Effect of Low Temperature on Physiological Index of Cold-tolerant Casuarina glauca Clones

Cold-tolerant clones of Casuarina glauca were established through vegetative reproduction of the plants survived under low temperature (-5—6 ℃) stress. The physiological characteristics of two cold-tolerant clones and the control at 4 low-temperature gradient treatments from -2 ℃ to -11 ℃ were tested. The results showed that the relative conductivity, soluble protein content, MDA content and SOD activity of all clones increased with the temperature decrease. The relative conductivity of two cold- tolerant C. glauca clones were lower than that of the control, while the soluble protein content, MDA content and SOD activity were higher than that of the control. The relative conductivity, the soluble protein content, MDA content and SOD activity can be used as screening index for the cold tolerance identification of C. glauca. The Ci 36 clone was stronger cold-tolerant than Ci 24 clone.