Electrical conductivity of differently treated isolated cuticular membranes by impedance spectroscopy.

A comparative study of the electrical properties of isolated tomato cuticles (native, Na+, and Ca2+ forms) in contact with different NaCl solutions has been performed by impedance spectroscopy measurements. In all cases, equivalent circuits consisting of a parallel combination of a constant phase element and a resistance were found, and variation with NaCl concentration of both parameters has been considered. From the electrical parameters, the cuticle conductivities and equivalent capacities were determined, and a comparison between conductivity values at C = 0 (without electrolyte contribution) and those obtained with dry membranes is also made. Differences in conductivity and capacity values for the three cuticles are explained by some changes in the structure and electrical interactions.