Traces (a, b) of the CCA1-LUC (Ostreococcus) or per2:luc (U2OS cells) reporters, showing the effect of inhibition of magnesium transport by Co(NH3)5Cl2+ (CPA) upon period dose-response (c, d) and upon [Mg2+]i (e, f). All plots show mean±SEM, with replicate numbers (n) indicated, p-values report significance by 1-way ANOVA and post-test for linear trend.