water network
| water network | ||||||||||||
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H. reticulatum , detail |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Hydrodictyon | ||||||||||||
| Roth (1797) |
The green algae of the genus Hydrodictyon (from gr. Hydor = water and gr. Diktyon = net) bear the common name water net because of their unusual growth form : most of the cells are connected at their ends with two neighbors; together they form a net-like structure of pentagons and hexagons. The (often tubular) nets can reach a size of several decimeters, whereby the individual cells can be up to 1 cm long. Since each mesh of the network consists of 3 to 9 (mostly 6) cells, the meshes are easy to see with the naked eye. Their color is a fresh light green, which contributes a lot to the appealing exterior. The formation of the networks was first described by Jean-Pierre Vaucher .
Occurrence
Water networks occur in the temperate and subtropical zones of Eurasia in stagnant or slowly flowing waters with clean water, which can, however, show a certain degree of eutrophication .
Reproduction
As with most green algae , the life cycle of Hydrodictyon includes a generation change : In asexual reproduction , new plants grow from zoospores . These can either grow together within the mother cell to form a new, reticulated colony , which eventually becomes independent when the mother cell dissolves, or zoospores released into the water can grow into thick-walled polygonal polyhedra , which later become spherical nets. Because every cell in a colony is able to develop a daughter colony inside, the water network can reproduce asexually very quickly.
Sexual reproduction takes place via isogametes , which after merging to form a hypno zygote form four zoospores that can grow into new colonies.
species
More than 40 species are known:
- Hydrodictyon africanum Yamanouchi
- Hydrodictyon granulatum Biasoletto
- Hydrodictyon indicum
- Hydrodictyon majus Roth
- Hydrodictyon patenaeforme Pocock
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Hydrodictyon reticulatum ( Linnaeus ) Bory de Saint-Vincent
- H. reticulatum var. Nodosum Playfair
- H. reticulatum var. Minimum Playfair
- H. reticulatum var. Bernardii Playfair
- Hydrodictyon utriculatum Roth
- Hydrodictyon pentagonum Vaucher
Water networks and man
Some countries are entrained Hydrodictyon - species as Invasive species ( neophytes problematic), such. B. Hydrodictyon reticulatum in New Zealand .
Some aquarists use H. reticulatum as an aquarium plant in aquariums with algae-eating freshwater shrimp .
literature
- H. Carter-Lund: Fresh Water Algae . Biopress Ltd, Bristol 1995.
- B. Fott: algae customer . Fischer Verlag, Stuttgart 1971.
- Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 (reprint from 1996).
- Andre Pirson, Ursula Kaiser: Sexual reproduction of the green alga Hydrodictyon reticulatum . Publication accompanying the film by the IWF , Göttingen 1970.
- Andre Pirson, Ursula Kaiser: Asexual reproduction of the green alga Hydrodictyon reticulatum . Publication accompanying the film by the IWF , Göttingen 1970
- Strasburger: Textbook of botany . Any edition.
- Hydrodictyon ROTH (English) on The SilicaSecchiDisk of Connecticut College
- Algae base
Web links
- Water network at www.algaebase.org (English)