ZB3

Plant hormones and plant growth regulators (very complete) Original Title: Plant Hormones and Plant Growth Regulators (Very Complete) In recent years, the market of plant growth regulators is unusually hot, and many plant growth regulator manufacturers have risen rapidly. What is plant growth regulator? Why can such a small bottle have such a magical effect? Are plant growth regulators and plant hormones the same thing? What are the current categories of plant growth regulators? Is it necessary for all crops to use plant growth regulators? How can plant growth regulators be applied safely? What is the market prospect and development trend of plant growth regulators? This print will publish an article continuously in last few period, undertake thorough and detailed introduction and discuss with respect to relevant problem of plant growth regulator. Five common endogenous hormones and their physiological effects 1. Auxin: The code is IAA. Auxin is the first plant hormone discovered, which is a kind of endogenous hormone containing an unsaturated aromatic ring and an acetic acid side chain, including indoleacetic acid (IAA), 4-chloro-IAA, 5-hydroxy-IAA, naphthalene acetic acid and so on. In 1872, Polish horticulturist Sielenski studied the root tip controlling the growth of root elongation zone, and later Darwin and his son studied the phototropism of grass coleoptile. In 1928, Winter first isolated the chemical messenger substance that caused the coleoptile to bend and named it auxin. In 1934, Kaig et al. Identified it as indole acetic acid, so it is customary to use indole acetic acid as a synonym for auxin. Auxin is synthesized in the expanded young leaves and apical meristem and accumulated from top to bottom towards the base by long-distance transport through the phloem. The auxin in plants is formed from tryptophan through a series of intermediate products. The main route is through indole acetaldehyde. Indoleacetaldehyde can be formed by oxidative deamination of tryptophan to indole pyruvate followed by decarboxylation, or by oxidative deamination of tryptophan to tryptamine followed by decarboxylation. The indole acetaldehyde is then re-oxidized to indole acetic acid. Another possible synthetic route is the conversion of tryptophan to indole acetic acid via indole acetonitrile. In plants, IAA can combine with other substances and lose its activity, such as combining with aspartic acid to form indole acetyl aspartic acid, combining with inositol to form indole acetic acid inositol, combining with glucose to form glucoside, and combining with protein to form IAA-protein complex. Conjugated indoleacetic acid, which may be a storage form of auxin in plant tissues, often accounts for 50-90% of indoleacetic acid in plants, and can be hydrolyzed to produce free indoleacetate. Indoleacetic acid oxidase, which is ubiquitous in plant tissues, can oxidize and decompose indoleacetic acid. Growth hormone has many physiological effects, which are related to its concentration. The physiological effects of auxin are manifested at two levels. At the cellular level, auxin can stimulate the division of cambium cells, stimulate the elongation of branch cells, inhibit the growth of root cells, promote the differentiation of xylem and phloem cells, promote the rooting of cuttings, and regulate the morphogenesis of callus. At the organ and whole-plant level, auxin acts from seedling to fruit maturity. Auxin controls reversible red light inhibition of seedling mesocotyl elongation; gravitropism of shoots occurs when indoleacetic acid is transferred to the lower side of the shoot; phototropism of shoots occurs when indoleacetic acid is transferred to the backlit side of the shoot; indoleacetic acids cause apical dominance; leaf senescence is delayed; auxin applied to leaves inhibits abscission, while auxin applied to the proximal end of the abscission layer promotes abscission; Auxin promotes flowering, induces parthenocarpic fruit development, and delays fruit ripening. The specific physiological effects of auxin are as follows: First, promote growth. Auxin can promote growth at low concentrations, but inhibit growth at high concentrations, even cause plant death. This inhibition is related to whether it can induce the formation of ethylene. In addition, the sensitivity of different organs to auxin is different. Second, promoting the formation of adventitious roots of cuttings. The method of using auxins to promote the formation of adventitious roots of cuttings has been widely used in the asexual propagation of seedlings. Expand the full text Third, the regulation and transportation of nutrients. Auxin has a strong effect of attracting and transporting nutrients. By using this characteristic, auxin treatment can promote the expansion of ovary and its surrounding tissues and obtain seedless fruits. Fourth, other effects of auxin. For example, it can promote pineapple flowering, cause apical dominance (that is, the inhibition of lateral bud growth by terminal buds), induce female flower differentiation (but not as effective as ethylene), promote the differentiation of cambium cells to xylem cells, promote the transport of photosynthates, the enlargement of leaves and the opening of stomata. In addition, auxin can also inhibit flower abscission, leaf aging and root formation. 2. Gibberellin: code name is GA. Gibberellin is a kind of plant hormone that mainly promotes internode growth. It is named after the discovery that the material used in its action and separation and purification comes from gibberellin. Fusarium graminearum is the pathogen of rice bakanae disease, and the high growth rate of infected plants is much higher than that of disease-free plants. In 1926, Eiichi Kurosawa of Japan used the cell-free filtrate of Gibberella culture medium to treat disease-free rice, resulting in the same overgrowth phenomenon as infected plants, suggesting that there are substances in Gibberella that promote rice growth. The bioactive substance was isolated from the filtrate of the culture medium of Gibberella zeae in 1938 by Sadajiro Hata and Yukisuke Sumigi of Japan, and its chemical structure was identified. It is named gibberellic acid. 1956 C. A． West and B. O． Fini respectively proved that some substances similar to gibberellic acid are ubiquitous in higher plants. So far, more than 120 kinds of gibberellins have been found, which are generally divided into free form and bound form, collectively known as gibberellins. It is one of the most diverse plant hormones. Gibberellins contain (–) -gibberellinane skeleton, which is a diterpene compound with complex chemical structure. The nearest precursor of gibberellins in higher plants is generally considered to be kaurene. The differences between the various gibberellins are in the number and position of the double bonds, hydroxyl groups. Free gibberellins are mono-, di-, or tricarboxylic acids with 19 C or 20 C. Conjugated gibberellins are mostly glucosides or glucosyl esters, which are easily soluble in water. Gibberellin can be extracted with methanol. The different gibberellins can be separated by various chromatographic techniques. The biological activity of purified gibberellin can be identified by treating dwarf plants, such as dwarf maize, with diluted gibberellin and observing its effect on promoting height growth. Different gibberellins have different biological activities, and gibberellic acid (GA3) has the highest activity. Compounds with high activity must have a gibberellin ring system (ring ABCD) with a carboxyl group at C-7 and a lactone ring at the A-ring. The gibberellin content varies from part to part of the plant, being most abundant in the seeds, especially at maturity. The application of gibberellin in agricultural production has a good effect in some aspects. For example, the yield of seedless grapes is improved and the dormancy of potatoes is broken; GA3 is used to promote the germination of barley seeds for preparing maltose during brewing beer; gibberellin treatment can promote the heading of late rice when the heading is slow due to rain and low temperature; or the flowering period is adjusted in hybrid rice seed production so that the flowering periods of parents meet. As for the mechanism of action of gibberellin, its induction of starch hydrolysis in degerminated barley seeds has been studied in depth. GA3 was found to significantly promote the de novo synthesis of α-amylase in the aleurone layer of sterilized degerminated barley seeds treated with GA3, thereby causing the hydrolysis of starch. When intact barley seeds germinate, the embryo contains gibberellin, which is secreted into the aleurone layer. In addition, GA3 also stimulated aleurone layer cells to synthesize protease and promote the secretion of ribonuclease and glucanase. The physiological effects of gibberellin are as follows: First, promote the elongation and growth of stems. This is mainly to promote the elongation of