Figure 3.

Light-saturated rate of photosynthesis (a,c) and chlorophyll content index (b,d) of the flag leaf of wheat at low and high O₃ concentrations and three irrigation regimes between 28 June and 25 July. The bottom graphs (c—Asat, d—CCI) show the fraction of the values for both parameters at high compared to low O₃. The treatments were applied for the period 26 June–23 July 2018, with high O₃ exposure starting on 28 June. WW = well-watered; FD = frequent deficit irrigation; ID = infrequent deficit irrigation (with low volume applied on the day before 11 and 18 July); 30 = peak O₃ concentration of 30 ppb; 80 = peak O₃ concentration of 80 ppb. Values are averages (± SE; n = 4).