42-554: [REDACTED] Look up stylo in Wiktionary, the free dictionary. Stylo may refer to: Stylosanthes , A widely cultivated plant genus native to the Americas Barratts Shoes A UK brand of footwear "Stylo" (song) , a single from British virtual band Gorillaz Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with
84-460: A cyanobiont (cyanobacteria such as Nostoc ) which fix nitrogen for them: Some symbiotic relationships involving agriculturally-important plants are: A method for nitrogen fixation was first described by Henry Cavendish in 1784 using electric arcs reacting nitrogen and oxygen in air. This method was implemented in the Birkeland–Eyde process of 1903. The fixation of nitrogen by lightning
126-399: A nitrogenase enzyme. The overall reaction for BNF is: N 2 + 16ATP + 16H 2 O + 8e + 8H → 2NH 3 +H 2 + 16ADP + 16P i The process is coupled to the hydrolysis of 16 equivalents of ATP and is accompanied by the co-formation of one equivalent of H 2 . The conversion of N 2 into ammonia occurs at a metal cluster called FeMoco , an abbreviation for
168-543: A critical threshold. The specialized heterocyst cell is necessary for the performance of nitrogenase as a result of its sensitivity to ambient oxygen. Nitrogenase consist of two proteins, a catalytic iron-dependent protein, commonly referred to as MoFe protein and a reducing iron-only protein (Fe protein). There are three different iron dependent proteins, molybdenum -dependent, vanadium -dependent, and iron -only, with all three nitrogenase protein variations containing an iron protein component. Molybdenum-dependent nitrogenase
210-447: A low nitrogen content, has been shown to host a diazotrophic community. The bacteria enrich the wood substrate with nitrogen through fixation, thus enabling deadwood decomposition by fungi. Nitrogenases are rapidly degraded by oxygen. For this reason, many bacteria cease production of the enzyme in the presence of oxygen. Many nitrogen-fixing organisms exist only in anaerobic conditions, respiring to draw down oxygen levels, or binding
252-457: A low woody shrub to 1.5 m, while others such as S. humilis will grow as a herbaceous shrub but can adopt a prostrate growth form and thrive under high grazing pressure. Taxonomy of the genus remains unsettled and controversial, with various authors favouring between 25 and 42 species, with at least 40 additional synonyms. The taxonomy is complicated by the existence of numerous natural tetraploid and hybrid populations. Species within
294-424: A new era of soil science ." In 1901, Beijerinck showed that Azotobacter chroococcum was able to fix atmospheric nitrogen. This was the first species of the azotobacter genus, so-named by him. It is also the first known diazotroph , species that use diatomic nitrogen as a step in the complete nitrogen cycle . Biological nitrogen fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by
336-746: A nitrogen input into low input or organic cropping systems. Species are used as fallow species in Peru , Africa and Australia . S. hamata used for intercropping with grain crops in India and Africa with yield increases up to 25%. Stylosanthes species have been used for land reclamation, soil stabilization and soil regeneration work because of their drought resistance, ability to restore soil fertility, improve soil physical properties and provide permanent vegetation cover. Despite their ability to dramatically improve productivity in grazing lands, Stylosanthes can also cause problems. Stylosanthes can dominate pasture at
378-451: A second metal (usually molybdenum , but sometimes vanadium ). Some nitrogen-fixing bacteria have symbiotic relationships with plants , especially legumes , mosses and aquatic ferns such as Azolla . Looser non-symbiotic relationships between diazotrophs and plants are often referred to as associative, as seen in nitrogen fixation on rice roots. Nitrogen fixation occurs between some termites and fungi . It occurs naturally in
420-443: Is a chemical process by which molecular dinitrogen ( N 2 ) is converted into ammonia ( NH 3 ). It occurs both biologically and abiologically in chemical industries . Biological nitrogen fixation or diazotrophy is catalyzed by enzymes called nitrogenases . These enzyme complexes are encoded by the Nif genes (or Nif homologs ) and contain iron , often with
462-624: Is a genus of flowering plants in the legume family Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic Pterocarpus clade of the Dalbergieae . The common name pencilflower is sometimes used for plants in this genus. The genus is characterised by trifoliate leaves and small yellow flowers Species may be annual or perennial and morphology varies between species as well as within species in response to grazing pressure. Some species such as S. scabra grow as
