How does a cork act as a protective tissue?

Cork, derived from the outer bark of the cork oak tree (Quercus suber), acts as a protective tissue through several mechanisms:

Impermeability: One of the primary functions of cork as a protective tissue is its ability to be impermeable to water, gases, and other substances. This property helps prevent water loss from the plant and protects it from external pathogens, pollutants, and extreme temperatures.

Resistance to Decay: Cork contains a substance called suberin, which is a complex fatty substance that makes cork resistant to decay, rot, and microbial attack. This resistance helps protect the underlying tissues of the plant from pathogens and decay-causing organisms.

Mechanical Protection: Cork's cellular structure consists of a matrix of air-filled cells bounded by a waterproof substance. This structure provides mechanical protection to the inner tissues of the plant against physical damage, such as abrasion, impact, or herbivory.

Insulation: Cork's low thermal conductivity makes it an excellent insulator, helping to protect the plant from extreme temperatures. It can help buffer the plant against rapid temperature changes, which can be damaging to sensitive internal tissues.

Regenerative Properties: Cork cells are produced by a specialized layer of cells called the cork cambium or phellogen. This layer continually produces new cork cells as the plant grows, allowing the plant to renew its protective outer covering over time.

Overall, cork acts as a multifunctional protective tissue that helps safeguard the plant against various environmental stresses, pathogens, and mechanical damage, contributing to the plant's overall health and longevity.