BBX21 transgenic seedlings are hypersensitive to light. (A, C, E, and G) Fluence rate response curves of 4-d-old Col, bbx21-1, and BBX21 transgenic seedlings grown under white light (A), blue light (C), red light (E), and far-red light (G) conditions. Hypocotyl lengths are in millimeters. Data are mean ± SE; n ≥20. (B, D, F, and H) Hypocotyl phenotypes of 4-d-old Col, bbx21-1, and BBX21 transgenic seedlings grown under white light (33.3 μmol/m2/s) (B), blue light (6.37 μmol/m2/s) (D), red light (59.5 μmol/m2/s) (F), and far-red light (1.46 μmol/m2/s) (H) conditions. In B, D, F, and H, Col, bbx21-1, and various transgenic seedlings are separated by dotted lines. The experiments were performed three times, with similar results. The graphs depict one of these experiments.