Figure 1.

Functional ABI1 and OST1 are essential for sulfate-induced stomatal closure in Arabidopsis. (a) Representative guard cell in epidermal peels of 5-weeks–old soil-grown wild-type, abi1-1, and ost1-2 plants that were floated on water at pH 5.5 or water supplemented with sulfate (15 mM MgSO₄) for three hours. (b) Quantification of the stomatal aperture of guard cells in epidermal peels from plants indicated in (a) that were treated with water (control, black) supplemented with sulfate (15 mM, yellow). Letters indicate statistically significant differences between groups determined with the one Way ANOVA test (p < 0.05, n = 50 stomata, derived from epidermal peels of five individual plants). Values represent means ± standard deviation (SD). Scale bar, 10 µm.