The Dynamic Changes Of Key Enzymes Involved In Starch Synthesis And Their Relationship To Starch Accumulation In The Kernel Of Maize Inbreds

With the development of the economy, the purpose of maize has changed enormously from the food supplies and feedingstuff into raw material of industry and medicine.The demand of maize starch must be increasing dramatically for the need of economy development, population increase and resourse comsuming. To study the mechanism of starch biosynthesis deeply makes more contributions to selecting high yield and high quality maize varity. 2 high starch content and 2 low starch content zea mays inbreds have been selected as materials, and the accumulation of amylose/amylopectin and protein, the activity changes of key enzymes involved in starch synthesis in the kernel and the relationship to the accumulation speed of amylase and amylopectin during grain filling period are evaluated in this article. The main results shows as followed:1. The changing of the accumulation content of starch components appeared like a "S" shape; In high and low starch content inbreds, the difference between the amylose content was distinct, however, the difference of amylopectin content was not. Differences in amylose content among inbreds appeared at the middle to later stage of grain filling but at the beginning stage of grain filling, the finally amylose content of grain depends on the initiating time and the beginning rate of amylose's accumulating. The differences in amylopectin content appeared at the beginning stage of grain filling, furthermore, the higher beginning accumulating rate was, the more amylopectin content, which has no necessary relationship to the rate of accumulation; the accumulation of starch also depends on the rate of accumulation, that has little relationship to the maximal accumulating rate and the time when the peak-value appeared.2. The activities of ADPGPPase, SSS and GBSS of different inbreds had a trend of single-peak curve during the grain filling period and their peak value all appeared on 20~30DAP.The activities of SBE of high starch content inbreds had a trend of single-peak curve and the peak values appeared on 20DAP, while low starch content inbreds shows a double-peak curve, the peak value of zj05's appeared on 20DAP and 30DAP and zj10's appeared on 15DAP and 30DAP.