Fig. 1. Cumulative net NO^-₃ uptake by roots of Pima (left panel) and Acala (right panel) cotton grown in 0.01 (A, D), 0.10 (B, E) or 1.00 (C, F) mM NO^-₃ for 3 d, and then exposed to uptake solutions. Cumulative Net NO^-₃ uptake was measured by following the depletion of NO^-₃ from uptake solutions initially containing 0.1 mM NO^-₃ ± 1 or 10 mM NH⁺₄. See Table 1 for root NO^-₃ concentrations.