China Garden Network News: Plant growth regulators are exogenous substances with physiological activities of plant hormones that are artificially synthesized and extracted. Some of them can move within plants, such as anti-fall hormone and paclobutrazol, while others have poor mobility or cannot move at all, such as clopidourea and 6-benzylaminopine. Plant growth regulators can be classified into three major categories based on their mode of action: plant growth promoters, plant growth retarders and plant growth inhibitors.
Plant growth promoter
At appropriate concentrations, it can promote the division and elongation of plant cells, the differentiation and formation of new organs, and prevent fruit dropping, etc.
Gibberellin (GA), also known as 920, has trade names such as Qibao, Ruixuebao, and Jingge. Dosage forms include powder, soluble tablets, emulsifiable concentrate, ointment, wettable powder, etc. Low toxicity, safe for humans, livestock and bees.
At present, more than 70 kinds of gibberellins have been isolated from higher plants and microorganisms by humans. Among them, GA3, GA4, GA7 and others have relatively high activity. Among them, GA3 has the highest activity among gibberellins and can significantly promote the growth of plant stems and leaves, especially showing obvious promoting effects on genetic and physiological dwarf plants. It can replace the light and low-temperature conditions required for the germination of certain seeds and promote seed germination. It can enable long-day plants to flower under short-day conditions and shorten their growth cycle. It can induce flowering and parthenocarpy, and promote fruit growth.
Note 1: Pure gibberellin has low water solubility. Before use, 85% or 75% crystalline powder should be dissolved in a small amount of alcohol first, and then diluted with water to the required concentration.
Gibberellin is not easily decomposed in a dry state, and the agent should be stored in a dry place. Its aqueous solution is prone to destruction and failure when the temperature is above 5℃. It is prone to decomposition when exposed to alkali and should not be mixed with alkaline pesticides or fertilizers. It is advisable to prepare and use it immediately.
When used in combination with foliar fertilizers, it is more conducive to forming strong seedlings. When used alone or in excessive amounts, it may cause side effects such as slender and weak plants and inhibition of root growth.
2. Antiloressin (4-CPA, PCPA), also known as p-chlorophenoxyacetic acid, is commercially called Tomato Spirit. The dosage forms include liquid and soluble powder. It is of low toxicity to humans and animals.
As an systemic plant growth regulator, it can be absorbed through roots, stems, leaves, flowers and fruits, and its biological activity lasts for a long time. It has functions such as promoting growth, preventing the formation of delamination, promoting fruit setting and inducing parthenocarpy.
Note 1: The concentration of the pesticide application is related to the temperature. When the temperature is low, the amount of water should be reduced; when the temperature is high, the opposite is true.
2. This product is sensitive to the tender shoots and young leaves of seedlings. When spraying, the concentration must be strictly controlled and repeated spraying is not allowed. Spray in the morning or evening on sunny days to avoid pesticide damage. If pesticide damage occurs, increase the supply of fertilizer and water.
3. The combination of anti-drop agent and 0.1% potassium dihydrogen phosphate has a synergistic effect.
Iii. 2, 4-drop (2,4-D) has trade names such as Qiu Shi, etc. The dosage forms include salt powder and liquid, etc., with moderate toxicity.
The application of 2,4-D has the effect of promoting at low concentrations and inhibiting at high concentrations. When the usage concentration is between 2 milligrams and 20 milligrams per kilogram, it can promote cell elongation and stimulate growth. Promote root development; Promote germination and maintain apical dominance. When the concentration exceeds 100 milligrams per kilogram, it has a selective killing effect on dicotyledonous plants or hinders their growth.
Note 1: It is a herbicide in large doses. When using it for the first time, try to conduct a small-scale test.
When used to promote root growth, mixing it with indolebutyric acid can enhance the effect.
Four. Indolebutyric acid (IBA) has trade names such as Genwang and Genduozhuang. The dosage form is mostly powder. It is non-toxic to humans and livestock and readily degradable in soil.
It is widely used in production as a rooting agent, which can promote the rooting of cuttings, induce the formation of adventitious roots, and increase the survival rate of transplanting. Because it is not easy to move, the methods of dipping and soaking the cuttings are mostly adopted. It is often mixed with naphthalene acetic acid for use. The former increases the number of adventite roots, while the latter promotes the thickening of the root system.
Note 1: When handling cuttings, do not contaminate the leaves and heart leaves.
2. Indolebutyric acid is prone to decomposition when exposed to light and should be packaged in black materials. It should not be stored for a long time.
V. Naphthalene acetic acid (NAA) has trade names such as Guonongfeng and Haoxi. Mostly in liquid and powder forms. It is of low toxicity to humans and animals and non-toxic to bees.
