A DIFFERENCE IN COLD TOLERANCE AMONG LITCHI CULTIVARS AND ITS MECHANISM

The leaf cell structure and several physiological characteristics of 14 litchi (Litchi chinensis) cultivars were analyzed in this paper. The result showed that the cultivar with large leaf cell tissue ratio had strong cold resistance, reversely the cold resistance of cultivar with low leaf cell tissue ration was weak, therefore leaf cell tissue ratio may be taken as an index to detect cold tolerance of litchi; the contents of free proline, soluble sugar, and soluble protein, and the activity of superoxide dismutase (SOD) that were positively correlated with the leaf cell tissue ratio, can reflect differences in cold tolerance among various litchi cultivars, therefore, they could effectively be used as methods to determine the cold resistance of cultivars.