Direct fluorescence imaging of cell walls in plant roots and stems

Investigating plant structure has long been fundamental to botanical science. Across disciplines, including plant development, ecophysiology, and biotechnology, particular interest has focused on the complex structure of lignocellulosic walls. The lignified and suberized cell walls have vital physiological functions in structural support, defence, and water transport, and no less importantly, constitute a major part of the terrestrial biomass. Microscopy is critical to studies focussed on plant cell walls, with classical methods developed in the 1960s still popular to this day. However, recent innovations in tissue preparation, fluorescence staining and microscopy equipment offer advantages over traditional practices.

In their new paper published in AoBP, Kitin et al. review recent innovations in tissue preparation and fluorescence staining for lignin and suberin. They demonstrate simple and cost-effective protocols for preparation of plant samples for microscopy using hand-cut sections cleared with glycerol. Autofluorescence of lignin in combination with direct stains, such as Congo red and fluorol yellow, was shown to clearly differentiate between lignified, suberized, and unlignified cell walls in stem and root tissue samples. They also managed to use these methods for three-dimensional imaging of plant cells, using wide-field fluorescence or confocal laser scanning microscopy. The authors hope that their methods will help future plant anatomical and histochemical studies by providing data the variety of plant cell types and cell wall components.