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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]
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.
[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 ...
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Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes.Depending on the biological life cycle of the organism, gametogenesis occurs by meiotic division of diploid gametocytes into various gametes, or by mitosis.
Dioicy promotes outcrossing. [3] Sexual dimorphism is commonly found in dioicous species. [4]: 71 [2]: 378 Dioicy is correlated with reduced sporophyte production, [5] due to spatial separation of male and female colonies, scarcity or absence of males.
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 ).