Pediastrum duplex explained

Pediastrum duplex is a species of fresh water green algae in the genus Pediastrum. It is the type species of the genus Pediastrum.^[1]

Pediastrum duplex forms nonmotile coenobia (colonies) with a fixed number of cells. These coenobia are flat and have a circular shape. The colonies usually contain 8 to 32 cells, with examples of 4, 64 or 128 occurring rarely.^[2] Colonies have holes between the cells; the holes are smaller in diameter than the cells. The cells are polygonal, distinctly rectangular in outline with concave sides. The outer cells of the coenobium have two triangular lobes that are longer than the cell body. At the tip of the lobes are very short rosettes that may also have fine bristles. The cell wall is usually smooth, but may sometimes have a distinct sculptured texture.^[3] It reproduces by forming autocolonies asexually, although sexual reproduction has also been observed.^[4]

Pediastrum duplex is a very common component of the freshwater phytoplankton, and has a cosmopolitan distribution. Because the cell wall is resistant to decay, the cell wall has been found in Holocene lake sediments.^[3]

Infraspecies

Because Pediastrum duplex is very variable, many infraspecific taxa have been named. A partial list is included below:

Pediastrum duplex brachylobum
Pediastrum duplex clathratum
Pediastrum duplex cohaerens
Pediastrum duplex duplex
Pediastrum duplex f. denticulatum Isabella & R.J. Patel
Pediastrum duplex gracillimum
Pediastrum duplex regulosum
Pediastrum duplex reticulatum
Pediastrum duplex rotundatum
Pediastrum duplex var. asperum
Pediastrum duplex var. clathratum (A.Braun) Lagerheim, 1882
Pediastrum duplex var. convexum W. Krieger
Pediastrum duplex var. cornutum
Pediastrum duplex var. gracillimum W. West & G.S. West
Pediastrum duplex var. irregulare G.R. Hegde & K. Somanna
Pediastrum duplex var. longicorne W. Krieger
Pediastrum duplex var. reticulatum Lagerheim, 1882
Pediastrum duplex var. rugulosum Raciborski
Pediastrum duplex var. subgranulatum Raciborski^{[5] [6]}

One variety, Pediastrum duplex var. gracillimum, has been shown to be not closely related to Pediastrum duplex sensu stricto. It differs by having cells with narrower lobes and comparatively larger gaps between cells in the colonies.^[3] This variety has been split off as a new genus, named Lacunastrum with Lacunastrum gracillimum as its sole species.^[7]

Further reading

• Cao, X., Strojsová, A., Znachor, P. & Zapomelová, E. (2005). Detection of extracellular phosphatases in natural spring phytoplankton of a shallow eutrophic lake (Donghu, China). European Journal of Phycology 40: 251–258.
• Day, S.A., Wickham, R.P., Entwisle, T.J. & Tyler, P.A. (1995). Bibliographic check-list of non-marine algae in Australia. Flora of Australia Supplementary Series 4: vii + 276.
• Hu, H. & Wei, Y. (2006). The freshwater algae of China. Systematics, taxonomy and ecology. pp. [4 pls of 16 figs], [i-iv], i-xv, 1–1023. China: www.sciencep.com.
• McManus. Hilary A.. Lewis. Louise A.. Molecular phylogenetics, morphological variation and colony-form evolution in the family Hydrodictyaceae (Sphaeropleales, Chlorophyta). Phycologia. 44. 6. 2005. 582–595. 0031-8884. 10.2216/0031-8884(2005)44[582:MPMVAC]2.0.CO;2. free.
• Elgavish. A.. Halmann. M.. Berman. T.. A comparative study of phosphorus utilization and storage in batch cultures of Peridinium cinctum, Pediastrum duplex and Cosmarium sp., from Lake Kinneret (Israel). Phycologia. 21. 1. 2019. 47–54. 0031-8884. 10.2216/i0031-8884-21-1-47.1.
• Lehman. John T.. Photosynthetic capacity and luxury uptake of carbon during phosphate limitation in Pediastrum duplex (Chlorophyceae). Journal of Phycology. 12. 2. 1976. 190–193. 0022-3646. 10.1111/j.1529-8817.1976.tb00500.x. 86230705 .
• Sigee. D. C.. Dean. A.. Levado. E.. Tobin. M. J.. Fourier-transform infrared spectroscopy of Pediastrum duplex: characterization of a micro-population isolated from a eutrophic lake. European Journal of Phycology. 37. 1. 2002 . 19–26. 0967-0262. 10.1017/S0967026201003444. 86259018 . pdf
• Smoliner, C. (1983). Das zähe leben der grünalge Pediastrum duplex. Mikrokosmos 8: 241–245.

External links

• Images of various infraspecies

Notes and References

1. Web site: Pediastrum duplex Meyen . Algaebase . 2010-07-30.
2. Web site: Protist Images: Pediastrum duplex . Protist.i.hosei.ac.jp . 2010-07-30.
3. Book: 978-3-443-60035-8 . Review of the Green Algal Genus Pediastrum; Implication for Pollen-analytical Research . 2001 . 127 . Jirí . Komárek . Vlasta . Jankovská . Bibliotheca Phycologica . Schweizerbart Science Publishers .
4. 10.1111/j.1529-8817.1988.tb04227.x . Ultrastructure of the gamete of Pediastrum duplex (Chlorophyceae) . 1988 . Wilcox . Lee W. . Floyd . Gary L. . Journal of Phycology . 24 . 2 . 140–146 . 84122175 .
5. Web site: 2006 Annual Checklist : Pediastrum duplex Meyen . Catalogue of Life . 2010-07-30.
6. Web site: Pediastrum duplex - Nomen.at - animals and plants . Nomen.at . 2010-07-30.
7. 10.1111/j.1529-8817.2010.00941.x . Distinguishing multiple lineages of Pediastrum duplex with morphometrics and a proposal for Lacunastrum gen. nov. . 2011 . McManus . Hilary A. . Lewis . Louise A. . Schultz . Eric T. . Journal of Phycology . 47 . 123–130 . 43130148 .