Antioxidant enzyme activities and scavenger concentrations were determined in control Coker 312 callus tissue grown for 42 days on 0 NaCl and in callus tissue from a selected, salt-tolerant Coker 312 cell line grown for 42 days on media amended with 200 mM NaCl. While the cell line selected to grow on high salt media exhibited a 29% reduction in growth, a 96% reduction was observed in the control line when subcultured directly onto the 200 mM NaCl media. The salt-tolerant cell line grown at the 200 mM NaCl treatment exhibited significantly higher antioxidant enzyme activities than the control cell line grown on media without NaCl. Catalase activity was 300% higher; Peroxidase activity was 375% higher; GR activity was 395% higher; and AP activity was 431% higher. The higher catalase and peroxidase activities indicate that the salt-tolerant cell line has an increased ability to decompose H₂O₂. The higher AP and GR activities were reflected in the ascorbate and glutathione concentrations. The salt-tolerant cell line had a significantly lower reduced ascorbate/oxidized ascorbate ratio and a significantly higher reduced glutathione/oxidized glutathione ratio. These data indicate that the salt-tolerant cell line had a more active ascorbate-glutathione cycle and suggest that salt tolerance could,at least in part, be due to the cell's ability to up-regulate this cycle.