Effects of salicylic acid on seed germination and physiological characters of cauliflower seedlings under salt stress

Effects of salicylic acid on salt stress-induced injuries were investigated during the stage of seed germination and seedling growth of cauliflower(Brassica oleracea var.botrytis).Under the stress,presoaking the seeds with 0.5-1.5 mmol/L of salicylic acid increased the germination percentage,germination energy,germination index and relative α-amylase activity of cauliflower.Among the treatment of salicylic acid,1.0 mmol/L had the best effect.The results also showed that treatment with 0.5-1.5 mmol/L of salicylic acid during the stage of seedling growth under salt stress increased the plant height,stem diameter,leaf area,chlorophyll contents,free proline and water dissolved-carbohydrate contents,the activities of superoxide dismutase(SOD) and peroxidase(POD),and decreased the content of malondialdehyde(MDA),suggesting that the exogenous SA(salicylic acid) could effectively mitigate the injuries of salt stress and increase salt-tolerance of cauliflower seeds and seedlings by increasing α-amylase activity,osmotic regulation and antioxidation.The best treatment concentration of salicylic acid was 1.0 mmol/L.When the concentration of SA was beyond 2.0 mmol/L,no mitigation effect was observed on the seeds germination and growth of seedling under salt stress.