Plant organisation- leaf and stomata

• Structure of a leaf (in order)

  stomata, lower epidemis, spongy mesophyll, palisade mesophyll, upper epidermis, phloem tube
• What happens in the stomata?

  CO2 diffuses into the leaf.
• What happens in the spongy mesophyll?


  Has lots of air gaps which allows the gas to pass through the leaf quicker and easier
• What adaptations does a leaf have ?

  Guard cells around stomas, thin layer of waxy cuticle, meristem tissues
• How does guard cells help the leafs function?

  There are two guard cells for a stoma. When the leaf is well hydrated- stoma gap wider- let more co2 diffuse in.

  When the leaf is not very hydrated- stoma gap close- less co2 diffusion- reduce loss of water molecules

  Sensitive to light- more shaded and cooler where stomata are- less evapouration happens- reduces loss of water
• How does a waxy cuticle help the leafs function?

  Prevents water loss out of of top of leaf
• What is a waxy cuticle made out of?

  Thin layer of lipids
• What is a meristem tissue?


  Found at the ends of growing tops of shoots and roots.

  Can differentiate into whatever cell they want- enables growth

  Can be seen as a stem cell for plants
• How does meristem tissue help the leaf?


  Increases growth
• What do guard cells help with?


  Keep balance of water molecules and carbon dioxide inside the leaf to enable photosynthesis