Active sodium and potassium transport in cells of barley roots.

Abstract
There is evidence to support a potassium influx pump and a sodium efflux pump in barley root cells. These pumps are not inhibited by ouabain, as are animal sodium and potassium pumps. The estimates of fluxes in these cells show that selectivity for potassium is set up at the plasmalemma so that it would be reasonable to locate these pumps at this boundary of the cytoplasm. These pumps could well be equivalent to "mechanism 1" of Epstein et al. for which a location at the cytoplasm has also been suggested.