The accumulation of the isoflavonoid phytoalexin, glyceollin, occurs in hypocotyls of green soybean seedlings (Glycine max L. Merr. cv Harosoy 63) in response to the injection of a glucan elicitor isolated from the mycelial walls of the fungus, Phytophthora megasperma f. sp. glycinea. This accumulation, which levels off after 24 hours, is preceded by a dramatic, transient rise in extractable ac...