Figure 3.

Application of ABA Does Not Trigger Rapid Changes of Cytosolic Ca²⁺ or pH Levels in Arabidopsis Roots.

(A) and (B) Analyses of roots of 5-d-old Arabidopsis expressing ABAleonSD1-3L21-P2A-R-GECO1 (ABA and Ca²⁺; n = 5; see [A]) in response to 10 µM ABA (t = 0 min) and 1 µM IAA (t = 30 min) and PA-17-P2A-ABAleonSD1-3L21 (pH and ABA; n = 8; see [B]) in response to 10 µM ABA (t = 0 min) and 1 mM ATP (t = 30 min). Images were acquired for 64 min at a frame rate of 10 min⁻¹. (Top) Shown are average vertical response profiles of emission ratios (R) or fluorescence emissions (F). (Middle) Signal changes (ΔR/R₀ or ΔF/F₀) normalized to 4-min average baseline recordings. An adjacent representative bright field (BF) root image is shown for orientation. (Bottom) Full image signal changes (mean ± sd).

Representative experiments are provided as Supplemental Movies 2 and 3.