Measured leaf dark respiratory CO -release is not controlled by stomatal conductance.

Leaf dark respiratory CO -release (R ) 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 (g ) will be expected to be a controlling factor of measured R at any given time. We artificially lowered leaf g by applying abscisic acid (ABA).