A plant hormone. That β IAA. "In the root, stem and other cutting-edge generation, young leaves, buds, tender fruit, too. Only from the top down-side transport plants conduction. Can promote the growth of buds and stems, roots and fruit development . generally low concentration to promote growth, high concentrations inhibit the growth or even kill the plant.
Translated by Google
No. 2
IAA (auxin) are a class of aromatic ring containing an unsaturated side chain of the acetic acid and a source of hormones, the English referred iaa, internationally, is indole acetic acid (iaa). 4 - chloro-iaa, 5 - hydroxy-iaa, naphthylacetate (naa), indole butyric acid as the class of auxin. Xie 1872 Poland horticulturist with Chomsky on apical control of root elongation zone growth were made; later Darwin and Son? Grass coleoptile phototropism was studied. Winter 1928, first isolated coleoptile bending that causes the chemical messenger substances, called growth hormone. In 1934, Keg, etc. make sure it is indole acetic acid, which often customary to auxin IAA as a synonym. Auxin in the expansion of young leaves and apical meristem in the synthesis of long-distance transport through the phloem, the top down to the base of the accumulation. Auxin is also able to produce roots, bottom-up transport. Auxin in plants is through a series of intermediate products of tryptophan formed. The main way is through the indole acetaldehyde. Indole acetaldehyde can be oxidized by the deamination of tryptophan into indole pyruvate formed after the decarboxylation, it can be the first decarboxylation of tryptophan into serotonin formed after the oxidative deamination. And then re-oxidation of acetaldehyde into indole-indole acetic acid. Another possible pathway is through the indole of tryptophan into indole acetic acid acetonitrile. Indole acetic acid in plants can be combined with other substances to lose activity, such as the combination of indole with acetyl aspartate aspartic acid, and inositol together to form IAA inositol, and glucose combined into glucoside, and indole acetic acid into the protein binding - protein complexes and so on. Bound IAA can often account for indole acetic acid in plants 50 to 90%, auxin in the plant tissue may be one stored in the form of their hydrolysis can produce free indole acetic acid. Prevalent in plant tissue indoleacetic acid oxidase can be indole acetic acid oxidation and decomposition. There are many physiological effects of auxin, which with its concentration. Low concentrations can promote the growth of high concentrations inhibited growth, and even to plant death, and its ability to induce the inhibition of ethylene formation. The physiological effects of auxin in two levels. At the cellular level, auxin can stimulate the cambium cell division; stimulate branch cell elongation, inhibition of root growth; promote xylem and phloem cell differentiation and promote rooting cuttings, regulate morphogenesis of callus. In organs and whole plant level, auxin from seedling to fruit maturation are working. Auxin control seedlings reversibility of red light inhibition of hypocotyl elongation; when indole acetic acid transferred to the lower side branches that produce geotropic branches; when indole acetic acid transferred to the backlight side, the branches, the branches of the phototropism ; IAA caused the top edge; delay leaf senescence; applied auxin in the inhibition of leaf shedding, while the application of auxin at the abscission layer to promote off near shaft; auxin promote flowering, fruit development induced by single-sex, delayed fruit ripening. After the application of IAA led to a specific messenger ribonucleic acid (mrna) sequences occur, thus changing the protein synthesis. IAA treatment also changed the cell wall of flexibility to enable cell growth to proceed. The dual nature of the physiological role of plant growth: Low concentration to promote growth, higher concentrations inhibited growth. Plant organs, the optimal concentration of auxin requirements are different. The optimum concentration of about root 10e-10mol / l, the optimal concentration of about bud 10e-8mol / l, the concentration of about stem 10e-5mol / l. Often used in the production of auxin analogues (such as Naphthylacetate ,2,4-d, etc.) to regulate the production of plant