Netrium

from Wikipedia, the free encyclopedia
Netrium
Netrium oblongum var. Cylindricum

Netrium oblongum var. Cylindricum

Systematics
without rank: Chloroplastida
without rank: Charophyta
Class : Ornamental algae (Zygnemophyceae)
Order : Yoke algae (Zygnematales)
Family : Mesotaeniaceae
Genre : Netrium
Scientific name
Netrium
( Nägeli ) Itzigs. & Rothe

Netrium is a genus of algae from the group of yoke algae (Zygnematales).

features

The representatives are unicellular, uncultivated algae. The cells are somewhat elongated, usually two to five times as long as they are wide and from elliptical to spindle-shaped-cylindrical shape. The cells have a round cross-section and do not have a central constriction (sinus). There are two, rarely four, axial chloroplasts each with one (rarely two) pyrenoids . When viewed from the side, the chloroplasts show around six serrated longitudinal ridges; when viewed from the apical point, they appear accordingly star-shaped. Cell wall ornaments do not occur.

Asexual reproduction takes place through the dichotomy characteristic of the Zygnematales. Sexual reproduction occurs through the conjugation of two cells. The cell envelopes of the gametangia usually adhere to the zygote . The zygote germinates with reduction division .

The size of the cells ranges from 50 to 400 micrometers depending on the type.

distribution

The genus is widespread worldwide ( cosmopolitan ). Their representatives occur mainly in the benthos of raised bogs , but also in other acidic, oligotrophic waters.

Representative

The genus includes five species:

  • Netrium digitus has a haploid chromosome set of 592 chromosomes
  • Netrium interruptum
  • Netrium naegelii
  • Netrium oblongum
  • Netrium pseudactinotaenium

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. 116.

Individual evidence

  1. ↑ algaebase , accessed on August 21, 2008.
  2. ^ Closterium on algaebase.org , accessed August 21, 2008.
  3. ↑ Heinz Streble , Dieter Krauter : Life in the water drop. Microflora and microfauna of freshwater. An identification book. 10th edition. Kosmos, Stuttgart 2006, ISBN 3-440-10807-4 , p. 198.

Web links