RELATIONSHIP BETWEEN WATER STRESS AND PLANT NITROGEN METABOLISM II. EFFECTS OF FERTILIZER NITROGEN ON NITROGEN METABOLISM IN WATER STRESSED WHEAT LEAVES
Zhang Dianzhong Wang Peihong(Department of Basic Course)
Studies were conducted with wheat (Triticum aestivum L. ) cv. Wei mai 4 to determine the effects of N levels on nitrogen metabolism in water stressed leaves. Results showed that higher N level partially relaxed the disorder of nitrogen metabolism caused by water stress, so increased the plant resistance to drought. In water stress conditions, leaves of wheat plant grown in higher N level compared with that grown in lower N level had higher nitrate reductase activity and lower hydrolase (proteinase, peptidase and RNase) activities and remained higher protein and RNA levels. Higher N level also lowered the critical value of soil moisture at which wheat leaf accumulate amino acids greatly, the experiments further confirmed that N application is beneficial to leaf nitrogen metabolism due to a improved water situation within the wheat plants. Mechanisms of increasing plant resistance to drought by N application and its importance to dryland agriculture was discussed.