Cork cambium

Definition

Cork cambium is a type of lateral meristematic tissue in plants responsible for producing the outer protective layer of bark known as cork. It forms a continuous layer of cells that divide to create new cells outwardly, which differentiate into cork cells, while internally it generates a layer of phelloderm. This tissue plays a crucial role in the plant's secondary growth, contributing to the thickening of stems and roots.

5 Must Know Facts For Your Next Test

1. Cork cambium arises from the outer layers of the stem or root and contributes to the formation of the periderm.
2. The cork cells produced by cork cambium are dead at maturity and contain suberin, making them waterproof and resistant to gas exchange.
3. As plants age, cork cambium becomes more active in producing cork, leading to the thickening of bark over time.
4. Cork cambium is critical for protecting the plant from environmental stresses, pathogens, and physical damage.
5. In some species, like the cork oak, the harvesting of cork from cork cambium does not harm the tree, allowing for sustainable production.

Review Questions

• How does cork cambium contribute to a plant's secondary growth?
  • Cork cambium contributes to secondary growth by continuously producing new layers of cork on the outer surface of stems and roots. This process increases the thickness of the plant body as it matures. As cork cambium divides, it forms new protective cork cells that accumulate over time, leading to an increase in bark thickness, which helps protect against environmental factors.
• Discuss the role of suberin in the cells produced by cork cambium and its significance for plant survival.
  • Suberin is a waxy substance found in the walls of cork cells produced by cork cambium. This material provides waterproofing and protection against pathogens and physical damage. The presence of suberin ensures that moisture is retained within the plant while also preventing harmful external agents from penetrating. This adaptation is particularly significant for terrestrial plants that need to minimize water loss.
• Evaluate the ecological importance of cork cambium in relation to its role in plant structure and function within terrestrial ecosystems.
  • Cork cambium plays a vital ecological role by enhancing plant resilience and adaptability within terrestrial ecosystems. The production of protective cork through this tissue allows plants to withstand various environmental stresses such as drought, fire, and pest invasions. Additionally, as trees with active cork cambium provide habitats and food sources for numerous organisms, their presence contributes significantly to biodiversity. Thus, cork cambium not only aids individual plant survival but also supports ecosystem health.

Related terms

Phellogen: Another name for cork cambium, highlighting its role in producing cork and phelloderm.

Secondary Growth: The process by which plants increase in thickness, primarily through the activity of vascular cambium and cork cambium.

Periderm: The protective tissue layer that includes the cork, cork cambium, and phelloderm, forming the outer bark of woody plants.