Nuclear microprobe studies of metal(loid)s distribution in hyperaccumulating plants

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Date
2007-11
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Publisher
Australian Institute of Nuclear Science and Engineering (AINSE)
Abstract
Micro-proton-induced X-ray emission (μ-PIXE) spectroscopy was used to determine in situ elemental concentrations of nickel (Ni) and arsenic (As) in leaf and stem tissues of hyperaccumulating plants Hybanthus floribundus subsp floribundus and Pityrogramma calomelanos var. austroamericana, respectively. Nickel concentration in seeds of H. floribundus subsp floribundus was also investigated. Both species were grown in metal(loid) contaminated potting mix for 20 weeks duration under controlled glasshouse conditions. Leaf and stem samples were hand-sectioned, cryo-fixed and freeze-dried in liquid nitrogen before μ-PIXE analysis using the 10-MV tandem accelerator at the Australian Nuclear Science and Technology Organization. In H. floribundus subsp floribundus leaves, Ni was highest in the adaxial epidermal cells (1% dry weight; DW) and least in spongy mesophyll (0.53% DW). In stem tissues, Ni concentrations were highest in the collenchyma (0.25% DW) and there was no clear pattern of Ni localization in seeds. In P. calomelanos pinnules, As localization was relatively uniform across the whole specimen and in stipe tissues, highest concentration occurred in the vascular bundle (0.2% DW). These results suggest that hyperaccumulating plants sequester excess metal(loid)s in different cellular loci and enables us to better understand the physiology and ecology of these hyperaccumulating species.
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Keywords
Semimetals, Plants, PIXE analysis, Nickel, Arsenic, Accelerators
Citation
Kachenko, A. G., Singh, B., Siegele, R., & Bhatia, N. (2007). Nuclear microprobe studies of metal(loid)s distribution in hyperaccumulating plants. Poster presented to the 15th Australian Conference on Nuclear and Complementary Techniques of Analysis and 9th Vacuum Society of Australia Congress, 21st – 23rd November 2007. Melbourne, Australia: University of Melbourne.