Effect of nitrogen fertilizer application at stages in different proportions on protective enzymes activity in leaves of super high yield maize | 氮肥不同比例分期施用对超高产玉米叶片保护酶活性的影响

Chinese. 研究不同氮肥施用方式对超高产玉米叶片保护酶活性变化规律的影响，为玉米超高产模式研究提供理论依据。以超高产玉米品种先玉335为试验材料，在氮肥总量一定的条件下，按分配比例不同设6个处理：N1.底肥100%；N2.底肥80%，拔节期追施20%；N3.底肥80%，拔节期追施10%，吐丝期追施10%；N4.底肥60%，拔节期追施40%；N5.底肥60%，拔节期追施30%，吐丝期追施10%；N6.底肥60%，拔节期和吐丝期均追施20%，研究氮肥不同比例分期施用对玉米产量、叶片保护酶（超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT））活性及丙二醛(MDA)、叶绿素（Chl）和可溶性蛋白含量的影响。N6处理玉米产量最高，N2处理玉米产量最低，N6处理比N4、N1、N2处理分别增产7.3%，10.2%，11.1%。在灌浆期以前，各处理叶片叶绿素及可溶性蛋白含量差异不显著；灌浆期以后，N6、N5处理叶片叶绿素及可溶性蛋白含量显著高于N4、N1、N2处理。在吐丝期以前，各处理叶片保护酶SOD、POD、CAT活性及MDA含量差异不显著，吐丝期以后N6、N5处理的叶片保护酶SOD、POD、CAT活性显著高于N4、N1、N2处理，而MDA含量则显著低于N4、N1、N2处理。氮肥不同比例分期追施使玉米叶片生育后期保护酶活性增强，延缓了玉米叶片的衰老速度，提高了产量。氮肥最佳施用模式为60%作底肥，拔节期和吐丝期均追施20%，玉米产量最高可达14 852.2 kg/hm2。

English. The effect of nitrogen fertilizer applied in different ways on the change regularity of protective enzymes activity in leaves of super high yield maize was studied to provide a scientific theory for the super-high-yield production model. Six treatments were designed in different distribution proportions under the condition of a certain total nitrogen fertilizer using the super high yield maize hybrid Xianyu-335 as the experimental material: N1. Base fertilizer 100%; N2. Base fertilizer 80%, topdressed in jointing stage 20%; N3. Base fertilizer 80%, topdressed in jointing stage 10%, topdressed in anthesis stage 10%; N4. Base fertilizer 60%, topdressed in jointing stage 40%; N5. Base fertilizer 60%,topdressed in jointing stage 30%, topdressed in anthesis stage 10%; N6. Base fertilizer 60%, topdressed in both jointing stage and anthesis stage with 20%. The effects of nitrogen fertilizer application at stages in different proportions on the outcome of maize, the protective enzyme activity (speroxide dismutase (SOD), proxidase (POD), ctalase (CAT)), the content of malondialdehyde (MDA), the content of chlorophyll (Chl) and soluble protein in leaves were studied. The results showed that the yield of N6 treatment was the highest, the yield of N2 treatment was the lowest, and N6 treatment increased production by 7.3%, 10.2% and 11.1% than N4, N1 and N2 treatmemt respectively. The difference of Chl content and soluble protein in leaves of all different treatments were not significant before filling stage. After that, the content of Chl and soluble protein of N6 and N5 in leaves were significantly higher than that of N4, N1 and N2. The protective enzyme activity and MDA content of each treatment were not significant before anthesis stage, but protective enzyme activities of N6 and N5 were significantly higher than that of N4, N1 and N2 after filling stage,and the MDA content was significantly lower than that of N4, N1 and N2 treatment. The study showed that nitrogen fertilizer application at stages in different proportions can reinforce protective enzyme activity and slow down the aging of leaves in late growth stage, thereby enhancing the yield. The best nitrogen application model is the base fertilizer applied by 60%, both the jointing stage and anthesis stage should be topdressed by 20%. The highest yield of maize can be up to 14 852.2 kg/hm2.