Figure 2.

Period length of IRT1 promoter activity is lengthened in long-period clock mutants. A and B, Seedlings of the indicated genotypes growing on minimal medium were entrained to photocycles (LD 12/12 h) for 6 d before release in LL. Average traces (mean ± se, n = 12–24) are shown, normalized to the average activity over the duration of the experiment, of ProIRT1:LUC (A) and ProCCA1:LUC (B) expression. White and gray bars indicate subjective day and night, respectively. C, Period versus relative amplitude error (RAE) of ProIRT1:LUC and ProCCA1:LUC expression. RAE is a measure of the strength of the oscillation, with RAE = 0 corresponding to a perfect sine wave and RAE = 1 defining the lower limit of statistically significant rhythmicity. Error bars represent se. Different letters indicate significant differences (P < 0.0001) as determined by ANOVA.