A diffusion approach to the electrolyte leakagefrom plant tissues

The exchange of ions between plant tissues and the external solution in vitro exhibits prominent biphasic kinetics. This is generally ascribed to the different contribution of the two compartments – apoplast and symplast – involved in the process. In this regard, an electro-diffusion model of the leakage is proposed in the paper. On the basis of the balance of fluxes through the plasmalemma and the cell wall, a system of differential equations describing the ion concentration in the outer solution is found. For a wide range of the system's coefficients, its behaviour is well approximated by a previously obtained analytical function. The values of the function's parameters, derived from the fit with experimental data, correlate adequately with the water deficit conditions of the samples. Hence, these parameters may be used to characterize the physiological status of the investigated plants.