The outer layer in plant cells is the cell wall. The cell wall provides structural support, protection, and acts as a barrier to the entrance of pathogens, toxins, and chemical compounds. It maintains the shape and rigidity of the cell, prevents excessive water uptake, and enables plant cells to withstand physical stress and maintain their structural integrity. Additionally, the cell wall contains tiny pores called plasmodesmata, which allow for intercellular communication and the passage of nutrients, water, and signaling molecules between neighboring cells.
