Effects of simulated acid rain on photosynthetic characteristics of gas exchange and yield of field-grown spring wheat at the booting stage

To investigate the effects of acid rain on photosynthetic characteristics of spring wheat at the booting stage,plants were sprayed with simulated acid rain at pH levels of 1.5,2.5,3.5,4.5,or 5.6.Yield and photosynthetic parameters of the spring wheat leaves were monitored.1) The effects of simulated acid rain on photosynthetic characteristics of spring wheat leaves increased as the hydrogen ion concentration increased.2) The pH values of simulated acid rain were significantly positively correlated with net photosynthetic rate,stomatal conductance,transpiration rate,water use efficiency,relative chlorophyll content,and yield,which in turn,were significantly negatively correlated with intercellular CO2 concentration.