Charales
Encyclopedia
Charales is an order of pondweeds, freshwater algae
in the division Charophyta
. They are green plants believed to be the closest relatives of the green land plants. Linnaeus established the genus Chara in 1753.
to photosynthesize. They grow in fresh water
. They may be called stoneworts, because the plants can become encrusted in lime (calcium carbonate
) after some time. The "stem" is actually a central stalk consisting of giant, multinucleated cells
. They are unique in having a whorl of small branchlets at each node in the stipe
, this gives them a superficial resemblance to the genus Equisetum. In these whorls it is possible to see the phenomenon of cytoplasmic streaming
. In fact the streaming in Chara is the fastest recorded of any cell. Cytoplasmic streaming is caused by the microfilaments found inside the cell, as proven by the use of cytochalasin B to stop streaming.
There are about 400 species
worldwide, with 33 in Britain
and Ireland
according to Groves and Bullock-Webster), however Stewart and Church (1992) reduce this to 21.
Characeae are the principal plant life of some of the volcanic crater lakes of Nicaragua, and can be found in excess of 20 meters depth in some circumstances. Introduced tilapia (Oreochromis niloticus) consumed all the Characeae in Lake Apoyo.
.
when mature; the oogonium is oblong in shape and consists of a single egg, while the spherical antheridium is packed with threadlike cells that produce spermatia. As a result, the Charales have the most complex structure of all green algae, if indeed they should be so labelled.
The possible ancestors of the land plants are also known as brittleworts or skunkweed. These curious labels arise from the fragility of their lime-encrusted stems, and from the foul odor these produce when stepped on.
Many botanists
propose that the stoneworts and their relatives be placed in a phylum
, division, sub-kingdom, or even kingdom by themselves, often named Charophyta
. Their classification
by taxonomists
is currently undergoing much cladistic
scrutiny. Further DNA
and RNA
analysis may prove the charophytes to be a crucial evolutionary link
in the phylogenetic tree
of life, the critical developmental step from the algae
toward the non-vascular
and then vascular
land plants.
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
in the division Charophyta
Charophyta
The Charophyta are a division of green algae, including the closest relatives of the embryophyte plants. In some groups, such as conjugating green algae, flagellate cells do not occur. The latter group does engage in sexual reproduction, and motility does not involve flagella, since they are...
. They are green plants believed to be the closest relatives of the green land plants. Linnaeus established the genus Chara in 1753.
Description
The Charales have large, macroscopic thalli growing up to 120 cm long, they are branched, multicellular, and use chlorophyllChlorophyll
Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
to photosynthesize. They grow in fresh water
Fresh Water
Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...
. They may be called stoneworts, because the plants can become encrusted in lime (calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
) after some time. The "stem" is actually a central stalk consisting of giant, multinucleated cells
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
. They are unique in having a whorl of small branchlets at each node in the stipe
Stipe (botany)
In botany, a stipe is a stalk that supports some other structure. The precise meaning is different depending on which taxonomic group is being described....
, this gives them a superficial resemblance to the genus Equisetum. In these whorls it is possible to see the phenomenon of cytoplasmic streaming
Cytoplasmic streaming
Cytoplasmic streaming is the directed flow of cytosol and organelles around large fungal and plant cells. This movement aids in the delivery of nutrients, metabolites, genetic information, and other materials to all parts of the cell...
. In fact the streaming in Chara is the fastest recorded of any cell. Cytoplasmic streaming is caused by the microfilaments found inside the cell, as proven by the use of cytochalasin B to stop streaming.
There are about 400 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
worldwide, with 33 in Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
and Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
according to Groves and Bullock-Webster), however Stewart and Church (1992) reduce this to 21.
Characeae are the principal plant life of some of the volcanic crater lakes of Nicaragua, and can be found in excess of 20 meters depth in some circumstances. Introduced tilapia (Oreochromis niloticus) consumed all the Characeae in Lake Apoyo.
Species
British Isles
Ref: Stewart & Church (1992).- Chara baltica Bruz.
- Chara canescens Desv. & Lois.
