Figure 5. ABA enhances the generation of superoxide. Epidermal strips were incubated in the opening medium containing 10 µM CaCl2 for 2 h in the dark. They were transferred to the medium containing 10 mM MES-KOH, pH 6.15, 50 mM KCl, 110 µM CaCl2, 100 µM ethylenediaminetetraacetic acid (EDTA) and 1 mM epinephrine, or the medium containing 10 µM ABA. The activities were measured spectrophotometrically at 480 nm. ○, 0 µM ABA; ●, 10 µM ABA. Bars represent standard errors of means.