The effects of ethylene on plants were first noticed in German cities in the 1800 s, when gas street lamps were associated with stunted growth and leaf loss of nearby trees . Ethylene was identified in 1901 as a by-product of combustion , which caused defoliation and inhibited plant growth . The fruit-ripening effects of some fruits on others were noted in 1910 in a Jamaican Dept. of Agriculture report, and the causative agent was later identified as ethylene. The dark spots on the peel of ripe bananas are areas of high ethylene production. It also causes fruit softening by causing the production of the enzymes cellulase and pectinase, which break down cellulose and pectin , structural components of the cell wall.
Ethylene also causes starches to be converted to sugars .
Fruits such as apples, bananas, kiwi, avocado, and tomatoes can be stored under ethylene-free, low oxygen conditions for months without ripening . When they are needed for market, about 1 ppm ethylene is added to the air. These fruits experience a climateric , which is an increase in respiration caused by production of ethylene by the plant itself. Ethylene production following a drop in IAA production by leaves causes the breakdown of the middle lamella and the suberization of cells in the abscission zone, which is followed by leaf drop. Some fruits are sprayed with ethephon , which breaks down to ethylene, to synchronize abscission and allow a shorter harvesting period.