- Chara connivens Salzm. ex A.Braun
- Chara curta Nolta wx Kütz. (=C.aspera var. curta)
- Chara denudata (A.Braun) R.D.Wood
- Chara fragifera Durieu
- Chara intermedia Braun (=C. papillosa Kütz. and C. contraria x hispida)
- Chara mucosa J.Groves & Bullock-Webster
- Chara rudis (A.Braun) Leonh.
- Chara tomentosa L.
- Lamprothamnium papulosum (Wallr.) J.Groves
- Nitella capillaris (Krocker) J.Groves & Bullock-Webster
- Nitella gracilis (Smith) Agardh
- Nitella hyalina (DC.)Agardh
- Nitella mucronata (A.Braun)Miquel
- Nitella spanioclema J.Groves & Bullock-Webster (Nitella flexilis var. spanioclema (J.Groves & Bullock-Webster)
- Nitella tenuissima (Desv.) Kütz.
- Nitellopsis obtusa (Desv.) J.Groves
- Tolypella intricata (Trent. ex Roth) Leonh.
- Tolypella nidifica (O.F.Müll.) Leonh. (= Tolypella nidifica var. nidifica)
- Tolypella prolifera (Ziz. ex A.Braun) Leonh.
Other regions
- Family Chaetosphaeridiaceae
- Chaetosphaeridium globosumChaetosphaeridium globosumChaetosphaeridium globosum is a one-celled algae which is thought to represent an ancient lineage of the green plants. This organism exists in a filamentous form with one flagella per cell. It is a freshwater species. The flagellum is covered in scales in a 3-prong irregular shape called ‘maple...
(Nordst.) Klebahn, 1893 - Chaetosphaeridium ovalis G. M. Smith, 1916
- Chaetosphaeridium pringsheimii Klebahn, 1892
- Conochaete comosa Klebahn, 1893
- Diplochaete solitaria Collins, 1901
- Chaetosphaeridium globosum
Ireland
- Co. Antrim
- C.aspera Deth. ex Willd. var. aspera
- C. globularis Thuill. var. globularis
- C. vulgaris var. papillata Wallr. ex A. Braun
- C. globularis var. virgata (Kützing) R.D.Wood
- C. vulgaris L. var. vulgaris
- C. vulgaris L. var. contraria (A.Braun ex Kützing) J.A. Moore
- C. vulgaris var. longibracteata (Kützing) J. Groves & Bullock-Webster
- C. vulgaris var. papillata Wallr. ex A. Braun
- Nitella flexilis (L.) var. flexilis
- Nitella translucens (Pers.) C.A. Ag.
- Tolypella nidifica (O. Mill.) Leonh. var. glomerata (Desv.) R.D.Wood
- Co. Down
- C. aspera Deth. ex Willd. var. aspera
- C. aspera var. curta (Nolte ex Kützing) Braun ex Leonh.
- C. globularis Thuill. var. globularis
- C. vulgaris var. papillata Wallr. ex A. Braun
- C. globularis var. virgata (Kützing) R.D.Wood
- C. globularis var. annulata (Lilleblad) J.A.Moore
- C. hispida L.
- C. hispida var. hispida
- C. hispida var. major (Hartm.) R.D. Wood
- C. hispida var. rudis A. Braun
- C. pedunculata Kützing
- C. vulgaris L. var. vulgaris
- C. vulgaris L. var. contraria (A.Braun ex Kützing) J.A. Moore
- C. vulgaris var. longibracteata (Kützing) J. Groves & Bullock-Webster
- C. vulgaris var. papillata Wallr. ex A. Braun
- Nitella flexilis (L.) var. flexilis
- Nitella translucens (Pers) C.A. Ag.
- Tolypella nidifica (O. Mill.) Leonh. var. glomerata (Desv.) R.D.Wood
- Co. Londonderry
- C.aspera Deth. ex Willd. var. aspera
- C. vulgaris var. papillata Wallr. ex A. Braun
- C. globularis Thuill. var. globularis
- C. globularis var. virgata (Kützing) R.D.Wood
- C. hispida L.
