Effect of Gibberellic Acid on the Initiation of Flowers and Runners in the Strawberry

Abstract

A NUMBER of long-day responses are induced by the application of gibberellic acid to plants growing in short days. These include the promotion of stem elongation and flower induction in long-day plants¹; inhibition of flower initiation in some short-day plants²; and delay in the onset of autumn colouring and leaf-fall, and renewal of shoot-growth in woody plants³. In the strawberry, flowers are initiated under short-day conditions and branch crowns are formed in the axils of the leaf petioles, which are short and prostrate. During long days, flowers are seldom initiated, runners are formed in the leaf axils and the petioles are long and upright. It has been suggested by one of us⁴ that this greater vegetative vigour is the result of the production during long days of a growth-promoting hormone. The present experiment demonstrates that gibberellic acid can act as a substitute for this natural product.