Photorespiratory metabolism in Eleusine coracana, a C-4 plant.

Leaves of E. coracana had a characteristically low CO2 compensation point. The very low rates of photorespiration were associated with a lack of any perceptible response to varying O2 tension. Photorespiratory enzymes were present in rather low amounts and were confined to the bundle sheath cells. Experiments using diuron demonstrated recycling of CO2 in the light. The magnitude of the post-illumination outburst of CO2 (on removal of light at low ambient CO2 concentration) depended on the previous light regime experienced by the leaves; it was thought to be due to the continued decarboxylation of oxaloacetate.