Pinnularia

Pinnularia viridis

Pinnularia is a genus of diatoms ( Bacillariophyta ) with about 200 species of freshwater and occur in seawater.

Features

The representatives are unicellular, small to very large diatoms. The individual cells have the typical diatom shell of two counters. The tray is rectangular in side view, in valve view it is long - elliptical with blunt end. Both shells have in the middle of a pronounced raphe. The cells can crawl with their help over the substrate. At the edge of the shell marked ribs sit approximately in the direction of the longitudinal axis. They have two elongated plastids of golden brown color and without pyrenoids. They are located along the belt straps. Only two species each have a conspicuous pyrenoid per plastid. Some species have a single H-shaped plastids. The cells are 20 to 300 micrometers long.

Asexual reproduction occurs by the typical dichotomy of diatoms. Sexual reproduction takes place by Anisogamie, with one or two per cell gametes are formed. Following Auxosporenbildung during the cell enlargement takes place. In the genus was also apogamy, the formation zygotenähnlicher stages without Gametenverschmelzung observed.

Occurrence

Pinnularia lives in the benthos of oligo - or mesotrophic waters.

Documents

• K.-H. Linne von Berg, K. Hoef -Emden, B. Marin, M. Melkonian: The Cosmos algae leader. The main freshwater algae under the microscope. Kosmos, Stuttgart 2004, pp. 226, ISBN 3-440-09719-6