The morphological characteristics of the xylem elements influence water ascent in the plants. Few models determine the physical process of water movement in the vascular system of plants based on the hydraulic architecture. This study aims to determine the anatomical characteristics of the xylem and potential hydraulic conductivity at different positions along of tomatoes (Solanum lycopersicum; Solanaceae). The xylem vessels characteristics were examined in four internodes using three segments in each internode. The analogy between Ohm’s law and Hagen-Poiseuille was used to determine the hydraulic conductivities. A successive decrease in the mean vessel diameters from the bottom to the top stem was observed, with a significant difference between successive decrease in the mean vessel diameters from the bottom to the top stem was observed, with a significant between different percentages of height. The variation of the hydraulic conductivity along the useful length of tomato allowed a better application of the Hagen-Poiseuille equation.
