Ethylene

Ethylene's main function is to ripen fruit. It works by breaking down the cell walls, resulting in a softer texture and releasing the sugars contained within the cells.

Ethylene Chemical bond

Ethylene is a gas unlike most of plant hormones. making it easier to diffuse to nearby fruits and causing them to ripen.

ripen banana Ethylene gas new ripen banana unripen banana
See also:
Abscisic acid
Auxin
Cytokinin