| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1994: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1993: ¥1,700,000 (Direct Cost: ¥1,700,000)
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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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