外源亚精胺处理对自毒作用下黄瓜胚根生理生化特性的影响

Effect of exogenous spermidine treatment on physiological and biochemical characteristics of the cucumber radicles under autotoxicity

为了探明外源亚精胺(spermidine,Spd)对黄瓜自毒作用的缓解机制,以‘津研四号’黄瓜(Cucumis sativus)为试材,分别用0、10、25、50、75、100、125μmol·L-1的Spd溶液进行预处理,10 mmol·L-1的对羟基苯甲酸(ρ-hydroxybenzoic acid,PHBA)溶液对黄瓜种子模拟自毒作用。试验结果表明:用10、25、50、75、100μmol·L-1的Spd预处理黄瓜种子,均能不同程度缓解PHBA胁迫对胚根生长的抑制作用,其中50μmol·L-1的Spd缓解效果最好。50μmol·L-1的Spd显著缓解了PHBA胁迫对黄瓜种子中淀粉酶以及胚根中抗氧化酶和氮代谢酶活性的抑制作用,降低了胚根中O2ˉ的产生速率、H2O2及丙二醛(malondialdehyde,MDA)的含量,提高胚根细胞存活率。说明外源Spd可能是通过降低氧化胁迫和促进淀粉的分解转化降低自毒物质对黄瓜发芽过程中造成的胁迫。研究结果为缓解自毒作用造成的蔬菜连作障碍提供了新的方法,同时为Spd缓解PHBA胁迫方面提供了一定的理论基础。

In order to elucidate the mitigation mechanism of exogenous spermidine(Spd)on cucumber autotoxicity,’Jinyan No.4’cucumber was used as experimental materials.Spd solution of 0,10,25,50,75,100 and 125μmol·L-1 were used to pretreat cucumber seeds before 10 mmol·L-1 p-hydroxybenzoic acid(PHBA)was treated.The results showed that pretreatment of cucumber seeds with 10,25,50,75 and 100μmol·L-1 Spd could alleviate the inhibition of PHBA stress on radical growth in varying degrees,among which 50μmol·L-1Spd had the best alleviation effect.Spd of 50μmol·L-1 significantly alleviated the inhibition of PHBA stress on amylase in seeds,the antioxidant enzymes and nitrogen metabolic enzymes in cucumber radicles,decreased the production rate of O2ˉ,the content of H2O2 and MDA in radical,increased the survival rate of radical cells.It indicated that exogenous Spd could reduce the stress of autotoxic substances on cucumber germination by reducing oxidative stress and promoting starch decomposition and transformation.The results provide a new method to alleviate the vegetable succession cropping obstacle caused by autotoxicity,and provide a theoretical basis for Spd to alleviate PHBA stress.