近地层大气臭氧对水稻光合作用影响的数值模拟

Simulation of the impact of ozone on rice canopy photosynthesis

利用TE 4 9C型臭氧自动观测仪测定了常熟稻田上方O3 浓度 ,并利用OTC 1型开顶式气室测定了O3 浓度对水稻叶片光合速率的影响 .在此基础上建立了O3 对水稻冠层光合影响的数值模式 ,模式具有较高分辨率和准确度 .观测表明 :O3 浓度逐时值变化幅度在 0～ 16 0× 10 -9之间 ,而日平均值变化仅在 5× 10 -9～ 6 0× 10 -9范围内 ;稻田上方O3 存在高浓度单峰型和低浓度平缓型两种典型日变化 .数值分析表明 :全晴天时高浓度单峰型对光合日总量影响较大 ;随日总辐射量加大臭氧浓度增加对光合作用影响程度加强 .全生育期积分表明 :受O3 影响水稻光合作用总损失量约为 11 6 % .

The O\-3 concentration above the rice paddy field was observed hour-by-hour with TE-49C ozone automonitor in Changshu. The impact of O\-3 on the rice leaf photosynthesis was measured in the OTC-1 open top chamber. Based on the observed parameters, a numerical model for simulating the impact of O\-3 on rice canopy photosynthesis was established. The results of O\-3 observation showed that there are two typical patterns of O\-3 diurnal variation in the Yangtze River Delta during rice growth periods, including the unimodal curve with high concentration and smooth variation curve with low concentration. The simulation result identified that the unimodal variation with high concentration has great impact on daily canopy photosynthesis, and the impact of O\-3 becomes more intense as radiation increased. The accumulated lost of photosynthesis is about 11\^6% in the growth period under suitable moisture and fertilizer conditions.