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[目的]探索夏玉米氮肥后移效应及增产机理,以期为合理施用氮肥提供理论依据。[方法]在夏玉米超高产区采用田间试验研究了氮肥后移对夏玉米氮代谢关键酶、产量及氮肥利用效率的影响。[结果]氮肥后移使吐丝后28d夏玉米穗位叶硝酸还原酶(NR)、蔗糖磷酸合成酶(SPS)和谷氨酰胺合成酶(GS)活性分别提高了11.99%～34.87%、8.25%～10.64%和10.00%～16.81%;显著增加了叶片可溶性糖含量,使成熟期植株氮素积累量增加5.00%～9.74%。“30%苗肥+30%大喇叭口肥+40%吐丝肥”氮肥后移模式较习惯施氮增产5.05%,氮肥利用率和农学效率分别提高了6.87%和1.75kg/kg。[结论]超高产夏玉米区氮肥后移使灌浆期夏玉米叶片NR、GS和SPS活性维持较高水平,促进了氮素吸收利用,较好地协调了夏玉米生育后期碳氮代谢,促进籽粒灌浆而实现增产。
[Objective] The study aimed to explore the effect of nitrogen application on summer maize and the mechanism of increasing yield, in order to provide a theoretical basis for the rational application of nitrogen fertilizer. [Method] The field experiment was conducted to study the effects of postponing nitrogen application on the key enzymes of nitrogen metabolism, yield and nitrogen use efficiency in summer maize. [Result] The activities of nitrate reductase (NR), sucrose phosphate synthase (SPS) and glutamine synthetase (GS) of ear maize were increased by 11.99% -34.87%, 8.25 % ~ 10.64% and 10.00% ~ 16.81%. The content of soluble sugar in leaves increased significantly, and the nitrogen accumulation in mature plants increased 5.00% ~ 9.74%. 30% of seedling fertilizer + 30% of big bellmouth fertilizer + 40% of silking fertilizer "The nitrogen-translocation mode was accustomed to increasing nitrogen yield by 5.05%, nitrogen use efficiency and agronomic efficiency by 6.87% and 1.75kg / kg, respectively. [Conclusion] The post-nitrogen application of N in high yield summer maize area kept high levels of NR, GS and SPS activities in maize leaves during grain filling stage, promoted the uptake and utilization of nitrogen and coordinated the metabolism of carbon and nitrogen at the later growth stage of summer maize, Grouting and increase production.