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lignin
lig·nin L0166500 (lĭg′nĭn)n. A complex polymer, the chief noncarbohydrate constituent of wood, that binds to cellulose fibers and hardens and strengthens the cell walls of plants.lignin (ˈlɪɡnɪn) n (Biochemistry) a complex polymer occurring in certain plant cell walls making the plant rigidlig•nin (ˈlɪg nɪn)
n. an organic substance that, with cellulose, forms the chief part of woody tissue. [1815–25; < Latin lign(um) wood + -in1] lig·nin (lĭg′nĭn) A complex organic compound that binds to cellulose fibers and hardens and strengthens the cell walls of plants. It is the chief noncarbohydrate constituent of wood.Thesaurus| Noun | 1. | lignin - a complex polymer; the chief constituent of wood other than carbohydrates; binds to cellulose fibers to harden and strengthen cell walls of plantspolymer - a naturally occurring or synthetic compound consisting of large molecules made up of a linked series of repeated simple monomerswood - the hard fibrous lignified substance under the bark of trees |
Translationslignin
lignin (lĭg`nĭn), a highly polymerized and complex chemical compound especially common in woody plants. The cellulose walls of the wood become impregnated with lignin, a process called lignification, which greatly increases the strength and hardness of the cell and gives the necessary rigidity to the tree. It is essential to woody plants in order that they stand erect.Lignin a complex polymeric compound contained in the cells of vascular plants. It is one of the lining substances of the sheath of plant cells. The deposition of lignin in the cell membranes produces lignification of the cells and increases their strength. The wood of deciduous trees contains 20–30 percent lignin; that of coniferous varieties, up to 50 percent. Lignin has not been found in lower plants (algae and fungi or mosses). The ultrastructure of lignified cell membranes may be compared to the structure of reinforced concrete: the microfibrils of cellulose correspond in their properties to the reinforcement rods, and the lignin, which has high compressive strength, corresponds to the concrete. The chemical composition of lignin has not been conclusively established. The lignin molecule consists of the products of polymerization of aromatic alcohols, and the basic monomer is coniferyl alcohol: 
Lignin is an amorphous substance, yellowish brown in color; it is insoluble in water and organic solvents. It is stained by basic dyes and yields color reactions characteristic of phenols. The biosynthesis of lignin has not been completely studied. Its precursor is shikimic acid, which is also the case for a number of other aromatic compounds in plants. The formation of lignin takes place through the following basic stages: shikimic acid phenylalanine → cinnamic acid → ferulic acid → coniferyl alcohol → lignin. REFERENCESKretovich, V. L. Osnovy biokhimii rastenii, 5th ed. Moscow, 1971.
Frey-Wyssling, A., and K. Mühlethaler. Ul’trastruktura rastitel’noi kletki. Moscow, 1968. (Translated from English.)
Biokhimiia fenol’nykh soedinenii. Edited by J. Harborne. Moscow, 1968. (Translated from English.)N. D. GABRIELIANLignin is produced in industry as a by-product of the production of cellulose (sulfate lignin, ligninsulfonic acids) and the hydrolysis of plant materials (hydrolytic lignin). Lignin is a valuable chemical raw material; as yet, far from complete use is being made of it. Sulfate lignin can be used as a strengthener in synthetic rubber and as a plasticizer in ceramic production. Ligninsulfonic acids are used as inexpensive strengtheners and binders in foundry work and as additives to the charge in cement production. Hydrolytic lignin is used in the production of lignite, active carbon, and porous brick and for the evolution of nitrolignin, which decreases the viscosity of clay mortars used in drilling.REFERENCESNikitin, N. I. Khimiia drevesiny i tselliulozy. Moscow-Leningrad, 1962.
Brauns, F. E., and D. A. Brauns. Khimiia lignina. Moscow, 1964. (Translated from English.)
Khimiia drevesiny. Edited by B. L. Browning. Moscow, 1967. (Translated from English.)A. N. KISLITSYNIn medicine, “lignin” or “wood wool” is the name for very thin corrugated sheets produced from the wood of coniferous trees by mechanical and chemical processing and used as surgical dressings.lignin[′lig·nən] (biochemistry) A substance that together with cellulose forms the woody cell walls of plants and cements them together. (materials) A colorless to brown substance removed from paper-pulp sulfite liquor. lignin1. An organic substance in wood that, with celluloses, forms the principal constituent of wood tissue. 2. A crystalline product recovered from paper pulp; used in the manufacture of plastics, as a binder in wood chipboard, and for anticorrosive coatings.lignin
lignin [lig´nin] a woody substance closely associated with cellulose in plants and grouped with the polysaccharides, although it is not actually a carbohydrate; it combines with bile acids to prevent their absorption. Lignin fibers are less digestible by gut bacteria than other polysaccharides.lig·nin (lig'nin), A random polymer of coniferyl alcohol accompanying cellulose and present in vegetable fiber and wood cells; a source of vanillin (by oxidation of lignin); lignin composition varies with plant species. It is one of the most abundant biopolymers in nature. [L. lignum, wood] lignin (lĭg′nĭn)n. A complex polymer, the chief noncarbohydrate constituent of wood, that binds to cellulose fibers and hardens and strengthens the cell walls of plants.lig·nin (lig'nin) A water-insoluble fiber found in wheat bran, whole grains, and vegetables. [L. lignum, wood]lignin a complex, noncarbohydrate polymer found in cell walls, whose function is to provide mechanical support to the cell, as in xylem VESSELS and bark fibres. Such cells are said to be ‘lignified’, the lignin being laid down by the cell on the inside of the cellulose cell wall and, since lignin forms an impermeable barrier, the cells are dead.lig·nin (lig'nin) A water-insoluble fiber found in wheat bran, whole grains, and vegetables. [L. lignum, wood]lignin
Related to lignin: hemicelluloseWords related to ligninnoun a complex polymerRelated Words |