Figure 2.

(a) CO₂ assimilation rate (A), (b) stomatal conductance (g_s), (c) intrinsic water-use efficiency (WUE_in), (d) PSII-operating efficiency in light conditions (Φ_PSII), (e) photochemical quenching (qP), and (f) non-photochemical quenching (qNP) in the durum wheat cultivars Emilio Lepido (solid) and Svevo (pattern) subjected to 0 (i.e., control; white), 14 (i.e., WL14; light gray), or 35 (i.e., WL35; dark gray) days of waterlogging (DOW). Data are mean ± standard deviation. For each waterlogging duration, according to Tukey’s post hoc test (p ≤ 0.05), different letters indicate significant differences among means (p ≤ 0.05).