 田口 和憲, 大崎 満, 渡部 敏裕  日本土壌肥料学会講演要旨集  61-  (0)  242  2015  [Not refereed][Not invited]
  
• 8-1-25 土壌に蓄積する有機態リンの主要な形態である難溶性フィチン酸塩の放射性セシウムイオン吸着特性(8-1 環境保全,2015年度京都大会)

  海野 佑介, 高雄 惇英, 江口 哲也, 武田 晃, 渡部 敏裕, 信濃 卓郎  日本土壌肥料学会講演要旨集  61-  (0)  160  -160  2015  [Not refereed][Not invited]
  
• 25 有機物連用土壌および慣行土壌で栽培したミズナとその土壌の成分に与える有機物施肥の影響(北海道支部講演会,2013年度各支部会)

  大熊 直生, 渡部 敏裕, 岡崎 圭毅, 大崎 満  日本土壌肥料学会講演要旨集  (60)  250  -250  2014/09/09
• P4-3-10 イネの塩害に対する生育評価および遺伝学的解析(ポスター,4-3 植物の有害元素,2014年度東京大会)

  清水 克, 石黒 聖也, 渡部 敏裕, 大崎 満, 貴島 祐治  日本土壌肥料学会講演要旨集  (60)  77  -77  2014/09/09
• P4-3-5 異なるアルミニウム集積植物におけるアルミニウムの集積形態と分布(ポスター,4-3 植物の有害元素,2014年度東京大会)

  前島 恵理子, 渡部 敏裕, 平舘 俊太郎, Jansen Steven, 大崎 満  日本土壌肥料学会講演要旨集  (60)  75  -75  2014/09/09
• 4-4-5 有機物連用土壌で栽培されたミズナの成分の特性とその変動要因(4-4 植物の代謝成分と農作物の品質,2014年度東京大会)

  大熊 直生, 渡部 敏裕, 岡崎 圭毅, 岡 紀邦, 大崎 満  日本土壌肥料学会講演要旨集  60-  (60)  81  -81  2014/09/09
• 有機物施用土壌で栽培した作物の根圏環境評価受容性

  大和田野昌子, 渡部敏裕, 海野佑介, 大崎満  日本土壌肥料学会講演要旨集  60-  (60)  248  -248  2014/09/09  [Not refereed][Not invited]
  
• 20 有機物施用土壌で栽培した作物の根圏環境評価受容性(北海道支部講演会,2013年度各支部会)

  大和田野, 昌子, 渡部 敏裕, 海野 佑介, 大崎 満  日土肥講要  60-  (0)  248  -248  2014  [Not refereed][Not invited]
  
• Plant minerals and metabolites analysis for the improvement of plant productivity

  Nakamura Takuji, Hayashi Satoshi, Murakami Noriyuki, Tsuji Noriyuki, Komatsu Kunihiko, Okazaki Keiki, Sha Zimin, Qingnan Chu, Watanabe Toshihiro, Shinano Takuro  Abstracts of Meeting of the CSSJ  237-  (0)  2014  [Not refereed][Not invited]
  
• P4-2-2 塩塚高原に生育する各種植物の土壌環境の違いによるイオノーム変動(ポスター,4-2 植物の微量栄養素,2014年度東京大会)

  渡部 敏裕, 楠本 良延, 森田 沙綾香, 小柳 知代, 大崎 満, 平舘 俊太郎  日本土壌肥料学会講演要旨集  60-  (0)  65  -65  2014  [Not refereed][Not invited]
  
• 4-2-6 Ionome analysis of different organs in soybean at different growth stages in response to different nitrogen sources

  Chu Qingnan, Sha Zhimin  Abstracts of the Annual Meetings, Japanese Society of Soil Science and Plant Nutrition  60-  (0)  62  -62  2014  [Not refereed][Not invited]
  
• 4-4-7 大豆の開花期における展開葉元素含有率とその生産性との関係(4-4 植物の代謝成分と農作物の品質,2014年度東京大会)

  中村 卓司, 山田 哲也, 島田 信二, 村上 則幸, 林 怜史, 辻 博之, 小松 邦彦, 渡部 敏裕, Chu Qingnan, 岡崎 圭毅, 岡 紀邦  日本土壌肥料学会講演要旨集  60-  (0)  82  -82  2014  [Not refereed][Not invited]
  
• P8-1-26 異なる施肥条件での長期連用による土壌の物理化学性の変化に起因した土壌中Cs動態及び植物体へのCs移行量変化の解析(ポスター,8-1 環境保全,2014年度東京大会)

  高雄 惇英, 海野 佑介, 渡部 敏裕, 大崎 満, 信濃 卓郎  日本土壌肥料学会講演要旨集  60-  (0)  161  -161  2014  [Not refereed][Not invited]
  
• 32 Impacts of previous cropping with mycorrhizal plant and manure application on the ionome of soybean seed

  Sha Zhimin, Oka Norikuni, Watanabe Toshihiro, Okazaki Keiki, Osaki Mitsuru, Shinano Takuro  Abstracts of the meeting, the Society of the Science of Soil and Manure  (59)  248  -248  2013/09/11  [Not refereed][Not invited]
  
• Salt tolerance conferred by a plant endogenous peptide elicitor

  Doman K, Watanabe T, Fujino K, Yamaguchi Y  Report of the Hokkaido Branch, the Japanese Society of Breeding and Hokkaido Branch, the Crop Science Society of Japan  54-  (0)  23  -24  2013  [Not refereed][Not invited]
  
• Potential of basic researches in plant nutrition for better agroproduction

  KOYAMA Hiroyuki, KOBAYASHI Yuriko, TAKAHASHI Michiko, SHINANO Takuro, OHKAMA-OHTSU Naoko, MARUYAMA-NAKASHITA Akiko, MIWA Kyoko, KOBAYASHI Masaru, WATANABE Toshihiro, UENO Daisei, NAKAMURA Shin-ichi  Japanese Journal of Soil Science and Plant Nutrition  84-  (2)  136  -141  2013  [Not refereed][Not invited]
  
• P4-3-1 強酸性土壌に生育する植物の根細胞成分の特性(4-3 植物の有害元素)

  前島 恵理子, 渡部 敏裕, 我妻 忠雄, 大崎 満  日本土壌肥料学会講演要旨集  59-  (0)  82  -82  2013  [Not refereed][Not invited]
  
• P4-4-3 野菜のイオノーム解析(4-4 植物の代謝成分と農作物の品質)

  渡部 敏裕, 吉村 誠子, 前島 恵理子, 山内 愛子, 大和田野 昌子, 岡田 遼介, 信濃 卓郎, 大崎 満, 浦山 勝  日本土壌肥料学会講演要旨集  59-  (0)  90  -90  2013  [Not refereed][Not invited]
  
