Four rice cultivars were taken as tested materials to measure the physiological indexes at the seedling stage under the artificially low temperature condition.The results showed that Zhuliangyou 505 was characteristic on cold toler-ance.Electrolyte leakage and MDA decreased,chlorophyll and soluble protein content increased,SOD activity enhanced in normal growth condition.It indicated that Zhuliangyou 505 seedlings returned to normal growth.Zhongjiazao 17 was charac-teristic on cold sensitivity.Electrolyte leakage and MDA increased significantly under cold stress and maintained high lever in no...