C.3.2, 3.3 - leaf cross section

• Dermal tissue

  • outer layer of cells in non-woody plants
  • dermal root tissue responsible for nutrient and water intake from soil
• Dermal tissue

  • Cuticle - waxy outer layer preventing water loss
• Dermal tissue

  • Upper and lower epidermis - responsible for gas exchange 
• Dermal tissue

  • Stomata - protects plant from disease
  • Open stoma: guard cells swell because they have water
  • Guard cells - inside stoma, controls items coming in/out of plant
  • pumps K+ into cell when hit by light
  • Lenticels - pores in woody stems that function like stomata
• Ground tissue - tissue layer under dermal tissue

  • Majority of plant
  • Gives plant strength, support, storage system
• Ground tissue

  • Palisade mesophyll tissue
  • Rigid to have exposure to sun
  • Contains chloroplasts, responsible for photosynthesis
  • Chloroplasts have chlorophyll (green pigment)
• Ground tissue

  • Spongy mesophyll tissue
  • Loosely packed tissue to allow gas exchange 
  • Moves O2 out stomata, CO2 in palisade for photosynthesis
• Vascular tissue - roots, shoots, leaves, responsible for transport in plant
• Vascular tissue

  • Xylem - moves water and minerals, roots -> leaves
  • Thick, hollow remains of cell wall (dead cells)
• Vascular tissue

  • Phloem - moves sugars, leaves -> roots
  • Long sieve tubes from living cells