Transport systems in plants

• Plant organs


  • Roots
  • Stems
  • Leaves
• Structure of a leaf

  • Parts in bold
• Xylem vessels


  Involved in transporting Water & Minerals

  
• Water transport


  1. Water & Minerals enter a plant through Root Hairs

  2. Transported in dead xylem vessels

  
• Transpiration


  Process of water moving through a plant and its evaporation through the stomata

  
• Factors affecting transpiration rate

  • Wind speed
  • Humidity (moisture in air)
  • Temperature
  • Surface area

  
• Increased wind speed


  Increases rate of transpiration
• Increased humidity


  Decreases rate of transpiration
• Increased temperature


  Increases rate of transpiration
• Increased surface area (bigger leaves)

  Increases rate of transpiration
• Phloem


  Transports sugar (glucose) up & down the plant
• Phloem cells


  • Have Sieve Plates and associated Companion Cells

  
• Structure of a Leaf

  • Vein (consisting of xylem & phloem)
  • Lower epidermis
  • Waxy layer
  • Upper epidermis
  • Guard cells
  • Palisade mesophyll
  • Spongy mesophyll
  • Moist air space
  • Stomata
• Measuring Transpiration Rate


  • Apparatus: To measure the rate of transpiration, use a setup with a leafy shoot, a glass tube, and colored water. As the plant transpires, colored water is drawn up the glass tube, and its volume is measured over a set period of time to give the rate of transpiration.
• Increase in Humidity


  Decreases the rate of transpiration
• Increase in Temperature


  Increases the rate of transpiration
• Increase in Wind Speed

  Increases the rate of transpiration
• Investigating Environmental Changes


  1. Increase in Humidity: Put the apparatus in a (transparent) bag/container

  2. Increase in Temperature: Put a heater beside it or put it in a water bath at a higher temperature

  3. Increase in Wind Speed: Use a fan or hairdryer on a cool setting beside the apparatus