• 35 窒素欠乏下における作物のモリブデン集積特性(北海道支部講演会,2012年度各支部会)

  岡田 遼介, 渡部 敏裕, 浦山 勝, 海野 佑介, 信濃 卓郎, 大崎 満  日本土壌肥料学会講演要旨集  59-  (0)  2013  [Not refereed][Not invited]
  
• 植物種によるセシウム吸収の差違

  渡部敏裕, 東隆行  日本植物生理学会年会要旨集  53rd-  112  2012/03/09  [Not refereed][Not invited]
  
• ミヤコグサAtMOT1相同遺伝子の機能解析

  箱山雅生, DUAN Guilan, 神谷岳洋, FABIEN Lombardo, 横田圭祐, 三輪大樹, 佐藤修正, 田畑哲之, ZHENG Chen, 渡部敏裕, 信濃卓郎, 林誠, 藤原徹  日本植物生理学会年会要旨集  53rd-  374  2012/03/09  [Not refereed][Not invited]
  
• P16-7 有機物施用が作物根圏に与える影響(16.畑地土壌肥よく度,2012年度鳥取大会)

  大和田野, 昌子, 渡部 敏裕, 大崎 満  日本土壌肥料学会講演要旨集  58-  (0)  120  -120  2012  [Not refereed][Not invited]
  
• 11-5 イネの根脂質改変とアルミニウム耐性(11.植物の有害元素,2012年度鳥取大会)

  前島 恵理子, 渡部 敏裕, 松浦 英幸, 黒田 昌治, 豊増 知伸, 岡咲 洋三, 斉藤 和季, 大崎 満, 我妻 忠雄  日本土壌肥料学会講演要旨集  58-  (0)  74  -74  2012  [Not refereed][Not invited]
  
• 12-4 代謝物プロファイリングによる有機物施用の影響評価 : ミズナで観測された有機質肥料に対する特異的な応答(12.植物の代謝成分・農作物の品質,2012年度鳥取大会)

  渡邊 彩乃, 岡崎 圭毅, 渡部 敏裕, 大崎 満, 信濃 卓郎  日本土壌肥料学会講演要旨集  58-  (0)  89  -89  2012  [Not refereed][Not invited]
  
• IV-4 植物イオノミクスの基礎と応用(IV 植物栄養の基礎研究から見えてきた応用への可能性,シンポジウム,2012年度鳥取大会)

  渡部 敏裕  日本土壌肥料学会講演要旨集  58-  (0)  219  -219  2012  [Not refereed][Not invited]
  
• 26 養分欠乏下で栽培した各種作物のイオノーム解析(北海道支部講演会,2011年度各支部会)

  岡田 遼介, 渡部 敏裕, 浦山 勝, 大崎 満  日本土壌肥料学会講演要旨集  58-  (0)  246  -246  2012  [Not refereed][Not invited]
  
• 35 堆肥施用がミズナの代謝プロファイルに与える影響の解析(北海道支部講演会,2011年度各支部会)

  渡邊 彩乃, 岡崎 圭毅, 福田 朋彦, 岡 紀邦, 斎藤 修平, 渡部 敏裕, 大崎 満, 信濃 卓郎  日本土壌肥料学会講演要旨集  58-  (0)  249  -249  2012  [Not refereed][Not invited]
  
• 維管束植物種におけるセシウム集積

  東隆行, 渡部敏裕  日本植物学会大会研究発表記録  75th-  145  2011/09/10  [Not refereed][Not invited]
  
• 35 Ionomic response of Lotus japonicusto different root-zone temperatures

  QUADIR Quazi Forhad, WATANABE Toshihiro, CHEN Zheng, SHINANO Takuro, OSAKI Mitsuru  Abstracts of the meeting, the Society of the Science of Soil and Manure  (57)  297  -297  2011/08/08
• 土壌におけるセシウムの動態とファイトレメディエーション

  渡部敏裕  科学技術政策研究所講演録  (287 (Web))  2011
• Plant Toxic Elements(Division 4: Plant Nutrition,Progress Review)

  Shinano T, Watanabe T  Japanese Journal of Soil Science and Plant Nutrition  82-  (6)  504  -510  2011  [Not refereed][Not invited]
  
• 22-7 植物のセシウムおよびストロンチウム集積特性の解析(22.環境保全)

  渡部 敏裕, 東 隆行, 岡田 遼介, 信濃 卓郎, 浦山 勝, 大崎 満  日本土壌肥料学会講演要旨集  57-  (0)  152  -152  2011  [Not refereed][Not invited]
  
• イネからの根分泌タンパク質のプロテオーム解析

  信濃卓郎, 吉村誠子, KONG Fan‐Jiang, 徳竹俊二, 小松節子, 渡部敏裕, 大崎満, 和崎淳  日本植物生理学会年会要旨集  51st-  349  2010/03/12  [Not refereed][Not invited]
  
• Responses of mineral stress in higher plants

  Makino Amane, YAMAYA Tomoyuki, KAMATA Atsushi, OCHIAI Kumiko, KOYAMA Hiroyuki, MA Jian Feng, WATANABE Toshihiro  Japanese Journal of Soil Science and Plant Nutrition  81-  (2)  181  -189  2010  [Not refereed][Not invited]
   

  第4部門でのシンポジウム企画の目的を述べる前に、当該部門における部会再編の経過を説明する。第4部門では、かねてより、植物栄養学研究の進展と成果を共有したいと言う要望が多く、現在の部会編成が必ずしもその要望に答えるものではない、という意見があった。一方、一つの部会「植物の無機栄養」が極端に肥大化してしまい、一部門の年会発表総数が部門総発表数の60％を超える事態も生じていた。そんな中、2007年の東京大会では、そのような会員の要望に応えて第4部門の一会場開催も試みた。この試み概ね高い評価を受け、継続の要望も多かったが、諸般の事情により2008年の名古屋大会では継続されなかった。また、今年度の京都大会においては、会場の都合上、第4部門一会場開催は不可能となった。
• 11-12 モエジマシダのヒ素耐性における硫黄の重要性(11.植物の有害元素,2010年度北海道大会)

  皇甫 蘭, 渡部 敏裕, 小野寺 とも, 中村 考志, 山口 紀子, 北島 信行, 大崎 満  日本土壌肥料学会講演要旨集  56-  (0)  78  -78  2010  [Not refereed][Not invited]
  
• 11-19 根端細胞膜脂質を改変してアルミニウム耐性植物を創る(2)(11.植物の有害元素,2010年度北海道大会)

