The effect of oxygen on CO2 fixation by mesophyll protoplast extracts of C3 and C4 plants

Steven Huber, Gerald Edwards

Research output: Contribution to journalArticle

Abstract

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 languageEnglish (US)
Pages (from-to)28-34
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume67
Issue number1
DOIs
StatePublished - Nov 3 1975

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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