Regulation functions of Ca~(2+) physiological of Zephyranthes candida under simulated acid rain stress

The objective of this experiment is to study the effect of simulated acid rain at different pH levels on physiological of Zephyranthes candida Herb.and the regulation function of Ca2+.With pot experiments,this paper studies the effect of simulated acid rain that included 5 different pH levels(pH 2.0,2.5,3.0,4.0 and 5.6) and the regulation function of Ca2+ on the organic matter metabolism,and membrane damage,and antioxidant enzyme activity,Chl content,and gas exchange parameters of Zephyranthes candida leaves.With the decrease of the pH,value of REC,MDA and SOD,increased gradually while value of soluble protein,soluble sugar,POD,Chl and Pn decreased gradually,Gs and Ci were firstly increased and then significantly reduced in pH2.0;when pH≤4.0,there was a significant correlation between Soluble sugar-pH meanwhile there were significant correlations between SOD-pH and Pn-pH.However,under the same acid rain coercion in the leaves pretreated with 10 mmol/L Ca(NO3)2,soluble protein,soluble sugar,POD,SOD and Chl,Pn increased of different level,and REC,MDA reduced significantly;each index did not change significantly with the pH lowing.Under simulated acid rain stress,pretreated with Ca2+could strengthen various physiological function of Zephyranthes candida Herb.,thus reduced the damage by acid rain.Experiments have found that the regulation effects of Ca2+ was more apparent in pH≤3.0.