External Features of a Leaf

• External features of a leaf


  • network of veins
  • leaf blade
  • leaf arrangement
  • leaf stalk

  
• Network of veins (plants)


  • veins carry water and mineral salts to cells in the leaf blade
  • carries food manufactured from cells in leaf blade to other parts of the plant
• Leaf blade


  • has a large flat surface compared to its volume, increased surface area enables it to obtain the maximum amount of light for photosynthesis
  • a large, thin leaf bald increases surface area and decreases distance for diffusion of carbon dioxide, which allows carbon dioxide to rapidly reach the inner cells of the leaf
• leaf arrangement


  • leaves are organised around the stem in a regular pattern, which ensures that the leaves are not blocking one another from light and that each leaf receives sufficient sunlight
• Leaf stalk

  • the leaf stalk holds the leaf blade away from the stem so that the leaf blade can obtain sufficient light and air
  • leaves that do not have a leaf stalk (e.g. grass) have long leaf blades