Navicula (genus)
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Navicula is a genus of diatoms (Bacillariophyta) and comprises around 250 species. Navicula is the diminutive of the Latin navis and means "little boat".
features
The representatives are small, boat-shaped, unicellular algae . The bowls are rectangular when viewed from the side; when viewed from the side, they are boat-shaped. A cell contains two plastids with no pyrenoids . They are elongated and golden brown in color due to the fucoxanthin . The plastids lie against the belt ligaments. Some species have H-shaped plastids. The edge of the plastids is always smooth. The nucleus is in the middle of the cell. The two shells have a clearly pronounced raphe in the middle. The shell is finely structured, in the center there is a round area without structures. The cells are capable of rapid creeping movements over the substrate. The size ranges from 5 to 70 microns.
Asexual reproduction occurs through the typical dichotomy of diatoms. Sexual reproduction occurs through isogamy, with one gamete being formed per cell. After the cells fuse, an auxospore is formed and the cells expand.
The species differ in cell shape, cell size, shell features and the shape of the plastids.
Occurrence
Navicula occur on the substrate in all types of water.
supporting documents
- Karl-Heinz Linne von Berg, Michael Melkonian u. a .: The Kosmos algae guide. The most important freshwater algae under the microscope. Kosmos, Stuttgart 2004, ISBN 3-440-09719-6 , p. 222.
