bio 3.2 power points

• Vascular plant systems


  • Shoot system (above ground)
  • Root system (below ground)

  
• Shoot system organs


  • Stem
  • Leaf
  • Flower
  • Fruit/seed

  
• Root system organs


  • Main root
  • Lateral root
  • Root hairs
• Plant tissues


  • Meristematic tissue
  • Permanent tissue

  
• Permanent tissues


  • Dermal
  • Ground
  • Vascular
• Meristematic tissue


  Can still divide
• Permanent tissue


  Can no longer divide
• Dermal tissue

  • Protects plants and minimises water loss
• Ground tissue


  • All tissues that are not dermal or vascular
• Vascular tissue


  • Composed of xylem and phloem

  
• Functions of meristematic tissue

  • Allowing plants to grow vertically in length
  • Allowing plants to grow in diameter, increasing the girth of the plant
  • Repairing and regenerating damaged parts

  
• Dermal tissue - Epidermis


  • Outermost layer of cells in leaf, stem and roots

  
• Dermal tissue - Guard cells


  • Modified epidermal cells forms the opening of stomata
• Types of parenchyma

  • Chlorenchyma (with chloroplasts)
  • Aerenchyma (with air voids)
  • Storage parenchyma

  
• Collenchyma


  • Composed of elongated living cells with thick but flexible primary cell walls
• Sclerenchyma

  • Provides rigidity and strength to many plant organs
  • Composed of cells with thickened secondary cell walls
  • Mature sclerenchyma cells are dead
• Xylem


  • Consists mainly of hollow dead cells with thick cell walls hardened by lignin
  • Transports water and dissolved minerals throughout a plant
• Phloem


  • Consists of living cells that transport sugars, in the form of dissolved sucrose (table sugar), and other organic compounds, including hormones, throughout a plant
• Tissues involved in movement of water

  • Xylem (tracheids and vessels)

  
• Tissues involved in the loss of water

  • Air spaces in spongy mesophyll tissue
  • Stomata
• Stomata


  • Located mainly in the lower epidermis of leaves
  • Exit points for water vapour diffusion

  
• Air spaces in spongy mesophyll tissue are usually saturated with water vapour
• Stomata are the action points for water loss