stoma

stoma
stomal, adj.
/stoh"meuh/, n., pl. stomata /stoh"meuh teuh, stom"euh-, stoh mah"teuh/, stomas.
1. Also, stomate. Bot. any of various small apertures, esp. one of the minute orifices or slits in the epidermis of leaves, stems, etc., through which gases are exchanged.
2. Zool. a mouth or ingestive opening, esp. when in the form of a small or simple aperture.
3. Med. an artificial opening between two hollow organs or between one hollow organ and the outside of the body, constructed to permit the passage of body fluids or waste products.
[1675-85; < NL < Gk stóma mouth]

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Any of the microscopic openings or pores in the epidermis of leaves and young stems.

They are generally more numerous on the undersides of leaves. They provide for the exchange of gases between the outside air and the interconnecting air canals within the leaf. A stoma opens and closes in response to turgor pressure within its two surrounding guard cells. Because the inner wall of each of these sausage-or bean-shaped cells is thicker than the outer wall, when they fill with water and become turgid they balloon outward, enlarging the stoma. A drop in carbon-dioxide levels to lower than normal also causes the guard cells to become turgid. Guard cells control excessive water loss from the plant, closing on hot, dry, or windy days and opening when conditions are more favorable.

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Universalium. 2010.

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Synonyms:
(in plants), , / (in articulate animals)


Look at other dictionaries:

  • stoma — v. stomato . Trimis de LauraGellner, 13.09.2007. Sursa: DN  STÓMA s.f. (biol.; anat.) Orificiu, por sau deschidere mică pe suprafaţa unui organ. [< germ. Stoma, cf. gr. stoma]. Trimis …   Dicționar Român

  • stomă — stómă, stóme, s.f. (reg.) vas mare de pământ cu două toarte, în care se păstrează untură, miere, cereale, murături etc. Trimis de blaurb, 18.01.2007. Sursa: DAR  STÓMĂ s. f. (biol., anat.) orificiu, por, deschidere mică pe suprafaţa unui organ.… …   Dicționar Român

  • -stoma — (o, meno com., stomo) [dal gr. stóma bocca ]. Secondo elemento, atono, di parole composte del linguaggio scient. (come amblistoma, nefrostoma, ecc.), nelle quali significa bocca o più genericam. apertura …   Enciclopedia Italiana

  • stoma — orifice, small opening in an animal body, 1680s, Modern Latin, from Gk. stoma (gen. stomatos) mouth, from PIE root *stom en , denoting various body parts and orifices (Cf. Avestan staman mouth (of a dog), Hittite shtamar mouth, M.Bret. staffn… …   Etymology dictionary

  • Stoma — Sto ma, n.; pl. {Stomata}. [NL., fr. Gr. ?, ?, a mouth.] 1. (Anat.) One of the minute apertures between the cells in many serous membranes. [1913 Webster] 2. (Bot.) (a) The minute breathing pores of leaves or other organs opening into the… …   The Collaborative International Dictionary of English

  • Stoma — (gr.), 1) der Mund; 2) Mündung …   Pierer's Universal-Lexikon

  • Stoma — (griech.), Mund, Mündung, bei Pflanzen Spaltöffnung …   Meyers Großes Konversations-Lexikon

  • Stoma — (grch., Mehrzahl Stomăta), Mund, Mündung (s. Spaltöffnungen) …   Kleines Konversations-Lexikon

  • Stoma — Stoma, griech., Mund, Mündung; Stomalgie, Mundkrankheit; Stomatitis, Entzündung der Mundhöhle; Stomatorrhagie, Blutung aus der Mundhöhle …   Herders Conversations-Lexikon

  • stōma- — *stōma , *stōmaz, *stōmja , *stōmjaz? germ., Adjektiv: nhd. sanft, ruhig; ne. tender, quiet (Adjektiv); Rekontruktionsbasis: mnd., ahd.; Etymologie: vergleiche idg. *stā , *stə …   Germanisches Wörterbuch

  • stoma — ► NOUN (pl. stomas or stomata) 1) Botany a minute pore in the epidermis of the leaf or stem of a plant, allowing movement of gases in and out. 2) Zoology a small mouth like opening in some lower animals. 3) Medicine an artificial opening made… …   English terms dictionary

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