Gas exchange in plants is slightly similar to that of insects.
- No living cell is very far away from the externail air, and so is not very far away from a source of carbon dioxide and oxygen.
-Diffusion takes place in the gas phase (AIR), which makes it more rapid than if it were in water.
THEREFORE, there is a very short diffusion pathway. Also, a plant leaf has a very large surface area to volume ratio. For these reasons, there isn't a specialised transport system needed for gases, which just move in and out of the plant by diffusion. Most gaseous exchange occurs in the leaves, which are adapted for rapid diffusion because:
- They are a thin, flat shape, that provides a large surface area
- Many small pores, called stomata, mostly in the lower epidermis.
- Numerous interconnecting air-spaces that occur throughout the mesophyll.
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