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Last Updated :2024/07/25

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Master

Affiliation (Master)

  • Research Faculty of Agriculture　Fundamental AgriScience Research　Agrobiology and Bioresources

Affiliation (Master)

  • Research Faculty of Agriculture　Fundamental AgriScience Research　Agrobiology and Bioresources

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Profile and Settings

Profile and Settings

  • Name (Japanese)

    Jitsuyama

  • Name (Kana)

    Yutaka

  • Name

    200901067764535265

Alternate Names

Achievement

Research Interests

  • Hydroponic culture   Natural farming   Root System   Cell Ultrastructure   Horticultural Crop   Freezing tolerance   Waterlogging tolerance   Germination   Environmental Stress   Field Crops   

Research Areas

  • Environmental science/Agricultural science / Horticulture / Horticultural Science
  • Environmental science/Agricultural science / Crop production science / Crop Science

Research Experience

  • 2011/09 - Today Hokkaido University Research Faculty of Agriculture Lecturer
  • 2000/02 - 2011/08 Hokkaido University Research Faculty of Agriculture Assistant instructor

Education

  • 1996/04 - 1999/09  Hokkaido University  Department of Agriculture  Doctor course

Awards

  • 1999 Student Poster Second Prize in The 36th Annual Meeting of the Society for Cryobiology (Marseille-France)

Published Papers

  • Sunao Shoji, Hideyuki Saito, Yutaka Jitsuyama, Kotono Tomita, Qiang Haoyang, Yukiho Sakurai, Yuhei Okazaki, Kota Aikawa, Yuki Konishi, Kensei Sasaki, Koji Fushimi, Yuichi Kitagawa, Takashi Suzuki, Yasuchika Hasegawa
    SCIENTIFIC REPORTS 12 (1) 2045-2322 2022/10 
    The stimulation of photosynthesis is a strategy for achieving sustainable plant production. Red light is useful for plant growth because it is absorbed by chlorophyll pigments, which initiate natural photosynthetic processes. Ultraviolet (UV)-to-red wavelength-converting materials are promising candidates for eco-friendly plant cultures that do not require electric power. In this study, transparent films equipped with a UV-to-red wavelength-converting luminophore, the Eu3+ complex, were prepared on commercially available plastic films for plant growth experiments. The present Eu3+-based films absorb UV light and exhibit strong red luminescence under sunlight. Eu3+-painted films provide significant growth acceleration with size increment and biomass production for vegetal crops and trees in a northern region. The plants cultured with Eu3+-painted films had a 1.2-fold height and 1.4-fold total body biomass than those cultures without the Eu3+ luminophores. The present film can promote the plant production in fields of agriculture and forestry.
  • Satoshi Oku, Keiji Ueno, Yukiko Sawazaki, Tomoo Maeda, Yutaka Jitsuyama, Takashi Suzuki, Shuichi Onodera, Kaien Fujino, Hanako Shimura
    Journal of Experimental Botany 73 (14) 4908 - 4922 0022-0957 2022/08/11 
    Abstract Fructans such as inulin and levan accumulate in certain taxonomic groups of plants and are a reserve carbohydrate alternative to starch. Onion (Allium cepa L.) is a typical plant species that accumulates fructans, and it synthesizes inulin-type and inulin neoseries-type fructans in the bulb. Although genes for fructan biosynthesis in onion have been identified so far, no genes for fructan degradation had been found. In this study, phylogenetic analysis predicted that we isolated a putative vacuolar invertase gene (AcpVI1), but our functional analyses demonstrated that it encoded a fructan 1-exohydrolase (1-FEH) instead. Assessments of recombinant proteins and purified native protein showed that the protein had 1-FEH activity, hydrolyzing the β-(2,1)-fructosyl linkage in inulin-type fructans. Interestingly, AcpVI1 had an amino acid sequence close to those of vacuolar invertases and fructosyltransferases, unlike all other FEHs previously found in plants. We showed that AcpVI1 was localized in the vacuole, as are onion fructosyltransferases Ac1-SST and Ac6G-FFT. These results indicate that fructan-synthesizing and -degrading enzymes are both localized in the vacuole. In contrast to previously reported FEHs, our data suggest that onion 1-FEH evolved from a vacuolar invertase and not from a cell wall invertase. This demonstrates that classic phylogenetic analysis on its own is insufficient to discriminate between invertases and FEHs, highlighting the importance of functional markers in the nearby active site residues.
  • R. Ide, A. Ichiki, T. Suzuki, Y. Jitsuyama
    Scientia Horticulturae 295 0304-4238 2022/03/15 
    Waterlogging conditions cause severe abiotic stress and reduce average yields in vegetable crops. Processing tomatoes are cultivated extensively worldwide, and are used in many food products. Recently, processing tomatoes have been cultivated in paddy fields in Hokkaido, northern Japan. Studies are needed to assess the responses of processing tomatoes to wet conditions. The goal of this study was to clarify the mechanisms of waterlogging injury, and to identify ways to mitigate wet injury in processing tomatoes. We used three cultivars in a two year pot experiment and a one year field experiment. Longer waterlogging treatments increased the severity of yield losses in both experiments. The waterlogging treatments initially caused reductions in fruit number and then in average fruit weight. The reductions in fruit number resulted from reduced fruiting ratios. The reductions in average fruit weight may have been triggered by multiple factors, including reductions in soil nutrients, reduced nutrient uptake due to hypoxia, and reductions in the photosynthetic rate. These results suggested that top-dressing with fertilizer after excess rain may help to mitigate yield losses. The waterlogging treatments also induced changes in fruit composition, with reduced water content and increased sugar/acid ratios. The responses to waterlogging treatment varied among cultivars, and we concluded that ‘Natsunoshun’ is a superior cultivar for cultivation in converted paddy fields that may become waterlogged after heavy rains.
  • Y. Jitsuyama, Y. Kita, K. Arakawa, T. Suzuki
    VITIS 61 (4) 125 - 132 0042-7500 2022 
    Hokkaido in northern Japan is a typical subpolar region and wine production using traditional cultivars can be done recently. However, there is an issue that the grapevines have short life spans in snowy central Hokkaido. This study investigates the effect of snow it-self and its interaction with vineyard slope and grape-vine stiffness on physical stress. In comparison of the flatness of the vineyard, the distortion of the basal trunk in the slope zone was greater than in the flat zones in the snowy mid-season. In comparison between cultivars, the distortion of the basal trunk in the flexible 'Kerner' was greater than in rigid 'Gewurztraminer', even in the flat zones. The magnitude of the distortion coincides with the mortality of grapevines. Although the chang-es in distortion showed a transition in just two winter durations, these results suggested a possibility that the snow cover might be linked to one of the physical dam-ages of grapevines in vineyards in heavy snowy regions.
  • Arisa Osada, Kentaro Horikawa, Youichi Wakita, Hideo Nakamura, Mitsuko Ukai, Hanako Shimura, Yutaka Jitsuyama, Takashi Suzuki
    SCIENTIA HORTICULTURAE 291 0304-4238 2022/01 
    Fruits of the genus Rosa plants are called rose hips. The common hips of R. canina are well known as a rich source of antioxidants like ascorbic acid and polyphenols. To investigate availability in the hips in Rosa spp., wild Rosa hips originating from East Asia, i.e. R. acicularis, R. davurica, R. multiflora and R. rugosa were evaluated in terms of the content of antioxidants and antioxidant ability in the hydrophilic extracts. The hips from R. glauca originating from south Europe and its interspecific hybrids ('Kitaayaka' and 'Consared'), and purchased R. canina hips were also examined. In addition to the colorimetric detections of DPPH and ORAC, ESR-ST methods were employed for evaluating antioxidant ability, which can determine scavenging activities against naturally-occurring ROS i.e. superoxide anion radical (center dot O2-), hydroxyl radical (HO center dot), alkoxyl radical (RO center dot) and singlet oxygen (1O2), individually. The hips of R. davurica and 'Consared' showed quite high values in both the total content of ASA plus DHA (40.8-103.1 g/kg DW) and total polyphenols (119.2-161.5 g quercetin eq./kg DW) regardless of the years collected. They also had high antioxidant activities against each radical compared to other rose hips, and thus their antioxidant ability seems multiple. Both ASA and polyphenols could scavenge radicals of ROO center dot and 1O2, since significant correlations (P< 0.05) were confirmed. However, polyphenols might have greater contribution to the antioxidant activities, because the correlation coefficients were higher in total polyphenols than ASA. R. davurica can be one of the useful genetic resources for breeding cultivars which will bear antioxidant-rich rose hips, since 'Consared' is a progeny of R. davurica x glauca.
  • Keita Sugiyama, Hanako Shimura, Daisuke Kami, Naho Murata, Midori Yoshida, Akihiro Suzuka, Kohei Nagaoka, Yutaka Jitsuyama, Takashi Suzuki
    Scientia Horticulturae 289 110210 - 110210 0304-4238 2021/11
  • Reiko Horiuchi, Keita Arakawa, Jun Kasuga, Takashi Suzuki, Yutaka Jitsuyama
    CRYOBIOLOGY 101 44 - 51 0011-2240 2021/08 
    In high-latitude regions, the cold hardiness of buds and canes of grapevine is important for budburst time and yield in the next season. The freezing resistance of buds and canes sampled from six wine grapes currently cultivated in Hokkaido, Japan, all of them grown from autumn to winter, was investigated. A significant difference between the cultivars in their freezing resistance was detected in the buds harvested in winter. In addition, outstanding differences in the lower temperature exotherms (LTE) related to the supercooling ability of tissue cells happened in the winter buds, and there is a close relationship between freezing resistance and LTE detected in the winter buds. This suggests that the supercooling ability of tissue cells in winter buds is strongly related to the freezing resistance. However, detailed electron microscopy exposed that the differences in freezing resistance among cultivars appeared in freezing behavior of leaf primordium rather than apical meristem. This indicated that as the water mobility from the bud apical meristem to the spaces around the cane phloem progressed, the slightly dehydrated cells improved the supercooling ability and increased the freezing resistance.
  • Jitsuyama Y, Ichiki A, Ide R, Shimura H, Suzuki T
    The Horticulture Journal 88 (2) 232 - 244 2189-0102 2019/04 [Refereed][Not invited]
     
    An excess or lack of soil moisture are significant abiotic stresses that reduce the average yield for vegetable crops worldwide. The responses of 'Natsunoshun', a processing tomato cultivar, to water stress at three growth stages, first flower differentiation, first flowering, and fruit development, were investigated over a two-year period. The year effect on yield was not significant; however, the growth stage and the type of water stress at a particular growth stage affected yield significantly. Either an excess or lack of soil moisture after the first flowering stage were significant in reducing yield. The decrease was related to the average weight of the fruit rather than the number per plant. Under dry conditions, fruit number was the same as control plants, but there was a decrease in the reddish mature fruit ratio. On the other hand, under wet conditions plant biomass decreased, especially in the roots, even if there was a transition from wet to dry conditions. We conclude that excessive soil moisture during the first flowering stage produces slower CGR and decreased biomass in the roots, which we believe is the reason for the yield decline.
  • Horikawa K, Hirama T, Shimura H, Jitsuyama Y, Suzuki T
    Plant Science 278 107 - 112 0168-9452 2019/01 [Refereed][Not invited]
  • Oku Satoshi, Ueno Keiji, Tsuruta Yu, Jitsuyama Yutaka, Suzuki Takashi, Onodera Shuichi, Maeda Tomoo, Shimura Hanako
    Scientia Horticulturae 247 147‐155 - 155 0304-4238 2019 [Refereed][Not invited]
  • Rice (Oryza sativa L.) germplasm with better seedling emergence under direct sowing in flooded paddy field
    Kashiwagi J, K. Hamada, Y., Jitsuyama
    Plant Genetic Resources 16 (4) 352 - 358 2018 [Refereed][Not invited]
  • Hypoxia-responsive root hydraulic conductivity influences soybean cultivar-specific waterlogging tolerance
    JITSUYAMA Yutaka
    American Journal of Plant Science 8 770 - 790 2017 [Refereed][Not invited]
  • ダイズ湿害発生メカニズムに関するいくつかの考察 -効率的な耐湿性育種サーベイ法考案に向けての 一助として-
    実山 豊
    グリーンテクノ情報 11 (2) 8 - 11 2015/10 [Not refereed][Invited]
  • Yutaka Jitsuyama
    CANADIAN JOURNAL OF PLANT SCIENCE 95 (5) 999 - 1005 0008-4220 2015/09 [Refereed][Not invited]
     
