Spatial waves of clock gene expression persist in the absence of long-distance signals.

(A) Schematic depicting the experimental design. Seedlings were cut at the hypocotyl junction, RT, or at both the hypocotyl junction and the RT. The rhythm of both the excised organs and the remaining intact organs were subsequently analyzed. (B–D) Times of peaks of GI::LUC expression in different organs following a cut at the hypocotyl junction (B), RT (C), or both the hypocotyl junction and RT (D). Plots represent the 25th percentile, median, and the 75th percentile for the peak times of organs scored as rhythmic. (E–G) Period estimates of GI::LUC for different organs following a cut at the hypocotyl junction (E), RT (F), and both the hypocotyl junction and RT (G). All comparisons of means are not significantly different, p > 0.05, by two-tailed t test, Welch correction. Box plots indicate the median and upper and lower quartiles, and whiskers the 9th and 91st percentiles of organs scored as rhythmic. (H–K) Representative phase plot of GI::LUC expression across longitudinal sections of the hypocotyl and root of a single seedling without a cut (H) or with a cut at either the hypocotyl junction (I), RT (J), or both the hypocotyl junction and RT (K). Schematics show the approximate cut position and the region analyzed. Color maps are as in H. For hypocotyl cut experiments, N = 4; RT cut, N = 3; hypocotyl and RT cut, N = 3. For all, n = 9–17. N represents the number of independent experiments and n the total number of organs tracked. See S1 and S2 Files for exact n, test statistics, and percentage rhythmicity of each organ. Underlying data are available from https://gitlab.com/slcu/teamJL/greenwood_etal_2019. GI, GIGANTEA; LL, constant light; LUC, LUCIFERASE; RT, root tip.