Plant growth regulators are synthetic and extracted exogenous substances with physiological activity of plant hormones. Some of them can be moved in plants, such as clostridin, paclobutrazol, and others have poor mobility or cannot move, such as clopidomide, 6-benzylaminopurine, etc. According to the mode of action, plant growth regulators can be divided into three categories: plant growth promoters, plant growth retardants and plant growth inhibitors.

At the appropriate concentration, plant growth promoters can promote plant cell division and elongation, differentiation and formation of new organs, and prevent fruit falling off.

1、 The dosage forms of gibberellin (GA) include powder, soluble tablet, emulsifiable oil, paste, wettable powder, etc. Low toxicity, safe for people, livestock and bees.

Application Now more than 70 kinds of gibberellins have been isolated from higher plants and microorganisms, and GA3, GA4 and GA7 have higher activity. Among them, GA3 has high activity in gibberellins and can significantly promote the growth of plant stems and leaves, especially for dwarf plants of genetic and physiological types; It can replace the light and low temperature conditions required for some seeds to germinate and promote seed germination; It can make long-day plants bloom under short-day conditions and shorten the growth cycle; It can induce flowering and parthenocarpy and promote fruit growth.

be careful

1. The water solubility of pure gibberellin is low, and 85% or 75% crystalline powder is dissolved with a small amount of alcohol before use, and then diluted with water to the required concentration.

2. Gibberellin is not easy to decompose in dry state, and the agent should be stored in a dry place. When the water solution is above 5 ℃, it is easy to be damaged. It is easy to decompose in case of alkali, and cannot be mixed with alkaline pesticides or fertilizers. It should be prepared and used as soon as possible.

3. It is more beneficial to form strong seedlings when combined with foliar fertilizer. Single use or excessive use will produce side effects such as thin and thin plants and inhibition of rooting.

2、 PCPA (4-CPA, PCPA) is also known as p-chlorophenoxyacetic acid. The dosage forms include water and soluble powder. Low toxicity to people and animals.

As an endogenous plant growth regulator, it can be absorbed by roots, stems, leaves, flowers and fruits, and its biological activity lasts for a long time. It has the functions of promoting growth, preventing the formation of separation layer, promoting fruit setting and inducing parthenocarpy.

be careful

1. The application concentration is related to the high and low temperature. The low temperature will reduce the water volume, while the high temperature will decrease the water volume.

2. This product is sensitive to tender shoots and young leaves of seedlings. The concentration should be strictly controlled when spraying, and repeated spraying is not allowed. Spray in the morning and evening on sunny days to avoid drug damage. In case of drug damage, strengthen the supply of fertilizer and water.

3. The mixture of anti-colourin and 0.1% potassium dihydrogen phosphate has synergistic effect.

3、 The 2,4-drop (2,4-D) dosage form includes salt powder and water, with moderate toxicity.

The application of 2,4-D has the effect of low concentration promotion and high concentration inhibition. When the concentration is between 2 mg and 20 mg/kg, it can promote cell elongation and stimulate growth; Promote root development; Promote germination and maintain top advantage. When the concentration is higher than 100 mg/kg, it can selectively kill dicotyledonous plants or hinder the growth of plants.

be careful

1. It is a herbicide at a large dose. The first use should be conducted in a small area.

2. When it is used to promote rooting, it can be mixed with indobutyric acid to improve the effect.

4、 The dosage form of indobutyric acid (IBA) is mostly powder. It is non-toxic to humans and animals and easy to degrade in soil.

It is widely used in production as rooting agent, which can promote rooting of cuttings, induce the formation of adventitious roots, and improve the survival rate of transplanting. Because it is not easy to move, dip and soak the insert. It is often mixed with naphthylacetic acid for use. The former increases the number of adventitious roots, and the latter promotes the growth of roots.

be careful

1. When handling cuttings, do not stain the leaves and heart leaves.

2. Indobutyric acid is easy to decompose when exposed to light, and needs black packaging, and should not be stored for a long time.

