Adverse effect of gibberellin on bud development in some stone-fruit plants

Gibberellin stimulates flowering of many plants, under appropriate conditions, but certain concentrations of gibberellin sprayed on branches of some stone-fruit trees at full bloom or at the beginning of pit-hardening retarded development of flower buds. At higher concentrations, vegetative buds as well as flower buds were inhibited. The year following the spray applications, those branches that had received the higher dosages were devoid of flowers or leaves except, in some cases at the tips of the long shoots, on regions which had apparently developed after gibberellin treatment. The terminal buds on the new growth were relatively immune to the adverse effects of gibberellin, while the lateral buds suffered such severe growth inhibition that recovery was impossible. That gibberellin did not inhibit growth in general was evidenced by the excessive length and diameter growth of stems and petioles while lateral bud growth was restricted. The higher the dosages, the more extreme the stem and petiole growth and greater the blocking of bud development.