Study on Grain Milking Characteristics and Sucrose Metabolism Enzyme Activity of Northern Japonica Rice

During the grain milking period, Liaojing 9 and the hybrid variety 9158 were used to study and analyze the rate of grain milking, changes of sucrose and starch content of superior and inferior grains, and sucrose synthase activity and invertase activity . The results showed that the superior grains of rice, which quickly enter the active grain-milking stage, had higher initial growth power in each entry than that of the inferior grains. The superior grains also performed higher activities of sucrose synthase and invertase, and higher sugar content than those of the inferior grains. So it was helpful to promote the transportation of dry matter into the strong grains, resulting in the increased milked grains during the grain milking period. The result also showed the activity of sucrose synthase was higher than that of invertase during sucrose metabolism. Sucrose synthase mainly controlled imputing sugar content from source to sink.