Tsitokininy. As operate tsitokininy

you are: Tsitokininy

In absence tsitokinina DNA synthesis proceeds until in a cage is available auksin, but cages thus do not share. tsitokinin it is required for some process occurring after end replikatsii DNA, but prior to the beginning of the present mitosis. Formation of fibers necessary for cellular division, possibly, what are connected with mitoticheskim the device can be this process. Really, after addition tsitokininov occurrence of various fibers is observed, and it occurs even then when synthesis new mrnk is blocked by Ingibitorami. Therefore it is quite probable that tsitokininy supervise translation preformed mrnk which products concern some aspects of cellular division.

Other key to the mechanism, functioning tsitokininov can lie in their structure. tsitokininy are related to components of nucleinic acids. Actually tsitokinin it is possible to find out as one of the bases close antikodonom in molecules several trnk, and in this position it, possibly, participates in linkage trnk with ribosomes in the course of fiber synthesis (fig. 2.11 see). However from this go it is impossible to understand, how tsitokininy function as hormones as after drawing on a vegetative fabric they do not join as those in trnk More likely, they are split to adenina which after inclusion in polinukleotidnuju the chain is modified by joining of a lateral chain - izopentenila. Nevertheless structural similarity tsitokininov with components of nucleinic acids, and also character of their action on a plant testify that tsitokininy, probably, play any role in fiber synthesis. Really, molecules tsitokinina unsteadily contact ribosomes - little bodies on which in a cage fibers are synthesised. As a communication place the fiber actually serves, which itself is connected to ribosomes. tsitokinin and connecting fiber can be a factor part initsiatsii, specific fiber participating in synthesis on ribosomes. Whether supervise tsitokininy such way cellular division, and it is possible, and other aspects of a cellular metabolism, remains while to unknown persons.

The same as and in case of other hormones, functioning tsitokinina is carried out, possibly, different ways leading to various effects. We will consider, for example, how tsitokinin prevents ageing of leaves. At presence tsitokinina fiber levels in leaves above, than in its absence. in this case tsitokinin does not accelerate fiber synthesis, and ingibiruet its splitting. As it was already mentioned, it has been shown that tsitokinin supports integrity of cellular membranes. As it carries out these functions, now it is not known. But the mechanism becomes clear when we learn more about functioning of hormones at molecular level.