- C. hispida var. hispida
- C. vulgaris L. var. vulgaris
- C. vulgaris L. var. contraria (A.Braun ex Kützing) J.A. Moore
- C. vulgaris var. papillata Wallr. ex A. Braun
- Nitella flexilis (L.) var. flexilis
- Nitella translucens (Pers) C.A. Ag.
- Tolypella nidifica (O. Mill.) Leonh. var. glomerata (Desv.) R.D.Wood
- Co. Mayo.Recent records have been published from Clare Island.
- C. virgata Kützing
- N. flexilis (Linnaeus) C.Agardh
- N. translucens (Persoon) C.Agardh
Ecology
The Characeae are aquatic though some can survive in brackish or maritime habitats. They are to be found usually in still, clear, non-flowing, water attached by rhizoids. They can be pioneer colonizers or ephemerals. They are usually found in low to medium nutrient-rich water and tend to disappear due to eutrophicationEutrophication
Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...
.
Life history
The antheridia and oogonia are protected by a layer of sterile cellsCell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
when mature; the oogonium is oblong in shape and consists of a single egg, while the spherical antheridium is packed with threadlike cells that produce spermatia. As a result, the Charales have the most complex structure of all green algae, if indeed they should be so labelled.
The possible ancestors of the land plants are also known as brittleworts or skunkweed. These curious labels arise from the fragility of their lime-encrusted stems, and from the foul odor these produce when stepped on.
Many botanists
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
propose that the stoneworts and their relatives be placed in a phylum
Phylum
In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division....
, division, sub-kingdom, or even kingdom by themselves, often named Charophyta
Charophyta
The Charophyta are a division of green algae, including the closest relatives of the embryophyte plants. In some groups, such as conjugating green algae, flagellate cells do not occur. The latter group does engage in sexual reproduction, and motility does not involve flagella, since they are...
. Their classification
Biological classification
Biological classification, or scientific classification in biology, is a method to group and categorize organisms by biological type, such as genus or species. Biological classification is part of scientific taxonomy....
by taxonomists
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
is currently undergoing much cladistic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
scrutiny. Further DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
and RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
analysis may prove the charophytes to be a crucial evolutionary link
Missing Link
Missing link is a nonscientific term for any transitional fossil, especially one connected with human evolution; see Transitional fossil - Missing links and List of transitonal fossils - Human evolution.Missing Link may refer to:...
in the phylogenetic tree
Phylogenetic tree
A phylogenetic tree or evolutionary tree is a branching diagram or "tree" showing the inferred evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical and/or genetic characteristics...
of life, the critical developmental step from the algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
toward the non-vascular
Bryophyte
Bryophyte is a traditional name used to refer to all embryophytes that do not have true vascular tissue and are therefore called 'non-vascular plants'. Some bryophytes do have specialized tissues for the transport of water; however since these do not contain lignin, they are not considered to be...
and then vascular
Vascular plant
Vascular plants are those plants that have lignified tissues for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the clubmosses, Equisetum, ferns, gymnosperms and angiosperms...
land plants.
Further reading
- Bryant, J. The stoneworts (Chlorophyta, Charales). In Guiry, M.D., John, D.M., Rindi, F. and McCarthy, T.K. 2007. New Survey of Clare Island. Royal Irish Academy. ISBN 978-904890-31-7.
- Lloyd, James. 2007. "Cytoskeletal Structures Responsible for Cytoplasmic Streaming in Chara." St. Vincent-St. Mary High School in Accordance with Dr. Donald Ott of The University of Akron. (Science Inquiry)
- Schaible, R. and Schubert, H. 2008. The ccurrence of sexual Chara canesces populations (Charophyceae) is not related to ecophysiological potentials with respect to salinity and irradiance. Eur. J. Phycol. 43: 309 - 316.
- Desai, Udaysingh and Karande C.T. 2008. "Biodiversity of Charophytes from Kolhapur District, Maharashtra". Shivaji University, Kolhapur.