BIO203H5 Chapter Notes - Chapter 37: Water Potential, Potential Gradient, Root Pressure
Document Summary
Water loss is a side effect of photosynthesis. Air in surrounding dryer than leaf (>100 humidity) Water moves passively, differences in potential energy of water (stored energy) Water potential - potential energy of water compared to pure water at room temp. High in roots, low in leaves (water potential gradient) Isotonic - solute concentrations in cell and surrounding are the same. Solute potential /osmotic potential - water moves from low solutes concentration to high solutes concentration. Wall pressure - when plant cell walls prevent cells from bursting by osmosis of water in. Turgor pressure/turgid - pressure from the inside pushing out (ie. water) Water moves from high solute to low solute potential when permeable membranes are present. Water moves from high pressure to low pressure when no membrane are present. Pressure potential + solute potential = potential energy of water at position (megapascals) Solute potentials are almost always negative in cells (pure = 0) (high -> low)