cells. Gibberellin treatment can significantly promote the elongation of plant stems, especially for dwarf mutant varieties, and also promote the elongation of internodes. There is no inhibition of super-optimal concentration, and even if the concentration of gibberellin is very high, it can still show the greatest promotion effect, which is significantly different from the situation that auxin promotes plant growth with optimal concentration. There are great differences in the response of different plant varieties to gibberellin. It can be used on vegetables (celery, lettuce, leek), pasture, tea and ramie to obtain high yield. Second, induce flowering. Flower bud differentiation in some higher plants is influenced by day length and temperature. If gibberellin is applied to these non-vernalized plants, flowering can be induced without low temperature process, and the effect is obvious. In addition, gibberellin can also induce flowering of some long-day plants instead of long-day, but gibberellin has no effect on flower bud differentiation of short-day plants. For the plants whose flower buds have been differentiated, GA has a significant promoting effect on their flower opening. For example, gibberellin can promote the flowering of Stevia rebaudiana, sago Cycas, Cupressaceae and Linariaceae. Third, break dormancy. Gibberellin can replace light and low temperature to break dormancy for seeds that need light and low temperature to germinate, such as lettuce, tobacco, perilla, plum and apple. And fourthly, promote that differentiation of male flowers. For dioecious plants, the proportion of male flowers increased after treatment with gibberellin; for dioecious plants, female plants treated with gibberellin also produced male flowers. The effect of gibberellin in this respect is opposite to that of auxin and ethylene. Fifth, other physiological effects. Gibberellin can also enhance the mobilization effect of auxin on nutrients, promote fruit setting and parthenocarpy of some plants, and delay leaf senescence. In addition, gibberellin can also promote cell division and differentiation, and gibberellin can inhibit the formation of adventitious roots, which is contrary to auxin. Cytokinin: its code name is CTK. Cytokinin is a kind of plant hormone with adenine ring structure. Their common feature is a specific substitution at position 6 of the adenine ring. Their physiological functions are prominent in promoting cell division and inducing bud formation. In 1948, Skog of the United States and Cui Wei of China found that adenine could induce tobacco pith tissue to differentiate into buds in tobacco tissue culture. In 1955, Miller et al. Separated and purified the substance promoting cell division from the degradation product of yeast deoxyribonucleic acid and the deoxyribonucleic acid of herring sperm, and named it kinetin (KT). Its chemical structure is 6-furfurylmethyladenine, also known as furfuryladenine. In 1963, Latham isolated the first natural cytokinin in higher plants and named it zeatin (Z) from tender corn seeds 11 ~ 16 days after fertilization. At present, more than 20 adenine derivatives have been obtained from higher plants. Uch as dihydrozeatin, zeatin riboside (ZR), and prenyladenine. In recent years, many similar substances have been synthesized, such as 6-benzyladenine (BA), tetrahydropyranylbenzyladenine (PBA) and so on. They are commonly known as cytokinins (CTK). Cytokinins are most actively synthesized in the root meristem (root tip) and are transported from root to stem over long distances by the xylem. Cytokinins are also formed in young leaves, buds, young fruits, and developing seeds. Zeatin was first obtained from immature corn seeds. Cytokinins are produced by the cleavage of transfer ribonucleic acid (tRNA) and are also synthesized from mevalonate and adenine as precursors. Cytokinins have a variety of physiological effects. Its physiological effects are as follows: First, to promote cell division, the main physiological function of cytokinin is to promote cell division. Auxin, gibberellin and cytokinin all have the effect of promoting cell division, but their effects are different. Auxin only promotes the division of nucleus, but has nothing to do with the division of cytoplasm. Cytokinin, on the other hand, mainly acts on the division of cytoplasm. Second, promote the differentiation of buds. Promoting the differentiation of buds is one of the important physiological effects of cytokinin. Some isolated leaves can produce buds at the base of the main vein and the leaf margin after cytokinin treatment. Third, promote cell expansion. Cytokinin can promote the enlargement of cotyledons or leaf discs of some dicotyledonous plants such as kidney bean and radish, which is mainly due to the promotion of transverse thickening of cells. Fourth, promote the development of lateral buds and eliminate apical dominance. The cells can relieve the apical dominance caused by auxin and promote the growth and development of lateral buds. For example, if a solution of cytokinin is added to the leaf axils of pea seedlings, the axillary buds can grow and develop. Fifth, delay the senescence of leaves. If cytokinin is applied locally to the detached leaves, the rest of the leaves will remain bright green when they turn yellow and senesce. Because cytokinin has the functions of keeping green and delaying senility, it can be used to treat fruits and flowers to keep fresh, keep green and prevent fruit drop. For example, the treatment of young citrus fruits with cytokinin can significantly prevent fruit drop, and the fruit stalk is thicker, the fruit is dark green, and the fruit size is significantly larger than that of the control. Sixth, break the seed dormancy. Seeds that need light, such as lettuce and tobacco, can not germinate in the dark. Cytokinin can replace light to break the dormancy of these seeds and promote their germination. 4. Abscisic acid: ABA. In the fifties of this century, people have paid attention to the effects of growth inhibitors on abscission, dormancy and germination, and considered that phenolic compounds are the main growth inhibitors in plants. In the early 1960s, a breakthrough was made in the study of growth inhibitors. In 1963, Addicott and others in the United States discovered a compound with strong activity to cause abscission when they studied the abscission of cotton buds and bolls, which was named abscisin II. In the same year, Wareing et al. Studied the compounds causing dormancy of birch and maple trees, and isolated an active substance capable of inducing dormancy from the leaves of these trees, named dormin. In 1964, it was proved that abscisin II and narcoleptin were the same compound, and in 1965, its chemical structural formula was determined. In 1967, this compound was named abscisic acid (ABA) at the Sixth International Conference on Plant Growth Substances. Abscisic acid is formed in many parts, such as senescent leaf tissues, mature fruits, seeds, stems and roots. Water deficit can promote the formation of abscisic acid. ABA is rapidly redistributed in plants and is present in the phloem and xylem sap flow. The precursor for the synthesis of abscisic acid is mevalonic acid, which has two routes to go after the formation of farnesyl pyrophosphate. One is the C15 direct pathway, which is common in fungi. One is the indirect pathway of C40 in higher plants. The latter first forms carotenoid (violaxanthin), which is cracked into C15 xanthine by light or biological oxidation, and then converted into abscisic acid. The physiological functions of abscisic acid are as follows: First, promote dormancy. When ABA is used externally, it can stop the vigorous growth of branches and enter dormancy, which is why it was originally called “dormancy”. Under the condition of short days in autumn, the amount of GA synthesized by mevalonic acid in leaves decreased, while the amount of ABA synthesized increased, which made the buds enter dormancy for overwintering. Seed dormancy is related to the presence of abscisic acid in the seed. For example, there is abscisic acid in the testa of dormant seeds of peach and rose, so the seeds can germinate normally only after the level of abscitic acid is reduced by stratification treatment. Second, promote stomatal closure. ABA can cause stomatal closure and reduce transpiration, which is one of the most important physiological effects of ABA. Cornish (K. Cornish, 1986) found that the ABA content in guard cells of leaves under water stress was 18 times higher than that under normal water conditions. The reason of stomatal closure induced by ABA is that ABA makes K + exosmosis in guard cells, which makes the water potential of guard cells higher than that of surrounding cells and lose water. ABA can also promote the water absorption and exudation rate of roots, and increase the amount of water supplied to the aboveground part, so ABA is a hormone regulating transpiration in plants, and