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浙江大学学报（农业与生命科学版）
浙江大学学报(农业与生命科学版)  2014, Vol. 40 Issue (5): 559-567    DOI: 10.3785/j.issn.1008-9209.2013.11.171
资源与环境科学     
镉对旱柳幼苗生长及低相对分子质量巯基化合物含量的影响
杨卫东, 李廷强, 丁哲利, 杨肖娥*
(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)
Effects of Cd on growth and low molecular mass thiols of Salix matsudana Koidz seedlings
Yang Weidong, Li Tingqiang, Ding Zheli, Yang Xiaoe*
(Key Laboratory of Environmental Remediation and Ecosystem Health of the Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University,  Hangzhou 310058, China
)
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摘要： 通过溶液培养方法,研究
在镉(Cd)处理下旱柳生长、Cd积累、耐性及低相对分子质量巯基化合物对Cd胁迫的响应。结果表明：与对照相比,在Cd浓度≥25 μmol/L时显著降低相对生长速率;地上部、根以及整株生物量随着介质Cd浓度升高而逐渐降低,在Cd浓度≥5 μmol/L时显著降低了根生物量,而Cd浓度≥25 μmol/L时显著降低地上部生物量;同时,随着Cd浓度增加耐性指数也逐渐降低;用根表示半数抑制浓度(50% effective concentration,EC50)为82 μmol/L;根和地上部含Cd量随着介质Cd浓度升高而增加,Cd主要积累于根部,在5~25 μmol/L时,地上部含Cd量为64.89~163.13 μg/g,此时植物生长没有受到严重影响;根和叶非蛋白质巯基(non-protein thiols,NPTs)、蛋白质巯基(protein thiols,PTs)和总巯基(total thiols,TTs)化合物含量随着介质Cd浓度增加而增加;中高Cd浓度使根部半胱氨酸(cysteine,Cys)含量高于对照,在Cd浓度范围为 5~50 μmol/L时叶部Cys含量没有显著影响,而Cd浓度为100 μmol/L时降低了叶中Cys含量;与对照相比,Cd提高了根中还原型谷胱甘肽(reduced glutathione,GSH)含量,而对叶中GSH含量没有影响,根和叶氧化型谷胱甘肽(oxidized glutathione,GSSG)含量降低,GSH/GSSG值高于对照。这些结果表明低相对分子质量巯基化合物在Cd忍耐与解毒中起重要作用。
Abstract: Contamination of soil and water with cadmium (Cd) is a widespread and serious environmental problem. Cd is a non-essential element which is the most toxic when dispersed in the environment. Plants have evolved many mechanisms to tolerate and detoxify metals to reduce their cellular toxicity, and plants can produce low molecular mass thiol compounds that involve in tolerance and detoxification to toxic metals. Currently, willows (Salix spp.) with large biomass are high-metal accumulators which have been widely used in phytoextraction of heavy metals such as Cd. However, compared to the hyperaccumulators and some herbaceous plants, it remains unknown that willows can tolerate and detoxify Cd. Salix matsudana Koidz is an economically pioneer tree which is native to China, commonly planted on riverbanks and flooding plains. The objectives of this study were: 1) To investigate Cd tolerance and uptake in S. matsudana; 2) To evaluate thiol compounds in responses to Cd. Seedlings of S. matsudana were grown in hydroponic culture exposed to various Cd levels (0, 5, 25, 50, and 100 μmol/L) in a greenhouse for 28 d. The growth parameters were measured including relative growth rate (RGR) and biomass production. The EC50 (50% effective concentration, EC50) based on root, shoot (including stem and leaf) and whole plant biomass was calculated, respectively. Thiol compounds were assayed, i.e., non-protein thiols (NPTs), protein thiols (PTs), total thiols (TTs), cysteine (Cys), reduced glutathione (GSH) and oxidized glutathione (GSSG). The results showed that RGR of height significantly decreased at Cd≥25 μmol/L. Biomasses of shoot, root and whole plant decreased with increasing Cd concentrations in the medium. Root biomass was significantly reduced at Cd≥5 μmol/L, while shoot biomass was reduced at Cd≥25 μmol/L compared with  the control. Tolerance indexes (based on root, shoot and whole plant, respectively) were decreased with increasing Cd concentrations in the medium. EC50 based on root biomass reached 82 μmol/L. Cd concentrations in shoots and roots were elevated with increasing Cd concentrations in the medium, and Cd accumulated mainly in roots. Cd concentration in shoots ranged from 64.81 to 163.13 μg/g exposed to 525 μmol/L Cd, and plant growth was not severe disturbed. The contents of NPTs, PTs and TTs in roots and leaves were induced strongly by Cd exposure, and their contents increased with increasing Cd concentrations in the medium. Compared with the control, high Cd (100 μmol/L) enhanced an increase in Cys content in roots; in contrast, Cys contents in leaves were not markedly altered at 550 μmol/L Cd, but reduced significantly at 100 μmol/L Cd. GSH contents increased in roots but showed no significant alteration in leaves; GSSG contents of roots and leaves were reduced, and GSH/GSSG ratios were increased compared with the control. In conclusion, the present results show that the plants are  not able to cope with Cd stress displaying phytotoxic effects exposed to high concentrations of Cd. Cd treatments induce markedly changes in thiol compounds, and the results further suggest  that the thiol-based mechanism may contribute to Cd tolerance and detoxification in S. matsudana.
出版日期: 2014-09-20
CLC:  Q 89  
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杨卫东
李廷强
丁哲利
杨肖娥*

引用本文:

杨卫东, 李廷强, 丁哲利, 杨肖娥*. 镉对旱柳幼苗生长及低相对分子质量巯基化合物含量的影响[J]. 浙江大学学报(农业与生命科学版), 2014, 40(5): 559-567.

Yang Weidong, Li Tingqiang, Ding Zheli, Yang Xiaoe*. Effects of Cd on growth and low molecular mass thiols of Salix matsudana Koidz seedlings. Journal of Zhejiang University (Agriculture and Life Sciences), 2014, 40(5): 559-567.

链接本文:

http://www.zjujournals.com/agr/CN/10.3785/j.issn.1008-9209.2013.11.171    或    http://www.zjujournals.com/agr/CN/Y2014/V40/I5/559

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