Poster: Enzymology
Abs #
252: Effect of sucrose concentration on the activities of enzymes related to starch synthesis in detached ear culture
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Presenter: |
Sasaki, Haruto , asa3ki@mail.ecc.u-tokyo.ac.jp |
Authors | Sasaki, Haruto (A) Edo, Ei (A) Uehara, Naoko (A) Ishimaru, Tsutomu (A) Suganuma, Shihoko (A) Ueda, Daisuke (A) Ohsugi, Ryu (A) | | Affiliations: |
(A): Graduate School of Agriculture and Life Science, University of Tokyo
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Grain filling of the rice plant (Oryza sativa L.) is affected not only by the supply of the carbohydrate from source organs but also by sink activity that includes the activities of enzymes in grain, but it is difficult to judge the interaction between source ability and sink activity.
In order to examine the effect of translocated carbohydrate on sink activity, ears were cut at 7 days after flowering and then, they were successfully grown in liquid culture solution containing sucrose, glutamine and vitamins. Grain weights at 12 and 16 days after detached ear culture increased with elevation of sucrose concentration in the liquid culture solution, and higher values of grain weights (22mgDW grain-1) were observed at 50-70 g sucrose l-1. However, grain weight increased little above 80 g sucrose l-1 and it seemed to be due a high water potential.
The effect of sucrose concentration on activities of enzymes related to starch synthesis in grain was analyzed. Though the activities of ADP glucose pyrophosphorylase, soluble starch synthase and sucrose synthase in grains grown without sucrose were rapidly depressed at two days after detached ear culture, these activities in the grains grown with 50-70 g sucrose l-1 was similar to those in non-cutting ear. Thereafter, these activities decreased slowly with the increased in the sucrose concentration in the liquid culture solution, and especially, the grains grown at 50-70 g sucrose l-1 maintained high activity of sucrose synthase. These results suggested that the activities of ADP glucose pyrophosphorylase, soluble starch synthase and sucrose synthase, were affected by the amount of sucrose supplied.
