Cutan is one of two biopolymers which occur in the cuticle of some plants. The other and better-known polymer is

cutin Cutin is one of two waxy polymers that are the main components of the plant cuticle, which covers all aerial surfaces of plants. It is an insoluble substance with waterproof quality. Cutin also harbors cuticular waxes, which assist in cuticle st ...

. Cutan is believed to be a

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...

polymer, whereas cutin is a polyester, but the structure and synthesis of cutan are not yet fully understood. Cutan is not present in as many plants as once thought; for instance it is absent in ''

Ginkgo ''Ginkgo'' is a genus of non-flowering seed plants. The scientific name is also used as the English name. The order to which it belongs, Ginkgoales, first appeared in the Permian, 270 million years ago, and is now the only living genus with ...

''. Cutan was first detected as a non- saponifiable component, resistant to de-

esterification In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

alkaline hydrolysis Alkaline hydrolysis, in organic chemistry, usually refers to types of nucleophilic substitution reactions in which the attacking nucleophile is a hydroxide ion. Example In the alkaline hydrolysis of esters and amides the hydroxide ion nucleophi ...

, that increases in amount in cuticles of some species such as ''

Clivia miniata ''Clivia miniata'', the Natal lily or bush lily, is a species of flowering plant in the genus ''Clivia'' of the family Amaryllidaceae, native to woodland habitats in South Africa (Eastern Cape, Mpumalanga and KwaZulu-Natal provinces) as well as ...

'' as they reach maturity, apparently replacing the cutin secreted in the early stages of cuticle development. Evidence that cutan is a hydrocarbon polymer comes from the fact that its flash

pyrolysis The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements ''py ...

products are a characteristic homologous series of paired alkanes and

alkene In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...

s (Nip ''et al.'' 1986) Its preservation potential is much greater than that of cutin.

References

Notes

*''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.''

References

Notes

Further reading