Apply to promote root growth and increase the survival rate of transplanting. It is not afraid of light or heat, and is not easily degraded after being absorbed by plants. Moreover, its medicinal properties are mild and it will not cause the phytotoxicity that is prone to occur during the root promotion of 2,4-D. The promoted root system is thick and straight, but in small quantities. The effect is better when used in combination with indolebutyric acid. Low concentrations inhibit the formation of delamination, while high concentrations promote it.
Note 1: The original powder of naphthalene acetic acid is insoluble in cold water. It can be dissolved in a small amount of alcohol first and then diluted with water.
2. It has a good effect on the rooting of cuttings, but when used alone at a higher concentration, it has the side effect of inhibiting the growth of above-ground branches.
Six. Ethephon, also known as Yishi Ling or ethylene Phosphorus, has trade names such as Shu Mei Feng, Mian Tao Xiao, and Chan Wang. The dosage forms include aqueous solutions and wettable powders. It is of low toxicity to humans and animals.
When applied into plants, ethylene can be released under the action of cell SAP. It can promote fruit ripening, induce male sterility, reduce apical dominance, increase effective tillering, dwarf plants and prevent lodging.
Note 1: Ethephon is stable in solutions with a pH value less than 3.5. When the pH is above 4.5, it will decompose and release ethylene. The higher the pH value, the faster the release. Therefore, it should not be mixed with alkaline pesticides or fertilizers.
2. Etheylidene concentrate is a strongly acidic liquid that can irritate and corrode the skin, mucous membranes and eyes. It can produce flammable and explosive gases when exposed to alkali. Use it with caution.
Heptadecylanols are also known as bee flower alcohol or wax alcohol. There are emulsions, water emulsions, wettable powders, etc. Natural product, non-toxic to humans and animals.
Broad-spectrum plant growth regulators can be absorbed by the stems and leaves of plants. High concentrations have an inhibitory effect, while low concentrations have a promoting effect. It can promote seed germination and root growth, and enhance the cold resistance of dryland crops. Increase chlorophyll content, enhance the intensity of photosynthesis, and cultivate healthy plants; Promote the rooting of cuttings. Soaking the cuttings in a trisanol solution of 1 to 5 milligrams per kilogram for 8 to 12 hours can significantly promote root growth and increase the survival rate of cuttings.
Note 1: Try to use it in the afternoon on a sunny day. The suitable temperature is 20℃ to 25℃. Do not use it when the temperature is above 30℃ or below 10℃. If it rains within 6 hours after spraying, spray half the amount and reapply once.
2. Strictly control the dosage to avoid drug damage.
3. Trisanols sold on the market may have precipitates or crystals. Shake well or heat with hot water until completely dissolved before use to avoid local concentration being too high and causing phytotoxicity.
Viii. The trade names of benzylaminopine (BAP) include Shengwang and Nongshiduo, etc. There are various dosage forms such as solubilizable agents, emulsions and emulsifiable concentrates, which are safe for both humans and animals.
The application can be absorbed by the stems, leaves, fruits, buds and flowers of plants, promoting cell division and growth. Break the apical dominance and promote the germination of lateral buds.
Note 1: When used for flower and fruit retention and increasing the weight of individual fruits, it has a synergistic effect when combined with gibberellin.
Ix. The trade names of sodium nitrophenolate include Ai Duo Shou, Bi Shou Feng, Shou Feng Jia, etc. Mostly in liquid form and soluble powder form, it is of low toxicity to humans, livestock and fish.
Seed treatment can increase the germination rate and promote root growth. Seedling treatment can shorten the acclimation period after transplantation and increase the survival rate of transplantation. When plants encounter drought, low temperature, pests and diseases, and pesticide damage, spraying or irrigating sodium nitrophenolate solution can enhance the stress resistance of the affected plants.
Note 1: Strictly control the dosage and do not use at high concentrations.
2. When mixed with fungicides and fertilizers, it has a synergistic effect.
3. It has a relatively strong alkalinity. Before being mixed with acidic pesticides or fertilizers, a small-scale test should be conducted first.
X. The trade names of aminostearic acid (DA-6) include High Yield and Plant Dragon, etc. The dosage forms include soluble powder, liquid, etc., which are of low toxicity to humans and animals.
It can increase the photosynthetic rate, enhance the metabolism of carbon and nitrogen in plants, strengthen the absorption of water and nutrients by plants, regulate the water balance within plants, and thereby improve the drought and cold resistance of plants.
Note 1: It is prone to decomposition when exposed to alkali and should not be mixed with alkaline pesticides or fertilizers.
2. Do not spray under high temperatures or direct sunlight. It is more effective to spray after 4 p.m. If it rains 6 hours after spraying, the amount should be halved for re-spraying. It should not be used too frequently. The interval should be at least one week.