Figure 1.

tir2-1 seedlings are resistant to NPA but not auxin. A, Root elongation on 5 μm NPA. B to D, Root elongation on medium containing IAA (B), 2,4-D (C), and NAA (D). E to H, Root hairs after treatment with 5 μm NPA. Seven-day-old seedlings were grown on ATS medium for 3 d before transfer to medium containing NPA. Bar = 300 μm. I to L, Col-0 and tir2-1 seedlings stained with Lugol stain. Four-day-old seedlings were transferred to medium with or without NPA and stained after 9 d. Bar = 50 μm. [See online article for color version of this figure.]