a. Pseudo-colored, optical longitudinal cross sections of 5 DAG roots expressing PIN2::PIN2-GFP, eir1-4 12 HAT to ammonium or nitrate supplemented media. "e" denotes epidermis and "c" cortex, respectively. Color code represents GFP intensity from low (blue) to high (white) values. Scale bar=20 µm. Box plots display the distribution of the cell membrane derived PIN2-GFP fluorescence intensity (FI) values (in arbitrary units, a.u.) on ammonium (grey, epidermis (ep) and red, cortex (co), n=15) and nitrate (blue, epidermis (ep) and green, cortex (co), n=10) grown roots. 5 cells per root were analyzed. The statistical significance was evaluated with ANOVA at p<0.05. The box chart components are defined as; box (25%-75%), central band (median line), central box (mean) and the range is within 1.5IQR. 