The activity of the enzyme nitrate reductase was studied in cotton plants (Gossypium hirsutum, L), cvs IAC 20 e IAC 13-1, subjected to increasing water deficits, and after turgescence recovery. The physiological activity of the leaves, represented by the activity of the enzyme, was decreased for water potentials bellow -1.5 MPa. Cultivars were not statistically different. Nitrate reductase activity was a very sensitive method to evaluate the effects of water stress on plant growth, being an indicative of plant metabolism.
Gossypium hirsutum; total water potential
