喷施亚精胺缓解宽叶香蒲镉毒害的研究

Toxic Influences of Cd2+ on Typha latifolia L. Mitigated by Spermidine

采用培养箱培养方法,研究了喷施不同浓度植物生长素Spd,对不同浓度Cd2+胁迫下宽叶香蒲叶片和地下茎中活性氧、脂质过氧化,抗氧化系统生理指标的影响。结果表明,单一镉处理可以诱导宽叶香蒲叶片和地下茎O·2-产生速率、H2O2、MDA和GSH含量的增加;外源Spd促进叶片和地下茎中GSH含量的上升,抑制活性氧和MDA的产生,且0.25mmol·L-1Spd比0.5mmol·L-1Spd处理更有效地降低了MDA含量。镉胁迫不同程度地提高了叶片和地下茎CAT、GPX、GR和茎部SOD的活性,而使SOD活性下降;叶片喷施Spd可进一步提高叶片和地下茎中GR活性以及地下茎的SOD、CAT、GPX活性,但不能缓解镉胁迫下叶片SOD活性的下降,叶片CAT的活性变化随Spd和Cd2+浓度的不同而各异。推测:外源Spd可能主要通过提高GR活性和抗氧化剂(GSH和内源多胺)的含量来提高宽叶香蒲对镉胁迫的抗性。

In order to understand the mechanism polyamines （PAs） ameliorating the damage to plants by heavy metal and improving the phy toremediation efficiency of heavy metal-contaminated water, the effects of different concentrations of Spd （0.25～0.50 mol·L^-1） on the antioxidant system under Cd^2＋ stress （0.1～0.2 mol·L^-1） in T. latifolia were investigated. The results showed that Cd^2＋ stress induced an increase in the generation of O2^-, as well as the H2O2, MDA and GSH contents in both leaves and caudices. The contents of AOS were decreased by exogenous Spd and the decrease in MDA was more obvious at 0.25 mol·L^-1 of Spd than that at 0.50 mol·L^-1, while the GSH content in both leaves and caudices was obviously prompted by the application of exogenous Spd. With the exception of SOD activity in the leaves, an increase in the activities of CAT, GPX and GR was observed in both leaves and caudices, SOD activity was increased in caudices under Cd^2＋ treatments. Spraying with Spd increased the activity of GR in both leaves and caudices, whereas the activity of SOD, CAT and GPX was increased only in caudices. The SOD activity in leaves decreased with the application of Spd, and changes of CAT activity in leaves depended on the contents of Cd^2＋ and Spd. It is suggested that exogenous Spd elevated the tolerance of T. latifolia to Cd^2＋ stress primarily through increasing GR activity and the GSH level.