can also be used as an antitranspirant. Third, growth inhibition. ABA can inhibit the growth of whole plants or isolated organs, and also inhibit the germination of seeds. The inhibitory effect of ABA is a thousand times higher than that of phenol, another natural inhibitor in plants. Phenols exert their inhibitory effect through toxicity, which is irreversible, while the inhibitory effect of ABA is reversible. Once ABA is removed, the growth of branches or the germination of seeds will begin immediately. Fourth, promote shedding. ABA was discovered when studying the shedding of young cotton bolls. ABA promotes the formation of abscission layer. When ABA was applied to the petiole cut of cotton explants with leaves removed, the petiole began to fall off after a few days. This effect was so obvious that it has been used in the bioassay of abscisic acid. Fifth, increase stress resistance. Generally speaking, stress such as drought, cold, high temperature, salt and waterlogging can rapidly increase ABA in plants, and at the same time enhance stress resistance. For example, ABA can significantly reduce the damage of high temperature to the ultrastructure of chloroplasts, increase the thermal stability of chloroplasts, and induce the re-synthesis of some enzymes to increase the cold resistance, waterlogging resistance and salt resistance of plants. Therefore, ABA is called stress hormone or stress hormone. 5. Ethylene: ACC. Ethylene is a gaseous hormone. In the mid-19th century, it was found that the leakage of lighting gas could affect the growth and development of plants. In 1901, Niliubov, a Russian scholar, confirmed the role of ethylene in lighting gas and discovered the “triple reaction” of plants to ethylene. The extensive effects of ethylene on plants and its use as a ripening agent for fruits were identified in the 1920s and 1930s. In 1934, the concept of ethylene as a mature hormone was put forward by Clark et al. Of the Bois Thomson Institute in the United States. In the late 1950s, Berg and others introduced gas chromatography into ethylene research to accurately determine and track the trace amount of ethylene in tissues and its changes. Ethylene was recognized as an endogenous plant hormone in the late 1960s. In 1964, Lieberman proposed that ethylene came from methionine. In 1979, Adams and Young found that 1-aminocyclopropanecarboxylic acid (ACC) was the precursor of ethylene synthesis, and determined that the pathway of ethylene synthesis was methionine adenosylmethionine (SAM) ACC ethylene. ACC synthase, which catalyzes the formation of ACC from SAM, is the main rate-limiting factor in ethylene synthesis. Aminoethoxyethyleneglycine (G), aminooxyacetic acid (AOA) and other substances can effectively inhibit this reaction. Almost all higher plant tissues produce trace amounts of ethylene. Drought, waterlogging, extreme temperature, chemical damage, and mechanical damage can stimulate the increase of ethylene in plants, known as “stress ethylene”, which can accelerate organ aging and shedding. Germinating seeds, fruits and other organs have high ethylene content during maturity, senescence and abscission. High concentration of auxin promotes ethylene production. Ethylene inhibits the synthesis and transport of auxin. The physiological effects of ethylene are as follows: First, change the growth habit. The typical effects of ethylene on plant growth are: inhibition of stem elongation, promotion of lateral thickening of stems or roots, and lateral growth of stems (even if the stems lose negative gravity). This is the “triple response” peculiar to ethylene. Ethylene promotes lateral growth of stems because it causes upward growth. The so-called upward growth refers to the phenomenon that the upper part of the organ grows faster than the lower part. Ethylene has an upward effect on both the stem and the petiole, causing the stem to grow horizontally and the leaves to droop. Second, promote maturity. Ripening is the most important and significant effect of ethylene, so ethylene is also called ripening hormone. Ethylene has a significant effect on fruit ripening, cotton boll cracking, rice filling and ripening. In real life, we know that once there is a rotten apple in the box, if it is not removed immediately, it will soon make the whole box of apples rotten. This is because the ethylene produced by rotten apples is more than that produced by normal apples, which triggers the nearby apples to produce a large amount of ethylene, so that the concentration of ethylene in the box increases sharply in a relatively short period of time, induces respiratory climacteric, and accelerates the maturity of apples and the consumption of storage substances. Another example is persimmon, even if it is ripe on the tree, it is still very astringent and can not be eaten, only after the ripening process can it be eaten. Because ethylene is a gas, it is easy to diffuse, so the ripening process of scattered persimmons is very slow, and it is still difficult to eat after ten days and a half months. If the container is sealed (such as plastic bags), the ethylene produced by the fruit will not diffuse, coupled with its own catalytic effect, the ripening process is accelerated, and it can be eaten after 5 days. Third, promote shedding. Ethylene is the main hormone controlling leaf abscission. This is because ethylene promotes the synthesis of cell wall degrading enzymes cellulase and controls the release of cellulase from the protoplast into the cell wall, thereby promoting cell senescence and decomposition of the cell wall, causing swelling of cells near the stem side of the abscission zone, thereby forcing mechanical detachment of leaves, flowers, or fruits. Fourth, promote flowering and female flower differentiation. Ethylene can promote the flowering of pineapple and some other plants, change the sex of flowers, promote the differentiation of female flowers of cucumber, and reduce the node position of female flowers in monoecious plants. The effect of ethylene in this respect is similar to that of IAA, but in contrast to GA, it is now known that the increase in female flower differentiation by IAA is due to the induction of ethylene production by IAA. Fifth, other effects of ethylene. Ethylene can also induce the formation of adventitious roots of cuttings, promote the growth and differentiation of roots, break the dormancy of seeds and buds, and induce the secretion of secondary substances (such as latex of rubber trees). In addition to the above five kinds of plant hormones, plants also contain a variety of trace organic compounds synthesized by themselves, which regulate the growth and development of plants at very low concentrations. These substances mainly fall into the following categories. 1. Brassinosteroids. (BRs) BRs are widely distributed in the plant kingdom, and the amount is very small. Its main functions are: promoting cell elongation and division; improving photosynthesis; and enhancing the stress resistance of plants. 2. Polyamines. It is widely found in microorganisms, animals and plants. Polyamines have the function of stabilizing nucleic acids and ribosomes, and can promote the biosynthesis of nucleic acids and proteins. 3. Jasmonic acids. It is found throughout the plant kingdom (including algae) and is a growth inhibitor. It can inhibit the growth of rice, wheat and lettuce seedlings, inhibit the germination of seeds and pollen, and delay the growth of roots. In addition, salicylic acid, zearalenone and other growth substances in plants also play a regulatory role. Because of the overlap between its effects and the physiological effects of the hormones described above, the actual production of related regulator products is less involved and will not be repeated here. Random talk on plant growth regulator With the study of plant endogenous hormones, people are constantly using synthetic methods to make some analogues with plant hormone activity for agricultural production, which is plant growth regulators. Compared with endogenous hormones, the physiological effects of plant growth regulators are more targeted and purposeful. It is divided into the following categories. Plant growth regulators can be divided into five categories according to their roles in agricultural production, namely, plant growth promoters, plant growth inhibitors, plant growth retardants, fresh-keeping agents and drought-resistant agents. Types and main functions of plant growth regulators. 