/stoh"mayt/, n.
stoma (def. 1).
[perh. by back formation from STOMATA, based on an assumed NL sing. *stomatum; see -ATE1]

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▪ plant anatomy
also called  Stoma,  plural  Stomata, or Stomas,  
 any of the microscopic openings or pores in the epidermis of leaves and young stems. Stomates are generally more numerous on the underside of leaves. They provide for the exchange of gases between the outside air and the branched system of interconnecting air canals within the leaf.

      A stomate opens and closes in response to the internal pressure of two sausage-shaped guard cells that surround it. The inner wall of a guard cell is thicker than the outer wall. When the guard cell is filled with water and it becomes turgid, the outer wall balloons outward, drawing the inner wall with it and causing the stomate to enlarge.

      Guard cells work to control excessive water loss, closing on hot, dry, or windy days and opening when conditions are more favourable for gas exchange. At dawn a sudden increase in stomatal opening, reaching maximum near noon, is followed by a decline because of water loss. Recovery and reopening are then followed by another decline as darkness approaches.

      The concentration of carbon dioxide in the air is another regulator of stomatal opening in many plants. When carbon dioxide levels fall below normal (about 0.03 percent), the guard cells become turgid and the stomata enlarge.

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Universalium. 2010.

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  • stomate — [ stɔmat ] n. m. • 1817; nom d un mollusque 1803; du gr. stoma « bouche » ♦ Bot. Ouverture naturelle sur l épiderme de la tige ou de la feuille, qui assure des échanges gazeux avec le milieu extérieur (respiration, excrétion). ⇒ pore. L épicéa «… …   Encyclopédie Universelle

  • Stomate — ouvert (2900x) Stomate ouvert (350x) Un stomate est un orifice de petite tail …   Wikipédia en Français

  • Stomate — Sto mate, n. (Bot.) A stoma. [1913 Webster] …   The Collaborative International Dictionary of English

  • stomate — noun Etymology: irregular from New Latin stomat , stoma Date: 1835 stoma 2 …   New Collegiate Dictionary

  • STOMATE — n. m. T. de Botanique Petit orifice qui sert à la respiration des végétaux …   Dictionnaire de l'Academie Francaise, 8eme edition (1935)

  • stomate — adj. [Gr. stoma, mouth] 1. Bearing a mouth. 2. (ANNELIDA) A nephridium with a funnel; an open nephridium …   Dictionary of invertebrate zoology

  • stomate — noun stoma …   Wiktionary

  • stomate — (sto ma t ) s. m. Terme de botanique. Pore microscopique qui se voit dans l épiderme des plantes. Les stomates servent uniquement à la respiration des végétaux. ÉTYMOLOGIE    Du grec, bouche, orifice …   Dictionnaire de la Langue Française d'Émile Littré

  • stomate — [ stəʊmeɪt] noun Botany another term for stoma. Derivatives stomatal adjective Origin C19: appar. an Engl. singular of stomata …   English new terms dictionary

  • -stomate — sto·mate …   English syllables

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