Cadmium tolerance in Brassica juncea roots and shoots is affected by antioxidant status and phytochelatin biosynthesis
Cadmium tolerance in Brassica juncea roots and shoots is affected by antioxidant status and phytochelatin biosynthesis
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DOI：
10.1016/j.plaphy.2012.05.002
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发表时间：
2012-08-01
影响因子：
6.5
通讯作者：
Sanita di Toppi, Luigi
中科院分区：
文献类型：
--
作者：
Mohamed, Amal Amin;Castagna, Antonella;Sanita di Toppi, Luigi
印度芥菜 (Brassica juncea L Czern.) 能耐受高浓度的重金属，是从金属污染土壤中植物提取镉 (Cd) 的有前途的物种。这项工作研究了抗氧化剂和金属螯合机制在多大程度上导致了这种耐受性。为此，将印度芥菜幼苗在0、50或200μM Cd中培养7天。镉浓度的增加导致根和芽中镉的逐渐积累，伴随着矿物质吸收的器官依赖性改变，以及根/芽长度和鲜重/干重的减少。镉对叶绿素和类胡萝卜素含量产生负面影响，并激活叶黄素循环，表明需要保护光合装置免受光抑制。过氧化物酶和过氧化氢酶活性以及抗坏血酸水平（仅与最高镉浓度有关）对镉胁迫的不同反应表明，芽在ROS清除方面的效率似乎低于根。这种不同的抗氧化能力至少可以部分解释在两个器官中观察到的脂质过氧化趋势的差异。此外，无论涉及的金属浓度如何，根和芽中的谷胱甘肽和植物螯合素含量在镉胁迫下均显着增加。 (C) 2012 Elsevier Masson SAS。版权所有。
Indian mustard (Brassica juncea L Czern.) tolerates high concentrations of heavy metals and is a promising species for the purpose of phytoextraction of cadmium (Cd) from metal-contaminated soils. This work investigates the extent to which antioxidant and metal sequestering mechanisms are responsible for this tolerance. To this end, seedlings of Indian mustard were grown for 7 days in 0, 50 or 200 mu M Cd. Increasing Cd concentrations led to a progressive Cd accumulation in roots and shoots, accompanied by an organ-dependent alteration in mineral uptake, and a decrease in root/shoot length and fresh/dry weight. Cd negatively affected chlorophyll and carotenoid contents and activated the xanthophyll cycle, suggesting the need to protect the photosynthetic apparatus from photoinhibition. Shoots seemed to be less efficient than roots in ROS scavenging, as indicated by the different response to Cd stress shown by peroxidase and catalase activities and, solely with regard to the highest Cd concentration, by ascorbate level. Such a different antioxidant capacity might at least partly explain differences in the trend of lipid peroxidation observed in the two organs. Moreover, in both roots and shoots, glutathione and phytochelatin content markedly increased under Cd stress, regardless of the metal concentration involved. (C) 2012 Elsevier Masson SAS. All rights reserved.