氮密互作对夏玉米物质生产及氮素利用的影响

以夏玉米杂交种郑单958为材料,对不同种植密度和不同施氮水平下夏玉米的物质生产和氮素利用状况进行了研究。结果表明,在中(67 500株/hm2)、高(82 500株/hm2)密度下,氮肥对玉米单株物质生产能力的调控作用更为明显,并主要是通过影响穗粒数来实现的。适量施氮,可促进顶部子粒发育,减少败育,使秃尖缩短、瘪粒数减少,增加穗粒数,增加产量;促进植物体吸收的氮素高效地向籽粒中分配,提高氮肥的利用效率;使玉米叶片维持较高的光合性能,为籽粒形成提供充足的光合碳量,并促进营养体碳氮向子粒运转。

Effect of Nitrogen Supply on Dry Matter Productivity and Kernel Set in Summer Maize (Zea mays L. ) with Different Plant Populations

Effect of nitrogen(N) supply on dry matter productivity and nitrogen use efficiency in summer maize(Zea mays L.) hybrid Zhengdan 958 with different plant population was studied.The results showed that the effect of N on grain yield of individual plants,mainly acted through the regulation of kernel number,was more evident in 67 500 plants/ha and 82 500 plants/ha.Appropriate N could improve the development of apical kernel,and increase kernel number and yield by reducing aborted kernels.N use efficiency could be increased by distributed more N absorbed by plant to kernel.Appropriate N could not only keep leaves with higher photosynthesis ability and provide more assimilate to grain,but also accelerate C-N mobilization from vegetative organs to grain.