    Excess soil moisture induces hypoxia, causing waterlogging injury in soybeans [Glycine max (L.) Merr.]. Twelve Japanese soybean cultivars with varying hypoxia tolerance were used. Of these, 11 (all but Hayahikari) were evaluated for waterlogging tolerance using a scaled index with data from previous studies. To investigate hypoxic responses, cultivars were grown under hydroponic conditions for 2 wk a year for 2 yr, with aerobic or hypoxic oxygen concentrations artificially maintained in the rhizosphere. Hypoxic responses (measured as plant dry weight and root morphology) were assessed at the early vegetative stage. The effects of hypoxic treatment on root dry weight were significant, and the effect of year on soybean dry weight was not significant. The change in root dry weight, and particularly, in coarse root length, was significantly correlated with waterlogging tolerance index at the 0.001 probability level. This study showed that root responses to rhizosphere hypoxia might reflect waterlogging tolerance in soybeans.
  • Hiroshi Uchino, Kazuto Iwama, Yutaka Jitsuyama, Toshiko Yudate, Satoshi Nakamura, Jai Gopal
    PLANT PRODUCTION SCIENCE 18 (2) 187 - 196 1343-943X 2015/04 [Refereed][Not invited]
     
    Weeds are the most serious threat to crop production in organic farming systems. Information on the spatial distribution of weeds is important for effective weed management. The objective of this study was to evaluate the effect of the ground cover of the main crops (soybean and maize) and cover crop on the spatial distribution of weeds for two row sections, 'within the row (IR)' and 'between the rows (BR)'. The cover crop was interseeded in BR 3 - 4 weeks after sowing the main crops in two years, and weed density and vegetation cover ratio (VCR, an index of ground cover) of the main crops and cover crop were measured. There was a significant difference in the spatial distribution of weeds between the two main crops. In IR, weed density was higher in maize than in soybean, while in BR, it was higher in soybean. This means that weed suppression in IR was more important for maize, while the suppression in BR was more important for soybean. The negative relationship between VCR of the main crop plus cover crop and weed density in each row section suggests that the difference in ground cover was one of the reasons for the difference in weed density between the two main crops. The cover crop markedly increased the VCR in BR, but only slightly increased VCR in IR in both main crops. These results suggest that the cover crop was more compatible with soybean than with maize, because the high weed density in IR of maize could not be decreased sufficiently by the slight increase of VCR in BR by the cover crop.
  • Kashiwagi J, Y. Morito, Y. Jitsuyama, P. An, T. Inoue, M. Inagaki
    J. Agronomy and Crop Science 201 161 - 172 2015 [Refereed][Not invited]
  • Jang SJ, Sato M, Sato K, Jitsuyama Y, Fujino K, Mori H, Takahashi R, Benitez ER, Liu B, Yamada T, Abe J
    PloS one 10 (6) e0128527  1932-6203 2015 [Refereed][Not invited]
     
    Physical dormancy, a structural feature of the seed coat known as hard seededness, is an important characteristic for adaptation of plants against unstable and unpredictable environments. To dissect the molecular basis of qHS1, a quantitative trait locus for hard seededness in soybean (Glycine max (L) Merr.), we developed a near-isogenic line (NIL) of a permeable (soft-seeded) cultivar, Tachinagaha, containing a hard-seed allele from wild soybean (G. soja) introduced by successive backcrossings. The hard-seed allele made the seed coat of Tachinagaha more rigid by increasing the amount of beta-1,4-glucans in the outer layer of palisade cells of the seed coat on the dorsal side of seeds, known to be a point of entrance of water. Fine-mapping and subsequent expression and sequencing analyses revealed that qHS1 encodes an endo-1,4-beta-glucanase. A single-nucleotide polymorphism (SNP) introduced an amino acid substitution in a substrate-binding cleft of the enzyme, possibly reducing or eliminating its affinity for substrates in permeable cultivars. Introduction of the genomic region of qHS1 from the impermeable (hard-seeded) NIL into the permeable cultivar Kariyutaka resulted in accumulation of beta-1,4-glucan in the outer layer of palisade cells and production of hard seeds. The SNP allele found in the NIL was further associated with the occurrence of hard seeds in soybean cultivars of various origins. The findings of this and previous studies may indicate that qHS1 is involved in the accumulation of beta-1,4-glucan derivatives such as xyloglucan and/or beta-(1,3)(1,4)-glucan that reinforce the impermeability of seed coats in soybean.
  • Yutaka Jitsuyama, Yuma Hagihara, Yutaro Konno
    SEED SCIENCE RESEARCH 24 (1) 37 - 48 0960-2585 2014/03 [Refereed][Not invited]
     
    Soybean seeds are prone to flooding injury just after planting if they are exposed to excess moisture. We investigated the flooding tolerance of soybean seeds to clarify the relationship between flooding injury and imbibition, to identify factors that could provide fundamental information for the breeding of flooding-tolerant cultivars. Seven cultivars were used for this study. The seeds were geminated in a paper towel after a flooding treatment and then evaluated for survival. The imbibition of submerged seeds (passive imbibition) was evaluated as the seed fresh weight change during the flooding process. The imbibition of seeds with capillary effect (capillary imbibition) was measured by the bottom water supply method. Furthermore, the conductivity of the seed coat and seed osmolarity were measured. After 3h of flooding, significant differences in survival were detected among cultivars. In addition, the passive imbibition during 10-30min of flooding, and the capillary imbibition during 0-10min of flooding were caused by significant differences in the imbibition rate among cultivars. Although neither imbibition showed a significant correlation with the survival directly, the ratio between the passive and the capillary imbibition rate was significantly correlated with survival. Factors affecting imbibition included the hydraulic conductivity of the seed coat and seed osmolarity, which were significantly correlated with the passive and the capillary imbibition rate, respectively. Thus, the balance between the capillary and passive imbibition behaviour of seeds, affected by the hydraulic conductivity of the seed coat and seed osmolarity, was closely correlated with the occurrence of flooding injury in soybean seeds.
  • Responses of Japanese soybeans to hypoxic condition at rhizosphere were different depending upon cultivars and ambient temperatures
    JITSUYAMA Yutaka
    American Journal of Plant Science 4 1297 - 1308 2013 [Refereed][Not invited]
  • Shigeto Fujimura, Peili Shi, Kazuto Iwama, Xianzhou Zhang, Jai Gopal, Yutaka Jitsuyama
    PLANT PRODUCTION SCIENCE 15 (2) 118 - 124 1343-943X 2012/04 [Not refereed][Not invited]
     
    To determine the effects of CO2 under different atmospheric pressures, we assessed the effects of elevated CO2 on the growth of spring wheat (Triticum aestivum L.) in a field experiment in Lhasa (3688 m above sea level), the Tibet Plateau, China, and in a growth chamber (GC) experiment in Sapporo (15 m above sea level), Japan. Open-top chambers (OTCs) were installed at Lhasa and spring wheat was grown under CO2 at a partial pressure of 23.4 Pa (ambient CO2) and 38.5 Pa (elevated CO2, equivalent to a 200 mu mol mol(-1) increase). In the OTC experiments, CO2 was elevated with gas-firing equipment and a blower, so that the air temperature inside the OTC for elevated CO2 was raised 0.8 degrees C. In the GC experiment in Sapporo, we used three CO2 partial pressure levels; 24.8, 39.8 and 59.3 Pa and two air temperature regimes, 11/19 degrees C and 11/21 degrees C (night/day). In the OTC experiment, dry weight at harvest was lower in the elevated CO2 than in the ambient CO2. In the GC experiment, the effect of the elevation of CO2 from 24.8 to 39.8 Pa on biomass was greater than that from 39.8 to 59.3 Pa. A 2 degrees C increase in temperature reduced dry weight at all CO2 levels and offset the positive effect of CO2 increase from 39.8 to 59.3 Pa. The difference between the results obtained in the experiments in OTC and GC was not clear and might have involved artifacts such as blower and/or ethylene effects.
  • Hiroshi Uchino, Kazuto Iwama, Yutaka Jitsuyama, Keiko Ichiyama, Eri Sugiura, Toshiko Yudate, Satoshi Nakamura, Jai Gopal
    FIELD CROPS RESEARCH 127 9 - 16 0378-4290 2012/02 [Not refereed][Not invited]
     
    Interseeding cover crops is an alternative to laborious intertillages and hand weeding followed in organic farming. The objective of this study was to evaluate the effect of fertilization and interseeding cover crops on the growth of main crops and weeds and the stability of weed suppression over years and main crop species under four-year rotational organic farming. Two cover crops, winter rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth), were interseeded in furrows of potato (Solarium tuberosum L.), soybean (Glycine max Merr.) and maize (Zea mays L.) at 3-5 weeks after planting the main crops. The number and dry weight of weeds were measured at the maximum plant height stage of main crops and main crop yields were recorded at their physiological maturity. The light competition between main crops, cover crops and weeds was analyzed by vertical community structure and vegetation cover ratio (VCR) of each crop. Since light competition of main crops with cover crops and weeds was not severe, main crop yields were not suppressed significantly by either cover crops or weeds. Weed growth was suppressed significantly by interseeding cover crops through increasing the VCR of main crops plus cover crops. This weed suppression by interseeding cover crops was stable to the main crop species in rotational cropping systems and to the various environmental conditions, because the cover crops compensated the low VCR of main crops alone at early growth stage especially when main crop growth was depressed by unfavorable environmental conditions. In addition, input of compost and fermented organic fertilizer had positive effects on the main crop yield and weed suppression. It is concluded, therefore, that weeds can be suppressed effectively and stably without yield reductions of main crops by interseeding cover crops with sufficient fertilization in organic farming systems. (C) 2011 Elsevier B.V. All rights reserved.
  • Yutaka Jitsuyama, Shinji Ichikawa
    WEED TECHNOLOGY 25 (3) 454 - 458 0890-037X 2011/07 [Refereed][Not invited]
     
