title: Composition of the epicuticular waxes coating the adaxial side of Phyllostachys aurea leaves: Identification of very-long-chain primary amides.
abstract: The present study presents comprehensive chemical analyses of cuticular wax mixtures of the bamboo Phyllostachys aurea. The epicuticular and intracuticular waxes were sampled selectively from the adaxial side of leaves on young and old plants and investigated by gas chromatography-mass spectrometry and flame ionization detection. The epi- and intracuticular layers on young and old leaves had wax loads ranging from 1.7 μg/cm(2) to 1.9 μg/cm(2). Typical very-long-chain aliphatic wax constituents were found with characteristic chain length patterns, including alkyl esters (primarily C48), alkanes (primarily C29), fatty acids (primarily C28 and C16), primary alcohols (primarily C28) and aldehydes (primarily C30). Alicyclic wax components were identified as tocopherols and triterpenoids, including substantial amounts of triterpenoid esters. Alkyl esters, alkanes, fatty acids and aldehydes were found in greater amounts in the epicuticular layer, while primary alcohols and most terpenoids accumulated more in the intracuticular wax. Alkyl esters occurred as mixtures of metamers, combining C20 alcohol with various acids into shorter ester homologs (C36C40), and a wide range of alcohols with C22 and C24 acids into longer esters (C42C52). Primary amides were identified, with a characteristic chain length profile peaking at C30. The amides were present exclusively in the epicuticular layer and thus at or near the surface, where they may affect plant-herbivore or plant-pathogen interactions.
authors.affiliation: Department of Chemistry, The University of British Columbia, Vancouver, BC, V6T 1Z1, Canada.
authors.forename: Radu C
authors.initials: RC
authors.lastname: Racovita
authors.affiliation: Department of Chemistry, The University of British Columbia, Vancouver, BC, V6T 1Z1, Canada; Department of Botany, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada. Electronic address: reinhard.jetter@botany.ubc.ca.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Jetter
mesh_terms: D000438:Alcohols / Q000032:analysis; D000577:Amides / Q000737:chemistry / Q000494:pharmacology; D005227:Fatty Acids / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D060434:Herbivory / Q000502:physiology; D019441:Plant Epidermis / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D006109:Poaceae / Q000737:chemistry*; D014315:Triterpenes / Q000032:analysis; D014885:Waxes / Q000737:chemistry
chemical_list: D000438:Alcohols; D000577:Amides; D005227:Fatty Acids; D014315:Triterpenes; D014885:Waxes
keywords: Chain length profiling; Epicuticular wax; Fatty acid amides; Fishpole bamboo; Intracuticular wax; Phyllostachys aurea; Poaceae; Wax ester metamers