Sodium Fluxes in ExcisedCitursRoots under Steady-State Conditions, with Particular Reference to Salinity Resistance

Sodium influx and efflux rates from excised Citrus roots were studied. The sodium fluxes in the free spaces of the roots of the salt-sensitive variety Sweet Lime and of the salt-resistant variety Cleopatra Mandarin were very close to each other. On the other hand, the sodium fluxes from intracellular spaces were considerably lower in the roots of variety Cleopatra Mandarin. The experimental findings were evaluated by compartmental analysis and the rate constants of the sodium fluxes calculated. The possible significance of these procedures for the study of salt resistance is indicated.