Ethylene and polyamine synthesis in cherimoya fruit under high CO2 levels.

Abstract

In this work, we studied the effect of short-term high CO2 treatment (20% CO2 plus 20% O2 for 3 days) on both ethylene and polyamine synthesis in cherimoya fruit stored at 20 and 6°C. The decrease in putrescine content, with no variation in ADC activity, and the accumulation of both spermidine and spermine confirm the preferential transformation of the diamine into polyamines in CO2-treated fruit. The absence of autocatalytic or basal ethylene production with no variation in ACC oxidase activity may be due to deviation to the SAM pool towards polyamine synthesis by high CO2 treatment. These metabolic changes may be responsible for the effect of high CO2 levels on delaying cherimoya fruit ripening and maintaining fruit quality during storage at chilling temperature. Our results are discussed in light of the role attributed to polyamines in cytoplasmic pH regulation.