Figure 4

aux1 ibr5 morphological phenotypes and auxin response. (A) Adult morphologies of wild-type, ibr5, aux1, and aux1 ibr5 plants. Six-week-old Col-0 (Wt), ibr5-1, aux1-7, and aux1-7 ibr5-1 grown in continuous light are shown. (B) Vascular patterning defects. Cleared cotyledons of 8-day-old Col-0 (Wt), ibr5-1, aux1-7, and aux1-7 ibr5-1 seedlings are shown. Scale bar = 1 mm. (C, D) aux1-7 ibr5-1 auxin-response defects. Lengths of primary roots of 8-day-old seedlings grown under yellow-filtered light at 22°C on medium supplemented with various concentrations of IBA (C) or 2,4-D (D) are shown. aux1 ibr5 roots were significantly longer than aux1 and ibr5 roots in the absence of hormone and on 5, 10, and 20 μM IBA (P ≤ 0.001) in two-tailed t-tests assuming unequal variance. aux1 ibr5 roots were significantly longer than aux1 and ibr5 roots on 20 (P ≤ 0.01), 40 (P ≤ 0.01), 80 (P ≤ 0.0001), and 120 (P ≤ 0.001) nM 2,4-D in two-tailed t-tests assuming unequal variance. Error bars represent standard errors of the means (n ≥ 16).