Effects of Simulated Acid Rain and Pb Combined Stress on Growth and Antioxidative Physiology of Two Kinds of Turf Grass

[Objective] The aim was to explore the effects of simulated acid rain and Pb combined stress on growth and antioxidative physiology of Festuca arundinacea Schreb.and Lolium perenne.[Method] Effects of simulated acid rain(pH 3.5,4.5 and 5.6) and Pb(0,500,1 000 and 1 500 mg/kg) combined stress on the biomass,chlorophyll content,malondialdehyde(MDA) content,superoxide dismutase(SOD) activity,peroxidase(POD) activity,soluble sugar content and electric conductivity of F.arundinacea and L.perenne were studied by pot experiment.[Result] The biomass and chlorophyll content of F.arundinacea and L.perenne both decreased with the increase of simulated acid rain and Pb concentration,and the lowest values appeared when pH was 3.5 and Pb concentration was 1 500 mg/kg.The activities of SOD and POD in leaves increased and then decreased with the increase of simulated acid rain and Pb concentration.The contents of MDA and soluble sugar and the electric conductivity gradually increased with the increase of simulated acid rain and Pb concentration,and the maximum value appeared when pH was 3.5 and Pb concentration was 1 500 mg/kg.[Conclusion] Both F.arundinacea and L.perenne deal with the combined stress of simulated acid rain and Pb through adjusting antioxidant enzymes system and increasing soluble sugar content.However,the growth of F.arundinacea and L.perenne are obviously inhibited under the combined stress of high-acidity simulated acid rain and high-concentration Pb,and F.arundinacea shows good resistance to the combined stress of low-acidity acid rain and low-concentration Pb.