Increase in net photosynthesis when [O2] decreases to 2% (from 21%)

Range ~45 %
Organism C3 plants
Reference William L. Ogren, Photo respiration: pathways, regulation, and modofocation, Ann. Rev. Plant Physiol. 1984. 35: 415-42 link p.416 2nd paragraph
Primary Source [33] Chollet, R., Ogren, W. L. 1975. Regulation of photorespiration in C3 and C4 species. Bot. Rev. 137: 79 [41] Forrester, M. L., Krotkov, G., Nelson, C. D. 1966. Effect of oxygen on photosynthesis, photorespiration and respiration in detached leaves. I. Soybean. Plant Physiol. 41: 422-27 [50] Hesketh, J. 1967. Enhancement of photosynthetic CO2 assimilation in the absence of oxygen, as dependent on species and temperature. Planta 76: 371-74 doi: 10.1007/BF00387543.PubMed ID16656271, 24549501
Comments p.416 2nd paragraph:"The earliest report of what [investigators] now know to be a manifestation of photorespiratory activity was made by Warburg, who observed O2 inhibition of CO2 fixation in Chlorella (ref 128). A second manifestation of photorespiration, O2-stimulated CO2 evolution in the light, was found by Decker (ref 35). The sum effect of these two O2 effects on net photosynthesis can be estimated by comparing photosynthesis rates at 340 µL/L CO2 in 21% O2 with those observed in 2% O2. In 2% O2, net photosynthesis in C3 plants is increased by about 45% (primary sources). It is this dramatic stimulation of CO2 fixation under conditions in which photorespiration is suppressed that has encouraged attempts to regulate this process."
Entered by Uri M
ID 111954