Search results
Results from the WOW.Com Content Network
A gametangium (pl.: gametangia) is a sex organ or cell in which gametes are produced that is found in many multicellular protists, algae, fungi, and the gametophytes of plants. In contrast to gametogenesis in animals , a gametangium is a haploid structure and formation of gametes does not involve meiosis .
Female gametophytes of the liverwort Marchantia polymorpha. Gametophores are prominent structures in seedless plants on which the reproductive organs are borne. [citation needed] [1] The word gametophore (more accurately gametangiophore) is composed of the greek ‘gamete-,’ referring (loosely) to gametangia [citation needed] and ‘-phore’ (Greek Φορά, "to be carried"). [2]
The female gametangia are called archegoniophores, they have a taller stem and an umbrella-like structure at the top, approximately 1 cm (0.39 in) wide, from which the common name is derived. They also reproduce asexually via gemma cups which form on the surface of the thallus, they are approx. 4 mm (0.16 in) wide and 3 mm (0.12 in) high. [ 2 ]
The result is a multi-cellular haploid organism, called the gametophyte (because it produces gametes at maturity). [17] When it reaches maturity, the gametophyte produces one or more gametangia (singular: gametangium) which are the organs that produce haploid gametes. At least one kind of gamete possesses some mechanism for reaching another ...
These organs resemble gametangia except that they contain only nuclei. A bridge, the trichogyne forms, that provides a passage for nuclei to travel from the antheridium to the ascogonium. A dikaryon grows from the ascogonium, and karyogamy occurs in the fruiting body.
Bryophytes have life cycles that are gametophyte dominated. The longer lived, more prominent autotrophic plant is the gametophyte. The sporophyte in mosses and liverworts consists of an unbranched stalk (a seta) bearing a single sporangium or spore-producing capsule. Even when capable of photosynthesis, as in mosses and hornworts, bryophyte ...
Discover the best free online games at AOL.com - Play board, card, casino, puzzle and many more online games while chatting with others in real-time.
Allomyces thalli consist of a cylindrical trunk-like basal cell that gives rise to well-developed, highly branched rhizoids that anchor the thallus to the substrate. The trunk-like basal cell also gives rise to numerous dichotomously branched side branches that terminate as either resistant sporangia, zoosporangia, or gametangia depending on the life cycle stage.