Climacteric

The climacteric is a stage of fruit ripening associated with increased ethylene production and a rise in cellular respiration. Apples, bananas, melons, apricots, and tomatoes (among others) are climacteric fruit. Citrus, grapes, and strawberries are not climacteric (they ripen without ethylene and respiration bursts). However, nonclimacteric melons and apricots exist, and grapes and strawberries harbour several active ethylene receptors. Climacteric is the final physiological process that marks the end of fruit maturation and the beginning of fruit senescence. Its defining point is the sudden rise in respiration of the fruit and normally takes place without any external influences. After the climacteric period, respiration rates (noted by carbon dioxide production) return to or below the point before the event. The climacteric event also leads to other changes in the fruit, including pigment changes and sugar release. For those fruits raised as food, the climacteric event marks the peak of edible ripeness, with fruits having the best taste and texture for consumption. After the event, fruits are more susceptible to fungal invasion and begin to degrade with cell death.