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Chara (alga)

February 15, 2024

Chara is a genus of charophyte green algae in the family Characeae. They are multicellular and superficially resemble land plants because of stem-like and leaf-like structures. They are found in freshwater, particularly in limestone areas throughout the northern temperate zone, where they grow submerged, attached to the muddy bottom. They prefer less oxygenated and hard water and are not found in waters where mosquito larvae are present.[2] They are covered with calcium carbonate (CaCO3) deposits and are commonly known as stoneworts. Cyanobacteria have been found growing as epiphytes on the surfaces of Chara, where they may be involved in fixing nitrogen, which is important to plant nutrition.[3]

Chara
Temporal range: Silurian–Recent[1]
Chara globularis
Scientific classification
(unranked): Viridiplantae
(unranked): Charophyta
Class: Charophyceae
Order: Charales
Family: Characeae
Genus: Chara
L., 1753
Species

See text.

Light micrograph of unidentified cyanobacteria and other biofilm organisms growing as epiphytes on the surface of Chara species in a rice paddy in Louisiana, US

Structure edit

The branching system of Chara species is complex with branches derived from apical cells which cut off segments at the base to form nodal and internodal cells alternately.[4] The main axes bear whorls of branches in a superficial resemblance to Equisetum (a vascular plant).[5] They are typically anchored to the littoral substrate by means of branching underground rhizoids. Chara plants are rough to the touch because of deposited calcium salts on the cell wall. The metabolic processes associated with this deposition often give Chara plants a distinctive and unpleasant smell of hydrogen sulfide.[4]

Morphology edit

The plant body is a gametophyte. It consists of the main axis (differentiated into nodes and internodes), dimorphic branches (long branch of unlimited growth and short branches of limited growth), rhizoids (multicellular with oblique septa) and stipulodes (needle-shaped structures at the base of secondary laterals).[citation needed]

Reproduction edit

 
Light micrograph of a whole-mount slide of an oogonium (or nucule) and antheridium (or globule) of Chara (conjoined monoicy)

Chara reproduces vegetatively and sexually. Vegetative reproduction takes place by tubers, amylum stars and secondary protonemata. The sex organs are a multicellular and jacketed globule or antheridium (male) and nucule or archegonium (female). The antheridia and archegonia may occur on separate plants (dioicy), together on the same plant (conjoined monoicy) or separately on the same plant (sejoined monoicy).[6]

The reproductive organs of the Charales show a high degree of specialization. The female organ, called an oogonium is a large oval structure with an envelope of spirally arranged, bright green filaments of cells. The male organ or is also large, bright yellow or red in colour, spherical in shape, and is usually termed an antheridium, though some workers regard it as a multiple structure rather than a single organ. The sex organs are developed in pairs from the adaxial nodal cell at the upper nodes of the primary lateral branches, the oogonium being formed above the antheridium. They are sufficiently large to be easily seen with the naked eye, especially the bright orange or red antheridium. Many species are dioecious. In others the monoecious condition is complicated by the development of the antheridium before the formation of the oogonium, thus preventing fertilization by antherozoids of the same alga. In this case the two types of sex organs usually arise from different points on the lateral branches.

All cells of the Charales are haploid except for the fertilized zygote, the large single cell in the interior of the oogonium, which becomes enclosed in a thickened hard wall to form an oospore that awaits favorable conditions for germination. Upon germination the diploid oospore undergoes meiosis, producing four haploid nuclei. A septum divides a small apical cell with one haploid nucleus from a large basal cell containing the other three nuclei, which will slowly degenerate. The oospore apical cell divides to produce the protonemal initial, from which the primary protonema arises, and the rhizoidal initial, from which the primary rhizoid descends. From these the alga continues its development.[7]

Species edit

Distribution edit

Chara has a cosmopolitan distribution, from 69 degrees north in northern Norway to about 49 degrees south in Kerguelen Islands (Pal et al., 1962). About 27 species are found in India.[8] There are about 40 species of Chara in Europe, where they are commonly found in the specific habitat-type designated as H3140 (hard oligo-mesotrophic waters with benthic vegetation of Chara spp h1) in the Natura 2000 plans of the European Union. Although this habitat is found all across Europe, it is threatened and to be protected and preserved.