growth, such as bean sprouts is to use when appropriate to deal with the concentration of stem growth of bean sprouts, the results are suppressed root and shoot , while the hypocotyl develops into the stem is developed. The top edge of plant stem growth by the plant growth hormone auxin transport characteristics and physiological role of the duality of the two factors, the plant is to produce stem buds the most active parts of auxin, but auxin produced by the terminal bud at the concentration of active transport and by constantly transported to the stem, so the terminal bud itself is not high auxin concentration, while the concentration in the young stems are higher, best suited to stem the growth inhibition of bud there. The closer the location of the terminal bud the higher the concentration of auxin, the stronger the inhibition of lateral bud, which is a lot of tall trees form a pagoda-shaped plant causes. But not all plants with a strong apical dominance, and some shrubs plants bud development for some time after the beginning of degradation, or even shrink, lose their top edge, so the shrub is not a pagoda-shaped tree. Due to the high concentrations of auxin can inhibit the role of plant growth, so the production of high concentrations of auxin can also be used as a herbicide analogues, especially for dicotyledonous weeds is very effective. Auxin analogs :2,4-d. Auxin in plants because there is a very small number, in order to control plant growth, it was discovered that the growth hormone analogues, which have a similar effect, and auxin production and can now has been widely applied to agricultural production. Earth's gravity on auxin distribution: The growth of stem and root gravitropism sly growth is caused by the Earth's gravity, because gravity causes the uneven distribution of auxin in the stem of the near-side distribution of many sly side of the distribution less. Because the optimal concentration of auxin stem the high side of the stem near ground some of its more auxin can promote, so near-side growing faster than the sly side, maintaining the upward growth of stems; on the root, since the root optimal concentration of auxin is very low, near to the side a bit more on the root cell growth but inhibit the growth of so near to the side to side than the sly slow growth, maintaining the growth of root geotropism. Without gravity, the root is not necessarily down long. In weightlessness on plant growth: Gravitropic root growth and stem growth is to have a sly gravity-induced, is due to induced gravity caused due to uneven distribution of auxin. Weightlessness in space, due to loss of gravity, so the growth of the stem loses its sly nature, lost gravitropic root growth characteristics. However, top stem growth advantage is still there, the polarity of auxin transport from the influence of gravity. Auxin found: Auxin was the first plant hormone discovered. 1880 Darwin, the British research in the use of canary grass Yi phototropism of plants found on one-way illuminated coleoptile, coleoptile phototropism cause bending. Trim the tip of the coleoptile or opaque foil cap covering the coleoptile, light exposure does not occur with unilateral phototropic bending. Thus, Darwin argued coleoptile resulted in a unilateral light moving down the material, causing the backlight coleoptile to the smooth surface and the growth speed is different from the coleoptile to bend light. 1928 Netherlands Derwent to the oat coleoptile tip cut straight and agar blocks, after a period of time, remove the tip of coleoptiles placed in these small pieces of agar to one side of the coleoptile tip, resulting in the side of agar grew faster in the opposite direction of bending. This experiment confirmed that a substance produced by the coleoptile tip spread to the agar, the place came alive again when the coleoptile can be transferred to the lower coleoptile, and to promote lower growth. Then went for the first time produced isolated sheath tip growth-related substances, and named this substance auxin. 1934 Netherlands kogl and others isolated from human urine a compound added to the agar, the same can be induced coleoptile bent, the compound proved to be indole acetic acid. Then kogl and others are also found in plant tissue indole acetic acid (indoleacetie acid called iaa).
