Figure 6.

PQ treatment restores the distribution of the PIN2-GFP signal in Atcrk5-1 Arabidopsis root meristems during gravistimulation. Distribution of the PIN2-GFP signal in 6-days-old AtCol-0 wild type (A–D) and mutant Atcrk5-1 (E–H) seedling roots without (A,C,E,G) or treated with 4 μM PQ (B,D,F,H). Vertically-grown (A,B,E,F) and gravistimulated (−135° rotation for 4–5 h; C,D,G,H) roots were compared. (I) Quantification of the PIN2-GFP fluorescence intensity ratio by investigating the average pixel intensities measured in equally sized areas at both sides of the GFP signals by ImageJ/Fiji. At least 5–10 images from wild type and mutant categories were analysed in each version from three independent experiments. Values near zero represent a symmetrical DR5::GFP signal position, while values higher than 0 mean an asymmetrical PIN2-GFP signal position. Asterisks indicate significant difference between the corresponding mock control and the treatment (two-way ANOVA, means comparisons was carried out by Bonferroni; *** p < 0.001). The fluorescence intensity was translated into a colour code (scale is in the middle). White arrows show the direction of the gravity vector. Red arrowheads indicate the lateral redistribution of the PIN2-GFP signal towards the gravity vector. Rectangles on (A,C) images represent the equally sized areas. Scale bar: 50 µm. The original fluorescent images (without heatmap) are shown as Figure S3.