DISTRIBUTION OF ABSCISIC-ACID IN DIFFERENT PARTS OF THE REPRODUCTIVE-ORGANS OF TOMATO

The distribution of abscisic acid (ABA) in reproductive organs of tomato (Lycopersicon esculentum Mill. cultivar 'Zuisyu') from buds to fruits, was determined. The fresh weights of the pistil and calyx increased nearly two-fold from 5 days before flowering, but their ABA concentrations remained more or less constant. Five days before flowering, the ABA concentration of the stamens and petals were higher, but decreased to about one-sixth on the days of flowering. Ten days after flowering, pollinated ovaries had less ABA than unpollinated ones. In fruits, ABA concentrations changed in the various parts, independent of each other. High concentrations of ABA were encountered in the pericarp, axis and the locule tissue in the early growth stages. Even around 50 days after flowering, the locule tissue had a small peak of ABA concentration. These results show accumulation of ABA in various regions of the flower and the fruit, independently of each other, at specific growth stages, suggesting specific role(s) for ABA in reproductive development.