Improved histochemistry of ripening fruit pulp cells.

The main objective of these study is to elucidate the factors which influence the texture of the fruit pulp, i.e., the cell-wall polysaccharides. Chemical fixation and paraffin embedding have been replaced with a glycol-methacrylate resin (Tecnovit 7100) after an appropriate cycle of cryostabilization. This procedure is far superior to classical fixation and embedding, in maintaining cell structures and biological activity. Very thin sections (1-4 µm) can be cut, with optimal preservation of cell morphology. Specific stains have been employed to reveal the various cell structures and organules: nuclei, cell walls and lipid components. The lytic action of the endogenous polygalacturonase on pectins was revealed by a new tetrazolium salt method.