Leaf of plan gas exchange

• Structure of a leaf : 

  • Short (fast) diffusion pathways
  • Very large surface area compared with volume of living tissue
• Most gas exchange occur in the leaf: Adaptations for rapid diffusion

  • Many small pores are called stomata ( allow gases to move in and out), no cells far from stoma therefore the diffusion pathway is short.
  • Numerous interconnecting airspaces that occur throughout mesophyll so gases can readily come in contact with mesophyll cells.
  • Large surface area of mesophyll cells for rapid diffusion
• What is the stomata?

  • Minute pores occurring mainly in the leaves
  • Each stoma is surrounded by a pair of guard cells, these cells and open and close the stomata pore.
  • So they can control rate of gaseous exchange
  • Guard cells are important are important as terrestrial organisms lost water via evaporation therefore plants have evolved to balance conflicting needs of gas exchange and control of water loss, they do this by closing the stomata at times where water loss is excessive