Abstract

The aim of this study was to relate the stem water potential (????xm) measurements obtained with the Scholander type pressure chamber Pump-up model (PMS Instrument Company, Oregon, USA) to those obtained with the traditional pressure chamber model 3005 (Soil moisture, Corp. Santa Barbara, CA, USA). The trial was conducted in two year old grapevines cultivar Thompson Seedless, in which three conditions of water status were generated; hydrated plants (C1), plants under drought stress (C2) and plants with an intermediate water status (C3), in order to obtain a wide range of ????xm. For each plant ????xm was assessed at solar noon with the Pump-up and the traditional pressure chamber models. The relationship between measurements of the pressure chambers fit a positive linear function with a slope close to 1 and with a high determination coefficient (R2 = 0.999, p-value < 0.001). This indicates no difference between the pressure chamber measurements.