In situ analysis of metal(loid)s in plants: State of the art and artefacts

Metals and metalloids play important roles in plant function and metabolism. Likewise, plants subsequently introduce vital dietary nutrition to people and animals. Understanding the transport, localisation and speciation of these elements is critical for understanding availability and metabolic pathways. Subsequently this knowledge can be applied to plant physiology and agricultural research, food science and genetic engineering.This review focuses on the most recent status of in situ techniques to visualise spatial distributions and assess the speciation of metals and metalloids. The techniques addressed include: histochemical analysis, autoradiography, LA-ICP-MS, SIMS, SEM including EDX, PIXE; and synchrotron methods: XRF, differential and fluorescence tomography, and X-ray absorption techniques.This review has been written with the intent of plant researchers to gain familiarity with techniques to which they are not accustom but wish to extend their research with alternative, but complementary, capabilities. Importantly, the disadvantages as well as advantages, have been highlighted for each technique and potential artefacts induced by the analysis or sample preparation are reviewed. These often overlooked aspects are the points critical for novice use of unfamiliar techniques and are offered for advancing research approaches commensurate with the accelerating interest regarding metal(loid)s in botanical specimens.