Tychonema
| Generic name: TYCHONEMA Anagnostidis et Komárek, 1988. Algolog. Stud. 50-53: 410. | ||||||||||
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| Type species: Tychonema tenue (Skuja) Anagnostidis et Komarek 1988. - , originally described as Oscillatoria. | ||||||||||
| Descriptions: Komárek (1992): Filamentous; filaments solitary, free floating or coiled in clusters or fine strata, planktic, tychoplanktic, benthic or metaphytic, straight, arcuated or freely irregularly coiled, many-celled, up to 5 mm long, isopolar, without sheaths or facultatively with very fine and indistinct mucilaginous enveloping layers. Trichomes cylindrical, isopolar, not attenuated to the ends, unconstricted (or indistinctly constricted) at the cross walls, more or less isodiametric or slightly longer or shorter than wide, with thin cell walls, 2-16 um wide, without any branching, without or with reduced motility; end cell 5 rounded, usually with thickened outer cell wall or with narrow calyptra. Cells mostly cylindrical, pale blue-green, yellowish or reddish, always without gas vesicles, but sometimes intensely vacuolated during prominent phases of vegetation cycles and with keritomized chromatoplasma (special location of thylakoids combined with vacuolization). Changeable phycobilin pigments ratio, usually with higher content of phycoerythrin. Heterocytes and akinetes absent. |
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| Genotype differences, molecular data: | ||||||||||
| Reproduction strategies, life cycles, cell division: Komárek (1992): Cells divide by symmetric binary fission with very different division frequencies on a trichome and during the vegetation phase; all cells capable to divide. Reproduction by fragmentation of trichomes into non-motile hormocytes. |
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| Ultrastructure: | ||||||||||
| Taxonomic position, higher hierarchy: Cyanophyceae, Oscillatoriales, Phormidiaceae, Phormidioideae Notes to taxonomy, misinterpretations: |
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| Ecology, ecophysiology, ecological significance: Komárek (1992): Planktic, tychoplanktic or benthic species, known mainly from North-European, oligotrophic, mesotrophic or slightly eutrophic water reservoirs. Probably mainly cold-stenotherm species, distributed in colder parts of temperate zone. |
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| Physiology and biochemistry: |
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| Distribution, endemism, problematic citations: |
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| Infrageneric scheme, species concept: |
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| List of species: Tychonema bornetii (Zukal) (Skuja) Anagnostidis et Komárek 1988 Tychonema bourrellyi (Lund) (Skuja) Anagnostidis et Komárek 1988 Tychonema sequanum (Couté) Anagnostidis et Komárek 1988 Tychonema tenue (Skuja) Anagnostidis et Komárek 1988 Unclear taxa: Oscillatoria ucrainica Vladimirova 1961 Phormidium heteropolare Skuja 1964 Tychonema bornetii var. intermedia Voronichin 1930 Tychonema decoloratum (G.S.West) Anagnostidis et Komárek 1988 Tychonema exospirum (Skuja) Anagnostidis et Komárek 1988 Tychonema rhodonema (Skuja) Anagnostidis et Komárek 1988 |
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Drawings: Komárek 1992 |
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Literature:
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