Figure 8. The effect of BR on auxin-regulated root elongation and lateral root formation.

Seven-day-old seedlings grown on solid MS medium of wild-type (Col-0) and dwf4 mutant Arabidopsis (in a Col-0 background) were transferred to the same medium containing different combinations of BL (1 nM), Brz (500 nM) or IAA (1, 10 or 100 nM) for 3 more days. The lengths of the lateral (A) and primary roots (B) and the number of lateral roots (C) of the seedlings were then measured. For the primary roots, the elongation was calculated by subtracting the root length at the initial point (day 7) from the total root length at day 10. The primary root elongation rate (B) refers to the average elongation rate (mm/d). The histograms in each graph show the means ± SE of triplicate experiments (Col-0; n = 10, dwf4; n = 8 to 10). Statistical analyses were performed separately for each data set obtained using wild-type and dwf4 plants. The different letters on the tops of the histograms indicate a statistically significant difference of P<0.01 using a one-way ANOVA followed by Tukey's test.