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Publisert 16.09.2015

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Publikasjonsdetaljer

Tidsskrift : PLOS ONE , vol. 10 , onsdag 16. september 2015

Internasjonale standardnummer :
Trykt : 1932-6203
Elektronisk : 1932-6203

Publikasjonstype : Vitenskapelig artikkel

Bidragsytere : Bagcioglu, Murat; Zimmermann, Boris; Kohler, Achim

Sak : 9

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Kjetil Aune
Bibliotekleder
kjetil.aune@nofima.no

Sammendrag

Background
Analysis of pollen grains reveals valuable information on biology, ecology, forensics, climate
change, insect migration, food sources and aeroallergens. Vibrational (infrared and
Raman) spectroscopies offer chemical characterization of pollen via identifiable spectral
features without any sample pretreatment. We have compared the level of chemical information
that can be obtained by different multiscale vibrational spectroscopic techniques.
Methodology
Pollen from 15 different species of Pinales (conifers) were measured by seven infrared and
Raman methodologies. In order to obtain infrared spectra, both reflectance and transmission
measurements were performed on ground and intact pollen grains (bulk measurements),
in addition, infrared spectra were obtained by microspectroscopy of multigrain and
single pollen grain measurements. For Raman microspectroscopy measurements, spectra
were obtained from the same pollen grains by focusing two different substructures of pollen
grain. The spectral data from the seven methodologies were integrated into one data model
by the Consensus Principal Component Analysis, in order to obtain the relations between
the molecular signatures traced by different techniques.
Results
The vibrational spectroscopy enabled biochemical characterization of pollen and detection
of phylogenetic variation. The spectral differences were clearly connected to specific
chemical constituents, such as lipids, carbohydrates, carotenoids and sporopollenins. The
extensive differences between pollen of Cedrus and the rest of Pinaceae family were unambiguously
connected with molecular composition of sporopollenins in pollen grain wall,
while pollen of Picea has apparently higher concentration of carotenoids than the rest of
the family. It is shown that vibrational methodologies have great potential for systematic
collection of data on ecosystems and that the obtained phylogenetic variation can be well
explained by the biochemical composition of pollen. Out of the seven tested methodologies,the best taxonomical differentiation of pollen was obtained by infrared measurements on
bulk samples, as well as by Raman microspectroscopy measurements of the corpus region
of the pollen grain. Raman microspectroscopy measurements indicate that measurement
area, as well as the depth of focus, can have crucial influence on the obtained data.