Mangoes (var. Tommy Atkins) were exposed to ethylene and acetylene over a range of concentrations at high humidity for 24 h at 25°C, then ripened in air alone. Ripeness was assessed after 4 and 8 days by analysis of texture, colour development, soluble solids and acid contents.

Ethylene in air at concentrations of 0.01 ml litre-1 and above or acetylene at 1.0 ml litre-1 were found to initiate ripening. Treatment with 0.01 ml litre-1 acetylene resulted in limited softening but had no effect on the other ripening changes analysed. Individual ripening processes responded differently to treatment: texture changes were most rapidly affected, while the rate of acidity losses was often reduced in ethylene treated fruits. Acetylene-treated fruits at concentrations of 0.01 and 0.1 ml litre-1 showed delayed ripening when compared to those treated with either 1.0 ml litre-1 acetylene or ethylene. Increased acetylene concentrations of 2.0 ml litre-1 gave a similar response to 1.0 ml litre-1, although in some instances there were indications of inhibitory effects.