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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]
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 .
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 ]
Vegetative incompatibility within species often prevents a fungal isolate from mating with another isolate. Isolates of the same incompatibility group do not mate or mating does not lead to successful offspring. High variation has been reported including same-chemotype mating, sporophyte to gametophyte mating and biparental transfer of ...
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 ...
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.
[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 tiny gametophyte develops inside the wall of a microspore, producing a pollen grain. Pollen grains can be physically transferred between plants by the wind or animals, most commonly insects . Pollen grains can also transfer to an ovule of the same plant, either with the same flower or between two flowers of the same plant ( self-fertilization ).