Plant Transport Systems

• Leaf


  Structure of a leaf
• Photosynthesis


  1. Occurs in palisade mesophyll

  2. Palisade cells have many chloroplasts to trap light energy
• Palisade mesophyll


  • Where most photosynthesis occurs
  • Contains palisade cells which have many chloroplasts to trap light energy for photosynthesis
• Spongy mesophyll


  • Has air spaces to allow gas exchange within the leaf
• Veins


  • Contains the xylem and phloem
• Guard cells


  • Controls the opening and closing of the stomata
• Stomata


  • Leaf pores to allow carbon dioxide to enter the leaf and oxygen/water vapour to diffuse out of leaf
  • Found on the lower epidermis
• Plants are multicellular organisms
• Plants have specialised cells, tissues and organs
• Identifying the main organs in a plant

  1. Roots

  2. Stem

  3. Leaves
• Transport of sugar in a plant

  Sugar is transported up and down the plant in living tissue called phloem
• Phloem


  • Have sieve companion cells to provide energy
  • Have sieve plates which have small pores to connect the sieve tubes to move sugar up and down the plant
• Sieve plate


  Allows sugar to move up and down the plant
• Sieve tube


  Transports sugar
• Companion cells


  Provide energy for the sieve tubes
• Transport of water in a plant

  1. Water and minerals enter the plant through root hair cells

  2. Water is transported through the plant in dead xylem vessels
• Root hair cells


  • Have a large surface area to absorb more water and minerals
• Xylem cells


  • Contain lignin rings or lignin to withstand pressure changes as water moves
• Comparing Xylem and Phloem

  • Xylem transports water, up only, non-living, lignin and hollow
  • Phloem transports sugar, up and down, living, sieve plates and companion cells
• Trampiration


  The movement of water through a plant
• Movement of water through a plant

  1. Water enters roots

  2. Water travels up the plant in the xylem

  3. Water travels to the leaves

  4. Water evaporates through stomata
• Xylem


  • Tubes that water travels up through
• Stomata


  • Openings in the leaves where water vapour diffuses out
• Transpiration


  • How quickly plants lose water
• Measuring the rate of transpiration

  1. Leafy shoot

  2. Reservoir to reset bubble

  3. Scale

  4. Bubble
• Rate of transpiration


  The distance the bubble travels over a given time
• Greater distance bubble moves in a given time

  Faster the rate of transpiration