1994 Fiscal Year Final Research Report Summary
Change in the pathway of carbon-fixation from C_3 to C_4 by some amphibious Cyperacean plants
| Project/Area Number |
05640724
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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 |
植物生理
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| Research Institution | Saitama University |
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Principal Investigator |
KANAI Ryuzi Saitama University, Fac. Science, Professor, 理学部, 教授 (30008817)
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| Co-Investigator(Kenkyū-buntansha) |
KORE-EDA Shin Saitama University, Fac.Science, Res.Assoc., 理学部, 助手 (20234924)
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| Project Period (FY) |
1993 – 1994
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| Keywords | C_4 plant / C_3-C_4 intermediate / C_4 photosynthesis / amphibious plant / Cyperaceae / Eleocharis / photorespiration / carbonic anhydrase |
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| Research Abstract |
An Cyperacean plant, Eleocharis vivipara, was reported by Ueno and coworkers (1988) to have C_4 and C_3 mode of photosynthetic carbon pathway in its terrestrial (T) and submersed (S) form of growth, respectively. For further characterization of this and other ambphibious Eleocharis species, we developed in vitro culture system to remove contaminating algae attached to S from of plants in nature and to control the environmental conditions precisely.
Transferring E.vivipara from T to S from, enzyme activities of C_4 pathway, PEP carboxylase and NAD-malic enzyme, decreased remarkably but those of Calvin cycle, RuBP carboxylase and NADP-GA3P dehydrogenase increased in some extent. The former activities also decreased when T form was grown in the air containing 1% CO_2. In E.retroflexa, however, enzymes of C_4 pathway kept their high activity in both T and S froms. Enzyme activities of photorespiratory glycolate pathway, such as glycolate oxidase, catalase, serine hydroxymethyltransferase and hydroxypyruvate reductase, were very low in T form of both Eleocharis species, and no increase was obseved by transferring to S from. Thus, S form of E.vivipara seems to be a C_3 plant having low photorespiratory activity, which is similar to some of submersed macrophyte (SAM) species ; while E.retroflexa retains capacity of C_4 pathway even in its S form. Carbonic anhydrase activity did not change much by transfer from T to S from in both species.
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