Long-term effects of a low O2 and CO2, atmosphere on photosynthesis were studied on Sinapis alba L. It was shown that this could induce strong and durable changes on the subsequent photosynthesis measured at different CO2 and O2 concentrations. Two mains effects were observed: (1) an inhibition of net assimilation measured at 21% or 0.1% O2; (2) a qualitative change of the Warburg effect. After the treatment, high CO2 concentrations did not reverse the inhibitory effect of O2 on photosynthesis.The effect of the low O2 and CO2 atmosphere, characterized by the inhibition of net assimilation, was analyzed by varying the following factors during plants treatment: light intensity, temperature, and CO2 and O2 concentrations. The inhibition was higher under high light intensity, increased with temperature, and was apparent within the following limits of CO2 and O2 concentration, respectively, 0 to 0.018% CO2 and 0.1 to 4% O2.The results are discussed to determine if they showed that an inhibition of photorespiration in a low CO2 atmosphere has a function in the photosynthetic apparatus.
The activity of light and dark reactions of the photosynthetic apparatus with a change in light intensity. Theoretical analysis using the Farquhar model