A HISTOLOGICAL STUDY OF SUGAR MAPLE DECAYED BY POLYPORUS GLOMERATUS PECK

Abstract

Parenchyma cells of maple wood were found to remain alive, for many years after incorporation into the heartwood In wood invaded by Polyporus glomeratus Peck these cells had been killed in advance of the spreading mycelium, and their contents transformed into masses of dark brown wound gum. These, and similar masses which occasionally formed in the vessels and fibers, gave the outer part of the infected heartwood a characteristic dark color. The presence of wound gum appeared to inhibit development of decay, possibly by reason of the increase in pH with which it has been associated consistently. In tissues containing wound gum, decay was limited to slight delignification of certain cells in the intervessel areas, but following its disappearance disintegration of the tissues was rapid. Variation in resistance to decay was found to be related to variations in the reactions of cell walls to several staining procedures.