中文摘要：

该试验采用开顶式气室（Open top chambers）装置，在两种大气NH3浓度水平（大气背景浓度值为10nl·L^-1和高NH3浓度1000nl·L^-1）和两种供氮介质水平（高供氮介质和低供氮介质）下，对两种氮效率玉米（Zea mays）基因型（‘氮高效5号’（NE5）和‘氮低效四单19’（SD19））的叶绿素指标值（SPAD值）、净光合速率（Pn）、气孔导度（Gs）、生物量和根冠比等生物学和生理学指标进行了测定。结果表明，大气NH3浓度升高对两种氮效率玉米基因型各生理指标有显著影响（P〈0．05）。与大气背景NH3浓度相比，当大气NH3浓度为1000nl·L^-1时，生长在高供氮介质中‘氮高效5号’的SPAD值、Pn和Gs分别降低7．0％、14．0％和6．5％，而‘氮低效四单19’的对应指标分别降低9．0％、11．0％和6．9％；生长在低供氮介质中的两种氮效率玉米基因型各生理指标均显著增加（P〈0．05）：‘氮高效5号’的SPAD值、Pn和Gs分别增加5．7％、7．1％和17％，‘氮低效四单19’的对应指标分别增加7．0％、11．0％和22．0％。高供氮介质中NH3浓度升高对氮低效基因型玉米冠层生物量抑制作用小于对氮高效基因型玉米的抑制效应，而低供氮介质中NH3浓度升高对氮高效基因型玉米冠部的促进作用显著高于对氮低效基因型玉米的促进作用（P〈0．05）；两种大气NH3营养下玉米根冠比的变化与采样时期有关。说明从大气中吸收NH3有利于改善生长在低供氮介质上玉米的氮素营养状况，而且对氮低效基因型玉米的促进作用比对氮高效基因型玉米更加显著。

英文摘要：

Aims The main aim of this study was to investigate the response of various physiology indexes, e.g., chlorophyll index value （stand for the relative content of chlorophyll, SPAD value）, net photosynthetic rate （Pn）, stomatal conductance （Gs）, and mot shoot ratio （R/S） in two genotypes of maize （ Zea mays） to NH3 concentration enrichment. Methods We grew maize on Hoagland solution in PVC pots in open top chambers （OTCs）. The experiment was a split-split plot design, which main treatments were two NH3 concentrations （ 10 and 1 000 nl·L^-1 ）. The atria-plot treatments of the experiment were two levels of nitrogen （high and low）, and sub-sub-plot treatments were two N efficiency genotypes （high N efficiency, ‘NE5＇, and low N efficiency, ‘SD19＇ ）. Air flow in OTCs was controllod by small fans and atmospheric NH3 concentration was measured accurately by two methods （NH3 detemtination tubes and GTL-C atmosphere detecting apparatus）. Important findings Under elevated atmospheric NH3, there were significant differences （p 〈 0. 05） for physiology indexes between the two varieties, ‘NE5＇ and ‘S D19＇. Under high N medium, compared with 10 nl·L^-1 atmospheric NH3 concentration, the SPAD value, Pn and Gs of ‘NE5＇ treated with 1 000 nl·L^-1 decreased 7.0%, 14.0% and 6.5%, respectively, and the corresponding targets of ‘SD19＇ decreased 9.0%, 11.0% and 6.9%, respectively. Under low N medium, various physiology indexes of the two varieties significantly increased, i.e., the SPAD value, Pn and Gs of ‘NE5＇ increased 5.7%, 7. 1% and 17%, respectively, and the relative value of ‘SD19＇ increased 7.0%, 11.0% and 22.0%, respectively. The results also demonstrated that under high N medium, the inhibition effect of increased atmospheric NH3 on ‘SD19＇ shoot biomass was obviously lower than that of ‘NE5＇, while under low N medium, NH3 concentration enrichment had more positive influence on ‘NE5＇ （p 〈 0. 05） than ‘SD19＇. Moreover, the rat