Suberin

Suberin

Suberin is a waxy substance found in higher plants. Suberin is a main constituent of cork, and is named after the Cork Oak, "Quercus suber".

Anatomy and physiology

Suberin is highly hydrophobic and its main function is to prevent water from penetrating the tissue. In roots suberin is deposited in the radial and transverse cell walls of the endodermal cells. This structure is known as the Casparian strip or Casparian band. Its function is to prevent water and nutrients taken up by the root from entering the stele via the apoplast. Instead, water must traverse the endodermis through the symplast. This allows the plant to select the solutes that pass further into the plant. It thus forms an important barrier to harmful solutes. Mangroves use suberin to minimize salt intake from their littoral habitat, for example.

Suberin is found in the phellem layer of the periderm (or cork). This is outermost layer of the bark. The cells in this layer are dead and abundant in suberin, preventing water loss from the tissues below. Suberin can also be found in various other plant structures. For example, the net structure in the rind of a netted melon is suberin.

Structure and biosynthesis

Suberin consists of two domains, a polyaromatic and a polyaliphatic domain. The polyaromatics are predominantly located within the primary cell wall, and the polyaliphatics are located between the primary cell wall and the plasmalemma. The two domains are supposed to be cross-linked. The exact qualitative and quantitative composition of suberin monomers varies in different species. Some common aliphatic monomers include -hydroxyacids (mainly 18-hydroxyoctadec-9-enoic acid) and ,-diacids (mainly octadec-9-ene-1,18-dioic acid). The monomers of the polyaromatics are hydroxycinnamic acids and derivatives, such as feruloyltyramine.

In addition to the aromatics and aliphatics components, glycerol has been reported a major suberin component in some species. The role of glycerol is proposed to interlink aliphatic monomers, and possibly also to link polyaliphatics to polyaromatics, during suberin polymer assembly. The polymerization step of aromatic monomers has been shown to involve a peroxidase reaction.

The biosynthesis of the aliphatic monomers shares the same upstream reactions with cutin biosynthesis, and the biosynthesis of aromatics shares the same upstream reactions with lignin biosynthesis. Lignin and suberin are the only known biological polymers that are irregular.


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  • Suberin — ist ein pflanzliches Biopolymer, das in Zellwänden eingelagert ist. Suberinisierte Zellen finden sich sowohl im Phelloderm als sekundärem Abschlussgewebe als auch in unterirdischen Pflanzenorganen. Namengebend für Suberin ist der Artname der… …   Deutsch Wikipedia

  • Suberin — Su ber*in, n. [L. suber the cork tree: cf. F. sub[ e]rine.] (Bot.) A material found in the cell walls of cork. It is a modification of lignin. [1913 Webster] …   The Collaborative International Dictionary of English

  • Suberīn — Suberīn, so v.w. Kortstoff, s.d …   Pierer's Universal-Lexikon

  • Suberin — Suberīn, Korkstoff, dem Faserstoff ähnliche Substanz, aus den Wandungen des Korkes isoliert, ist wachs oder fettartig, elastisch und rötlichgrau; unlöslich …   Kleines Konversations-Lexikon

  • suberin — [so͞o′bər in, so͞o ber′in] n. [Fr subérine < L suber, cork + Fr ine, INE3] a waxy or fatty substance contained in cork …   English World dictionary

  • suberin — noun Etymology: French subérine, from Latin suber cork tree, cork Date: 1830 a complex fatty substance found especially in the cell walls of cork …   New Collegiate Dictionary

  • suberin — Fatty substance, containing long chain fatty acids and fatty esters, found in the cell walls of cork cells (phellem) in higher plants. Also found in the Casparian band. Renders the cell wall impervious to water …   Dictionary of molecular biology

  • suberin — /sooh ber in/, n. Bot. a waxlike, fatty substance, occurring in cork cell walls and in or between other cells, that on alkaline hydrolysis yields chiefly suberic acid. [1820 30; < L suber cork + IN2; cf. F subérine] * * * …   Universalium

  • suberin — noun A waxy material found in the cell walls of cork and similar plants …   Wiktionary

  • Suberin — Su|be|rin 〈n. 11〉 Korksubstanz [<lat. suber, Gen. suberis „Korkeiche“] * * * Su|be|rin, das; s, e [zu lat. suber = Kork] (Bot.): hochmolekulare Substanz, die als Stoffwechselprodukt der höheren Pflanzen in den Zellwänden des Kork bildenden… …   Universal-Lexikon

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