[Membrane regulation of water homeostasis of Nitella flexilis]
2008
Plaks, A.V., National Academy of Sciences, Minsk (Belarus). The V.F. Kuprevich Institute of Experimental Botany
Investigation of role of plasmalemma and vacuolar cells in the support of cytosol homeostasis of charophyte Nitella flexilis was realized with the help of pressure probe method. Proton and stress permeability of tonoplast was evaluated with the help of electrophysiological methods with varying pH of vacuolar solution in the range of pH 5 - 8. The passive proton permeability of the tonoplast of Nitella cells was evaluated. Research results showed that the ratio of permeability coefficients for H+ and water molecules for the vacuolar membrane were very low and showed the rate of PH/Pf0.001. It was shown that high H2O2/H+ selectivity of aquaporines was vital for the conservation of pH - gradient on the tonoplast, which was used by plant cells for the osmoregulation. The tonoplast modification under stress conditions and the possibility of participation of lipid pores and ion channels in the maintenance of water homeostasis were studied. Regulation mechanisms of water homeostasis in course of turgor pressure change were investigated. Models of aquaporin selectivity and homeostasis regulation of the cell were discussed
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