Abstract
The changes in sugars in skin of ‘Olympia’ (Vitis vinifera L.×V. labrusca L.) berries were investigated to determine the mechanism of anthocyanin accumulation caused by abscisic acid (ABA) application to the fruit bunch.
A clear increase in anthocyanin accumulation was observed by the ABA treatment during 2_??_3 weeks after veraison, when sugar content began to increase in the skin of berries. By ABA treatment, the content of glucose, fructose and rhamnose increased more rapidly than in the control in the skin.
ABA also stimulated anthocyanin accumulation in the berries cultured in vitro although this stimulation required relatively high temperature and light. This may suggest that the promotion of anthocyanin accumulation following ABA treatment is caused by physiological changes occurring inside the berry, rather than by interactions between the berry and plant. The most probable changes are accumulation of sugars and/or ABA in the grape skin itself.
