Leaf Structure

Paijar Team

Thu, 19 Sep 2024

It is necessary for you to understand how a leaf's structure is modified for photosynthesis. We shall go through each structure's purposes as shown in the above diagram:

Wax-based cuticle that protects the leaf from the elements
Upper epidermis: A defense against pathogenic microorganisms. To let light into the leaf, the cells are transparent and thin.

The primary site of photosynthesis is called palisade mesophyll. To capture light energy, cells are lengthy and densely packed with chloroplasts. Through diffusion from the air gaps in the spongy mesophyll, they get carbon dioxide.
Spongy mesophyll: The cells are loosely packed and spherical in shape. Though not as many as in the palisade layer, they do contain chloroplasts.

Gas exchange is made possible by loose packing, which provides air spaces that let carbon dioxide enter cells and oxygen exit them.

Phloem and xylem are contained in the vascular bundle. Water and minerals are delivered to the leaf by xylem channels. Translocation occurs when carbohydrates and amino acids are moved from the leaf to the rest of the plant via phloem vessels.
Lower epidermis: Serves as a barrier. It has stomata in it.
Stomata: A pair of guard cells encircles the openings in the leaf's underside. The guard cells regulate the stoma's open/closed state. Carbon dioxide diffuses into the leaf and oxygen diffuses out through stomata. During transpiration, water vapor is also lost through this structure.