Review session: thursday 3/12 from 5pm to 6pm. Movement of xylem sap: root pressure & transpiration-cohesion-tension. Evolve structures to transport this water from the ground. Plants used to be aquatic where they were surrounded by water. Also evolve structures that anchor them to the ground, and reach them high up. The vascular system distributes resources around the plant. Symplastic, apoplastic, and trans-membrane routes short distance transport. Short distance moves water/solute in and out of the vascular system. Bulk flow moves it all around within the system. Minerals are transported actively (up their concentration gradient) into the roots the concentration is greater in the roots than in the soil. Casparian strip (made of lignin and suberin?) excludes water. Living cells are moving ions into the apoplast. Xylem sap = the stuff in the xylem (water and minerals) Moving from root to leaves, replacing lost water.