Leaf Anatomy

A plant leaf is composed of several layers. On the outside of the leaf, both top and bottom, there is a waxy layer called the cuticle. This layer helps to prevent water loss from the leaf so that the plant can have more control over its transpiration rates. The next layer is the epidermis, which is also on the top and bottom of the leaf. This layer serves primarily for protection of the internal structures of the leaf. The next layer from the top is the palisade layer. This layer is denesly packed and is primarily used for photosynthesis. The final layer from the top is the spongy mesophyll layer. This layer is thick, but loosely packed together. While it has some photosynthetic function, its primary purpose is to facilitate the gas exhanges within the leaf.