Roles of ACC and glutathione during breaking of dormancy in grapevine buds by high temperature treatment

Abstract

The changes in ACC and glutathione and their effects on the breaking of bud dormancy of grapes by high temperature treatment (45 °C water soaking for 4 hours) were investigated High temperature treatment increased ACC content and ethylene production in 'Delaware' grape cuttings and their levels remained higher than that of the control for 21 days after treatment, but they decreased and became lower than that of the control after budbreak. The level of reduced glutathione (GSH) in cuttings exposed to high temperature was consistently higher than that of the control 3 days after treatment, but the situation was reversed for oxidized glutathione (GSSG). Apparently GSH broke bud dormancy, but GSSG inhibited it. These results indicate that dormancy of grapevine buds is broken when GSSG converts to GSH, and that cyanide produced during ethylene biosynthesis may stimulate the conversion.