Hypersensitivity of poc1 to R requires phyB. The mean hypocotyl lengths of the poc1 phyB double mutant, poc1 and phyB single mutants, and the wild type (WT) after Rc treatment (16 μmol⋅m−2⋅s−1, 3 days), FRc treatment (9 μmol⋅m−2⋅s−1, 3 days), and darkness (3 days).