Fig. 4.

Compounds A-C inhibit auxin-mediated proteolysis, and compounds A and B inhibit primary root elongation. (A) Seven-day-old HS::AXR3NT-GUS seedlings were heat shocked at 37°C for 2 h, followed by a 20-min incubation at 23°C. The indicated concentration of compound and/or NAA was added to the medium, and the seedlings were incubated for an additional 2 h (-NAA) or 40 min (+NAA) before quantification of GUS activity (Lower). Error = SE of the mean (n = 6). (Upper) Root tips from a representative seedling of each treatment stained with X-gluc. (B) Seedlings (Col-0) were germinated and grown vertically on medium containing increasing concentrations of compound A or B. (Upper) Primary root length was measured after 8 days of growth. Error = sample SD (n > 12). (Lower) Representative seedlings from each inhibitor treatment.