To evaluate the nitrogen use efficiencies (NUE ) and their relationships with nitrogen nutritious character-istics of naked oats with eight different genotypes ,a field experiment was conducted .Samples were collected at different growth stages and were then separated according to the tissue origins .After being dried ,the samples were weighed and the nitrogen concentration was determined using semi-micro Kjeldahl method .The main results showed that the genotypes had significant effects on NUE ( CV 11 .98% ~26 .65% ) but not on NHI ( CV 5 .04% ) .Additionally ,NFE ,as an in-tegrated index reflecting the differences of grain yield and nitrogen utilization among different oat varieties ,was signifi-cantly ( P<0 .05;P<0 .01 ) correlated with NRE ,NPP ,indicating that it could be more useful in evaluating NUE . Moreover ,NFE could be improved by increasing N assimilation and translocation after anthesis to effectively increase the N utilization in oat ( r=0 .7233* * , r=0 .7053* *) .Also ,it was found naked oat could endure soil impoverishment ( r=0 .484*) .However ,excessive nitrogen was harmful ( r= -0 .701* *) .This research indicated that top-dressing nitrogen before anthesis could improve NUE effectively .At the same nitrogen levels ,significant genotype effects of NRE and NFE caused remarkable differences among varieties ,providing a rich variation basis for oat breeding .%为系统研究裸燕麦氮效率，选用8个不同基因型裸燕麦种质进行田间试验，在不同生育期对不同氮素利用效率指标的基因型差异及裸燕麦的氮素营养特性进行分析。结果表明：（1）各基因型间除氮收获指数变异相对较小（ CV 5．04％）之外，其余指标均变异较大（ CV 11．98％～26．65％）；（2）氮流效率与氮素吸收效率、植株氮生产力呈显著（ P＜0．05）、极显著（ P＜0．01）相关关系，说明植株干物质生产与氮素利用的关系密切，可作为表征裸燕麦籽粒蛋白含量高低的综合指标，对高蛋白裸燕麦育种具有重要价值；（3）提高花后氮同化量和氮转运量有利于提高氮流效率（ r＝0．7233**，r＝0．7053**）；（4）裸燕麦开花期前追施氮肥可有效提高氮素吸收效率（ r＝0．484*），花后土壤供氮水平过高不利于植株干物质积累（ r＝－0．701**）。研究表明裸燕麦氮效率基因型效应显著，为氮高效育种提供了丰富的变异材料。
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