1995 Fiscal Year Final Research Report Summary
Activation Mechanisms in Rice Photosynthesis
| Project/Area Number |
06660018
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
作物学
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| Research Institution | Kobe University |
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Principal Investigator |
UCHIDA Naotsugu KOBE UNIV., FAC.AGRICULTURE,ASSOCIATE PROFESSOR, 農学部, 助教授 (70151884)
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| Co-Investigator(Kenkyū-buntansha) |
AZUMA Tetsushi KOBE UNIV., GRAD.SCHOOL SCI.& TECH., ASSISTANT PROFESSOR, 大学院・自然科学研究科, 助手 (30231913)
YASUDA Takeshi KOBE UNIV., FAC.AGRICULTURE,PROFESSOR, 農学部, 教授 (20026553)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Oryza sativa / Photosynthesis / Rice / Rubisco / Rubisco activase |
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| Research Abstract |
We investigated the activation mechanisms of rice photosynthesis in relation to Rubisco activase.
(1) We purified Rubisco activase from rice leaves, and showed the existence of this enzyme in rice leaves.
(2) The amounts of Rubisco activase and Rubisco, and several photosynthetic characteristics in rice plants grown under different nitrogen concentrations and light intensities were investigated. The amounts of Rubisco activase increased linearly with increasing nitrogen supply regardless of the growing light conditions, whereas that of Rubisco increased slightly under the shade condition. The amount of Rubisco activase was almost linearly correlated to the maximum rate of photosynthetic oxygen evolution and the carboxylation efficiency, an indicator of in vivo Rubisco activity.
(3) Photosynthetic activity (OER) and the amounts of leaf constituents were investigated in a rice leaf in relation to its aging. The changing pattern of Rubisco activase content was most remarkable among the leaf constituents examined. The OER depended linearly on the Rubisco content below the value of 3 g m^<-2>, but tended to saturate above this value. On the contrary, the amount of Rubisco activase and the OER were linearly correlated during the life span of the leaf. Therefore, the in vivo Rubisco activity can be restricted by Rubisco activase content.
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