Cork acts as a protective tissue in plants through several key features:
- Dead, compact cells : Cork cells are dead at maturity and tightly packed without intercellular spaces, forming a dense, continuous layer that physically shields underlying tissues from mechanical injury and pathogen invasion
- Suberin coating : The cell walls of cork cells are impregnated with suberin, a waxy, hydrophobic substance that makes the cork impermeable to water and gases. This waterproof barrier prevents excessive water loss (desiccation) and blocks the entry of pathogens and harmful gases
- Thermal insulation : The thick cork layer provides insulation against temperature extremes, protecting inner tissues from heat and cold damage
- Mechanical protection : The cork’s structure resists physical damage such as abrasions and impacts, safeguarding the plant’s vital tissues
- Buoyancy and durability : Cork’s low density and elasticity contribute to buoyancy (helping seed dispersal in some species) and long-lasting protection as the outer protective layer renews with secondary growth
In summary, cork’s dead, tightly packed cells coated with suberin form a tough, waterproof, and insulating barrier that protects plants from water loss, mechanical injury, temperature fluctuations, and pathogen attack, ensuring their survival and health