    Cryogens are defined as substances that produce low temperatures. In this study, cryogens refer to salts added to snow or ice to cool underlying soil, resulting in reduced weed establishment. In laboratory experiments, bags of ice mixed with cryogens were able to reach temperatures as low as -17 C. In soil-filled pots stored at 4 C, bags of cryogenic salts filled with ice chips reduced the soil temperatures to below 0 C and reduced the establishment of weeds significantly without salinity effects. The cryogen magnesium chloride-6-hydrate (MC) that was effective in pot experiments was tested in an oat field in 2008 and 2009. Plastic bags containing concentrated solutions of MC, perforated at the top, were placed on bare soil just before snowfall. Contact of snow with MC was expected to decrease the surface soil temperature enough to cause freezing injury to seeds in the soil. Although overall effects on weed establishment were small, the cryogenic effect did significantly reduce corn spurry establishment in 2008, and significantly reduced overall weed establishment in both years. These results show that weed management with cryogenic salts is possible in principle, but requires further technical improvements to be practical in the field.
  • Hiroshi Uchino, Akihiko Tago, Kazuto Iwama, Yutaka Jitsuyama, Yuji Hirayama, Kazuo Tanaka
    PLANT PRODUCTION SCIENCE 14 (2) 96 - 104 1343-943X 2011/04 [Not refereed][Not invited]
     
    Consumer demand for good eating quality of cooked rice has been growing widely not only in Japan but also in other countries. Eating quality of the non-glutinous rice varieties bred in Hokkaido, northern Japan, during the past 20 years has improved drastically due to the breeding efforts focused mainly on chemical properties, such as amylose and protein concentrations. However, the effect of physical properties, such as cell morphology, on eating quality has been less studied. To clarify the relationship between physical properties and eating quality of rice, we investigated endosperm cell morphology (ECM) of grain by using a new simple method with a stereomicroscope for 18 non-glutinous varieties released over the past 100 years in Hokkaido. There were significant varietal differences in most of the ECM characteristics measured. Especially, cell density along the central line of endosperm (CLE) correlated negatively with the released year of varieties (r = -0.827, p < 0.001), and decreased with the decrease in amylose and protein concentrations. The results indicated that the rice breeding in Hokkaido has changed not only the chemical but also physical properties. In addition, some varieties with similar amylose and protein concentrations showed large differences in CLE cell density. This suggests that the varietal difference in eating quality, which can not be explained by the difference in amylose and protein concentrations only, may be explained by the difference in CLE cell density. These findings will contribute to the further improvement in eating quality of non-glutinous rice.
  • Hiroshi Uchino, Kazuto Iwama, Yutaka Jitsuyama, Keiko Ichiyama, Eri Sugiura, Toshiko Yudate
    PLANT PRODUCTION SCIENCE 14 (1) 75 - 85 1343-943X 2011/01 [Not refereed][Not invited]
     
    The use of cover crops is an effective technique to control weeds, which are one of the most serious problems for crop production without using herbicides. This study investigated the characteristics of cover crops for weed suppression at an organic farming field in a snowy-cold region, Hokkaido. Nine, three and two species of cover crops comprising both Poaceae and Leguminosae were grown in 2003, 2004 and 2005, respectively, at different sowing densities from 50 to approximately 4000 seeds m(-2). The relationships between weed dry matter production and characteristics of cover crops, such as plant height and coverage, were investigated at 4 and 10 weeks after cover crop sowing (WAS). Correlation analysis of the weed dry weight with characteristics of cover crops revealed that the cover crop coverage at 4 WAS had a strong and stable effect on weed suppression. The cover crop coverage at 4 WAS was affected primarily by their seed weight when cover crops with a large variation in seed weight were used, and by the sowing density when cover crops with a small variation in seed weight were used. These results suggest that to achieve high weed suppression it is important to obtain higher coverage at the early growth stage of the cover crops with a heavy seed weight and high sowing density.
  • Shigeto Fujimura, Peili Shi, Kazuto Iwama, Xianzhou Zhang, Jai Gopal, Yutaka Jitsuyama
    PLANT PRODUCTION SCIENCE 13 (2) 141 - 149 1343-943X 2010/04 [Not refereed][Not invited]
     
    The partial pressure of CO2 in air decreases with the increase in altitude. Therefore, increase in molar concentration of CO2 is smaller at higher altitudes than at lower altitudes for increases in molar fraction of CO2. This study aimed to predict the effect of global CO2 increase on net photosynthetic rate of spring wheat (Tritium aestivum L.) at high altitudes. The net photosynthetic rate of spring wheat grown in Lhasa (3688 in above sea level), China, was compared with that of the same cultivar grown in Sapporo (15 m above sea level), Japan. At the current level of CO2, it was significantly lower in Lhasa than in Sapporo, and stomatal conductance, chlorophyll content (SPAD value) and apparent quantum yield were similar in both locations. The interaction of CO2 level and altitude was suggested; the amount of increase in net photosynthetic rate caused by increase in CO2 was smaller at high altitudes than at low altitudes. Lower CO2 partial pressure at higher altitude could explain the difference in net photosynthetic rate between altitudes, and the interaction of CO2 level and altitude.
  • ANZOUA KOSSONOU GUILLAUME, JUNICHI KASHIWAGI, TOSHIHIRO HASEGAWA, KAZUTO IWAMA, YUTAKA JITSUYAMA
    Field Crop Res 116 (1-2) 38 - 45 0378-4290 2010/03/03 [Not refereed][Not invited]
  • Kossonou Guillaume Anzoua, Kashiwagi Junichi, Hasegawa Toshihiro, Iwama Kazuto, Jitsuyama Yutaka
    FIELD CROPS RESEARCH 116 (1-2) 38 - 45 0378-4290 2010/03 [Not refereed][Not invited]
     
    Eight rice cultivars released in 1905, 1919, 1941, 1954, 1971, 1984, 1987 and 1988 were investigated to identify the traits that contributed to high yield and low soil nitrogen tolerance breeding under cold environment. They were grown in fields at three different nitrogen (N) fertilizer treatments, 0, 6 and 12 g N m(-2) (0 N, 6 N and 12 N) in Sapporo, Northern Japan, in 2001 and 2002. All cultivars; increased their grain yield (GY) with the increase in soil N availability, and better response to N was observed in modern cultivars; released during 1984-1988 compared to old ones (1905-1954). Irrespective of N treatments, the modern cultivars showed better GY than the older ones. Absolute genetic gain was 2.15 or 2.94 g m(-2) year(-1) at 6 N and 12 N. Under 0 N treatment, although the magnitude of yield increase was small, the genetic gain in GY was still observed at 0.78 g m(-2) year(-1). The GY increments were achieved mainly through increasing the number of spikelets (SPK) which depends on the number of panicle (PAN) at any level, and the PAN could be increased by enhancing the number of tillers. The extinction coefficient (k) showed that the older cultivars had a spreading plant type, on the other hand, the modern cultivars had an erect plant type which seemed to be a better plant structure in terms of light distribution. This change on plant structure would allow the modern cultivars to have a larger LAI with improved light capturing resulting in better GY in modern cultivars; than the old cultivars having similar LAI with modern cultivars. These breeding strategies could work for the high-yielding rice breeding program under cold environments irrespective of soil nitrogen conditions. (C) 2009 Elsevier B.V. All rights reserved.
  • Yutaka Jitsuyama, Akihiko Tago, Chiharu Mizukami, Kazuto Iwama, Shinji Ichikawa
    AMERICAN JOURNAL OF POTATO RESEARCH 86 (6) 430 - 441 1099-209X 2009/11 [Not refereed][Not invited]
     
    Fresh potato tubers of 13 different cultivars were analyzed for endogenous components and morphological traits in intact cells to study the relationship between traits of fresh tubers and the flavor of cooked (steamed) potato. Deliciousness composed of sweetness, potato taste and smoothness was significantly different between the cultivars; the tasting evaluations were reasonable when considering each tuber utilization, i.e. deliciousness of vegetable potato tended to be higher than that of the others, potato for processing and starch. The three main tasting traits were each related significantly, particularly potato taste had strong-negative correlation with sweetness and smoothness of tuber. The main tasting traits also had strong relationships to the starch content in cortex tissue of potato tubers. The starch content was significantly related negatively to potassium, phosphorus and cell size of cortex and they were related positively to smoothness of steamed tuber. The sweetness of steamed tuber was related negatively to the starch content, and the pH of the extract solution from cortex tissue was related significantly to both traits, sweetness and starch content. The potato taste of steamed tubers was related positively to starch content, but sweetness was significantly related negatively to potato taste by the physical traits of cortex tissue, pulp hardness and strength of cell wall binding. Thus, complicated flavor-linkages pivoting on starch through endogenous component and pH seemed to influence the deliciousness of steamed tubers, but traits that had no relation with starch content were also detected, such as silicon content. These results of this study may be useful for breeding potato cultivars with Japanese desirable flavor traits for use as vegetables.
  • JITSUYAMA YUTAKA, TAGO AKIHIKO, MIZUKAMI CHIHARU, MIZUKAMI CHIHARU, IWAMA KAZUTO, ICHIKAWA SHINJI
    Am J Potato Res 86 (6) 430 - 441 1099-209X 2009/11 [Not refereed][Not invited]
  • Xu Zheng, Yutaka Jitsuyama, Takayoshi Terauchi, Kazuto Iwama
    PLANT PRODUCTION SCIENCE 12 (4) 449 - 452 1343-943X 2009/10 [Not refereed][Not invited]
     
    Most Studies oil non-structural carbohydrate (NSC) are concentrated on the leaf and tuber, and little is known about NSC in the stern and its function. To test the hypothesis that, NSC Stored in stern contributes to stable tuber bulking under stress conditions, we grew plants in pots in a greenhouse Under drought and shading Conditions for 17 d during tuber bulking. Compared with the Control, drought and shading significantly reduced leaf and stein dry weights (DW) and total NSC concentration in the main stem base. However, tuber DW increased by 77% in drought, and by 46% in shading conditions relative to the control. The contributions of NSC loss in the stern to tuber DW increase in drought. and shading conditions were 37% and 54%, respectively This Study suggests that NSC stored in the stein base is supplied to tuber under stress conditions to Support tuber bulking.
  • Xu Zheng, Yutaka Jitsuyama, Takayoshi Terauchi, Kazuto Iwama
    PLANT PRODUCTION SCIENCE 12 (4) 449 - 452 1343-943X 2009/10 [Not refereed][Not invited]
     
    Most Studies oil non-structural carbohydrate (NSC) are concentrated on the leaf and tuber, and little is known about NSC in the stern and its function. To test the hypothesis that, NSC Stored in stern contributes to stable tuber bulking under stress conditions, we grew plants in pots in a greenhouse Under drought and shading Conditions for 17 d during tuber bulking. Compared with the Control, drought and shading significantly reduced leaf and stein dry weights (DW) and total NSC concentration in the main stem base. However, tuber DW increased by 77% in drought, and by 46% in shading conditions relative to the control. The contributions of NSC loss in the stern to tuber DW increase in drought. and shading conditions were 37% and 54%, respectively This Study suggests that NSC stored in the stein base is supplied to tuber under stress conditions to Support tuber bulking.
  • H. Uchino, K. Iwama, Y. Jitsuyama, T. Yudate, S. Nakamura
    FIELD CROPS RESEARCH 113 (3) 342 - 351 0378-4290 2009/09 [Not refereed][Not invited]
     
    Weed management is a major issue inorganic farming systems. Although interseeding cover crops is one alternative to herbicides, cover crops often suppress not only weeds but also main crops. Therefore, using cover crops for weed control without adverse effects on main crop growth is important. To verify the effect of covercrops on competition between main crops, cover crops and weeds in a snowy-cold region, main crops soybean (Glycine max Merr.) in 2005 and maize (Zea mays L.) in 2006 were grown with cover crops winter rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth), respectively. The cover crops were sown on three sowing dates: before main crop planting (Pre-MC), on the same date of main crop planting (Syn-MC) and after main crop planting (Post-MC). A plot without cover crops (Sole-MC) was used as a control. The dry weight (DW), vegetation cover ratio (VCR), vertical community structure and chlorophyll content were measured to estimate the competition between main crops, cover crops and weeds. Weed DW was suppressed significantly by sowing cover crops in both soybean and maize. This weed suppression was associated with the increase of VCR of main crops plus cover crops at the early growth stage of main crops. Soil seed banks of dominant weed also became lower by sowing cover crops, implying the importance of proper weed management for suppressing weeds successively. In addition, the sowing dates of cover crops had large effects on main crops DW especially in maize, i.e., it was significantly lower in Pre-MC and Syn-MC than in Post-MC. Although the cover (:top height was markedly shorter than the main crop height, the chlorophyll content of the main crops was significantly lower when cover crops were sown earlier. These results suggest that the growth inhibition of main crops by cover crops was partly caused by competition for nutrients between main crops and cover crops, and this growth inhibition was alleviated when cover crops were sown after the establishment of main crops. Consequently, soybean yield was the highest in Post-MC and decreased by 29%, 18% and 7% in Sole-MC, Pre-MC and Syn-MC, respectively, and maize yield was also the highest in Post-MC and decreased by 68%, 100% and 24% in Sole-MC, Pre-MC and Syn-MC, respectively. It was concluded that weeds could be controlled effectively by sowing cover crops after planting main crops in organic farming systems in a snowy-cold region. (C) 2009 Elsevier B.V. All rights reserved.
  • Shigeto Frijimura, Peili Shi, Kazuto Iwama, Xianzhou Zhang, Jai Gopal, Yutaka Jitsuyama
    PLANT PRODUCTION SCIENCE 12 (1) 116 - 123 1343-943X 2009/01 [Not refereed][Not invited]
     
    The Tibetan Plateau is one of the highest cultivated regions in the world. The objective of the present study was to compare wheat growth and grain Odd in We high altitude region with those in a low altitude region. Two spring wheat. cultivars wow grown for two years at an experimental field in Lhasa (29 degrees N, 3688 m above sea level in the Tibetan Plateau in 2001 and 2003 and in Sapporo (43 degrees N, 15 m above sea level), Japan in 2002 and 2003. In Lhasa, temperature throughout the growth period was lower and photoperiod before heading was shorter than in Sapporo. There was no significant difference in grain yield between Lhasa and Sapporo. Dry Matter production) was higher in Lhasa than in Sapporo. The crop growth line before heading was similar in both locations, but Me time to heading was 15 days longer in Lhasa than in Sapporo. I oaf senescence inn more decelerated ill Lhasa than in Sapporo. These results suggested that high dry matter production in Lhasa was mainly Clue to the longer growth period.
  • Katashi Kubo, Hiroshi Uchino, Yutaka Jitsuyama, Kazuto Iwama
    PLANT PRODUCTION SCIENCE 11 (4) 487 - 497 1343-943X 2008/10 [Not refereed][Not invited]
     
    Root growth into deep soil is an important factor for stable production in wheat under drought conditions. Root penetrating capcity (RP) shown by pot experiments with a parffin-Vaseline layer (PV layer) may be auseful indicator estimating deep rooting ability of wheat genotypes. Previously, we identified genotypes of durum wheat (Triticum turgidum L. var. durum) and bread wheat (T. aestivum L.) with diverse RP by the pot experiments. In this study, we investigated the root distribution of three Ethiopian landraces of durum wheat with high RP, three rcent cultivars of durum wheat with low RP and one Japanese cultivar of bread wheat 'Haruyutaka' with low RP using: (1) pots with a PV layer, (2) root boxes, (3) artificial field and (4) a normal field to analyze the relationship between RP estimated by pot experiment and root development in the field. In the pot experiments, RP was evaluated by the number of roots penetrating through the PV layer (NRP). In the root-box and field experiments, the root number cm-1 soil surface). Ethiopian landraces had a significantly larger NRP than recent cultivars in the pot experiment. The root box and field experiments showed that Ethiopian landereaces tended to have a higher RF than recent cutivars in deep soil layer. We concluded that RP estimated by pot experiments with a PV layer is a usful indicator of deep rooting ability under field conditions.
  • J. Gopal, K. Iwama, Y. Jitsuyama
    IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY-PLANT 44 (3) 221 - 228 1054-5476 2008/06 [Not refereed][Not invited]
     
    With the objective to develop a practical method of screening potato for drought tolerance, shoot and root growth in plantlets raised in vitro (from nodal cuttings drawn from in vivo as well as in vitro grown plantlets) were studied in three genotypes with known root mass production under field conditions. Different levels of water stress were induced using five concentrations of agar in MS (Murashige and Skoog in Physiol Plant 15:473-497, 1962) medium. Water potential of various media ranged from -0.70 MPa to -0.98 MPa. Water stress in culture adversely affected plantlet growth, and the responses varied with genotype and explant source. Genotype IWA-1 was less affected than Konafubuki and Norin-1. In the experiment with explants from in vivo grown plants, the time to rooting was considerably delayed in Konafubuki and Norin-1 by an increase in agar concentration, but no such effect was observed in IWA-1. In all media, the mean number of roots and root length was greater in IWA-1 than Konafubuki and Norin-1, and the latter two genotypes were at par. At 10 gl(-1) agar, IWA-1 had taller plantlets, heavier foliage dry weight, root volume, as well as root dry weight than Konafubuki and Norin-1, whereas the latter two genotypes were at par for all these characteristics. This pattern was similar to the reported pattern of these genotypes for root dry weight under field conditions. However, such similarity in the in vitro and field behavior of the tested genotypes was not observed when nodal cuttings drawn from in vitro plantlets were used as explants. It is concluded that in vitro screening of potato under specific and limited water stress conditions by raising plantlets from nodal cuttings drawn from in vivo grown plants may provide a system for effectively differentiating the genotypes for their expected root mass production under field conditions.
  • Genotypic variation of the ability of root to penetrate hard soil layers
    Plant Breeding 126 (4) 375 - 378 2007 [Not refereed][Not invited]
  • KUBO K.
    Plant Breed. 126 (4) 375 - 378 0179-9541 2007 [Refereed][Not invited]
  • Minehiko Fukuoka, Kazuto Iwama, Yutaka Jitsuyama
    Japanese Journal of Crop Science 日本作物學會 75 (1) 57 - 67 0011-1848 2006 [Not refereed][Not invited]
     
    The difference (ΔT) between canopy temperature (Tc) and air temperature (Ta) was examined for its validity as a criterion for drought avoidance in upland rice under field conditions in Japan, where vapor pressure deficit is low. The varieties which were assumed to differ greatly in drought avoidance mainly because of the difference in root depth, were grown in fully irrigated field plots (FIFP) and non-irrigated field plots (NIFP) in 2001, and in NIFP in 2002, under a rain shelter. On six dates during one month until heading in each year, Tc, Ta and stomatal conductance (gs) were measured nearly simultaneously using infrared thermography, thermometer and porometer, respectively. Root depth was measured at the harvest in 2002. In 2001, the rank order of ΔT averaged for all the dates (the cooler the higher) corresponded to that of gs (the higher the higher) among varieties within the same irrigation scheme. However, the rank order of ΔT and gs in FIFP did not correspond to that in NIFP which represents the degree of drought avoidance. In 2002, ΔT on each of the dates and the average for all the dates differed significantly among varieties. The deeper the roots, the higher the gs and the lower the ΔT. These results indicate that ΔT in NIFP can be utilized as a criterion for drought avoidance in upland rice under field conditions in Japan.
  • K Kubo, K Iwama, A Yanagisawa, Y Watanabe, T Terauchi, Y Jitsuyama, T Mikuma
    PLANT PRODUCTION SCIENCE 9 (1) 47 - 55 1343-943X 2006/01 [Not refereed][Not invited]
     
    The hard soil in the field is a major constraint for the cereal production because it mechanically restricts the root expansion and water absorption. The ability of root to penetrate into the hard soil is an important factor affecting yield stability of wheat (Triticum aestivum, L.) under hard soil and drought conditions. We investigated the variation in the penetrating ability of roots (PA) among Japanese wheat cultivars and its relationship with other shoot and root characters to acquire basic information to develop the cultivars With a higher PA. The evaluation was conducted by the two experiments using the two groups of cultivars: 1) 43 Hokkaido cultivars in the first experiment, 2) 38 Honsyu, including Shikoku and Kyusyu, cultivars in the second experiment. In each experiment, one seedling of each cultivar was grown in a pot with a disc made of paraffin and Vaseline mixture (PV) as a substitute for the hard soil layer. The number of roots penetrating through the PV disc per plant (NRP), the number of seminal and crown roots reached the PV disc per plant (NRR) and the penetration index (PI = NRP/NRR) of each cultivar were evaluated as the traits related to PA. NRP significantly varied with the cultivar from 4.0 to 29.7 and 3.0 to 22.0 in the first and second experiments, respectively. NRP were significantly correlated with NRR (r=0.644** in the first and r=0.477**: in the second experiment) and PI (r=0.863** in the First and r=0.811** in the second experiment), but the relationships between NRR and PI were not significant (r=0.260 in the first and r=0.190 in the second experiment). NRR was significantly correlated with the degree of winter growth habit (requirement of vernalization), root dry weight (DW) above the PV disc, the number of steins and leaf DW in each population. Correlations between PI and other characters were low or not significant. These results indicate that a large genotypic variation exists among Japanese wheat cultivars in NRP, and that PI is a suitable indicator of PA. Cultivars with a high PA detected in this study will be useful genetic resources of wheat to improve the yield stability under drought and hard soil conditions.
  • J Kawakami, K Iwama, Y Jitsuyama
    FIELD CROPS RESEARCH 95 (1) 89 - 96 0378-4290 2006/01 [Not refereed][Not invited]
     
    Tuber yields of potato plants grown from microtubers in fields are more variable than yields from conventional seed tubers (CT). One reason could be their higher susceptibility to water stress. This study clarified the effect of soil water stress from I month after emergence on the growth and yield of plants grown from conventional seed tubers and microtubers in fields. Microtubers (0.5-3 g) and conventional seed tubers (50 g) were grown in Hokkaido, Japan, over three field seasons. One month after emergence, polyshelters were placed over the plots to prevent rainfall, and either irrigated (wet plot) or non-irrigated (dry plot) treatments were formed. At mid-flowering (about 50 days after emergence) leaf area index (LAI) in microtuber plants was decreased relatively more due to soil water stress than LAI in conventional seed tuber plants. However, at maximum shoot growth (about 80 days after emergence) both microtuber and conventional seed tuber plants had a similar relative decrease in LAI due to soil water stress. At mid-flowering and maximum shoot growth microtuber and conventional seed tuber plants had reduced stomatal conductance due to soil water stress, but the reduction in stomatal conductance was greater in conventional seed tuber plants than in microtuber plants. Microtuber and conventional seed tuber plants had similar root development at maximum shoot growth. Tuber production from midflowering until plant maturity was similarly affected by soil water stress in microtuber and conventional seed tuber plants. At harvest, plants affected by soil water stress had about 87% of the tuber dry weight of irrigated plants. We conclude, that the greater variation on tuber yield of microtuber plants cannot be attributed to soil water stress from 1 month after emergence. (c) 2005 Elsevier B.V. All rights reserved.
  • K Kubo, K Iwama, A Yanagisawa, Y Watanabe, T Terauchi, Y Jitsuyama, T Mikuma
    PLANT PRODUCTION SCIENCE 9 (1) 47 - 55 1343-943X 2006/01 [Not refereed][Not invited]
     
