[目的]研究在不同氮素水平条件下,不同氮效率玉米品种的物质积累及氮代谢相关酶活性的差异.[方法]采用水培方式,选用氮高效玉米品种郑单958和氮低效玉米品种鑫鑫1号为供试品种,设置5个施氮浓度(N1～N5),分别为0.04、0.80、2.00、4.00和8.00 mmol/L,揭示不同品种氮效率差异的生理机制.[结果]随着施氮量增加,玉米幼苗的干物质积累不断升高,叶面积、总根长、根表面积和根体积逐渐增加,当施氮量为4.00 mmol/L(N4)时,以上指标达到最大.2个品种相比,氮高效品种郑单958效果好于鑫鑫1号.施氮量为8.00 mmol/L(N5)时株高最高.随着施氮量增加,硝酸还原酶(NR)和亚硝酸还原酶(NiR)活性逐渐升高,但N3、N4和N5这3个处理相同品种的酶活性增加幅度较小.谷氨酸合成酶(GOGAT)和谷氨酰胺合成酶(GS)活性先上升后下降,N3处理时,2个品种活性最高.[结论]氮高效品种郑单958在不同的氮水平下有较高的氮代谢酶活性,这有利于氮肥的转化吸收和利用,从而有利于植株生长和物质积累.%[Objective] To research the difference of dry matter accumulation and nitrogen metabolism enzyme activity of different nitrogen efficiency maize varieties in different nitrogen levels.[Method] Hydroponics was used in the research,high efficient nitrogen fertilizer cultivar (Zhengdan 958) and low efficient nitrogen fertilizer cultivar(Xinxin 1) were selected in the research and five nitrogen levels (N1 ～ N5) were set (0.04,0.80,2.00,4.00 and 8.00 mmol/L)to uncover the physiological mechanism of different nitrogen efficiency in different maize varieties.[Result] With the increase of nitrogen application,dry weight accumulation was increased continuously and leaf area,total root length,root area and root volume were increased.The maximum value appeared in 4.00 mmol/L (N4).Compared to Xinxin 1,Zhengdan 958 was better in above indicators.The biggest leaf area appeared in 8.00 mmol/L (N5).With the increase of nitrogen application,NR and NiR activity were increased.The enzyme activity of same variety was less increase in N3,N4 and N5 treatments.GOGAT and GS activity showed first rising and then declining trend,and the highest activity of three varieties appeared in N3 treatment.[Conclusion] Zhengdan 958 shows higher nitrogen metabolism enzyme activity in different nitrogen efficiency maize varieties of different nitrogen levels,which is good for absorption,transformation and utilization of nitrogen as well as growth and matter accumulation of maize.
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