Cuticle
/ˈkjuːtɪkəl/
Definition
Cuticle refers to the thin, waxy, water-resistant layer that covers the outer surface of most leaves, young stems, fruits, and other aboveground plant parts. It is a plant structure made mainly of cutin, a fatty polymer, plus waxes secreted by epidermal cells. Unlike the cell wall, the cuticle is noncellular and sits on top of the epidermis. Its main role is to limit water loss and help block pathogens and physical damage.
Function in Plants
- Water loss control: The cuticle slows evaporation from leaves, young stems, and fruits. This helps plants stay hydrated between water uptake and is especially important in dry, sunny, or windy conditions.
- Barrier against outside stress: A well-developed cuticle reduces contact with fungi, bacteria, dust, and some pollutants. It also helps limit minor surface injury and can reduce damage from intense light.
- Surface traits that affect care: Its thickness varies by species, age, and growing conditions, which helps explain why some leaves look glossy, bluish, or waxy. Those surface traits can also affect how easily water or foliar sprays spread.
- Part of land-plant adaptation: The cuticle was a key feature in the move from aquatic ancestors to life on land. By protecting exposed surfaces, it helped plants survive in air without drying as quickly.
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