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利用开顶式气室(OTC)开展了大田实验条件下地表臭氧浓度增加对灌浆期冬小麦光合日变化影响的实验研究。结果表明:13:00—15:00大田环境变量(光合有效辐射、温度、水气压差)对冬小麦光合作用产生了胁迫;与对照组相比,100和150nl·L-1臭氧熏气下净光合速率平均下降了6.3%和11.1%(P<0.05);100nl·L-1臭氧熏气下气孔限制值、蒸腾速率、气孔导度、水分利用率变化趋势与对照组基本一致,但在150nl·L-1臭氧熏气下,11:00之前蒸腾速率和气孔导度均显著增加,水分利用率显著下降,13:00—15:00,水分利用率显著增高;在无环境胁迫条件下,100和150nl·L-1臭氧熏气分别对冬小麦光合作用产生了气孔限制和非气孔限制,导致光合速率下降。环境变量胁迫下,100和150nl·L-1臭氧熏气均显著提高了冬小麦的水分利用率,且150nl·L-1臭氧熏气显著提高了进入气孔用于光合作用的二氧化碳比例。
The open-air chamber (OTC) was used to study the effect of surface ozone concentration on photosynthetic diurnal variation of winter wheat under field experiment. The results showed that the environmental variables (photosynthetically active radiation, temperature and water pressure difference) in 13:00 to 15:00 caused stress on the photosynthesis of winter wheat. Compared with the control group, 100 and 150 nl·L-1 of ozone Photosynthetic rate decreased by 6.3% and 11.1% on average (P <0.05). The changes of stomatal limitation, transpiration rate, stomatal conductance and water use efficiency of 100nl·L-1 ozone were basically consistent with those of the control group. Under the condition of L-1 ozone fumigation, the transpiration rate and stomatal conductance increased significantly before 11: 00, the water use efficiency decreased significantly, and the water use efficiency increased significantly from 13: 00-15: 00. Under the condition of no environmental stress, Ozone fumigation with 100 and 150 nl·L-1, respectively, had stomatal and non-stomatal limitations on the photosynthesis of winter wheat, resulting in a decrease in photosynthetic rate. Under the environmental variables, 100 and 150 nl·L-1 of ozone fumigation significantly increased the water use efficiency of winter wheat, and 150 nl·L-1 ozone fumigation significantly increased the proportion of carbon dioxide entering the stomata for photosynthesis.