Root length (mm)

1. A MS Cu WT WT C1OE C1OE C3OE C3OE LDHH LLHC C B 4 3 2 1 0 30 3 ** 20 2 ** Root length (mm) LDHH ** ** ** ** 10 1 ** F.W. / seedling (mg) 4 3 2 1 0 0 0 20 2 LLHC ** ** ** 10 ** ** 1 ** 0 0 E D 4 80 3 60 LDHH 2 40 * * 1 20 * Total anthocyanins / F.W. (mmol/g) MDA / F.W. (µM/g) 0 0 ** ** 3 60 LLHC 2 * 40 1 20 0 0 WT C1OE C3OE WT C1OE C3OE WT C1OE C3OE WT C1OE C3OE MS Cu MS Cu Figure S5. Effects of the cycling conditions on the COPT1- and COPT3-overexpressing Arabidopsis seedlings. A, WT, C1OE and C3OE seedlings grown verticallyon MS plates either without (MS) or with 10 mM CuSO4 (Cu)under 6 neutral days in the absence of thermocycle (LDHH) or photocycle (LLHC). B, Quantification of the fresh weight (F.W.) of the WT (plain bars), C1OE (stripped bars) and C3OE (dotted bars) seedlings grown on MS (white bars) or Cu (gray bars), as indicated in A. Values are the F.W. per seedling as the means ± SD (n ≥ 7) from three independent experiments. C, Quantification of the root length of the seedlings as indicated in B. Values are the seedling means ± SD (n ≥ 36) from at least three independent experiments. D, Quantification of the lipid peroxidationof the seedlings, as indicated in B. Values are the MDA content per F.W. as the means ± SD of at least two independent experiments. E, Quantification of total anthocyanins content of the seedlings, as indicated in B. Values are total anthocyanin content per F.W. as the means ± SD of at least 2 independent experiments. Asterisks indicate statistically significant differences with respect to WT (*P < 0.05; **P < 0.01).