夏谷籽粒蛋白质积累和旗叶蛋白质周转的关系

RELATIONSHIP BETWEEN ACCUMULATION OF SEED PROTEINS AND PROTEIN TURNOVER OF FLAG LEAVES IN SETARIA ITALICD BEAUR

谷子灌浆期旗叶蛋白水解酶活性、籽粒和旗叶游离氨基酸含量均呈双峰曲线变化。第一峰在花后１３天；第二峰分别在２５、２８天。籽粒和旗叶游离氨基酸峰稍滞后，且后者不明显。籽粒总蛋白积累和干重增加均为Ｓ型变化，与旗叶总蛋白和可溶性蛋白变化趋势相反。花后２２─２５天上述物质和酶活变化均出现─转折。转折点之前，蛋白质合成和周转活跃；之后，由叶片蛋白酶活性升高引起的旗叶氮素撤离对籽粒蛋白质积累仍有一定贡献（约１０％）。

During the grain development of Setaria italicd Beaur the increase of proteolytic activity in flag leaves and content of free amino acid in flag leaves or grain followed a bimodal with the first peak (maximum) at 13th day post flowering and the last at 25-28th day post flowering. The time course study showed that protein content and dry weight of grain which increased follwing a typical S curve, was in negative related to the total protein and soluble protein contents in flag leaves. All the changes show a turn-point which seemed to 22-25th day post flowering. Before the turn-point, the flag leaves and grains showed protein synthesis and turnover activity and the second increase of proteolytic activity, accompanying by the withdraw of nitrogen from flag leaves was also cause of accumulation of grain protein and dry weight of grain.