X-ray microanalysis of ion distribution within root cortical cells of the halophyte Suaeda maritima (L.) Dum

The ion content of compartments within cortical cells of mature roots of the halophyte Suaeda maritima grown at 200 mol·m(-3) NaCl has been studied by X-ray microanalysis of freeze-substituted thin sections. Sodium and Cl were found in the vacuoles at about four-times the concentration in the cytoplasm or cell walls, whereas K was more concentrated in the cell walls and cytoplasm than in vacuoles. The vacuolar Na concentration was 12- to 13-times higher than that of K. The Na concentration of cell walls of cortical cells was about 95 mol·m(-3) of analysed volume. The cytoplasmic K concentration within the mature cortical cells was estimated to be 55 mol·m(-3) of analysed volume.