    The hard soil in the field is a major constraint for the cereal production because it mechanically restricts the root expansion and water absorption. The ability of root to penetrate into the hard soil is an important factor affecting yield stability of wheat (Triticum aestivum, L.) under hard soil and drought conditions. We investigated the variation in the penetrating ability of roots (PA) among Japanese wheat cultivars and its relationship with other shoot and root characters to acquire basic information to develop the cultivars With a higher PA. The evaluation was conducted by the two experiments using the two groups of cultivars: 1) 43 Hokkaido cultivars in the first experiment, 2) 38 Honsyu, including Shikoku and Kyusyu, cultivars in the second experiment. In each experiment, one seedling of each cultivar was grown in a pot with a disc made of paraffin and Vaseline mixture (PV) as a substitute for the hard soil layer. The number of roots penetrating through the PV disc per plant (NRP), the number of seminal and crown roots reached the PV disc per plant (NRR) and the penetration index (PI = NRP/NRR) of each cultivar were evaluated as the traits related to PA. NRP significantly varied with the cultivar from 4.0 to 29.7 and 3.0 to 22.0 in the first and second experiments, respectively. NRP were significantly correlated with NRR (r=0.644** in the first and r=0.477**: in the second experiment) and PI (r=0.863** in the First and r=0.811** in the second experiment), but the relationships between NRR and PI were not significant (r=0.260 in the first and r=0.190 in the second experiment). NRR was significantly correlated with the degree of winter growth habit (requirement of vernalization), root dry weight (DW) above the PV disc, the number of steins and leaf DW in each population. Correlations between PI and other characters were low or not significant. These results indicate that a large genotypic variation exists among Japanese wheat cultivars in NRP, and that PI is a suitable indicator of PA. Cultivars with a high PA detected in this study will be useful genetic resources of wheat to improve the yield stability under drought and hard soil conditions.
  • J Kawakami, K Iwama, Y Jitsuyama
    PLANT PRODUCTION SCIENCE 8 (1) 74 - 78 1343-943X 2005/03 [Not refereed][Not invited]
     
    This study clarified the effect of planting date on the growth and yield of potato (Solannum tuberosum L.) plants grown from conventional seed tubers (CT) and microtubers (MT). CT of about 50 g and MT of 1 to 3 g of early (Kitaakari) and late (Norin 1) maturity cultivars were planted at Hokkaido University, Sapporo, Japan, on May 13, June 4 and June 25, and their growth and yields were investigated. The linear increase in leaf area index started later, but thereafter was higher in MT plants than in CT plants, irrespective of cultivar and planting date. Tuber formation was later in MT plants than in CT plants of both cultivars, but this difference was smaller on the last planting date. The linear increase in tuber dry weight started later in MT plants than in CT plants, but the rate of increase was similar in NIT and CT plants of both cultivars and on all planting dates. Delaying the date of planting reduced the tuber yield, mainly because of the shortening growing period in MT and CT plants. The reduction in tuber yield and growing period was greater for the late cultivar Norin 1 compared with the early cultivar Kitaakari of CT and MT plants. Despite the climatic variations among the planting dates, MT plants yielded 71 to 90% of tuber fresh weight relative to CT plants, suggesting that MT are a good alternative as propagules for potato cultivation in countries where seed production is difficult.
  • K Kubo, Y Jitsuyama, K Iwama, N Watanabe, A Yanagisawa, Elouafi, I, MM Nachit
    EUPHYTICA 141 (1-2) 105 - 111 0014-2336 2005 [Not refereed][Not invited]
     
    Root penetration (RP) ability into compacted soil is an important breeding target for drought avoidance by durum (Triticum turgidum L. var. durum) and bread wheat (T aestivum L.) in regions with compacted soils and water deficits. However, it is said generally that yield of the current cultivars introduced the reduced height gene (Rht-Blb or Rht-Dlb) are more sensitive to drought stress than that of old landraces. This study investigated the effect of the Rht genes on RP ability using the seedlings of near-isogenic lines (NILs) of Rht genes of 'LD222' durum wheat and 'April Bearded' bread wheat, and 110 recombinant inbred lines (RILs) of durum wheat derived from the cross between the tall landrace (Jennah Khetifa; Rht-Bla Rht-Bla) and semi-dwarf cultivar (Cham1; Rht-Blb Rht-Blb). One seedling of each genotype was grown in a pot (6 cm diameter, 15 cm height) with a disc of 3 mm thickness made from paraffin and Vaseline mixture (PV) in 10 cm depth, as a substitute for a compacted soil layer. The RP index [number of roots penetrating through the PV disc per plant (PVRN)/total number of seminal and crown roots per plant (TRN)] was measured at eight weeks after sowing and used as the indicator of RP ability of seedling. In NILs, the shoot length decreased significantly because of the introduction of either Rht-Blb or Rht-Dlb dwarfing genes, but the RP index was similar to those of tall parents. In RILs, although the RP index and shoot length were higher in Jennah Khetifa than in Cham1, the relationship between RP index and shoot length was not significant (r = 0.156). Both results indicate that RP ability of wheat does not link to dwarfness regulated by Rht genes. We suppose therefore that it would be possible to develop a high yielding semi-dwarf cultivar with excellent RP ability.
  • J Kawakami, K Iwama, Y Jitsuyama, Zheng, X
    AMERICAN JOURNAL OF POTATO RESEARCH 81 (5) 327 - 333 1099-209X 2004/09 [Not refereed][Not invited]
     
    Potato plants of early cultivars grown from microtubers have been reported to have a much lower growth vigor and produce lower yields than microtubers of late cultivars. This study intended to clarify the field performance of plants grown from directly planted microtubers of cultivars with different maturity periods, with a special attention to early cultivars. The experiments were conducted at Hokkaido University, Japan, over four years. Microtubers and conventional seed tubers of the early cultivar Kitaakari, late cultivars Konafubuki and Norin 1, and very late breeding line IWA-1 were planted, and the plant growth and tuber yields were analyzed. The microtuber plants of Kitaakari had a lower initial increase in leaf area index than conventional seed tuber plants, but at the maximum shoot growth had the same leaf area index. This pattern was also observed in the other cultivars. Tuber initiation and tuber bulking occurred on average five days later in microtuber plants than in conventional seed tuber plants of cultivar Kitaakari. At maximum shoot growth, microtuber plants had on average 65% of tuber dry weight of conventional seed tuber plants, with small variation among cultivars. Irrespective of maturity period, microtuber plants showed a higher tuber increase after maximum shoot growth, achieving around 86% of tuber dry weight of conventional seed tuber plants at harvest. From the results of this study we conclude that microtuber plants of early and late cultivars have a similar yield potential relative to conventional seed tuber plants, and microtubers of both early and late cultivars might be used as an alternative seed tuber source for potato production, if necessary.
  • K Kubo, Y Jitsuyama, K Iwama, T Hasegawa, N Watanabe
    PLANT AND SOIL 262 (1-2) 169 - 177 0032-079X 2004/05 [Not refereed][Not invited]
     
    Improvement of root penetration (RP) ability in durum wheat (Triticum turgidum L. var. durum) is an important breeding target to reduce yield losses due to soil compaction and drought. This study investigated the genotypic difference of RP ability in durum wheat of seven Ethiopian landraces (ET genotypes), which were presumed to adapt to soil compaction, and 17 genotypes bred in North America (NA genotypes). The pregerminated seed was planted in a pot with four paraffin-Vaseline (PV) discs of hardness 0.12, 0.24, 0.50 and 0.73 MPa. After eight weeks from planting, each plant was sampled and the number of roots penetrating through the PV discs was counted. No genotype penetrated through the PV disc of 0.73 MPa hardness. The number of roots penetrating through the PV disc of 0.50 MPa hardness showed a significant difference among the genotypes: highest in an ET genotype and lowest in a NA genotype. The mean value was also significantly higher in ET genotypes than in NA genotypes, and it significantly correlated with root weight density below the disc and plant height. The mean root diameter and root weight density above the disc showed no significant difference between NA and ET genotypes. Our results indicate that a large genotypic difference exists for RP ability in durum wheat, and that ET genotypes have a higher RP ability than NA genotypes.
  • J Kawakami, K Iwame, T Hasegawa, Y Jitsuyama
    AMERICAN JOURNAL OF POTATO RESEARCH 80 (6) 371 - 378 1099-209X 2003/11 [Not refereed][Not invited]
     
    Despite many reports of the in vitro production of microtubers, little is known about plant growth and yield from microtubers planted in the field. This study clarified differences in growth and yields between potato plants grown in the field from microtubers and from conventional seed tubers. The experiments were performed at Hokkaido University, Japan, over four years. Conventional seed tubers of about 50 g and microtubers of two sizes (0.5-1.0 g and 1.0-3.0 g) of the late-maturity cultivar Norin 1 were planted, and plant growth and tuber yields were analyzed. The microtuber plants had a lower initial increase in root and leaf area index than conventional seed tuber plants, but had the same leaf area index after about 40 days from emergence. The first tuber formation in microtuber plants was about 7 days later than in conventional seed tuber plants, while tuber bulking occurred about 14 days later in microtuber plants. Consequently, the onset of tuber weight increase was later in microtuber plants, but the rate of increase thereafter was similar between conventional seed tuber and microtuber plants. At harvest the tuber fresh weight of microtuber plants was 82% that of conventional tuber plants, suggesting a potential for using microtubers for field planting.
  • Minehiko Fukuoka, Hideo Tani, Kazuto Iwama, Toshihiro Hasegawa, Yutaka Jitsuyama
    Japanese Journal of Crop Science 日本作物學會 72 (4) 461 - 470 0011-1848 2003 [Not refereed][Not invited]
     
    The difference between canopy temperature and air temperature (ΔT) is reported to be a convenient criterion for the non-destructive evaluation of drought avoidance of crop varieties under field conditions in arid countries, where vapor pressure deficit (VPD) is high. We examined its validity under field conditions in Japan, where VPD is low. We defined the drought avoidance as the ability to maintain stomatal conductance (gs) and leaf water potential (LWP) under non-irrigated conditions as high as those under fully irrigated conditions. Four crops (sugar beet, potato and two rice genotypes of upland and lowland), which were assumed to be greatly different in drought avoidance, were grown in both fully irrigated and non -irrigated fields under a rain shelter. For five weeks starting from the 7th week after planting, ΔT was measured by infrared thermography, in concurrence with the measurement of gs and LWP. In the non-irrigated plot, ΔT, gs and LWP differed significantly among the crops lowland rice showed the highest ΔT and the lowest gs and LWP, followed by upland rice, potato and sugar beet. Meanwhile, in the irrigated plot, their differences were relatively small. There was significant interaction between irrigation treatment and crop in ΔT, gs and LWP (all p < 0.001). These results indicate that the difference in drought avoidance among crops can be evaluated under field conditions in Japan, using ΔT under non-irrigated conditions.
  • T Yamada, K Kuroda, Y Jitsuyama, D Takezawa, K Arakawa, S Fujikawa
    PLANTA 215 (5) 770 - 778 0032-0935 2002/09 [Refereed][Not invited]
     