1. Plant growth promoter Compounds that promote plant cell division, differentiation, and prolonged growth are growth promoters that promote the growth of vegetative organs and the development of reproductive organs in plants. This is one of the most widely used plant growth regulators. Gibberellin (GA) Other names 920, GA Most of the products used in agricultural production are 85% gibberellin crystal powder, 4% gibberellin emulsifiable concentrate, 40% water-soluble tablets and 40% water-soluble powder. Gibberellin is a broad-spectrum plant growth regulator, which has been introduced in detail in “Talking about Plant Growth Regulators (One)”. Endogenous gibberellin is ubiquitous in plants, which is one of the important hormones to promote plant growth and development. It is also an antagonist of inhibitors such as paclobutrazol and chlormequat. Gibberellin can promote cell elongation, stem elongation, leaf enlargement, parthenocarpy and fruit growth, break seed dormancy, change the ratio of female and male flowers, affect flowering time, and reduce flower and fruit abscission. Exogenous gibberellin has the same physiological effects as endogenous gibberellin when it enters plants. Gibberellin mainly enters the plant body through leaves, twigs, flowers, seeds or fruits, and then is transmitted to the active growth parts to play a role. Gibberellin is widely used in agriculture, forestry and horticulture. Naphthylacetic acid (NAA) Other names Fengyousu, Maijian The common preparation is 80% raw powder, and there are 99% refined powder, 2% sodium salt aqua, 2% potassium salt aqua and 4.2% naphthalene acetic acid aqua in the market. Naphthylacetic acid (NAA) is an auxin-like substance and a broad-spectrum plant growth regulator. Its main effects on plants are to promote cell division and expansion, induce the formation of adventitious roots, increase fruit setting, prevent fruit drop, change the ratio of male and female flowers, promote plant metabolism and photosynthesis, accelerate growth and development, and enhance resistance. Naphthylacetic acid enters the plant body from the tender epidermis of leaves and branches and seeds, and is transported to the action site with the nutrient flow. At present, there are three enterprises that produce the raw powder of naphthylacetic acid and obtain the pesticide registration certificate number from the Pesticide Identification Institute of the Ministry of Agriculture, namely, the raw sodium naphthylacetic acid of Zhengzhou Zhengshi Chemical; the raw naphthyl acetic acid of Sichuan Guoguang; and the raw naphthyl acetic acid powder of Henan Anyang Chemical Experimental Factory. Auxin (IAA) Other names indoleacetic acid, iso-auxin, auxin 3-indoleacetic acid, etc. Most of the products used in agricultural production are powder and wettable powder, which are synthetic products with auxiliary materials. The action characteristics of auxin have been introduced in detail in Random Talk on Plant Growth Regulators (I). It has a wide range of physiological effects. It affects cell division, cell elongation and cell differentiation, as well as the growth, maturity and aging of vegetative organs. It can be absorbed by stems, leaves and roots, and can be promoted or inhibited due to different application concentrations. Because indole acetic acid is easy to be decomposed by light, is easy to be decomposed by indole acetic acid oxidase in plants, is expensive and the like, the application in production is limited, and the indole ethanoic acid is mainly used for inducing callus and root formation in tissue culture. At present, there are only a few enterprises that directly produce auxin, such as Tianjin Tiantai Fine Chemical Quality Company and Dongfeng Reagent Factory of Biochemical Research Institute of Chinese Academy of Sciences in Shanghai. 2,4-D Other names: Zuo Guo Ling, Fang Luo Su The common formulations are 80% wettable powder, 72% butyl ester emulsifiable concentrate, 55% and 50% amine salt aqua. 2, 4-D has many different effects on plants with different concentrations and dosages: it is one of the components of the medium for plant tissue culture at lower concentrations (0.5-1.0 mg/L), and it can prevent flower and fruit drop, effectively stimulate growth, induce seedless fruit and keep fruit fresh at medium concentrations (1-25 mg/L); At a higher concentration (1000 mg/L), it can be used as a herbicide to kill a variety of broadleaf weeds. Therefore, it is important to pay attention to the amount used when applying to crops. Higher concentrations inhibit growth, and higher concentrations can cause abnormal development and death of plants. As a post-emergence herbicide, monocotyledonous gramineous plants have a certain tolerance to it, and dicotyledonous broad-leaved plants are very sensitive to it. By using this selectivity, it can be used to control broad-leaved weeds in rice and wheat gramineous crops. The 50% 2,4-D amine salt at the dosage of 200ml/mu has excellent control effect on broadleaf weeds such as Alternanthera philoxeroides, Humulus scandens, Birdberry, Acalypha australis, Stellaria media, Oxalis corniculata, Parthenocissus tricuspidata, Cephalanoplos segetum and Carpesium japonicum in citrus orchards after 20 days, and the weeding effect is 92.5% -100%. It also has good control effect on Erigeron annuus, Amaranthus hypochondriacus, Xanthium sibiricum and Polygonum fortunei, with a control effect of about 80%. The low control effect may be related to the high age of the four weeds mentioned above, and most of them have blossomed and fruited. The 50% 2,4-D amine salt was safe to citrus trees at the tested dose. Kinetin (KT) Other names KT, Kinetin The chemical name of kinetin is 6-furfurylaminopurine, and its molecular formula is C10H9N5O. It is generally formed by condensation of 6-chloropurine and furfuryl amine. Insoluble in water, soluble in strong acids, alkalis and glacial acetic acid. It was the first substance found to have cytokinin action and was first proposed from the degradation products of deoxyribonucleic acid. In the case of tissue culture, the low concentration of kinetin can promote the differentiation of roots, while the high concentration can promote the differentiation of branches, leaves and buds. The middle concentration of kinetin can significantly promote cytokinesis and form wound tissue blocks. Kinetin can obviously inhibit senescence, especially for the separated mature leaves. It can inhibit the decrease of chlorophyll, protein, nucleic acid and other contents, and also delay the destruction of cell structure. Delays the degradation of protein and chlorophyll, delays the senescence of plants, and can be used for the preservation of fruits and vegetables. At present, Shanghai Xibao Biotechnology Co., Ltd., Shanghai Jiafeng Horticultural Products Co., Ltd. and Xiamen Xinglongda Chemical Reagent Co., Ltd. provide kinetin related products. Swelling agent Forchlorfenuron, whose English generic name is FORCHLORFENURON and English abbreviation is CPPU (N-2-chloro-4-pyridylphenyl-N '-phenylurea), is a phenylurea substance, mainly a substance that stimulates cytokinin, which was first developed by Sandoz Company of the United States, which has always advocated “high-tech” technology. CPPU was first developed by Kyowa Fermentation Industry Co., Ltd. in 1985, but it was not used in production in Japan because CPPU promoted cell division and enlargement, at the same time, it appeared malformed fruit and shortened storage period of fruit. Researchers in our country are scrambling to introduce it. The Fruit Tree Institute of the Chinese Academy of Agricultural Sciences introduced it from Japan in the late 1980s. In 1992, the Ministry of Agriculture approved the product. Forchlorfenuron is a highly active compound with cytokinin activity, which can promote cell division and expansion. When applied to melon and fruit plants, it can promote flower bud differentiation, protect flowers and fruits, improve fruit setting rate and promote fruit expansion. But the side effects on humans are also gradually being discovered. Other names for ethephon are Yishiling, Ethephon, Zaotianhong. The chemical name of Ethrel is 2-chloroethyl phosphonic acid, and its molecular formula is C2H5O2Cl. The common preparation is 40% Ethrel aqua. Ethephon was first synthesized in 1967 using ethylene oxide and phosphorus trichloride as raw materials. Pure ethephon is a needle-like white crystal with a melting point of 75 ℃. It is easy to absorb water and deliquesce, and is soluble in water and organic solvents. The commercial product is generally a brown viscous liquid with a concentration of about 40% and a pH of about 1. Ethylene is easily released from ethephon at pH > 4. The release rate of ethephon increases with the increase of temperature and pH, and ethephon is slightly toxic to human and animals. Ethephon is used on plants and is rapidly absorbed by plant tissues. Because the pH of plant cell sap is > 4.1, ethephon can gradually decompose and release ethylene at the treatment site, and can also move in the body and release ethylene at other sites. Ethephon itself has no physiological activity, and the released ethylene is a plant hormone with a variety of physiological functions. The clear physiological effects include: promoting the physiological maturity of fruits (at present, in order to advance the market time of bananas, oranges, peaches, tomatoes and other fruits, ethephon treatment is widely used), promoting leaf senescence and abscission, and promoting seed germination and plant flowering. Promote the growth of roots and seedlings. If applied improperly, it will cause the loss of leaves and fruits, dwarf plants, change the ratio of male and female, and induce male sterility in some crops. At present, there are two enterprises that produce ethephon technical and have obtained the pesticide registration number in the pesticide identification Institute of the Ministry of Agriculture, namely, Jiangsu Anbang Electrochemical Co., Ltd. and Jiangsu Changshu Pesticide Factory. Other names for DA-6 are Dafengli, diethyl aminoethyl hexanoate, synergistic amine. The active ingredient in DA-6 is diethylaminoethyl carboxylate, an oily liquid. The code name is :DA-6。 