What is the composition of the protective layer known as the periderm?

The periderm is an important protective layer that replaces the epidermis in mature stems and roots of woody plants. Its primary composition includes cork cells, which are produced by the cork cambium, and suberin, a hydrophobic substance that impregnates the cell walls of cork cells. This combination serves to protect the plant from desiccation and environmental damage, as well as providing a barrier to pathogens.

Cork cells contribute to the structural integrity and protective functions of the periderm, while suberin enhances its water-resistant properties. Together, they help fulfill the essential roles of shielding internal tissues and regulating gas exchange through lenticels, which are openings that allow for the movement of gases.

Understanding why the composition of periderm is specifically cork cells and suberin gives insight into the adaptive mechanisms plants utilize to survive in varied environments. This knowledge is crucial for anyone studying plant science, as it highlights the complexities of plant adaptations and their functions in growth and protection.