5、 Naphthylacetic acid (NAA) is mostly water and powder. It is low toxic to humans and animals, and non-toxic to bees.

The application of rooting promotion can improve the survival rate of transplanting. It is not afraid of light and heat. It is not easy to be degraded after being absorbed by plants, and the drug property is mild. It will not produce the drug damage that is easy to occur when 2,4-D promotes roots. The promoted roots are thick and straight, but the amount is small, and the effect is better when combined with indobutyric acid. Low concentrations inhibit the formation of the ionosphere, while high concentrations promote the formation of the ionosphere.

be careful

1. Naphthylacetic acid raw powder is difficult to dissolve in cold water. It can be dissolved with a small amount of alcohol and then diluted with water.

2. It has good effect on rooting of cuttings, but higher concentration alone has the side effect of inhibiting the growth of aboveground branches.

6、 Ethephon is also known as Yitrialing and ethephon. The dosage forms include water and wettable powder. Low toxicity to people and animals.

When applied into plants, ethylene can be released under the action of cell fluid. It can promote fruit ripening, induce male sterility, reduce apical dominance, increase effective tillers, dwarf plants, and prevent lodging.

be careful

1. Ethephon is stable in the solution with pH<3.5. When the pH is above 4.5, it will decompose and release ethylene. The higher the pH is, the faster the release is. Therefore, it cannot be mixed with alkaline pesticides or fertilizers.

2. Ethenol stock solution is a strong acidic liquid, which has irritating and corrosive effects on skin, mucous membrane and eyes. It will produce flammable and explosive gas in case of alkali, so it should be used carefully.

7、 Triacontanol is also known as propolis alcohol and wax alcohol. There are emulsions, water emulsions, wettable powders, etc. Natural products are non-toxic to humans, animals and animals.

Broad-spectrum plant growth regulators can be absorbed by plant stems and leaves. High concentration has inhibitory effect, while low concentration has promoting effect. It can promote seed germination and rooting, and enhance the cold resistance of dryland crops; Increase the content of chlorophyll, enhance the intensity of photosynthesis, and cultivate robust plants; Promote cutting and rooting. Soaking cuttings with 1 mg to 5 mg/kg triacontanol solution for 8 to 12 hours can significantly promote rooting and improve the survival rate of cuttings.

be careful

1. Try to use it in the afternoon on a sunny day. The appropriate temperature is 20 ℃ to 25 ℃. Do not use it if it is above 30 ℃ or below 10 ℃. In case of rain within 6 hours after spraying, the spraying shall be reduced by half and supplemented once.

2. Strictly control the dosage to avoid drug damage.

3. The triacontanol sold on the market may have precipitates or crystals. Shake it well or warm it with hot water until it is completely dissolved before use, so as to avoid drug damage caused by excessive local concentration.

8、 Benzaminopurine (BAP) is safe for human and livestock because of its solvable, emulsion, emulsifiable oil and other dosage forms.

The application can be absorbed by the stems, leaves, fruits, buds and flowers of plants to promote cell division and enlargement. Break the top advantage and promote the lateral bud germination.

Note 1. When used to protect flowers and fruits and increase the weight of single fruit, it has synergistic effect with gibberellin.

9、 Sodium nitrophenolate is mostly water and soluble powder, which is low toxic to human, livestock and fish.

Applying seed treatment can improve germination rate and promote rooting. Seedling treatment can shorten the slow seedling stage of transplanting and improve the survival rate of transplanting. When plants encounter drought, low temperature, diseases and insect pests and drug damage, spraying or irrigation with sodium nitrophenol solution can enhance the resistance of the affected plants.

be careful

1. The dosage should be strictly controlled and should not be used at high concentration.

2. It can be mixed with bactericide and fertilizer to enhance efficiency.

3. Because of its strong alkalinity, it should be tested on a small scale before being mixed with acid pesticides or fertilizers.

10、 The dosage forms of DA-6 include soluble powder and water, and are low toxic to humans and animals.

