不同氮效率玉米基因型苗期对光和氮响应的研究

对氮效率表现差异显著的3个玉米自交系幼苗采用不同光强和氮浓度处理,比较根冠比、生物产量、硝酸还原酶和谷氨酰胺合成酶的响应差异.结果表明:不同氮效率自交系对不同氮浓度与光照强度处理的响应存在显著差异;氮低效材料在低光低氮条件下的生物产量表现比氮高效材料好,在高光高氮条件下时生物产量表现比氮高效差;氮高效材料随着氮浓度增加比氮低效材料更能保持根的发达性,发达的根系是氮高效的保证.不同氮效率自交系生物产量、硝酸还原酶和谷氨酰胺合成酶光氮最佳耦合点的值不同,氮低效自交系出现光氮最佳耦合点时所需要的氮浓度(或光强)要比氮高效自交系低.因此,玉米基因型氮效率的发挥不但需要适宜的供氮水平,还需要合适的光照强度.

The response of three maize inbred seedling with the different nitrogen use efficiency to light and nitrogen

Based on the hydroponic culture methods, the responses of the biomass, shoot/root ratio, the nitrate reductase activity and glutamine synthetase activity of 3 maize inbred seedlings with different nitrogen use efficiency to 3 levels of light intensity and 3 levels of N supply were studied. The results showed that the difference of the response of the seedling biomass, shoot/root ratio, the nitrate reductase activity and glutamine synthetase activity among 3 maize inbreds was significant. The biomass of maize seedling with lower nitrogen use efficiency was higher than that of maize seedling with higher nitrogen use efficiency under low nitrogen and light intensity condition, but it was lower under high nitrogen and light intensity condition. The root growth of maize seedling with higher nitrogen use efficiency was better that of maize seedling with higher nitrogen use efficiency. The best combination of nitrogen and light intensity for the biomass and nitrate reductase activity were different among 3 maize inbreds with different nitrogen use efficiency and the maize inbrd with low nitrogen use efficiency need less nitrogen or lower light intensity than the maize inbred with high nitrogen use efficiency. In conclusion, the appearance of nitrogen use efficiency for maize inbreds is not only related to the nitrogen supply but also to the light intensity.