What Is Somatotropin?
Auxin is a type of endogenous hormone containing an unsaturated aromatic ring and an acetic acid side chain. It is abbreviated as IAA in English. Its chemical nature is indoleacetic acid. In addition, 4-chloro-IAA, 5-hydroxy-IAA, naphthaleneacetic acid (NAA), indolebutyric acid, and the like are auxin-like substances.
- Auxin
- 1880
- The most obvious effect of auxin is to promote growth, but the promotion of stem, bud, and root growth varies with concentration. The optimum concentration of the three is stem> bud> root, which are about 10E-5 per liter, respectively.
Auxin analogs
- With the study of plant hormones, people are also continuously using artificial methods to make some analogs with plant hormone activity. These plant hormone analogs are commonly called plant growth regulators. There are many types of plant growth regulators. According to different functions, plant growth regulators can be divided into plant growth promoters (such as naphthaleneacetic acid, 2,4-D, etc.), plant growth inhibitors (such as triiodobenzoic acid, chlorophyll, etc.) and Three types of plant growth retarders (such as brazil, PP333, etc.). The following briefly introduces their functions and applications.
- Indole butyric acid: Indole butyric acid is abbreviated as IBA. The pure product is white or slightly yellow crystals with a slight odor. It is insoluble in water and can be dissolved in organic solvents such as ethanol and acetone. When in use, it can be dissolved in a small amount of alcohol first, and then diluted with water to the required concentration. It is mainly used to promote the cutting rooting of plants, and especially has obvious effects on rooting. However, the roots induced by indolebutyric acid are thin and long, and the roots induced by naphthalic acid are relatively thick. Therefore, these two plant growth regulators are often mixed for use in production.
- Triiodobenzoic acid: Triiodobenzoic acid is referred to as TIBA. The pure product is a white powder. It is insoluble in water and soluble in organic solvents such as ethanol and ether. Triiodobenzoic acid can hinder the transportation of auxin in the plant, inhibit the growth of the top of the stem, promote the germination of lateral buds, thereby dwarf the plant, increase the number of branches, and increase the number of flowering and fruiting. Triiodobenzoic acid has been widely used in soybean production. Spraying soybean plants with its solution can shorten the plant, increase the number of branches and increase the rate of pod formation, thereby increasing soybean yield.
- Chitin: Abbreviated as CCC, the chemical name is 2-chloroethyltrimethylammonium chloride. Pure product is white crystals, easily soluble in water. Its effect is opposite to gibberellin, which can inhibit cell elongation, but does not inhibit cell division, so it can make plants shorter and thicker. Chitosan has obvious effects on preventing rice and wheat lodging, preventing cotton buds and bolls from falling off and increasing yield. Since chlormequat is not easy to be fixed by the soil and is not easily broken down by microorganisms in the soil, it is better to apply it directly to the soil.
- PP333: PP333 is referred to as PP333. PP333 can inhibit gibberellin biosynthesis, slow down the division and elongation of plant cells, and inhibit stem elongation. Paclobutrazol is widely used in fruit trees, flowers, vegetables and field crops, with significant effects. For example, spraying Paclobutrazol on tomato seedlings can make the seedlings shorter and more branchy. China's food pesticide residue standard GB 2763-2005 stipulates that the Paclobutrazol Limit Limit (MRL) in grains is 0.50 mg / kg.
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