Application of 1-MCP and propylene to identify ethylene-dependent ripening processes in mature banana fruit

Mature green bananas (Musa sp., AAA group, Cavendish subgroup, cultivar 'Williams') were treated with 1-methylcyclopropene (1-MCP) at a preclimacteric stage and at intervals of 6, 12 and 24 h after propylene treatment (HAPT) to initiate ripening. The fruit were then allowed to ripen in air or propylene. Ethylene production, respiration rates, peel colour and total volatiles production were monitored during ripening. 1-MCP significantly delayed the onset and affected the rate and magnitude of several physiological responses. Application of 1-MCP at a preclimacteric stage or 6 and 12 HAPT delayed onset of the ethylene and respiratory climacterics, peel degreening and total volatiles production. Application of 1-MCP 24 HAPT after autocatalytic ethylene had commenced did not inhibit development of the ethylene and respiratory climacterics, but delayed colour development and total volatiles production. In all cases, when 1-MCP treated fruit did produce ethylene, rates of production were significantly enhanced, whilst rates of respiration were always lower. Onset of total volatiles production was delayed and the rates were lower in all 1-MCP treated fruit. Degreening of the peel was significantly delayed and disrupted by 1-MCP. The results show that these ripening related processes, once engaged with autocatalytic ethylene production, become partially independent of further ethylene action. Some possible reasons for the failure of 1-MCP treated fruit to ripen normally are discussed. (C) 1998 Elsevier Science B.V. All rights reserved.