Aleurone


Aleurone

Aleurone (from Greek "aleuron", flour) is a protein found in protein granules of maturing seeds and tubers. The term is also used for the outermost cell layer of the seed coat, the aleurone layer.

Aleurone protein

Aleurones can have two different morphological features, homogenous and heterogeneous. The homogenous aleurone consists of similar protein bodies (e.g. "Phaseolus vulgaris") while the heterogeneous aleurone consists of granules of different shapes and types of proteins covered with a membrane (e.g. "Ricinus communis").

Aleurone tissue

The aleurone layer surrounds the endosperm tissue of grass seeds. In the cultivated cereals it is usually single-layered (except in barley). In cereals with starchy endosperm, the aleurone contains about 30% of the kernel's proteins. In multicolored corn, anthocyanin pigments in the aleurone layer give the kernels a dark, bluish-black color.

During seed germination, the plant embryo produces the hormone gibberellin that triggers the aleurone cells to release enzymes for the hydrolysis of starch and storage proteins into the endosperm. The breakdown of the starchy endosperm supplies sugars to drive the growth of roots and the acrospire. This effect is inhibited by the plant hormone abscisic acid, which keeps the seed dormant.

The gibberellin effect on the aleurone is used in brewing, specifically in the production of barley malt where treatment ensures that a batch of barley seeds will germinate evenly.


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • aleurone — [ alørɔn ] n. f. • 1865; gr. aleuron « farine » ♦ Bot. Substance protéique de réserve des graines de nombreux spermaphytes. ⇒ légumine. ● aleurone nom féminin (grec aleuron, farine) Réserve alimentaire protidique des graines, contenue soit dans… …   Encyclopédie Universelle

  • Aleurone — A*leu rone, n. [Gr. ? flour.] (Bot.) An albuminoid substance which occurs in minute grains ( protein granules ) in maturing seeds and tubers; supposed to be a modification of protoplasm. [1913 Webster] …   The Collaborative International Dictionary of English

  • aleurone — /aleu rone/ s.m. [der. del gr. áleuron farina ]. (biochim.) [sostanza proteica presente nei semi di cereali] ▶◀ glutine …   Enciclopedia Italiana

  • aleurone — [al′yo͞o rōn΄, ə lo͞o′rōn΄] n. [Ger aleuron < Gr, wheat meal, flour < alleein, to grind < IE base * al > Arm alauri, a mill] finely granulated protein present in seeds generally and forming the outer layer of cereal seeds aleuronic… …   English World dictionary

  • Aleurone — Une partie des pigments de ces grains de maïs se trouvent dans leur couche à aleurone. L aleurone (terme venant du grec aleuron, farine) est une protéine présente sous formes de grains dans l albumen de nombreuses graines. Elle y forme l assise… …   Wikipédia en Français

  • aleurone — aleuronic /al yoo ron ik/, adj. /al yeuh rohn , euh loor ohn/, n. (in the seeds of cereal plants) protein granules (aleurone grains) found in a single layer of cells (aleurone layer) in the outermost portion of the endosperm. Also, aleuron /al… …   Universalium

  • aleurone — noun Etymology: German Aleuron, from Greek, flour; akin to Armenian ałam I grind Date: 1869 protein matter in the form of minute granules or grains occurring in seeds in endosperm or in a special peripheral layer …   New Collegiate Dictionary

  • aleurone — noun The protein content of the embryo, endosperm, or perisperm of cereals See Also: aleuronic …   Wiktionary

  • aleurone — al·eu·rone al yə .rōn n protein matter in the form of minute granules or grains occurring in seeds in endosperm or in a special peripheral layer al·eu·ron·ic .al yə rän ik adj * * * al·eu·rone (ə l rґōn) (alґyə rōn″)… …   Medical dictionary

  • aleurone — a·leu·ró·ne s.m. TS biochim. sostanza proteica immagazzinata nei semi delle piante come riserva nutritiva {{line}} {{/line}} DATA: 1955. ETIMO: der. di aleuro con 4 one …   Dizionario italiano