Net CO₂ uptake rates (P_N) were measured under relatively moderate climatic conditions in Chukurove basin Turkey.The higher temperatures and lower relative humidity in the field led to a rapid response to drought. The upper envelopes of scatter diagrams for P_N versus temperature which indicate the maximal rates at a particular temperature, were determined . As leaf temperature increased above 10 °C, for wheat under saline conditions ( near karakash on the easterm mediterranean ) the maximal P_N increased exponentially, reaching maxima of 12 μmol m^-2 s^-1.near 21.5 °C. For wheat under more favourable conditions near Adana Turkey, as leaf temperature increased above 5 °C, the maximal P_N increased exponentially, reaching maxima of 26 μmol m^-2 s^-1.near 24 °C μmol m^-2 s^-1,. Based on the Arrhenius equation, the apparent activation energies of enzymatic metabolism were 118 and 30 kJ mol^-1, for wheat under favourable and saline conditions respectively. These values are within the range determined for a diverse group of species using different methodologies. Above the temperature of maximalP _N it decreased by an average of 30 % per °C for the two cases. Such steep declines with temperature indicate that irrigation then may lead to only small enhancements in net CO₂ uptake ability. The study was supported by the ICCAP project RIHN Kyoto Japan.