The relationship between ΦPSII and
ΦCO2 in WT (○, ▵) and poplar overexpressing FeSOD
(•, ▴) measured under nonphotorespiratory conditions, 1%
O2. Measurements were obtained with either varying
irradiance (○, •) or varying CO2 partial pressures
(▵, ▴). Each point represents an individual measurement.