scholarly journals Chemical variations in Quercus pollen as a tool for taxonomic identification: implications for long-term ecological and biogeographical research

2019 ◽  
Author(s):  
Florian Muthreich ◽  
Boris Zimmermann ◽  
H. John B. Birks ◽  
Carlos M. Vila-Viçosa ◽  
Alistair W.R Seddon
Keyword(s):  
Phylogenetic Signal ◽  
Pollen Grains ◽  
Taxonomic Resolution ◽  
Fossil Pollen ◽  
Pollen Record ◽  
Least Squares Regression ◽  
Biogeographic Patterns ◽  
Chemical Signatures ◽  
Chemical Variability ◽  
Section Level

vi.AbstractAimFossil pollen is an important tool for understanding biogeographic patterns in the past, but the taxonomic resolution of the fossil-pollen record may be limited to genus or even family level. Chemical analysis of pollen grains has the potential to increase the taxonomic resolution of pollen, but present-day chemical variability is poorly understood. This study aims to investigate whether a phylogenetic signal is present in the chemical variations of Quercus L. pollen and to assess the prospects of chemical techniques for identification in biogeographic research.LocationPortugalTaxonSix taxa (five species, one subspecies) of Quercus L., Q. faginea, Q. robur, Q. robur ssp. estremadurensis, Q. coccifera, Q. rotundifolia and Q. suber belonging to three sections: Cerris, Ilex, and Quercus (Denk, Grimm, Manos, Deng, & Hipp, 2017)MethodsWe collected pollen samples from 297 individual Quercus trees across a 4° (∼450 km) latitudinal gradient and determined chemical differences using Fourier-transform infrared spectroscopy (FTIR). We used canonical powered partial least-squares regression (CPPLS) and discriminant analysis to describe within- and between-species chemical variability.ResultsWe find clear differences in the FTIR spectra from Quercus pollen at the section level (Cerris: ∼98%; Ilex: ∼100%; Quercus: ∼97%). Successful discrimination is based on spectral signals related to lipids and sporopollenins. However, discrimination of species within individual Quercus sections is more difficult: overall, species recall is ∼76% and species misidentifications within sections lie between 18% and 31% of the test-set.Main ConclusionsOur results demonstrate that subgenus level differentiation of Quercus pollen is possible using FTIR methods, with successful classification at the section level. This indicates that operator-independent FTIR approaches can surpass traditional morphological techniques using the light microscope. Our results have implications both for providing new insights into past colonisation pathways of Quercus, and likewise for forecasting future responses to climate change. However, before FTIR techniques can be applied more broadly across palaeoecology and biogeography, our results also highlight a number of research challenges that still need to be addressed, including developing sporopollenin-specific taxonomic discriminators and determining a more complete understanding of the effects of environmental variation on pollen-chemical signatures in Quercus.

scholarly journals Chemotaxonomy of domesticated grasses: a pathway to understanding the origins of agriculture

2019 ◽  
Vol 38 (1) ◽  
pp. 83-95 ◽  
Author(s):  
Phillip E. Jardine ◽  
William D. Gosling ◽  
Barry H. Lomax ◽  
Adele C. M. Julier ◽  
Wesley T. Fraser
Keyword(s):  
Success Rate ◽  
Pollen Grains ◽  
Training Data ◽  
Taxonomic Resolution ◽  
Grass Species ◽  
Pollen Record ◽  
Validation Data ◽  
The Holocene ◽  
Novel Approach ◽  
Leave One Out

Abstract. The grass family (Poaceae) is one of the most economically important plant groups in the world today. In particular many major food crops, including rice, wheat, maize, rye, barley, oats and millet, are grasses that were domesticated from wild progenitors during the Holocene. Archaeological evidence has provided key information on domestication pathways of different grass lineages through time and space. However, the most abundant empirical archive of floral change – the pollen record – has been underused for reconstructing grass domestication patterns because of the challenges of classifying grass pollen grains based on their morphology alone. Here, we test the potential of a novel approach for pollen classification based on the chemical signature of the pollen grains measured using Fourier transform infrared (FTIR) microspectroscopy. We use a dataset of eight domesticated and wild grass species, classified using k-nearest neighbour classification coupled with leave-one-out cross validation. We demonstrate a 95 % classification success rate on training data and an 82 % classification success rate on validation data. This result shows that FTIR spectroscopy can provide enhanced taxonomic resolution enabling species level assignment from pollen. This will enable the full testing of the timing and drivers of domestication and agriculture through the Holocene.

