the leaf

• Meristem tissue


  Plant form of stem cells, found at growing tips, can differentiate into many cell types
• Leaf


  Plant organ
• Leaf


  • Contains many different tissues
  • Tissues make up organs
  • Organs make up organ systems
  • Organ systems carry out tasks for plant survival
• Tissues in a leaf

  • Epidermal tissue
  • Spongy mesophyll tissue
  • Xylem
  • Phloem
  • Palisade mesophyll tissue
  • Stomata
  • Guard cells
• Epidermal tissue


  • Covers the surface of the whole plant
  • Includes upper and lower epidermis
• Waxy cuticle


  • Covers the epidermal tissue
  • Reduces water loss through evaporation
• Upper epidermis


  • Transparent layer
  • Allows light to pass through to palisade cells
• Palisade mesophyll cells


  • Located near the top of the leaf
  • Receive the most light
  • Contain many chloroplasts to maximize photosynthesis
• Xylem


  Transports water and nutrients from roots to leaves
• Phloem


  Transports glucose made during photosynthesis away from leaves
• Stomata


  • Holes in the lower epidermis
  • Allow carbon dioxide and oxygen to diffuse in and out
  • Control water loss (transpiration)
• Guard cells


  • Surround stomata
  • Control the opening and closing of stomata
• Air spaces in spongy mesophyll

  • Increase diffusion of gases through the leaf
  • Leaves are broad to increase surface area exposed to light
  • Maximizes photosynthesis
• Plant tissues


  • Their structures are related to their functions
• The leaf is a plant organ adapted specifically for photosynthesis
• The structure of a leaf maximises the diffusion of carbon dioxide into the mesophyll cells for photosynthesis
• The structure of a leaf enables air to circulate within it to maximise the diffusion of carbon dioxide to the chloroplasts for photosynthesis
• meristem is the type of tissue in plants that contains stem cells