氮素对超高产小麦生育后期光合特性及产量的影响

Effects of nitrogen supply on photosynthetic characteristics at later developing stages and yield in superhigh-yield winter wheat

本试验在大田条件下研究了施氮量对超高产小麦生育后期光合特性的影响。利用LI-6400便携式光合测定仪,采用开放式气路测定了超高产麦田旗叶的净光合速率、胞间CO2浓度、气孔导度等相关指标。结果表明,氮素对超高产小麦生育后期的光合特性有较大的调节作用,随着施氮量增加,小麦的净光合速率增强,但过高的施氮量(N 375 kg/hm2)导致灌浆后期叶片衰老快,净光合速率下降迅速,叶面积指数降低,千粒重下降明显,最终导致产量的减少。在本试验条件下,超高产麦田的适宜施氮量为N 300 kg/hm2。

The effects of nitrogen supply on photosynthetic characteristics at late developing stage in superhigh-yield winter wheat were studied under field conditions.The net photosynthesis rate（Pn）,intercellular CO2 concentration（Ci） and stomatal conductance（Gs） in superhigh-yield winter wheat were measured using Li-6400 portable photosynthesis system with an open flow gas exchange system.The results showed that nitrogen supply improved the photosynthetic characteristics at late developing stages of superhigh-yield winter wheat.The net photosynthesis rate was enhanced with the increasing of nitrogen supply.However,surplus nitrogen supply（N 375 kg/ha） accelerated the leaf senescence.The highest grain yield was observed in the treatment with N 300 kg/ha applied.