Effect of Alcohols and Their Interaction with Ethylene on the Ripening of Epidermal Pericarp Discs of Tomato Fruit

Ethanol concentrations that were induced in pericarp discs of mature-green tomato fruit (Lycopersicon esculentum Mill, cv Castlemart) either by anaerobic metabolism or by exposure to ethanol vapor inhibited ripening without increasing the rate of ion leakage. Inhibition of ripening (i.e. lycopene synthesis) of excised tomato pericarp tissue by ethanol vapor was reversed by increasing concentrations of the plant hormone ethylene. A Lineweaver-Burk plot indicated noncompetitive interaction between ethanol and ethylene. Methanol and n-propanol also inhibited lycopene synthesis without significantly increasing ion leakage. The similar inhibitory effects of methanol, ethanol, and n-propanol at concentrations which did not stimulate ion leakage, and the relationship between activity and lipophilia of the alcohols suggest that their mode of action was through disruption of membranes associated with ethylene action.