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#1732891947729504-408: Is a required precursor to fertilizers , explosives , and other products. The Haber process requires high pressures (around 200 atm) and high temperatures (at least 400 °C), which are routine conditions for industrial catalysis. This process uses natural gas as a hydrogen source and air as a nitrogen source. The ammonia product has resulted in an intensification of nitrogen fertilizer globally and
546-532: Is a very similar natural occurring process. The possibility that atmospheric nitrogen reacts with certain chemicals was first observed by Desfosses in 1828. He observed that mixtures of alkali metal oxides and carbon react with nitrogen at high temperatures. With the use of barium carbonate as starting material, the first commercial process became available in the 1860s, developed by Margueritte and Sourdeval. The resulting barium cyanide reacts with steam, yielding ammonia. In 1898 Frank and Caro developed what
588-447: Is also noted for its ability to extract phosphorus from soils where it is not available to other species. Seeds are hard and long lived leading to high soil seed banks and rapid recovery following fire or heavy grazing. Seed survives passage through the gut of grazing animals and is dispersed widely in this manner allowing for rapid dispersal. Many species are adapted to hot, dry climates and are drought resistant. These traits have made
630-562: Is credited with supporting the expansion of the human population from around 2 billion in the early 20th century to roughly 8 billion people now. Much research has been conducted on the discovery of catalysts for nitrogen fixation, often with the goal of lowering energy requirements. However, such research has thus far failed to approach the efficiency and ease of the Haber process. Many compounds react with atmospheric nitrogen to give dinitrogen complexes . The first dinitrogen complex to be reported
672-442: Is dependent on many factors, including the legume and air and soil conditions. For example, nitrogen fixation by red clover can range from 50 to 200 lb/acre (56 to 224 kg/ha). The ability to fix nitrogen in nodules is present in actinorhizal plants such as alder and bayberry , with the help of Frankia bacteria. They are found in 25 genera in the orders Cucurbitales , Fagales and Rosales , which together with
714-595: Is endemic to Tropical Africa, from Tanzania to Senegal . The putative species S. sundaica , has a range that encompasses Malesia but is considered by most authors to be an adventive polypoliod variety of S. humilis . Ecological range extends from savanna and thorn scrub to tropical forest and montane forests. The following species are accepted: Species within the genus have many properties that make them valuable forage species. They are capable of nitrogen fixation and are capable of improving soil fertility in addition to providing high protein stock feed. The genus
756-408: Is genetically regulated, and the activity of the protein complex is dependent on ambient oxygen concentrations, and intra- and extracellular concentrations of ammonia and oxidized nitrogen species (nitrate and nitrite). Additionally, the combined concentrations of both ammonium and nitrate are thought to inhibit N Fix , specifically when intracellular concentrations of 2- oxoglutarate (2-OG) exceed
798-561: Is known as the Frank–Caro process to fix nitrogen in the form of calcium cyanamide . The process was eclipsed by the Haber process , which was discovered in 1909. The dominant industrial method for producing ammonia is the Haber process also known as the Haber-Bosch process. Fertilizer production is now the largest source of human-produced fixed nitrogen in the terrestrial ecosystem . Ammonia
840-791: Is no conclusive agreement on which form of nitrogenase arose first. Diazotrophs are widespread within domain Bacteria including cyanobacteria (e.g. the highly significant Trichodesmium and Cyanothece ), green sulfur bacteria , purple sulfur bacteria , Azotobacteraceae , rhizobia and Frankia . Several obligately anaerobic bacteria fix nitrogen including many (but not all) Clostridium spp. Some archaea such as Methanosarcina acetivorans also fix nitrogen, and several other methanogenic taxa , are significant contributors to nitrogen fixation in oxygen-deficient soils. Cyanobacteria , commonly known as blue-green algae, inhabit nearly all illuminated environments on Earth and play key roles in
882-590: Is the most commonly present nitrogenase. The different types of nitrogenase can be determined by the specific iron protein component. Nitrogenase is highly conserved. Gene expression through DNA sequencing can distinguish which protein complex is present in the microorganism and potentially being expressed. Most frequently, the nif H gene is used to identify the presence of molybdenum-dependent nitrogenase, followed by closely related nitrogenase reductases (component II) vnf H and anf H representing vanadium-dependent and iron-only nitrogenase, respectively. In studying
