Figure EV2. Monitoring basipetal auxin transport and auxin response at root tips of Col‐0 and eir1‐4 roots transferred to ammonium or nitrate‐containing medium.

• A
  Basipetal (shootward) auxin transport measurements in Col‐0 and eir1‐4 roots grown on control Murashige and Skoog (MS) or with either nitrate or ammonium supplied media. ³H‐IAA was applied at the root tip of 7 DAG wild‐type (Col‐0) or eir1‐4 seedlings. Radioactivity was measured 6 h after application of ³H‐IAA in root segments after excision of the apical ≈ 1 mm of the root tip. Values shown are the geometric mean (± standard deviation, SD) for at least 30 seedlings. The amount of auxin transported into each root segment for Col‐0 and eir1‐4 was compared by ANOVA at P < 0.05. cpm, counts per minute.
• B–E
  Maximum intensity Z‐stack projection images of 5 DAG old Col‐0 and eir1‐4 roots expressing the DII‐Venus auxin signaling reporter 12 HAT to ammonium (B and D) or nitrate (C and E) supplemented media. “e” and “c” mark epidermis and cortex, respectively. Scale bar = 50 µm. Graphs denote normalized relative auxin levels at the respective positions. Lines represent polynomial regression fit with 95% confidence band. Data are derived from measurements of n = 8 (ammonium) and n = 10 (nitrate) roots of Col‐0 and n = 10 roots of eir1‐4 per condition.

Source data are available online for this figure.