Translated by Google
No. 3
Such as indole acetic acid
Translated by Google
Auxin
生长素
IAA (auxin) are a class of aromatic ring containing an unsaturated side chain of the acetic acid and a source of hormones, the English referred to IAA, internationally, is indole acetic acid (IAA). 4 - chloro-IAA, 5 - hydroxy-IAA, naphthylacetic acid (NAA), indole butyric acid as the class of auxin. Xie 1872 Poland horticulturist with Chomsky on apical control of root elongation zone growth were made; was Darwin and his son on the grass coleoptile phototropism was studied. Winter 1928 confirmed the germ of the tip did produce a substance, to control embryo growth. In 1934, the Keg, who isolated from some plants of this substance and named it as indole acetic acid, and therefore used often in the auxin indole acetic acid as a synonym. Auxin in the expansion of young leaves and apical meristem in the synthesis of long-distance transport through the phloem, the top down to the base of the accumulation. Auxin is also able to produce roots, bottom-up transport. Auxin in plants is through a series of intermediate products of tryptophan formed. The main way is through the indole acetaldehyde. Indole acetaldehyde can be oxidized by the deamination of tryptophan into indole pyruvate formed after the decarboxylation, it can be the first decarboxylation of tryptophan into serotonin formed after the oxidative deamination. And then re-oxidation of acetaldehyde into indole-indole acetic acid. Another possible pathway is through the indole of tryptophan into indole acetic acid acetonitrile. Indole acetic acid in plants can be combined with other substances to lose activity, such as the combination of indole with acetyl aspartate aspartic acid, and inositol together to form IAA inositol, and glucose combined into glucoside, and indole acetic acid into the protein binding - protein complexes and so on. Bound IAA can often account for indole acetic acid in plants 50 to 90%, auxin in the plant tissue may be one stored in the form of their hydrolysis can produce free indole acetic acid. Prevalent in plant tissue indoleacetic acid oxidase can be indole acetic acid oxidation and decomposition. There are many physiological effects of auxin, which with its concentration. Low concentrations can promote the growth of high concentrations inhibited growth, and even to plant death, and its ability to induce the inhibition of ethylene formation. The physiological effects of auxin in two levels. At the cellular level, auxin can stimulate the cambium cell division; stimulate branch cell elongation, inhibition of root growth; promote xylem and phloem cell differentiation and promote rooting cuttings, regulate morphogenesis of callus. In organs and whole plant level, auxin from seedling to fruit maturation are working. Auxin control seedlings reversibility of red light inhibition of hypocotyl elongation; when indole acetic acid transferred to the lower side branches that produce geotropic branches; when indole acetic acid transferred to the backlight side, the branches, the branches of the phototropism ; IAA caused the top edge; delay leaf senescence; applied auxin in the inhibition of leaf shedding, while the application of auxin at the abscission layer to promote off near shaft; auxin promote flowering, fruit development induced by single-sex, delayed fruit ripening. After the application of IAA led to a specific messenger RNA (mRNA) sequences occur, thus changing the protein synthesis. IAA treatment also changed the cell wall of flexibility to enable cell growth to proceed. The dual nature of the physiological role of plant growth: Low concentration to promote growth, higher concentrations inhibited growth. Plant organs, the optimal concentration of auxin requirements are different. The optimum concentration of about root 10E-10mol / L, the optimal concentration of about bud 10E-8mol / L, the concentration of about stem 10.3E-5mol / L. Often used in the production of auxin analogues (such as Naphthylacetate ,2,4-D, etc.) to regulate the production of plant growth, such as bean sprouts is to use when appropriate to deal with the concentration of stem growth of bean sprouts, the results are suppressed root and shoot , while the hypocotyl develops into the stem is developed. The top edge of plant stem growth by the plant growth hormone auxin transport characteristics and physiological role of the duality of the two factors, the plant is to produce stem buds the most active parts of auxin, but auxin produced by the terminal bud at the concentration of active transport and by constantly transported to the stem, so the terminal bud itself is not high auxin concentration, while the concentration in the young stems are higher, best suited to stem the growth inhibition of bud there. The closer the location of the terminal bud the higher the concentration of auxin, the stronger the inhibition of lateral bud, which is a lot of tall trees form a pagoda-shaped plant causes. But not all plants with a strong apical dominance, and some shrubs plants bud development for some time after the beginning of degradation, or even