旱柳幼苗抗坏血酸-谷胱甘肽循环及谷胱甘肽代谢对镉胁迫的响应  

Responses of ascorbate-glutathione cycle and glutathione metabolism to cadmium stress in Salix matsudana Koidz seedlings

作　　者：杨卫东[1] 李廷强[1] 丁哲利[1] 杨肖娥[1] 

机构地区：[1]浙江大学环境与资源学院,污染环境修复与生态健康教育部重点实验室,杭州310058

出　　处：《浙江大学学报（农业与生命科学版）》2014年第5期551-558,共8页Journal of Zhejiang University:Agriculture and Life Sciences

基　　金：科技部国际合作项目(2010DFB33960);国家科技支撑计划项目(2012BAC17B02);国家自然科学基金资助项目(31100513)

摘　　要：采用营养液培养方法,研究旱柳(Salix matsudana Koidz)抗坏血酸-谷胱甘肽(ascorbate-glutathione,AsA-GSH)循环及谷胱甘肽代谢对镉(Cd)胁迫的响应.结果表明:Cd显著降低了根部抗坏血酸(ascorbate,AsA)含量,增进了叶部AsA积累,根脱氢抗坏血酸(dehydroascorbate,DHA)含量在低Cd时升高,根和叶DHA含量在高Cd时降低;高Cd时根和叶AsA/DHA值大于对照;根部还原型谷胱甘肽(reduced glutathione,GSH)含量在低Cd时增加,高Cd时降低,不同浓度Cd均提高了叶部GSH含量,而根与叶部氧化型谷胱甘肽(oxidized glutathione,GSSG)含量不同程度低于对照,根和叶GSH/GSSG值高于对照;根抗坏血酸过氧化物酶(ascorbate peroxidase,APX)活性在低Cd时轻微增加,高Cd时受到抑制,叶部APX活性不同程度增强;Cd不同程度提高了根与叶单脱氢抗坏血酸还原酶(monodehydroascorbate reductase,MDHAR)和脱氢抗坏血酸还原酶(dehydroascorbate reductase,DHAR)活性,仅在低Cd时根谷胱甘肽还原酶(glutathione reductase,GR)活性显著升高,不同浓度Cd使叶GR活性高于对照;Cd也使根和叶谷胱甘肽过氧化物酶(glutathione peroxidase,GPX)和谷胱甘肽转硫酶(glutathione S-transferase,GST)活性不同程度增加.这些结果表明旱柳通过调节AsA-GSH循环和谷胱甘肽代谢来实现对Cd的耐性与解毒.Summary Cadmium （Cd） is released into environment due to anthropogenic activities, resulting in great environmental problems.As a no-essential element,Cd displays high toxic to plants,resulting in leaf chlorosis, root necrosis,inhibition of photosynthesis,and disorder of water and nutrient metabolism.Simultaneously,Cd stress induces the generation of reactive oxygen species （ROS）.Plants have evolved many strategies to avoid Cd stress.The ascorbate-glutathione （AsA-GSH） cycle and glutathione metabolism involve in scavenging of ROS to prevent the accumulation of the strong oxidant H2 O2 . The AsA-GSH cycle contains four non-enzymatic antioxidants and four different enzymes,i.e.,ascorbate（AsA）,dehydroascorbate（DHA）and reduced glutathione＆amp;nbsp;（GSH）,oxidized glutathione（GSSG）,ascorbate peroxidase（APX）,monodehydroascorbate reductase（MDHAR）, dehydroascorbate reductase （DHAR） and glutathione reductase （GR）.AsA-GSH cycle plays a pivotal role in counteracting Cd toxicity.Glutathione metabolism coupled with glutathione peroxidase （GPX） and glutathione S-transferase （GST） also plays a key role in Cd tolerance and detoxification. In the last decade,willows （Salix spp.） have showed large phytoremediation potential for heavy metals,and were considered as high Cd accumulators than other plants.Salix matsudana Koidz is mainly distributed in China, which is widely planted in flood-prone lands,showing great potential in phytoremediation of Cd.But compared with hyperaccumulators and other herbaceous plants,the tolerance and detoxification of Cd in willows have been poorly understood.In the present study,we aimed to investigate the AsA-GSH cycle and GSH metabolism of S. matsudana in response to Cd stress. 〈br〉 Seedlings of S.matsudanas were mounted on Styrofoam and were grown in a hydroponic culture.After pre-gown for 60 days,seedlings with uniform size were selected and treated with different Cd doses（0,5 and 25μmol/L） for 28 d.Antioxidants （AsA,DHA,GSH,and

关 键 词：旱柳 镉 抗坏血酸-谷胱甘肽循环 谷胱甘肽代谢 

分 类 号：Q89[生物学] Q945