The Netherlands are home to 20 species of Chara, growing in lakes and ponds of the habitat-type H3140. The H3140 habitats in the Netherlands, are considered important in the overall preservation efforts and therefore also for the Chara species in general.[9]

Denmark. Here, many former Chara habitats (H3140) have been polluted by either toxins or excessive amounts of nutrients (in particular phosphates and nitrogen), but a few large lakes and ponds remain. Chara is found growing in the very clean hard water lakes of Thy National Park like Nors Sø for example. Tissø lake (fourth-largest lake in Denmark) is also a H3140 habitat and contains Chara species.[10][11]

Ireland:- Co. Galway. Eglinton Canal Chara virgata Kütz., Chara rudis (A.Braun) Leonhardii and Nitella flexilis (L.) C.Agardh.[12]

References edit

  1. ^ Palmer, Douglas; et al. (2009), Prehistoric Life: The Definitive Visual History of Life on Earth (first American ed.), Dorling Kindersley, p. 419, ISBN 978-0-7566-5573-0
  2. ^ Barber, M. A. (1924). "The Effect of Chara Robbinsii on Mosquito Larvæ". Public Health Reports. 39 (13): 611–615. doi:10.2307/4577099. ISSN 0094-6214. JSTOR 4577099.
  3. ^ Sims, G. K.; Dunigan, E. P. (1984). "Diurnal and seasonal variations in nitrogenase activity (C2H2 reduction) of rice roots". Soil Biology and Biochemistry. 16: 15–18. doi:10.1016/0038-0717(84)90118-4.
  4. ^ a b Round, F.E. 1965.The Biology of the algae. Ernest Arnold.
  5. ^ Bryant, J. 2007. The Stoneworts (Chlorophyta. Charales) in Guiry, M.D., John, D.M., Rindi, F. and McCarthy, T.K. 2007. New Survey of Clare Island. Volume 6: The Freshwater and Terrestrial Algae. Royal Irish Academy
  6. ^ McCracken, M.D.; Vernon, W.P.; Arland, T.H. (1966). "Attempted Hybridization between Monoecious and Dioecious Clones of Chara". American Journal of Botany. 53 (9): 937–940. doi:10.2307/2439818. JSTOR 2439818.
  7. ^ Dinesh Sharma (2016-02-04). "Chara: Occurrence, Structure and Reproduction".
  8. ^ Soni, N.K. Fundamentals of Botany Vol. 1, Tata McGraw-Hill Education, p72, ISBN 9780070681767
  9. ^ H3140 – Hard oligo-mesotrophic waters with benthic vegetation of Chara spp h1. December 27, 2013, at the Wayback Machine
  10. ^ 3140 Hard oligo-mesotrophic waters with benthic vegetation of Chara spp h1. December 27, 2013, at the Wayback Machine Danish Nature agency (in Danish)
  11. ^ Natura 2000 basic analysis 2015–2021 for Hanstholm Reservatet, Hanstholm Knuden, Nors Sø and Vandet Sø December 27, 2013, at the Wayback Machine Danish Nature Agency 2013 (in Danish) ISBN 978-87-7091-034-7
  12. ^ Pybus, C. and O'Halloran, P. 2009. Distribution of some submerged aquatic macrophytes in Eglinton Canal, Galway. Ir. Nat. J. 30: 51 – 53

