transport systems

• Plants need water to maintain turgidity, for photosynthesis, and to keep cool
• Turgidity


  The state of plant cells being swollen and rigid, which keeps the plant upright
• Water entry into plants

  1. Water enters roots by osmosis

  2. Water moves up through xylem vessels
• Xylem


  • Hollow, dead tubes that transport water upwards
  • Supported by lignin rings
• Phloem


  • Transports sugars up and down the plant
  • Living cells with companion cells that provide energy
• Parts of a leaf

  • Cuticle
  • Upper epidermis
  • Palisade mesophyll
  • Spongy mesophyll
  • Lower epidermis
  • Veins
• Stomata


  Small pores on the underside of leaves that allow gas exchange
• Guard cells


  Cells that control the opening and closing of stomata
• Transpiration


  1. Water enters roots

  2. Water moves up through xylem

  3. Water evaporates from open stomata
• High light intensity


  Increases transpiration rate
• High temperature


  Increases transpiration rate
• Low light intensity


  Decreases transpiration rate
• Low temperature


  Decreases transpiration rate
• Wind


  Increases transpiration rate
• High humidity


  Decreases transpiration rate
• Pollution


  Decreases transpiration rate
• the heart is made up of four chambers, two atria (top) and two ventricles (bottom)