Epicuticular waxes also play an important role in the pathogenicity of certain fungi or in plant insect interactions . Water drops on the surface of an alchemilla leaf. Plant Physiol.
Therefore, the ability to form and maintain a hydrophobic surface layer, or cuticle , on the surfaces of airborne organs is probably one of the most important innovations in the history of terrestrial plant evolution.
Leaf surface area observed with a Scanning Microscope.
Finally, the plant cuticle presents a physical barrier to pathogens e. The waxes deposited inside the cutin matrix are called intracuticular wax es. Composed of cutin , it is rich in polysaccharides.
Videos on the Lotus effect: Figure 1. It is an extracellular hydrophobic layer that covers the aerial epidermis of all terrestrial plants. References and notes Cover photo. Guerinot Dartmouth electron microscope facility [Public domain], via Wikimedia Commons.
Thanks to its hydrophobic properties, the cuticle offers the leaf protection against desiccation and external environmental stresses.
They are lipids. For example, the development of complex cell walls for biomechanical support and structural protection of cells characterizes modern terrestrial plants. E, Diagram representing a part of the cuticle of a leaf covering an epidermal cell zone without stomata or trichome.
On the surface, the cutin is covered with a film and epicuticular wax crystals that give the leaf a more or less brilliant appearance. This observation is at the origin of the development of effective biomimetic technical materials  , such as paints or self-cleaning glass.
They have introduced new morphological and physiological characteristics that allow them to live in this new environment. The cuticle Figure 1E is divided into two areas based on its chemical composition: Hairs of varying appearance or trichomes emerge largely from the surface. However, epicuticular wax crystals promote the reflection of light by the leaf surface: