In vivo effects of the inhibitors. (A) 7-day-old wild type A. thaliana seedlings, the brassinosteroid synthesis mutant cpd or the signalling mutant bri1-1 were transferred to ½ MS medium containing 1 μM 24-epi-brassinolide (24-epi-BL), 30 μM compound 10 or 30 μM compound 15 and incubated for 7 days under long day conditions. All pictures were taken with the same magnification. The size bar represents 1 mm. (B) The hypocotyl length of 7-day-old A. thaliana Col-0 seedlings grown on ½ MS containing 1% sucrose and supplemented with compound 10 or 15 at the indicated concentrations were measured. The means and standard deviations were calculated from at least 25 seedlings. (C) Plants expressing BZR1-CFP were treated with the indicated compound for 1 h. Subsequently, the phosphorylation status of BZR1 was detected by western blot analysis using a GFP-antibody. A coomassie R250 stain is shown as loading control.