黄淮麦区种植密度对晚播冬小麦花后氮素代谢和利用率的影响

Effects of plant density on nitrogen metabolism and nitrogen use efficiency of late sown winter wheat in Yellow and Huai Valley in China

【目的】研究种植密度对晚播冬小麦氮素同化、分配及其利用效率的影响,为黄河流域晚播冬小麦的高产和氮肥高效利用提供参考依据。【方法】以"新麦18"为材料,研究了低(150万株/hm2)、中(225万株/hm2)、高(300万株/hm2)3个种植密度对适度晚播(10-26)冬小麦花后氮素代谢和氮素利用的影响。【结果】与正常播期(10-15)冬小麦相比,晚播冬小麦旗叶硝酸还原酶活性和可溶性蛋白含量较高,但因生育期缩短,其全株氮素积累量、籽粒含氮量、产量和氮素利用效率均有所降低。晚播冬小麦中、高密度处理旗叶的硝酸还原酶和谷氨酰胺合成酶活性及旗叶可溶性蛋白含量较高,且中密度处理叶片含氮量、籽粒和全株氮素积累量较高。最终,中、高密度处理的籽粒产量和氮素利用效率高于低密度处理。【结论】在本试验条件下,"新麦18"在适度晚播条件下兼顾高产和高效利用氮素的适宜播种密度为225万株/hm2。

[Objective] Effects of plant density on nitrogen metabolism and nitrogen use efficiency of late sown winter wheat were studied to provide a basis for high-yield and efficient use of nitrogen fertilizer of late sown winter wheat in Yellow and Huai Valley in China.[Method] We conducted an experiment to study the effects of plant density on nitrogen metabolism and nitrogen use efficiency of late sown winter wheat in 2007-2008.[Result] The results showed that,compared with normal sowing（October 15）,late sowing（October 26） enhanced the activity of nitrate reductase and the soluble protein content in flag leaf.However,the nitrogen accumulation amount of whole plant,nitrogen concentration of grain,grain yield and nitrogen use efficiency of that were reduced because of shorter growing period.Under the condition of late sowing,the activity of nitrate reductase,glutamine synthetase,the soluble protein content in flag leaf was higher under medium plant density（225×10^4 plants/hm^2） and high plant densities（300×10^4 plants/hm^2） than that under low density,so were the leaf nitrogen content,the contribution of translocation nitrogen to grain nitrogen accumulation.Thus,grain yield and nitrogen use efficiency under medium and high plant densities（300×10^4 plants/hm^2） were higher than that under low density.[Conclusion] In the areas with the condition similar to this experiment,when considering both yield and grain quality,Xinmai 18 is suggested with the densities 225×10^4 plants/hm^2 for moderate late sowing.