  我妻 忠雄, 小山 博之, 渡部 敏裕, 豊増 知伸, 黒田 昌治, 大山 清, 村中 俊哉, 石川 明史, 神成 貴之, 村山 哲也  日本土壌肥料学会講演要旨集  56-  (0)  81  -81  2010  [Not refereed][Not invited]
  
• 16-5 長期継続三要素試験圃場の土壌とそこで栽培したトウモロコシが含む元素の一斉分析(16.畑地土壌肥よく度,2010年度北海道大会)

  渡部 敏裕, 岡田 遼介, 浦山 勝, 大崎 満  日本土壌肥料学会講演要旨集  56-  (0)  114  -114  2010  [Not refereed][Not invited]
  
• 22 ヒ素ストレスに対する植物の代謝応答解析(北海道支部講演会,2009年度各支部会)

  中村 考志, 渡部 敏裕, 岡崎 圭毅, 大崎 満, 信濃 卓郎  日本土壌肥料学会講演要旨集  56-  (0)  245  -245  2010  [Not refereed][Not invited]
  
• P10-5 Characterization of a Lotus japonicus mutant showing strong reduction in Molybdenum accumulation

  Lombardo Fabien, Miwa Hiroki, Sato Shusei, Tabata Satoshi, Chen Zheng, Watanabe Toshihiro, Shinano Takuro, Fujiwara Toru  Abstracts of the meeting, the Society of the Science of Soil and Manure  (55)  88  -88  2009/09/15
• イオノーム解析を用いた栄養吸収変異体の獲得方法

  信濃卓郎, 岡崎圭毅, ZHENG Chen, 渡部敏裕  研究成果情報 北海道農業  2008-  212  -213  2009/06/30  [Not refereed][Not invited]
  
• 9-16 シロバナルーピン由来酸性ホスファターゼ及びフィターゼ過剰発現タバコにおける土壌中有機態リンの利用(9.植物の多量栄養素,2009年度京都大会)

  丸山 隼人, 渡部 敏裕, 信濃 卓郎, 和崎 淳, 大崎 満  日本土壌肥料学会講演要旨集  55-  (0)  70  -70  2009  [Not refereed][Not invited]
  
• P11-14 モエジマシダのヒ素耐性メカニズム : チオール化合物の寄与(ポスター紹介,11.植物の有害元素,2009年度京都大会)

  酒井 有希, 渡部 敏裕, 中村 孝志, 石川 覚, 平舘 俊太郎, 信濃 卓郎, 大崎 満  日本土壌肥料学会講演要旨集  55-  (0)  102  -102  2009  [Not refereed][Not invited]
  
• P20-1 イネ科植物における有機質資材からの窒素獲得(ポスター紹介,20.土壌改良資材,2009年度京都大会)

  横手 美彌, 櫻井 道彦, 榎本 匠, 信濃 卓郎, 関 一人, 岸野 正典, 佐藤 真由美, 大崎 満, 渡部 敏裕  日本土壌肥料学会講演要旨集  55-  (0)  162  -162  2009  [Not refereed][Not invited]
  
• II-7 好酸性植物とアルミニウム(II 植物のミネラルストレス応答,シンポジウム,2009年度京都大会)

  渡部 敏裕  日本土壌肥料学会講演要旨集  55-  (0)  219  -219  2009  [Not refereed][Not invited]
  
• 11 無菌条件下におけるイノシン施与が根の生長に与える影響(北海道支部講演会,2008年度各支部会)

  トクヒサ ダイ, 山村 卓也, 信濃 卓郎, 渡部 敏裕, 横井 大輔, 大崎 満  日本土壌肥料学会講演要旨集  55-  (0)  246  -246  2009  [Not refereed][Not invited]
  
• モエジマシダのヒ素無毒化機構におけるγグルタミルシステイン合成酵素の役割

  酒井有希, 渡部敏裕, 和崎淳, 瀬野浦武志, 信濃卓郎, 大崎満  日本植物生理学会年会要旨集  49th-  109  2008/03/15  [Not refereed][Not invited]
  
• 熱帯泥炭より分離した新規(+)‐catechin資化細菌Burkholderia sp.KTC‐1による(+)‐catechinのtaxifolinへの変換

  松田元規, 大塚祐一郎, 神繁樹, 和崎淳, 和崎淳, 渡辺純, 渡部敏裕, 大崎満  日本農芸化学会大会講演要旨集  2008-  265  2008/03/05  [Not refereed][Not invited]
  
• 01-012 Analysis of diazotroph diversity associated with the rhizosphere of Melastoma malabathricum L.(Soil ecosystem)

  Sato Atsuya, Shinano Takuro, Watanabe Toshihiro, Purnomo Erry, Osaki Mitsuru  日本微生物生態学会講演要旨集  (24)  64  -64  2008  [Not refereed][Not invited]
  
• 9-1 Ionomics study of Lotus japonicus reveals the element homeostasis network in plants

  Quadir Quazi Forhad  Abstracts of the Annual Meetings, Japanese Society of Soil Science and Plant Nutrition  54-  (0)  70  -70  2008  [Not refereed][Not invited]
  
• 9-27 モエジマシダのヒ素無毒化機構におけるチオールペプチドの役割について(9.植物の無機栄養,2008年度愛知大会)

  酒井 有希, 渡部 敏裕, 和崎 淳, 瀬野浦 武志, 信濃 卓郎, 大崎 満  日本土壌肥料学会講演要旨集  54-  (0)  78  -78  2008  [Not refereed][Not invited]
  
• 9-45 シロバナルーピン由来酸性ホスファターゼアイソザイムの発現とプロモーター領域の解析(9.植物の無機栄養,2008年度愛知大会)

  丸山 隼人, 田中 美穂, 和崎 淳, 瀬野浦 武志, 渡部 敏裕, 信濃 卓郎, 伊藤 進, 大崎 満  日本土壌肥料学会講演要旨集  54-  (0)  84  -84  2008  [Not refereed][Not invited]
  
• 11-10 根圏プロテアーゼに着目した、植物の有機態窒素利用の検討(11.植物の栄養生態,2008年度愛知大会)

  榎本 匠, 渡部 敏裕, 岡本 美輪, 櫻井 道彦, 信濃 卓郎, 大崎 満  日本土壌肥料学会講演要旨集  54-  (0)  106  -106  2008  [Not refereed][Not invited]
  
• P20-4 ホウレンソウのヒ素及びカドミウム吸収に対する零価鉄施与の効果(ポスター紹介,20.土壌改良資材,2008年度愛知大会)