shrink, lose their top edge, so the shrub is not a pagoda-shaped tree. Due to the high concentrations of auxin can inhibit the role of plant growth, so the production of high concentrations of auxin can also be used as a herbicide analogues, especially for dicotyledonous weeds is very effective. Auxin analogs :2,4-D. Auxin in plants because there is a very small number, in order to control plant growth, it was discovered that the growth hormone analogues, which have a similar effect, and growth hormone production and can now has been widely applied to agricultural production. The dual nature of the physiological role of plant growth: The growth of stem and root gravitropism sly growth is caused by the Earth's gravity, because gravity causes the uneven distribution of auxin in the stem of the near-side distribution of many sly side of the distribution less. Because the optimal concentration of auxin stem the high side of the stem near ground some of its more auxin can promote, so near-side growing faster than the sly side, maintaining the upward growth of stems; on the root, since the root optimal concentration of auxin is very low, near to the side a bit more on the root cell growth but inhibit the growth of so near to the side to side than the sly slow growth, maintaining the growth of root geotropism. Without gravity, the root is not necessarily down long. In weightlessness on plant growth: Gravitropic root growth and stem growth is to have a sly gravity-induced, is due to induced gravity caused due to uneven distribution of auxin. Weightlessness in space, due to loss of gravity, so the growth of the stem loses its sly nature, lost gravitropic root growth characteristics. However, top stem growth advantage is still there, the polarity of auxin transport from the influence of gravity. Auxin found: Auxin was the first plant hormone discovered. 1880 Darwin, the British research in the use of canary grass Yi phototropism of plants found on one-way illuminated coleoptile, coleoptile phototropism cause bending. Trim the tip of the coleoptile or opaque foil cap covering the coleoptile, light exposure does not occur with unilateral phototropic bending. Thus, Darwin argued coleoptile resulted in a unilateral light moving down the material, causing the backlight coleoptile to the smooth surface and the growth speed is different from the coleoptile to bend light. 1928 Dutch Winter oats to cut coleoptile tip upright on the agar block, after a period of time, remove the tip of coleoptiles placed in these small pieces of agar to one side of the coleoptile tip, resulting in the side of agar grew faster in the opposite direction of bending. This experiment confirmed that a substance produced by the coleoptile tip spread to the agar, the place came alive again when the coleoptile can be transferred to the lower coleoptile, and to promote lower growth. Winter believes that this may be a similar material and animal hormones, named auxin. 1934 Netherlands Kogl and others isolated from human urine a compound added to the agar, the same can be induced coleoptile bent, the compound proved to be indole acetic acid. Kogl, who then also found in plant tissue indole acetic acid (indoleacetie acid referred to as IAA). Summary: the discovery of auxin reflects the basic ideas of scientific research: A. ask questions, make a hypothesis, experimental design, test concluded that B. embodied the principles of experimental design of a single variable; Darwin test a single variable is the cutting edge availability, Winter test whether a single variable is the agar contact coleoptile tip. Auxin metabolism Metabolism of IAA Auxin distribution and transport: 1, the distribution (Distribution) Auxin is widely distributed in plants, almost all of the parts, but not evenly distributed, at a time, the contents of a particular site is affected by several factors influence. Mostly concentrated in parts of vigorous growth (coleoptile, shoot and root tip meristem, cambium, after fertilization of ovary, immature seeds, etc.), while the trend in aging tissues and organs is minimal. 2, Transport (Transport) Polar transport (Polar Transport) Auxin mainly in the apical meristem of plants in the synthesis, and then is transported to various parts of the plant body. Auxin transport in plants is in one direction only from the morphology of plant morphology to the bottom of the top transport, its mode of transport to active transport (requires carriers and ATP) (B) the metabolism of auxin 1. Auxin biosynthesis Synthesis of IAA precursors: tryptophan (tryptophan, Trp). After the side-chain aminotransferase, decarboxylation, oxidation and other reactions. Zinc is a component of tryptophan synthase, zinc deficiency caused by a combination of indole and serine blocked the process of the formation of tryptophan, tryptophan decreased, thus affecting the synthesis of IAA. Often cause the production of apples, pears and other fruit trees leaf disease. 