Cryostat technique for fresh plant tissues and its application in enzyme histochemistry.

A rapid cryostat technique for sectioning fresh plant tissues is described. The plant tissues are embedded in unfixed brain, frozen with CO2 and sectioned in a cryostat at temperatures ranging from-12° to-18° C for different plant materials. Embedding in brain prevents disruption of plant tissues during freezing and sectioning. The sections are allowed to dry in the cryostat and must be warmed slowly to room temperature before starting histochemical experiments to avoid thawing artefacts.For histological evaluations rapid fixation and staining procedures were elaborated.The reliability of the technique is shown for different tissues of higher plants.Cytochemical localization of some enzymes in meristematic cells is given as an example for the application of the cryostat technique in histochemistry. From the dehydrogenases, NAD-diaphorase is found in the cytoplasm, lactic dehydrogenase seems to be bound to the mitochondria and distributed in the cytoplasm, especially near the nuclear membrane; succinic and isocitric dehydrogenases are localized within the mitochondria. The site of aliesterase activity is close to the plasm membrane. No enzyme activity was found in the nuclei.