Cutan

Cutan is one of two polymers which occur in the cuticle of some plants. The other and better-known polymer is Cutin. Cutan is believed to be a hydrocarbon polymer, whereas cutin is a polyester, but the structure and synthesis of cutan are not yet fully understood. Cutin is not present in as many plants as once thought; for instance it is absent in Ginkgo.^[1]

Cutan was first detected as a non-saponifiable component, resistant to de-esterification by alkaline hydrolysis, that increases in amount in cuticles of some species such as Clivia miniata as they reach maturity, apparently replacing the cutin secreted in the early stages of cuticle development (Schmidt and Schönherr, 1982). Evidence that cutan is a hydrocarbon polymer comes from the fact that its flash pyrolysis products are a characteristic homologous series of paired alkanes and alkenes (Nip et al. 1986)

Its preservation potential is much greater than that of cutin.^[1]

References

1. ^ ^{a b} Briggs, D.E.G. (1999). "Molecular taphonomy of animal and plant cuticles: selective preservation and diagenesis". Philosophical Transactions of the Royal Society B: Biological Sciences 354 (1379): 7–17. doi:10.1098/rstb.1999.0356. http://journals.royalsociety.org/index/7TTY8KM0Y9PADF1X.pdf 

• Schmidt, H. W. and Schönherr, J. (1982) Development of plant cuticles - occurrence and role of non-ester bonds in cutin of Clivia miniata Reg. leaves, Planta, 156, pp. 380–384.

• Nip, M., Tegelaar, E. W., de Leeuw, J. W., Schenck, P. A., and Holloway, P. J. (1986) A new non-saponifiable highly-aliphatic and resistant bioploymer in plant cuticles. Evidence from pyrolysis and ¹³C-NMR analysis of present-day and fossil plants. Naturwissenschaften, 73, pp. 579–585.

Further reading

Boom, A.; Sinningedamste, J.; Deleeuw, J. (2005). "Cutan, a common aliphatic biopolymer in cuticles of drought-adapted plants". Organic Geochemistry 36 (4): 595. doi:10.1016/j.orggeochem.2004.10.017.  edit