Table 1.

Statistical analysis (ANOVA) for seasonal averages or for the final harvest data

Type of measurements	Parameters	Main effects
		[CO2]	Cultivar	[CO2]× cultivar	DOY	DOY× [CO2]	DOY×cultivar	DOY×[CO2]×cultivar
Gas exchange	A	<0.0001	<0.001	ns	<0.0001	0.030	ns	ns
	g s	<0.0001	0.006	ns	<0.0001	0.013	ns	ns
	iWUE	0.003	ns	ns	<0.0001	<0.001	0.007	ns
	C i	<0.0001	ns	ns	<0.0001	<0.0001	0.007	ns
	Apparent Vcmax	ns	ns	ns	<0.0001	ns	ns	ns
	Apparent Jmax	ns	ns	ns	<0.0001	ns	ns	ns
	gm	ns	ns	0.046	<0.0001	0.086	ns	ns
	V cmax	ns	0.039	ns	<0.0001	ns	ns	ns
	J max	ns	ns	ns	0.001	0.082	ns	ns
Plant growth	LAI	<0.0001	<0.0001	0.003	<0.0001	0.003	<0.0001	ns
	Height	0.082	<0.0001	<0.0001	<0.0001	ns	<0.0001	ns
	No. of leaves on main stem	ns	<0.0001	<0.001	<0.0001	ns	<0.0001	ns
	No. of leaves in the whole plant	0.001	<0.0001	<0.001	<0.0001	ns	<0.0001	ns
	No. of branches	ns	<0.0001	<0.0001	<0.0001	ns	<0.0001	ns
	SLA	0.049	<0.0001	ns	<0.0001	ns	0.073	ns
Plant material composition	Leaf N	ns	<0.0001	ns	<0.0001	0.009	0.013	ns
	C:N	0.009	<0.0001	ns	<0.0001	0.009	<0.0001	ns
	Protein dusk	ns	<0.0001	ns	<0.0001	ns	0.027	ns
	Protein dawn	ns	<0.0001	ns	<0.001	ns	0.005	ns
	TSC dusk	0.006	<0.001	<0.0001	<0.0001	ns	ns	ns
	TSC dawn	0.008	<0.0001	ns	<0.0001	ns	<0.0001	0.034
	Starch dusk	<0.0001	<0.0001	0.074	<0.0001	0.019	0.001	ns
	Starch dawn	<0.0001	<0.0001	ns	<0.0001	ns	0.046	ns
	TSC turnover	ns	<0.001	0.040	<0.0001	ns	ns	0.058
	Starch turnover	ns	ns	ns	ns	<0.001	ns	ns
	HCN in leaves	0.028	ns	ns	<0.0001	0.031	ns	ns
	HCN in peel of roots	ns	0.006	ns	–	–	–	–
	HCN in core of roots	ns	<0.0001	ns	–	–	–	–
Biomass and yield	Ffresh weight of roots	0.002	<0.0001	ns	–	–	–	–
	Fresh weight of AGB	0.008	<0.0001	ns	–	–	–	–
	Fresh weight HI	ns	<0.0001	ns	–	–	–	–
	Dry weight of roots	0.005	<0.0001	ns	–	–	–	–
	Dry weight of AGB	0.005	ns	ns	–	–	–	–
	Dry weight HI	ns	<0.0001	ns	–	–	–	–

The following parameters were measured: photosynthetic carbon uptake (A, µmol CO₂ m⁻² s⁻¹), stomatal conductance (g_s, mol H₂O m⁻² s⁻¹), intrinsic water use efficiency (iWUE, µmol mol⁻¹), [CO₂] inside the leaf (C_i, µmol mol⁻¹), ‘apparent’ maximum rate of carboxylation by Rubisco (apparent V_cmax, µmol m⁻² s⁻¹), ‘apparent’ maximum rate of photosynthetic electron transport (apparent J_max, µmol m⁻² s⁻¹), mesophyll conductance (g_m, mol m⁻² s⁻¹), V_cmax, J_max, leaf area index (LAI, m² m⁻²), height (cm), number of leaves on the main stem and in the whole plant, number of branches, specific leaf area (SLA, m² kg⁻¹), leaf nitrogen (g m⁻²), carbon versus nitrogen ratio (C:N), protein content (dusk and dawn; g m⁻²), total soluble carbohydrates (TSC, mmol m⁻²) and starch (mg g⁻¹) at dusk and dawn, TSC and starch turnover, hydrogen cyanide (HCN) content in leaves and roots (mg g⁻¹), fresh and dry weight of roots (g plant⁻¹), above-ground biomass (AGB, g plant⁻¹), and harvest index (HI)

The main effects are: [CO₂], cultivar, day of the year (DOY), and their interaction. Significant (P<0.1) and non-significant (ns) differences are shown in the table.