  中村 考志, 渡部 敏裕, 酒井 有希, 村田 泰利, 大崎 満  日本土壌肥料学会講演要旨集  54-  (0)  164  -164  2008  [Not refereed][Not invited]
  
• 6 カドミウム耐性を有する微生物による植物生長への影響(北海道支部講演会,2007年度各支部会)

  野村 和弘, 海野 佑介, 渡部 敏裕, 松田 元規, 大崎 満  日本土壌肥料学会講演要旨集  54-  (0)  242  -242  2008  [Not refereed][Not invited]
  
• 8-20 アーバスキュラー菌根共生によるAl感受性植物の耐酸性付与のメカニズム(8.共生,2007年度東京大会)

  稲葉 尚子, 渡部 敏裕, 大崎 満, 江沢 辰広  日本土壌肥料学会講演要旨集  53-  (0)  58  -58  2007  [Not refereed][Not invited]
  
• P9-33 Ion-profile variations of Lotus japonicus wild lines under 9 elements treatment in subtoxic levels

  Zheng Chen  Abstracts of the Annual Meetings, Japanese Society of Soil Science and Plant Nutrition  53-  (0)  87  -87  2007  [Not refereed][Not invited]
  
• P9-43 シダ植物の元素集積特性(9.植物の無機栄養,2007年度東京大会)

  渡部 敏裕, Jansen Steven, 大崎 満  日本土壌肥料学会講演要旨集  53-  (0)  90  -90  2007  [Not refereed][Not invited]
  
• 酸性土壌に生育する植物たち : アルミニウム集積植物に見る多彩な適応のメカニズム

  渡部 敏裕  化学と生物  44-  (7)  496  -499  2006/07/01  [Not refereed][Not invited]
  
• 8-2 Al超集積性植物 Melastoma spp. (ノボタン属植物) の生育およびAl吸収におけるアーバスキュラー菌根共生の役割(8. 共生, 2006年度秋田大会講演要旨)

  稲葉 尚子, 渡部 敏裕, 大崎 満, 江沢 辰広  日本土壌肥料学会講演要旨集  52-  (0)  41  -41  2006  [Not refereed][Not invited]
  
• P9-2 Melastoma malabathricum の根が分泌するムシラゲの性質に関する研究(9. 植物の無機栄養, 2006年度秋田大会講演要旨)

  見澤 誠司, 渡部 敏裕, 大崎 満  日本土壌肥料学会講演要旨集  52-  (0)  74  -74  2006  [Not refereed][Not invited]
  
• P9-6 酸性硫酸塩土壌優占種の生育におけるAlとFeの相互作用(9. 植物の無機栄養, 2006年度秋田大会講演要旨)

  渡部 敏裕, 大崎 満  日本土壌肥料学会講演要旨集  52-  (0)  75  -75  2006  [Not refereed][Not invited]
  
• 11-6 葉菜類におけるアミノ酸吸収とその動態(11. 植物の栄養生態, 2006年度秋田大会講演要旨)

  岡本 美輪, 明石 崇, 大崎 満, 渡部 敏裕  日本土壌肥料学会講演要旨集  52-  (0)  92  -92  2006  [Not refereed][Not invited]
  
• 22-9 零価鉄施与がイネのカドミウム吸収および土壌中カドミウムの形態に与える影響(22. 環境保全, 2006年度秋田大会講演要旨)

  村田 泰利, 渡部 敏裕, 大崎 満  日本土壌肥料学会講演要旨集  52-  (0)  163  -163  2006  [Not refereed][Not invited]
  
• 9-15 Melastoma malabathricumの根が分泌するムシラゲのアルミニウム吸収における役割(9.植物の無機栄養,日本土壌肥料学会 2005年度大会講演要旨集)

  見澤 誠司, 渡部 敏裕, 大崎 満  日本土壌肥料学会講演要旨集  51-  (0)  62  -62  2005  [Not refereed][Not invited]
  
• 9-16 Melastoma malabathricumの根が分泌するムシラゲの特性(9.植物の無機栄養,日本土壌肥料学会 2005年度大会講演要旨集)

  渡部 敏裕, 見澤 誠司, 平舘 俊太郎, 大崎 満  日本土壌肥料学会講演要旨集  51-  (0)  63  -63  2005  [Not refereed][Not invited]
  
• 9-27 重金属汚染土壌を修復するための新たな植物種の選定(9.植物の無機栄養,日本土壌肥料学会 2005年度大会講演要旨集)

  村田 泰利, 渡部 敏裕, 大崎 満  日本土壌肥料学会講演要旨集  51-  (0)  66  -66  2005  [Not refereed][Not invited]
  
• Rhizosphere Management : From Analysis of Rhizosphere Function to Its Control

  NISHIYAMA Masaya, HASHIDOKO Yasuyuki, EZAWA Tatsuya, OHSAKI Mitsuru, ZHANG Fusuo, SAITO Masanori  Japanese journal of soil science and plant nutrition  75-  (3)  405  -410  2004/06/05  [Not refereed][Not invited]
  
• ルーピンの有機態窒素利用特性の解析(11. 植物の栄養生態, 2004年度大会講演要旨集)

  渡部 敏裕, 見澤 誠司, 浦山 勝, 大崎 満  日本土壌肥料学会講演要旨集  50-  (0)  103  -103  2004  [Not refereed][Not invited]
  
• 9-18 低pH条件下で多価カチオンがイネの根伸長に与える影響 : アルミニウムイオンを中心に(9.植物の無機栄養)

  渡部 敏裕, 岡田 謙介  日本土壌肥料学会講演要旨集  49-  (0)  70  -70  2003  [Not refereed][Not invited]
  
• 9-7 イネのアルミニウム耐性品種間差に関する研究(9.植物の無機栄養)

  渡部 敏裕, 岡田 謙介  日本土壌肥料学会講演要旨集  48-  (0)  48  -48  2002  [Not refereed][Not invited]
  
• 11-11 有機態窒素に対するイネ科作物の生育反応特性(11.植物の栄養生態)

  岡本 美輪, 岡田 謙介, 渡部 敏裕, 阿江 教治  日本土壌肥料学会講演要旨集  48-  (0)  78  -78  2002  [Not refereed][Not invited]
  
• 9-32 Melastoma malabathricumのAl集積と生育における有機酸の役割(9.植物の無機栄養)

  渡部 敏裕, 大崎 満  日本土壌肥料学会講演要旨集  47-  (0)  76  -76  2001  [Not refereed][Not invited]
  
• 9-26 Melastoma malabathricum L.のアルミニウム集積に関する研究(9.植物の無機栄養)

