[Cell wall breakdown in wilting flowers of Ipomoea tricolor Cav].

In Ipomoea tricolor senescence of the corolla is characterized by a decrease of hemicellulose and cellulose contents by 43% and 40%, respectively. Concomitant with the mobilization of cell wall polysaccharides the activities of various glycosidases, β-glucosidase, β-galactosidase, laminarinase, and cellobiase increase considerably. In contrast, the increase of α-mannosidase activity is less marked and the activity of β-xylosidase reaches its maximum in the course of extension growth of the flower bud. The partial degradation of the cell walls followed by the withdrawal of sugars as well as the mobilization of intracellular compounds may be meaningful with regard to the capacity of Ipomoea to form an enormous number of flowers consecutively.