Vaucheria
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Vaucheria sp., Thallus thread with reproductive organs |
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| Vaucheria | ||||||||||||
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Vaucheria is a genus of yellow-green algae (Xanthophyceae).
description
Vaucheria forms branched filaments with no transverse wall and a diameter of 10 to 200 µm with numerous plastids and cell nuclei . Inside the thread there is a large vacuole (siphonal organization of the thallus ). Transverse walls are only formed during multiplication. In contrast to green algae, there is no starch formation; reserve carbohydrates are stored outside the plastids in the cytoplasm . The threads are often anchored with rhizoids on or in the substrate.
The alga is sometimes attacked by the rotifer Proales werneckii . The infestation triggers the formation of pointed galls .
Multiplication
In Vaucheria, reproduction takes place both asexually and sexually.
Asexual reproduction
During vegetative reproduction, synzoospores form at the thread ends. These are 100 µm spherical structures made up of many flagellated cells . The spores then grow into new threads. This form of asexual reproduction is only known from Vaucheria .
Sexual reproduction
During sexual reproduction, small male sex cells fuse with large egg cells. Male and female sexual organs are formed adjacent to one another on the same thread. Since the reduction division only takes place during gamete formation , Vaucheria is a Diplonten (living being with a double set of chromosomes ).
Types (selection)
distribution
Vaucheria lives in flowing and standing fresh water , in periodically dry places as well as in damp locations remote from water such as forest paths. About 30% of the species are salt-loving and can be found mainly on muddy surfaces in the area of the estuaries .
swell
- 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 .
- Heinz Streble , Dieter Krauter : Life in a drop of water. Microflora and microfauna of freshwater. An identification book. 10th edition. Kosmos, Stuttgart 2006, ISBN 3-440-10807-4 .
