The effect of ethylene and short-chain saturated fatty acids on ethylene sensitivity and binding in ripening bananas

Ethylene-induced ripening of banana fruit depends on the duration of ethylene treatment. Ripening was found to be slower in response to a 6 hour treatment with ethylene than to a 24 hour treatment at the same ethylene concentration. This response of banana fruit to ethylene appears to be related to the binding of ethylene to its receptor sites in the tissue. Treatment with ethylene resulted in the complete saturation of all the available binding sites. This saturation was reversible in the case of a 6 hour exposure to ethylene, and irreversible when the fruit were treated with ethylene for 24 hours. Treatment of green bananas in the preclimacteric stage with octanoic acid resulted in a suppression of ethylene synthesis, possibly as a result of the inhibition of the membrane-associated ethylene forming enzyme, and an increase in the sensitivity of the fruit to ethylene. It appears that the fatty acid may act by changing certain membrane properties which could result in an increase in ethylene binding in the tissue, thus rendering the tissue more sensitive to ethylene.