AP BIOLOGY

Detailed explanation-1: -An unripe fruit generally has low levels of ethylene. As the fruit matures, ethylene is produced as a signal to induce fruit ripening. Ethylene production continues to increase after harvest, thus decreasing fruit shelf-life, storability capacity, and increasing its susceptibility to pathogen attacks.

Detailed explanation-2: -Ethylene. The hormone ethylene has two functions. It (1) helps ripen fruit and (2) is involved in the process of abscission, the dropping of leaves, fruits, and flowers.

Detailed explanation-3: -In climacteric fruit, the plant hormone ethylene is the major cue that controls most aspects of ripening. By contrast, the ripening of nonclimacteric fruit does not strictly depend on ethylene, and the nature of the triggers of ripening in this type of fruit remains yet to be elucidated.

Detailed explanation-4: -Abscisic acid (ABA) and ethylene are the major regulators of ripening and senescence in both dry and fleshy fruits, as demonstrated by numerous ripening-defective mutants, effects of exogenous hormone application, and transcriptome analyses.