Effects of simulated acid rain on photosynthetic characteristics and yield of spring wheat at flowering stage

Spring wheat at flowering stage was sprayed with simulated acid rain at different pH levels 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 indicate: The net photosynthetic rate reduces in the range of 24.20%～58.23%,stomatal conductance reduces in the range of 35.90%～58.37%,transpiration rate reduces in the range of 36.70%～56.69%,intercellular CO2 concentration increases in the range of 73.26%～101.06%,the chlorophyll relative content reduces in the range of 1.96%～15.99%,and the yield of spring wheat reduces in the range of 12.54%～32.53%.The effect of simulated acid rain on photosynthetic characteristics of spring wheat leaves increases more and more remarkable with the increase of hydrogen ion concentration.The pH values of simulated acid rain are significantly positively correlated with net photosynthetic rate,transpiration rate,stomatal conductance,relative chlorophyll content and the yield,while they are significantly negatively correlated with intercellular CO2 concentration.