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Nostoc with hormogonia. Hormogonia are motile filaments of cells formed by some cyanobacteria in the order Nostocales and Stigonematales.They are formed during vegetative reproduction in unicellular, filamentous cyanobacteria, and some may contain heterocysts and akinetes.
Many cyanobacteria form motile filaments of cells, called hormogonia, that travel away from the main biomass to bud and form new colonies elsewhere. [45] [46] The cells in a hormogonium are often thinner than in the vegetative state, and the cells on either end of the motile chain may be tapered. To break away from the parent colony, a ...
Heterocysts or heterocytes are specialized nitrogen-fixing cells formed during nitrogen starvation by some filamentous cyanobacteria, such as Nostoc, Cylindrospermum, and Anabaena. [1] They fix nitrogen from dinitrogen (N 2) in the air using the enzyme nitrogenase, in order to provide the cells in the filament with nitrogen for biosynthesis. [2]
Many cyanobacteria form motile filaments of cells, called hormogonia, that travel away from the main biomass to bud and form new colonies elsewhere. [56] [57] The cells in a hormogonium are often thinner than in the vegetative state, and the cells on either end of the motile chain may be tapered. To break away from the parent colony, a ...
Usually the filament breaks into a number of fragments called hormogonia. Each hormogonium consist of one or more cells and grows into a filament by cell division in one direction. [1] As a result of recent genetic analyses, several new genera were erected from this genus, e.g. Tenebriella. [3]
Each trichome has a narrow aptic portion which is whip- or tail-like consisting of a row of small cells. Akinetes are absent in Rivularia . The species multiply with the aid of hormogonia and heterocyst.
Nostoc, also known as star jelly, troll's butter, spit of moon, fallen star, witch's butter (not to be confused with the fungi commonly known as witches' butter), and witch's jelly, is the most common genus of cyanobacteria found in a variety of both aquatic and terrestrial environments that may form colonies composed of filaments of moniliform cells in a gelatinous sheath of polysaccharides. [1]
Members of the cyanobacterial genus Nostoc can become motile through the use of hormogonia, while the host plant excretes chemicals to guide the cyanobacteria via chemotaxis. [33] For instance, liverworts in the genus Blasia can secrete HIF, a strong chemo-attractant for nitrogen-starved and symbiotic cyanobacteria.