DR5rev:GFP expression responds to high temperature and NPA treatment. A to H, DR5rev:GFP expression in hypocotyls and petioles (A–D) and roots (E–H) after growth at 22°C for 7 d (A, E, C, and G) or for 4 d at 22°C and 3 d at 29°C (B, F, D, and H). Bars = 200 μm in A to D and 50 μm in E to H. Arrows indicate larger cells (E and F) in the root meristem of the wild type at 29°C and smaller cells (G and H) in the root meristem of tir2-1 at 29°C. I to L, DR5rev:GFP expression in 7-d-old seedlings 4 d after treatment with 5 μm NPA. Bar = 30 μm.