It is often made into organic salts, such as DA-6 citrate. DA-6C is a white or powdery solid. DA-6 humate DA-6H is a brown or tan fine-grained solid. DA-6 can increase the content of chlorophyll, protein, nucleic acid and photosynthetic rate in plants, improve the activity of peroxidase and nitrate reductase, promote the metabolism of carbon and nitrogen in plants, enhance the absorption of water and fertilizer and the accumulation of dry matter, regulate the water balance in plants, enhance the disease resistance, drought resistance and cold resistance of crops and fruit trees, and delay the senescence of plants. Promote the early maturity of crops, increase the yield, and improve the quality of crops, so as to increase the yield and improve the quality. DA-6 is a newly discovered efficient plant growth substance, which has significant effects on yield increase, stress resistance, disease resistance, quality improvement and early maturity of various crops, and has high biological activity. It can be compounded with various elements, and can also be compounded with fungicides to enhance the disease resistance of plants and improve the bactericidal effect. DA-6 has been widely used in agriculture because of its unique multifunctional effect. DA-6 is a white or flaky powdery crystal with a content of more than 98%. It can be used in combination with various pesticides and fertilizers and is stable in weak acid and neutral media. DA-6 alone works best at 10-15 PPM, that is, 70-100 kg of water per gram of DA-6. When DA-6 is compounded with fertilizers, fungicides and herbicides, the best effect is at 5 PPM, and the dosage per ton is generally one hundredth of the dilution multiple of the product. Other names of compound sodium nitrophenolate are synergistic sodium, love more harvest, more harvest, quick harvest, Tom Youguo, Wanguobao and Hualeibao. Sodium 5-nitroguaiacolate, sodium ortho-nitrophenolate and sodium para-nitrophenolate are the chemical components of compound sodium nitrophenolate. Its physical and chemical properties are purplish red flaky crystals, dark red needle-like crystals and mixed crystals, which are soluble in water and organic solvents such as ethanol, methanol and acetone. Stable at room temperature. Have a phenolic aroma. It has been made into 2%, 1.8%, 0.9%, 1.4%, 0.7% and 2.85% aqueous formulations and 1.4% compound nitrophenol soluble powder by many manufacturers. Compound sodium nitrophenolate is a powerful cell activator, which can quickly penetrate into the plant body after contacting with the plant, promote the protoplasm flow of the cell and improve the cell vitality. It can speed up rooting, break dormancy, promote growth and development, prevent flower and fruit drop, improve product quality, increase yield, and improve the resistance of crops to diseases, insects, drought, waterlogging, cold, salt and alkali, and lodging. It is widely suitable for grain crops, economic crops, vegetables, melons and fruits, fruit trees, oil crops and flowers. It can be used at any time between sowing and harvesting of plants, and can be used for seed impregnation, seedbed irrigation, foliar spraying and bud spreading. Because of its high efficiency, low toxicity, no residue, wide range of crops, no side effects, wide range of concentrations and other advantages, it has been widely used in many countries and regions in the world. Compound sodium nitrophenolate is also used in animal husbandry and fishery to improve the yield and quality of meat, eggs, hair and skin, as well as to enhance the immunity of animals and prevent various diseases. Brassinolide Other names brassinolide, brassinosterol, Nongleli, Tianfengsu, Yifengsu, BR-120, etc. Brassinolide, whose chemical name is 2α, 3α, 22s, 23s-tetrahydroxy-24R-ethyl-β-homo-7-oxa-5α-cholest-6-one, decarboxylation after extraction ,wiped film evaporator, is an artificial compound of biomimetic plant endogenous hormone-brassinolide. That common preparation include 0. 01% brassin lactone emulsifiable concentrate, 0. 2% brassin lactone soluble powder, 0.1% of brassinolide soluble powder, 0.15% of emulsifiable concentrate and 0.04% of aqua. The brassinolide has the main functions of promoting cell division, elongation and growth, being beneficial to pollen fertilization, improving the fruit setting rate, improving the chlorophyll content, increasing the photosynthesis and enhancing the stress resistance of plants. In addition, when the compound is mixed and applied with a plurality of common fungicides, chemical fertilizers and plant growth regulators, the compound has remarkable synergistic effect and addition effect, can improve the fertilizer efficiency of the chemical fertilizers and the efficacy of the fungicides and reduce the phytotoxicity of pesticides in most cases; The mixed preparations with various plant growth regulators or foliar fertilizers have extremely broad development prospects and market potential in improving crop quality, stress resistance and disaster reduction, and have attracted the attention of many pesticide and fertilizer manufacturers and scientific research institutions at home and abroad. 2. Plant growth inhibitor Plant growth inhibitors mainly inhibit the synthesis of auxin, which can inhibit the biosynthesis of nucleic acid and protein in stem apical meristem cells, resulting in slow cell division and short plants. At the same time, growth inhibitors also inhibit the elongation and differentiation of apical meristem cells, affecting the growth and differentiation of lateral branches, leaves and reproductive organs at that time. Therefore, after destroying apical dominance, the number of lateral branches is increased. The leaves become smaller, and the development of reproductive organs is also affected. Two 3. Plant growth retardants Plant growth retardants mainly inhibit the biosynthesis of gibberellin, inhibit the growth of plant subapical meristem, slow down cell elongation, shorten internodes without reducing the number of cells and internodes, and shorten plants. But did not affect the formation of leaves and flowers. Therefore, it does not affect the development of leaves and the number of leaves, and generally does not affect the development of flowers. The effect was reversed when GA was applied. Other names of chlormequat: CCC (chlorocholine chloride), chlorocholine chloride, Daomaili, Sanxi, Xixixi. The chemical name of chlormequat is 2-chloroethyltrimethylammonium chloride. White powdery solid with fishy odor, strong hygroscopicity, easy to dissolve in water. The commonly used dosage forms are 5%, 40%, 50%, 64% aqua and raw powder. Chlormequat is a plant growth regulator with low toxicity. The medicament mainly inhibits the cell elongation of the plant, but does not inhibit the cell division, does not affect the formation of organs, can make the plant short and strong, thicken the stem, deepen the leaf color, enter the plant body to inhibit the biosynthesis of gibberellin, and is an antagonist of gibberellin. It hinders the biosynthesis of gibberellin. Its function is to inhibit the cell division of the subapical meristem or primary meristem at the stem apex of the plant, thus shortening the internodes, making the plant shorter, and making the leaves dark green. It is often used to control the growth of wheat and cotton to prevent lodging and excessive growth. In addition, it can also be used for cultivating strong seedlings of grape, sorghum, tomato, potato, corn, flowers and vegetables to prevent lodging and increase yield. When chlormequat is used as a dwarfing agent, the soil water and fertilizer conditions should be good, and it should not be used when the fertility is poor and the crop growth is not vigorous. After the use of chlormequat, the leaves of crops are dark green, which can not be judged as the performance of sufficient fertilizer and water, but should strengthen the management of fertilizer and water to prevent fertilizer loss. The sweetness of grape fruit will decrease after spraying chlormequat, but it will not decrease the sugar content if it is mixed with boron. Do not smoke, drink, or eat while dispensing and administering. Wash hands and face