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ethylene
ethylene (ethene) A colourless gaseous hydrocarbon, C2H4, that occurs naturally in plants and acts as a growth substance in a variety of physiological roles. It is produced in response to stresses, such as water shortage, and acts as an effector for auxins: auxins stimulate tissues to produce ethylene, which diffuses rapidly to trigger responses in surrounding cells. The best known effect is the stimulation of fruit ripening: fruits such as bananas, apples, and avocados naturally produce ethylene during the later stages of ripening, and ethylene gas is used to promote the ripening of fruits, such as bananas, that are picked and shipped ‘green’. Ethylene generally suppresses flowering, except in members of the pineapple family (Bromeliaceae) – hence flowering of pineapples may be synchronized by releasing ethylene into the growing crop. Studies have shown varied and often contradictory effects of ethylene on vegetative growth. For example, in rice it acts with gibberellins to promote stem elongation, while in peas ethylene inhibits root and shoot elongation. Seed germination, bud opening, and root initiation may also be promoted by ethylene.
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"ethylene." A Dictionary of Biology. 2004. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "ethylene." A Dictionary of Biology. 2004. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O6-ethylene.html "ethylene." A Dictionary of Biology. 2004. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-ethylene.html |
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ethylene
ethylene or ethene , H 2 C=CH 2 , a gaseous unsaturated hydrocarbon. It is the simplest alkene . Ethylene is colorless, has a faint odor, and has a slightly sweet taste; it melts at -169.4°C and boils at -103.8°C. Because of the presence of the double bond in its molecule, ethylene is very reactive. It burns in air with a luminous flame and forms explosive mixtures with pure oxygen. It combines directly with the halogens, e.g., with chlorine to form 1,2-dichloroethane. With hydrogen it forms ethane. Ethylene may be prepared by the dehydration of ethanol with sulfuric acid at about 180°C. It is prepared commercially from natural gas and petroleum, e.g., by cracking and fractional distillation. Ethylene has many uses. It is important in the synthesis of many chemicals. It is used in making polyethylene and saran, in the manufacture of ethanol and ethylene oxide, and as an anesthetic. Ethylene was called olefiant gas by early chemists. |
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"ethylene." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "ethylene." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1E1-ethylene.html "ethylene." The Columbia Encyclopedia, 6th ed.. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-ethylene.html |
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ethylene
eth·yl·ene / ˈe[unvoicedth]əˌlēn/ • n. Chem. a flammable hydrocarbon gas, C2H4, of the alkene series, occurring in natural gas, coal gas, and crude oil and given off by ripening fruit. It is used in chemical synthesis, esp. in the manufacture of polyethylene. |
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"ethylene." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "ethylene." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O999-ethylene.html "ethylene." The Oxford Pocket Dictionary of Current English. 2009. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-ethylene.html |
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ethylene
ethylene (ethene), a gas of the formula CH2=CH2, produced by fruit as a hormone to speed ripening of climacteric fruits. This explains why some fruits ripen faster if they are stored in a plastic bag. It is used commercially in very small amounts to speed fruit ripening after harvesting.
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DAVID A. BENDER. "ethylene." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. DAVID A. BENDER. "ethylene." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O39-ethylene.html DAVID A. BENDER. "ethylene." A Dictionary of Food and Nutrition. 2005. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O39-ethylene.html |
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ethylene
ethylene See ethene.
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MICHAEL ALLABY. "ethylene." A Dictionary of Ecology. 2004. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "ethylene." A Dictionary of Ecology. 2004. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O14-ethylene.html MICHAEL ALLABY. "ethylene." A Dictionary of Ecology. 2004. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-ethylene.html |
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ethylene
ethylene See ethene
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"ethylene." World Encyclopedia. 2005. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "ethylene." World Encyclopedia. 2005. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O142-ethylene.html "ethylene." World Encyclopedia. 2005. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-ethylene.html |
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ethylene
ethylene See ETHENE.
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MICHAEL ALLABY. "ethylene." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "ethylene." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O7-ethylene.html MICHAEL ALLABY. "ethylene." A Dictionary of Plant Sciences. 1998. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O7-ethylene.html |
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