Form 1:
Nutrition in Plants and Animals

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Adaptations of the leaf to photosynthesis

•The leaf has a flat and broad lamina to increase surface area for trapping sunlight energy and for gaseous exchange.

Image:Parts of a leaf

•The leaf has numerous stomata through which photosynthetic gases diffuse.

Image:Stomata

• The leaf is thin to reduce the distance through which carbon (IV) oxide has to diffuse to the photosynthetic cells.

Image:Thin leaf

• The palisade mesophyll cells contain numerous chloroplasts which contain chlorophyll molecules which trap sunlight energy for photosynthesis.

Image:Palisade mesophyl

•The photosynthetic mesophyll is located towards the upper surface for maximum absorption of sunlight energy.

•The leaf has an extensive network of veins composed of xylem which conducts water to the photosynthetic cells and phloem to translocate manufactured food materials to other plant parts.

•The epidermis and cuticle are transparent to allow light to penetrate to the photosynthetc cells.

Raw materials for photosynthesis

Water

Carbon (IV) oxide

Conditions for photosynthesis

Light energy

Chlorophyll

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