In addition to water and minerals absorbed from the soil, and produced in the process of photosynthesis of carbohydrates needed for energy and growth, the plant cell for optimal growth requires more and in some other chemicals. In recent years several phytohormones able to synthesize, and now they are used in agricultural production. Their use, in particular, to control weeds and to obtain seedless fruit. Plant hormones coordinate the growth of plants. Particularly clearly this ability hormones regulate the growth seen in experiments with cultures of plant tissues. If we separate from the plant alive cells that retain the ability to share, in the presence of essential nutrients and hormones, they begin to grow actively. But if the right balance of different hormones will not be exactly satisfied, then the growth will be uncontrollable and we have cell mass, resembling the tumor tissue, ie, completely devoid of the ability to differentiate and form structures. At the same time, appropriately changing the ratio and hormone concentrations, the experimenter can grow from a single cell whole plant with roots, stems and all other bodies.
Main classes rasteniyAuksinyVeschestva stimulating cell expansion plants, collectively known as "auxins. Deposited on the cut stem, auxins catalyze the formation of roots from cuttings. However, excessively high doses, they inhibit root formation. General sensitivity to acting only with badly at root tissue is significantly higher than that of tissues of the stem, so that the dose of these hormones, the most favorable for the growth of stem, root formation is usually slow.