Ethylene

Ethylene is a small hydrocarbon gas denoted by the formula C2H4 or H2C=CH2[1]. It is a plant growth regulator that plays a crucial role in various plant processes, including senescence, ripening, and abscission[1]. Ethylene is produced naturally by plants and is involved in regulating and stimulating the opening of flowers, fruit ripening, and shedding of leaves[1]. It is also used in agricultural practices to ripen fruits, induce seed germination, and promote root growth[1].

Ethylene is the simplest alkene and the second simplest unsaturated hydrocarbon[1]. It has a "sweet and musky" odor when pure and is a flammable gas[1]. The IUPAC name for ethylene is ethene[1].

In the chemical industry, ethylene is used to produce polyethene, which is extremely produced using ethylene[1]. Ethylene is also used in agricultural practices to ripen fruits, induce seed germination, and promote root growth[1].

Ethylene acts as a plant hormone, regulating and stimulating various plant processes[1]. It is produced in all parts of grown plants, including roots, stems, tubers, leaves, flowers, fruits, and seeds[1]. Ethylene is involved in stimulating fruit ripening, determining the sex of a flower, inducing seed germination, and promoting root growth[1]. It also affects gravitropism, stimulates nutational bending, and inhibits stem growth[1].

In addition to its role in plant biology, ethylene is an important industrial organic chemical[4]. It is produced by heating natural gas or petroleum to high temperatures, giving a mixture of gases from which the ethylene is separated[4]. Ethylene is used as a monomer to construct longer carbon chains, and it is also used as a starting material for other two-carbon compounds[4]. The polymerization of ethylene gives polyethylene, a polymer with many uses, particularly in the production of packaging films, wire coatings, and squeeze bottles[4].

Ethylene is also used in the formation of linear α-olefins, which have a number of applications, including the preparation of linear low-density polyethylene[4]. Ethylene is the starting material for the preparation of a number of two-carbon compounds, including ethanol, ethylene oxide, acetaldehyde, and vinyl chloride[4].

In the context of fruit ripening, ethylene is a gaseous plant hormone that plays an important role in inducing the ripening process for many fruits, together with other hormones and signals[5]. Ethylene production can be manipulated in different ways in preharvest and postharvest to influence ripening[5]. For example, Ethephon is an ethylene-releasing chemical that can be applied as a preharvest growth regulator to promote fruit ripening, while ReTain inhibits the production of ethylene to decelerate the ripening process[5]. Harvista binds to ethylene receptors in the fruit, blocking the fruit from "seeing" the ethylene and delaying ripening[5].

Overall, ethylene is a crucial molecule in both plant biology and industrial applications, playing a significant role in regulating plant growth and development, as well as being a key component in the production of various chemicals and materials.

Citations:

[1] https://byjus.com/biology/ethylene/

[2] https://www.acs.org/molecule-of-the-week/archive/e/ethylene.html

[3] https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-016-0230-0

[4] https://www.britannica.com/science/ethylene

[5] https://extension.umd.edu/resource/ethylene-and-regulation-fruit-ripening