Application technology of plant growth hormone

There are many ways to apply plant growth hormone, which vary with the kind of hormone and the purpose of use. Different methods of use, different effects, improper methods, and even harmful. Therefore, be careful before testing. For example, aerial roots of maize treated (daubed) with gibberellin occur earlier and more frequently than those sprayed with solution. When maize was irrigated with gibberellin solution, the plant was short and could produce more ears. The tillering was often inhibited by spraying or smearing with gibberellin solution, while the tillering was promoted by soaking seeds. At the same time, some methods are convenient to use, some are more troublesome, some are suitable for field experiments, and some are suitable for pot experiments. In short, flexible choices should be made according to actual needs.

Solution spraying: Solution spraying is a commonly used method in plant hormone applications. According to the purpose of application, leaves, fruits or whole plants can be sprayed evenly, and the amount of solution should be wet to the spraying position. It is generally suitable for evening or morning dew when it is dry, and it is not suitable for spraying before rain or under the scorching sun. Depending on the duration of the effect and the need, one or more sprays can be applied.

2, solution drop: This method is mostly used to deal with plant stem top growth points, flowers or dormant buds. Dropping auxin or gibberellin solution on the growing point of stem promoted the elongation of apical tissue more obviously than spraying method. This method can be used quantitatively, the dosage is more accurate, suitable for scientific research, in production is also used for the propagation and cultivation of some precious trees and ornamental plants.

3, solution soaking: This is the earliest method applied to woody plant cuttage propagation. For indoleacetic acid, naphthylacetic acid soaking cuttings to promote rooting. During treatment, the hormone solution with a certain concentration is poured into the container at a depth of about 1.6 cm, and then the morphological lower end of the cuttings is soaked in the solution for a certain time, and the cuttings are taken out in the sand table to promote rooting. Solution immersion is divided into slow immersion and fast immersion. The slow dip method uses a low concentration aqueous solution (10-100ppm) for 12-24 hours and then removes the cuttings. The rapid soaking method uses 50% alcohol solution with high concentration (more than 1000ppm), and the cuttings can be taken out after 5 minutes of treatment, and the cuttings can be taken out after the alcohol volatilizes. The application of rapid immersion method is more convenient than slow immersion method, and the absorbed dose is more uniform. At the same time, it can avoid the disadvantage that the chemical absorption of cuttings is affected by the evaporation of water in leaves and the change of temperature, humidity and other conditions during slow soaking. In addition, it is also commonly used to soak fruit and seed, including seeds and seed potatoes. For example, tomatoes and other fruits are ripened by dipping them in an aqueous solution of ethephon. Soak soybeans and mung beans in gibberellin solution to promote bean sprouts growth. Seed soaking with chlormequat to increase wheat tillers. Soaking potato tubers with gibberellin breaks dormancy of summer harvest potatoes.

4, solution smear: This method is used for a certain organ of the plant such as leaves, buds, stems and branches of the incision, etc., to observe some physiological effects of a hormone on the plant. For example, a cytokinin solution applied to one side of a leaf has been observed to delay leaf senescence. The duration of solution application is short, so it is not suitable for field application.

5. Solution irrigation: This method is to apply the solution to the soil or mix it with fertilizer and soil. Hormonal soil treatment was first applied to vegetable crops and later extended to cereal crops. Some growth inhibitors, such as chlormequat, Formica-D, and AMO-1618, are very effective when used in solution irrigation or mixed with soil. However, the growth inhibitor B9 is toxic when poured into the soil in solution. B9 is not suitable for this purpose. The effect of solution irrigation is closely related to soil texture. Chlormequat, for example, works best in loam soil, and in clay or sandy soil by solution spraying.

6, solution culture: in the plant culture solution, add a certain concentration of plant hormones, germinated seeds or seedlings into the culture solution, so that the roots absorb nutrients and hormones at the same time. This method can be used to study the physiological effects of plant hormones on roots and shoots. It is similar to the method of solution irrigation, but the solution culture method can control the dosage of hormones very accurately and is convenient to observe. It is a means of studying the physiological effects of plant hormones.

7, solution injection: mostly used for woody plants, the practice is to drill a small hole in the fruit trunk, the hole depth is 1/3-1/2 of the trunk diameter. Then the prepared hormone water agent is put into a container, one end of the container is connected with a thin rubber tube, and a small section of thin glass tube is inserted into the nozzle of the container. The nozzle is plugged with small pieces of foam plastic to adjust the dripping speed, so that the water drips slowly in drops, and then the glass tube is inserted into the drilled hole and absorbed by the fruit tree trunk. When injecting fruit tree root, selecting root with thickness similar to rubber tube, cutting, peeling off a section of cortex, inserting the broken root xylem into rubber tube connected with container filled with plant hormone aqueous solution, and absorbing by root xylem section.

8, oil coating: This method is similar to the solution coating, but it has more advantages. Some plant stems, culms and leaves have waxy or velutinous surfaces, round and smooth fruits, such as solution treatment, liquid medicine is easy to lose. Oil coating, easy to adhere, easy to absorb, and the drug solution lasts a long time, generally one treatment can be. Where the plant is locally treated, the effect on the local area is obvious, but the applied agent can also be transported to other parts of the plant after being absorbed locally, and the overall effect on the plant occurs.

9. Powder irrigation and spraying

① Powder dipping irrigation is a method used in large-scale cuttage propagation of woody plants. Compared with the solution soaking method, it has the advantages of shorter treatment time and longer drug maintenance time. The concentration of the powder varies with different cutting types, and the concentration of naphthylacetic acid powder used by woody plants is 500-2000ppm. For some woody plants that are difficult to root, higher concentrations (5000-12000ppm) are required to promote rooting of cuttings. For herbaceous cuttings, the concentration of naphthylacetic acid powder can be appropriately reduced. When treating, the lower end of the cuttings is soaked in water and then dipped in the powder. The cut is covered with the powder. In order to prevent the powder attached to the lower end of the cuttings from falling off when cutting in the seedbed, a small groove can be opened on the seedbed first, and the cuttings treated with powder are placed obliquely in each groove, and then covered with soil and compacted in the groove.

② Powder spraying can be carried out by sprayer, and it can also be sprayed by aircraft when it is applied on a large scale. The powder dosage is large, and the solution spraying can also achieve the same purpose as powder spraying. Therefore, it is used less in production.

In addition, attention should also be paid to the validity period of the medicament, such as some regulators are more stable in nature, conducive to transportation and long-term storage, such as yield-increasing spirit. However, some regulators have a limited shelf life at room temperature. If gibberellin is valid for two years, it should not be stored for too long. Some of the original powder of the regulator can be stored for a long time, but when prepared into an aqueous solution, it is easy to deteriorate, such as ethephon prepared into an aqueous solution, to be used in time, the lower the concentration, the faster the failure. Gibberellin diluted solution, even if placed in the refrigerator, but also can only be stored for a short period of time (valid only about a week).