Methods to Visualize Elements in Plants.

Peter M Kopittke,Enzo Lombi,Søren Husted,Daniel P Persson,Katie L Moore,Antony Van Der Ent,Jamie S Laird,Peng Wang

doi:10.1104/pp.19.01306

Abstract

Understanding the distribution of elements in plants is important for researchers across a broad range of fields, including plant molecular biology, agronomy, plant physiology, plant nutrition, and ionomics. However, it is often challenging to evaluate the applicability of the wide range of techniques available, with each having its own strengths and limitations. Here, we compare scanning/transmission electron microscopy-based energy-dispersive x-ray spectroscopy, x-ray fluorescence microscopy, particle-induced x-ray emission, laser ablation inductively coupled plasma-mass spectrometry, nanoscale secondary ion mass spectroscopy, autoradiography, and confocal microscopy with fluorophores. For these various techniques, we compare their accessibility, their ability to analyze hydrated tissues (without sample preparation) and suitability for in vivo analyses, as well as examining their most important analytical merits, such as resolution, sensitivity, depth of analysis, and the range of elements that can be analyzed. We hope that this information will assist other researchers to select, access, and evaluate the approach that is most useful in their particular research program or application.

Highlights

Visualizing elements in plants is essential for a broad range of studies, including those aiming to improve plant nutrition and crop productivity, improving the nutritional content of edible portions of plants for human nutrition, and for reducing concentrations of harmful contaminants in food and in the broader environment
Understanding the distribution of elements within plant tissues is critical for a range of research programs within plant science, including for functional characterization in molecular biology, improving plant nutrition and productivity, improving human nutrition, and understanding toxic elements in plants and tolerance mechanisms
Ability to analyze hydrated tissues and conduct in vivo analyses, as well as comparing the resolution, sensitivity, depth of analysis, and the range of elements that can be analyzed for seven different approaches, we hope that this information will assist other researchers to select and access the approach that is most useful for use in their particular research program

Summary

Introduction

Visualizing elements in plants is essential for a broad range of studies, including those aiming to improve plant nutrition and crop productivity, improving the nutritional content of edible portions of plants for human nutrition, and for reducing concentrations of harmful contaminants in food and in the broader environment. A variety of approaches can be used for visualizing the distribution of elements within plants These techniques have their own advantages and disadvantages, and for many researchers, selecting the most appropriate technique and to evaluate the data from individual techniques can be challenging. These various techniques differ in the range of elements that can be analyzed, their detection limits, ability to be quantitative, their resolving power, and whether specimens can be examined fresh or frozen hydrated (without sample preparation) or whether dehydration (such as freeze-drying) prior to analysis is required. This is not discussed in detail here, but rather, the reader is referred to other reviews

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