Adaptations of leaves for photosynthesis

• Leaves are adapted to bring together the three raw materials of photosynthesis (water, carbon dioxide and light) and remove its products (oxygen and glucose).
• Leaves have a large surface area to absorb as much sunlight as possible.
• Leaves are arranged in a way that minimises overlap and shadowing of other leaves, allowing more light to reach more leaves.
• Leaves are thin, since most light is absorbed in the first few micrometres of a leaf. This also keeps the diffusion distance for gases shorter.
• Leaves have a transparent cuticle and epidermis that allows light through to the photosynthetic mesophyll cells beneath.
• Leaves have long, narrow upper mesophyll cells packed with chloroplasts to collect sunlight.
• Leaves have numerous stomata for gaseous exchange so that all mesophyll cells are only a short diffusion pathway from one.
• Leaves have stomata that open and close in response to changes in light intensity.
• Leaves have many air spaces in the lower mesophyll layer to allow rapid diffusion in the gas phase of carbon dioxide and oxygen.
• Leaves have a network of xylem that brings water to the leaf cells, and phloem that carries away the sugars produced during photosynthesis.