采用开顶式气室(Open Top Chambers)进行水培试验,以两种氮效率玉米(ZeamaysL.)基因型为供试作物,通过不同大气NH3浓度处理,测定苗期各叶绿素荧光动力学参数。结果表明,供氮介质和大气NH3浓度升高对两种氮效率玉米基因型的初始荧光值(Fo)不存在显著影响。高供氮介质下,在NH3浓度升高时,氮高效5号基因型的最大荧光产量(Fm)和可变荧光(Fv)均显著减小(p<0.05),而氮低效基因型四单19的Fm、Fv值显著增加;低供氮介质下,大气NH3浓度升高对2种基因型Fm、Fv值的影响结果与高供氮介质时相反。说明大气NH3浓度升高对生长在高供氮介质下的氮高效5号基因型有一定的抑制作用,而对氮低效基因型四单19有一定程度的促进作用。在不同供氮介质下,大气NH3浓度升高时,两种氮效率玉米基因型的qN、qP值减小,说明大气NH3浓度升高时,作物对光合机构的保护能力比大气背景NH3浓度时弱。
Function of canopy in changing nutrient cycle and flux is one of the focuses in recent years. On the basis of comprehensively appraising published research, we analyzed the nitrogen loss leaching from plant canopy and several factors which affected it. We pointed out the disadvantages of the published researches and the key issues that ought to be solved： （1） The menstruation need to be advanced, and the research should be carried out on nitrogen loss leaching from the canopy of the field plant. （2） If the nitrogen is leached from the plant canopy, the research on the type of nitrogen loss should be carried out, and the nitrogen use efficiency of different varieties should be dealt on a research perspective with regard to the nitrogen leaching. （3） The research should be conducted on the mechanism and pathway, and the progress of nitrogen leaching; and the factors affecting nitrogen leaching should be included in the research, such as the leaf area of different growth stages, stomata densities, stomata conductance, and the apparent free space, which are beneficial to explain the mechanism of nitrogen leaching from the plant canopy.
LI Shi-qingJI Chun-rongFANG Ya-ningCHEN Xiao-liLI Sheng-xiu
