Figure 1.

Induction of stomatal closure and inhibition of light-induced stomatal opening by ABA in the wild type (WT) and the pyr/ pyl1/py2/pyl4 quadruple mutant (quadruple). A, ABA-induced stomatal closure in the wild type and the quadruple mutant. Averages from five independent experiments (n = 5; a total of 100 stomata) are shown. B, ABA inhibition of stomatal opening in wild-type and quadruple mutant plants. Dark represents fully dark-adapted stomata; 0 µm ABA indicates 2.5-h light treatment after the dark adaption with 0.1% ethanol as the solvent control; 1 and 10 µm ABA represent an ABA addition at the same time as the initiation of light treatment. Averages from three independent experiments are shown (n = 3; 60 total stomata). Asterisks indicate significant differences (**α = 0.01) by Student’s t test. A data set obtained by Y.Y. is shown out of the results carried out by three independent examiners, with Y.Y., Y.A., and I.C.M. obtaining essentially the same results. Error bars represent se.