Hydroperoxide levels were determined in aqueous and lipid extracts from fruit of tomato (Lycopersicon esculentum Mill.) at 6 different stages of ripening. An increase in the levels of peroxides in both the aqueous and the lipid fractions was associated with the upsurge in ethylene evolution. The changes in peroxides in the lipid fraction corresponded to the changes in the activity of lypoxygenase. Peroxides may constitute some of the active oxygen forms occurring in vivo which are required for the synthesis of ethylene in fruit.
Received for publication May 17, 1977. This work was done while the authors were, on sabbatical leave from the Department of Horticulture and Forestry, Rutgers — The State University, New Brunswick, N.J. 08903, U.S.A.; and the Department of Food and Nutrition, Faculty of Home Economics, the University of Manitoba, Winnipeg, Canada R3T 2N2, respectively.