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#1732891947729924-480: The Fabales form a nitrogen-fixing clade of eurosids . The ability to fix nitrogen is not universally present in these families. For example, of 122 Rosaceae genera, only four fix nitrogen. Fabales were the first lineage to branch off this nitrogen-fixing clade; thus, the ability to fix nitrogen may be plesiomorphic and subsequently lost in most descendants of the original nitrogen-fixing plant; however, it may be that
966-414: The air by means of NO x production by lightning . Nitrogen fixation is essential to life on Earth because fixed inorganic nitrogen compounds are required for the biosynthesis of all nitrogen-containing organic compounds such as amino acids , polypeptides and proteins , nucleoside triphosphates and nucleic acids . As part of the nitrogen cycle , it is essential for soil fertility and
1008-690: The amount of nitrogen fixed in the ocean is at least as much as that on land. The colonial marine cyanobacterium Trichodesmium is thought to fix nitrogen on such a scale that it accounts for almost half of the nitrogen fixation in marine systems globally. Marine surface lichens and non-photosynthetic bacteria belonging in Proteobacteria and Planctomycetes fixate significant atmospheric nitrogen. Species of nitrogen fixing cyanobacteria in fresh waters include: Aphanizomenon and Dolichospermum (previously Anabaena). Such species have specialized cells called heterocytes , in which nitrogen fixation occurs via
1050-409: The basic genetic and physiological requirements were present in an incipient state in the most recent common ancestors of all these plants, but only evolved to full function in some of them. In addition, Trema ( Parasponia ), a tropical genus in the family Cannabaceae , is unusually able to interact with rhizobia and form nitrogen-fixing nodules. Some other plants live in association with
1092-556: The carbon and nitrogen cycle of the biosphere . In general, cyanobacteria can use various inorganic and organic sources of combined nitrogen, such as nitrate , nitrite , ammonium , urea , or some amino acids . Several cyanobacteria strains are also capable of diazotrophic growth, an ability that may have been present in their last common ancestor in the Archean eon. Nitrogen fixation not only naturally occurs in soils but also aquatic systems, including both freshwater and marine. Indeed,
1134-498: The ecology and evolution of nitrogen-fixing bacteria , the nifH gene is the biomarker most widely used. nif H has two similar genes anf H and vnfH that also encode for the nitrogenase reductase component of the nitrogenase complex. Nitrogenase is thought to have evolved sometime between 1.5-2.2 billion years ago (Ga), although some isotopic support showing nitrogenase evolution as early as around 3.2 Ga. Nitrogenase appears to have evolved from maturase -like proteins, although
1176-774: The expense of grass which can lead to problems because the plants provides less protection from erosion than grass. Stylosanthes dominance can also lead to soil acidification , as soil nitrate levels build up and are then leached down the soil profile. Stylosanthes species are considered invasive species and environmental weeds in Australia , Taiwan , the Pacific Islands and Hawaii . Many Stylosanthes species are susceptible to anthracnose fungus ( Colletotrichum gloeosporioides ) which retards growth and seed development, and this had led to numerous commercial cultivars being abandoned. Nitrogen fixation Nitrogen fixation
1218-410: The function of the preceding protein is currently unknown. Nitrogenase has three different forms ( Nif, Anf, and Vnf ) that correspond with the metal found in the active site of the protein (Molybdenum, Iron, and Vanadium respectively). Marine metal abundances over Earth’s geologic timeline are thought to have driven the relative abundance of which form of nitrogenase was most common. Currently, there
1260-529: The genus fall within two subgenera: Styposanthes and Stylosanthes . Styposanthes possess a small rudimentary secondary floral axis , which is absent from Stylosanthes . Stylosanthes is closely related to the peanut genus Arachis . All except two species of the genus are native to the Americas. S. fruticosa has a native range that extends from South Africa to Ethiopia , across Arabian Peninsula to Pakistan , India and Sri Lanka and S. erecta
1302-468: The genus the world’s most widely used tropical pasture legume. Stylosanthes has been introduced across the tropical world as a pasture species. Its most important use has been in Australia where over a million hectares of primarily native pasture have been oversown with Stylosanthes species; primarily S. hamata , S. scabra and S. humilis This can lead to a ten-fold increase in productivity, though 2–3 fold increases are normal. Stylosanthes are
