Effect of simulated acid rain on physiological characteristics of blueberry leaves

The effect of simulated acid rain on blueberry leaf physiological characteristics was studied by using two-year old half-high blueberry St.Cloud and leaf spray four levels of pH simulated acid rain,which was prepared by analytically pure sulfate and nitric acid.The results showed that leaf chlorophyll content and SOD activity were decreased with the acid rain stress levels increasing and time extension,but leaf SOD activity was higher than that of CK in all periods at pH 5.5 treatment;leaf POD activity was increased with the acid rain stress levels increasing and time extension,but it was changed slightly at pH 5.5 and pH 4.5 treatment;leaf MDA and soluble sugar content were increased with the acid rain stress levels increasing and time extension.However,all the above leaf physiological characteristics recovered rapidly to the control level after simulated acid rain removing.Slight and mediun acid rain stress increased leaf physiological activity,which indcated that blueberry plants had the ability of strong acid rain resistant.