FIGURE 7.

Roots which had been kept horizontally for 3 hr were reoriented vertically again and maintained vertically for the indicated durations. (a) Immediately after redirecting the roots in a vertical position an end‐on image was taken 80 µm from the root apex. (b‐d) Same seedling after the indicated time of vertically growth. (e) For quantification, two regions of interest (F_top and F_bottom) were defined (see Figure 5) and the fluorescence ratio was determined (green dots). If auxin was applied 20 min before the seedlings were tilted back into a vertical position (red triangles), the equilibrium was reached much quicker. Vertical errors bars: SE of 4 independent determinations of fluorescence intensities