氮素营养对小麦根冠协调生长的调控

在植物生长箱通过溶液培养方式，对不同氮素条件下不同抗旱性的小麦品种西农1043和小偃6号的幼苗根苗生长特性进行了研究，结果表明在不同氮素浓度下，氮肥用量的提高对地上部干重和叶片气体交换参数表现为增效效应，当用量增至一定程度时，地上部干重和叶片气体交换参数均呈下降趋势，只是各自的适宜用量存在差异。培养介质氮素浓度低时，有利于小麦根系干重累积，培养介质氮素浓度高时，不利于根系干重累积。西农1043和小偃6号根长分布基本相似，水分利用效率随着根冠比的增大而降低。小麦根冠比的增加并不利于叶片水分利用效率的提高，而叶片光合作用最优的根冠比为0．5左右。

The effect of nitrogen nutrition on coordinate growth of root and shoot of winter wheat

The effect of nitrogen nutrition on coordinete growth of root and shoot of different wheat gene-types were studied. The result showed that at different nitrogen nutrition Ievels,the shoot dry weight and leaf gas exchange parameters were increased with nitrogen supplies, but they were both decreased in high nitrogen treatments. It was helpful to the accumulation of root dry weight in low nitrogen nutrition concen-tration, which means that the accumulation of root dry weight was negative correlated with nitrogen con-centration. The distribution of root length of Xinong No. 1043 in different depths was similar to Xiaoyan No. 6:the root length of 5-10 cm and 10-15 cm were longer than that of 0-5 cm. The water use efficien-cy was decreased with the increase of root/shoot ,this showed that high R/S didn't mean the high water use efficiency.