February 15, 2024
chara, alga, chara, genus, charophyte, green, algae, family, characeae, they, multicellular, superficially, resemble, land, plants, because, stem, like, leaf, like, structures, they, found, freshwater, particularly, limestone, areas, throughout, northern, temp. Chara is a genus of charophyte green algae in the family Characeae They are multicellular and superficially resemble land plants because of stem like and leaf like structures They are found in freshwater particularly in limestone areas throughout the northern temperate zone where they grow submerged attached to the muddy bottom They prefer less oxygenated and hard water and are not found in waters where mosquito larvae are present 2 They are covered with calcium carbonate CaCO3 deposits and are commonly known as stoneworts Cyanobacteria have been found growing as epiphytes on the surfaces of Chara where they may be involved in fixing nitrogen which is important to plant nutrition 3 CharaTemporal range Silurian Recent 1 PreꞒ Ꞓ O S D C P T J K Pg NChara globularisScientific classification unranked Viridiplantae unranked CharophytaClass CharophyceaeOrder CharalesFamily CharaceaeGenus CharaL 1753SpeciesSee text Light micrograph of unidentified cyanobacteria and other biofilm organisms growing as epiphytes on the surface of Chara species in a rice paddy in Louisiana USContents 1 Structure 2 Morphology 3 Reproduction 4 Species 5 Distribution 6 ReferencesStructure editThe branching system of Chara species is complex with branches derived from apical cells which cut off segments at the base to form nodal and internodal cells alternately 4 The main axes bear whorls of branches in a superficial resemblance to Equisetum a vascular plant 5 They are typically anchored to the littoral substrate by means of branching underground rhizoids Chara plants are rough to the touch because of deposited calcium salts on the cell wall The metabolic processes associated with this deposition often give Charaplants a distinctive and unpleasant smell of hydrogen sulfide 4 Morphology editThe plant body is a gametophyte It consists of the main axis differentiated into nodes and internodes dimorphic branches long branch of unlimited growth and short branches of limited growth rhizoids multicellular with oblique septa and stipulodes needle shaped structures at the base of secondary laterals citation needed Reproduction edit nbsp Light micrograph of a whole mount slide of an oogonium or nucule and antheridium or globule of Chara conjoined monoicy Chara reproduces vegetatively and sexually Vegetative reproduction takes place by tubers amylum stars and secondary protonemata The sex organs are a multicellular and jacketed globule or antheridium male and nucule or archegonium female The antheridia and archegonia may occur on separate plants dioicy together on the same plant conjoined monoicy or separately on the same plant sejoined monoicy 6 The reproductive organs of the Charales show a high degree of specialization The female organ called an oogonium is a large oval structure with an envelope of spirally arranged bright green filaments of cells The male organ or is also large bright yellow or red in colour spherical in shape and is usually termed an antheridium though some workers regard it as a multiple structure rather than a single organ The sex organs are developed in pairs from the adaxial nodal cell at the upper nodes of the primary lateral branches the oogonium being formed above the antheridium They are sufficiently large to be easily seen with the naked eye especially the bright orange or red antheridium Many species are dioecious In others the monoecious condition is complicated by the development of the antheridium before the formation of the oogonium thus preventing fertilization by antherozoids of the same alga In this case the two types of sex organs usually arise from different points on the lateral branches All cells of the Charales are haploid except for the fertilized zygote the large single cell in the interior of the oogonium which becomes enclosed in a thickened hard wall to form an oospore that awaits favorable conditions for germination Upon germination the diploid oospore undergoes meiosis producing four haploid nuclei A septum divides a small apical cell with one haploid nucleus from a large basal cell containing the other three nuclei which will slowly degenerate The oospore apical cell divides to produce the protonemal initial from which the primary protonema arises and the rhizoidal