Detailed Summary of Cell Wall
The cell wall is a non-living, rigid structure that encapsulates the plasma membrane in both plants and fungi. Its primary roles include maintenance of cell shape, protection against mechanical injury, and prevention of infection. The composition of the cell wall varies; for example, algae have cell walls made of cellulose, galactans, mannans, and minerals like calcium carbonate, while higher plants consist primarily of cellulose, hemicellulose, pectins, and proteins.
In young plant cells, the primary wall possesses the ability to grow, allowing for cell expansion, which becomes less significant as the mature cell forms a secondary wall situated inwardly. The middle lamella, rich in calcium pectate, serves as a binding agent for adjacent cells, promoting cell-to-cell adhesion. Moreover, the plasmodesmata, tiny channels that traverse the cell walls, facilitate communication and transport between neighboring cells. Understanding the structure and function of the cell wall is crucial as it directly affects the physiological capabilities of plant cells.