    In an effort to clarify the responses of a wide range of plant cells to freezing, we examined the responses to freezing of the cells of chilling-sensitive and chilling-resistant tropical and subtropical plants. Among the cells of the plants that we examined, those of African violet (Saintpaulia grotei Engl.) leaves were most chilling-sensitive, those of hypocotyls in mungbean [Vigna radiata (L.) R. Wilcz] seedlings were moderately chilling-sensitive, and those of orchid [Paphiopedilum insigne (Wallich ex Lindl.) Pfitz.] leaves were chilling-resistant, when all were chilled at -2 degreesC. By contrast, all these plant cells were freezing-sensitive and suffered extensive damage when they were frozen at -2 degreesC. Cryo-scanning electron microscopy (Cryo-SEM) confirmed that, upon chilling at -2 degreesC, both chilling-sensitive and chilling-resistant plant cells were supercooled. Upon freezing at -2 degreesC, by contrast, intracellular freezing occurred in Saintpaulia leaf cells, frost plasmolysis followed by intracellular freezing occurred in mungbean seedling cells, and extracellular freezing (cytorrhysis) occurred in orchid leaf cells. We postulate that chilling-related destabilization of membranes might result in the loss of the ability of the plasma membrane to act as a barrier against the propagation of extracellular ice in chilling-sensitive plant cells. We also examined the role of cell-walls in the response to freezing using cells in which the plasma membrane had been disrupted by repeated freezing and thawing. In chilling-sensitive Saintpaulia and mungbean cells, the cells with a disrupted plasma membrane responded to freezing at -2 degreesC by intracellular freezing. By contrast, in chilling-resistant orchid cells, as well as in other cells of chilling-resistant and freezing-resistant plant tissues, including leaves of orchard grass (Dactylis glomerata L.), leaves of Arabidopsis thaliana (L.) Heynh. and cortical tissues of mulberry (Morus bombycis Koids.). cells with a disrupted plasma membrane responded to freezing by extracellular freezing. Our results indicate that, in the chilling-sensitive plants cells that we examined. not only the plasma membrane but also the cell wall lacked the ability to serve as a barrier against the propagation of extracellular ice, whereas in the chilling-resistant plant cells that we examined, not only the plasma membrane but also the cell wall acted as a barrier against the propagation of extracellular ice. It appears. therefore, that not only the plasma membrane but also the cell wall greatly influences the freezing behavior of plant cells.
  • Y Jitsuyama, T Suzuki, T Harada, S Fujikawa
    CRYOLETTERS 23 (2) 103 - 112 0143-2044 2002/03 [Refereed][Not invited]
     
    The freezing tolerance of asparagus (Asparagus officinalis L.) embryogenic cells, as determined by electrolyte leakage, was increased by the incubation of samples in medium containing 0.8 M sucrose. To elucidate the mechanism involved, we investigated the changes in soluble carbohydrates, cell ultrastructure and proteins accompanying the increase in freezing tolerance following incubation in sugar-rich medium, During sugar incubation, the intracellular sucrose content increased from 67 umol.g-1FW to 429 umol.g-1FW it was also metabolized into fructose and glucose, as determined by high- performance liquid chromatography. Microscopy revealed that sugar incubation induced plasmolysis of embryogenic cells and drastic changes in cell ultrastructure with the appearance of rough endoplasmic reticulum (rER). Furthermore, immunoblotting analysis with anti-dehydrin antiserum revealed that a dehydrin-like protein appeared only when maximal freezing tolerance was induced by sugar incubation. These results suggest that freezing tolerance of asparagus embryogenic cells is increased by a complex mechanism involving notably changes in cell ultrastructure and accumulation of certain sugars and proteins during sugar incubation.
  • Kawakami Jackson, Iwama Kazuto, Hasegawa Toshihiro, Jitsuyama Yutaka, Sugihara Kyohei
    Report of the Hokkaido Branch, the Japanese Society of Breeding and Hokkaido Branch, the Crop Science Society of Japan 日本作物学会 (42) 89 - 90 2001/12
  • Y Jitsuyama, T Suzuki, T Harada, S Fujikawa
    PROTOPLASMA 217 (4) 205 - 216 0033-183X 2001 [Refereed][Not invited]
     
    The freezing tolerance of cabbage petioles and asparagus shoot apexes was increased by preincubation with 0.8 M sugar solutions. In cabbage petioles with an initial freezing tolerance of -3 degreesC (temperature far 50% cell survival), as determined by both electrolyte leakage and fluorescein diacetate vital staining, the freezing tolerance was increased to -13 degreesC by incubation with sorbitol solutions for 3 h. In meristematic cells of asparagus shoot apexes with an initial freezing tolerance of -7.5 degreesC, as determined by fluorescein diacetate vital staining, the freezing tolerance was increased to -30 degreesC by incubation with 0.8 M sugar solutions for 3 h, although other cells in the shoot apexes were killed by higher freezing temperatures. During incubation of both cabbage petioles and asparagus shoot apexes with sugar solutions, sugars were intracellularly taken up by osmotically induced fluid-phase endocytotic vesicles, as indicated by comovement of Lucifer Yellows carbohydrazide (LYCH) observed with a confocal laser scanning microscope. The amounts of intracellularly taken up sugars increased concomitantly with the formation of endocytotic vesicles depending on the time of incubation in parallel with a gradual increase of freezing tolerance. However, the endocytotic vesicles and their contents were retained not only after prolonged incubation after maximum freezing tolerance had been achieved but also after recovery of these tissue cells to isotonic conditions or after freeze-thawing. These results suggest that although sugars are intracellularly taken up by endocytotic vesicles, they might be sequestered within vesicles, casting doubt on their protective role to the plasma membranes as a main site of freezing injury. The pretreatment with 1 mM p-chloromercuribenzenesulfonic acid (PCMBS), an inhibitor of sugar transport, reduced the amounts of intracellular sugar uptake without affecting the formation of endocytotic vesicles, suggesting that sugars were, at least partly, taken up by sugar transporters. In the pretreatment with PCMBS, the freezing tolerance of incubated tissues with sugar solutions was significantly reduced, although addition of PCMBS per se did not affect survival. These results suggest that sugars taken up by sugar transporters, rather than sugars taken up by endocytotic vesicles, are mainly responsible for the increased freezing tolerance of cabbage petioles and asparagus shoot apexes. Furthermore, we aimed to study the occurrence of fluid-phase endocytosis with LYCH in an isotonic condition. Our results indicated that uptake of LYCH by fluid-phase endocytotic vesicles was not detected microscopically in isotonic condition, although LYCH was spectrofluorimetrically taken up in isotonic condition. Spectrofluorimetric uptake of LYCH was inhibited by addition of probenecid, an anion transport inhibitor. These results suggest that in cabbage petioles and asparagus shoot apexes, LYCH is taken up by anion transport but not by fluid-phase endocytosis in isotonic condition, and uptake of LYCH by fluid-phase endocytosis is restricted to occur only in hypertonic condition.
  • Ultrastructural aspects of freezing adaptation of cells by vitrification
    Cryopreservation of tropical plant germplasm -current research progress and application- 36 - 42 2000 [Not refereed][Not invited]
  • YAMADA TOMOYOSHI, KURODA KATSUSHI, JITSUYAMA YUTAKA, FUJIKAWA SEIZO
    低温生物工学会誌 低温生物工学会 45 (2) 92 - 98 1340-7902 1999/12/30 [Not refereed][Not invited]
     
    Freezing behavior of tropical and subtropical plants was examined by means of Cryo-SEM and freeze-fracture replica electron microscopy. Saintpaulia (Saintpaulia grotei mutant) leaf cells and mungbean (Vigna radiatd) seedling cells produced intracellular freezing by inoculate freezing at -2℃, whereas orchid (Paphiopedilum insigne) leaf cells responded to freezing at -2℃ by extracellular freezing. Because chilling treatment (supercooling) at -2℃ did not cause intracellular freezing, intracellular freezing in Saintpaulia and mungbean is suggested to be due to seeding of extracellular ice thorough cells. The relationships between chilling-induced plasma membrane changes and occurrence of intracellular freezing were discussed.
  • S Fujikawa, Y Jitsuyama, K Kuroda
    JOURNAL OF PLANT RESEARCH 112 (1106) 237 - 244 0918-9440 1999/06 [Not refereed][Not invited]
     
    Cold acclimation is a complex adaptive mechanism by which plants survive freezing in winter. During cold acclimation, diverse intracellular and extracellular changes occur. Although most of these changes are related to the acquirement of freezing tolerance, the exact role of these changes in the attainment of freezing tolerance is still unclear. In this review, we suggest the possible role of some of these cold acclimation-induced changes in relation with increased freezing tolerance from the viewpoint of inhibition of freezing injury produced by close approach of membranes.
  • S Fujikawa, K Kuroda, Y Jitsuyama, Y Sano, J Ohtani
    PROTOPLASMA 206 (1-3) 31 - 40 0033-183X 1999 [Not refereed][Not invited]
     
    By cryo-scanning electron microscopy we examined the effects of the organization of the cell walls of xylem ray parenchyma cells on freezing behavior, namely, the capacity for supercooling and extracellular freezing, in various softwood species. Distinct differences in organization of the cell wall were associated with differences in freezing behavior. Xylem ray parenchyma cells with thin, unlignified primary walls in the entire region (all cells in Sciadopitys verticillata and immature cells in Pinus densiflora) or in most of the region (mature cells in P. densiflora and all cells in P. pariflora var. pentaphylla) responded to freezing conditions by extracellular freezing, whereas xylem ray parenchyma cells with thick, lignified primary walls (all cells in Crytomeria japonica) or secondary walls (all cells in Larix leptolepis) in most regions responded to freezing by supercooling. The freezing behavior of xylem ray parenchyma cells in L. leptolepis changed seasonally from supercooling in summer to extracellular freezing in winter, even though no detectable changes in the organization of cell walls were apparent. These results in the examined softwood species indicate that freezing behavior of xylem ray parenchyma cells changes in parallel not only with clear differences in the organization of cell walls but also with subtle sub-electron-microscopic differences, probably, in the structure of the cell wall.
  • Y Jitsuyama, T Suzuki, T Harada, S Fujikawa
    CRYO-LETTERS 18 (1) 33 - 44 0143-2044 1997/01 [Not refereed][Not invited]
     
    Glucose caused increased tolerance to equilibrium slow freezing of cabbage leaf tissues, with a decrease in the temperature for the loss of 50% of electrolytes from -5 degrees C, in untreated controls, to -17 degrees C in samples that had been pre-incubated with 1 M solution of glucose for 10 min, The brief incubation with glucose induced plasmolysis. The increased freezing tolerance of plasmolyzed cells was related to a reduction in the frequency of occurrence of ultrastructural changes in plasma membranes that were produced by the close apposition of membranes, a well characterized cause of freezing injury. It is suggested that reduction in the extent of the close apposition of membranes might be due principally to the mitigation of severe deformation of cell walls during freezing by the presence of glucose in periprotoplasmic spaces.
  • JITSUYAMA YUTAKA, SUZUKI TAKASHI, HARADA TAKASHI, FUJIKAWA SEIZO
    低温生物工学会誌 低温生物工学会 41 (2) 50 - 57 1340-7902 1995/12 [Not refereed][Not invited]
     
    Shoot apices of asparagus (Asparagus officinalis L.) can be successfully cryopreserved (by freezing at a rate of 0.5℃/min in the presence of 8% DMSO and 0.2 M sorbitol) after pretreatments either by precultufe in media containing 0.5 M glucose for 2 days or by cold acclimation at 0℃ for 20 days. In the present study, we examined the effects of pretreatments for subsequent successful cryopreservation of the shoot apices. Freezing tolerance, as revealed by LT_<50> under equilibrium-freezing, was -20℃ in both specimens with pretreatment by 0.5 M glucose and by cold acclimation, while LT_<50> was -7℃ in control specimens. Both pretreatments produced distinct cellular ultrastructural changes as observed with ultra-thin section electron microscopy. Number of plastids rich in starch granules increased in precultured specimens, whereas those poor in the starch granules increased in cold acclimated specimens. Occurrence of freezing injury by equilibrium-freezing, as observed with a freeze-fracture replica technique, was associated with formation of aparticulate domains with accompanying fracture-jump lesions in the plasma membranes, not only in precultured specimens with 0.5 M glucose and in cold acclimated specimens, but also in control specimens.

