Effects of salt stress on membrane lipid peroxidation and protective enzyme systems in Eucalyptus seedlings

The membrane lipid peroxidation and protective enzyme systems in the leaves of different varieties of E.urophlla?grandis and E.grandis,such as DH3229,DH3327,T13,and A4,were studied under salt stress.The results showed that ion leakage and MDA content in membrane increased as NaCl concentration increased.The activities of SOD,POD,and CAT increased in low NaCl concentration,and then decreased with increasing NaCl concentrations.There was no significantce difference in SOD activities among the varieties.However,in the range of 0.034~0.136 mol·L-1 NaCl,the POD activity was significantly higher in DH3229 than other varieties.CAT activity was higher in T13 than others under 0.034 mol·L-1 NaCl treatment.