PLANT MICROTECHNIQUE: SOME PRINCIPLES AND NEW METHODS

Concepts

MedicinePlant BiologyPlant SciencesHistologyPlant Cell BiologyPlant HistologyHistological StainingStaining TechniquesTissue FixationTissue PreparationTissue ProcessingAldehyde FixationChemical FixativesCytological PreservationGlutaraldehyde FixationMorphologic PreservationOsmium Tetroxide FixationPreservation Methodology

TL;DR

Common plant histology fixatives and embedding media often destroy or distort fine cellular structures, but suitable alternatives can preserve these features. The authors aim to recommend and detail a fixation and embedding protocol that preserves plant cell ultrastructure. They propose using non‑coagulant fixatives such as osmium tetroxide, acrolein, glutaraldehyde, or formaldehyde, followed by embedding in plastic polymers, specifically acrolein fixation and glycol methacrylate embedding. Sections 1–3 µm thick prepared with this protocol exhibited excellent preservation of tissue and cellular structures across a wide range of plant specimens.

Abstract

Some easily seen structural features of living plant cells are destroyed or badly distorted by most of the common fixatives and embedding media used in plant histology. In stained sections of plant tissues fixed in FAA (formalin‐acetic acid‐alcohol mixtures) and embedded in paraffin wax, for example, mitochondria and fine transvacuolar strands of cytoplasm are usually not visible. Many structural features such as these can be preserved, however, with suitable fixatives and embedding media. Specifically we recommend fixation in non‐coagulant fixatives (e.g., osmium tetroxide, acrolein, glutaraldehyde, formaldehyde) and the use of plastics as embedding media, and we describe in detail a method of fixation in acrolein and embedding in glycol methacrylate polymer. In a wide range of plant specimens prepared in this way, stained sections 1–3 microns thick showed excellent preservation of tissue and cell structures.