ABSCISIC ACID, ISOPENTENYLADENINE AND ISOPENTENYLADENOSINE CONCENTRATIONS IN RIPENING ‘FUERTE’ AVOCADO FRUIT AS DETERMINED BY RADIOIMMUNOASSAY

The effect of ‘Fuerte’ avocado fruit ripening on the concentrations of abscisic acid (ABA) (total and free) in the distal exocarp (rind) and mesocarp plus endocarp (flesh) in early (autumn) and late (late winter) harvested fruit, and isopentenyladenine (2iP) and isopentenyladenosine (IPA) in the distal flesh of late harvested fruit, was studied using radioimmunoassay.

Both total and free ABA trends were essentially similar irrespective of tissue or harvest time.
Total ABA decreased during the very early stages of ripening, but increased again during the middle and latter stages.
Free ABA generally showed a continual increase during ripening.
Total and free ABA concentrations were higher in late harvested material, particularly in the flesh, with the free ABA concentration ranging from 40–130 ng g^-1 fresh mass in early harvested fruit, and 40–195 ng g^-1 in late harvested material.
IPA and 2iP showed maximum levels in the early and latter stages of ripening (20–30 ng g^-1), with markedly lower levels during the middle stages (3–10 ng g^-1).

The significance of these results are discussed with respect to moisture stress and ripening.

V International Symposium on Growth Regulators in Fruit Production

J.G. Cutting, P.J. Hofman, B.N. Wolstenholme, A.W. Lishman

https://doi.org/10.17660/ActaHortic.1986.179.133