Direct analysis of elemental biodistribution in pea seedlings by LA-ICP-MS, EDX and confocal microscopy: Imaging and quantification

Qualitative and quantitative methods were developed for cadmium, lead, cooper and zinc mapping and quantification in root of pea Pisum sativum L Plants were cultivated hydroponically in a Hoagland medium with the addition of 50 mu M of: CdCl2, Pb(NO3)(2), CuSO4, or ZnSO4. After 48 h, parts of roots were cut and analysed. LA-ICP-MS was used for in vivo quantitative imaging of the distribution of metals inthin sections of plant tissues. Calibration curve was obtained using standard addition method NIST SRM 1515 Apple Leaves spiked with standard and application of sulfur isotope as an internal standard. Energy Dispersive X-ray microanalysis Spectroscopy (EDX) was used in order to confirm results obtained by LA-ICP-MS and identify the exact localization of metals deposits in root tissue. In the electron-microscopic photographs we observed deposits of metals in the cell wall, cell membrane, vacuoles, cytoplasm and organelles, such as: mitochondria and peroxisomes. Formation and localization of O-2(-) and H2O2 in cross-sections of root tips was confirmed by confocal microscopy. The presence of metals induced ROS (reactive oxygen species: O-2(-), H2O2) production in areas corresponding to patterns of metals accumulation. (C) 2016 Elsevier B.V. All rights reserved.