Chemistry – Chemistry of the environment - Air quality and climate | e-Consult

The structure of a leaf is highly adapted to maximise the efficiency of photosynthesis. Several features contribute to this:

• Broad, flat shape: This provides a large surface area to capture maximum sunlight.
• Stomata: These are small pores, primarily on the lower surface of the leaf, that allow for the intake of carbon dioxide and the release of oxygen. The stomata are surrounded by guard cells, which regulate their opening and closing to control gas exchange and water loss.
• Mesophyll cells: These are the main photosynthetic cells of the leaf, located between the upper and lower epidermis. They are packed with chloroplasts, which contain chlorophyll and carry out photosynthesis. There are two types: palisade mesophyll (located just below the upper epidermis, with tightly packed, elongated cells optimised for light absorption) and spongy mesophyll (with irregularly shaped cells and air spaces, providing a large surface area for gas exchange).
• Vascular bundles (veins): These contain xylem and phloem. Xylem transports water and minerals from the roots to the leaves, while phloem transports glucose produced during photosynthesis to other parts of the plant. The veins also provide structural support to the leaf.