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Myrothamnanae
The Gunnerales are an order of flowering plants. In the APG III system (2009) and APG IV system (2016) it contains two genera: ''Gunnera'' (in family Gunneraceae) and ''Myrothamnus'' (in family Myrothamnaceae). In the Cronquist system (1981), the Gunneraceae were in the Haloragales and Myrothamnaceae in the Hamamelidales. DNA analysis was definitive, but the grouping of the two families was a surprise, given their very dissimilar morphologies. In Cronquist's old system (1981, 1988), and Takhtajan's (1997), the Gunneraceae were in the Rosidae, and the Myrothamnaceae were in the Hamamelids. In modern classification systems such as APG III and APG IV this order was the first to derive from the core eudicots. Description Both families contain ellagic acid. Phloem cells contain a large number of plastids and the leaves have dented borders. The plants are dioecious, have small flowers without perianth, and the stigma is at least weakly secretory. Gunnerales characters shared with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gunnera
''Gunnera'' is the sole genus of herbaceous flowering plants in the family Gunneraceae, which contains 63 species. Some species in this genus, namely those in the subgenus ''Panke'', have extremely large leaves. Species in the genus are variously native to Latin America, Australia, New Zealand, Papuasia, Hawaii, insular Southeast Asia, Africa, and Madagascar. The stalks of many species are edible. Taxonomy ''Gunnera'' is the only genus in the family Gunneraceae. The APG II system, of 2003, also recognizes this family and assigns it to the order Gunnerales in the clade core eudicots. The family then consisted of one or two genera, ''Gunnera'' and, optionally, '' Myrothamnus'', the latter optionally segregated as a separate family, Myrothamnaceae. This represents a change from the APG system, of 1998, which firmly recognized two separate families, unplaced as to order. The APG III system and APG IV system recognizes the family Gunneraceae and places ''Myrothamnus'' in Myroth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Botanical Journal Of The Linnean Society
The ''Botanical Journal of the Linnean Society'' is a scientific journal publishing original papers relating to the taxonomy of all plant groups and fungi, including anatomy, biosystematics, cytology, ecology, ethnobotany, electron microscopy, morphogenesis, palaeobotany, palynology and phytochemistry.Botanical Journal of the Linnean Society The journal is published by the Linnean Society of London and is available in both print and searchable online formats. Like the '' Biological Journal of the Linnean Society'' (publ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gunnerales
The Gunnerales are an order of flowering plants. In the APG III system (2009) and APG IV system (2016) it contains two genera: ''Gunnera'' (in family Gunneraceae) and ''Myrothamnus'' (in family Myrothamnaceae). In the Cronquist system (1981), the Gunneraceae were in the Haloragales and Myrothamnaceae in the Hamamelidales. DNA analysis was definitive, but the grouping of the two families was a surprise, given their very dissimilar morphologies. In Cronquist's old system (1981, 1988), and Takhtajan's (1997), the Gunneraceae were in the Rosidae, and the Myrothamnaceae were in the Hamamelids. In modern classification systems such as APG III and APG IV this order was the first to derive from the core eudicots. Description Both families contain ellagic acid. Phloem cells contain a large number of plastids and the leaves have dented borders. The plants are dioecious, have small flowers without perianth, and the stigma is at least weakly secretory. Gunnerales characters shared with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondria
A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'' was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase coined by Philip Siekevitz in a 1957 article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). A large number of unicellular organisms, such as microsporidia, parabasalids and diplomonads, have reduced or transformed their mitochondria into other structures. One eukaryote, '' Monocercomonoides'', is known to have completely lost its mitochondria, and one multicellular orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzylisoquinoline
Substitution of the heterocycle isoquinoline at the C1 position by a benzyl group provides 1‑benzylisoquinoline, the most widely examined of the numerous benzylisoquinoline structural isomers. The 1-benzylisoquinoline moiety can be identified within numerous compounds of pharmaceutical interest, such as moxaverine; but most notably it is found within the structures of a wide variety of plant natural products, collectively referred to as benzylisoquinoline alkaloids. This class is exemplified in part by the following compounds: papaverine, noscapine, codeine, morphine, apomorphine, berberine, tubocurarine. Biosynthesis (''S'')- Norcoclaurine ( higenamine) has been identified as the central 1-benzyl-tetrahydro-isoquinoline precursor from which numerous complex biosynthetic pathways eventually emerge. These pathways collectively lead to the structurally disparate compounds comprising the broad classification of plant natural products referred to as benzylisoquinoline alkaloids (BI ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenylalanine
Phenylalanine (symbol Phe or F) is an essential α-amino acid with the formula . It can be viewed as a benzyl group substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of alanine. This essential amino acid is classified as neutral, and nonpolar because of the inert and hydrophobic nature of the benzyl side chain. The L-isomer is used to biochemically form proteins coded for by DNA. Phenylalanine is a precursor for tyrosine, the monoamine neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), and the skin pigment melanin. It is encoded by the codons UUU and UUC. Phenylalanine is found naturally in the milk of mammals. It is used in the manufacture of food and drink products and sold as a nutritional supplement for its analgesic and antidepressant effects. It is a direct precursor to the neuromodulator phenethylamine, a commonly used dietary supplement. As an essential amino acid, phenylalanine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanogenesis
Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. In inorganic cyanides, the cyanide group is present as the anion . Soluble salts such as sodium cyanide (NaCN) and potassium cyanide (KCN) are highly toxic. Hydrocyanic acid, also known as hydrogen cyanide, or HCN, is a highly volatile liquid that is produced on a large scale industrially. It is obtained by acidification of cyanide salts. Organic cyanides are usually called nitriles. In nitriles, the group is linked by a covalent bond to carbon. For example, in acetonitrile (), the cyanide group is bonded to methyl (). Although nitriles generally do not release cyanide ions, the cyanohydrins do and are thus rather toxic. Bonding The cyanide ion is isoelectronic with carbon monoxide and wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perianth
The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower, and structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepals when called a perigone. The term ''perianth'' is derived from Greek περί (, "around") and άνθος (, "flower"), while ''perigonium'' is derived from περί () and γόνος (, "seed, sex organs"). In the mosses and liverworts (Marchantiophyta), the perianth is the sterile tubelike tissue that surrounds the female reproductive structure (or developing sporophyte). Flowering plants In flowering plants, the perianth may be described as being either dichlamydeous/heterochlamydeous in which the calyx and corolla are clearly separate, or homochlamydeous, in which they are indistinguishable (and the sepals and petals are collectively referred to as tepals). When the perianth is in two whorls, it is described as biseriate. While the ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phloem
Phloem (, ) is the living tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This transport process is called translocation. In trees, the phloem is the innermost layer of the bark, hence the name, derived from the Ancient Greek word (''phloiós''), meaning "bark". The term was introduced by Carl Nägeli in 1858. Structure Phloem tissue consists of conducting cells, generally called sieve elements, parenchyma cells, including both specialized companion cells or albuminous cells and unspecialized cells and supportive cells, such as fibres and sclereids. Conducting cells (sieve elements) Sieve elements are the type of cell that are responsible for transporting sugars throughout the plant. At maturity they lack a nucleus and have very few organelles, so they rely on companion cells or albuminous cells for most of their metabolic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellagic Acid
Ellagic acid is a polyphenol found in numerous fruits and vegetables. It is the dilactone of hexahydroxydiphenic acid. Name The name comes from the French term ''acide ellagique'', from the word ''galle'' spelled backwards because it can be obtained from ''noix de galle'' (galls), and to distinguish it from ''acide gallique'' (gallic acid). The molecule structure resembles to that of two gallic acid molecules being assembled "head to tail" and bound together by a C–C bond (as in biphenyl, or in diphenic acid) and two lactone links (cyclic carboxylic esters). Metabolism Biosynthesis Plants produce ellagic acid from hydrolysis of tannins such as ellagitannin and geraniin. Biodegradation Urolithins are gut flora human metabolites of dietary ellagic acid derivatives. Ellagic acid has low bioavailability, with 90% remaining unabsorbed from the intestines until metabolized by microflora to the more bioavailable urolintins. History Ellagic acid was first discovered b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamamelidales
Hamamelidales is an order of flowering plants formerly accepted in a number of systems of plant taxonomy, including the Cronquist system published in 1968 and 1988. The order is not currently accepted in the Angiosperm Phylogeny Group III system of plant taxonomy, the most widely accepted system as molecular systematic studies have suggested that these families are not closely related to each other. The APG II system (2003) assigns them to several different orders: Hamamelidaceae and Cercidiphyllaceae to Saxifragales, Eupteleaceae to Ranunculales, Platanaceae to Proteales, and Myrothamnaceae to Gunnerales. Additional studies of the chloroplast genome have since confirmed that the families moved into the Saxigragales are closely related. The Cronquist system (1981) included the order in subclass Hamamelidae with the circumscription: * order Hamamelidales *: family Hamamelidaceae, now in order Saxifragales *: family Cercidiphyllaceae, now in order Saxifragales *: family Eupteleac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armen Takhtajan
Armen Leonovich Takhtajan or Takhtajian ( hy, Արմեն Լևոնի Թախտաջյան; russian: Армен Леонович Тахтаджян; surname also transliterated Takhtadjan, Takhtadzhi︠a︡n or Takhtadzhian, pronounced takh-tuh-JAHN; 10 June 1910 – 13 November 2009), was a Soviet- Armenian botanist, one of the most important figures in 20th century plant evolution and systematics and biogeography. His other interests included morphology of flowering plants, paleobotany, and the flora of the Caucasus. He was one of the most influential taxonomists of the latter twentieth century. Life Family Takhtajan was born in Shushi, Russian Empire, present-day disputed Nagorno-Karabakh, on 10 June 1910, to a family of Armenian intellectuals. His grandfather Meliksan Takhtadzhyan Petrovich had been born in Trabzon, Ottoman Empire and was educated in Italy, on the island of San Lazzaro degli Armeni, an Armenian enclave, spoke many languages and worked as a journ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
