TRANSLOCATION AND ACCUMULATION OF LABELLED GIBBERELLIC ACID INTO FRUITLETS AND SHOOT APICES OF SWEET CHERRY

On the mature trees of the cv. "Durone della Marca", 3-yr old branches were ringed under their uppermost lateral spur.
At early petal fall [1, 7,12,18–¹⁴C]-GA₃ was applied at four groups of comparable branches, that is: a) into the base of the fruit cluster, competitive with the growing shoot of the same branch, b) into terminal shoot apex, c) into the basal shoot apex, or d) into a fruitlet.
The radioactivity scintillation counting of the purified extracts of these organs showed that the labelled GA₃ moves through the branch towards its growing shoot apex, fruitlets and expanding leaves.
The radioactivity migration appeared related to the type of the sink organs and their growing stage rather than to their distance from the injection site.
Nevertheless labelled GA₃ separately applied to the fruitlet, terminal shoot apex or lateral shoot apex evidenced that: a) a large but different quote of the chemical remained in each injected growing organ; b) the translocation of the hormon varied depending on the treated organ and its growth stage.
GA₃ translocation seems to depend on the shoot-fruitlet competition: the former generally acts as a sink which prevails on the fruitlet, but this ratio can be modified and even reversed by the growing rate of these organs.

Fruit Set and Development, XXI IHC

G. Cristoferi, N. Filiti

https://doi.org/10.17660/ActaHortic.1983.139.21