Gametophyte

Gametophyte
Several gametophytes growing in a terrarium.
Protonema of the moss Physcomitrella patens

A gametophyte is the haploid, multicellular phase of plants and algae that undergo alternation of generations, with each of its cells containing only a single set of chromosomes.

The gametophyte produces male or female gametes (or both), by a process of cell division called mitosis. The fusion of male and female gametes produces a diploid zygote, which develops by repeated mitotic cell divisions into a multicellular sporophyte. Because the sporophyte is the product of the fusion of two haploid gametes, its cells are diploid, containing two sets of chromosomes. The mature sporophyte produces spores by a process called meiosis, sometimes referred to as "reduction division" because the chromosome pairs are separated once again to form single sets. The spores are therefore once again haploid and develop into a haploid gametophyte.

In mosses, liverworts and hornworts (bryophytes), the gametophyte is the commonly known phase of the plant. An early developmental stage in the gametophyte of mosses (immediately following germination of the meiospore) is called the protonema. The adult gametophyte of mosses is called the gametophore as it carries the gamete-producing sex organs. [1]

In most other land plants, the gametophyte is very small. In ferns the gametophyte is a free living organism called the prothallus, in contrast to angiosperms.[2]

In gymnosperms and angiosperms, the gametophyte are reduced to only a few cells; in angiosperms the female gametophyte (sometimes called the "embryo sac") is known as a megagametophyte and the male gametophyte (pollen) is called a microgametophyte.

In some multicellular green algae, red algae, or brown algae (Ulva is one example), the sporophytes and gametophytes are often isomorphic, but in some species the gametophyte may be reduced.

References

  1. ^ Ralf Reski(1998): Development, genetics and molecular biology of mosses. In: Botanica Acta 111, pp 1-15.
  2. ^ C.Michael Hogan. 2010. Fern. Encyclopedia of Earth. National council for Science and the Environment. Washington, DC

See also



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Look at other dictionaries:

  • Gametophyte — Gamétophyte schéma du cycle reproductif des Embryophytes Le gamétophyte est la génération du cycle de vie qui produit les gamètes de la plante. En d autres termes, c est l individu issu d une méiospore et produisant des gamètes. Le gamétophyte n… …   Wikipédia en Français

  • gamétophyte — ● gamétophyte nom masculin Organisme végétal issu d une spore, destiné à former les gamètes et reconnaissable dans les espèces végétales où il existe une alternance des générations. gamétophyte n. m. BOT Individu haploïde, sexué ou hermaphrodite …   Encyclopédie Universelle

  • Gametophyte — Ga*me to*phyte, n. [Gamete + Gr. fyto n plant.] (Bot.) In the alternation of generations in plants, that generation or phase which bears sex organs and produces gametes. In the lower plants, as the alg[ae], the gametophyte is the conspicuous part …   The Collaborative International Dictionary of English

  • gametophyte — gametophyte. См. гаметофит. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • gametophyte — [gə mēt′əfīt΄] n. in plants, the gamete bearing generation that is haploid and reproduces by eggs and sperms: distinguished from SPOROPHYTE gametophytic [gə mēt′əfit′ik] adj …   English World dictionary

  • Gamétophyte — schéma du cycle reproductif des Embryophytes Le gamétophyte est la génération du cycle de vie qui produit les gamètes de la plante. En d autres termes, c est l individu issu d une méiospore et produisant des gamètes. Le gamétophyte n est pas… …   Wikipédia en Français

  • gametophyte — gametophytic /geuh mee teuh fit ik, gam i /, adj. /geuh mee teuh fuyt , gam i /, n. Bot. the sexual form of a plant in the alternation of generations. Cf. sporophyte. [1890 95; GAMETO + PHYTE] * * * In certain plants, the sexual phase (or an… …   Universalium

  • gametophyte — The phase of the plant life cycle that carries the gamete producing organs. In flowering plants, the pollen grain is the male gametophyte and the embryo sac is the female gametophyte …   Glossary of Biotechnology

  • gametophyte — gametofitas statusas T sritis augalininkystė apibrėžtis Lytinė žiedinių augalų karta, turinti perpus mažesnį (haploidinį) chromosomų skaičių negu sporofitas. atitikmenys: angl. gametophyte rus. гаметофит; половое поколение ryšiai: sinonimas –… …   Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

  • gametophyte incompatibility — gametofitinis nesuderinamumas statusas T sritis augalininkystė apibrėžtis Nesuderinamumas, lemiamas alelinių genų (S), tarp kurių nėra dominavimo sąveikos. Taip būna, kai liemenėlis ir žiedadulkė turi tokius pat alelius ir dėl to slopinamas… …   Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

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