Plant hormones-Ethylene (Structure, Discovery & Biosynthesis) скачать в хорошем качестве

Plant hormones-Ethylene (Structure, Discovery & Biosynthesis)

It is a volatile gas present in the atmosphere as a component of smoke and other industrial gases. It is produced by almost all parts of higher plants and usually present in minute quantity but causes marked effects. Like abscisic acid, ethylene is usually considered as inhibitory hormone. Ethylene is a colorless flammable gas denoted by a formula C2H4 or H2C=CH2 having sweet and musky odour when pure and unsaturated hydrocarbon having double covalent bonds between and adjacent to carbon atoms. In 1864, it was discovered that gas leaks from street lights led to stunting of growth, twisting of plants, and abnormal thickening of stems. In 1874 it was discovered that smoke caused pineapple fields to bloom. In 1901, a Russian scientist Dimitry Neljubow observed that dark-grown pea seedlings growing in the laboratory exhibited symptoms like inhibition of stem elongation stem thickening and horizontal growth. When the plants were allowed to grow in fresh air, they regained their normal morphology and rate of growth. He identified it as ethylene, which was present in the laboratory air from coal gas, as a molecule causing the response. In 1912, A.F. Sievers and R.H. True demonstrated that the combustion gases from the kerosene stove were beneficial in the ripening of lemons. W.C. Crocker and L.I. Knight (1908, 1913) identified ethylene as the active constituent of both, illuminating gas and tobacco smoke. The first report that plant materials evolve ethylene came from H.H. Cousins, who observed that when oranges and banana were stored together during shipping, some gas was emanated from oranges which caused ripening of banana. Sarah Doubt (1917) discovered that ethylene stimulated abscission. R. Gane (1934) provided a chemical proof that ethylene was produced by ripe apples. Since then it has been shown that ethylene is produced from essentially all parts of higher plants. #phytohormones #planthormones #ethylene #plants