Microanalysis and microfluorescence application for elemental mapping in Alyssum: techniques results and comparisons.

Localisation of mineral nutrients, K, Ca S and Fe, along with Ni was accomplished within organs and tissues of the Ni hyperaccumulator Alyssum bertolonii and a nonaccumulator congener species Alyssum montanum by means of two physics techniques based on X-ray stimulated emission: microanalysis (SEM/EDX) and microfluorescence (μ-SRXF). These techniques differ in sample preparation, sensitivity, spatial resolution and penetration depth, however they can complement each other in the quality of the information provided. The outcome in both cases consist of a set of elemental distribution maps which also show the content of each element of interest within the tissues of a plant organ cross section. Data from microanalysis give a good spatial resolution, but a penetration depth of only few microns, whereas icrofluorescence allows to go through the whole sample thickness but the spatial resolution coarser than for SEM/EDX. Other differences are highlighted and discussed.