摘 要 ：采用开顶式气室（Open Top Chambers）进行水培试验，以两种氮效率玉米(Zea mays L.)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。
Abstract:The objective of this experiment was to compare the effect of atmospheric NH3 and N levels in a hydroponic solution on the chlorophyll fluorescence of two corn genotypes with different nitrogen use efficiencies. The hydroponic experiments were carried out in open top chambers. Chlorophyll fluorescence measurements were made at the seedling stage. The results showed that the Fo value of the two corn genotypes was not significantly affected by nitrogen levels in the hydroponic solution or increased atmospheric NH3 concentrations. Both the Fm and the Fv value of the high nitrogen use efficiency genotype (NE5) were significantly (p<0.05) lower in the high solution N + high atmospheric NH3 treatment compared to the high solution N + normal atmospheric NH3 treatment. In contrast, Fm and Fv of the low nitrogen efficiency genotype (SD19) were significantly higher in the high solution N + high atmospheric NH3 treatment compared to the high solution N + normal atmospheric NH3 treatment. Both Fm and Fv in the low solution N + high atmospheric NH3 treatment were lower compared to the high solution N + increased atmospheric NH3 treatment. This indicated that at high solution N levels, increased atmospheric NH3 concentrations had a negative effect on NE5, but a positive effect on SD19. The results also showed that the qN and qP value of the two corn genotypes decreased under different nitrogen levels and increased atmospheric NH3 concentrations. This indicated that the protection function of crops on photosynthesis was lower under high atmospheric NH3 compared to normal atmospheric NH3 concentrations.