水杨酸对盐胁迫下花椰菜种子萌发及幼苗生理特性的影响

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

以先华70和祁连白雪2个耐盐性不同的花椰菜品种为材料,在125mmol/L NaCl胁迫处理下,研究了不同浓度水杨酸对花椰菜种子萌发及幼苗生理特性的影响。结果表明,盐胁迫下,0.5～1.5mmol/L SA浸种预处理的花椰菜种子具有较高的发芽率、发芽势、发芽指数及ɑ-淀粉酶活性,其中以1.0mmol/L的SA处理效果最好;0.5～1.5mmol/L SA处理的花椰菜幼苗具有较高的株高、茎粗和较大的叶面积,其叶绿素含量、可溶性糖含量、脯氨酸含量以及超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性均较高,而丙二醛(MDA)含量较低,其中以1.0mmol/L SA处理效果最好。说明0.5～1.5mmol/L外源SA可以通过提高ɑ-淀粉酶活性,提高花椰菜幼苗渗透调节能力和抗氧化能力,诱导花椰菜种子萌发和幼苗的耐盐性,减轻和缓解盐害,SA浓度超过2.0mmol/L时对盐胁迫没有缓解效应。

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.