Key technology of using plant growth regulator
Control working concentration and dosage
When using the plant growth regulator, we should pay attention to the dosage. This is because dosage will have influence on the effect and cost of plant growth regulator as well as the environmental safety. Some regulators may have completely opposite effect under different concentrations. For example, low concentration of auxin will promote growth and high concentration will inhibit growth and even kill the plants. When using the plant growth regulator, the concentration and liquid amount should be controlled strictly. In order to achieve good regulation effect, the dosage should be reduced as many as possible so as to reduce cost and residue. Under general conditions, if the plant growth regulator is sprayed one time in the critical period, it will have obvious effect. By spraying it in many times, it will not only take a lot of work and medicine, but also will not have good effect. However, when using plant growth retardants, by using it many times with low concentration, the effect will be better than using it one time with high concentration. This is because by using the former method, it can not only keep continuous inhibitory effect, but also can prevent toxic and side effect on plants.
The physiological effect of plant growth regulator is always related to certain growth and development periods. Therefore, if it is used too early or too late, it cannot achieve ideal effect. Besides, by using it in different periods, it may even have opposite effects. For example, by using NAA in the young fruit period, it can protect fruit set; however, when it is used before fruit picking period, it can prevent fruit drop. Therefore, plant growth regulator should be used in proper period. It can be used before 10 a.m. in sunny and calm days and should not be used in rainy days. If it rains after spraying the medicine in 4h, it should be sprayed again.
Choose the plant growth regulator according to the reactions of different crops, varieties and organs
As different crops, varieties and organs will have different sensitivity to regulators, we should choose regulators and working concentrations properly. For example, as apricot is sensitive to MET, the dosage should be increased; besides, MET should not be used in prunus salicina. Therefore, we should choose the plant growth regulator according to the reactions of different varieties.
Use proper dosage form and application process
Plant growth regulator mainly includes technical material, water aqua, powder, oil solution, fumigant and other dosage forms. The application methods generally include mist spray, soaking, smearing, pouring, dropping, fumigating and so on. Technical material is usually insoluble in water, which can only be used after diluted by relevant solvent. When the water aqua is sprayed on the blade surface, a certain amount of surfactant will be added (such as soapy water, washing powder and so on, but they should not largely change the liquid PH value), thus it can be easy to adhere and spread on the blade surface. As turbid liquid that is made by wettable powder will have poorer uniformity than water aqua, it should be shook when being sprayed so as to avoid precipitation. Proper application process should be chose according to the action mode of plant growth regulator in the plant body. For example, as MET is absorbed through the root system, it can be sprayed in the soil; when using 2,4-D on preventing blossom drop and fruit drop, it should be smeared on the flower so as to inhibit the formation of separation layer, however, if it is used on the young leaves, it will be easy to cause damages; when stimulating the blossom of pineapples by using NAA or ethephon, they should be poured into the tubular interior leaves instead of irrigating or spraying it on the soil, thus it can directly stimulate the inflorescence differentiation.
Cleanly wash the container before using it in preparing agentia
As different regulators will have different PH value and other physicochemical properties, containers that used in preparing agentia should be kept clean. When acidic reagent is filled in the container that has been filled with alkaline reagent without cleaning, it will lose effect; if the container has been filled with inhibitor and is filled with accelerant again, they will not have good effect. For example, as maleic hydrazide that used in the agricultural production often has high concentration, if the container is used in filling other pesticides without cleaning, it may cause fallen leaves and fruit drops.
Pay attention to growth states and climate changes
Generally speaking, high concentration can be used on plants that have good growth states, while low concentration can be used on plants that have poor growth states. Temperature will also have important influence on the regulators, this is because when the temperature is higher, the reaction rate will be faster; when the temperature is lower, the reaction rate will become slower accordingly. Therefore, different concentrations should be respectively used in winter and summer. Under dry weather conditions, the concentration should be reduced. On the contrary, the concentration should be increased when the rainwater is abundant.
Mix various agentias skillfully and carefully
By mixing various plant growth regulators or mixing them with pesticide and chemical fertilizer, they will have aggregate utility and solve some problems that exist in the production. For example, in order to shift the supply period of pear to an earlier time, ethephon can be mixed with NAA when they are used in ripening so as to prevent fruit drop; however, when mixing various plant growth regulators or mixing them with pesticide or chemical fertilizer, we should fully understand whether there exists potentiation or antagonism between the plant growth regulators or plant growth regulator and other pesticides. For example, as some pesticides have acidity, they should not be mixed with alkaline pesticide or fertilizer; gibberellin will be easy to dissolve when encountering with alkali; when mixing maleic hydriazide with cytokinin, the effect will be counteracted.
Carry out small-scale test
As pesticides will be influenced by climate, growth regulator quality and dosage form as well as other factors, they should not be used according to the unified standard. The effect will be different due to different crops and varieties. Even the same crop and same variety will also have different effect under different climate and soil conditions. Before spraying the pesticide in large area, the small-scale test should be carried out so as to confirm appropriate regulator variety, concentration and dosage form, thus the pesticide can be used scientifically and reasonably.
Combine fine breed and various cultivation techniques
Plant growth regulator will only have effect on certain plant growth and development period, which is closely related with fine breed as well as cannot replace fertilizer, pesticide and other tillage measures. In order to achieve ideal effect on agricultural field, it should coordinate with other agrotechnical measures. For example, when spraying NAA or IAA on cuttings and stimulating rooting, it should keep certain temperature and humidity in the seedbed. Otherwise, it will be difficult to take root. Plant growth regulator is a kind of regulating substance in the biological body and cannot replace fertilizer. Even the regulators that can promote growth can only have effect under sufficient fertilizer conditions.