Abstsizovaja stress acid-hormone. Opening abstsizovoj acids

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The Experiences spent by different researchers, have shown that keeping of leaves at a short bottom leads to formation of wintering kidneys. It became clear that any hormonal signal is involved in this process. By consecutive clearing of extracts from a birch (Betula) and their analysis by means of biotests for a condition of rest of P.F.Uering and its employees (Aberystwith, Wales) have found out some connections inducing rest. The substance making the greatest effect in this respect, is called now abstsizovoj as acid (ABK; fig. 10.10). Such name has been given it because approximately at the same time F.T.Addikott and its employees in California have established that subsidence is connected with this substance (abscission) cotton boxes. In general ABK, apparently, is of little importance in subsidence of leaves so this name not absolutely approaches for the given substance.

For a number of years role AVK in stimulation of rest of trees was a polemic subject. Entering ABK detains blooming of kidneys if rest has been interrupted by low temperatures.

However if to define maintenance ABK in trees throughout the whole season or under various conditions of growth high levels ABK not always correlate with rest and on the contrary. For example, it has been established that at an apple-tree maintenance ABK in actively growing tops of runaways above, than in the based. at the same time at plum and at grapes as have shown analyses, the maximum maintenance ABK coincides with the maximum depth of winter rest. These, apparently, inconsistent results, possibly, it is possible to explain by means of the concept of hormonal balance, i.e. By quantity definition ingibirujushchej ABK in relation to hormones stimulating growth - gibberellinam and tsitokininam. So, at a maple (Acer) greatest quantity ABK contains in young runaways, whereas level giberellina below all at a short bottom. ABK, present at runaways, possibly, induces rest in the conditions of short, instead of long day when high levels gibberellina can overcome the effects caused ABK.

We do not know, how the genetic control of summer rest is carried out. At one trees those leaves which are in earlier generated kidneys then new kidneys are put are developed only; at other trees formation of leaves stops only in the middle of summer. Conditions of environment as, for example, water stress, certainly promote summer rest, about possibilities of the hormonal control we know very little. At a willow (Salix) maintenance ABK sharply increases in July, directly ahead of the growth termination. However at other kinds of any accurate law it has not been in this respect noted. Winter rest usually interrupts, if within several weeks of temperature exceed temperature of freezing of water a little. It is supposed that this period is connected with destruction ABK. But when measure the general maintenance ABK, often do not find any difference between control and skilled plants. It is possible to explain action of the cold period more likely to that during its increasing quantities ABK gradually turn in gljukozid abstsizovoj acids. It can be way of isolation or inaktivatsii ABK. At interruption of rest the maintenance of the various substances activating this process, also increases. They, apparently, will neutralise action present at plant ABK (fig. 10.12).

Therefore the given condition of a kidney can be considered as result of the reached balance between activating hormones and ABK. Last usually functions only when the maintenance of activating hormones, such as gibberellin, decreases under the influence of short day.

The Hormones interrupting rest, obviously, are synthesised, and ABK collapses directly in fabrics of the kidney. Thus, if to influence by a cold to subject only some kidneys on a tree they at transferring in warmly start to grow, whereas other, not sustained on a cold, kidneys continue to remain at rest. It makes it clear that interruption of rest unlike its beginning is not supervised by the hormones moving on a plant.