The use of freeze-substitution in the preparation of plant tissue for ion localization studies

A method, utilizing freeze substitution, is described for the preparation of plant tissue for analytical electron microscopy. The fine structure of the cytoplasm was adequately preserved after freezing leaf tissue in 2-methylbutane at -170°C. Furthermore, following substitution in ether, losses of sodium and potassium from the tissue were less than 4% of the original ion content and the loss of chloride was less than 1%. The merits of the procedure as a means of tissue preparation for ion localization studies are discussed.