Metabolic studies with banana fruit slices: II. Effects of inhibitors on respiration, ethylene production, and ripening

Abstract

Transverse slices of green banana fruit were vacuum-infiltrated with aqueous solutions of 24 potential inhibitors of protein synthesis, respiration, or ethylene production. The effects of these compounds were examined in the absence or presence of 10 p.p.m. ethylene. Of the compounds which produced marked effects mono- fiuoroacetate, 4-hydroxy-2-oxoglutarat(HKG), KCN, and cycloheximide were examined in more detail. Monofiuoroacetate (1 and 2 × 10-2M) and cycloheximide (1 and 2µg/ml) almost eliminated the peaks of induced respiration and ethylene production, almost eliminated the respiratory response to added ethylene, and prevented normal ripening. Ethylene production by slices treated with the inhibitors rose within a few hours after treatment to steady levels considerably above the preclimacteric rates of untreated slices, possibly as a result of cell damage. KCN at 5 × 10-2M caused breakdown of the tissue. At 1 and 2.5 × 10-2M, KCN almost eliminated the peak of induced ethylene production, but only delayed the peak of induced respira. tion and retarded ripening in both ethylene. treated and ungassed slices. Before the resumption of a normal ripening pattern in slices treated with KCN ethylene pro. duction declined to normal preclimacteric rates. HKG at 3 × 10-2M eliminated the induced rise in ethylene production, delayed the peak of induced respiration, and reduced respiration in ethylene-treated slices but did not affect ripening. There is evidence that banana tissue may metabolize HKG and KCN. © 1971 CSIRO.