Adaptations of Leaves

Tissues within a leaf

Waxy Cuticle- waterproof and helps cut down water loss in the plant
Upper Epidermis
Palisade Mesophyll layer- main site of photosynthesis
Air space- allows air to circulate to maintain a diffusion gradient
Vascular Bundle- Contains Xylem and Phloem for the transport of water and mineral ions around the plant
Spongy Mesophyll Layer
Guard Cells- control opening and closing of stomatal pores
Stomata- Site of gas exchange
Lower Epidermis

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The Leaf Blade is flat which provides a short diffusion pathyway, increases surface area to volume ratio
Spongy Mesophyll is permeated through airs spaces- this allows diffusion to take place and for gases to circulate which maintains diffusion gradients
Stomatal pores open and close to allow gas exchange to occur. This also prevents and reduces water loss which keeps surfaces moist which is important to allow gases to dissolve and diffuse
Mesophyll cells have partially permeable membranes which allows gases to diffuse in and out of cells.

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Have a large surface area to increase the available area for light absorbsion and diffusion
Leaves can orientate themselves towards the sun, this is known as phototropism
The leaf is thin to allow light to reach lower layers.
The cuticle and epidermis are waterproof
Palisade cells contain lots of chloroplasts and are elongated and densley packed together
Chloroplasts can move within the mesophyll cells to position themselves in areas with a higher light intensity
There are spaces between cells which allow carbon dioxide to diffuse into cells and for oxygen and water to diffuse away (water by osmosis)

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