initial from which the primary rhizoid descends From these the alga continues its development 7 Species editChara braunii Report Integrated Taxonomic Information System Chara canescens Report Integrated Taxonomic Information System Chara contraria Report Integrated Taxonomic Information System opposite stonewort Chara corallina Report Integrated Taxonomic Information System Chara elegans Report Integrated Taxonomic Information System Chara excelsa Report Integrated Taxonomic Information System Chara fibrosa Report Integrated Taxonomic Information System Chara formosa Report Integrated Taxonomic Information System Chara fragilis Report Integrated Taxonomic Information System Chara globularis Report Integrated Taxonomic Information System Chara hispida Report Integrated Taxonomic Information System Chara hornemannii Report Integrated Taxonomic Information System Chara intermedia Report Integrated Taxonomic Information System Chara nataklys Chara sejuncta Report Integrated Taxonomic Information System Chara virgata Report Integrated Taxonomic Information System Chara vulgaris Report Integrated Taxonomic Information System Chara zeylanica Report Integrated Taxonomic Information System Chara connivens convergent stonewort Chara wallichiiDistribution editThis section needs expansion You can help by adding to it December 2012 Chara has a cosmopolitan distribution from 69 degrees north in northern Norway to about 49 degrees south in Kerguelen Islands Pal et al 1962 About 27 species are found in India 8 There are about 40 species of Chara in Europe where they are commonly found in the specific habitat type designated as H3140 hard oligo mesotrophic waters with benthic vegetation of Chara spp h1 in the Natura 2000 plans of the European Union Although this habitat is found all across Europe it is threatened and to be protected and preserved The Netherlands are home to 20 species of Chara growing in lakes and ponds of the habitat type H3140 The H3140 habitats in the Netherlands are considered important in the overall preservation efforts and therefore also for the Chara species in general 9 Denmark Here many former Chara habitats H3140 have been polluted by either toxins or excessive amounts of nutrients in particular phosphates and nitrogen but a few large lakes and ponds remain Chara is found growing in the very clean hard water lakes of Thy National Park like Nors So for example Tisso lake fourth largest lake in Denmark is also a H3140 habitat and contains Chara species 10 11 Ireland Co Galway Eglinton Canal Chara virgata Kutz Chara rudis A Braun Leonhardii and Nitella flexilis L C Agardh 12 References edit Palmer Douglas et al 2009 Prehistoric Life The Definitive Visual History of Life on Earth first American ed Dorling Kindersley p 419 ISBN 978 0 7566 5573 0 Barber M A 1924 The Effect of Chara Robbinsii on Mosquito Larvae Public Health Reports 39 13 611 615 doi 10 2307 4577099 ISSN 0094 6214 JSTOR 4577099 Sims G K Dunigan E P 1984 Diurnal and seasonal variations in nitrogenase activity C2H2 reduction of rice roots Soil Biology and Biochemistry 16 15 18 doi 10 1016 0038 0717 84 90118 4 a b Round F E 1965 The Biology of the algae Ernest Arnold Bryant J 2007 The Stoneworts Chlorophyta Charales in Guiry M D John D M Rindi F and McCarthy T K 2007 New Survey of Clare Island Volume 6 The Freshwater and Terrestrial Algae Royal Irish Academy McCracken M D Vernon W P Arland T H 1966 Attempted Hybridization between Monoecious and Dioecious Clones of Chara American Journal of Botany 53 9 937 940 doi 10 2307 2439818 JSTOR 2439818 Dinesh Sharma 2016 02 04 Chara Occurrence Structure and Reproduction Soni N K Fundamentals of Botany Vol 1 Tata McGraw Hill Education p72 ISBN 9780070681767 H3140 Hard oligo mesotrophic waters with benthic vegetation of Chara spp h1 Archived December 27 2013 at the Wayback Machine 3140 Hard oligo mesotrophic waters with benthic vegetation of Chara spp h1 Archived December 27 2013 at the Wayback Machine Danish Nature agency in Danish Natura 2000 basic analysis 2015 2021 for Hanstholm Reservatet Hanstholm Knuden Nors So and Vandet So Archived December 27 2013 at the Wayback Machine Danish Nature Agency 2013 in Danish ISBN 978 87 7091 034 7 Pybus C and O Halloran P 2009 Distribution of some submerged aquatic macrophytes in Eglinton Canal Galway Ir Nat J 30 51 53 Retrieved from https en wikipedia org w index php title Chara alga amp oldid 1184783196, wikipedia, wiki, book, books, library,

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