Tsitokininy. Interaction tsitokinina with auksinom

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At presence auksina tsitokininy are extremely active at indutsirovanii divisions of vegetative cages in culture of fabrics. Sometimes they stimulate also development of kidneys in formed kalluse. The differentiation in culture of fabrics depends mainly on relative concentration present rostovyh substances. High moljarnoe the relation tsitokinina to auksinu leads to a gemmation. If concentration tsitokinina and auksina are approximately equal, growth not differentiated kallusa is stimulated. At the high relation auksina to kinetinu the tendency to initsiatsii growth of roots is observed.

In typical systems with a cellular stretching, such as koleoptil oats and epikotil peas, kinetin usually ingibiruet stimulirovannyj auksinom longitudinal growth also stimulates the cross-section.

Interaction Detection kinetina with auksinom has demanded regular studying of other physiological systems, such, as apikalnoe domination which, as it is known, influences auksin. It has been thus established that local drawing kinetina on the subjected to repression kidneys eliminates inhibition and causes growth of these kidneys.

Also It has been shown that the inhibition of growth of lateral kidneys auksinom is actually caused by a formation induction in them etilena (see gl. 10). At the same time entering tsitokinina ingibiruet synthesis etilena. Expansion of young leaves also is stimulated tsitokininami.

At adult plants synthesis tsitokininov occurs mainly in root system, whence they on ksileme are transported in an elevated part of a plant. The more low on a stalk lateral kidneys, the further they from a source auksina, being in apekse a stalk, and the more close to a source tsitokininov in roots are located. As apeks a plant showing apikalnoe domination, in the course of growth leaves from lateral kidneys, the last start to be dismissed because tsitokinin overcomes influence auksina. Antagonism auksina and tsitokinina formation ' vedminoj brooms ' owing to full elimination of normal suppression of growth of the based kidneys separated from apeksa only several short mezhdouzlijami speaks also. In the nature it occurs when a mushroom inducing formation ' vedminoj of a broom ', gets into a plant and develops substances with activity, characteristic for tsitokininov.

Action tsitokininov underlies other phenomenon over which long broke heads physiologists of plants. Often it was necessary to observe that if from a plant, for example tobacco to remove leaves the fiber maintenance in them quickly decreases, and the maintenance of soluble nitrogen increases. It was supposed that this massed destruction of fiber at least the short period of a life of many cut off plants and their parts, especially leaves partially speaks. Casually it was revealed that addition kinetina in a nutritious solution in which are shipped chereshki the leaves which have been cut off from plant Xanthium, leads to longer preservation of green colour of leaves. Thus, tsitokini th detain ageing. Subsequently it has been shown that the given effect is caused by that tsitokininy promote maintenance of certain levels of fiber and nucleinic acid, possibly, by decrease in speed of their disintegration, and also as a result of preservation of integrity of a cellular membrane. It has been noticed that drawing tsitokinina on leaves intaktnyh plants too detains their ageing (fig. 9.31). Possibly, tsitokinin should contain constantly in the water arriving from roots to leaves to interfere with ageing of the last.