covering the
cuticle of a leaf of
Hosta sieboldiana makes it
hydrophobic. Water, unable to
wet the cuticle, beads up and runs off, carrying dust and soluble contamination with it. This self-cleaning property is variously called "ultrahydrophobicity" or "ultralyophobicity" in technical journals. More popularly it is known as the
Lotus effect. In
botany,
plant cuticles are protective, hydrophobic,
waxy coverings produced by the epidermal cells of leaves, young shoots and all other aerial plant organs. Cuticles minimize water loss and effectively reduce pathogen entry due to their waxy secretion. The main structural components of
plant cuticles are the unique
polymers
cutin or
cutan, impregnated with
wax. Plant cuticles function as permeability barriers for water and water-soluble materials. They prevent plant surfaces from becoming
wet and also help to prevent plants from drying out.
Xerophytic plants such as
cacti have very thick cuticles to help them survive in their arid climates. Plants that live in range of sea's spray also may have thicker cuticles that protect them from the toxic effects of
salt. Some plants, particularly those adapted to life in damp or aquatic environments, have an extreme resistance to wetting. A well-known example is the
sacred lotus. This adaptation is not purely the physical and chemical effect of a waxy coating but depends largely on the microscopic shape of the surface. When a hydrophobic surface is sculpted into
microscopic, regular, elevated areas, sometimes in
fractal patterns, too high and too closely spaced for the surface tension of the liquid to permit any flow into the space between the plateaus, then the area of contact between liquid and solid surfaces may be reduced to a small fraction of what a smooth surface might permit. The effect is to reduce wetting of the surface substantially.
Structural coloration is also observed in the cuticles of plants (see, as an example, the so-called "marble berry",
Pollia condensata. ==Mycology==