Effects of Abscisic Acid on Chilling Tolerance of Strawberry Seedlings

The strawberry was used as experimental material and its roots were soaked or leaves drenched withdifferent concentrations of abscisic acid(ABA). The physiological and biochemical indexes were determined to dis-cuss effect of ABA on chilling tolerance of strawberry seedlings. The results showed that respiration rate, root activi-ty, superoxide dismutase(SOD), peroxidase(POD) and catalase(CAT) of strawberry seedlings increased by ABAtreatment. The contents of chlorophyll, soluble sugar, soluble protein, proline(Pro) contents were higher than thecontrol, whereas malondialdehyde(MDA) content and electrical conductivity were lower than the control. When theABA concentration was 150ug·L-1, the strawberry seedlings' respiration rate, root activity, SOD, POD and CAT ac-tivity reached the highest, and chlorophyll, soluble sugar, soluble protein, proline(Pro) contents reached maximum,but malondialdehyde(MDA) content and conductivity reached minimum. Comparison of two methods, root soakingtreatment improved low temperature stress tolerance of root activity of seedling. Foliar treatment improved low tem-perature stress tolerance of the respiration rate and chlorophyll content of seedling. The others showed no significantdifference.