氮素营养水平对小麦旗叶衰老过程中蛋白质和核酸代谢的影响

在大田高产条件下 ,研究了氮素营养水平对小麦旗叶衰老过程中蛋白质和核酸代谢变化的影响 ,并探讨了蛋白质和核酸代谢的关系。结果表明 ,小麦旗叶衰老过程中可溶性蛋白质含量、DNA和RNA含量逐渐下降 ,而蛋白酶和核酸酶活性逐渐升高。早衰型小麦品种旗叶可溶性蛋白质含量、DNA和RNA含量下降快 ,蛋白酶和核酸酶活性上升快 ;氮素营养充足可以提高旗叶可溶性蛋白质和核酸含量 ,降低蛋白酶和核酸酶活性 ,从而延缓小麦旗叶的衰老。蛋白酶活性的提高 ,加剧了蛋白质的降解 ,以及DNA、RNA含量的减少 ,限制了蛋白质的合成 ,是导致旗叶可溶性蛋白质含量下降的主要原因。DNA和RNA含量的减少与DNase和RNase的活性升高 ,DNA和RNA分解加剧密切相关。

Effect of nitrogen nutrition on protein and nucleic acid metabolism during senescence of flag leaf

The effect of nitrogen nutrition on protein and nucleic acid metabolism and discussed the relationship between protein metabolism and nucleic acid metabolism were studied. The results indicated that the contents of soluble protein, DNA and RNA in flag leaf gradually reduced, but the activities of protease and nuclease gradually raised during senescence. Soluble protein, DNA, and RNA contents in flag leaf of cultivar senescence at early stage rapidly reduced and the activities of protease and nuclease rapidly raised. Sufficient nitrogen nutrition could improve the contents of soluble protein and nucleic acid in flag leaf and reduce the activities of protease and nuclease, and delay the senescence of plant. The improvement of protease activity improved to decompose the protein, decreased the contents of DNA and RNA, which led to the reduction of soluble protein in flag leaf. The reduction of DNA and RNA contents correlated to the improvement of DNase and RNase activities, and decomposition of DNA and RNA.