Use of micro-PIXE to determine spatial distributions of copper in Brassica carinata plants exposed to CuSO₄ or CuEDDS

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• 作者：Benedetta Cestone^a ; ^{benedettacestone@yahoo.it} ; Katarina Vogel-Miku&scaron ; ^b ; Mike Frank Quartacci^a ; Nicoletta Rascio^c ; Paula Pongrac^b ; Primo啪 Pelicon^d ; Primo啪 Vavpeti膷^d ; Nata&scaron ; a Grlj^d ; Luka Jeromel^d ; Peter Kump^d ; Marijan Ne膷emer^d ; Marjana Regvar^b ; Flavia Navari-Izzo^a
• 关键词：Brassica carinata ; Copper ; EDDS ; Spatial distribution ; XRF ; Micro-PIXE
• 刊名：Science of the Total Environment
• 出版年：2012
• 期刊代码：63_00489697
• 类别：env
• 出版时间：15 June, 2012
• 卷：427-428
• 期：Complete
• 页码：339-346
• 文件大小：2304 K

摘要

A better understanding of the mechanisms that govern copper (Cu) uptake, distribution and tolerance in Brassica carinata plants in the presence of chelators is needed before significant progress in chelate-assisted Cu phytoextraction can be made. The aims of this study were therefore to characterise (S,S)-N,N鈥?ethylenediamine disuccinic acid (EDDS)-assisted Cu uptake, and to compare the spatial distribution patterns of Cu in the roots and leaves of B. carinata plants. The plants were treated with 30 渭M or 150 渭M CuSO₄ or CuEDDS in hydroponic solution. Quantitative Cu distribution maps and concentration profiles across root and leaf cross-sections of the desorbed plants were obtained by micro-proton induced X-ray emission. In roots, the 30 渭M treatments with both CuSO₄ and CuEDDS resulted in higher Cu concentrations in epidermal/cortical regions. At 150 渭M CuSO₄, Cu was mainly accumulated in root vascular bundles, whereas with 150 渭M CuEDDS, Cu was detected in endodermis and the adjacent inner cortical cell layer. Under all treatments, except with a H⁺-ATP-ase inhibitor, the Cu in leaves was localised mainly in vascular tissues. The incubation of plants with 150 渭M CuEDDS enhanced metal translocation to shoots, in comparison to the corresponding CuSO₄ treatment. Inhibition of H⁺-ATPase activity resulted in reduced Cu accumulation in 30 渭M CuEDDS-treated roots and 150 渭M CuEDDS-treated leaves, and induced changes in Cu distribution in the leaves. This indicates that active mechanisms are involved in retaining Cu in the leaf vascular tissues, which prevent its transport to photosynthetically active tissues. The physiological significance of EDDS-assisted Cu uptake is discussed.