Pb胁迫下外源GSH对马蔺体内Pb积累和非蛋白巯基化合物含量的影响

Effects of Exogenous Glutathione on Pb Accumulation and Non-protein Thiol Content in Iris Lactea var.chinensis Under Pb Stress

采用溶液培养研究Pb胁迫以及Pb胁迫下添加外源谷胱甘肽(GSH)和丁胱亚磺酰胺(BSO)对马蔺根和叶干质量、Pb含量以及非蛋白巯基总肽(NPT)、谷胱甘肽(GSH)和其他非蛋白巯基化合物(植物螯合肽(PC)、半胱氨酸(Cys))含量的影响。结果表明,300mg/L高浓度Pb胁迫下马蔺根系内Pb的大量积累显著抑制马蔺根系的生长,但同浓度Pb胁迫下添加100mg/L GSH后马蔺体内Pb含量和干质量均不同程度增加,尤其是地上部,地上部干质量比300mg/L单独Pb胁迫下马蔺根系干质量增加20.5%,接近于对照水平。而300mg/L的Pb胁迫下添加100mg/L BSO(GSH和PC合成抑制剂)后马蔺根系和地上部干质量均不同程度下降,根系降幅较大。根和叶中非蛋白巯基化合物含量检测显示,与单独Pb胁迫相比,Pb胁迫下添加GSH后马蔺根系和地上部NPT、GSH和其他非蛋白巯基化合物含量均呈增加的趋势;而Pb胁迫下添加BSO后除马蔺地上部其他非蛋白巯基化合物含量略有增加外,马蔺根系和地上部NPT、GSH和其他非蛋白巯基化合物含量较单一Pb胁迫下均出现不同程度下降,尤其根系内GSH含量降幅最大。综合分析Pb胁迫下添加外源GSH和BSO后马蔺干质量、Pb含量以及不同非蛋白巯基化合物含量的变化及关系,表明Pb胁迫下添加BSO后马蔺生物量的下降可能与非蛋白巯基化合物合成受抑尤其是GSH的合成降低有关。因此,Pb胁迫下GSH在马蔺Pb吸收转运和解毒中具有更重要的作用。

The effects of lead(Pb)stress and adding exogenous glutathione(GSH)and L-buthione(S,R) sulfoximine(BSO)on dry biomass,Pb content and the contents of total non-protein thiol(NPT),GSH and other non-protein thiol such as phytochelatin(PC)and cysteine(Cys)in roots and leaves of Iris lactea var.chinensis were studied by hydroponic culture.The results showed that the massive accumulation of Pb significantly inhibited the growth of root in Iris lactea var.chinensis under 300mg/L high Pb stress,but Pb content and dry mass of Iris lactea var.chinensisincreased in degrees when adding 100mg/L GSH,especially the shoot dry biomass,which increased by 20.5%and closed to the level of the control compared to that of the single Pb stress.However,dry mass of Iris lactea var.chinensis decreased in degrees when adding 100mg/L BSO(GSH and PC synthesis inhibitor)to the same Pb solution,especially the dry biomass of underground.The detection of non-protein thiol content in roots and leaves showed that the contents of NPT,GSH and other non-protein thiol compounds in the shoots and roots all exhibited an increasing trend after adding GSH under Pb stress.But in addition to a slight increase in aboveground content of other non-protein thiol compounds in Iris lactea var.chinensis,the contents of NPT,GSH and other non-protein thiol compounds in the shoots and roots all decreased in degrees when adding 100mg/L BSO to the same Pb solution,especially the GSH contents in root declined sharply.The comprehensive analysis on the changes and relationship among dry mass,Pb content as well as different non-protein sulfhydryl content under single Pb stress and adding exogenous GSH and BSO to Pb solution indicated that the decline of biomass in Iris lactea var.chinensis might be related to being inhibited of non-protein thiol compound synthesis when adding BSO under Pb stress,especially GSH synthesis were obviously hindered.Therefore,GSH had a more important role in Pb absorption,transport and detoxification in Iris lactea var.chinensis.