Effect of Different Fertilizer Supply of Maize on Protective Enzyme Activities and Lipid Peroxidation of Leaves in Latter Stage

From the viewpoint of high-yield application of fertilizers,under different fertilizer supply,studies were made about protective enzyme activites and lipid peroxidation of leaves in later stage of maize.Results indicated that at filling stage,milky stage and dough stage,changing of enzymes with growing stage were the same trend,the activities of superoxide dismutase(SOD) reduced sharply then increased slightly;catalase(CAT) declined all the time;peroxedase(POD) increased earlier then reduced,malondialdehyde(MDA) increased straight.Effects of different fertilizer supply on protective enzyme activities and MDA content were different.Propriety N,P,K fertilizer application(N 240 kg/ha,P2O5 150-225 kg/ha and K2O 240 kg/ha) can defer decrepitude effectively of leaves at latter growing stage.Apply excessive or lacking N,P and K fertilizer can sharpen lipid peroxidation degree and became decrepitude earlier.