Haematococcus
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Aplanospores of Haematococcus pluvialis |
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| Haematococcus | ||||||||||||
| Flot. emend. will |
Haematococcus is an algae - genus from the class of Chlorophyceae .
description
Haematococcus lives as a single cell with two very different manifestations.
Under favorable conditions, the alga lives as a green flagellate with a thick, swollen cell wall and two flagella of equal length . The cell body is elliptical to pear-shaped with cytoplasmic threads that run radially in the hyaline (glassy) cell wall. A gelatinous layer separates the cell body from the cell wall. The chloroplast is cup-shaped with several pyrenoids , a triangular pale eye-spot and several contractile vacuoles in the cell periphery. The cells reach a length of 26 to 70 µm.
Under unfavorable conditions, the cells are transformed into thick-walled, unglued and red-colored permanent stages, the so-called aplanospores . The red color comes from a carotenoid, astaxanthin , which protects the dry cells from damage to the DNA caused by UV radiation. Astaxanthin is mainly found in green algae .
Reproduction
During asexual reproduction , after the protoplast has divided, four or eight zoospores form , which leave the mother cell wall. The red aplanospores can either release green zoospores or form aplanospores again.
The sexual reproduction is done by isogamy . By multiple division of the protoplasts 16 or 32 small, spindle-shaped and flagellated gametes are formed. After the gamete fusion, a thick-walled zygote is formed .
Types (selection)
- Haematococcus allmanii
- Haematococcus carocellus
- Haematococcus lacustris
- Haematococcus pluvialis
- Haematococcus zimbabwiensis
distribution
Haematococcus lives mainly in small bodies of water that dry out quickly and are only filled sporadically by rain.
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 .
