Increase in electrogenic membrane potential with washing of corn root tissue.

Washing of corn root tissue increases the electrical potential difference, negative inside, across the membranes of epidermal cells. There is no lag period in the development of the extra potential, and the entire increase is electrogenic as evidenced by collapse with the uncoupler, (p-trifluoromethoxy)-carbonyl cyanide-phenylhydrazone.Proton extrusion by the tissue declines with washing but can be reinstituted by the addition of mersalyl, an inhibitor of the Pi-OH(-) antiporter of mitochondrial membranes.It appears that washing may enhance or augment the activity of an electrogenic ion pump, possibly a proton or cation efflux pump. In addition, there may be augmentation of an anion-OH(-) antiporter driven by the proton motive force created.