BISC 101 Lecture Notes - Lecture 10: Xylem, Water Potential, Symplast
16 Jun 2016
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Amazing thing, it doesn"t take energy to transport water. Transpiration: drives bulk flow of h2o and nutrients from roots shoots using the xylem. Creates a force that pulls xylem sap upwards. Regulated by the stomata and guard cells. Increased surface tension pulls water from surrounding cells and air spaces due to cohesion: water from xylem pulled into the surrounding cells and air spaces to replace water lost creating transpirational pull. Xylem sap: transports water and minerals upwards from roots shoots. Phloem sap: transports sugars in both directions from sites of production (leaves) to sites that store it (roots) Short-distance transport: occurs in the apoplast (outside plasma membrane) and symplast (cytoplasm + plasmodesmata) Water likes to move from high low water potential depending on: Water potential: determines the movement of water. Solute (osmotic) potential: s the tendency of water to move by osmosis due to difference in [ ]
