Accumulation of circadian clock-regulated transcripts under constant blue light. Transcript accumulation in wild type (Columbia, solid black), phot1-5 (dashed red), phot2-1 (purple) and phot1-5 phot2-1 (p1p2, dotted blue) mutants was compared using qRT-PCR. Levels of GIGANTEA (A), TOC1 (B), and CCR2 (C) mRNA were assessed. Plants were entrained to 12:12 LD cycles for 12 d on ½ MS media before being moved to constant conditions with 20 μmol m−2 s−1 blue light. Data for each transcript were compared with an internal control (PP2a) before being normalized to the peak of wild-type accumulation. Data are the average of 3 biological replicates, error bars show standard error of the mean. Dark blue shading indicates subjective night.