| Project/Area Number |
03304004
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物生理学
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| Research Institution | Saitama University |
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Principal Investigator |
KANAI Ryuzi Saitama Univ.,Fac.Science,Professor, 理学部, 教授 (30008817)
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| Co-Investigator(Kenkyū-buntansha) |
SUGIYAMA Tatsuo Nagoya Univ.,Fac.Agric.,Professor, 農学部, 教授 (50023453)
SAWADA Shin-ichi Hirosaki Univ.,Fac.Sci.,Professor, 理学部, 教授 (70106839)
USUDA Hideaki Teikyo Univ.,Fac.Med.,Assoc.Professor, 医学部, 助教授 (90112755)
ISHIHARA Kuni Tokyo Univ.Agric.Technol.,Fac.Agric.,Professor, 農学部, 教授 (70014925)
ASADA Kozi Kyoto Univ.,Inst.Food.Sci.,Professor, 食料科学研究所, 教授 (50027182)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Photosynthesis / Carbon dioxide / C_4 plants / Environmental stress / Nitrogen deficiency / Phosphorus deficiency / PEP carboxylase / RuBP carboxylase |
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| Research Abstract |
Plant responses to suboptimal environment and limiting nutrition were studied with an emphasis on photosynthetic carbon and nitrogen metabolism.
1)High ambient O_2(60%) increased glutathione reductase in both C_3 and C_4 plants. The target enzyme of high O_2 stress in chloroplasts is being investigated.
2)High CO_2(1%)decreased PEP carboxylase (PEPC) in C_4 plants but glycolate oxidase only in C_3 plants. A unicelluear green alga, Chlamydomonas,when grown in low CO_2,developed pyrenoid which contained a larger amount of RUBP carboxylase (RubisCO) protein. Fine regulation of RubisCO activity was investigated with a proposal of putative binding site(s) of substrate or the analogues and pi.
3)Decrease in photosynthesis of C_4 plants during the deprivation of phosphorus source was due to the decrease in the activities of pyruvate,Pi dikinase,PEPC and RubisCO.
4)Nitrogen application to N-deficient C_4 plants specifically induced PEPC and carbonic anhydrase(CA). The signalling mechanism seemingly involved cellular glutamate level and a plant hormone cytokinin. Although C_3 plants showed large differences in the control of CA and RubisCO levels in response to various degrees of N stress,the ratio of photosynthetic electron transport and carbon assimilation systems was kept constant among the C_3 species.
5)Low temperature-induced decrease of photosynthesis in cucumber was due to the inactivation of ferredoxin-thioredoxin reductase which activates FuBPase in PCR cycle.
6)The effects of senescence(or aging)on photosynthesis and enzyme activities were investigated and discriminated from those of shading with a vine plant grown horizontally.
7)Water stressed rice plants showed low photosynthetic rate due to decreased stomatal conductace,and those grown in high humidity became more sensitive to water stress.
8)Source-sink control of photosynthesis and RubisCO activity was investigated in a model leaf-root system and also in field grown soy-bean plants.
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