Effects of Uniconazole-P on Abscission and Endogenous ABA, IAA, and GA-like Substances Levels of Satsuma Mandarin Fruitlet.

Uniconazole-P, a gibberellin (GA) biosynthesis inhibitor, did not affect growth of mandarin fruitlets definitely but stimulated abscission markedly. Endogenous abscisic acid concentration in fruitlets treated with uniconazole-P was about 4-fold higher compared with the control. Endogenous indole-3-acetic acid and total GAs levels also changed. The relationships between these changes in endogenous hormone levels and fruit abscission were discussed.