Mesophyll
The mesophyll is the middle tissue layer of a leaf, sandwiched between the upper and lower Epidermis. It is the primary site of Photosynthesis in plants due to its abundance of chloroplasts. The mesophyll is divided into two distinct regions that contribute to different aspects of Photosynthesis and gas exchange:
- Palisade Mesophyll: Located just below the upper Epidermis, this layer consists of tightly packed, column-shaped cells rich in chloroplasts. Its structure maximizes light absorption, making it the primary site for the Light-Dependent Reactions of Photosynthesis.
- Spongy Mesophyll: Found beneath the palisade layer, these cells are loosely arranged with large air spaces between them. The air spaces facilitate the diffusion of gases, such as carbon dioxide entering for Photosynthesis and oxygen leaving as a byproduct.
Together, the palisade and spongy mesophyll optimize the leaf’s ability to absorb sunlight, exchange gases, and conduct photosynthesis efficiently. Their arrangement is crucial for maintaining the balance of energy production and respiration in the plant.