Table 2.

Average value and standard deviation of physiological parameters for grapevine rootstock genotypes of Group A (1103P, 110R, M1, M3 and M4), Group B (161-49C, 420A, K5BB, Schwarzmann and SO4) and Group C (140Ru and 41B) at 20% soil water content (SWC). Groups are defined in Figure 2, according to the intrinsic water use efficiency. Pn = net photosynthesis (μmol CO₂ m⁻² s⁻¹); Gs = stomatal conductance (mmol H₂O m⁻² s⁻¹); E = transpiration (mmol H₂O m⁻² s⁻¹); Ψ_S = stem water potential (MPa). Statistical differences among groups for each parameter are defined according to Tukey’s post hoc test at a p-value of 0.05.

Parameter	Group A				Group B				Group C
Pn	2.93	±	0.66	a	1.47	±	1.15	b	3.68	±	1.62	a
Gs	35.80	±	13.40	a	28.26	±	16.16	a	67.25	±	36.23	b
E	0.77	±	0.26	a	0.66	±	0.36	a	1.38	±	0.67	b
ΨS	−0.76	±	0.13	a	−0.59	±	0.14	b	−0.66	±	0.14	ab