冷锻炼对提高水稻幼苗抗寒性及其细胞器膜结构稳定性的影响

Effects of Cold Hardening on Cold-resistance and Stability of Organel-la Membrance System in Rice Seedling (Oryza sativa L. )

冷锻锻炼对不同水稻品种抗寒力的增强作用有明显差异.抗寒品种冷锻炼后,超氧物歧化酶(SOD)活性提高,细胞质膜电导率下降,这一状态能在5 d低温处理(5℃,4000 lx/12 h)中保持;而冷敏品种冷锻炼后,SOD活性只能在最初的2d内保持,并随低温处理时间延长而丧失,其电导率、丙二醛(MDA)、脯氨酸以及细胞器膜系统超微结构,都表现了类似的变化趋势.由此认为,冷锻炼对增强冷敏品种抗寒力的作用较小而短暂,提高水稻抗寒性的根本措施应是改造和提高抗寒的遗传基础.

Rice seedlings via cold hardening with a day/night temperature variation of 15℃/10℃ for 2 d and continually cold stress 5℃ for 5 d were employed to investigate the changes of plans-mamembrance conductivity, superoxidase (SOD) activity, the contents of proline and the level of lipid peroxidation products (MDA). The results indicated that the cold hardening enhanced the activities of SOD, lessened plasmamembrance conductivities, and kept the adaption of seedlings to cold stress in cold-tolerance rice cultivars. On the other hand, in cold-sensitive cultivars, the activitties of SOD enhanced by cold hardening kept only 2 d, and the same tendency was observ in the contents of proline and the level of MDA. Therefore, the effect of cold hardening on cold-tolerance is limited for the cold-sensitive rice seedling, and genetic improvement is essential to the cold-tolerence characteristics of rice.