Plasmalemma transport of OH- in Chara corallina: dynamics of activation and deactivation.
The light-mediated, time-dependent rise in the pH value at the center of an alkaline band was analyzed using the methods of numerical analysis. From this analysis an expression of the time-dependent build-up of OH- efflux was obtained for these bands. This information can now be employed to determine whether the light-activated transport of OH- and HCO3- influences the electrical properties of the plasmalemma. The dark-induced deactivation of OH- transport was also characterized, revealing a transition from efflux to a transient influx phase during deactivation. Numerical analysis of the steady-state OH- diffusion pattern, established along the surface of an alkaline band, revealed that the OH- efflux width was wider than previously envisaged. It was also found the OH- sink regions exist on either side of the efflux zone. These, and other characteristics revealed by the numerical analysis, enabled us to extend the OH- transport model proposed by Lucas (J. Exp. Bot. 1975, 26:347).
D001693:Biological Transport, Active; D002462:Cell Membrane / Q000378:metabolism; D003624:Darkness; D004058:Diffusion; D056890:Eukaryota / Q000378:metabolism* / Q000648:ultrastructure; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000378:metabolism*; D007700:Kinetics
D006878:Hydroxides