The research on the accumulation of grain starch and change of related enzymes activity in rice with different amylose contents

Four rice varieties with different amylose contents were used to study the pattern of grain starch's accumulation and the activity of related enzymes,and the correlation between the pattern and activity was analyzed.The results showed that accumulation rate of amylase and amylopectin,granule bound starch synthase( GBSS) and soluble starch synthase( SSS) changed in the pattern of a single peak curve during grain filling. The growth of amylose content reached to the maximum in 5—15 days after flowering in all rice varieties,and was highest in Feiyou188,lowest in Chengnuo88. The content of amylopectin increased significantly in 5—20 days after flowering( P0. 01) and was highest in B6you4761. The accumulation courses of both amylopectin and amylose were well fitted to the logistic equation. The simulation of accumulation process discover that the maximum accumulation rate appears with higher maximum accumulation amount of amylose; and the accumulation amount of amylopectin is positive correlated with the an earlier appearance of the maximum accumulation rate and a longer active accumulation days.The accumulation amount and rate of amylose,GBSS activity in Feiyou88 with a high AC content were significantly higher than other varieties. The amylopectin accumulation and accumulation rate in Chengnuo 88 reached to the highest within 15 days after anthesis,but its SSS activity in grain was low. The 1000-grain weight of Feiyou88 was higher than that of other varieties during end filling stage. Correlation analysis indicates that there is a positive correlation between accumulation rate of grain starch and the activity of GBSS and SSS in all rice varieties,which illustrates that activity of GBSS and SSS affect the accumulation of grain starch.