Oxygen inhibits CO2 fixation by mesophyll protoplast extracts of the C3 plants, Hordeum vulgare and Triticum aestivum, but stimulates the pyruvate induced CO2 fixation by mesophyll protoplast extracts of the C4 plants Digitaria sanguinalis and Urochloa panicoides. The former is reversed by increased levels of bicarbonate, whereas the latter effect is independent of bicarbonate concentration. The results are consistent with the proposal that oxygen inhibits C3 photosynthesis by competing with CO2 in the RuDP carboxylase/oxygenase system. The oxygen enhancement of C4 mesophyll photosynthesis is proposed to be due to pseudocyclic electron flow supplying additional ATP for the CO2 fixation process.
|Original language||English (US)|
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Nov 3 1975|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology