Table 3.

Chlorophyll content, stomatal conductance (g_s), N and C content, and N and C isotope composition (δ¹⁵N and δ¹³C, respectively) in four durum wheat genotypes grown under ambient or elevated [CO₂] and well-watered or moderate water stress conditions (100 vs. 60% pot capacity).

	Genotype	Ambient [CO2]		Elevated [CO2]		PC	PW	PC × W
		Well-watered	Water stressed	Well-watered	Water stressed
Chlorophyll (SPAD units)	Mexa	46.0	51.3	52.3	52.5	0.049	0.122	0.156
	Regallo	45.8	52.2	50.5	47.7	0.962	0.472	0.093
	Burgos	45.0	49.4	51.3	50.8	0.178	0.470	0.369
	Ramirez	47.2	41.3	49.3	48.5	0.099	0.216	0.337
gs(mmol m−2 s−1)	Mexa	260.1	58.5	246.9	201.2	0.466	0.183	0.384
	Regallo	248.2	100.9	315.0	262.4	0.003	0.006	0.114
	Burgos	255.1	105.4	180.3	144.8	0.680	0.056	0.206
	Ramirez	248.6	140.0	166.1	253.1	0.772	0.839	0.093
N (%)	Mexa	5.04	4.79	3.85	4.34	0.016	0.675	0.212
	Regallo	5.14	4.72	3.81	3.84	0.007	0.534	0.477
	Burgos	5.05	5.16	3.63	4.78	0.174	0.323	0.410
	Ramirez	4.92	4.58	4.52	3.63	0.069	0.092	0.413
δ15N(‰)	Mexa	2.43	3.18	3.81	3.78	0.024	0.344	0.301
	Regallo	2.35	4.43	3.15	3.34	0.741	0.029	0.058
	Burgos	2.19	2.26	3.92	3.18	<0.001	0.152	0.087
	Ramirez	2.01	1.98	3.38	3.56	0.002	0.831	0.744
C (%)	Mexa	40.6	41.3	41.5	41.0	0.527	0.842	0.158
	Regallo	38.9	39.3	41.0	40.8	0.015	0.821	0.577
	Burgos	40.1	40.1	40.3	45.2	0.229	0.268	0.268
	Ramirez	42.1	40.6	40.3	36.8	0.185	0.227	0.620
δ13C(‰)	Mexa	−32.8	−29.7	−52.7	−55.5	<0.001	0.981	0.483
	Regallo	−33.4	−33.9	−53.9	−60.7	<0.001	0.205	0.265
	Burgos	−32.7	−29.0	−57.9	−50.4	<0.001	0.016	0.337
	Ramirez	−32.5	−29.8	−60.5	−52.8	<0.001	0.047	0.286

Significant effects for elevated [CO₂] (C), water stress (W) and their interaction (C × W) were determined by two-factor ANOVA (P). Significant P values are marked in bold (P < 0.05).