Lombi Enzo, Zhao Fang-Jie, Fuhrmann Mark, Ma Lena Q, McGrath Steve P
Agriculture and the Environment Division, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK.
Environmental Sciences Department, Brookhaven National Laboratory, Building 830, N. Railroad St., Upton, NY 11973-5000, USA.
New Phytol. 2002 Nov;156(2):195-203. doi: 10.1046/j.1469-8137.2002.00512.x.
• 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).
• 蜈蚣草是首例被报道的砷超富集植物，目前对该植物砷超富集机制的了解尚少。
• 运用化学分析和能量色散X射线微区分析（EDXA）研究了砷在整株植物（叶片）及细胞水平的分布情况。利用X射线吸收近边结构（XANES）分析确定了叶片中砷的形态。
• 大部分砷存在于羽片（占总砷量的96%）中。羽片中砷的浓度从叶片基部向顶端递减。孢子和叶脉中的砷浓度远低于羽片。EDXA分析表明，砷主要分隔在上、下表皮细胞中，可能存在于液泡中。钾的分布模式与砷相似，而其他元素（钙、氯、钾、镁、磷和硫）的分布则有所不同。
• XANES分析显示，叶片中约75%的砷以As(III)氧化态存在，其余为As(V)。
