Afterripening

Afterripening is a term used in plant science to describe physiological changes that occur after a period of maturity, most commonly in seeds and harvested fruits, which affect germination or ripening when conditions change.

In seeds, afterripening refers to a dry-storage–dependent loss of physiological dormancy. Seeds produced with dormancy may remain unable to germinate until they lose this dormancy during exposure to dry storage after harvest. The process is associated with hormonal changes, particularly a decrease in abscisic acid relative to gibberellins, and with changes in seed coat permeability and embryo growth potential. It requires time in dry storage at relatively low moisture and moderate temperatures; duration is species-specific and can last from weeks to months. Afterripened seeds generally exhibit higher germination percentages and more uniform germination. If a seed does not afterripen, germination may be delayed or uneven.

Afterripening is distinct from stratification, which uses cold, moist treatment to break dormancy. In seeds, stratification promotes germination by mimicking seasonal cues, whereas afterripening occurs during dry storage without deliberate moisture or cold treatment.

In horticulture, the term can also describe postharvest ripening of fleshy fruits. In climacteric fruits such as peaches, bananas, and tomatoes, harvest initiates continued respiration and ethylene production, driving softening, color change, sugar accumulation, and aroma development. Non-climacteric fruits exhibit ripening that is less dependent on ethylene.

Overall, afterripening encompasses two related but separate processes: the seed-dormancy–breaking changes that occur during dry storage, and the postharvest maturation changes that occur in some fruits after harvest.