孔雀草体内低分子质量巯基化合物对重金属镉的响应

Response of Low Molecular Mass Thiols to Heavy Metal Cadmium in Tagetes patula L.

[目的]探讨不同浓度镉胁迫对孔雀草不同组织中低分子质量巯基蛋白含量的影响。[方法]采用土培实验,研究不同镉浓度(0,100,300,500mg/kg)对孔雀草根、茎、叶中非蛋白巯基(NPT)、还原性谷胱甘肽(GSH)、氧化性谷胱甘肽(GSSG)、植物螯合肽(PCs)、半胱氨酸(Cys)含量的影响。[结果]随镉浓度升高,根、茎、叶中的NPT含量及PCs含量均呈先升后降趋势,而Cys、GSH、GSSG只在茎中呈先升后降趋势,根中的GSH和GSSG随镉浓度增加而增加,Cys含量则随镉浓度增加呈先降后升趋势,叶中Cys随镉浓度增加呈先降后升再降趋势,GSH随镉浓度增加呈先降后升趋势,GSSG则是先升后降趋势,GSH/GSSG值在根中最高,茎次之,Cd对叶GSH/GSSG值影响较小。[结论]低相对分子质量巯基化合物在孔雀草镉解毒过程中起重要作用。

[Objective]The present paper aims to explore the effects of different concentrations of Cd stress on the low molecular mass thiols in different tissues of Tagetes patula L.[Method]The effects of different concentrations of Cd(0,100,300,500 mg/kg)on the content of non-protein thiols(NPT),reduced glutathione(GSH),oxidized glutathione(GSSG),phytochelatin(PCs)and cysteine(Cys)in the root,stem and leaf of Tagetes patula L.were studied by soil culture experiment.[Result]the content of NPT and PCs increased first and then decreased in roots,stems and leaves with the increase of cadmium concentration.However,the content of Cys、GSH、GSSG only increased first and then decreased only in the stems,and the GSH and GSSG in the root increase with the increase of cadmium concentration,the content of Cys decreased first and then increased with the increase of cadmium concentration.And the content of Cys in leaves decreased first and then decreased with the increase of cadmium concentration.The GSSG increased first and then decreased with the increase of cadmium concentration but the GSH is the opposite.The content of GSH/GSSG ratios was the highest in root,followed by stems.Cd concentration had less effect on GSH/GSSG ratios in leaves[Conclusion]Low molecular mass thiol compounds play an important role in the process of cadmium detoxification in Tagetes patula L.