Physiological Response of the Leaves of Wild Flower Sanguisorba offiicinalis L.to Simulated Acid Rain

[Objective] The purpose was to study the injury effects of simulated acid rain on the leaves of Sanguisorba offiicinalis L.[Method] With 2-year-old S.offiicinalis plant as the tested material,the analytically pure sulfate and nitric acid were used to prepare into the mother liquor of simulated acid rain which was diluted into 5 kinds of water solution with different pH to spray the plant.The various physiological indexes of leaves were determined after spraying for 24 h.[Result] The leaves treated by the simulated acid rain with pH of 2.0 and 3.5 showed visible injury spots to various extent.The leaves treated by the simulated acid rain with pH of 2.0,3.5 and 4.0 made the reduction of chlorophyll content and pH value in juice in leaves.The treatment with all the simulated acid rain treatment caused the strengthening of cell membrane permeability,the increase of MDA content,soluble carbohydrate content and POD activity and the decrease of SOD activity.The pH value in leaves had a extremely significant negative correlation to conductivity,MDA content and POD activity,there were the extremely significant correlation between MDA and POD as well as POD and SOD,and there were the extremely significant positive correlation between chlorophyll content and soluble carbohydrate content.[Conclusion] The physiological activities were more sensitive than visible leaf injury to acid rain.