低温锻炼对草莓组培苗抗寒性及抗氧化酶活性的影响

Effects of Cold-hardening on Freezing Tolerance and Antioxidant Enzyme Activities in Plantlets of Strawberry

草莓组织培养苗经4℃低温锻炼后抗寒性明显增强,SOD、CAT、POD和APX活性明显提高,可溶性蛋白质、脯氨酸和可溶性糖等渗透调节物质含量增加。同时,低温锻炼对膜造成了一定程度的伤害,表现为MDA含量的增加。脱锻炼后抗氧化酶活性和可溶性蛋白质、脯氨酸、可溶性糖及MDA含量略有下降,但仍高于未锻炼植株。这些变化是草莓组织培养苗适应低温逆境的生理生化基础。

To elucidate the freezing tolerance mechanism of perennial plants, Strawberry was used as model plant. Activities of antioxidant enzyme and solute contents were investigated in planflets of Strawberry. Coldhardening （4℃） increased the activities of SOD, CAT, POD and APX in planflets. A similar increase was also observed in the protein, proline and soluble carbohydrates content. Meanwhile, low-temperature increased the MDA content. These results obtained suggest that the higher activities of SOD, CAT, POD and APX as well as the higher protein, proline, soluble carbohydrates and MDA content may be biochemical adaptation for freezing tolerance in cold-hardened Strawberry planflets. Interestingly, deacclimation was slow; even after the plants were placed again under a temperature of （25±1）℃ for 3d. The higher freezing hardiness, enzyme activities, protein, proline and soluble carbohydrates content acquired after cold acclimation remained. In conclusion, our plantlet cultures have proved to be good materials for experimentation on freezing resistance in study of freezing-resistance mechanism in Strawberry.