Figure 7.

Enhanced gravitropic responses of the atmdr1 and atmdr1/atpgp1 double mutant. A, Representative root images of wild-type (Col), atmdr1-100, atpgp1-100, and atmdr1-100/atpgp1-100 mutant seedlings 24 h after gravistimulation. Seedlings were grown vertically on unsupplemented germination plates in darkness for 2 d, and then the plates were rotated 90°. Bar = 1 cm. Arrows indicate the gravity vector. B, Time course of root gravitropic response. The angles of curvature were measured every 6 h over a 24-h period. Bars indicate sds from 35 to 40 seedlings. C to E, GUS staining of seedlings 0 (before gravistimulation), 3, and 5 h after reorientation, respectively. Seedlings of wild type (Col) and atmdr1-100 mutant harboring DR5::GUS reporter gene were grown vertically on germination plates under white light for 4 d, and then were transferred to new plates for 24 h. The plates were then rotated 90°. At the indicated times, seedlings were harvested for GUS staining. Bar = 100 μm. Arrow indicates the gravity vector.