Figure 4.

PPD affects expression rhythms of clock-related genes in constant darkness. Transcript levels were determined in the uppermost fully expanded leaf of 3-week-old NGB5839 (WT) and ppd-3 plants entrained in SDs (12L:12D) at 20°C for 21 d before transfer to continuous darkness at Zeitgeber time (ZT) 24. Values are normalized to the transcript level of the ACTIN reference gene. Each sample consisted of pooled material from two plants, and each data point represents the mean ± se for n = 2 to 3. Light and dark are represented by white and black bars, respectively. The gray bars indicate the periods of subjective day during the period of continuous darkness. Zeitgeber time refers to the time since lights-on of the last full entraining cycle. Statistical analyses are presented in Supplemental Figure S2.