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Antheridia consist of a thin cellular layer that holds many sperm inside. Here, the diagram of a liverwort antheridium is shown. An antheridium is a haploid structure or organ producing and containing male gametes (called antherozoids or sperm). The plural form is antheridia, and a structure containing one or more antheridia is called an ...
The antheridia (male reproductive structure) are at the apex of the male gametophyte in a cup-like structure formed by perigonial leaves which are modified stem leaves. [11] Sperm is produced in the antheridia via mitosis, and when mature they are released from the antheridia by raindrops splashing onto the cup. Sperm can be dispersed up to one ...
The biflagellate sperm must swim from the antheridia, or else be splashed to the archegonia. When this happens, the sperm and egg cell fuse to form a zygote, the cell from which the sporophyte stage of the life cycle will develop. Unlike all other bryophytes, the first cell division of the zygote is longitudinal. Further divisions produce three ...
Oogonial cells may exist in a series along the filament, and so division may also occur in a series; resulting in each oogonium containing a single egg. [19] Production of an egg causes swelling of the cell wall. Antheridia are short and disk-shaped, containing 1 to 2 multi-flagellated sperm cells.
Diagram of archegonium anatomy. An archegonium (pl.: archegonia), from the Ancient Greek ἀρχή ("beginning") and γόνος ("offspring"), is a multicellular structure or organ of the gametophyte phase of certain plants, producing and containing the ovum or female gamete.
The sporophyte of many liverworts are non-photosynthetic, but there are also several that are photosynthetic to various degrees. [14] Cells in a typical liverwort plant each contain only a single set of genetic information, so the plant's cells are haploid for the majority of its life cycle. This contrasts sharply with the pattern exhibited by ...
The green cells contain chloroplasts. Another characteristic feature of the genus is its parallel photosynthetic lamellae on the upper surfaces of the leaves. The leaves of most mosses are simply a single plate of cells, but those of Polytrichum have more highly differentiated photosynthetic tissue. This is an example of a xeromorphic adaption ...
Plants are usually monoicous, and sexual reproduction is by antheridia and archegonia. Asexual reproduction occurs by spores, by fragmentation of the rosettes, and by formation of apical tubers. Spores are large (45 to 200 μ) and formed in tetrads. [2] The sporophyte of Riccia is the simplest amongst bryophytes. It consist of only a capsule ...