Botany Transportation water

  1. Water transport functions
    • solvent for metabolic reactions
    • hydrates complex organic molecules
    • chemical reactant
    • under turgor pressure, provides rigidity
    • solute transport
  2. water moves in response to differences in water potential
  3. water potential is the difference between the potential energy of pure water and that of water in the system
  4. transpiration
    • loss of water of vapor
    • soil to root to stem to leaf to atmosphere
  5. apoplast
    continuum of cell walls and air spaces in a plant
  6. symplast
    interconnected protoplasts and plasmodesmata
  7. waters pathway in a leaf
    • moves from xylem to mesophyll cells along pressure gradient
    • evaporates from mesophyll
    • diffuses out of leave via stomata
  8. cohesion adhesion tension theory
    • continuous column of water is pulled along a continuous gradient
    • cohesion of water molecules
    • adhesion of water molecules to vessel walls
    • tensile strength of water in vessel elements
  9. water mainly moves through non-living cells or between cells
  10. Factors affecting transpiration rate
    • temperature¬†
    • water potential of air
    • wind
    • presence of leaves
    • leaf anatomy
    • plant's photosynthetic pathway¬†
    • stomatal opening and closing
  11. leaf anatomical traits that reduce transpiration rates
    • trichomes on leaf surface
    • multi-layer epidemics
    • thick cuticle
    • tightly-packed mesophyll
    • fewer stomata
    • sunken stomata
    • reduced leaf area
  12. deciduous
    lack leaves
  13. Nearly all transpirational water loss occurs through stomata
  14. factors that affect stomata open and close
    • leaf carbon dioxide
    • leaf water content
  15. translocation
    movement of substances in phloem
  16. phloem is the main pathway for sucrose and other dissolved organics
    transport from source to sink
Card Set
Botany Transportation water