Abscisic Acid in Fruit Ripening and Postharvest Adaptation: Mechanisms and Quality–Resilience Trade-Offs

Fruit ripening and postharvest processes are examined as distinct physiological phases, while abscisic acid (ABA) is often described as a general promoter of ripening, particularly in non-climacteric fruits. However, despite extensive research on ABA-mediated regulation, no comprehensive review has yet integrated and mechanistically reconciled the diverse and context-dependent effects of ABA reported across fruit development and postharvest physiology. Hence, this narrative review examines the roles of ABA throughout fruit growth, ripening, harvest, and storage to elucidate its regulatory mechanisms and potential applications in fruit production and postharvest management. ABA influences ripening through interconnected physiological modules encompassing sugar metabolism and carbon allocation, pigmentation, cell-wall remodelling, and water relations. Due to the partial coupling of these modules, ABA may enhance edible quality while simultaneously compromising postharvest storability. Harvest further reprogrammes this network under carbon deprivation, dehydration, temperature stress and pathogen pressure, thereby shifting ABA action towards continued ripening, stress adaptation or senescence. Practical value therefore depends on cultivar, developmental stage, dose, application site, environment and compatibility with other treatments. Rather than maximising ABA, effective deployment requires a defined biological window in which gains in marketable quality, harvest coordination or loss reduction exceed penalties to yield, firmness, storability and cost. Future research should resolve tissue-specific ABA flux, decouple quality from stress resilience, and validate treatment windows under commercial conditions.