Values of (A) stomatal conductance (g_s mol m⁻² s⁻¹), (B) net photosynthetic rate (P_n, μmol m⁻² s⁻¹) and (C) efficiency of PSII (F_v/F_m) measured in leaves of grapevines under well-watered conditions (100%) and various drought levels (75%, 50%, 25%) at the beginning (DAY 0) and after 19 days of drought imposition Each column represents the mean ± SE. Different letters indicate significant differences (P≤0.05, Duncan’s New Multiple Range Test).