• Ethylene (not to be confused with its more famous cousin ethyl alcohol) is the simplest of plant hormones. In fact, it is the simplest of the double bonded carbon compounds, the alkenes.
  • The chemical formula of ethylene (a gas at room temperature) is C2H4. Two carbon atoms are double bonded together (like this: C=C) with each carbon atom having two attached hydrogen atoms.
  • As far as biologically active organic molecules go, six atoms is about as small as it gets. Despite its diminutive size, ethylene has a significant effect on plant growth and development.
  • Ethylene’s effect on plants has been observed since ancient times. The list of activities is large, and includes roles in leave abscission, seed germination, root hair formation, pollination, gravitropism, and many others.
  • The most well-known function of ethylene in plants is in fruit ripening. Plants release ethylene as fruits ripen, and this stimulates the production of more ethylene, which makes the fruit ripen even more.
  • Ethylene is a problem when it comes to shipping produce from farm to point of sale. Plants often release the gas during transit which can lead to greatly shortened shelf life.
  • Plants sense ethylene in the environment by using protein receptors inside the cell. One way to inhibit the ethylene response is to occupy the receptors with a structurally similar but non-bioactive compound.
  • Ethylene is sometimes used commercially to speed up the development of flowering in some plants, leading to earlier fruit production.
  • Want to experiment with the effects of ethylene? Place an old banana peel next to a plant and look for a response.
  • We can thank ethylene for the old saying “one bad apple spoils the whole bunch.” It was noticed long ago that the presence of an overripe apple causes neighboring apples to ripen faster, maybe even too fast. Ethylene at work.