The cell wall is a thicker, tougher and slightly elastic structure located outside the cell membrane, with the role of maintaining cell shape, preventing water evaporation, material transportation and information transfer. 1. Maintain the shape of the cell, the cell wall increases the mechanical strength of the cell, and bear the internal protoplasmic body due to vesicle water uptake and expansion pressure, so that the cell has a certain shape. 2. retains water within the cell, preventing evaporation and water loss. 3. Material transportation and information transfer: the cell wall allows small molecules such as ions, polysaccharides and low molecular weight proteins to pass through, while large molecules or microorganisms, etc. are blocked outside the cell wall, preventing them from entering the cell. Therefore, the cell wall is involved in a series of physiological activities such as material transportation, information transfer, and discharge of metabolic waste.