Root and shoot hydraulic conductance of seven Quercus species

The root (K-R) and shoot (K-S) hydraulic conductances of seven different Qu ercus species, as well as the leaf blade hydraulic resistance (R-LL), were measured in potted plants with the aim of understanding whether a relations hip exists between the hydraulic architecture and the general ecological be haviour of different species of this genus. The K-R values were scaled by d ividing by root surface area (K-RR) and by leaf surface area (K-RL) and the K-S values were scaled by dividing by leaf surface area (K-SL). The likely drought-adapted species (Quercus suber, Q. pubescens, Q. petraea) showed l ower K-RL and K-RR, lower K-SL and higher R-LL with respect to the known wa ter-demanding species (Q. alba, re. cerris, Q. robur, Q. rubra). The possib le physiological and ecological significance of such differences are discus sed. ((C) Inra/Elsevier, Paris.).