CHEMICAL CONTROL OF VEGETATIVE GROWTH AND FLOWERING OF APPLE TREES
It is proposed that the growth regulators TIBA, SADH and CEPA have an indirect, rather than a direct, effect on flower initiation in apple trees. Flower induction in young vigorous trees follows a temporary restriction of vegetative growth, and only occurs after the nutritional requirements for root and shoot growth are satisfied. All three chemicals control growth by inhibiting the production, movement and/or utilization of IAA and possibly GA. Flower initiation follows a period of accumulation of endogenous growth regulators such as cytokinins and sterols which control protein synthesis and other vital processes.
Williams, M.W. (1973). CHEMICAL CONTROL OF VEGETATIVE GROWTH AND FLOWERING OF APPLE TREES. Acta Hortic. 34, 167-174