  渡部 敏裕, 大崎 満, 但野 利秋  日本土壌肥料学会講演要旨集  46-  (0)  78  -78  2000  [Not refereed][Not invited]
  
• 植物体内でのAlとSiの局在性 (文部省S)

  佐藤純子, 渡部敏裕, 信濃卓郎, 但野利秋  植物・土壌系におけるアルミニウムとケイ酸の相互作用の機構解明 平成8-10年度 No.08406007  59  -69  1999  [Not refereed][Not invited]
  
• 8 リン栄養状態を異にする作物のアルミニウム耐性(北海道支部講演会)

  羅 会明, 渡部 敏裕, 信濃 卓郎, 但野 利秋  日本土壌肥料学会講演要旨集  45-  (0)  322  -322  1999  [Not refereed][Not invited]
  
• 9-26 酸性土壌に適応した木本植物の生育におけるAlと窒素源の相互作用(9.植物の無機栄養)

  渡部 敏裕, 大崎 満, 但野 利秋  日本土壌肥料学会講演要旨集  44-  (0)  77  -77  1998  [Not refereed][Not invited]
  
• Improvement of 8-Quinolinol Method to Determine Low Concentration of Aluminum under the Presence of High Iron and Copper

  WATANABE Toshihiro, MIZUNO Naoharu, TADANO Toshiaki  Japanese Journal of Soil Science and Plant Nutrition  68-  (4)  441  -443  1997  [Not refereed][Not invited]
  
• 9-18 Al集積植物体内におけるAlの分配(9.植物の無機栄養)

  渡部 敏裕, 大崎 満, 吉原 照彦, 但野 利秋  日本土壌肥料学会講演要旨集  43-  (0)  80  -80  1997  [Not refereed][Not invited]
  
• 10-12 低pH土壌適応植物のAlに対する生育反応とAl吸収の特性(10.植物の無機栄養・代謝)

  渡部 敏裕, 大崎 満, 但野 利秋  日本土壌肥料学会講演要旨集  42-  (0)  73  -73  1996  [Not refereed][Not invited]
  
• 10-44 好酸性および耐酸性植物の生育と養分吸収におよぼすAlとCaの施与ならびにpHの影響(10.植物の無機栄養・代謝)

  渡部 敏裕, 大崎 満, 但野 利秋  日本土壌肥料学会講演要旨集  41-  (0)  95  -95  1995  [Not refereed][Not invited]
  
• 5-52 低pH土壌に生育する植物のAl耐性(5.植物の無機栄養および養分吸収)

  大崎 満, 渡部 敏裕, 阿部 孝, 但野 利秋  日本土壌肥料学会講演要旨集  40-  (0)  86  -86  1994  [Not refereed][Not invited]
  
• 6-28 高CO_2がガス交換能と窒素利用効率におよぼす影響のコムギとダイズ間比較(6. 植物の代謝および代謝成分)

  中村 卓司, 大崎 満, 小池 孝良, 但野 利秋  日本土壌肥料学会講演要旨集  39-  (39)  88  -88  1993/03/25  [Not refereed][Not invited]
  

Industrial Property Rights

• 特願2015-115268:セシウム吸着材、その利用、および、フィチン酸鉄塩の製造方法  2015年/06/05

  海野 佑介, 信濃 卓郎, 渡部 敏裕, 高雄 惇英

Research Grants & Projects

• Relationship between vascular plant evolution and aluminum hyperaccumulation

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2023/04 -2027/03 

  Author : 渡部 敏裕, 和崎 淳, 平舘 俊太郎, 佐野 雄三, 丸山 隼人, 東 隆行
• 作物の生理障害の機構解明におけるブレークスルーテクノロジーの開発と検証

  日本学術振興会：科学研究費助成事業

  Date (from‐to) : 2021/04 -2026/03 

  Author : 金山 喜則, 高橋 英樹, 渡部 敏裕, 須川 成利, 栗原 大輔, 黒田 理人
• Utilization of functions by cluster root formation for sustainable crop production

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2021/04 -2025/03 

  Author : 和崎 淳, 坪田 博美, 丸山 隼人, 西田 翔, 渡部 敏裕, 佐々木 孝行, 俵谷 圭太郎, 廣田 隆一

   

  リン酸質肥料は作物生産に必須であるが、資源は涸渇に瀕しており、持続的な作物生産にはその問題の解決が必要である。低リン耐性を有する一部の植物は、クラスター根とよばれる小根が密集した根を形成する能力がある。このクラスター根は、根の表面積を増やし、難利用性リンの吸収を強化して適応するために形成されると考えられているが、その形成能と難利用性リンの供給能の詳細は未解明である。本研究ではシステムズ生物学アプローチ解析によるクラスター根の形態形成イベントの制御、爆発的な根分泌の誘導による難利用性リンからの供給能の解明に取り組む。 これまでに、クラスター根形成種であるシロバナルーピンおよびHakea laurinaのRNA-seqデータなどを元にして複数の有機酸トランスポーター候補の同定に成功した。これらの候補遺伝子の発現量を調査したところ、低リン条件のクラスター根で顕著な発現誘導が確認された。また、シロバナルーピンのRNA-seqデータからクラスター根の発達へのエチレンの寄与が示唆されたことから、エチレン前駆体であるACCおよびエチレン合成阻害剤であるCo2+イオンを添加してその影響を評価した。その結果、エチレンはクラスター根を構成する小根の伸長停止に寄与するとともに、リン欠乏への発現応答にも関与していることが示唆された。 新規なクラスター根形成種の探索を行うため、根のメタバーコーディングライブラリー作成のためのサンプル採集を進めた。クラスター根圏土壌細菌群集のメタバーコーディングを行うため、根圏土壌を採取し、アンプリコンシーケンスの準備を進めた。シロバナルーピンの根箱栽培を実施し、クラスター根におけるリン可溶化に関わる遺伝子発現および土壌中のリン形態を調査した結果、クラスター根の発達段階だけでなく根が形成された位置による違いが認められ、局所的に異なる機能を持つことが明らかとなった。
• Large-scale X-ray fluorescence analysis on plant specimens and construction of information base on element accumulation of plants

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)

  Date (from‐to) : 2020/04 -2024/03 

  Author : 水野 隆文, 渡部 敏裕, 橋本 篤

   

