氮钾营养对春玉米叶片衰老过程中激素变化与活性氧代谢的影响

采用田间试验、砂培试验和植株分析等方法,从激素水平和活性氧代谢方面探讨氮钾互作对春玉米叶片衰老的影响及其机制。结果表明,氮钾配比适宜可提高生育后期穗叶叶绿素含量,增加IAA、ZR 及GA3 含量,降低ABA 含量,提高IAA/ABA、ZR/ABA 及GA3/ABA 之比;过氧化物酶活性降低,膜质过氧化产物丙二醛含量减少,超氧物歧化酶活性增加,从而延缓衰老。而氮钾比例失调则导致内源激素平衡受到破坏,氧自由基清除能力降低,由此引起早衰,子粒产量降低。

EFFECT OF N AND K NUTRITION ON CHANGES OF ENDOGENOUS HORMONE AND METABOLISM OF ACTIVE OXYGEN DURING LEAF SENESCENCE IN SPRING MAIZE

Field trial, sand culture and plant analysis were used to study the effect of N and K interaction on leaf senescence and its mechanism emphasized on aspects of endogenous hormones and metabolism of active oxygen in spring maize. The results indicated that rational ratio of N to K could increase contents of chlorophyll, IAA, ZR and GA3, and lower content of ABA. With rational ratio of N to K, the ratio of IAA/ABA, ZR/ABA and GA3/ABA increased, the activity of POD and the content of MDA which is the product of lipid peroxidation decreased, while the activity of SOD enhanced, which delayed leaf senescence. However, the balance of endogenous hormones was broken, and the ability to scavenge free radicals declined, resulting in early senescence and lowered grain yield with irrational ratio of N to K.