Measured leaf dark respiratory CO₂‐release is not controlled by stomatal conductance

AbstractLeaf dark respiratory CO2‐release (RD) is, according to some literature, dependent on the rate of leaf transpiration. If this is true, then at a given vapor pressure deficit, the leaf stomatal conductance (gs) will be expected to be a controlling factor of measured RD at any given time. We artificially lowered leaf gs by applying abscisic acid (ABA). Although leaf RD generally covaried temporally with gs, artificially lowering gs by applying ABA does not affect the measured leaf RD. These results indicate that observed diel fluctuations in gs are not directly influencing the measured leaf RD, thereby simplifying both future studies and the interpretation of past studies of the underlying environmental‐ and physiological drivers of temporal variation in leaf RD.