SummaryMeasurements of net NO3‐ influx have been made with excised bailey roots of differing salt status. With roots grown in 0.2 mM CaSO4, net NO3‐ influx shows partial saturation with external NO3‐ concentrations greater than 0.5 mM, and is greatly reduced in the absence of external K+ or Na+. Net NO3‐ influx from NaNO3 solution is as rapid as from KNO3 solution, but when both K+ and Na+ are present the roots show high specificity for K+ over Na+. When roots are high in Cl‐, net NO3‐ influx is greatly reduced, and the reciprocal effect of reduction in Cl‐ influx into roots high in NO3‐ is also found. There is some decrease in net NO3‐ influx and in Cl‐ influx when roots are high in organic anions, and under these conditions net NO3‐ influx is completely independent of cation influx. There is no effect of external Cl‐ (up to 10 mM) on net NO3‐ influx (1 mM solution), and very little or no effect of external NO3‐ on Cl‐ influx. The results are considered in relation to the hypothesis that influx of NO3‐ and Cl‐ is subject to feedback control from the internal NO3‐ plus Cl‐ content, but it is concluded that organic anions can also play an important part in controlling influx of NO3‐ and Cl‐. The interactions between cation and anion fluxes are discussed, and a unifying model for ion transport proposed.