Reduction and coordination of arsenic in Indian mustard

I J Pickering, R C Prince, M J George, R D Smith, G N George, D E Salt

Research output: Contribution to journalArticlepeer-review

453 Citations (Scopus)

Abstract

The bioaccumulation of arsenic by plants may provide a means of removing this element from contaminated soils and waters. However, to optimize this process it is important to understand the biological mechanisms involved. Using a combination of techniques, including x-ray absorption spectroscopy, we have established the biochemical fate of arsenic taken up by Indian mustard (Brassica juncea). After arsenate uptake by the roots, possibly via the phosphate transport mechanism, a small fraction is exported to the shoot via the xylem as the oxyanions arsenate and arsenite. Once in the shoot, the arsenic is stored as an As-III-tris-thiolate complex. The majority of the arsenic remains in the roots as an As-III-tris-thiolate complex, which is indistinguishable from that found in the shoots and from As-III-tris-glutathione. The thiolate donors are thus probably either glutathione or phytochelatins. The addition of the dithiol arsenic chelator dimercaptosuccinate to the hydroponic culture medium caused a 5-fold-increased arsenic level in the leaves, although the total arsenic accumulation was only marginally increased. This suggests that the addition of dimercaptosuccinate to arsenic-contaminated soils may provide a way to promote arsenic bioaccumulation in plant shoots, a process that will be essential for the development of an efficient phytoremediation strategy for this element.

Original languageEnglish
Pages (from-to)1171-1177
Number of pages7
JournalPlant Physiology
Volume122
Issue number4
DOIs
Publication statusPublished - Apr 2000

Keywords

  • ray-absorption spectroscopy
  • metal-ions
  • plants
  • accumulation
  • volatilization
  • glutathione
  • selenium
  • soil
  • phytoremediation
  • phytochelatin

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