OPTIMIZATION MODEL OF THE STOMATAL REGULATION IN C-3 PLANTS .4. STOMATAL RESPONSE TO CHANGES IN O-2 CONCENTRATION

The optimization model of photosynthesis predicts stomatal response to changing oxygen concentration. According to the optimization statemen t, a decrease in oxygen concentration will result in a decline in CO2 concentration in the leaf intercellular spaces (c(i)), accompanied by an enhancement of photosynthesis. Because we have failed to find satis factory data in the literature, we estimated the predicted changes in ci and photosynthesis for those cases, in which the oxygen concentrati on was reduced from 21% (ambient air) to less than 2%. Typically, low O-2 concentrations should decrease c(i) by 30 - 50 ml/l and increase p hotosynthesis by 40%. These estimates are consistent with the literatu re data. Furthermore, the predictions of the model were directly confi rmed by the data obtained on six plant species.