Specialised Cells

PALISADE LEAF CELLS ARE ADAPTED FOR PHOTOSYNTHESIS packed with choloplasts for photosynthesis. More of them are crammed at the top of the cell - so they,re nearer the light. Tall shape means a lot of surface area exposed down the side for absorbing CO2 from the air in the leaf. Thin shape means that you can pack loads of them in at the top of a leaf. Palisade leaf cells are grouped together at the top of the leaf where most of the photosynthesis happens.

GUARD CELLS ARE ADAPTED TO OPEN AND CLOSE PORES  Special kidney shape which opens and closes the stomata in a leaf. When the plant has lots of water the guard cells fill with it and go plump and turgid. THis makes the stomata open so gasas can be exchanged for photosynthesis. When the plant is short of water, the guard cells lose water and become flaccid, making the stomata close. This helps stop too much water vapour escaping. Thin outer walls and thickened inner walls make the opening and closing work. They,re also sensitive to light and close at night to save water without losing out on photosynthesis. Guard cells are therefore adapted to their function of allowing gas exchange and controlling water loss within a leaf. 

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