Adding solutes to a region decreases its water potential. Describe the process of mineral ions uptake into roots by active transport. Absorption takes place near root tips. Soil solution flows through epidermis, crosses root cortex, passes into the stele. The endodermis is the last checkpoint for the selective passage of minerals from the cortex into the vascular tissue.
Root cells expend energy during the night to pump mineral ions into the xylem.
The endodermis prevents leakage of these ions back out of the stele. Accumulation of minerals in stele lowers water potential, and water flows in. This creates a pressure that pushes water upwards and is called root pressure. Branching, root hairs, and cortex cell walls provide large surface area for mineral ion and water uptake. Transpirational pull takes place at the leaves.