Observations on the nature, distribution and development of certain cell-wall constituents of plants

Abstract

The possible relationships between pectins, hemicelluloses and lignin in the plant were studied by investigation of their distribution in pods of beans and peas during development and ripening and in woody shoots of rose. No evidence of any transformation of pectin was found, though its rate of formation decreases in the later stages of growth in the rose. The hemicelluloses of bean and pea pods decrease at the end of ripening, mainly owing to loss of hexosan. Exps. on the starvation and drying of detached leaves (bean, vine, maize) indicated that the pectins were unaffected by the processes; the hemicelluloses were found more labile, and some were possibly used in respiration. Hemicelluloses of leaves were isolated and investigated. The insoluble hemicellulose ("A") has been shown in many-cases to consist of galactan only; in the soluble hemicelluloses, uronic anhydride units are present. Grass and hay were analyzed; little change in the cell-wall material takes place in the conversion of grass to hay. It is not considered that pectin is a precursor of lignin, though it may change slowly into hemicelluloses of the araban type.