Stress Effects of Simulated Acid Rain on Photosynthetic Characteristics and Yield of Field-grown Spring Wheat at the Filling Stage in Semi Arid Rain Feed Region

In order to investigate the effect of acid rain on photosynthetic characteristics of spring wheat,spring wheat at the filling stage was sprayed with simulated acid rain at different pH level of 1.5,2.5,3.5,4.5 and 5.6,and then,the yield and the photosynthetic parameters of spring wheat leaves were monitored.The results indicated:①The net photosynthetic rate reduces in the range of 9.61% to 61.50%,stomatal conductance reduces in the range of 7.03% to 57.46%,transpiration rate reduces in the range of 3.70% to 55.44%,intercellular CO2 concentration increases in the range of 27.91% to 43.74%,the chlorophyll relative content reduces in the range of 12.12% to 41.92%,the yield of spring wheat reduces in the range of 15.50% to 37.05%.Effect of simulated acid rain on photosynthetic characteristics of spring wheat leaves increases more and more remarkable with the increase of hydrogen ion concentration.②The pH values of simulated acid rain was significantly positively correlated with net photosynthetic rate,transpiration rate,stomatal conductance,the relative chlorophyll content and the yield,and the pH values of simulated acid rain was significantly negatively correlated with intercellular CO2 concentration.