(i.e. combining data from 290, 400 and 700 ppm grown plants,the average rates of 0.5vowere 1.09 ± 0.1 ?mol CO2m−2s−1at 21%O2and 0.10 ± 0.02 ?mol CO2m−2s−1at 2% O2), with the rates of photorespiration at 2% being highest in plants grown and mea-sured at 290 ppm CO2. Changes in measurement [CO2] also has significant effects on rates of 0.5vo in 290 and 400 ppm [CO2] grown plants (Fig. 4D), although the reductions in 0.5vo were not as great at 700 ppm measurement CO2 as was the case when measured at 2% O2. Irrespective of the measurement [CO2], overall rates of 0.5vo were also generally lower in 400 ppm [CO2] grown plants compared to their 290 and 700 ppm [CO2] grown counterparts (Fig. 4D).Collectively, these treatments provided a wider range of photorespiratory rates (with potential impacts on RLand RL/RD)