Studies of Fossil and Modern Spore Wall Biomacromolecules using13C Solid State NMR

Hemsley, Alan R.; Scott, Andrew C.; Barrie, Patrick J.; Chaloner, W. G.

doi:10.1006/anbo.1996.0099

Cited by 71 publications

(37 citation statements)

References 20 publications

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“…In theory acetolysis will remove all cell contents under relatively mild conditions, however, chemically altering the sporopollenin by acetylating free hydroxyl groups (Hemsley et al 1995(Hemsley et al , 1996. Nevertheless, this chemical alteration does not pose analytical problems when using THM-py-techniques, since the strong hydrolysing environment will replace the acetyl group by a methylene moiety analogous to free hydroxyls.…”

Section: Chemistry Of Sporopolleninmentioning

confidence: 95%

“…Still, like the chemical information on fresh spores and pollen, not all research seems to agree on the presence of phenolics in fossil spores and pollen. Oxidative conditions will most likely preferentially degrade the polyphenolics in favour of the aliphatic part as demonstrated by Hemsley et al (1996) using 13 C-NMR on Lycopodium clavatum spores. Diagenetic modelling by heating Pinus sporopollenin furthermore shows that in the early stages the typical polyphenolic signal is replaced by a single aromatic signal, while the aliphatic signal remains.…”

Section: Chemistry Of Sporopolleninmentioning

confidence: 98%

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The occurrence of p-coumaric acid and ferulic acid in fossil plant materials and their use as UV-proxy

et al. 2006

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The applicability of p-coumaric acid and ferulic acid concentrations or ratios in (sub)fossil plant remnant as UV-B proxies relies on various aspects, which are discussed in this paper and will be illustrated with some experimental data. A newly developed THM-micropyrolysis -gas chromatography -mass spectrometry method was tested on various spores, pollen and other plant remains, which were analysed for the presence of the UV-absorbing compounds p-coumaric acid and ferulic acid. This revealed that these supposed building-blocks of sporopollenin appear to be present in pollen of many plant species but also in moss spores. The development of this micropyrolysis method paved the way for the quantitative analysis of UVabsorbing compounds in case only a small amount of analyte is available, for example for fossil pollen and spores but also other small palynomorphs and plant fossils. The use of this technique will provide a better insight in the plant responses to UV-radiation, the chemistry of pollen and spores, their fossil counterparts and furthermore the means for a further development of a proxy for the reconstruction of past UV-B radiation.Abbreviations: pCA -p-coumaric acid; DHP -dehydrogenation polymer; FA -ferulic acid; Fame -fatty acid methyl ester; FTIR -Fourier transform infrared; GC/MS -gas chromatography mass spectrometry; LOD -limit of detection; NMR -nuclear magnetic resonance; py -pyrolysis; SIM -selective ion monitoring; THM -thermally assisted hydrolysis and methylation; TIC -total ion current; TMAHtetramethyl ammonium hydroxide; UV -ultraviolet

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Section: Chemistry Of Sporopolleninmentioning

confidence: 95%

Section: Chemistry Of Sporopolleninmentioning

confidence: 98%

The occurrence of p-coumaric acid and ferulic acid in fossil plant materials and their use as UV-proxy

et al. 2006

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“…With the exception of only a few species, the molecular structure of organic dinoflagellate cysts is poorly known (Hemsley et al, 1994;Kokinos et al, 1998;Versteegh et al, 2007). Nevertheless, some of the previously desctibed OM modification processes, including sulphurisation or oxidative polymerisation of the original cyst wall biomolecule, may be important in its preservation .…”

Section: 3mentioning

confidence: 99%

Selective preservation of organic matter in marine environments; processes and impact on the sedimentary record

et al. 2010

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Abstract. The present paper is the result of a workshop sponsored by the DFG Research Center/Cluster of Excellence MARUM "The Ocean in the Earth System", the International Graduate College EUROPROX, and the Alfred Wegener Institute for Polar and Marine Research. The workshop brought together specialists on organic matter degradation and on proxy-based environmental reconstruction. The paper deals with the main theme of the workshop, understanding the impact of selective degradation/preservation of organic matter (OM) in marine sediments on the interpretation of the fossil record. Special attention is paid to (A) the influence of the molecular composition of OM in relation to the biological and physical depositional environment, including new methods for determining complex organic biomolecules, (B) the impact of selective OM preservation on the interpretation of proxies for marine palaeoceanographic and palaeoclimatic reconstruction, and (C) past marine productivity and selective preservation in sediments.It appears that most of the factors influencing OM preservation have been identified, but many of the mechanisms by which they operate are partly, or even fragmentarily, underCorrespondence to: G. J. M. Versteegh (versteegh@uni-bremen.de) stood. Some factors have not even been taken carefully into consideration. This incomplete understanding of OM breakdown hampers proper assessment of the present and past carbon cycle as well as the interpretation of OM based proxies and proxies affected by OM breakdown.To arrive at better proxy-based reconstructions "deformation functions" are needed, taking into account the transport and diagenesis-related molecular and atomic modifications following proxy formation.Some emerging proxies for OM degradation may shed light on such deformation functions. The use of palynomorph concentrations and selective changes in assemblage composition as models for production and preservation of OM may correct for bias due to selective degradation. Such quantitative assessment of OM degradation may lead to more accurate reconstruction of past productivity and bottom water oxygenation.Given the cost and effort associated with programs to recover sediment cores for paleoclimatological studies, as well as with generating proxy records, it would seem wise to develop a detailed sedimentological and diagenetic context for interpretation of these records. With respect to the latter, parallel acquisition of data that inform on the fidelity of the proxy signatures and reveal potential diagenetic biases would be of clear value.

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“…However, there is currently much less of an understanding of how oxidation affects sporomorph chemistry, and what this means for recovering information on UV-B flux and plant taxonomy from standard palynological preparations, and from fossil sporomorphs that have undergone natural oxidation prior to burial. Previous studies (Hemsley et al, 1996;Rozema et al, 2001a;Blokker et al, 2005) have demonstrated a decline in the concentration of aromatic compounds (including UV-B absorbing phenolic compounds) in sporomorphs following oxidation. However, it is not clear if these chemical changes represent alteration of the exine or simply loss of the protoplasm, intine and outer compounds, or whether different oxidation methods affect sporomorph and sporopollenin chemistry in similar ways, and these questions are yet to be comprehensively addressed in a rigorous experimental framework.…”

mentioning

confidence: 96%

The impact of oxidation on spore and pollen chemistry

Jardine

Fraser

Lomax

et al. 2015

Journal of Micropalaeontology

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Studies of Fossil and Modern Spore Wall Biomacromolecules using13C Solid State NMR

Cited by 71 publications

References 20 publications

The occurrence of p-coumaric acid and ferulic acid in fossil plant materials and their use as UV-proxy

The occurrence of p-coumaric acid and ferulic acid in fossil plant materials and their use as UV-proxy

Selective preservation of organic matter in marine environments; processes and impact on the sedimentary record

The impact of oxidation on spore and pollen chemistry

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