Cuticle

In biology, cuticle or cuticula refers to a more or less tough (but flexible) non-mineral covering of an organism, or part of it.

Animal cuticles

The invertebrate cuticula is a multi-layered structure outside of epidermis of many invertebrates, notably roundworms and arthropods, where it forms an exoskeleton.

In human anatomy, the cuticle refers to the fold of skin at the proximal end of the fingernail; see eponychium.

Plant cuticle

In botany cuticle is the waxy covering produced by the epidermal cells of leaves and young shoots to protect the plant from excessive water loss. The cuticle is thicker in plants living in dry climates than in those from wet climates, and tends to be thicker on the top of the leaf.

The cuticle is mostly composed of cutin and waxes. "The waxy sheet of cuticle also function in defense, forming a physical barrier that resists penetration by virus particles, bacterial cells, and the spores or growing filaments of fungi". (Freeman, 2002). Cutin, as a structural component of the cuticle, is covered with cuticular and epicuticular waxes, a mixture of hydrophobic materials containing C26 to C36 aliphatic compounds.

This is an adaptation to life on land as it no longer has constant moisture so it now needs to retain it.

References

• About the roundworm cuticle[1]
• Freeman, Scott, Biological Science. Prentice-Hall, Inc., New Jersey