大气臭氧浓度升高对农作物产量的影响

Study on the Impact of Elevated Atmospheric Ozone on Crop Yield

大气O3浓度升高对农作物产量的影响是评估大气O3造成农作物减产及经济损失的基础．分别在北京和广东东莞建立OTC（田间开顶式气室）系统，开展大气O3对大田冬小麦和水稻的影响研究，在整个生长期对作物进行O3熏蒸，计算O3暴露量，获得冬小麦和水稻产量与O3暴露量之间的响应关系．结果表明：东莞水稻临界水平（以AOT40计，AOT40为大于40nL／L的小时平均φ（O3）与40nL／L差值的累计值）为4．95μL／（L·h），而北京冬小麦为2．44μL／（L·h）．根据我国已有农作物O3暴露量-产量响应关系计算可知，我国水稻和冬小麦的AOT40分别为4．950～9．506和2．280～3．858μL／（L·h），水稻对O3的敏感性从我国北方到南方呈逐渐增加态势，但冬小麦对O3敏感性并无明显的地域变化规律．在大田环境大气妒（O3）条件下，东莞水稻相对产量损失为2．70％[AOT40=2．68μL，（L·h）]，北京冬小麦的相对产量损失为12．85％[AOT40=6．72μL／（L·h）]．我国农作物生长环境多样，作物种类繁多，需要继续开展试验研究来建立本地化O3暴露量一产量响应关系，用于合理评估区域农作物产量损失．

Understanding the impact of elevated ozone （ O3 ） on crop yield is helpful for evaluating the yield loss and economic loss induced from atmospheric 03 pollution. Open Top Chamber （OTC） systems, established in Beijing and Dongguan, Guangdong Province, were implemented to study the impact of different concentrations of O3 on the winter wheat and rice, respectively. The crops were fumigated with O3 during their whole growth period. The exposure indices were calculated, and the response relationship between the exposed quantity of O3 and the yield of rice or winter wheat were obtained. The results showed that the critical level （based on AOT40, AOT40 is the hourly meanozone concentration accumulated over a threshold ozone concentration of 40 nL/L） of the rice were 4. 95 μL/（ L. h） in Dongguan and 2. 44 μL/（L.h） for winter wheat for Beijing. Critical levels for crop in China were calculated based on the relationship between the exposed quantity of O3 and the yield of crops in previous studies. The critical levels were 4. 950-9. 506 μL/（Loh） and 2. 280- 3. 858 μL/（L-h） for the rice and winter wheat in China, respectively. The sensitivity of rice to the atmospheric O3 increased from the North to the South of China, while that of winter wheat not significantly changed between different regions. Under the current environmentalφ（ O3 ） condition, the relative yield loss was 2.70% （ AOT40 = 2.68 μL/（ L· h） ） for the rice in Dongguan and 12.85% （AOT40 =6.72 μL/（L·h） ） for the winter wheat in Beijing. There are various crop growing environments and numerous crop categories in China, thus more studies should be conducted to establish O3 local exposed quantity-yield response relationships and further to reasonably assess the loss of regional crop yield.