in time after work. Dizziness, fatigue, numbness of lips and limbs, miosis, salivation, nausea, vomiting, convulsions and coma in severe cases can be treated with atropine as appropriate. The chemical name of paclobutrazol is (2RS, 3RS) -1- (4-chlorophenyl) -4,4-dimethyl-2- (1H-1,2,4-triazol-1-yl) pentan-3-ol, which is a white solid, insoluble in water and soluble in organic solvents such as methanol. The common dosage forms are 95% paclobutrazol technical, 10% paclobutrazol wettable powder and 15% paclobotrazol wettable powder. Paclobutrazol has the effects of delaying plant growth, inhibiting stem elongation, shortening internodes, promoting plant tillering, increasing plant stress resistance, increasing yield and the like. It is suitable for rice, wheat, peanut, fruit tree, tobacco, rape, soybean, flower, lawn and other crops (plants). Especially, it has the functions of delaying the top growth of rice seedlings, increasing roots and tillers, cultivating strong seedlings, improving the quality of seedlings, advancing maturity, inhibiting weeds and increasing yield. When it is used in seedling bed, it can improve the photosynthetic intensity of seedling leaves, promote root respiration, and inhibit the excessive growth of seedlings. Paclobutrazol remains in the soil for a long time, so it must be ploughed after harvest to prevent the inhibition of subsequent crops. In general, the use of paclobutrazol is not easy to produce phytotoxicity, if the dosage is too high, when the seedling inhibition is excessive, nitrogen or gibberellin can be applied to rescue. Different varieties of rice have different growth potential because of their different levels of endogenous gibberellin and indoleacetic acid. The varieties with stronger growth potential need to use more drugs, while the varieties with weaker growth potential need to use less. In addition, when the temperature is high, more pesticides should be applied, otherwise less pesticides should be applied. Bijiu Other names: B9, B995, Hydrazide, SADH, Alar, etc. The chemical name for daminozide is dimethylamine succinamic acid, or N, N dimethyl succinyl hydrazide. Soluble in water, soluble in acetone, ethanol, xylene and other organic solvents. The common dosage forms are 85%, 90% water soluble powder and 5% liquid. After its successful development in 1962, it was used in the production of apples, grapes, peaches, plums and other fruit trees all over the world. Bijiu is a plant growth retardant, which can inhibit the excessive growth of plants, dwarf and strengthen plants, prevent flower drop and promote fruiting. It is used to adjust the height of the trunk and the shape of ornamental plants. When the agent enters the plant, it can inhibit the biosynthesis of endogenous gibberellin, and also inhibit the synthesis of endogenous auxin. Its main function is to inhibit the excessive growth of new branches, shorten the length of internodes, increase the thickness of leaves and chlorophyll content, induce the formation of adventitious roots, stimulate the growth of roots, improve cold resistance and promote fruit setting. In the past, it was usually used for fruit trees, potatoes, sweet potatoes, peanuts, tomatoes, strawberries, chrysanthemums, ginseng and so on, instead of artificial pruning, and at the same time it is conducive to flower bud differentiation. Increase the number of flowers and fruit setting rate. It is worth noting that since 1987, some experimental results have shown that Bijiu is toxic to humans and can cause cancer. After comparative studies, discussions and disputes by many scholars from various aspects, it has been determined that Bijiu is an internationally recognized carcinogen and has been banned from fruit trees and peanuts since 1990. However, due to the lax management and the low quality of farmers'relevant knowledge, it is still applied to all kinds of crops. In recent years, peanut and fruit products exported from China have suffered huge losses because they have been found to contain long ingredients for many times. Therefore, the author especially reminds us that Bijiu related products are only used for flowers, lawns, trees and other plants unrelated to food. Uniconazole Other names: Uniconazole, S-3307D, nbspSumgaic, Prunit, S-327, XE-1019, XE-1019, etc. The chemical name of Uniconazole is (E)– (RS) -1- (4-chlorophenyl) -4,4-dimethyl-2- (1H-1,2,4-triazol-1-yl) pent-1-en-3-ol. The pure product is a colorless solid. The common dosage forms are 5%, 10% emulsifiable concentrate, 5% wettable powder and 0.08% granules. Uniconazole is a broad-spectrum and highly effective plant growth inhibitor, which can promote the dwarfing and strengthening of plants, and has certain bactericidal and herbicidal effects, and is a gibberellin synthesis inhibitor. Its biological activity is 2 to 6 times that of paclobutrazol. However, its residue in soil is only 1/10 of paclobutrazol, so it has little effect on succeeding crops. It can be absorbed by seeds, roots, buds and leaves, and transported among organs, but the outward transport of leaf absorption is less, and the apical property is obvious. It is mainly absorbed by leaves, stems and roots, and inhibits the biosynthesis of gibberellin. It is used for soil or foliar treatment, and has strong inhibitory activity on various monocotyledonous and dicotyledonous plants. Can be used in paddy field to resist lodging, control growth and promote tillering, promote root and increase leaves, strengthen seedlings, resist adversity and increase weight, and achieve high quality and high yield. It is used for potted plants such as chrysanthemum, poinsettia, azalea and other ornamental plants to control plant shape, promote flower bud differentiation and flowering. Can be use for fruit trees to control excessive growth of fruit tree branch. It can also be used for wheat, soybean, rape, peanut and other crops. It has the functions of controlling vegetative growth, inhibiting cell elongation, shortening internodes, dwarfing plants, promoting lateral bud growth and flower bud formation, and improving stress resistance. Promote the growth of stems, leaves, roots and fruits, break the apical dominance and prevent aging. It should be noted that the sowing rate of crops should be appropriate, too dense and too thin will affect the effect of growth control and tillering promotion; fertilizer and water management should keep up with it, and sufficient nutrients must be guaranteed in order to cultivate short and strong seedlings. Strictly control the amount and period of use. For seed treatment, the land should be leveled, shallow sowing and shallow covering, and the soil moisture should be good. When the seed quality is poor, Uniconazole should not be used to soak the seed. Germination should be accelerated after seed soaking with Uniconazole, and the seeds should be sown after full germination to facilitate seedling emergence. Preservative, drought-resistant agent and gametocide. 4. Preservative The main function of plant preservatives is to inhibit the respiration and metabolism of fruits and vegetables, reduce the activity of enzymes, control the expansion of latent diseases, the growth and reproduction of decay bacteria and the accumulation of toxic substances, and maintain the quality and freshness of fruits and vegetables. It mainly maintains the freshness of fruits, vegetables and flowers from the aspects of physiology and pathology, and prolongs the storage time. It can be divided into six categories according to the usage and the nature of the medicine: fruit washing agent, fruit soaking agent, fumigant, coating agent, Chinese herbal medicine decoction and adsorbent. According to its function, it can be divided into eight categories: ethylene remover, preservative, coating preservative, gas generator, gas regulator, physiological activity regulator, humidity regulator and so on. The following highlights several common preservatives: Other names of thiabendazole: also known as Tekeduo, Thiabendazole, Thiabendazole, etc. Chemical name of thiabendazole: 2- (thiazol-4-yl) benzimidazole. Junling technical is off-white or white tasteless powder, is stable in high-temperature and low-temperature water and acid and alkali liquor, is soluble in various organic solvents, has irritation to human skin, has low toxicity to human and livestock, and is safe to fish and bees. Normal use is not harmful to crops. The main formulations are 42% and 45% suspension concentrate, 60% and 90% wettable powder. Thiabendazole is a highly efficient, broad-spectrum, systemic microbial agent with protective and therapeutic effects, inhibiting the respiration and cell proliferation of pathogens. Has better control effect on diseases caused by ascomycetes, basidiomycetes and deuteromycetes. But not for Oomycetes and Zygomycetes. It is mainly used to treat fruits and vegetables after harvest. The application method comprises the following steps of: preventing and controlling the rot of oranges in the storage period, removing diseased, injured and inferior fruits after the oranges are harvested, soaking the oranges in a 45% suspending agent diluted by 450 to 900 times for 3 to 5 minutes, drying the oranges in the air, placing the oranges gently in a basket, and storing the oranges at room temperature, so that the control effect on Penicillium, green mold and stem rot is good. To prevent and control the decay of bananas during storage and transportation, bananas are soaked in 450 to 600 times diluent of 45% suspending agent for 1 to 3 minutes, and then the bananas are fished out, dried and packed. Before harvest, 67-130 grams of 45% suspending agent and 50 kilograms of water are sprayed per mu to prevent and control strawberry powdery mildew and gray mold. 40 to 100 grams of 45% suspending agent and 50 to 75 kilograms of water are sprayed per mu before harvesting to prevent and control Sclerotinia sclerotiorum, gray mold and spot blight of vegetables. To prevent and control blue mold, gray mold, anthracnose, scab and powdery mildew of apples, pears and grapes, 45% suspension concentrate 450-700 times diluted solution is sprayed before harvesting. To prevent and control mango anthracnose, the mango was soaked in 180 ~ 450 times diluted solution of 45% thiabendazole after harvesting. 