Эдеогониум: Жасыл балдырлар туысының сипаттамасы

Genus of algae

Oedogonium is a genus of filamentous, free living green algae. It was first discovered in the fresh waters of Poland in 1860 by W. Hilse, and later given its name by German scientist K. E. Hirn. The morphology of Oedogonium is unique, with an interior and exterior that function differently from one another and change throughout its life cycle. These algae reside in freshwater ecosystems in both hemispheres and are both benthic and planktonic in nature. They form algal patches on the water's surface and so interact closely with a multitude of other algae. These filamentous cells' life cycles include both sexual and asexual reproduction, depending on the life cycle stage. Although quite common, Oedogonium is difficult to identify since key definitive markers are only present during reproduction, which is an uncommon life stage among this genus. Oedogonium has been found to be important in the fixation of heavy metals in freshwater ecosystems.

First named Oedogoniaceen (in German), the name Oedogoniales is derived from the Latin oedos (meaning swelling or tumor) and gonos (meaning offspring or seed). This name describes the morphology that Hirn witnessed during Oedogonium sexual and asexual reproduction and later described in his publication, “Monographie und iconographie der Oedogoniaceen."

Oedogonium species were first reported in the late 19th century by Hilse (1860), Gołowin (1964), Kirchner (1878), Kozłowski (1895) and Gutwiński (1897). Mrozińska

In 1991, a paper by Mrozińska presented a new taxonomic classification of the genus Oedogonium, and a proposed division into two sections: I. Monospermatozoideae and II. Dispermatozoideae. These sections were based on the different number of spermatozoids the antheridial (male sex organ containing) cell expresses. The holdfast is also the only colourless cell of the filament. All other cells in the filament exist as green structures very similar in nature, with only some cells having caps. The number of caps per cell illustrates the number of times that cell has divided. Every cell of the filament has a cell wall consisting of three layers – the innermost is made of cellulose, the middle of pectose, and the outermost is made of chitin, all three of which provide rigidity and protection. Most cells are attached to the substrate by the holdfast and are vegetative cells, although some are free floating. Species of Oedogonium are divided into two major groups based on distribution of the sex organs: macrandous and nannandrous species. Oedogonium contain chloroplasts with a distinctive genome architecture. This genome is 196,547bp in length, and is the most compact among photosynthetic chlorophytes. It has a nonconforming quadripartite structure, with 17 group I and 4 group II introns – making it intron rich. It has four long open reading frames (ORFs), containing 99 different conserved genes. Two of these ORFs show high similarities to genes not usually found in cpDNA (chloroplast DNAs). These molecular signatures are evidence for the theory that Oedogonium is the earliest diverging lineage of the OCC clade. When blooms are in effect, removing these cells has a positive effect on their ecosystem and may be dried and used to effectively absorb harmful heavy metals from other freshwater systems such as industrial wastes. Oedogonium can also significantly clog irrigation canals when their growth on concrete surfaces becomes excessive due to high levels of benthic filaments.

Oedogonium yunnanense C. C. Jao, 1979