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The article discusses an improvement of a previously developed method for assessment of ion leakage from plant tissues as a gauge of membrane and cell wall performance under stressful environment. It employs conductometric measurements of the ion efflux from leaves and their quantitative interpretation by a theoretical model based on the laws of diffusion. Experimental data are readily fit with the model and results are in accordance with relative water content of dehydrated barley (Hordeum vulgare) seedlings of two distinct cultivars. Some new parameters obtained from fitting are proposed as reliable indicators of the leaf status. They appear to be helpful in further distinguishing the behavior of two separate cellular structures with respect to their electrolyte permeability. It is concluded that the established method based on the kinetics of ion leakage is adequate for evaluation of contrasting genotypes under normal and stress conditions. Furthermore, it could be used as a simple and powerful tool for routine analysis and screening for drought tolerance in crops. [ABSTRACT FROM AUTHOR]

The employment of manganese (Mn2+) as a mediator for the electron transfer across glassy carbon-supported thin lecithin films in contact with electrolyte is described in the present work. The results suggest, that the ascorbate oxidation, which is normally hampered by the film, can proceed through the incorporated manganese. In this respect, the potential of Mn for modification of lipid wetting films in construction of sensitive interfaces is briefly outlined. [Copyright &y& Elsevier]