ETHYLENE METABOLISM IN TOMATO FRUIT: III. EFFECT OF 2,4-DINITROPHENOL ON RESPIRATION, ETHYLENE EVOLUTION, AND RIPENING

Abstract

The role of phosphorylation in fruit ripening was investigated by the introduction of a phosphorylation uncoupling agent, 2,4-dinitrophenol (DNP), into intact fruit. DNP produced a large increase in carbon dioxide evolution by mature green tomatoes, but not by tomatoes in earlier or later stages of maturity. In contrast to its effect on carbon dioxide production, DNP treatment of mature green tomatoes resulted in an immediate depression of ethylene evolution and in failure of the fruit to ripen normally. This suggests a requirement for oxidative phosphorylation for fruit ripening and ethylene production. It was also observed that cell walls of mature green tomatoes treated with the uncoupling agent became wavy and greatly thickened.