CO₂ and O₂ dynamics in aquatic C₃ or CAM plants

Pedersen et al. describe a new amperometric CO₂ microsensor and an O₂ microsensor elucidated the dynamics in leaf pCO₂ and pO₂ during light–dark cycles for C₃ Lobelia dortmanna (Campanulaceae) and CAM Littorella uniflora (Plantaginaceae) aquatic plants. During the dark period, for the C₃ plant pCO₂ increases, whereas for the CAM plant CO₂ remains low owing to CO₂ sequestration into malate.

The C₃ plant becomes severely hypoxic late in the dark period whereas the CAM plant with greater cuticle permeability does not. Similar to the use of O₂ microsensors to resolve questions related to plant aeration, deployment of the new CO₂ microsensor will benefit plant ecophysiology research.