中文摘要：

本文利用开顶式气室研究了O3浓度升（80nmol／mol）对小麦（Triticum aestivum L）光合作用和产量的影响，揭示O3对作物的伤害机理。结果表明，O3浓度升高使小麦净光合速率、胞间CO2浓度、气孔导度和蒸腾速率均比对照有所下降，最大降幅分别为40．27％、37．06％、30．17％和30．92％，说明O3通过降低小麦胞间CO2浓度、气孔导度及蒸腾速率影响其光合速率；Hill反应活力和叶绿体Ca^2＋/Mg^2＋-ATP酶活性降低，与对照相比均达到显著（P〈0．05）或极显著（P〈0．01）水平；电镜下观察到叶肉细胞细胞壁断裂、质壁分离；叶绿体松散外漏、片层解体，这些都是O3伤害的结果；从产量构成来看，小麦穗长、千粒重、粒重和穗粒数明显降低。以上现象说明O3浓度升高对小麦的光合作用有抑制效果，并且这种效果最终表现在产量上。

英文摘要：

Effects of elevated O3 exposure （80nmol/mol） on photosynthesis and yield in wheat was studied in open-top chambers to review the injury mechanism of crop to elevated O3 exposure. The results showed that elevated O3exposure results in lower net photosynthetic rate（Pn）, intercellular CO2 concentration（Ci）, stomatal conductance （Gs） and transpiration rate（Tr）, which decreased 40.27% ,37.06% ,30.17% and 30.92% compared to control and showed that O3 decreased Ci, Gs and Tr in order to influence Pn. The activities of Hill reaction and Ca^2＋/Mg^2＋-ATPase in chloroplast reduced and attained significance level （p 〈 0.05 ）, or highly significance level （ p 〈 0.01 ）. In addition, these phenomena was detected under elevated O3 exposure： the leaf cell wall of wheat ruptured and is separated from cytoplasm, chloroplast and its grana lamellae in leaf cells are disorganized. All these phenomena due to highly O3 concentration. A remarkable reduction in the length of spike, 1000-grains weight, grain weight and grain number per spike was also observed. All the results suggested that elevated O3 exposure restrains the photosynthesis and decreases the yield in wheat ultimately.