Biology:Pleodorina
Pleodorina is a genus of colonial green algae in the family Volvocaceae.[1] It occurs in freshwater habitats and has a cosmopolitan distribution.[2]
Description
Pleodorina consists of motile colonies of 32 to 128 cells, which are arranged in the periphery of a gelatinous matrix, forming a hollow sphere. Cells are differentiated into those that are purely vegetative in character (somatic cells) and those capable of dividing to form daughter colonies (reproductive cells).[3] Somatic cells are smaller than reproductive cells and are located in the anterior part of the colony, while reproductive cells occupy the rest of the colony.[2] In one species Pleodorina sphaerica, somatic cells are also randomly distributed amongst reproductive cells.[4] In some species, individual cells are surrounded by a gelatinous sheath. All cells are biflagellate (with two equal flagella), and have a cup-shaped chloroplast, an stigma, many contractile vacuoles, and one to many pyrenoids.[3][2]
The young colonies of Pleodorina look very much like those of Eudorina.[3]
Asexual reproduction occurs by autocolony formation, in which the reproductive cells undergo successive cell divisions to become a curved plate or plakea, which inverts to form a daughter colony. Sexual reproduction is anisogamous, where reproductive cells either successively divide into sperm packets or female gametes without cell division.[5]
Taxonomy
Morphologically and reproductively, Pleodorina and Eudorina are similar to each other; in the past, some authors considered Pleodorina to be a synonym of the latter.[6] In addition, the boundary between the two genera are blurred by species such as Eudorina illinoisensis (once classified as Pleodorina sphaerica). E. illinoisensis has four anterior cells that are smaller than the rest of the cells, and are facultatively somatic.[2] Currently, Pleodorina is distinguished by having obligately somatic cells, while in Eudorina these obligately somatic cells are absent.[5]
Within Pleodorina, species are distinguished by morphological characters such as the number of cells,[7] position of the somatic cells, percentage of cells which are somatic, whether or not there is a gradual increase in cell size from anterior to posterior, and the presence or absence of gelatinous sheaths surrounding individual cells. The presence of gelatinous sheaths is generally only visible after staining with a dye such as methylene blue.[8]
Phylogeny
Molecular phylogenetic studies show that Pleodorina is polyphyletic and consist of three clades, nested within Eudorina:[4][9][10][11]
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
References
- ↑ See the NCBI webpage on Pleodorina. Data extracted from the "NCBI taxonomy resources". National Center for Biotechnology Information. https://ftp.ncbi.nih.gov/pub/taxonomy/.
- ↑ 2.0 2.1 2.2 2.3 Nakada, Takashi; Nozaki, Hisayoshi (2014). "Chapter 6. Flagellate Green Algae". Freshwater Algae of North America: Ecology and Classification (2 ed.). Elsevier Inc.. pp. 265–313. ISBN 978-0-12-385876-4.
- ↑ 3.0 3.1 3.2 Cite error: Invalid
<ref>tag; no text was provided for refs namedSmith - ↑ 4.0 4.1 Nozaki, Hisayoshi; Mahakham, Wuttipong; Athibai, Sujeephon; Yamamoto, Kayoko; Takusagawa, Mari; Misumi, Osami; Herron, Matthew D.; Rosenzweig, Frank et al. (2017). "Rediscovery of the "ancestral Volvox" species: Morphology and phylogenetic position of Pleodorina sphaerica (Volvocales, Chlorophyceae) from Thailand". Phycologia 56 (4): 469–475. doi:10.2216/17-3.1. PMID 29375162. Bibcode: 2017Phyco..56..469N.
- ↑ 5.0 5.1 Cite error: Invalid
<ref>tag; no text was provided for refs namedAlgaeBase - ↑ Goldstein, Melvin (1964). "Speciation and Mating Behavior in Eudorina". The Journal of Protozoology 11 (3): 317–344. doi:10.1111/j.1550-7408.1964.tb01762.x.
- ↑ Nozaki, Hisayoshi (2006). "Morphology, molecular phylogeny and taxonomy of two new species of Pleodorina (Volvocaceae, Chlorophyceae)". Journal of Phycology 42 (5): 1072–1080. doi:10.1111/j.1529-8817.2006.00255.x. Bibcode: 2006JPcgy..42.1072N. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1529-8817.2006.00255.x. Retrieved 3 June 2024.
- ↑ Nozaki, Hisayoshi; Kuroiwa, Haruko; Mita, Takashi; Kuroiwa, Tsuneyoshi (1989). "Pleodorina japonica sp. nov. (Volvocales, Chlorophyta) with bacteria-like endosymbionts". Phycologia 28 (2): 252–267. doi:10.2216/i0031-8884-28-2-252.1. Bibcode: 1989Phyco..28..252N.
- ↑ Lindsey, Charles Ross; Rosenzweig, Frank; Herron, Matthew D. (2021). "Phylotranscriptomics points to multiple independent origins of multicellularity and cellular differentiation in the volvocine algae". BMC Biology 19 (1): 182. doi:10.1186/s12915-021-01087-0. PMID 34465312. Bibcode: 2021BMCB...19..182L.
- ↑ Ma, Xiaoya; Shi, Xuan; Wang, Qiuping; Zhao, Mengru; Zhang, Zhenhua; Zhong, Bojian (2023). "A Reinvestigation of Multiple Independent Evolution and Triassic–Jurassic Origins of Multicellular Volvocine Algae". Genome Biology and Evolution 15 (8). doi:10.1093/gbe/evad142. PMID 37498572.
- ↑ Lindsey, Charles Ross; Knoll, Andrew H.; Herron, Matthew D.; Rosenzweig, Frank (2024-04-10). "Fossil-calibrated molecular clock data enable reconstruction of steps leading to differentiated multicellularity and anisogamy in the Volvocine algae". BMC Biology 22 (1): 79. doi:10.1186/s12915-024-01878-1. ISSN 1741-7007. PMID 38600528. Bibcode: 2024BMCB...22...79L.
- ↑ Nozaki, Hisayoshi; Matsuzaki, Ryo; Kashindye, Benedicto Boniphace; Ezekiel, Charles Nyarongo; Shaban, Sophia; Kawachi, Masanobu; Aibara, Mitsuto; Nikaido, Masato (2019). "Morphology, phylogeny, and taxonomy of two species of colonial volvocine green algae from Lake Victoria, Tanzania". PLOS ONE 14 (11). doi:10.1371/journal.pone.0224269. PMID 31710621. Bibcode: 2019PLoSO..1424269N.
External links
- Pleodorina - Description with pictures
Wikidata ☰ Q300542 entry
 |  |
