Varietal Differences in Amylose Accumulation and Activities of Major Enzymes Associated with Starch Synthesis during Grain Filling in Rice

Based on comparison of amylose content(AC) at different stages of grain filling period among 3 types of rice including indica, japonica and waxy, the relationship between AC and the activities of 6 key enzymes associated with starch synthesis was analyzed in this paper. The results indicated that similar trends of AC could be seen for Zhe733( indica rice) and Zhenong 104( japonica rice), in which lower AC value was at the early stage of grain filling and higher AC value was at the later stage of grain filling, but it was not clear for Zaoxiannuo( waxy rice). Differences in AC among varieties could be found at the beginning stage of grain filling. Moreover, the activity of the granule bound starch synthase (GBSS) was positively correlated to the ratio of AC to total starch content, but the relationship between AC and other enzymes associated with starch synthesis was not found, including sucrose synthase(SS), ADP glucose pyrophosphorylase(AGPP), soluble starch synthase(SSS), starch branching enzyme(SBE), starch phosphorylase and starch debranching enzyme(DBE).