Desmidiales

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Desmids
Micrasterias furcata
Scientific classification
Class: Zygnemophyceae
Order: Desmidiales
Families

Closteriaceae
Desmidiaceae
Gonatozygaceae
Peniaceae

Desmids are an order (Desmidiales) in the Charophyta, a division of green algae that forms a sister group to the land plants (Embryophyta).[1] The Desmidiales comprise around 40 genera and 5,000[2] to 6,000[3] species, found mostly but not exclusively in fresh water. Most are unicellular, the cell sometimes divided into two compartments separated by a narrow bridge or isthmus. Desmids assume a variety of highly symmetrical and generally attractive shapes, which provide the basis for their classification. Each compartment has one chloroplast, and no flagella. Sexual reproduction occurs through a process of conjugation,[4] also found among the Zygnematales. These two groups are closely related, and comprise the class Zygnematophyceae. The desmids are sometimes treated as members of the Zygnematales,[citation needed] but more often given the separate order Desmidiales.

Desmids possess characteristic crystals of Barium sulphate at either end of the cell[5] which exhibit a continuous Brownian type motion.

References[edit]

  1. ^ Gontcharov AA, Marin BA, Melkonian MA (January 2003). "Molecular phylogeny of conjugating green algae (Zygnemophyceae, Streptophyta) inferred from SSU rDNA sequence comparisons". J. Mol. Evol. 56 (1): 89–104. doi:10.1007/s00239-002-2383-4. PMID 12569426. 
  2. ^ Van den Hoek, C., D. G. Mann, & H. M. Jahns, 1995. Algae:An Introduction to Phycology, page 468. (Cambridge: Cambridge University Press). ISBN 0-521-30419-9
  3. ^ Brook, Alan J., 1981. The Biology of Desmids, page 1. (Berkeley: University of California Press). ISBN 0-520-04281-6
  4. ^ Kapraun DF (April 2007). "Nuclear DNA content estimates in green algal lineages: chlorophyta and streptophyta". Ann. Bot. 99 (4): 677–701. doi:10.1093/aob/mcl294. PMC 2802934. PMID 17272304. 
  5. ^ Proceedings of the Royal Society -Biological Minerals Formed from Strontium and Barium Sulphates. II. Crystallography and Control of Mineral Morphology in Desmids

External links[edit]

Further reading[edit]

  • Survey of Clare Island 1990 - 2005, noting the Desmidiales recorded. Ed. Guiry, M.D., John, D.M., Rindi, F. and McCarthy, T.K. 2007. New Survey of Clare Island. Volume 6: The Freshwater and Terrestrial Algae. Royal Irish Academy. ISBN 978-1-904890-31-7