Leaf O-2 uptake in the dark is independent of coincident CO2 partial pressure

Elevated CO2, in the dark, is sometimes reported to inhibit leaf respiratio n, with respiration usually measured as CO2 efflux. Oxygen uptake may be a better gauge of respiration because non-respiratory processes can affect da rk CO2 efflux in elevated CO2. Two methods of quantifying O-2 uptake indica ted that leaf respiration was unaffected by coincident CO2 level in the dar k.