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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]
[1] [2] Both monoicous (/ m ɒ ˈ n oʊ ə k ə s /) [3] and dioicous gametophytes produce gametes in gametangia by mitosis rather than meiosis, so that sperm and eggs are genetically identical with their parent gametophyte. It has been suggested that monoicy may have benefits in dry habitats where the ability to produce sporophytes is limited ...
A gametophyte (/ ɡ ə ˈ m iː t ə f aɪ t /) is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the sexual phase in the life cycle of plants and algae.
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 ]
[9] and Wagner and Mitchell. [10] After fusion of the cells, the further fusion of their nuclei is delayed. Instead, a nucleus from the fertilizing cell and a nucleus from the ascogonium become associated and begin to divide synchronously. The products of these nuclear divisions (still in pairs of unlike mating type, i.e.
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 ...
Antheridia are present in the gametophyte phase of cryptogams like bryophytes and ferns. [2] Many algae and some fungi , for example, ascomycetes and water moulds , also have antheridia during their reproductive stages.