水分胁迫与植物氮代谢的关系 水分胁迫时氮素对小麦叶片氮代谢的影响

本研究结果表明,提高氮素营养水平可减缓缺水植物的氮代谢紊乱,增强其抗旱性。即在水分胁迫时,氮素营养水平较高的小麦叶片具有较高的硝酸还原酶活性和较低的蛋白酶、肽酶及核糖核酸酶活性,从而使蛋白质和RNA保持较高的水平,且游离氨基酸大量积累的土壤水分临界值也有所降低。并进一步证明,氮素对氮代谢的良好影响是因为改善了植物体内的水分状况。此外,对氮素增强植物抗旱性的机理和旱区增施氮肥的意义也进行了讨论。

RELATIONSHIP BETWEEN WATER STRESS AND PLANT NITROGEN METABOLISM II. EFFECTS OF FERTILIZER NITROGEN ON NITROGEN METABOLISM IN WATER STRESSED WHEAT LEAVES

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.