(A and B) Quantification of effects of high temperature on stomatal indices in WT and pif4 mutant (pif4 and pif4-2) abaxial cotyledons under long-day (LD; A) or short-day (SD; B) conditions. Plants were grown at 22°C for 4 days before transfer to 28°C for 10 (LD, red) or 23 (SD, maroon) more days. At these respective time points, plants were at similar developmental stage with six leaves. Controls were maintained at 22°C (gray).
(C) Changes in stomatal indices in response to high temperature in WT, pif4, and pif4-2 under LD (red) and SD (maroon) conditions (data derived from A and B). Shown are percentage changes from the “22°C–28°C” samples relative to samples grown at 22°C. (A and B) Values are mean ± SEM; ≥ 20. One-way ANOVA with post hoc Tukey HSD; p < 0.01. See also Figure S2.