Sodium Sulfate Tolerance in Beta vulgaris (Sugar Beet) Callus Cultures

Beta vulgaris L. cv Prima Hill (sugar beet) callus, was selected for tolerance to Na2SO4 and maintained on this salt. The effect of 0, 70, 140, and 210 mM Na2SO4 on the concentrations of ions, reducing sugars, sucrose, quaternary ammonium compounds (QACs), and proline in unselected and selected callus was assessed. Both types responded similarly. Sodium accumulated in proportion to its initial concentration in the medium, while calculated molar concentrations of proline, reducing sugars, and sucrose increased slightly. There was a fourfold increase in the concentration of QACs. Tolerance, measured by survival and growth, was lost within one subculture in selected callus maintained without Na2SO4, although the high FW:DW ratio, characteristic of tolerance, was retained in the absence or presence of Na2SO4. Evidence suggests physiological adaptation to Na2SO4 occurred during selection.