Figure 5.

Reduced stomatal aperture in the absence of exogenous ABA for triple hab1-1abi1-2abi2-2 (triple abi2-2) and hab1-1abi1-2pp2ca-1 (triple pp2ca-1) mutants. A and B, ABA-hypersensitive stomatal closing in triple hab1-1abi1-2abi2-2 mutant as compared to wild type. Plants were kept overnight in high humidity and then leaves were preincubated for 2 h in opening solution. Stomatal apertures were measured 2 h and 30 min after addition of 0, 0.01, or 0.1 μm ABA. Data represent the average of three independent experiments ± sem (n = 30–40 stomata per experiment). C and D, Leaf gas-exchange measurements reveal both reduced stomatal conductance and transpiration in triple pp2ca-1 and triple abi2-2 mutants as compared to wild type. Data represent the average of two independent experiments ± sem (n = 10 plants/experiment). *, P < 0.01 (Student's t test) when comparing data from each genotype and Col in the same assay conditions.