Abstract: In a series of laboratory trials,this paper studied the responses of eggplant (Solanum melongena),the host plant of carmine spider mite Tetranychus cinnabarinus,to different pH values simulated acid rain.The results showed that with the increasing acidity of simulated acid rain,the CAT activity and the contents of P and soluble protein in egg plant leaves increased significantly first,reaching the highest at pH 4.0 or 3.0,and then decreased; while the POD activity and soluble sugar content were in adverse.The reduced sugar content and SOD activity of eggplant leaves increased,but the pH value decreased with increasing acidity of acid rain.Acid rain had no effect on leaf water content.Among the test indices,leaf POD was most insensitive to the acid rain,followed by leaf pH,SOD and CAT,while the others were very sensitive.Weak acid rain (pH > 4.0) promoted the protective ability of eggplant leaf and its growth,and the growth of T.cinnabarinus was also promoted because of the changed contents of soluble sugar,P and soluble protein in eggplant leaves being more favorable to its eating; while strong acid rain (pH<3.0) inhibited the growth of both host plant and mite.

Key words: Shadow width, Relative light illuminance, Leaf area density function, Light wakening coefficient