Abstract: With pot experiment,this paper studied the membrane lipid peroxidation and the variations of antioxidation system in Cynodon dactylon under recirculated landfill leachate irrigation.The results showed that when irrigated with low dilution ratio (<25%) leachate,the chlorophyll a/b ratio increased with increasing dilution ratio,cell membrane permeability and MDA and H₂O₂ contents were in adverse,and membrane lipid peroxidation was relatively weak.However,with the increasing leachate dilution ratio (＞25%),there existed an obvious negative effect onCynodon dactylon,i.e.,the chlorophyll a/b ratio decreased,while cell membrane permeability and MDA and H₂O₂ contents increased,which meant that the membrane lipid peroxidation was accelerated.The contents of antioxidants AsA,GSH and Car also showed the similar trend,i.e.,they increased with increasing leachate dilution ratio when irrigated with low dilution ratio leachate,but decreased under medium or high dilution ratio leachate irrigation.Among three test anti-oxidative enzymes,SOD and POD activities showed a similar change to test antioxidants, and POD activity was more sensitive,while CAT activity was on the contrary.The contents of test antioxidants and the activities of SOD and POD were negatively and significantly correlated to MDA content,indicating that they might play an important role in preventing Cynodon dactylon from cell membrane lipid peroxdation.

Key words: Pinus massoniana, Temperature, Precipitation, Relative humidity, Climate change