Transpiratsija. Regulation of movements of closing cages ustits

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For a long time it is known that the width ustichnyh cracks (otverstost ustits) is defined turgorom closing cages ustits about what it was already told in gl. 2.

However only recently, last decade, it was found out that tourist's mountains of these cages depends mainly on the maintenance of salts kalija. At night concentration of the dissolved substances in vakuoljah closing cages is rather low; according to it fp it is great, cages are languid and ustichnaja the crack is closed. At a dawn from the next cages in vakuoli closing cages ions kalija start to arrive. This process is often accompanied by disintegration of starch and accumulation of apple acid. As a result fp absorption the waters closing cages, having very elastic, non-uniformly utolshchennye walls sharply decreases, begins, bulk up and are bent thus in such a manner that ustichnaja the crack opens. The exit of ions To + from closing cages in the end of day or at a water lack conducts to reduction of volume of closing cages therefore ustitsa are closed (fig. 6.14). Nearby ustichnye cages epidermisa serve as the tank, in the motor ions To + remain, while ustitsa are closed. Any change of these sizes okoloustichnyh cages always opposite on a sign also promotes simultaneous change in closing cages either opening, or closing ustits.

When through a cellular membrane pass any positively charged ions, for example ions To +, the cage electroneutrality remains thanks to simultaneous moving of other charged particles: or negatively charged aniony move in the same direction, as To +, or ions N + should move in an opposite direction (see gl. 7). Now it is known that at some plants the important role in regulation the tourist's mountain of closing cages plays movement of ions of chlorine (С1 _), at other plants any other mechanism operates, apparently. At corn (Zeamays) about 40% of ions To + enters into closing cages or leaves them accompanied by ions С1-. There are plants at which participation of ions С1- is rather insignificant also their function can carry out any other ions. similar replacement is observed sometimes and at those plants at which in norm this role is played by ions С1-. Intensive moving of ions N + through membranes of closing cages in a direction opposite to movement of ions To +, is characteristic, apparently, for all plants. Really, opening ustits is accompanied by appreciable increase endocellular rn that, certainly, and should be expected when ions N + leave a cage. Organic acids as at opening ustits their maintenance in vakuoljarnom juice increases can quite be source of ions N + present in vakuoljarnom juice.