This study was conducted to measure the changes of electrolyte leakage(EL) and the activities of superoxide dismutase(SOD) during cold acclimation on alfalfa(Medicago sativa).The cold acclimation of alfalfa was described by the median lethal temperatures(LT_(50)) of alfalfa leaves.The measurement results indicated that the EL of alfalfa tissue under low-temperature treatments presented a curve change like S fitted Logistic Function.During cold acclimation LT_(50) of alfalfa declined(8.7) ℃,from-6.9 ℃ of ear...