Fig. 2.

Diurnal profiles of metabolites in Arabidopsis plants growing in natural or fluorescent light with a 12 h photoperiod at DLI 12. Arabidopsis thaliana Col-0 plants were grown in a naturally illuminated and temperature-controlled glasshouse (L^VART, yellow circles) or a naturally illuminated polythene greenhouse with a less controlled temperature (L^VART^VAR, green circles) around the vernal equinox in 2015. Plants were also grown in a controlled-environment chamber with a 12 h photoperiod and DLI of 12 mol m⁻² d⁻¹. Artificial illumination was provided by white fluorescent tubes with a sinusoidal light profile (LT, cyan triangles). Rosettes were harvested from 4-week-old plants throughout a 24 h diurnal cycle for analysis of: (A) starch, (B) sucrose, (C) Tre6P, (D) total amino acids, (E) total protein, and (F) anthocyanins. Data are the mean ±SD (n=4). At each time point, significant differences between each pair of growth regimes are indicated by different colours: P<0.05=light blue, P<0.01=blue, P<0.001=dark blue. ZT, Zeitgeber time (hours after dawn).