Pressure clamp method to measure transpiration in growing single plant cells : demonstration with sporangiophores of phycomyces.

A pressure probe method (pressure clamp) was developed to measure transpiration rates of both growing and nongrowing single plant cells, and represents an improvement over the previous pressure probe method (pressure relaxation), which is restricted to nongrowing plant cells (J.K.E. Ortega, R.G. Keanini, K.J. Manica [1988] Plant Physiol 87: 11-14). The pressure clamp method was used to measure transpiration rates of Phycomyces sporangiophores in two developmental stages: stage III (nongrowing) and stage IV (growing).