2. The combination of auxin and degradation Auxin in plants, there are two forms: free: with the biological activity, binding type: low activity. In vivo, indole acetic acid and aspartic acid are often combined into indole-acetyl-aspartate ester. Can also be combined with inositol into inositol indole ethanol. And combined into indole acetyl glucose glucosidase. And protein binding into indole acetic acid - protein complexes. Bound auxin type of growth hormone may be stored in the form of a cell, but also to reduce excess growth hormone detoxification methods in the appropriate conditions (pH9-10), which can be transformed into free type, the role of transport shifted to site work. The growth of seeds is the amount of auxin also many, but fully mature, the majority of the bound state hoarded. Bound state exists in the seeds, germination into free type. Auxin degradation (Degradation of IAA) ① enzyme degradation: decomposition of indoleacetic acid oxidase Auxin in plants often in the dynamic balance of synthesis and degradation. Indoleacetic acid oxidase (IAA oxidase) is a hemoglobin containing Fe. After the formation of IAA by the enzyme 3 - hydroxy-indole O-methyl and 3 - methyl indole oxygen. The reaction to the presence of O2, Mn, and one dollar to be cofactors phenol, indole acetic acid oxidase activity before the performance. ② light oxidation and decomposition: X-ray, ultraviolet, visible, have damaging effects on the IAA, the decomposition product is 3 - methyl indole and indole oxidation of aldehydes. But the current mechanism is not clear, in a test tube, some of the plant pigments, such as riboflavin, and so can violaxanthin absorbs blue light, and to promote IAA oxidation and decomposition of light. Auxin in plants exist between the two forms of conversion or indole acetic acid oxidase in the oxidation of IAA in vivo decomposition of plant growth hormone levels are automatically adjusted on the regulation of plant growth is important. The use of growth hormone in agriculture: First, promote the elongation of vegetative organs Auxin (IAA) on the longitudinal growth of the vegetative organs significant role in promoting. Such as buds, stems and roots of three organs, with the concentration, organ elongation increased to maximum, then the optimal concentration of auxin concentration, more than the optimal concentration, organ elongation is inhibited. The optimal concentration of different organs in different stem-side up, shoot second, the lowest root. By the time we can see, the root of the IAA (IAA) the most sensitive to low concentrations can promote root growth, the optimal concentration of 10-10M. Stem and root of the IAA sensitivity lower than the optimal concentration of 10-5M. The sensitivity of the buds in the stems and roots between the optimal concentration of about 10-8M. It can promote the growth of stem and root concentrations tend to inhibit the growth of lateral buds. Second, to promote cell division and differentiation of root With auxin and cytokinin can lead to cell division, and growth hormone alone can lead to cell division. Such as trees, cambium cells recovered from early spring separatist activities of growth hormone produced by the buds arising under the operation. The role of auxins on organogenesis is the most obvious expression in the promotion and growth of the root primordia. Seedling cuttings produced adventitious roots at its base, on the woody plants, the main by the new secondary phloem tissue differentiation, but can also be differentiated into other tissues such as cambium, vascular ray, and pith. Indole butyric acid (IBA) rooting in auxin promote the best, found in the application of IBA (indole butyric acid) and naphthylacetic (NAA) than indole acetic acid (IAA) and stability, better. Third, to maintain the top edge of plant Stem end is growing plants inhibit the growth of lateral buds, a phenomenon called apical dominance. Control of the cotton top with the growth of DPC or after topping, place a large number of lateral buds. Fourth, inhibiting the formation of abscission zone Cotton and fruit trees falling, fallen fruit and leaves, is a common phenomenon in dicotyledons. Cotton Leiling off, and the supply of nutrients, but also with the level of hormones. When Leiling the base of the handle, well shaft auxin content, auxin concentration is low near shaft, within the inhibition of abscission cellulase, pectinase activity, and thus inhibit the separation cell isolation, Leiling not peel off ; the other hand, when the near shaft auxin content, auxin concentration is far lower shaft, then the pectinase and cellulase activity increased, promoting the separation of abscission layer, resulting in Leiling off. Fifth, promote fruit development and parthenocarpy After fertilization, flowering plants, the IAA content increased in the ovary, thus contributing to the enlargement of the ovary and surrounding tissue, accelerated fruit development. If not fertilized pistil and the ovary can receive timely IAA, also induce the formation of seedless fruits of certain plants. Such as pollination or spray applied before the use of growth hormone on the stigma, without pollination can eventually develop into one of the fruits. Such as pepper, watermelon, tomato, eggplant, holly, squash and figs, etc.
