ETHYLENE-INDUCED OLIVE ORGAN ABSCISSION: ETHYLENE PULSE TREATMENTS IMPROVE FRUIT-TO-LEAF ABSCISSION RATIOS

Efficient, economical mechanical harvest of olive (Olea europaea L.) fruit requires pretreatment with chemical fruit loosening agents, such as ethylene-releasing compounds (ERCs). ERCs suitably reduce the force required to shake fruits from the tree, but these compounds also cause excessive leaf abscission.
The sensitivity of olive fruit and leaf abscission zones (AZs) to ethylene gas has been examined (Lang and Martin, 1987) with respect to the parameters which constitute ERC treatment inductive activity -i.e. ethylene concentration and duration – and a response surface model has been established using continuous durations of various ethylene gas levels.
The experiments reported here examine fruit and leaf abscission responses to interrupted ethylene gas treatments to partially simulate the "pulses" of ethylene released by ERCs under varying day/night field temperatures.
These manipulations consistently reduce leaf AZ sensitivity to ethylene without affecting fruit AZ response.
Consequently, the fruit-to-leaf (F/L) abscission ratio increased to values as high as 66, whereas F/L values of the continuous ethylene abscission model did not exceed 14.

Manipulation of Ethylene Responses in Horticulture, XXII IHC

G. A. Lang, George C. Martin

https://doi.org/10.17660/ActaHortic.1987.201.5