Off-season Flower Induction of Longan with Potassium Chlorate, Sodium Chlorite, and Sodium Hypochlorite

Abstract

Flower induction of longan (Dimocarpus longan) with potassium chlorate has improved the availability of longan fruit, but potassium chlorate is potentially explosive and often difficult to purchase, transport, and store. Previous reports suggested that hypochlorite enhances natural longan flower induction. This study is the first to demonstrate that chlorite- and hypochlorite- (bleach) induced off-season longan flowering is similar to chlorate-treated trees. Hypochlorite induction of flowering with bleach was likely the result of chlorate in the bleach solution. Chlorate was present in the leachate from potted longan trees treated with bleach and was detected in bleach before soil application. The quantity of chlorate found in bleach induced flowering to the same or greater extent as equivalent quantities of potassium chlorate, suggesting chlorate is an a.i. responsible for longan flowering.