Detailed invesigations of the activity of antioxidant enzymes in salt stressed cotton plants and cotton callus tissue has focussed attention on the possible role of these enzymes in the salt tolerance properties of non-halophytic plants. Glutathione reductase and peroxidase have been shown to undergo considerable increases in activty when cotton plants or cotton callus are exposed to high concentrations of salt. In order to further examine the correlation of antioxidant enzyme activity with salt stress we have begun the construction of Agrobacterium-mediated transformation vectors containing glutathione reductase cDNA in sense and antisense orientations. Cotton tissue transformed with these constructs are expected to show differential accumulations of glutathine reductase in response to salt stress which may, in turn, have an effect on the salt tolerance characteristics of the transformed tissue.