Investigations of the cell-wall substances of plants, with special reference to the chemical changes taking place during lignification

Abstract

As the result of various investigations, to which, reference will be given in the text of this communication, it is possible to divide the substances which accompany cellulose in the cell-walls of plants among this following groups:— (i) The lignins. (ii) The hemicelluloses. (iii) The pectins. It cannot yet be claimed that any one of the products which can be assigned to these groups has been isolated in the form of a definite chemical entity (with the exception, perhaps, of some products in group iii). There are, however, certain characteristics common to each group, to which brief reference must be made. The lignins appear to be products of high molecular weight, which can be extracted by various somewhat drastic methods from woody tissues. The products obtained by different methods vary in their properties, but they appear to give definite colour reactions with a number of reagents.