Sodium fluxes in corn roots: comparison to Cl and K fluxes, and to Na‐fluxes in barley

Carbonylcyanide, m‐chlorophenyl hydra‐zone (CCCP) decreased the ATP content of barley and corn roots by 80% within 5 min. The protonophore inhibited K and Cl absorption by largely unvacuolated root tips, and vacuolated root segments of barley and corn. The protonophore also inhibited Na absorption by root segments and Na extrusion by root tips of barley; it did not affect these Na fluxes in corn root tips and segments, and Na Influx in barley root tips. It was concluded that corn roots lack a metabolic mechanism for Na extrusion from the cytoplasm to the external solution or vacuole, which is functional in barley roots.