MISC

Books etc

  • 作物学
    実山 豊 (Contributorライムギ・エンバク)
    文永堂出版 2013/11
  • 園芸学の基礎
    実山 豊 (Contributor植物の成長と水の役割)
    農山漁村文化協会 2012/09
  • Cryopreservation of tropical plant germplasm -current research progress and application-
    Fujikawa, S, Y. Jitsuyama (ContributorUltrastructural aspects of freezing adaptation of cells by vitrification)
    IPGRI 1998

Presentations

Association Memberships

  • The Hokkaido Society for Horticultural Research   THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE   Hokkaido branch, the Crop Science Society of Japan   The Crop Science Society of Japan   JAPANESE SOCIETY FOR CRYOBIOLOGY AND CRYOTECHNOLOGY   

Research Projects

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2021/04 -2024/03 
    Author : 鈴木 卓, 春日 純, 実山 豊, 上野 敬司
     
    1）圃場試験：みつ症果を発生する‘こうとく’および‘Red Gold(RG)’の成木（北大余市果樹園栽植）で、全面マルチおよび主枝に施した針金リング処理がみつ症果発生に及ぼす影響を調べた。みつ症の発生程度は、経時的に採取した果実（５果）の縦および横断面をwin-RHIZOで画像解析する方法により評価した。みつ症程度は両品種とも収穫直前の果実で顕著で、‘RG’の針金リング区は、対照区に比べて有意にみつ組織の面積が拡大した。 ２）維管束組織の微細構造：みつ症果の発生に顕著な品種間差が認められており、果梗部から果実に至る維管束組織の構造的差異が、篩部液の果実内流入を制限している可能性があるため、果梗部を化学固定後パラフィン包埋し、横断切片を顕微鏡観察した。その結果、果梗部は、枝と同様にその中心を木部が大きく占め、篩部組織はその周辺を覆うように発達している様子が確認できた。 ３）MALDI-TOF MS imaging：7月下旬に採取した‘こうとく’の未成熟果を表面殺菌後、無菌条件下で縦および横に切断し、その切断面を0.5Mの[1-13C]sorbitolを添加したMS培地で72時間培養し、MALDI-TOF MS imagingによる観察を行った。リンゴ果肉組織内で外与の[1-13C]sorbitolを基質として合成されたsucrose（通常のsucroseよりもm/zが1または2大きい分子）の果実内分布を観察したところ、[1-13C]を内包するsucrose濃度は果実中心部で低く、果肉の果皮側で高いことがわかった。 ４）Sorbitolおよびsucrose代謝関連酵素遺伝子の解析：果肉組織から採取されたRNAの量および純度が低く、解析が容易ではないことがわかった。果肉細胞は大きく、核酸抽出には不向きな材料であるため、酵素活性に着目して研究を進める方が得策であると判断した。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    Date (from‐to) : 2020/04 -2023/03 
    Author : 志村 華子, 鈴木 卓, 実山 豊, 杉山 慶太
     
    スイカの雌花にユウガオの花粉を受粉すると約50％の確率で単為結実が生じる。ユウガオの花粉はスイカの子房内で単為結実を引き起こす特異的な反応を誘導すると考え、今年度も受粉処理から経時的にスイカ子房を採取し、RNA-seqを用いたトランスクリプトーム解析によって単為結実に関わる遺伝子の探索を行った。ユウガオ花粉を受粉した際に、肥大または非肥大の違いが視覚的に判別可能になるのは受粉96時間以降だが、受粉72時間後のユウガオ受粉区（9個体）の遺伝子発現パターンをみると、4株はスイカ受粉区と同様のパターン、5株は単為結実を誘導しないニガウリ受粉区と同様のパターンを示したことから、前者は肥大し、後者は肥大しないと予想された。肥大すると思われるユウガオ花粉受粉72時間区でのみ発現量が高い遺伝子には、細胞壁修飾酵素を制御するタンパク質をコードする遺伝子DUF642やABAおよびストレス誘導遺伝子HVA22などがみられた。肥大すると予想されるユウガオ花粉受粉72時間区とスイカ受粉区で共通して発現上昇しているものにはGA合成遺伝子が検出された。一方、肥大しないと思われるユウガオ花粉受粉72時間区で発現量が高い遺伝子の多くはニガウリ受粉区でも発現量が高く、ジャスモン酸応答、ブラシノステロイド応答に関わる遺伝子が多く検出された。また、さらに早い時間（受粉後36時間、48時間）では、受粉区による遺伝子発現パターンの中に結実の有無と関連がありそうな傾向は明確には見出されなかった。実際にはまだ肥大は起こっていないが、単為結実となるかどうかを決定する遺伝子発現の違いは受粉72時間後ではもう起こっていると考えられた。受粉後36から48時間はまだ肥大方向へ進むかどうか過渡期の状態ではないかと思われ、72時間までの経時的変化をさらに詳細に調べる必要があると考えられた。
  • 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 : Sugiyama Keita
     
    We studied the phenomenon of parthenocarpy of watermelon induced by pollinating with bottle gourd pollen. Bottle gourd pollen had high contents of IAA and isopentenyl adenine. The change in ABA in watermelon ovary after pollination with bottle gourd pollen were similar to that of pollination of watermelon pollen. In addition, auxin response factor (ARF) and auxin/indole 3-acetic acid (AUX/IAA) were detected by proteomic analysis, and it was considered to be related to parthenocarpy. The gene expression patterns in the ovary of watermelon induced by pollination of watermelon pollen and bottle gourd pollen were similar, it was shown that gene expression changes related to parthenocarpy occurred 48 hours after pollination. In the family Cucurbitaceae, we revealed that there were many combinations of parthenocarpy induced by pollinating using another genus pollen.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
    Date (from‐to) : 2016/04 -2018/03 
    Author : SUZUKI TAKASHI
     
    The authors hypothesized that the water core tissue could be formed by overflowed sorbitol-rich sap into the intercellular space which was translocated via peduncle just before maturing of the fruits according to the previous observations using Cryo-SEM. Pseudo water core tissue was formed artificially in maturing apple fruits by injecting red-dye solution via peduncle using pressure-chamber apparatus. After a treatment with 200 kPa for 24 h the center, vascular bundles in receptacle and inside of epidermis on horizontal section of the fruits were red-stained, but the original water core tissue was not. Thus, water core development would not be related to overflow of sap. Distribution of sorbitol and sucrose in apple fruit flesh was visualized utilizing MALDI-TOF imaging MS. Sorbitol accumulated around center of the fruit, but sucrose content became gradually higher in cortex side. Sorbitol distribution in a water core fruit did not entirely coincide with the water core tissue regions.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
    Date (from‐to) : 2015/04 -2017/03 
    Author : FUKUSHI YUKIHARU
     
    The crude extracts of plant leaves (65 species) were examined in this research revealed that they showed various levels of anti-ice nucleation activity (supercooling activity). In particular, the leaf extracts of Picea glehnii, Brassica juncea (red mustard), Sasa senanensis, Salix bakko, Laurus nobilis, Citrus sudachi, Perilla frutescens, Camellia sinensis, and Taraxacum officinale showed relatively high anti-ice nucleation activity by droplet freezing assays. Anti-ice nucleation effects were clearly shown on leaves by using our new leaf-disc freezing assay system. Application of plant extracts in a tea plantation is in consultation.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2014/04 -2017/03 
    Author : JITSUYAMA Yutaka
     
    Soybean is easy to suffer flooding injuries at both stages of seeding and vegetative growth. To understand the mechanism of the injury, we investigated the wet tolerance of various soybean cultivars focusing on the water permeability of the root or the seed coat. In case of vegetative injury, the tolerant cultivars had abilities of increasing root mass and specific root aquaporins in hypoxia condition, and kept the high root conductivity even under flooding. In case of seed flooding injury, the QTLs from tolerant wild lines could increase the germination rate after flooding, and one of them is same one for ‘seed hardness’. Thus, two different types of soybean flooding injuries might link to the organ water permeability closely.
  • Study of relationship between soybean comprehensive wet endurance and water permability of tissue cells
    Japan Society for the Promotion of Science：Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2014/04 -2017/03 
    Author : JITSUYAMA Yutaka
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2013/04 -2016/03 
    Author : Ishikawa Junko, MURAI Mari, MATSUO Naoki, JITSUYAMA Yutaka
     
    Soybean is generally susceptible to flooding. In Japan, flooding is a serious problem, because soybeans are often cultivated in the fields converted from paddy fields. Understanding mechanism of the flooding susceptibility is important for developing tolerant genotypes. In the present study, we investigated role of aquaporins in inhibition of water uptake under the flooding. Aquaporins play key roles in regulation of water uptake from the roots. We demonstrated that submerging treatment decreased gene expression of nine major root aquaporins. It suggests that the decrease in the aquaporin expression is a contributing factor in inhibition of water uptake from the roots of submerged plants.
  • Japan Society for the Promotion of Science：Grant-in-Aid for Exploratory Research
    Date (from‐to) : 2012/04 -2014/03 
    Author : JITSUYAMA Yutaka
     
    Dried soybean seeds are prone to suffer waterlogging injury just after seeding if they are exposed to excess moisture. After 3 hr of waterlogging treatment, significant differences in seed survival were detected among cultivars. In addition, the passive imbibition during 10 - 30 min of waterlogging, and the capillary imbibition during 0 - 10 min of flooding were caused by significant differences in the imbibition rate among cultivars. Although neither imbibition showed a significant correlation with the survival directly, the ratio between the passive and the capillary imbibition rate was significantly correlated with survival. Factors affecting imbibition included the hydraulic conductivity of the seed coat and seed osmolarity, which were significantly correlated with the passive and the capillary imbibition rate, respectively.
  • Basic study of various crop activities and adaptability to hypoxic circumstance
    Japan Society for the Promotion of Science：Grant-in-Aid for Young Scientists (A)
    Date (from‐to) : 2010/04 -2013/03 
    Author : JITSUYAMA Yutaka
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (A)
    Date (from‐to) : 2010 -2012 
    Author : JITSUYAMA Yutaka
     
    Soybean’s wet injury is important obstacle in the production, however themechanism has not been clear. In this study, ‘low oxygenic condition’ was made artificially as a modelof wet soil with a hydroponic culture, various soybeans whose field-wet endurance were known, werestudied on the response for low oxygen. As results, the relationship between the response and the wetendurance was detected, and concluded that one of the main factor for soybean’s wet injury was lowoxygen. And cultivar-specific response for low oxygen, as like the reduction of leaf area or fine root,and the decline of root water uptake were found out.
  • Survey for weed control method with characteristics peculiar to a cold district
    Japan Society for the Promotion of Science：Grant-in-Aid for Exploratory Research
    Date (from‐to) : 2007/04 -2009/03 
    Author : JITSUYAMA Yutaka
  • 日本学術振興会：科学研究費助成事業 萌芽研究
    Date (from‐to) : 2007 -2008 
    Author : 実山 豊
     
