Spatial distribution of cadmium in leaves of metal hyperaccumulating Thlaspi praecox using micro-PIXE


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Marjana Regvar
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  • • Localization of cadmium (Cd) and other elements was studied in the leaves of the field-collected cadmium/zinc (Cd/Zn) hyperaccumulator Thlaspi praecox from an area polluted with heavy metals near a lead mine and smelter in Slovenia, using micro-PIXE (proton-induced X-ray emission).
  • • The samples were prepared using cryofixation. Quantitative elemental maps and average concentrations in whole-leaf cross-sections and selected tissues were obtained.
  • • Cd was preferentially localized in the lower epidermis (820 µg g−1 DW), vascular bundles and upper epidermis, whereas about twice the lower concentrations were found in the mesophyll.
  • • Taking into account the large volume of the mesophyll compared with the epidermis, the mesophyll is indicated as a relatively large pool of Cd, possibly involved in Cd detoxification/dilution at the tissue and cellular level.