Translated by Google
Wikipedia Daquan
生长素 百科大全
shengzhangsu Auxin auxin That indole acetic acid, is the first found to promote plant growth hormone. English comes from the Greek auxein (growth). CR Darwin, the study of history in 1880 and his son in the final published book, "the ability of plant movement," stated, Canary □ grass grass is cut the top to lose the Coleoptile phototropism response. His explanation is: When the seedlings by light from the side, the top down the impact of transmission, resulting in growth on both sides of the light and back light at different speeds, causing the affected side of the bending of light, which cut out after the top of the light is not present sexual response. 1928 FW Winter tip with the experimental results show there is a promotion of coleoptile growth substances, called growth hormone. It can spread to the agar in a small box will be put back to cut out a small box from the top side of the coleoptile section, can cause the coleoptile to the other side of the bend. And the curvature is roughly contained in the promotion of growth is proportional to the amount of substance. This experiment not only proved the existence of the promotion of growth substances, and the determination to create a well-known auxin "oat trial law." F. L'Aigle in 1933 from human urine and yeast isolated indole acetic acid, it can cause oat coleoptile test law bending. After the proof of that is growth hormone indole acetic acid, being ubiquitous in all plant tissues. Indole acetic acid physical and chemical properties of pure product is white crystal, insoluble in water. Soluble in ethanol, ether and other organic solvents. Easily oxidized in the light turns red, physical activity is also reduced. IAA in plants have showed a free state, but also showed a combination of (bound) state. The latter are mostly ester or peptide complexes. Free state in plants of indole acetic acid content is very low, about 1 kg fresh weight to 100 micrograms, because there are different type of location and organization, strong growth of tissues or organs such as the growing point, the pollen content of more. Biosynthesis and metabolism of tryptophan from the beginning, the way to a five (see Figure indole acetic acid biosynthesis pathway). The figure found in summer squash in ③, ④ present in some cruciferous plants, ⑤ exist in tomato. Auxin degradation, most notably in the light photo-oxidation are prone to be damaged. Tang Yuwei and J. Bonner in 1947 found that some oxidative enzymes in plant tissue can degrade indole acetic acid, known as indole acetic acid oxidase. The most obvious physiological role is the role of growth hormone to promote growth, but on the stem, bud, root growth promoted by the concentration varies. The optimum concentration of the three stem> shoot> root, about 10-5 mole per liter, respectively, 10 ,10-10-8 Moore Moore. Indole acetic acid plants operating direction of the polarity of the performance was mainly the top down. Axillary bud growth inhibition of plant growth in the top edge, and indole acetic acid in the polar transport and distribution are closely related. Auxin also promote callus formation and role of rooting. Because growth hormone in the body can easily be destroyed by metabolism, so when the effects of exogenous short-lived. Similar physiological effects and its analogues can not easily be destroyed, it is widely used in agricultural production (see plant growth regulators). (Cui □)
Translated by Google
Medical Dictionary
Anterior pituitary secretion can promote the growth of a hormone the body. The liver to produce growth hormone auxin through the media to promote indirectly promote the formation of epiphyseal cartilage growth period, and promote the growth of bone and cartilage, so that the body increased. Auxin on intermediary metabolism and energy metabolism are also affected, can promote protein synthesis, enhance sodium, potassium, calcium, phosphorus, sulfur and other important elements of the uptake and utilization, while the consumption of sugar by inhibiting accelerate the decomposition of fat, the energy source by the shift glucose metabolism of fat metabolism. People at an early age, if the growth hormone secretion, can cause growth retardation, physical'm especially small, referred to as "dwarfism"; If excessive secretion of growth hormone can cause whole body overgrowth, skeletal growth is particularly significant, resulting in tall stature abnormalities, referred to as "gigantism." Adult, epiphysis has fused, the growth of long bones is no longer at this time, such as excessive growth hormone secretion, to stimulate the limb bones, facial bone, soft tissue hyperplasia, expressed as hand, foot, nose, jaw, ears, tongue and liver, kidney and other organs show a disproportionate increase, saying "acromegaly." Gigantism and acromegaly, pituitary tumor if it is due to radiation therapy or partial surgical resection, high-dose estrogen can inhibit the role of the pituitary secretion of growth hormone. Dwarfism should be given early on hormone therapy, growth hormone for dwarfism has a significant effect. As the difficulties of auxin sources, so that clinical application of auxin caused by this not widely carried out. Scientists have genetically engineered the current method of trial of human growth hormone gene from the chromosomal DNA isolated chain, cloned into plasmid and transformed with E. coli to the method of production by fermentation of human growth hormone, it is expected to promote the clinical application. In addition, some children with dwarfism, the pituitary growth hormone secreting cells does not reduce, the incidence may be part of neurosecretory cells in the hypothalamus showed degenerative changes, leading to growth hormone releasing hormone deficiency. This current trial in children with synthetic human pancreatic growth hormone releasing factor treatment, has achieved a certain effect.
