Inducing effects of exogenous ABA on seed germination and cold tolerance of winter rape seedlings

In order to investigate the inducing effects of cold tolerance of winter rapeseed by exogenous ABA in northern drought and cold region,two winter rapeseed cultivars Longyou 6( cold resistant) and Tianyou 2( cold susceptible) were presoaked with different concentrations of ABA. The effect of different ABA concentrations on seed germination and related cold resistance indexes of winter rapeseed were studied under normal temperature and cold stress. The results showed that the concentration of 10 ~ 70 mg·L- 1promoted seed germination,while that of80 mg·L- 1abscisic acid solution lowed germination ability and percentage. The recommended concentration of abscisic acid is 30 mg·L- 1,increasing superoxide dismutase( SOD),peroxidase( POD) and catalase( CAT) activities,alleviating the chlorophyll degradation,and elevating proline content but decreasing MDA content,the product of membrane lipid peroxidation. In addition,the effects of exogenous ABA on winter rapeseed varied with varieties,and it was obvious for Longyou 6 with high chilling resistance.