Effects of Oxygen Concentration and Ethephon upon the Respiration and Ripening of Banana Fruits

Abstract

A respiratory climacteric and accumulation of soluble solids of pulp were induced in banana fruits by (2-chlorethyl) phosphonic acid (ethephon) at oxygen concentrations of 3–21% (v/v). However, induction of peel colour change by ethephon was retarded or prevented at oxygen concentrations of 10% (v/v) or less. Thus pulp tissue ripened whilst the peel remained green. Respiration rate, soluble solids content of pulp, and peel colour were not affected by ethephon at oxygen concentrations of 1% (v/v) or less. The kinetics of respiratory response to ethephon are consistent with a model in which ethylene (derived from ethephon) is a coupling-activator of respiration. In this model ethylene decreases the affinity of an enzyme system for its substrate, but accelerates the release of product.