A revised and unified pressure-clamp/relaxation theory for studying plant cell water relations with pressure probes: In-situ determination of cell volume for calculation of volumetric elastic modulus and hydraulic conductivity

摘要

The cell-pressure-probe is a unique tool to study plant water relations in-situ. Inaccuracy in the estimation of cell volume (v_o) is the major source of error in the calculation of both cell volumetric elastic modulus (e) and cell hydraulic conductivity (Lp). Estimates of v_o and Lp can be obtained with the pressure-clamp (PC) and pressure-relaxation (PR) methods. In theory, both methods should result in comparable v_o and lp estimates, but this has not been the case. In this study, the existing ivtheories for PC and PR methods were reviewed and clarified. A revised tvtheory was developed that is equally valid for the PC and PR methods.