Fig. 3From: A method to experimentally clamp leaf water content to defined values to assess its effects on apoplastic pHMeasurement of leaf water content (LWC) and vapour pressure deficit (VPD) during an experiment using first (0–120 min) feedback-control of air humidity to perform a step change in air humidity and (120–280 min) feedback control of LWC to perform step changes of LWC. In the first part, leaf water content fluctuates dynamically as a result of changing leaf water balance. In the second part, LWC is fixed, and VPD is varied by feedback control as required to clamp LWC at constant set-pointsBack to article page