90 milliliter of a 45% suspending agent and 30 kilogram of water are sprayed on each ton of potatoes to prevent and control that rot disease, the dry rot disease, the skin spot disease and the silver skin disease of the potatoes during the storage period. 30 to 60 milliliter of 5% suspending agent is mix with water for spraying per mu to prevent and control leaf spot of beet and peanut. In addition, the smoke agent can effectively prevent and control various fungal diseases of vegetables in the protected field, in the early stage of the disease, 300 to 400 grams of smoke agent is applied per mu, the smoke agent is evenly placed on the ground, a match is lit, the greenhouse is closed overnight, and doors and windows are opened for ventilation in the next morning. Precautions: (1) Excess liquid medicine after fruit soaking should be properly handled and should not pollute ponds and water sources. (2) Cannot be used on post-harvest tobacco. Do not mix with copper-containing agents. Other names for iprodione: Iprodione, Iprodione, Imazapyr, Isopropidine, Sandien, etc. Chemical name of iprodione: 3- (3,5-dichlorophenyl) -1-isopropylcarbamoylhydantoin. It is a white crystal, slightly soluble in water, easily soluble in organic solvents such as ethanol and benzene, and easy to decompose in alkali. Common formulations are: 50% WP, 25% SC. It is a common iprodione broad-spectrum protective fungicide, and has good effect on Botrytis, Neurospora, Sclerotinia, Sclerotinia and the like. Also has certain control effect on Alternaria, Helminthosporium, Rhizoctonia, Fusarium, Fuchsia and that like. The application method of the fresh-keeping agent comprises the following steps of: preventing and controlling the diseases of the oranges in the storage period; after the oranges are harvested, selecting disease-free fruits without mechanical damage; soaking the fruits in a liquid medicine of 1000 mg/L of 50% wettable powder or 25% suspending agent for 1 minute; fishing out and drying; and storing at room temperature to control the damage of green mold and green mold of the oranges. The storage time can be prolonged by storing in a refrigerator. In addition, iprodione is often used to control bacterial diseases of various vegetables, melons and fruits, and is a broad-spectrum contact fungicide. Can be used for preventing and treating pathogenic bacteria resistant to carbendazim, thiabendazole and the like. Precautions: (1) It should not be used continuously for a long time to avoid drug resistance. (2) It should not be mixed with alkaline pesticides to avoid decomposition and failure. Other names of imazalil: diazolidone, imazalid, imazalil, etc. The chemical name of imazalil is 1-2- (2,4-dichlorophenyl) -2- (2-allylchloro) ethyl-1H-imidazole. The technical product (98.5% of active ingredient) is a yellow to brown crystalline solid. Slightly soluble in water, easily soluble in organic solvents. Stable at room temperature and away from light. Non-corrosive to metal and plastic. The common dosage forms were 22.2% and 47.2% EC. Imazalil is a systemic broad-spectrum fungicide. Its function is to interfere with the permeability of pathogen cell membrane, ester synthesis and metabolism, and has special effects on fungal diseases such as longibrachiella, Fusarium and Septoria. Penicillium and Penicillium resistant to benzimidazoles are highly effective. It is mainly used for preservation of citrus, banana and other fruits. Can also be use as a seed treatment agent, a stem and leaf control agent and a preservative after harvest for crops such as cereals, melons, vegetable and that like. The application method comprise that following step of: preventing fruit rot (Penicillium, Penicillium and stem rot) of oranges, bananas and the like, and preserve the fruits according to the picking quality and the storage period of the fruits, generally preparing a concentration of not less than 200 mg/L, namely using 5 milliliters of 47.2% emulsifiable concentrate, adding 12.5 kilograms of water, adding 2,4-D with a concentration of 100 to 200 mg/L, and soaking for 1 to 2 minutes. And then taking out, drying, packaging and storing. 10 to 60 milliliters of 47.2% emulsifiable concentrate and 100 kilograms of water are uniformly sprayed to prevent and control the rot of vegetables and ornamental crops and keep the vegetables and ornamental crops fresh. To prevent and control cereal smut, use 8 to 10 milliliters of 47.2% emulsifiable concentrate mixed with 100 kilograms of cereal seeds. Precautions: (1) For the oranges treated with the liquid medicine, pay attention to ventilation and properly handle the remaining liquid medicine for fruit soaking and preservation within a few days after storage, so as to prevent environmental pollution. (2) Pay attention to safety during use to prevent the liquid medicine from contacting the skin and eyes. If the liquid medicine contacts the skin and eyes, it should be washed with a large amount of clean water immediately and sent to the hospital for treatment. If it is poisoned by mistake, it should be treated symptomatically. There is no specific antidote. And (3) when that agent is mix with carbendazim, thiabendazole, carboxin, thiophanate-methyl and other pesticides, the disease control effect dure storage can be improved. Other names of carbendazim: Benzimidazole No.44, Mianweiling, Mianweidan, Baoweitian, etc. Carbendazim is the most widely used and common fungicide at present, and it is also commonly used in the preservation of fruits and vegetables. The chemical name of carbendazim is methyl N- (2-benzimidazolyl) carbamate. Its pure product is a white tasteless solid, soluble in water, soluble in alcohol and other organic solvents. It is unstable to acid and alkali and soluble in dilute acid. Its common preparations are 50% and 25% wettable powder. Carbendazim is a kind of benzimidazole, which is a systemic broad-spectrum fungicide. It is effective against many diseases caused by ascomycetes and imperfect fungi, but ineffective against diseases caused by oomycetes and bacteria. Its mechanism is mainly to interfere with the formation of spindle in the mitosis of bacteria, thus affecting cell division. Apple and pear scab, anthracnose, ring rot, peach brown rot, scab, grape black spot, anthracnose, citrus scab and yellow spot can be controlled by spraying 1000 times of 50% wettable powder. As a preservative, the fruit can be soaked in 1000 times of 50% carbendazim for 10 minutes before packaging, taken out and dried before packaging, which will have a better preservative and fresh-keeping effect. Precautions: (1) It should not be mixed with copper preparations. (2) There is cross-resistance between the agent and thiophanate methyl, so attention should be paid when using it. (3) The safety interval is 15 days. Thiophanate-methyl Other names: Thiophanate-methyl. The chemical name of thiophanate methyl is 1,2-bis (3-methoxyl-2-thioureido) benzene. The technical product is a colorless crystal, insoluble in water, soluble in organic solvents, and stable to acid and alkali. Common formulations are 50%, 70% WP, 10% EC, 50% SC, 36% SC. The medicine is a benzimidazole broad-spectrum bactericide and has systemic, preventive and therapeutic effects. It is often used for antiseptic storage of bananas, oranges, pineapples, Hami melons, apples, sweet potatoes, etc. Carbendazim suspension with a concentration of 500 ~ 2000mg/kg is generally used for dipping or coating treatment. Sometimes it should be mixed with 200mg/kg 2,4-D. In addition, the agent has low toxicity to people, livestock, bees and fish, is safe to crops, and can be used for preventing and treating various