  初年度（2020年）にXRFによる測定方法を確立し，さらに博物館，植物園および大学など植物標本を所有する学術機関と連携し，標本の貸与に関するルールを作成した。そのうえで2021年度は新たに高知県立牧野植物園，東北大学附属植物園，国立科学博物館，岡山大学資源植物科学研究所と連携し，XRFによる元素濃度のデータ収集し，日本の野生植物に関する植物栄養学知見の獲得を進めた。 特に2021年度は日本の国土の30％を占める代表的な土壌型である黒ボク土地帯と，それ以外の地域に分布する野生植物について，イオウとリンの集積レベルに関する解析を実施した。自作標本を含む1,322点の植物標本について解析した結果，次の様な結果を得た。①火山周辺の黒ボク土に分布する野生植物は，非火山灰土壌の植物と比べ統計的に有意にイオウが高く，また健全な生育に必要とされる乾燥重量あたりの濃度(0.1％）を下回った比率は標本全体で17％程度となり，日本の野生植物は火山から供給により十分なイオウ濃度を維持していることが判明した。②黒ボク土では植物のリン吸収が抑制されることが広く知られているが，植物標本の解析結果からは土壌タイプの違いによる集積量の差は認められず，一方でいずれの土壌においても全体の三分の二が健全な生育に必要なリン濃度(0.2%)を下回っていた。よって，リンについては火山灰土壌か否かではなく，土壌に含まれるリン吸着性を有する粘土鉱物（アロフェン）の含有率で比較すべきであることが示唆された。それ以外にも③イオウとリンいずれも木本植物より草本植物での集積量が有意に高い，④植物の科のなかでユリ科の植物に高いイオウ集積性が確認された。⑤植物のイオウとリンの集積量には正の相関が認められる。などのことが新たに確認されるなど，植物のイオウとリンの集積に関する重要な知見を得ることができた。
• Development of two-dimensional ionomics and its application to plant nutrition

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)

  Date (from‐to) : 2020/04 -2023/03 

  Author : 渡部 敏裕, 平舘 俊太郎

   

  昨年度はアルミニウム（Al）および鉄（Fe）処理を施した植物サンプルに含まれる元素をバッファーで抽出し、分子量で分画した後に各元素濃度を測定することを試みた。しかし元素による抽出効率の違いが大きく、分画時に吸着による損失が生じた。そこで、単一のバッファーによる抽出液を分画するのではなく、異なるバッファーで抽出される成分の元素プロファイルに対する処理の影響を調査した。+Al処理と+Fe処理をメラストーマに対して行い、処理後の各部位を中性あるいは酸性バッファーで抽出し、抽出液をICP-MSで測定した。また、サンプルを湿式分解し全濃度についても測定した。その結果、抽出バッファーの違いで傾向が異なる元素が認められた。例えば、若葉でのカルシウムは+Al処理で中性バッファーではコントロールと比べて濃度が著しく低下した一方、酸性バッファーでは大きく上昇した。この傾向は+Fe処理では認められず+Al特有の現象だった。一方、若葉のモリブデン濃度については+Al処理と+Fe処理の両方で酸性バッファーでの濃度が上昇しており、AlとFeの影響は類似した。他の元素においても特徴的な結果は複数認められ、部位間による傾向の違いも見られた。来年度はこれらについても解析を進めたい。それぞれの抽出液における分子量別元素プロファイリングについても検討する。 次に、窒素、リン、カリウムのいずれかを欠乏させた圃場および全て施肥した圃場で栽培した異なる4植物種の根圏および非根圏土壌における抽出性元素濃度の差異を水抽出と0.1 M塩酸抽出でそれぞれ調べた。その結果、水抽出と塩酸抽出では多くの元素で傾向が異なり、根圏において同様の挙動を示す元素グループが複数確認された。種間においても傾向の違いは見られ、それぞれの養分元素に対する植物側の元素集積プロファイルとの比較から植物根の元素可給化能の違いを説明できる可能性が示された。
• How does "Coelacanth" in plant kingdom cope under hyper-stress environments?

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2020/07 -2022/03 

  Author : WASAKI JUN

   

  “Solfatara field” located around volcanic vents is a typical acid sulfate soil, which is the severe environment for plants by the hyper-stresses, such as very low pH, Al toxicity, starvation of essential elements, and inhibition of respiration by hydrogen sulfide. The aim of this study is to investigate the unique tolerant strategies of a Lycophytes, Lycopodium cernuum, which makes pure plant community in solfatara fields. It was indicated that specific tolerances to low-pH and aluminum of L. cernuum were important to grow under the hyper-stressed environments. It is suggested that isolation of free Al ion in vacuole is one of strategies of Al tolerance. Our results also implies that L. cernuum may utilize Al in intact plants. It was suggested that microbial community structure in the rhizosphere of L. cernuum was distinctive in solfatara fields, although involvement of the endophytes in the tolerance of L. cernuum is still unclear.
• Application of trace element solubilizing mechanism in rhizosphere and regulate radioactive cesium uptake

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

  Date (from‐to) : 2019/04 -2022/03 

  Author : SHINANO TAKURO

   

  The short-lived radiocarbon, 11C, is generated as carbon dioxide gas by a cyclotron, collected, and immediately assimilated into the lupin of a legume plant, and a system was constructed to observe the subsequent transfer of 11C to the roots and secretion from the roots to the surrounding soil. The results of the study are shown in Table 1. PET was used for detection. The use of lupin revealed that large amounts of assimilates were secreted from specific root sites (cluster root) into the rhizosphere soil, but not similarly in all cluster roots, and only in certain cluster roots.
• New foresight on root exudation: utilization for agricultural production and ecological function

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

  Date (from‐to) : 2017/04 -2020/03 

  Author : Wasaki Jun

   

  This study aimed (1) to clarify the formation of cluster roots and their function and (2) to survey the possibility to utilize on crop production and their ecological functions using cluster root-forming plants, which have super-tolerant to low-P environments. It was suggested that the sparingly soluble organic P fraction in the rhizosphere soil was mobilized by the cluster roots. It was also suggested that the nutrient accumulation pattern of neighbor plants of cluster root-forming plants was altered by rhizosphere sharing with cluster roots. P accumulation of main crop intercropped with cluster root-forming plants was higher than monocropped plants. This result suggests a possibility to decrease of usage of P fertilizer by intercropping of cluster root-forming plants.
• 樹皮組織のイオノミクス

  文部科学省：科学研究費補助金(挑戦的萌芽研究)

  Date (from‐to) : 2016 -2018 

  Author : 佐野雄三
• 膜脂質層の分子的改変による、イオンストレスマルチ耐性植物の創生

  文部科学省：科学研究費補助金(基盤研究(B))

  Date (from‐to) : 2015 -2017 

  Author : 我妻忠雄
• Why toxic elements can be beneficial in some plant species

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2015 -2017 

  Author : Watanabe Toshihiro

   

