Occurrence of Endogenous Ethylene and Effect of Plant Regulators on Ethylene Production in the Grapevine

Abstract

Accepted for publication September 14, 1978. Ethylene production in Thompson Seedless flowers and berries reached a peak at bloomtime. From bloom to fruit-set there was a sharp decrease, then a gradual one through July 21. There was a slight temporary rise in ethylene production in the berries on August 2. Production was generally less in Carignane than in Thompson Seedless, but production curves were similar. In the leaves most of the ethylene production occurred in the first expanding leaf below the shoot apex, followed by the second and third leaves. Production was low in the other leaves.

Ethephon produced the most ethylene of all the growth regulators tested. The maximum effect was usually in half-expanded leaves. In Carignane, ethephon sharply increased ethylene production by berries almost tenfold. BOA (benzothiozole-2-oxyacetic acid) and GA₃ gibberellic acid) also increased production, but to a lesser degree.

The ethylene curve for Thompson Seedless berries was similar to that for Carignane. BOA induced a high rate of ethylene evolution in Thompson Seedless berries six hours after treatment, but this was followed by a steady decrease. Other growth regulators also increased ethylene evolution.