Desmids are an order (Desmidiales) of green algae,[1] comprising around 40 genera and 5,000[2] to 6,000[3] species, found mostly but not exclusively in fresh water. Most are unicellular, and are 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 may be united as the division Gamophyta. The desmids are sometimes treated as members of the Zygnematales, but more often given the separate order Desmidiale
Desmids possess characteristic crystals of Barium sulphate at either end of the cell[5] which exhibit a continuous Brownian type motion.
References
- ↑ 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.
- ↑ 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
- ↑ Brook, Alan J., 1981. The Biology of Desmids, page 1. (Berkeley: University of California Press). ISBN 0-520-04281-6
- ↑ 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.
- ↑ Proceedings of the Royal Society -Biological Minerals Formed from Strontium and Barium Sulphates. II. Crystallography and Control of Mineral Morphology in Desmids
External links
Further reading
- 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
