The cbl2;cbl3 double mutant is hypersensitive to ABA during stomatal movement. A to C, Representative cbl2;cbl3 stomata for ABA-induced stomatal closure (A), for ABA-inhibition of light-induced stomatal opening (B), or for light-induced stomatal opening (C). D, ABA-induced stomatal closure in the wild type and cbl2;cbl3. Rosette leaves with preopened stomata were treated with 0 or 10 µm ABA for 2 h before the apertures were measured. E, ABA inhibition of light-induced stomatal opening in the wild type and cbl2;cbl3. Rosette leaves with preclosed stomata (0 h) were illuminated for 2.5 h with (2.5 h/10 µm) or without 10 µM ABA (2.5 h/0 µm) before the apertures were measured. F, Light-induced stomatal opening in the wild type and cbl2;cbl3. Rosette leaves with preclosured stomata were illuminated for designated time points before the apertures were measured. Results in D to F are means ± se (n = 3). Each experiment includes 30 stomata from three epidermal peels. Asterisks indicate significant difference (t test, P < 0.05). Bars = 10 µm for A to C.