spirogyra

spirogyra
/spuy'reuh juy"reuh/, n. Bot.
a widely distributed filamentous freshwater green alga of the genus Spirogyra.
[1895-1900; < NL, equiv. to spiro- SPIRO-2 + -gyra, alter. of Gk gyros circle or gyrós round]

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 genus of green algae, found only in fresh water and usually free-floating. The slippery unbranched filaments are composed of cylindrical cells containing one or more beautiful spiral green chloroplasts, from which the genus gets its name. The nucleus is suspended in the central vacuole by fine cytoplasmic filaments. Vegetative reproduction is by fragmentation of the filaments. In sexual conjugation, cells of two strands lying side by side are joined by the outgrowths, or conjugation tubes, and the contents of one cell pass into and fuse with the contents of the other. The resulting fused cell (zygote) becomes surrounded by a thick wall and overwinters, while the vegetative filaments die.

      On bright spring or fall days, there might be masses of Spirogyra floating near the surface of streams and ponds, buoyed by oxygen bubbles released during photosynthesis. During the night, when photosynthesis decreases, the masses tend to sink.

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Universalium. 2010.

Look at other dictionaries:

  • Spirogyra — bei der Konjugation Systematik ohne Rang: Chloroplastida Abteilung …   Deutsch Wikipedia

  • Spirogyra — Жанр фолк рок, прогрессивный рок, прогрессивный фолк, Кентербери Годы с 1960 х по 1974 Стр …   Википедия

  • spirogyra — [spī΄rō jī′rə] n. [ModL < Gr speira,SPIRE1 + gyros, a ring: see GYRATE] any of a genus (Spirogyra, family Zygnemataceae) of freshwater green algae containing spiral chlorophyll bands in their cylindrical cells …   English World dictionary

  • Spirogyra —   [zu griechisch speĩra »Windung« und gỹros »Kreis«], die Algengattung Schraubenalge …   Universal-Lexikon

  • spirogyra — ► NOUN Botany ▪ algae of a genus found in blanket weed, consisting of long green filaments. ORIGIN from Greek speira coil + guros round …   English terms dictionary

  • Spirogyra — Spirogyre Spirogyre …   Wikipédia en Français

  • Spirogyra — Taxobox color = lightgreen name = Spirogyra image width = 250px domain = Eukaryote unranked regnum = Archaeplastida regnum = Plantae unranked phylum = Streptophyta phylum = Chlorophyta classis = Zygnematophyceae ordo = Zygnematales familia =… …   Wikipedia

  • Spirogyra —   Spirogyra …   Wikipedia Español

  • spirogyra — noun Etymology: New Latin, from Latin spira + Greek gyros ring, circle Date: 1875 any of a genus (Spirogyra) of freshwater green algae with spiral chloroplasts …   New Collegiate Dictionary

  • spirogyra — noun Any of a group of freshwater, filamentous green algae, of the genus Spirogyra, having chloroplasts arranged in spirals …   Wiktionary

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