Methods: SC124 and Fuxuan 01, two cold-resistant cassava cultivars and Nanzhi199 and SC205, another two cold-sensitive cassava cultivars were studied under low temperature stress. Aims: in order to explore the hardy physiological characters of different cassava cultivars. Results: Results showed that under low temperature stress, the cell membrane permeability of the tested cassavas increased, the increase ranges in the cold-sensitive cultivars were more obvious than those in the strong cold resistance ones; the MAD contents in leaves were in a rise-fall sequence while the MAD contents in the cold-sensitive cultivars were much higher than those in the cold-resistant ones; under low temperature stress, the SOD and POD activities in leaves of cold-sensitive cultivars dropped greater than those in the strong cold-resistant ones; the contents of proline, soluble sugar and soluble liquid protein in leaves increased more seemingly in the cold-resistant cultivars than in the cold-sensitive ones. The contents of soluble sugar and soluble liquid protein in leaves were in a rise-fall trend as the temperature dropped and time elapsed. There was a dramatic decline in the chlorophyll contents and water ratios in leaves under the low temperature stress, more seemingly in the weak cold resistance cultivars than in the stronger ones. Conclusions: It was obvious that there was a close relation between the cold resistance and the cell membrane permeability, MDA contents, SOD and POD activities and the contents of proline, soluble sugar and soluble protein in different cassava cultivars. And those physiological characters could be used as indexes of cold resistance.
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