It can improve the photosynthesis rate, carbon and nitrogen metabolism of plants, enhance the absorption of water and fertilizer by plants, and regulate the water balance in plants, so as to improve the drought and cold resistance of plants.

be careful

1. It is easy to decompose in case of alkali and cannot be mixed with alkaline pesticides and fertilizers.

2. Do not spray in the hot sun. The spraying effect is better after 4pm. If it rains 6 hours after spraying, the spray shall be reduced by half. It should not be used too frequently, and the interval should be at least one week.

Plant growth retarder

Plant growth retardants can shorten plant internodes, induce dwarfing and promote flowering, but they have relatively no effect on leaf size, leaf number, node number and apical dominance.

1、 CCC is also known as triclosan and chlorocholine chloride. The dosage forms mainly include water and soluble powder, which are low toxic to humans and animals and harmless to bees.

Application inhibits cell elongation and growth by inhibiting the biosynthesis of endogenous gibberellin, but does not inhibit cell division. Generally, foliar spraying is used, with the concentration of 1000 mg to 3000 mg/kg.

be careful

1. The activity will decrease under high temperature, so the concentration or the number of times of application should be appropriately increased. The seedlings with the tendency of overgrowth have better effect, and the plants with weak growth are not suitable for use.

2. Chlormethrin is easily soluble in water, has strong hygroscopicity, and can be decomposed in case of alkali. It cannot be mixed with alkaline pesticides and fertilizers.

3. Chlormethrin is easy to be decomposed by soil microorganisms. When soil application or irrigation is adopted, it often only plays half of its activity in the soil, so the effect of soil application is not good.

4. Spraying on the leaves can easily cause temporary yellow spots on the tip of leaves, especially for ornamental seedlings. This problem can be solved by reducing the concentration and reusing.

2、 Melamine is also known as prozotocin, regulatory pyridine, methylpyridine, etc. The dosage forms include soluble powder, water, emulsion, etc., which are harmless to humans and animals, and have no irritating effect on eyes and skin.

It is easy to conduct when applied in plants and can inhibit the formation of gibberellin, thus inhibiting the elongation of plant cells and weakening the apical advantage.

be careful

1. Strictly control the time and dosage of the drug. If the drug is used too early or too heavily, it will affect the normal growth of plants and even cause drug damage. In case of excessive inhibition, 100 mg to 500 mg/kg gibberellin solution can be sprayed according to the severity of the occurrence to reduce or remove the drug damage.

2. Melamine is easy to dissolve in water and decompose in case of moisture. It should be prepared and used immediately. The prepared solution should not be kept for a long time. The unopened finished products shall be stored in a dry, cool and ventilated place.

3、 PP333 is also known as Clonidazole. The dosage forms include suspending agent, emulsifiable oil, wettable powder, etc., which are low toxic to humans, livestock, fish and birds.

The application enters the plant body through roots, stems and leaves, and absorbs quickly with tender shoots and tip. It can inhibit the apical dominance, promote the growth of lateral buds, facilitate the formation of short fruit branches, and make the tree dwarf and compact. Suppress stem elongation, shorten internode and reduce lodging. At the same time, it can also promote tillering, increase the diameter of roots, the number of lateral roots and absorbed roots, enhance photosynthesis, and have antibacterial and bactericidal activities against some pathogenic fungi such as white rot, bacterial wilt, sheath blight, etc.

be careful

1. The dwarfing effect is significantly stronger than that of chlormequat, and it can be significantly effective once or twice, but excessive application will cause the plant to stop growing.

2. After application, the leaf color of the plant becomes significantly darker, which is easy to cause the illusion of sufficient fertilizer and water. Therefore, after application, it is necessary to strengthen the management of fertilizer and water, and add nitrogen and potassium fertilizer to prevent premature senescence of branches and leaves. The plant should not be used due to poor growth.

3. Under high temperature and high humidity, the concentration or frequency of medication can be appropriately increased.

4. The residual period of paclobutrazol in the soil is long. When the application plot is used again, it should be ploughed to avoid inhibiting the subsequent crop.

5. In case of excessive use, the plant can be restored by applying urea or gibberellin.