    雑草防除を容易に省力化できれば, 更なる作業体系の拡充等が可能であろう. 適応範囲として北海道のような寒冷地域の積雪下に限定されるが, 寒剤の凝固点降下現象の雑草発芽抑制への利用の可能性について, 2年間のポット・圃場試験を行った. 試験1年目に寒剤の圃場散布を模した調査を行った. 雑草埋土種子の出芽を有意に減少させるに十分な温度低下は高濃度の寒剤(30%w/w)で確認されたが, これは塩傷害をも誘引し, 凝固点降下効果が薄い0.4%w/wの寒剤混和でも塩害様相を呈した. 一方で, 雑草埋土種子の出芽は, 寒剤を混和せずに-20℃以低にまで低下させれば減少し, また, 十分量の雪と寒剤が混和されれば,-20℃近辺まで低温化する凝固点降下も確認された. これらのことから, 寒剤を圃場に直接混和することなく凝固点降下の効果のみを抽出, 土中に伝達させれば, 翌春の雑草数が減少する可能性が考えられた. 試験2年目には, 高濃度寒剤を包含したシートの圃場被覆を模した調査を行った. この手法による雑草埋土種子出芽抑制効果は, 十分量のNaCl, CaCl_2, MgCl_2を用いた際,-20℃〜-80℃程度の低温条件と同等と示された. 次に融雪剤として市販されているMgCl_2を用いて, 圃場(エンバク緑肥圃場として用いられる圃場で, 除草剤処理は一切行っていない)での小規模実験を行った. 寒剤シートで処理すると, 対照区に較べ総雑草数は5%水準で有意に減少し, 雑草種に依っては(エノキグサ)1%水準で寒剤の効果が認められた. ただし, 本圃場の優占種だったシロザ等については効果が薄かった. シート被覆後に播種されたエンバクについても処理の効果は示されなかった. 以上のことから, 降雪前の圃場に寒剤を含む資材(繰り返し使用可能)を土壌被覆することにより, 春〜夏期の出芽雑草数を抑制できる可能性が示唆された. しかしながら資材の選定や抑制効果の安定性・強度に課題は残され,更なる検証が必要であると結論した.
  • New methodlogy for study of crop root activity under multiple soil stress
    Japan Society for the Promotion of Science：Grant-in-Aid for Young Scientists (A)
    Date (from‐to) : 2004/04 -2007/03 
    Author : JITSUYAMA Yutaka
  • 日本学術振興会：科学研究費助成事業 若手研究(A)
    Date (from‐to) : 2004 -2006 
    Author : 実山 豊
     
    作物根に対する複合型土壌環境ストレス(乾燥ストレス,塩ストレス,緊密土壌ストレス)には多くの場合,土壌中の水動態が密接に関連している.本研究は,最終的に作物育成環境での水動態モニターを目指しており,作物根への土壌ストレスの調査基盤として,密閉簡易型の作物育成ポットによる水のトレーサー試験の手技を確立した.以下研究概要を示す. ・D2Oによる水動態のトレースが可能な透明アクリル樹脂製小型ポットを製作し,土壌水分センサーにより土壌体積含水率の土壌水の拡散状況に関する基礎データを得た.これらデータおよび作物根系の深度を勘案し,本試験用機8機(幅:40cm,奥行き10cm,深さ120cm)を製作した. ・実際にD2Oを負荷しトレース実験を開始した.平成16年度申請備品のFTIR(フーリエ変換赤外分光光度計)により,0.05〜10atom%までの濃度においてD2O定量をルーチン化し,土壌から蒸散する水蒸気に含まれるD2Oも,コールドトラップを用いる事で定量化とした.また,土壌中から抽出した溶液中の元素定量に関しても,平成16年度申請備品のXRF(エレメントアナライザ)による定量法を確立した. ・複合土壌ストレスのひとつとして乾燥ストレスを作物に負荷しD2Oトレース試験を行い,「土壌からの根水吸収→植物体を通導→大気への蒸散」という,一連の水分動向における日変動への土壌ストレスの影響を明らかにした. これまで確立した新しい方法論に従い基礎的知見を蓄積し,緊密土壌・塩等の土壌ストレスを複合的に発生させた条件を作物に負荷した上で,引き続き根挙動への影響を精査する.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2003 -2006 
    Author : IWAMA Kazuto, JITSUYAMA Yutaka, WATANABE Nobuyoshi
     
    It is afraid that under future global warming the shortage of water becomes more serious beyond the present and the plant water absorption from the soil becomes the main factor which regulates the productivity of the crop in many areas of the world. To maintain food production corresponding to the population growth of the world, we need to make available for the crops to absorb the unused water existing in deep soil by improving root PA to hard soil layers (root PA). The present research examined the genetic variation and its heredity style about root PA of wheat, and the following results were obtained. 1. A pot with a paraffin-Vaseline mixed layer (PV pot), which was suitable for the measurement of root PA in wheat, was developed. It was verified that a genotypic difference in root PA in fields with hard soil layer agreed well with those evaluated by the test with PV pot. 2. Root PA evaluated with PV pot in modern high yielding cultivars of the durum wheat bred by ICARDA and CIMMYT was inferior to that of Ethiopian land races which grew well in fields with hard soil layers. Moreover, a big variation existed in the root PA tested for the domestic bread wheat genotypes, suggesting that superior genotypes could be used as the heredity resources to improve root PA. 3. Root PA of isogenic lines of durum wheat about dwarf which controls plant length and harvest index was compared. Significant relations between dwarf and root PA weren' t recognized, indicating that the two characters were hereditarily independent. Furthermore, QTL related to root PA was located in the head arm extreme bottom part of the chromosome 6A was defined in the map group of durum wheat.
  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    Date (from‐to) : 2005 -2005 
    Author : 寺内 方克, 岩間 和人, 実山 豊
     
    先導的な研究の紹介を通じて研究の現状と今後の課題を明らかにするとともに、研究交流を通じた今後の国際共同研究の立ち上げを目指して「乾燥地における作物根系改良の現状と課題」と題するセミナーを企画した。海外の研究機関から3名の招聘研究者を迎え、国際農林水産業研究センター(JIRCAS)の協力のもと、2005年12月14日にJIRCAS国際会議室でセミナーを開催した。招聘者と講演内容は次のとおり。(1)Dr.Jill Cairns(国際稲研究所(IRRI)、フィリピン)「陸稲における根系改良の取り組みの現状と課題」、(2)Dr.Pooran M.Gaur(国際半乾燥地熱帯作物研究所(ICRISAT)、インド)「ヒヨコマメにおける根系改良の取り組みへの挑戦と現状」、(3)Dr.Richrd Richards(植物工学研究所、オーストラリア)「コムギにおける根系改良の取り組みの現状と課題」。セミナーには国内外から、約50名の参加があり、講演者の他、海外からはアフガニスタン研究局や国際乾燥地農業研究センター(ICARDA)およびICRISATの研究者が参加した。総合討論の時間には今後の根系育種推進案を説明し、これに対する質疑を通じて研究の方向と課題について整理した。そして、根の調査に関わる様々な困難な問題を再確認し、根系を改良するには単純な遺伝様式の形質が適当であること、環境によって求められる根の特性が異なること等を認めつつ、環境分野、生理分野、育種分野等の研究者が連携することが重要であることを確認した。本セミナーの内容については、その内容をPlant Production Science誌に掲載するための準備を進めている。 この他、根の研究に関する先導的な研究を実施しているワーヘニンゲン大学との研究打ち合わせを行い、共同研究に向けた研究材料の交換等の手続きを開始した。
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2002 -2004 
    Author : HASEGAWA Toshihiro, SAKAI Hidemitsu, OKADA Masumi, JITSUYAMA Yutaka, KOBAYASHI Kazuhiko
     
    Growth enhancement of rice by elevated CO_2 can be mediated by the developmental and morphological traits. Much has been studied for the photosynthetic responses but understandings on the effects of elevated CO_2 on morphogenesis of rice are still limited. We therefore attempted to determine the effects of elevated CO_2 (200μmol/mol above ambient) on development and morphology or rice varieties differing in maturity and plant types. Naturally sun-lit growth chambers and free air CO_2 enrichment (FACE) facilities were used for the experiments. Elevated CO_2 advanced heading dates of medium maturing varieties but did not foster development of two early varieties. A contrasting response of lamina length to elevated CO_2 was also observed among the genotypes ; a significant positive effect was found in early varieties but a negative one in medium varieties. The genotypic difference in CO_2 responses of leaf appearance and lamina length occurred mainly in the upper three to four leaves, which developed after panicle initiation. The results suggest that the genotype x CO_2 interaction on the developmental time can influence leaf number and lamina size which have a direct relevance to the rice productivity. We also tested whether genotypic difference in panicle size influences the growth responses to elevated CO_2 using a mutant with limited spikelet number. A parent and its mutant showed a similar growth enhancement due to elevated CO_2 despite the mutant having only 50-60 % of spikelet number per panicle, suggesting that limited spikelet per se does not limit growth enhancement. In all experiments, genotypic variation in photosynthetic responses to elevated CO_2 was mainly due to the difference in leaf greenness or nitrogen content. The results suggest that genotypic variation in growth responses to elevated CO_2 can mostly ascribed to the traits associated with development and nitrogen nutrition.
  • Study of wheat root penetration ability under compacted soil layer stress
    Japan Society for the Promotion of Science：Grant-in-Aid for Encouragement of Scientists (A)
    Date (from‐to) : 2001/04 -2003/03 
    Author : JITSUYAMA Yutaka
  • 日本学術振興会：科学研究費助成事業 若手研究(B)
    Date (from‐to) : 2001 -2002 
    Author : 実山 豊
     
    緊密土壌ストレス下におけるコムギ根系の発展能力について,(1)緊密土壌ストレス耐性の簡易評価法の確立,(2)緊密土壌ストレス耐性と植物形態との関連性に関する調査,(3)圃場における緊密土壌ストレス耐性の検証,の3項目の検討を行なった.以下にこれらの概要を示す. (1)ワックスディスクを組み入れた特殊ポットにてコムギを栽培することで,緊密土壌ストレス耐性選抜に適した簡易評価を可能とした.国内外の研究機関から収集したコムギ系統計60品種を予備実験に用い,広範な根貫入力変異を示すエチオピア在来種7品種,北米育成多収性品種17品種そして北海道内主要品種10品種を見い出した.最終的には,極めて特徴的な根貫入力を示す6品種を選抜できた. (2)緊密土壌ストレス耐性と正相関する植物形態として,根量(種子根・冠根・側根)・草丈・分げつ数が認められた.これらは,土壌深部への根系形成に密接に関連する量的形質と考えられる.また部の根貫入力品種には,個根の貫入能力が高いことで根全体の貫入能力を高めている品種とみられるものもあり,今後は,個根の微細形態についての検討も必要と考える. (3)圃場内にベントナイトを基本とした緊密土壌層を設けた上でコムギを栽培し,塹壕法により根発展程度を経時的に調査したところ,上記ポット試験で認められた現象は圃場においても確認され,これらのストレス耐性が環境に対し安定した遺伝形質であることを明らかにした. 以上の知見は,コムギ根の貫入力特性における遺伝的変異および発現機構を解明する端緒となり,緊密土壌耐性に優れたコムギを作出する上で重要と考える.
  • 日本学術振興会：科学研究費助成事業 特別研究員奨励費
    Date (from‐to) : 1999 -1999 
    Author : 実山 豊

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