Duckweeds are a common macrophyte in paddy and aquatic environments. Here, we investigated arsenic (As) accumulation, speciation and tolerance of the rootless duckweed Wolffia globosa and its potential for As phytofiltration. When grown with 1 mu M arsenate, W. globosa accumulated two to 10 times more As than four other duckweed or Azolla species tested. W. globosa was able to accumulate > 1000 mg As kg(-1) in frond dry weight (DW), and tolerate up to 400 mg As kg-1 DW. At the low concentration range, uptake rate was similar for arsenate and arsenite, but at the high concentration range, arsenite was taken up at a faster rate. Arsenite was the predominant As species (c. 90% of the total extractable As) in both arsenate-and arsenite-exposed duckweed. W. globosa was more resistant to external arsenate than arsenite, but showed a similar degree of tolerance internally. W. globosa decreased arsenate in solution rapidly, but also effluxed arsenite. Wolffia globosa is a strong As accumulator and an interesting model plant to study As uptake and metabolism because of the lack of a root-to-frond translocation
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机译：浮萍是水稻和水生环境中常见的大型植物。在这里，我们调查了无根浮萍Wolffia globosa的砷（As）积累，形态和耐受性及其As的植物过滤潜力。当用1亩M砷酸盐生长时，W。globosa积累的砷是其他4种浮萍或Azolla物种的2至10倍。 W. globosa能够在叶状干重（DW）中积累> 1000 mg As kg（-1），并耐受高达400 mg As kg-1 DW。在低浓度范围，砷酸盐和亚砷酸盐的吸收速率相似，但在高浓度范围，砷酸盐的吸收速率更快。在砷酸盐和砷暴露的浮萍中，砷都是主要的砷物种（占可提取砷总量的90％）。 W. globosa对亚砷酸盐的耐受性高于对亚砷酸盐的耐受性，但对内部的耐受性相似。 W. globosa迅速降低溶液中的砷酸盐，但也排出了砷酸盐。 Wolffia globosa是一种强大的As积累剂，是一种有趣的模型植物，由于缺乏从根到叶的易位，可以研究As的吸收和代谢
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