Arsenic distribution and speciation in the fronds of the hyperaccumulator Pteris vittata
Arsenic distribution and speciation in the fronds of the hyperaccumulator Pteris vittata
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DOI：
10.1046/j.1469-8137.2002.00512.x
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发表时间：
2002-11-01
期刊：
影响因子：
9.4
通讯作者：
McGrath, SP
中科院分区：
文献类型：
--
作者：
Lombi, E;Zhao, FJ;McGrath, SP
本文采用化学分析和能谱分析（EDXA）方法研究了砷在植物叶片和细胞水平上的分布。用X射线吸收近边光谱（XANES）分析了砷在叶中的形态分布，发现大部分砷存在于针叶中（占总砷的96%）。砷在针叶中的含量从叶基部到叶尖逐渐降低。孢子和中脉中的砷浓度远低于松叶甲。EDXA分析表明，As主要分布在上表皮细胞和下表皮细胞中，可能分布在液泡中。钾的分布模式与As相似，而其它元素（Ca、Cl、K、Mg、P和S）的分布模式不同，XANES分析表明，叶片中约75%的As以As（III）氧化态存在，其余为As（V）。
Pteris vittata is the first plant reported to be a hyperaccumulator of arsenic (As), and little is known about the mechanisms of As hyperaccumulation in this plant.Arsenic distribution at the whole plant (fronds) and cellular level was investigated using chemical analyses and energy dispersive X-ray microanalyses (EDXA). Speciation of As in the fronds was determined using X-ray absorption near edge spectroscopy (XANES) analyses.The majority of As was found in the pinnae (96% of total As). The concentration of As in pinnae decreased from the base to the apex of the fronds. Arsenic concentrations in spores and midribs were much lower than in the pinnae. EDXA analyses revealed that As was compartmentalized mainly in the upper and lower epidermal cells, probably in the vacuoles. The distribution pattern of potassium was similar to As, whereas other elements (Ca, Cl, K, Mg, P and S) were distributed differently.XANES analyses showed that approximately 75% of the As in fronds was present in the As(III) oxidation state and the remaining as As(V).