旱柳根系细胞壁多糖和抗氧化系统对镉的响应  

Responses of Root Cell Wall Polysaccharides and Antioxidant System of Salix matsudana Koidz to Cadmium

作　　者：曾小仪 庞璐[1] 陈韵如 田兴军[1] ZENG Xiao-yi;PANG Lu;CHEN Yun-ru;TIAN Xing-jun(School of Life Sciences,Nanjing University,Jiangsu Nanjing 210023,China)

机构地区：[1]南京大学生命科学学院,江苏南京210023

出　　处：《西南农业学报》2020年第11期2635-2642,共8页Southwest China Journal of Agricultural Sciences

基　　金：江苏省水利科技项目(ZQ2018107);江苏省林业三新工程项目(LYSX[2016]46);国家自然科学基金面上项目(31870598);国家重大研究项目(2016YFD0600204)。

摘　　要：【目的】研究旱柳(Salix matsudana Koidz)根系细胞壁多糖对根系富集镉(Cd)的重要作用以及抗氧化系统表征的耐受性对Cd的响应,为植物富集技术的发展提供理论支撑。【方法】旱柳插条分别在含有Cd浓度为0μmol/L(CK)、25μmol/L(Cd25,低浓度Cd)和75μmol/L(Cd75,高浓度Cd)的营养液中培养。测定生长指标、Cd含量、细胞壁多糖含量和氧化应激指标。【结果】高浓度Cd会显著减少旱柳的生物量、茎长和根长。根系是旱柳积累Cd的主要部位,其积累Cd的能力与根系细胞壁多糖的含量和结构密切相关。Cd25和Cd75处理的果胶含量和果胶甲酯酶活性显著高于对照。Cd25处理的半纤维素2的含量以及Cd75处理的半纤维素1的含量显著高于对照。此外,Cd诱导旱柳活性氧和丙二醛过度产生,高浓度Cd显著抑制过氧化氢酶和过氧化物酶的活性以及叶片还原型谷胱甘肽的含量。【结论】Cd处理使根系细胞壁中果胶、低甲酯化果胶和半纤维含量升高,意味可结合Cd的负电基团数量增多。此外,旱柳不同部位的抗氧化系统对Cd胁迫的响应存在一定的差异。未来植物修复的应用应充分考虑细胞壁多糖的作用以及植物不同部位对金属的耐受性差异。【Objective】The present paper aimed to study the importance of cell wall polysaccharides to cadmium(Cd)enrichment and the response of antioxidant system to Cd of Salix matsudana,in order to provide theoretical support for the application of phytoremediation.【Method】S.matsudana cuttings were cultured in nutrient solution containing concentrations of Cd 0μmol/L(CK),25μmol/L(Cd25,low concentration of Cd),and 75μmol/L(Cd75,high concentration of Cd),respectively.Plant growth,Cd content,root cell wall polysaccharide contents and oxidative stress were then measured.【Result】High concentration of Cd reduced plant biomass,stem and root lengths.Root was the main part of S.matsudana on Cd accumulation,and its Cd accumulation capacity was closely related to the content and structure of cell wall polysaccharides.Pectin contents and pectin methylesterase activity in Cd25 and Cd75 treatments were higher than those in the control.Hemicellulose 2 content in Cd25 treatment and hemicellulose 1 content in Cd75 treatment were significantly higher than those in the control.In addition,Cd induced excessive production of reactive oxygen species and malondialdehyde,and high concentration of Cd inhibited catalase and guaiacol peroxidase activity and leave glutathione content.【Conclusion】Cd increased the contents of pectin,low methyl-esterification pectin,and hemicellulose,which means there were more negative groups in the cell walls to bind Cd.In addition,the damage of Cd against oxidation system is different in plant parts.The application of phytoremediation in the future should fully consider the importance of cell wall polysaccharides and the tolerance differences of plants parts to metals.

关 键 词：植物修复 果胶 半纤维素 果胶甲酯酶 氧化应激 

分 类 号：S687[农业科学—观赏园艺]