Аннотация:Ion-exchange properties of the polymeric matrix of cell walls isolated from roots of 20-day-old Cicer arietinum L. plants grown in nutrient solution in the presence of 0.5 and 80 mM NaCl were studied by potentiometric method. The ion exchange capacity (Si) and the swelling coefficient (Kcw) of root cell walls were estimated at various pH values (from 2 to 12) and at different means of solution ion strength (between 10 and 250 mM). To analyse polysigmoid titration curves pHi = f (Si), Gregor’s equation was used. It was shown that Gregor’s model fits quite well the experimental data. The total quantities of cation exchange (Stcat) and anion exchange (Stan) groups were determined in the root cell walls. It was found that in the plant root cell walls, there are 3 cation-exchange groups (two types of carboxyl groups and phenolic group) and one anion-exchange group (amine group). The quantity of functional groups of each type (Sj) was estimated, and the corresponding values of pKaj were calculated. It was shown that for carboxyl groups of polygalacturinic acid arranged in cell wall structure the acid properties are enhanced by the increasing of electrolyte concentration. It was found that swelling of root cell walls changes with pH and NaCl concentration in the solution. The findings are discussed from the standpoint of involvement of the root cell walls in plant response to salinity.