Figure 2.

Sulfate-Induced Stomatal Closure Requires ABA-Signaling Components and ABA-Downstream Effectors.

(A) and (C) Impact of ABA (gray, 50 µM) and sulfate (white, 15 mM MgSO₄) on hydrogen peroxide production in guard cells of epidermal peels of five-week-old slac1 (A), and abi2-1 and aba3-1 (C) plants. Data represent mean ± se (n ≥ 100; derived from ≥5 individual plants).

(B) and (D) Impact of sulfate (white, 15 mM MgSO₄) on stomatal apertures of the wild-type (WT), slac1 (B) and mutants deficient in ABA sensing (abi2-1, [D]) or ABA production (aba3-1, [D]). Control refers to water. Data represent mean ± sd in (B) and (D) (n ≥ 50, derived from ≥5 individual plants).

Letters indicate statistically significant differences between groups determined with one-way ANOVA (P < 0.05).