Figure 7.

Cytosolic Ca²⁺ Transients in Root Tips of micu and Wild-Type Seedlings.

(A) Root tips of seedlings expressing NES-YC3.6 in control (Col-0) imaged under the same continuous perfusion conditions as in Figure 6A. FRET ratios of the ROI optimized in Figure 5C (dotted circles) are plotted over time. An inset serves to magnify the mild response using a different FRET ratio scale. Representative ratiometric images are shown for two selected time points with low FRET ratios, indicating low Ca²⁺, in blue and high FRET ratios, indicating high Ca²⁺, in red.

(B) Steady state FRET ratios preceding NAA application (averaged over 35-s time window).

(C) Linear rate of FRET ratio increase following NAA application (R² > 0.995).

(D) Peak FRET ratio after NAA application.

(E) Time to pass half-maximal ratio during recovery.

(F) to (J) Analogous measurements as for (A) to (E) of treatments with 0.1 mM ATP instead of NAA. n ≥ 7; error bars = sd (for each data point of the time lapse curves indicated in gray, light purple, and light green). ns: P > 0.05 and *P ≤ 0.05 (t test).