Root hydraulic conductivity (Lp) was measured according to Ramos and Kaufmann (1979) at the end of the two flooding periods on three plants of each rootstock. The root system was carefully washed, and a portion was immediately submerged in a container of water before being placed in the pressure chamber with the cut stump exposed. A small piece of tubing was fitted to the stump and connected to an Eppendorf micro tube. After obtaining a good seal, the air pressure was increased at a rate of 0.4 MPa min–1 up to final pressure of 1.0 MPa. Every three min, the exudate was collected and its volume measured. This was repeated four times, the first exudate was not included in the calculation of the mean exudate volume. Subsequently, total root length was estimated using an Image Analysis System (Delta-T Devices Ltd.). Root hydraulic conductivity was calculated using the formula