Anthocyanin Accumulation and Sugar Content in the Skin of Grape Cultiver ^|^lsquo;Olympia^|^rsquo; Treated with ABA

Abstract

Changes in sugars in the skin of Olympia (Vitis vinifera L. x V. labrusca L.) grape 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 after ABA treatment 2-3 wk after veraison, when sugar content began to increase in the berry skins. Content of glucose, fructose and rhamnose increased more rapidly in the skin after ABA treatment than in the control. ABA also stimulated anthocyanin accumulation in berries cultured in vitro although this stimulation required relatively high temp. and light. This suggests 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.