Prasinophytae

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Prasinophytae
Pyramimonas sp.

Pyramimonas sp.

Systematics
Domain : Eukaryotes (eukaryota)
without rank: Diaphoreticks
without rank: Archaeplastida
without rank: Chloroplastida
without rank: Chlorophyta
without rank: Prasinophytae
Scientific name
Prasinophytae
T. Christensen ex Ø. Moestrup & J. Throndsen

The Prasinophytae are a group of green algae that is directly assigned to the Chloroplastida . Some species are responsible for algal blooms .

features

Most representatives are bean- to star-shaped flagellated unicellular organisms. There are also uncultivated (cocoidal) forms. They are among the smallest eukaryotic plankton species.

The cells have one, two, four or eight flagella that attach to a flagellum. The flagella strike like a breaststroke. The basal body roots have a structure of the X2X2 configuration. In the flagellum apparatus there are multilayered structures ("multilayered structures", MLS) that are considered to be originally for the green algae. There are organic scales on the cell surface. There are up to seven scale types per species. The outer cuticle forms a theka. The scales are formed in the Golgi apparatus . In mitosis , the metacentric spindle collapses in the telophase .

Some species form cysts up to 1 mm in size as persistence forms, so-called phycomata (singular phycoma). These include B. Halosphaera . Something similar is known of fossil algae from the Proterozoic and Paleozoic Era .

Nutrition occurs through autotrophy ( photosynthesis ) or osmotrophy . Also mixotrophy occurs.

Occurrence

The Prasinophytae are important representatives of the marine plankton. They can make up a substantial part of the plankton biomass. There are also representatives in brackish and fresh water.

Systematics

The size of the Prasinophytae is subject to strong changes, since the group should not be monophyletic. The following is the system according to Adl 2012:

The Chlorodendrales , in Lewis and McCourt still part of the Prasinophytae, are according to Adl et al. no longer classified here, but placed directly with the Chlorophyta, as well as Nephroselmis .

literature

  • Sina M. Adl, Alastair GB Simpson, Mark A. Farmer, Robert A. Andersen, O. Roger Anderson, John A. Barta, Samual S. Bowser, Guy Bragerolle, Robert A. Fensome, Suzanne Fredericq, Timothy Y. James, Sergei Karpov, Paul Kugrens, John Krug, Christopher E. Lane, Louise A. Lewis, Jean Lodge, Denis H. Lynn, David G. Mann, Richard M. McCourt, Leonel Mendoza, Øjvind Moestrup, Sharon E. Mozley-Standridge, Thomas A. Nerad, Carol A. Shearer, Alexey V. Smirnov, Frederick W. Spiegel, Max FJR Taylor: The New Higher Level Classification of Eukaryotes with Emphasis on the Taxonomy of Protists. In: The Journal of Eukaryotic Microbiology. 52 (5), 2005; Pages 399-451. doi : 10.1111 / j.1550-7408.2005.00053.x .
  • Louise A. Lewis, Richard M. McCourt: Green Algae and the Origin of Land Plants. In: American Journal of Botany. 91 (10), 2004, pp. 1535-1556. Abstract and full text

Individual evidence

  1. ^ Paul G. Falkowski and Andrew H. Knoll: Evolution of Primary Producers in the Sea . ISBN 978-0-12-370518-1 .
  2. ↑ ScienceDirect
  3. ^ Lewis, McCourt: Green Algae and the origin of land plants , 2004.
  4. ↑ Adl, SM, Simpson, AGB, Lane, CE, Lukeš, J., Bass, D., Bowser, SS, Brown, MW, Burki, F., Dunthorn, M., Hampl, V., Heiss, A. , Hoppenrath, M., Lara, E., le Gall, L., Lynn, DH, McManus, H., Mitchell, EAD, Mozley-Stanridge, SE, Parfrey, LW, Pawlowski, J., Rueckert, S., Shadwick, L., Schoch, CL, Smirnov, A. and Spiegel, FW: The Revised Classification of Eukaryotes. Journal of Eukaryotic Microbiology , 59: 429-514, 2012. doi : 10.1111 / j.1550-7408.2012.00644.x

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