fungal diseases such as Sclerotinia sclerotiorum, gray mold, powdery mildew and the like on fruits and vegetables. Precautions: (1) It should not be mixed with copper preparations or alkaline drugs. (2) There is cross-resistance between this product and carbendazim, so attention should be paid when using this product. (4) The safety interval is 15 days. 5. Drought resistant agent Drought-resistant chemicals are chemical substances produced by chemical means to inhibit soil water evaporation, promote crop root water absorption or reduce transpiration intensity. At present, there are mainly three types of drought-resistant chemicals used in research and production, including chemical mulching agent, water-retaining agent and antitranspirant. For chemical water-saving, a lot of research has been done abroad, which has attracted wide attention in Japan, France, India and other countries. Chemical mulching has been applied in agriculture successively, and the effect of increasing production is very good. The application of chemicals can improve soil water retention capacity and reduce crop transpiration loss. At present, the application of drought-resistant agent is less in the actual production in China, and the scope of use is also smaller. The development of new water-retaining agent and antitranspirant is also relatively small, except for a small number of varieties of fulvic acid (FA) drought-resistant agent to achieve industrialization, more still exist in the theoretical and experimental stage. The water-retaining agent is a strong water-absorbing resin composed of the same molecules, which can absorb water hundreds to thousands of times of its own weight in a short time. The water-retaining agent is directly applied to the soil by seed coating, seedling root dipping, or furrow application, hole application, or ground spraying, just like building a small reservoir for seeds and crop roots. It can absorb water in the soil and air, and store rainwater in the soil. In case of drought, the stored water can be released slowly for seed germination and crop growth. At present, the widely used antitranspirant is fulvic acid (FA), which is extracted from weathered coal. In 1979, relevant researchers in Henan began to use it in actual production and achieved good results. Some manufacturers, with the trade name of “drought-resistant agent No.1”, can effectively control the opening of stomata and reduce leaf transpiration. It can effectively resist the damage of seasonal drought and dry and hot wind. Once sprayed, the effect lasts for 10-15 days. In addition to foliar spraying, it can be used for seed dressing, seed soaking, root irrigation and root dipping, etc. To improve the germination rate of seeds, promote the development of root system, shorten the seedling recovery period of transplanted crops and improve the survival rate. 6. Male sterilant Male gametocide is mainly used in agricultural cross breeding production, which is used to remove the stamen of the female parent. Male sterility is often used in cross breeding in production practice. However, there are few varieties with male sterility, which limits the scope of cross breeding. In addition, the method using manual emasculation is very troublesome and has poor reliability. The birth of gametocide has found an effective way for cross breeding, which has been paid attention to by breeders. Its principle of action is mainly to block the development of plant pollen, inhibit the elongation and glume opening of plant ears, prevent the meiosis of pollen cells or induce self-incompatibility, so as to make pollen lose the ability of fertilization and achieve the purpose of direct fertilization (emasculation). Its self-pollination is inhibited, thus providing convenience for cross-pollination to obtain plant hybrid seeds. Commonly used types of gametocide are methyl arsenate, sulfamic acid, halogenated fatty acids and so on. The products used to kill male in wheat are Jinaolin, Xiongzhexin, Xiongdadine, Xiongdazone, Xiong-532 and so on. The male gametocide products used in rice include sulfamic acid, male gametocide No.2, androxidin, androxidin, etc. The gametocide products used in corn include androcide, androcide and so on. 7. Compound growth regulator According to its function, it can be divided into the following categories: 1) Rooting agent: It is mainly used to promote the rooting and seedling recovery of seedlings after transplanting, or the cutting of seedlings. The types are auxin + Tujunxiao, auxin + catechol, indoleacetic acid + naphthylacetic acid, auxin + saccharin, abscisic acid + auxin, fulvic acid + indolebutyric acid, etc; And 2) that fruit set promoting agent has the function of improving the parthenocarpy rate, improving the single weight of the fruit, promoting the fruit set, accelerating the expansion speed of the fruit and increasing the size of the fruit. Gibberellin + cytokinin, gibberellin + auxin + 6-BA, gibberelin + 1-naphthoxyacetic acid + carbanilide, gibbetrellin + kanamycin, gibbetrelin + brassinolide, and gibberrellin plus 1-naphthoxyacetic acid + trace element; 3) Inhibitory fruit-setting agent and grain yield-increasing agent: its function is to control vigorous growth and improve fruit-setting rate. Chlormequat chloride + choline chloride, chlormequat chloride + ethyllisole, ethyllisole + abscisic acid, chlormequat chloridum + ethylisole + cupric sulfate, cycocel + pyrimidinol, cycocel + gibberellin, abscisic acid + gibberellin and so on. And 4) dormancy-breaking growth-promoting agent: that dormancy-breaking growth-promoting agent has the function of break dormancy and promoting germination. The types include gibberellin + thiourea, potassium nitrate + thiourea, benzylaminopurine + naphthylacetic acid + nicotinic acid, gibberellin + KCl, Gibberella + Fospinol, etc. 5) Drying and defoliating agent: It is mainly used for drying and defoliating sesame and cotton before mechanical harvesting. Its function is not only the effect of drying and defoliation, but also the effect of increasing yield. The types are ethidium + paraquat, thiazolon + methamidophos, thiazolon + potassium carbonate, ethidium + ammonium persulfate, thiazolone + diuron, ethidum + caudosol + cycloheximide and so on. And 6) a ripening and coloring quality improving agent, which has the functions of accelerating the ripening of the fruit, brightening the color, increasing the sweetness of the fruit and the like. The types include ethidium + triamcinolone, ethidium + cyclodextrin complex, ethidium plus 2,4,5-propionic acid, diuron plus citric acid, benzylaminopurine plus kasugamycin, etc. 7) Vegetable, fruit and fruit picking agent: it is applied before apple and citrus are almost ripe to promote the formation of abscission layer at the base of citrus fruit stem, thus leading to the separation of fruit and branch. The types are: naphthylacetamide + ethenylsalicylic acid, dinitro-o-cresol + naphthylacetamide + ethenylsalicylic acid, naphthyl-acetamide + carbaryl, dinitro-o-cresol + naphthyl-acetamid. And 8) promoting flower bud development, flowering and sex ratio, namely transforming the vegetative growth of the fruit crops into the reproductive growth, and promoting flowering. Its types include naphthylacetic acid + benzylaminopurine, benzylaminopurine + gibberellin, gibberellin + silver sulfate, ethenolide + potassium dichromate, etc. 9) Sprout inhibitor: It can inhibit the germination of axillary buds on tobacco and inhibit the germination of potatoes during storage. The types include Qingxiansu + Yiyamin, chlorpropham + chlorpropham, sucrose fatty acid ester + Qingxiansu, etc. 10) growth-promoting and yield-increasing agent: it can improve the absorption of N, P and K by plants and increase the yield. The types include indoleacetic acid + naphthylacetic acid, indoleacetic acid + naphthylacetic acid + 2,4-D + gibberellin, mepiquat chloride + cytokinin + auxin, hydrogen peroxide + wood acetic acid, etc. 11) Stress resistance agent (drought resistance, low temperature resistance, disease resistance, etc.): increase the absorption of nutrient elements, promote the growth of seedlings, increase the total amount of dry matter, and improve the cold resistance, drought resistance, disease resistance and insect resistance. The types include anti-kinetin + abscisic acid, cytokinin + auxin + gibberellin, ethenolide + gibberellin, salicylic acid + gene activator, etc. 11) Stress resistance agent (drought resistance, low temperature resistance, disease resistance, etc.): increase the absorption of nutrient elements, promote the growth of seedlings, increase the total amount of dry matter, and improve the cold resistance, drought resistance, disease resistance and insect resistance. The types include anti-kinetin + abscisic acid, cytokinin + auxin + gibberellin,cbd crystallization equipment, ethenolide + gibberellin, salicylic acid + gene activator, etc. Return to Sohu to see more Responsible Editor:. toptiontech.com