Plant cuticles are a protective waxy covering produced only by the epidermal cells of leaves, young shoots and all other aerial plant organs. In addition to its function as a permeability barrier for water and other molecules, the micro and nanostructure of the cuticle confer specialized surface properties that prevent contamination of plant tissues with external water, dirt and micro-organisms. The waxy sheet of cuticle also functions in defence, forming a physical barrier that resists penetration by virus particles, bacterial cells, and the spores or growing filaments of fungi