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l h e effects of NaCl on the transport rates of cations, NO3-, and reduced N compounds between roots and shoot and on NOsassimilation rate were examined on plants of two species differing in their sensitivity to salinity, bean (Phaseolus vulgare 1 . cv Cabriella) and cotton (Gossypium hirsutum l. cv Akala). Biomass production after 20 d in response to 50 and 100 mM NaCl decreased by 48 and 59% in bean, but only 6 and 14% in cotton. The comparison of the flow patterns obtained for control and NaCIfed plants showed that salinity induced a general decrease in all the fluxes involved in partitioning of N and the various ions. This decrease was markedly higher in bean than in cotton. Within either species, the different flows (uptake, xylem flux, phloem flux) of a given element were affected by NaCl to the same extent with minor exceptions. No specific effect of salinity on any of the components of N partitioning were discerned. The greater sensitivity of nitrate reductase activity to NaCl in bean leaves compared to cotton leaves seems to be due to a decreased compartmentalization of ions rather than to a difference in salt tolerance of the enzyme itself. Overall, our data show that alteration of mineral nutrition is not solely the reflection of a decreased growth rate, but also is a general process that impairs uptake of all the minerals even at mild NaCl salinity. '