Figure 3.

Photosynthetic inhibitors eliminated abscisic acid (ABA)‐induced generation of reactive oxygen species. (a) Effect of DCMU and light on ABA‐induced generation of reactive oxygen species in Arabidopsis guard cells. (b) Effect of DBMIB on ABA‐induced generation of reactive oxygen species in Arabidopsis guard cells. Epidermal strips containing preopened guard cells were pretreated with 10 μM DCMU or 0.2 μM DBMIB for 20 min and then incubated with 10 μM ABA for 5 min. Experiments were conducted at 23°C in the light (50 μmol m⁻² s⁻¹). Fluorescence intensity per guard cell was expressed as the ratio of treated cells to untreated cells. Error bars represent standard error of the mean (n = 3). Double asterisks (**) indicate a significant difference (p < 0.01) compared with values for untreated cells