Electron-opaque fibrils and granules in and between the cell walls of higher plants

Abstract

The components of higher-plant cell walls which become electron-opaque after staining with rutheniumosmium were studied by electron microscopy. A fibrillar material which absorbs this stain is a major wail constituent in the root epidermal cells of carrot and morning glory. In both form and size, these fibriis resemble those found on the surface of suspension- cultured cells of the same species Some cells of woody species show an irregular distribution of eIectron-opaque material in the cell wall matrix and middle lamella. This material, which has an amorphous appearance with many electron stains, is shown by rutheniumosmium staining to be an aggregate of discrete granules, 150-220 A in diameter. These observations are not consistent with the concept of the cell wall mamx and middIe lamella as an amorphous, umform gel. © 1972, Rockefeller University Press., All rights reserved.