EFFECT OF THE CYTOSKELETON MODIFIERS ON THE WATER-HOLDING CAPACITY OFWINTER-WHEAT TISSUES

Effects of the inhibitors of the cytoskeletal framework, 10 mu M cytoc halasin and 1 mM colchicine, on the tissue water-holding capacity (WHC ) in winter wheat (Triticum aestivum L.) seedlings were studied. WHC w as defined as the amount of water that could not be extracted by 20% p olyethylene glycol (PEG-6000). The inhibitors decreased WHC. Severe wa ter stress (30% PEG) and the membranetropic compound pipolphene both f urther augmented the effects of cytochalasin and colchicine. A low con centration (5 mu M) of exogenous calcium prevented and a high concentr ation (1 mM) enhanced the inhibitor action. A relationship between WHC and the integrity of the cytoskeleton components was proposed, and WH C dependence on the cellular Ca2+ concentration was shown. Destructive changes in the cytoskeletal framework result in the reduction of the total water-holding surfaces of the cytoskeletal filaments and associa ted macromolecules and, as a consequence, in changes of the cellular w ater state and a decrease in tissue WHC.