Effects of GA3 on Puffing and Levels of GA-like Substances and ABA in the Peel of Satsuma Mandarin (Citrus unshu Marc.)1

Abstract

Abstract GA3 was applied to satsuma mandarin fruit at the concn of 100 ppm 25 and 35 days before harvest. The percentage puffy fruit was greater in the untreated than in both treated plots at harvest time. Chlorophyll was more abundant in the peel of treated fruits than in those of the untreated. GA-like substances in the peel decreased rapidly in untreated fruit in early September, then leveled off toward maturity. They increased more than 40 times in the flavedo of treated fruit as compared with the control. ABA content in the untreated peel increased gradually during early fruit enlargement and then increased rapidly to a very high value during maturity. The ABA content in the peel of GA3-treated fruit did not increase at the same rate as the control. Sugar content in the peel was depressed by GA3 application.