Epicuticular wax lipid composition of endemic European Betula species in a simulated ontogenetic/diagenetic continuum and its application to chemotaxonomy and paleobotany

摘要: Plants are excellent climate indicators and their macro-remains or pollen accumulating in geological archives serve as recorders of environmental change. In Europe birch trees contribute importantly to Holocene plant successions. They constitute the dwarf species Betula nana B. humilis, representing colder two tree birches, pubescens pendula indicative more temperate climate. Birch is highly similar preventing differentiation. We obtained unambiguous chemotaxonomic differentiation four European via cuticular wax lipids. Dominating lipid classes recent epicuticular waxes were n-alkanes (nC23 nC33), n-alcohols n-alkanoic acids (nC20 nC32), long-chain ester (nC36 nC48) differing amount distribution. After senescence lipids undergo diagenetic alteration modifying distributions found plants. Long-chain esters hydrolysis release bound n-fatty acids, adding free analogues. Simulated increased pool n-alcohol up 400%. Such modification primary patterns unaccounted for most paleovegetation studies. Proceeding diagenesis, e.g. by decarboxylation will convert these functionalized secondary into corresponding n-alkanes, compound class mostly applied paleoenvironment reconstruction. The simulated n-alkane pattern changed significantly, evidenced an increase mid-chain (nC23,nC25) homologues. Release may not only alter molecular but also isotopic composition, which cause errors paleoclimate assessed potential contribution (free decarboxylation) tertiary (bound metabolites compared cumulative with reported literature. Two statistically different separated, one dominated primary, other formed n-alkanes. This explain inconsistency previous analysis needs consideration