Heteroauxin

It was first isolated in 1934 from the culture of molds and other microorganisms by the Dutch chemist F. Kögl and colleagues; later found in higher plants; it is formed from the amino acid tryptophan in the leaves , and then moves to the growing stems and roots of plants, where it is oxidized and goes into an active state.

Heteroauxin can be synthetically synthesized by reacting indole and glycolic acid in the presence of a base under the influence of high temperature: ^[1]

It can also be obtained by hydrolysis of indolyl-3-acetonitrile (which, in turn, can be obtained by the interaction of gramine with alkali metal cyanides ), the Fischer synthesis of indoles, the reaction of indole with diazoacetate , oxidation of indolyl-3-pyruvic acid and other methods. ^[one]

The comparative simplicity of its synthesis contributed to the study of the action of heteroauxin on the plant organism, as well as to its use in crop production, for example, to accelerate root formation during propagation of plants by cuttings (often used in combination with vitamins C and group B). Depending on the type and degree of lignification of the cuttings, the doses of heteroauxin range from 50 to 200 mg / l.

The physiological role of heteroauxin in plants is so diverse that it is still not clarified in detail.

In addition to stimulating the extension of plant cells, heteroauxin also affects many other processes. Under its action, cell division is intensified. It is known that the process of leaf decay is controlled by heteroauxin: before falling, its inflow from the leaf into the petiole is greatly reduced. Treatment of the petiole with heteroauxin prevents falling. Particularly complex are the mechanisms of heteroauxin regulation of flowering and fruiting processes. It affects the floor of the resulting flower, the growth and formation of the pollen tube. It was also established that fruit growth is stimulated by heteroauxin, which is formed in the seeds and enters the fetal tissue from there. If the seeds are removed, the growth of the fetus stops, however, it will resume again after the fruit tissue begins to receive heteroauxin artificially.

Some effects of gibberellins are mediated through their stimulation of the formation of heteroauxin.

Modern ideas about the organization of the heteroauxin receptor systems, the nature of the processes initiated in the plant cell by its interaction with these receptors are rather limited.

Hetero-auxin, which stimulates plant growth in small concentrations, appears to be its inhibitor in large concentrations ^[2] .

1. ↑ ^{1 2} Herbert E. Johnson and Donald G. Crosby (1973), Indole-3-acetic Acid, Org. Synth .; Coll. Vol. 5: 654
2. ↑ Galaktionov S.G. Biologically active. Publishing house "Young Guard", a series of "Eureka", 1988.