  In the present study, as one of the mechanisms responsible for the "beneficial effects" of toxic elements on plant growth, we expected the involvement of the activation of antioxidative stress responses induced by these toxic elements. We focused on aluminum and sodium, which are well known as toxic and beneficial elements. No direct result supporting this hypothesis was observed for aluminum in experiments using Melastoma. For sodium, by contrast, the hypothesis was supported in sugar beet under light-induced oxidative stress. However, chlorophyll fluorescence analysis suggested no involvement of photosynthesis in this phenomenon. Further studies such as measurement of antioxidants seems necessary.
• New development of mechanisms of aluminum accumulation and aluminum tolerance in aluminum accumulator woody plants

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2015 -2017 

  Author : Watanabe Toshihiro

   

  In this study, we comprehensively analyzed how Al-accumulator woody plants adapt to aluminum (Al) stress by analyzing gene expression, element, metabolite, and Al-form mainly using Melastoma malabathricum (Melastoma). As a result, the whole aspect of gene expression related to Al absorption, transportation and accumulation in Melastoma, the importance of Al-citrate chelate in Al accumulation in leaves, and the importance of phenolics in Al accumulation of woody plants were clarified. The results obtained in this study will give many suggestions in future research on mechanisms of adaptation to excess Al / mechanisms of Al accumulation, in Al-accumulator woody plants.
• The study of the mechanism of green stem disorder insensitivity of soybean RILs using metabolomics and ionomics techniques

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2013/04 -2016/03 

  Author : Nakamura Takuji, Okazaki Keiki, Yamada Tetsuya, Shinano Takuro, Fukusaki Eichiro, Watanabe Toshihiro

   

  Green stem disorder (GSD) causes a serious problem in the soybean harvesting because seed coat surfaces are soiled and its quality is deteriorated during machine harvesting. The metabolite- and element-compositions in the stems of soybean RILs with different GSD sensitivity were examined using the metabolomics and ionomics technique to evaluate the relationship between the genetical traits and physiological mechanism of GSD insensitivity. In the sensitive RIL to GSD, the amino acid and organic acid metabolism were activated, results in the increase of nitrogen content of stems. It was suggested GSD was activated the nitrogen metabolism because the increase of the amount of translocation of the element to the stems, not to seeds.
• 開放系オゾン付加施設で生育する冷温帯樹種の成長に及ぼす窒素沈着の影響解明と応用

  文部科学省：科学研究費補助金(基盤研究(B))

  Date (from‐to) : 2014 -2016 

  Author : 小池孝良
• 尻腐れ果の発生機構の解明と克服のための統合的アプローチ

  文部科学省：科学研究費補助金(基盤研究(A))

  Date (from‐to) : 2014 -2015 

  Author : 金山喜則
• イオノミクスを活用した果実の栄養強化に関する研究

  文部科学省：科学研究費補助金(挑戦的萌芽研究)

  Date (from‐to) : 2014 -2015 

  Author : 金山喜則
• Variation of mineral accumulation and acquisition in plant

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2012 -2014 

  Author : Watanabe Toshihiro

   

  In the present study, the diversity of element accumulation was widely investigated in terms of variation by genetic factors, chemical forms and translocation in plant, and soil-plant interaction. Variation in foliar concentration among different species (approximately 850 species) tended to be small in essential elements but large in nonessential elements. Variations in the chemical form of aluminum in leaves of various aluminum accumulators was small, and the common form of Al was detected. In leaves of soybean, concentrations of phosphorus, potassium, and cupper decreased and those of many other elements, particularly molybdenum, increased with aging. The correlations of element concentrations between leaf and soil (available concentration) were determined in each element and in each species. Only some elements showed positive correlations under phylogenetic influence.
• Making of multi-tolerant plants against complexed acid-soil stresses by molecular modifications of membrane lipid layers

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))

  Date (from‐to) : 2011 -2013 

  Author : Tadao WAGATSUMA, Keitarou TAWARAYA, Jun WASAKI, Toshihiro WATANABE, Hiroyuki KOYAMA, Tomonobu TOYOMASU, Masaharu KURODA, Akira OIKAWA

   

  In order to lower the content of phospholipids and to increase that of sterols in roots, we made the new plants by modification using two different techniques, i.e., culturing method and molecular method: Al-sensitive rice cultivar Koshihikari grown previously under P-deficient conditions and transformed by the overexpressions of PAH (key gene to exchange phospholipids into galactolipids) and HMG (key gene to biosynthesize sterols). Al tolerance and low-Ca tolerance under low pH conditions of P-deficient Al-sensitive Koshihikari were significantly enhanced, and Al tolerance and low-P tolerance of the several lines of the transformed Koshihikari were also enhanced. Among several tens of rice cultivars, low-P tolerant rice cultivar was found out to have a specific characteristics on the decomposition of P-containing metabolites. Several genes contributing to P-recycling ability were identified together with each function.
• Ionomic response of plant to environmental stress

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(若手研究(B))

  Date (from‐to) : 2010 -2011 

  Author : Toshihiro WATANABE

   

  Effects of nutrient deficiency and aluminum toxicity stresses on plant ionome, all the mineral nutrient and trace elements found in an organism, were investigated. Nitrogen, phosphorus, and potassium deficiencies greatly changed ionome profile in plant. Among analyzed elements, changes in concentration of molybdenum and cesium were noticeable. It was expected that increase in molybdenum concentration under nitrogen deficient conditions could be related to nitrogen-fixing microorganisms. Aluminum stress also affected ionome profile in plant
• Cesium accumulation in plant

  Date (from‐to) : 2010
• イオノームによるミヤコグサの養分動態変異体の獲得と解析

  文部科学省：科学研究費補助金(特定領域研究)

  Date (from‐to) : 2008 -2009 

  Author : 信濃 卓郎, 渡部 敏裕

   

