Frog spawn algae

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Frog spawn algae
Batrachospermum gelatinosum

Batrachospermum gelatinosum

Systematics
Department : Red algae (Rhodophyta)
Subdivision : Rhodophytina
Class : Florideophyceae
Order : Batrachospermales
Family : Batrachospermaceae
Genre : Frog spawn algae
Scientific name
Batrachospermum
Roth (1797)

The frog spawn algae ( Batrachospermum ) are a genus of red algae . It is freshwater algae that occur worldwide in slow-flowing, oxygen-rich waters. In Central Europe the genus is represented by the frog spawn alga B. gelatinosum . The term “frog spawn” is also used for other species of the genus, especially since these are difficult to distinguish from one another. With around 100 species, the genus comprises 2/3 of the red algae living in freshwater. The frog spawn algae were from the section Phykologie the German Botanical Society for the algae of the year chosen of 2010.

Description and reproduction

Like most red algae, the frog spawn algae go through a tripartite generation change in which a haploid gametophyte and two different diploid sporophytes follow one another. The name comes from a gelatinous slime made of oligosaccharides that surrounds the alga. Macroscopically striking is the gametophyte, which can be up to 40 cm long. It consists of a central thread of elongated cells strung together, on which whorl-like tufts of branched side threads sit at regular intervals. The sexual organs are formed at the ends of side threads: female carpogonia, which have an elongated, sometimes stalked process, the trichogyne, and contain a cell nucleus at the base, and male antheridia . The latter release the male gametes (spermatia), which are spherical in shape and 4–8 μm in size and, as with all red algae, do not have flagella but are moved passively by the water current. When a sperm meets a trichogyne, fertilization can occur, from which the diploid zygote emerges.

The zygote remains on the mother plant and forms the tiny, few- cell first generation of sporophytes, the carposporophytes or gonimoblasts. This also produces diploid carpos spores, which germinate into threadlike prothalli after their release. The prothallus planted one hand asexually by forming spores Mono from which further Prothalli emerge. In addition, meiosis takes place in terminal cells of short, upright growing threads , from which, in addition to two polar bodies, a cell emerges which - remaining on the prothallus - grows into the haploid gametophyte. This then also forms rhizoid- like threads that grow downwards and serve as anchoring.

Systematics

The genus Batrachospermum was established in 1797 by Albrecht Wilhelm Roth in comments on the study of the cryptogamic aquatic plants . At that time, the only known species was the frog spawn alga Batrachospermum gelatinosum , which is the type of Batrachospermum . Since then, numerous other species have been discovered. Molecular genetic studies led to the fact that in 2014 several species in the genus Sheathia were separated. In 2018 the species of Batrachospermum section Virescentia were moved to a separate genus Virescentia . In September 2018, according to AlgaeBase , Batrachospermum includes the following species:

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Individual evidence

  1. ↑ Albrecht Wilhelm Roth: Comments on the study of the cryptogamic aquatic plants . 109 p. Hanover, Gebr. Hahn. 1797. P. 36: First description of Batrachospermum
  2. ↑ Eric D. Salomaki, Janina Kwandrans, Pertti Eloranta, Morgan L. Vis: Molecular and morphological evidence for Sheathia gen. Nov. (Batrachospermales, Rhodophyta) and three new species. Journal of phycology 50 (3): pp. 526-542. 2014. doi : 10.1111 / jpy.12179 PDF .
  3. ↑ Orlando Necchi, Douglas de Castro Agostinho, Morgan L. Vis: Revision of Batrachospermum section Virescentia (Batrachospermales, Rhodophyta) with the establishment of the new genus, Virescentia stat. nov. Cryptogamie Algologie 39 (3): pp. 313-338. 2018. doi : 10.7872 / crya / v39.iss3.2018.313

Web links

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