植物学报 ›› 2014, Vol. 49 ›› Issue (3): 262-272.DOI: 10.3724/SP.J.1259.2014.00262

• 研究报告 • 上一篇    下一篇

Ca2+和K+对拟南芥幼苗镉毒害的缓解作用

汪骢跃, 王宇涛, 曾琬淋, 李韶山*   

  1. 华南师范大学生命科学学院, 广东省高等学校生态与环境科学重点实验室, 广州 510631
  • 收稿日期:2014-01-07 修回日期:2014-03-03 出版日期:2014-05-01 发布日期:2014-06-03
  • 通讯作者: 李韶山
  • 基金资助:

    拟南芥STO基因参与UV-B信号转导的功能及机理研究;华南地区严重危害入侵植物五爪金龙的生态适应性及转录组学研究

Alleviation of Cd Toxicity in Arabidopsis thaliana Seedlings by Exogenous Ca2+ or K+

Congyue Wang, Yutao Wang, Wanlin Zeng, Shaoshan Li*   

  1. Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, School of Life Sciences, South China Normal University, Guangzhou 510631, China
  • Received:2014-01-07 Revised:2014-03-03 Online:2014-05-01 Published:2014-06-03
  • Contact: Shao-Shan LI

摘要: 该文探讨了外源钙(Ca)或钾(K)处理对不同程度的镉(Cd)胁迫(0–80 μmol·L–1)下拟南芥(Arabidopsis thaliana)幼苗的生长和生理特性的影响。综合Ca和K对不同浓度Cd胁迫下拟南芥幼苗生长、根长以及生物量的影响情况, 表明各浓度Cd胁迫下外源Ca2+的最适缓解浓度均为10 mmol·L–1; 而K+的最适缓解浓度在低浓度(20和40 μmol·L–1)和高浓度(60和80 μmol·L–1)Cd胁迫下分别为10 mmol·L–1和20 mmol·L–1。在低浓度Cd胁迫下, 添加适宜浓度的Ca2+或K+后幼苗可溶性蛋白和丙二醛(MDA)含量以及超氧化物歧化酶(SOD)活性相比未添加Ca和K的对照组无显著变化, 而过氧化物酶(POD)活性和总酚、类黄酮、花色素苷, 酸溶性硫醇化合物、谷胱甘肽(GSH)、植物螯合肽(PCs)的含量均下降; 高浓度Cd处理下, 添加适宜浓度的Ca2+或K+后幼苗的SOD活性升高, POD活性降低, 可溶性蛋白、MDA、总酚、类黄酮、花色素苷、酸溶性硫醇化合物、GSH以及PCs的含量也均低于对照组。在各浓度Cd胁迫下, 添加外源Ca或K均使拟南芥幼苗根部细胞DNA损伤减弱, 表现为TT嘧啶二聚体的累积量显著减少(P<0.05)。以上结果表明, 在Cd胁迫(尤其是高浓度Cd胁迫)下, 外源Ca或K通过调节酚类、金属螯合物质的代谢水平以及提高拟南芥的抗氧化能力来缓解Cd对拟南芥幼苗的毒害效应, 缓解细胞DNA损伤。该研究结果不仅能够为深入探讨Ca和K对缓解重金属毒害的分子机理提供实验依据, 而且为Ca和K应用于重金属污染的防治提供参考。

Abstract: We investigated the effect of exogenous Ca or K on the growth and physiological parameters of Arabidopsis thaliana seedlings under different levels of Cd stress (0, 20, 40, 60 and 80 μmol·L–1). The optimal alleviation concentration for Ca2+ was 10 mmol·L–1 under all levels of Cd stress in terms of root growth and biomass of seedlings. The optimal alleviation concentration for K+ was 10 mmol·L–1 under low Cd stress (20 and 40 μmol·L–1) and 20 mmol·L–1 under high Cd stress (60 and 80 μmol·L–1). Under low Cd treatment, the exogenous addition of Ca or K with the optimal concentration resulted in recovered root growth and increased biomass, with no change in superoxide dismutase (SOD) activity, soluble protein content or malony dialdehyde (MDA) content of seedlings. The addition of Ca or K significantly decreased peroxidase (POD) activity and decreased total phenol, flavonoid, anthocyanin, total acid thiol, glutathione (GSH) and phytochelatins (PCs). Under high Cd stress, the exogenous addition of the optimal concentration of Ca2+ or K+ increased SOD activity and decreased POD activity. The addition of Ca or K significantly decreased levels of soluble protein, MDA, total phenol, flavonoid, anthocyanin, total acid thiol, GSH and PCs. Under all levels of Cd, the TT pyrimidine dimer contents were higher in the seedlings without than with Ca and K (P<0.05), so the DNA damage in seedlings was alleviated by the addition of Ca or K. Exogenous addition of Ca or K can alleviate the toxicity of Cd in Arabidopsis seedlings, especially under high Cd stress, by mediating the metabolic levels of antioxidants, osmotic adjust substance, phenols and metal chelating substances, thus reducing DNA damage in cells. This study provides experimental data for the molecular mechanisms involving the alleviation effects of Ca and K on heavy metals and valuable references for the application of Ca and K in the remediation of heavy metal pollution.