  マメ科モデル植物のミヤコグサ(Lotus japonicus)の養分吸収変異体を獲得するために、これまでに確立した吸収元素の網羅的解析手法であるイオノーム手法を用いた。変異体のスクリーニング対象としてはEMS(ethylmethane sulfonate)処理を行った種子を自分たちで調整した約200系統およびミヤコグサバイオリソースセンターから提供された約7000糸統を用いた。スクリーニング対象とした元素は必須元素としてはB, Mg, K, Ca, Mn, Fe, Cu, Zn, Mo、非必須元素としてはAI, As, Na, Ni, Sr, Cd, Csであり、非必須元素は野生株の生育に障害が出ない程度のレベルで培養液に添加して栽培を行なった。栽培は一定の環境条件下で同時に200系統を栽培し、全ての個体の地上部を別々に分解をし、対象元素含有率の測定をICP-MSを用いて行った。 200系統全体を母集団として、その平均から3倍以上あるいは半分以下にいずれかの元素含有率が変動した場合に変異を生じている候補として選抜し、地上部を切除した後の根部から植物体を再生することで種子を獲得した。同様の操作を繰り返し4世代目にいたっても元素含有率に変動か生じることを確認した系統を変異系統とした。 2000系統から32の変異系統が獲得された。得られた変異体の中で一つの元素だけが変動している系統は少なく、その平均は4-5種類の元素が同時に変異していることが示された。また元素の種類によっては変動株が多く得られるものがあり、その逆も認められた。実際に獲得したMoの変異株は体内めMoトランスポーターに変異が生じていることが確認され、本手法の有効性が認められた。また、化学的性質の異なる元素が体内においで一定のバランスを持っで存在するイオンホメオスタシスの現象が認められ、変異によってこのバランスかくずれる可能性が初めて示唆された。
• 体内イオンバランスの調整に関与する遺伝子のイオノームによる解析手法の開発

  文部科学省：科学研究費補助金(特定領域研究)

  Date (from‐to) : 2006 -2007 

  Author : 信濃 卓郎, 渡部 敏裕

   

  誘導結合プラズマ質量分析(ICP-MS)法を用いてマメ科のモデル植物であるミヤコグサの各種有害元素(アルミニウム、ヒ素、カドミウム、セシウム、鉛、モリブデン、ニッケル、塩、ストロンチウム)の吸収、利用機構についての網羅的解析を進めた。昨年度までに各種有害元素の施与条件、分析条件等の確立を行ない、これまでに変異剤(EMS)処理を行なった約2000株の養分吸収能に関わる変異のスクリーニングを進めた。有害元素を含む20種類の異なる元素に関して植物体全体での濃度に変異が認められる系統、特定の部位(根あるいは地上部)に局在する系統を中心に植物と種子の獲得を行なっている。その結果、銅,マンガン,マグネシウム,モリブデン,カドミウム,ニッケル,ヒ素に関して通常の野生株とは全くことなる挙動を示す変異株が存在することが明らかとなった。このように、当初の目的であるイオノームによる解析手法の開発はほぼ完了したと判断される。そこで、特に挙動の異なるマグネシウム変異体に関して戻し交雑をすすめることにより、変異を引き起こしている遺伝子の獲得を進めている。このマグネシウム変異体は地上部へのマグネシウムの移行が抑制されており、生育量に大きな違いは出ないにも関わらず葉脈間に黄化が認められるという表現系を伴うため、変異の発現の確認が用意である利点もある。ミヤコグサはマメ科のモデル植物であり、マメ科はイネ科植物と比較してカルシウム、マグネシウムの吸収量が多いことが知られており、同じ二価のカチオンであるマグネシウムの吸収移行変異体の獲得は今後のマメ科作物の養分吸収機構を解析するための極めて重要な情報を提供することが期待される。
• 重金属集積植物の探査とその機能解析

  文部科学省：科学研究費補助金(若手研究(B))

  Date (from‐to) : 2004 -2006 

  Author : 渡部 敏裕

   

  1)昨年度までの実験で、インディアンマスタードとアマランサスは水耕条件では地上部に同程度カドミウムを集積するが、土耕条件ではインディアンマスタードの集積能力はアマランサスと比べて著しく劣ることがわかった。本年度の研究から、この土耕における異なる集積能力は根から分泌される主要な有機酸の種類が関与していることが示唆された。すなわち、アマランサスは不溶性カドミウムを可溶化する能力の高いクエン酸を分泌する一方、インディアンマスタードは可溶化能の低いシュウ酸が分泌性有機酸の主体であった。インディアンマスタード、アマランサスともにカドミウム以外の重金属も超集積する傾向があり、様々な重金属に汚染された土壌のファイトレメディエーションに利用可能であることが示唆された。2)昨年度までの実験で、カドミウム汚染土壌への零価鉄添加が植物のカドミウム集積低減に有効である事がわかった。本年度はその低減メカニズムを土壌化学的手法により解明した。カドミウムで汚染した水田土壌に零価鉄を添加することにより、土壌中のカドミウムは、植物に吸収されやすい交換態などの形態が減少し、吸収されにくい吸蔵態画分が増加することが明かとなった。3)鉱山跡地に生育する野生植物の根圏より採取した土壌から、カドミウム耐性細菌を分離した。分離した細菌をイネ幼植物体の根に塗布し、カドミウム汚染土壌で無菌栽培したところ、塗布しなかったコントロールと比較して大きく生育が改善された。
• Investigation and application of adaptation strategies of plant roots to acid soil.

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(A))

  Date (from‐to) : 2004 -2006 

  Author : Mitsuru OSAKI, Takuro SHINANO, Toshihiro WATANABE, Hiroyuki KOYAMA, Keitaro TAWARAYA, Jun WASAKI

   

  This study aimed to solve problems on acid soils for utilization as arable soils. Critical problems of acid soil are 1) toxicity of metallic ions and 2) phosphorus starvation. Some plant species have been developed some strategies to adapt on acid soils. We have shown that the several root exudates bring the tolerance to stresses on acid soils. Therefore, the secreting abilities of plant roots were investigated in this study.A gene for secretory acid phosphatase isolated from white lupin, which is well known as a phosphorus tolerative plant, was introduced into tobacco plants. The growth and phosphorus acquisition of transgenic plant were improved from wild type plants. To investigate the secreting ability of organic acid, which can liberate inorganic phosphate from sparingly soluble forms, malate exudation of Arabidopsis was chosen as a model. It was indicated that malate release was induced by the up-regulation of malate transporter protein. The induction of malate transporter expression by aluminum was specific in the root tips and internal tissues of roots, suggesting that the mechanism is regulated to minimize the carbon consumption. It is concluded that site-specific regulation of the transporters is required to improve the inorganic phosphate uptake ability.It was suggested that the specificities of mucilage, consisted of polysaccharides, in the root exudates differed among plant species. The highest affinities of mucilage of Melastoma malabathricum and maize were shown with trivalent and divalent cations, respectively. The affinity of mucilage of Melastoma malabathricum was high to aluminum ion, though the binding strength was quite lower than that of maize. It was supposed that not only the composition of sugar but also methylation of uronic acids were involved in the differences of adsorption specificity to the cation. Separation and purification of substances involved in the elongation of mycorrhizal hyphae was conducted. It was succeeded that an A2 fraction, which induced an elongation and secondary and further branching of mycorrhizal hyphae was obtained from root exudates of onion.
• Ionomics in plant and soil

  Date (from‐to) : 2003
• Acid soil tolerance in plants

  Date (from‐to) : 1992

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