Pinnularia
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| Ehrenberg |
Pinnularia is a genus of diatoms (Bacillariophyta) with around 200 species, of which occur in freshwater and in seawater.
features
The representatives are single-celled, small to very large diatoms. The individual cells have the typical diatom shell consisting of two counters. The shell is rectangular when viewed from the side, and long-elliptical when viewed from the shell with a blunt end. Both shells have a pronounced raphe in the middle . With their help, the cells can crawl across the substrate. On the edge of the bowl there are clear ribs roughly in the direction of the longitudinal axis. They have two elongated plastids of golden brown color and without pyrenoids . They are on the belt straps. Only two species each have a conspicuous pyrenoid per plastid. Individual species have a single H-shaped plastid. The cells are 20 to 300 micrometers long.
Asexual reproduction occurs through the typical dichotomy of diatoms. Sexual reproduction occurs through anisogamy , with one or two gametes being formed per cell . The cells then enlarge during the auxospore formation. Apogamy , the formation of zygote-like stages without gamete fusion, has also been observed in the genus .
Occurrence
Pinnularia lives in the benthos of oligo- or mesotrophic waters.
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. 226.
