The middle lamella is the outer wall of a plant cell, composed of protein and pectic compounds. This layer, which is the first to form during cell division, helps plant cells join together with other cells. This is critical for giving plants strength and stability.
The two other wall layers are the primary wall and the secondary wall. The primary wall is a rigid structure consisting of microscopic fibers embedded in a gel-like substance. This layer is reinforced by the secondary wall, which provide additional rigidity and strength. These layers ensure that plants have mechanical support, and protection from insects and pathogens.