The Effect of Light on the Oxygen Metabolism of the Photosynthetic Bacterium, Rhodospirillum rubrum.

Abstract

The effect of illumination on the rate of uptake of 02 isotopes by R. rubrum was studied manometrically and with a mass spectrometer using tracer O2 in the gas phase. Light decreased the rate of O2 consumption. Photoinhibition usually was incomplete and amounted to 60-85% in most experiments. No molecular O2 was produced in the light; therefore the effect on respiration was a true inhibition of O2 consumption rather than photosynthesis compensating for respiration.