外源H2O2对NaCl胁迫下番茄幼苗生长及生理指标的影响

Effect of exogenous hydrogen peroxide on the growth and physiological indexes of tomato seedlings under NaCl stress

采用水培法研究外源过氧化氢(H2O2)对NaCl胁迫下番茄幼苗内源H2O2水平、生长及抗逆生理指标的影响。结果表明:NaCl胁迫导致H2O2积累、氧化胁迫加剧,显著抑制了番茄幼苗的生长;而外源喷施0.01 mmol/L H2O2和5 mmol/L DMTU均能提高脯氨酸含量,增强抗氧化酶SOD、POD和CAT活性,降低内源H2O2水平、电解质渗出率和MDA含量,从而缓解NaCl胁迫对番茄幼苗生长的抑制作用;NaCl胁迫下番茄幼苗叶片施用H2O2处理所产生的内源H2O2水平高于施用DMTU处理的,这与外源喷施H2O2缓解盐胁迫的效果优于喷施DMTU的结果一致,表明外源H2O2可通过诱导渗透调节能力及清除活性氧的防御能力、维持一定的内源H2O2水平、降低细胞膜脂过氧化程度、保护膜结构的完整性,从而有效缓解NaCl胁迫对番茄幼苗生长的抑制,提高其耐盐性。

A hydroponic experiment was performed to investigate the effects of exogenous hydrogen peroxide(H2O2)on the endogenous H2O2 levels,growth and stress resistance physiological indexes of tomato seedlings under NaCl stress.The results showed that NaCl stress increased the accumulation of H2O2 and increased oxidative stress,which significantly inhibited the growth of tomato seedlings.However,the exogenous application of 0.01 mmol/L H2O2 and 5 mmol/L DMTU could increase the content of proline and the activities of antioxidant enzymes SOD,POD and CAT,decrease endogenous H2O2 levels,electrolyte exudation rate and MDA content,thereby alleviating the inhibitory effect of NaCl stress on tomato seedling growth.In addition,under NaCl stress,the endogenous H 2O 2 content produced by H2O2 treatment in tomato seedling leaves was higher than that treated with DMTU,which is in consistent with the ability of exogenous H2O2 torelieve salt stress was better than that of DMTU.These results indicate that exogenous H2O2 could effectively alleviate the inhibition of NaCl stress on tomato seedling growth and improve its salt tolerance by inducing osmotic regulation and the defensive ability of reactive oxygen species scavenger system,maintaining a certain level of endogenous H2O2,reducing the degree of lipid peroxidation of cell membrane and protecting the integrity of membrane structure.