Research on the induction of antioxidant enzyme activity in cotton transferred callus tissue from a control and a sodium chloride tolerant cell line to culture tubes that were sodium chloride-free; amended with sodium chloride; or amended with sodium chloride, abscisic acid, hydrogen peroxide, or xanthine and xanthine oxidase. harvesting of callus tissue occurred at 30 minutes, 1 hour, 2 hours, 4 hous, and 8 hours, and the experiment analyzed these samples for antioxidant activity. The sodium chloride acclimated callus initiated an upregulation of antioxidant acitivity prior to the control callus. Sodium chloride, abscisic acid, hydrogen peroxide, and oxygen initiated upregulation of superoxide dismutase, ascorbate peroxidase, glutathione reductase, and peroxidase in the sodium chloride tolerant cell line. The increases that resulted from abscisic acid and oxygen either closely matched or preceded the increases that occurred with the sodium chloride treatment. 29 refs.