Inhibition of wild-type, miz1-1, and MIZ1OE root development by plant growth hormones. A to D, Four-day-old seedlings were transferred to medium containing several concentrations of NAA (A), BAP (B), ACC (C), or ABA (D). Root growth was expressed relative to growth without hormone (n = 15–30). Asterisks indicate statistically significant differences from the wild type (Col) determined using Student’s t test (P < 0.01). E, Lateral root (LR) densities of wild-type, miz1-1, and MIZ1OE seedlings grown on BAP-containing medium. Lateral root densities were counted 6 d after transplantation (n = 23–25). Asterisks indicate statistically significant differences between Col and miz1-1 as determined by Student’s t test (P < 0.05). Error bars represent se.