Effect of Low Temperature on Membrane Leakage and Lipid Peroxidation in Muskmelon Seedling Leaves

Two muskmelon cultivars,Zaojin and Elizabeth were treated under different low-temperatures. The membrane permeability, MDA,activity of SOD,CAT,POD were determined on the 1,4,7 and 10 day after being treated. The results showed that the effects of critical temperature(15℃/8℃)on membrane permeability and MDA contents increased in both cultivars was more significant than that of lower temperature (30℃/20℃ and 21℃/12℃).The activity of SOD,POD and CAT in Zaojin increased while time prolonging in some extent.However,out of the extent,all protected enzyme activities decreased while time prolonging.Under any temperature,the membrane permeability and MDA content of Elizabeth were less than Zaojin,the protected enzyme activities of Elizabeth were more steadier than Zaojin.It suggested that the membrane permeability,MDA and activity of SOD,CAT and POD can be used as target for identifying cold-tolerance cultivars.