Cadmium and zinc localization by SIMS in leaves of Populus deltoides (cv. Lena) grown in a metal polluted soil

Poplar (Populus) species can relatively accumulate high concentrations of heavy metals such as cadmium and zinc in their aboveground tissues. Cd accumulation in poplar is 30 times higher as compared to other woody species. Zn concentrations in leaves ranged from 200 to 1000 mg kg(-1) dry weight (DW) and Cd concentrations from 10 to 70 mg kg(-1) DW on metal polluted sites. These plants possess effective mechanisms for heavy metal translocation into aerial parts. However cellular localization of zinc and cadmium is still unknown in these species. In order to elucidate the precise localisation of these elements, leaves of poplar (Populus deltoides cv. Lena) was grown on metal polluted soil and analysed by SIMS. Using primary gallium source (FIB) mounted on IMS-6f, it was possible to performed secondary ions positives images with a lateral resolution above to 100 nm. In this study, SIMS analysis has been performed on cross section of leaves. Results were compared with global measurement performed by ICP-AES on reference sample (no contaminated) and poplar exposed to metals. Elemental maps of cadmium and zinc were obtained which revealed the high concentrations of metals in both the mesophyll and in the epidermal cell layer. Copyright (C) 2010 John Wiley & Sons, Ltd.