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Rhizosphere (ecology)
The rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome. Soil pores in the rhizosphere can contain many bacteria and other microorganisms that feed on sloughed-off plant cells, termed ''rhizodeposition'', and the proteins and sugars released by roots, termed root exudates. This symbiosis leads to more complex interactions, influencing plant growth and competition for resources. Much of the nutrient cycling and disease suppression by antibiotics required by plants occurs immediately adjacent to roots due to root exudates and metabolic products of symbiotic and pathogenic communities of microorganisms. The rhizosphere also provides space to produce allelochemicals to control neighbours and relatives. The ''rhizoplane'' refers to the root surface including its associated soil particles which closely interact with each other. The plant-soil feedback loop and other ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Some Rhizosphere Processes In The Soil
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Some may refer to: *''some'', an English word used as a determiner and pronoun; see use of ''some'' *The term associated with the existential quantifier *"Some", a song by Built to Spill from their 1994 album ''There's Nothing Wrong with Love'' *Socialist-oriented market economy, the Vietnamese economic system occasionally abbreviated SOME *Social market economy, the German socioeconomic model abbreviated SOME *So Others Might Eat (SOME), a Washington, D.C.–based non-profit organization *SoMe, short for social media * ''Some'' (film), a 24 film * "Some" (song), a duet by Junggigo and Soyou *Some & Any, German pop duo See also * Some (surname) Some is a surname. Notable people with this surname include: * Thomas Some (divine) (1509/10–c. 1553), English Protestant divine * Thomas Some (died 1649), Church of England priest, Canon of Windsor * Belouis Some Belouis Some (born Nevil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Pressure
Evolutionary pressure, selective pressure or selection pressure is exerted by factors that reduce or increase reproductive success in a portion of a population, driving natural selection. It is a quantitative description of the amount of change occurring in processes investigated by evolutionary biology, but the formal concept is often extended to other areas of research. In population genetics, selective pressure is usually expressed as a selection coefficient. Amino acids selective pressure It has been shown that putting an amino acid bio-synthesizing gene like ''HIS4'' gene under amino acid selective pressure in yeast causes enhancement of expression of adjacent genes which is due to the transcriptional co-regulation of two adjacent genes in Eukaryota. Antibiotic resistance Drug resistance in bacteria is an example of an outcome of natural selection. When a drug is used on a species of bacteria, those that cannot resist die and do not produce offspring, while those that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lignin
Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily. Chemically, lignins are polymers made by cross-linking phenolic precursors. History Lignin was first mentioned in 1813 by the Swiss botanist A. P. de Candolle, who described it as a fibrous, tasteless material, insoluble in water and alcohol but soluble in weak alkaline solutions, and which can be precipitated from solution using acid. He named the substance "lignine", which is derived from the Latin word '' lignum'', meaning wood. It is one of the most abundant organic polymers on Earth, exceeded only by cellulose and chitin. Lignin constitutes 30% of terrestrial non-fossil organic carbon on Earth, and 20 to 35% of the dry mass of wood. Lignin is present in red algae, which suggest that the common ancestor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenol
Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it requires careful handling because it can cause chemical burns. It is acutely toxic and is considered a health hazard. Phenol was first extracted from coal tar, but today is produced on a large scale (about 7 million tonnes a year) from petroleum-derived feedstocks. It is an important industrial commodity as a precursor to many materials and useful compounds, and is a liquid when manufactured. It is primarily used to synthesize plastics and related materials. Phenol and its chemical derivatives are essential for production of polycarbonates, epoxies, explosives such as picric acid, Bakelite, nylon, detergents, herbicides such as phenoxy herbicides, and numerous pharmaceuti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tomato Varieties
There are more than 10,000 tomato varieties available. __NOTOC__ Table of tomatoes See also * Lists of cultivars * List of tomato dishes Notes # ::Some tomato cultivars will be marked with disease resistance codes, signifying that the plant is immune to a certain disease shown below: ::*A — Alternaria stem canker ::*F — Fusarium wilt ::*FF — Fusarium races 1 and 2 ::*FFF — Fusarium races 1, 2 and 3 ::*N — Nematodes ::*T — Tobacco mosaic virus ::*St — Stemphylium gray leaf spot ::*V — Verticillium wilt Verticillium wilt is a wilt disease affecting over 350 species of eudicot plants. It is caused by six species of '' Verticillium'' fungi: ''V. dahliae'', ''V. albo-atrum'', ''V. longisporum'', ''V. nubilum'', ''V. theobr ... References External links Non-profit discussion forums for tomato growers with special emphasis on heirloom varieties {{DEFAULTSORT:Tomato Cultivars Lists of cultivars * Tomatoes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyglycolide
Polyglycolide or poly(glycolic acid) (PGA), also spelled as polyglycolic acid, is a biodegradable, thermoplastic polymer and the simplest linear, aliphatic polyester. It can be prepared starting from glycolic acid by means of polycondensation or ring-opening polymerization. PGA has been known since 1954 as a tough fiber-forming polymer. Owing to its hydrolytic instability, however, its use was slow to develop. Polyglycolide and its copolymers ( poly(lactic-''co''-glycolic acid) with lactic acid, poly(glycolide-''co''-caprolactone) with ε-caprolactone and poly (glycolide-''co''-trimethylene carbonate) with trimethylene carbonate) are widely used as a material for the synthesis of absorbable sutures and are being evaluated in the biomedical field. Physical properties Polyglycolide has a glass transition temperature between 35 and 40 °C and a melting point in the range of 225 to 230 °C. PGA also exhibits an elevated degree of crystallinity, around 45–55%, thus r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polysaccharides
Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with water (hydrolysis) using amylase enzymes as catalyst, which produces constituent sugars (monosaccharides or oligosaccharides). They range in structure from linear to highly branched. Examples include storage polysaccharides such as starch, glycogen and galactogen and structural polysaccharides such as hemicellulose and chitin. Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure, these macromolecules can have distinct properties from their monosaccharide building blocks. They may be amorphous or even insoluble in water. When all the monosaccharides in a polysaccharide are the same type, the polysaccharide is called a homopolysaccharide or homoglycan, but when more t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Root Exudate
Plant root exudates are fluids emitted through the roots of plants. These secretions influence the rhizosphere around the roots to inhibit harmful microbes and promote the growth of self and kin plants. Plant root systems can grow to be complex due to a variety of species and microorganisms existing in a common soil. Plants have adapted to respond to the soil conditions and presence of microorganism, microbes through various mechanisms, one of which is the secretion of root exudates. This secretion allows plants to largely influence the rhizosphere as well as the organisms that exist within it. The contents of exudates and the amount of substance released is reliant on multiple factors, including the root system architecture, presence of harmful microbes, and metal toxicity. The species of the plant as well as its developmental stage can also influence the chemical mixture that is released through exudates. The contents may include ions, compounds of carbon, carbon-based compounds, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbohydrate
A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' may differ). This formula does not imply direct covalent bonding between hydrogen and oxygen atoms; for example, in , hydrogen is covalently bonded to carbon, not oxygen. While the 2:1 hydrogen-to-oxygen ratio is characteristic of many carbohydrates, exceptions exist. For instance, uronic acids and deoxy-sugars like fucose deviate from this precise stoichiometric definition. Conversely, some compounds conforming to this definition, such as formaldehyde and acetic acid, are not classified as carbohydrates. The term is predominantly used in biochemistry, functioning as a synonym for saccharide (), a group that includes sugars, starch, and cellulose. The saccharides are divided into four chemical groups: monosaccharides, disaccharides, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulk Soil
Bulk soil is soil outside the rhizosphere that is not penetrated by plant roots. The bulk soil is like an ecosystem, it is made up of many things such as: nutrients, ions, soil particles, and root exudates. There are many different interactions that occur between all the members of the bulk soil. Natural organic compounds are much lower in bulk soil than in the rhizosphere. Furthermore, bulk soil inhabitants are generally smaller than identical species in the rhizosphere. The main two aspects of bulk soil are its chemistry and microbial community composition. Chemistry of bulk soil Soil is made up of layers called soil horizons, these make up a vertical soil profile. There are five master horizons O, A, E, B, and C. The O horizon contains organic matter, A is considered the topsoil, E is present or absent depending on the type of soil and conditions, B is the subsoil, and C is unconsolidated rock. There are many chemical interactions and properties that are in all the soil. Chem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Acid
An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group –COOH. Sulfonic acids, containing the group –SO2OH, are relatively stronger acids. Alcohols, with –OH, can act as acids but they are usually very weak. The relative stability of the conjugate base of the acid determines its acidity. Other groups can also confer acidity, usually weakly: the thiol group –SH, the enol group, and the phenol group. In biological systems, organic compounds containing these groups are generally referred to as organic acids. A few common examples include: * Lactic acid * Acetic acid * Formic acid * Citric acid * Oxalic acid * Uric acid * Malic acid * Tartaric acid * Butyric acid * Folic acid Characteristics In general, organic acids are weak acids and do not dissociate completely in water, whereas the strong mineral acids do. Lower molecular mass organ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Root Exudates
Plant root exudates are fluids emitted through the roots of plants. These secretions influence the rhizosphere around the roots to inhibit harmful microbes and promote the growth of self and kin plants. Plant root systems can grow to be complex due to a variety of species and microorganisms existing in a common soil. Plants have adapted to respond to the soil conditions and presence of microbes through various mechanisms, one of which is the secretion of root exudates. This secretion allows plants to largely influence the rhizosphere as well as the organisms that exist within it. The contents of exudates and the amount of substance released is reliant on multiple factors, including the root system architecture, presence of harmful microbes, and metal toxicity. The species of the plant as well as its developmental stage can also influence the chemical mixture that is released through exudates. The contents may include ions, carbon-based compounds, amino acids, sterols, and many oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
