BIOL 1106 Chapter Notes - Chapter 37: Water Potential, Endodermis, Xylem

• School: Virginia Tech
• Department: Biological Sciences
• Course: BIOL 1106
• Professor: Jack Evans

Document Summary

Local changes result in long distance movement of materials. Water moves across cell membranes of root cells, into the vascular stele and the xylem. Transpiration (evaporation from thin films of water in the stomata) [provides the main force for moving water and ionic solutes from roots to leaves] causes the pulling" force (occurs because water molecules stick to each other. [cohesion] and to the walls of tracheids or xylem [adhesion] Osmosis is aided by membrane channels called aquaporins; they exist in vacuoles and plasma membranes. While they speed up the process of osmosis, they don"t change the direction of the water; they"re important in maintaining water balance in cells and in water moving into the xylem. Water potential regulates movement of water through the plant. Potentials are a way of representing free energy. Water potential is used to predict which way water will move.