The structure of a leaf has adaptations so that it can carry out photosynthesis effectively.
A leaf needs:
Gas exchange happens in the spongy mesophyll tissue of the leaf. Spongy mesophyll cells are covered by a thin layer of water and loosely packed.
When the plant is photosynthesising during the day, these features allow carbon dioxide to diffuse into the spongy mesophyll cells, and oxygen to diffuse out of it.
Light absorption happens in the palisade mesophyll tissue of the leaf. Palisade cells are column shaped and packed with many chloroplasts. They are arranged closely together so that a lot of light energy can be absorbed.
|Large surface area||Maximise light absorption|
|Thin||Short distance for carbon dioxide to diffuse into leaf cells|
|Thin waxy cuticle||This protects the leaves without blocking out light|
|Thin transparent epidermis||Allows light to reach the palisade cells|