Fossil Record 24(2): 321-337, doi: 10.5194/fr-24-321-2021
Experimental induction of resins as a tool to understand variability in ambers
expand article infoLeyla Seyfullah, Emily A. Roberts§, Phillip E. Jardine|, Alexander R. Schmidt
‡ Unversity of Vienna, Austria§ Department of Palaeontology, University of Vienna, 1090 Vienna, Austria| Institute of Geology and Palaeontology, University of Münster, 48149 Münster, Germany¶ Department of Geobiology, Georg August University, Goldschmidtstraße 3, 37077 Göttingen, Germany
Open Access
Abstract

Amber is chiefly known as a preservational medium ofbiological inclusions, but it is itself a chemofossil, comprised offossilised plant resin. The chemistry of today's resins has been longinvestigated as a means of understanding the botanical sources of ambers.However, little is known about the chemical variability of resins andconsequently about that of the ambers that are derived from particular resins.We undertook experimental resin production in Araucariacean plants toclarify how much natural resin variability is present in two species,Agathis australis and Wollemia nobilis, and whether different resin exudation stimuli types can be chemicallyidentified and differentiated. The latter were tested on the plants, and the resinexudates were collected and investigated with Fourier-transform infrared attenuated total reflection (FTIR-ATR) spectroscopy to givean overview of their chemistry for comparisons, including multivariateanalyses. The Araucariacean resins tested did not show distinct chemicalsignatures linked to a particular resin-inducing treatment. Nonetheless, wedid detect two separate groupings of the treatments for Agathis, in which the branchremoval treatment and mimicked insect-boring treatment-derived resin spectrawere more different from the resin spectra derived from other treatments. Thisappears linked to the lower resin viscosities observed in the branch- andinsect-treatment-derived resins. However the resins, no matter the treatment, couldbe distinguished from both species. The effect of genetic variation was alsoconsidered using the same stimuli on both the seed-grown A. australis derived fromwild-collected populations and on clonally derived W. nobilis plants with naturalminimal genetic diversity. The variability in the resin chemistriescollected did reflect the genetic variability of the source plant. Wesuggest that this natural variability needs to be taken into account whentesting resin and amber chemistries in the future.