库大小对水稻不同叶位叶片氮代谢的影响

Effects of Sink Size on Nitrogen Metabolism in Different Position Leaves of Rice

采用去穗与疏花方式调节库大小 ,研究了对水稻不同叶位叶片氮代谢的影响。去穗或疏花后 ,已完成发育的源叶片 ,尤其是顶 4叶 ,蛋白质合成重新旺盛 ,蛋白氮含量提高 ,出现了类似于生长库的氮代谢特征。水稻叶片的酸性转化酶活力可反映其蛋白质合成能力 ,据此可判断叶片是属于氮素供应源还是氮素接受库。研究证实下位叶的氮代谢对植株缺氮的反应比上位叶敏感 ,顶 4叶酸性转化酶活力低是植株从土壤中吸收的氮素不能满足生长库氮需求的一种指示。

The effects of sink size regulation on nitrogen metabolism of different position leaves in rice were studied by removing panicles or spikelets. With panicles or spikelets removed,protein synthesis in full-grown leaves was renewed vigorously,resulting in increased protein nitrogen content,especially in the fourth leaf from the top. The phenomenon was similar to the nitrogen metabolism of growth sink. Capacity of protein synthesis in leaves could be reflected by the activities of acid invertase,which could determine whether the leaf belongs to source or sink of N. The results also showed that the lower position leaves were more sensitive to plant nitrogen deficiency than the upper one,and thus the activities of acid invertase in the fourth leaf from the top was a good indication that the nitrogen absorbed from soil could not meet the nitrogen demand of sink.