Here it travels from cell to cell in the symplast and phloem. Some times the ethylene synthesis is induced by a high concentration of auxin. Not only does ethylene act as a growth inhibitor but also has many effects on the aging of plant6s. Fruit ripening and leaf abscission are the two areas where the hormones have been studied the most. The aging process is when the cell walls degrade, which makes the fruit softer as well as the chlorophyll content decrease and the fruit looses its greenness.
Ethylene also causes ripened fruit to drop from the plant.
The hormone triggers senescence, then the aging cells release more ethylene. Since ethylene is a gas it travels from fruit to fruit. Therefore one rotten fruit could ruin the whole bunch. If you leave fruit in a bag it allows the ethylene to accumulate. Some fruits are treated with carbon dioxide to retard the again.