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1344-406: The growth of terrestrial and semiaquatic vegetations , upon which all consumers of those ecosystems rely for biomass . Nitrogen fixation is thus crucial to the food security of human societies in sustaining agricultural yields (especially staple crops ), livestock feeds ( forage or fodder ) and fishery (both wild and farmed ) harvests . It is also indirectly relevant to
1386-544: The iron- molybdenum cofactor. The mechanism proceeds via a series of protonation and reduction steps wherein the FeMoco active site hydrogenates the N 2 substrate. In free-living diazotrophs , nitrogenase-generated ammonia is assimilated into glutamate through the glutamine synthetase /glutamate synthase pathway. The microbial nif genes required for nitrogen fixation are widely distributed in diverse environments. For example, decomposing wood, which generally has
1428-492: The manufacture of all nitrogenous industrial products , which include fertilizers , pharmaceuticals , textiles , dyes and explosives . Biological nitrogen fixation was discovered by Jean-Baptiste Boussingault in 1838. Later, in 1880, the process by which it happens was discovered by German agronomist Hermann Hellriegel and Hermann Wilfarth [ de ] and was fully described by Dutch microbiologist Martinus Beijerinck . "The protracted investigations of
1470-616: The most important forage legumes in South America and the most important pasture legumes of tropical India . Stylosanthes are also important forage species in tropical Africa. Stylosanthes are important green manure species in West and Central Africa , primarily S. guianensis and S. hamata , and species are planted and harvested for commercial leaf meal production for poultry and pig feed in China and India . The genus has also been used as
1512-473: The nitrogenase enzyme. One type of organelle can turn nitrogen gas into a biologically available form. This nitroplast was discovered in algae . Plants that contribute to nitrogen fixation include those of the legume family — Fabaceae — with taxa such as kudzu , clover , soybean , alfalfa , lupin , peanut and rooibos . They contain symbiotic rhizobia bacteria within nodules in their root systems , producing nitrogen compounds that help
1554-409: The oxygen with a protein such as leghemoglobin . Atmospheric nitrogen is inaccessible to most organisms, because its triple covalent bond is very strong. Most take up fixed nitrogen from various sources. For every 100 atoms of carbon, roughly 2 to 20 atoms of nitrogen are assimilated. The atomic ratio of carbon (C) : nitrogen (N) : phosphorus (P) observed on average in planktonic biomass
1596-475: The plant to grow and compete with other plants. When the plant dies, the fixed nitrogen is released, making it available to other plants; this helps to fertilize the soil . The great majority of legumes have this association, but a few genera (e.g., Styphnolobium ) do not. In many traditional farming practices, fields are rotated through various types of crops, which usually include one consisting mainly or entirely of clover . Fixation efficiency in soil
1638-462: The relation of plants to the acquisition of nitrogen begun by de Saussure , Ville , Lawes , Gilbert and others, and culminated in the discovery of symbiotic fixation by Hellriegel and Wilfarth in 1887." "Experiments by Bossingault in 1855 and Pugh, Gilbert & Lawes in 1887 had shown that nitrogen did not enter the plant directly. The discovery of the role of nitrogen fixing bacteria by Herman Hellriegel and Herman Wilfarth in 1886-1888 would open
1680-466: The title Stylo . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Stylo&oldid=908642535 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Stylosanthes See text Stylosanthes
1722-767: Was Ru(NH 3 ) 5 ( N 2 ) . Some soluble complexes do catalyze nitrogen fixation. Nitrogen can be fixed by lightning converting nitrogen gas ( N 2 ) and oxygen gas ( O 2 ) in the atmosphere into NO x ( nitrogen oxides ). The N 2 molecule is highly stable and nonreactive due to the triple bond between the nitrogen atoms. Lightning produces enough energy and heat to break this bond allowing nitrogen atoms to react with oxygen, forming NO x . These compounds cannot be used by plants, but as this molecule cools, it reacts with oxygen to form NO 2 , which in turn reacts with water to produce HNO 2 ( nitrous acid ) or HNO 3 ( nitric acid ). When these acids seep into
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1764-422: Was originally described by Alfred Redfield, who determined the stoichiometric relationship between C:N:P atoms, The Redfield Ratio, to be 106:16:1. The protein complex nitrogenase is responsible for catalyzing the reduction of nitrogen gas (N 2 ) to ammonia (NH 3 ). In cyanobacteria , this enzyme system is housed in a specialized cell called the heterocyst . The production of the nitrogenase complex
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