Feb 22, 2015
2.41 explain how the structure of the leaf is adapted for gas exchange
- xylem brings water up from the root cells into the leaf
- water coats the spongy mesophyll cells
- water slowly evaporates from the mesophyll into the air spaces
- water vapour diffuses out of the stomata
- the concentration of the water in the leaf is less than the xylem, so more water is brought up
adaptations:
thin leaves allow for a shorter diffusion distance for the gases
air spaces around the mesophyll cells increase the internal surface area of the leaf to absorb more carbon dioxide
guard cells can change the size of the stomata accordingly (in dry climates, plants can't lose as much water, so the stomata close)