The cell wall of plants maintains the shape of plant cells, supports and strengthens plants, resists water pressure, controls cell growth, regulates metabolic processes for the plant, acts as a physical barrier for the plant, stores carbohydrates and helps with cell to cell signaling. The cell wall is a tough, yet flexible layer that surrounds the cell membrane of plant cells.
Cell walls have many functions. Their main function is to give the cell rigidity and strength. This allows plants to grow tall and hold out their leaves in order to obtain light energy to drive photosynthetic reactions.
Another important function of cell walls is to act as a physical barrier to the plant. The cell wall of plants is semipermeable and allows certain solutes and nutrients to enter the cell. However, it does not allow pathogens into the plant. This helps prevent diseases from infecting plants.
Cell walls also help promote cell-to-cell signaling through their cell walls. Portions of cell walls known as oligosaccharides can act as plant hormones. These compounds form from cell walls and stimulate plant hormone production, protect plants from pathogenic attack and induce enzymatic changes within the plant cells. Cell walls also resist water pressure changes so that plants do not burst or shrivel up in times of floods or droughts.