The Early History of the Proteaceae in Australia: the Pollen Record

1998 ◽  
Vol 11 (4) ◽  
pp. 401 ◽  
Author(s):  
Mary E. Dettmann ◽  
David M. Jarzen
Keyword(s):  
Early History ◽  
Taxonomic Resolution ◽  
Fossil Pollen ◽  
Pollen Record ◽  
The Family ◽  
North Eastern ◽  
History Of ◽  
Marked Decline ◽  
Species Groups ◽  
Generic Groups

The early history of the Proteaceae in Australia is traced from the record of fossil pollen that possess characters having taxonomic resolution among extant members of the family. Pollen characters useful for segregating subfamilies and generic groups are apertural number and form together with exine stratification and structure. When considered in conjunction with pollen shape, polarity, and size and exine sculpturing, they may be used to discriminate generic and/or species groups. The fossil pollen record suggests that the family originated in northern Gondwana during the late Cenomanian and radiated by as yet unidentified routes into southern high latitudes during the Turonian. There the family underwent substantial differentiation and expansion during Santonian–Maastrichtian times when at least four of the seven extant subfamilies evolved. Although diversification in Australia principally involved rainforest lineages (e.g. Macadamia–Helicia, Carnarvonia, Gevuina) ancestors of some sclerophyllous taxa (e.g. Adenanthos) also differentiated; this occurred in a regionalised vegetation of mesotherm open-forests in which podocarps and araucarians were important. Subsequent (Paleocene–Eocene) diversification and consolidation of the family may have focused on introduction and expansion of sclerophyllous lineages (e.g. Isopogon, Petrophile), but rainforest elements (e.g. Embothrium) were also involved. The associated vegetation, which was regionalised, experienced considerable floristic modifications during this time with introductions and/or expansion of an array of angiosperm taxa, notably Casuarinaceae, Myrtaceae and Nothofagus. In southern regions a marked decline in proteaceous pollen diversity and abundance occurred near the end of the Eocene, whereas in north-eastern regions the decline may have been later, during the Miocene.

A 1 Ma record of climate-induced vegetation changes using sed aDNA and pollen in a biodiversity hotspot: Lake Towuti, Sulawesi, Indonesia

2021 ◽  
Author(s):  
Akhtar-E Ekram ◽  
Rebecca Hamilton ◽  
Matthew Campbell ◽  
Chloe Plett ◽  
Sureyya Kose ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Carbon Fixation ◽  
Biodiversity Hotspot ◽  
Fossil Pollen ◽  
Vegetation Changes ◽  
Pollen Record ◽  
River Channels ◽  
Sedimentary Record ◽  
Lake Towuti

<p>Several studies have shown that ancient plant-derived DNA can be extracted and sequenced from lake sediments and complement the analysis of fossil pollen in reconstructing past vegetation responses to climate variability and anthropogenic perturbations. The majority of such studies have been performed on Holocene lakes located in cooler higher latitude regions whereas similar studies from tropical lakes are limited. Here, we report a ~1 Ma record of vegetation changes in tropical Lake Towuti (Sulawesi, Indonesia) through parallel pollen and sedimentary ancient DNA (sed aDNA) analysis. Lake Towuti is located in a vegetation biodiversity hotspot and in the centre of the Indo Pacific Warm Pool (IPWP), which comprises the world’s warmest oceanic waters and influences globally important climate systems. In the context of global change, the surface area of the IPWP is rapidly expanding. Lake Towuti is of particular interest since it provides a unique opportunity to obtain a long-term record of IPWP-controlled climate-ecosystem interactions and ecosystem resilience. Stratigraphic analysis of fossil pollen vs. sequencing of preserved chloroplast DNA (cpDNA) signatures (i.e., trnL-P6) both revealed that Lake Towuti experienced significant vegetation changes during the transition from a landscape initially characterized by active river channels, shallow lakes and swamps into a permanent lake ~1 Ma ago. Both proxies marked a predominance of trees or shrubs during most of Lake Towuti’s history, but the trnL-P6 barcoding approach revealed a much higher relative abundance of remote montane conifers, which likely have produced large amounts of chloroplast-rich airborne pollen that were subsequently buried in the sedimentary record. The pollen record showed a higher relative abundance of evergreen tropical forest vegetation, whereas the trnL-P6 record revealed a higher relative abundance of predominantly wetland herbs that must have entered the lake from the local catchment in the form of chloroplast-rich litter. Furthermore, the sedimentary record was rich in presumably wind-derived chloroplast-lacking fern spores, while fern trnL-P6 was only sporadically detected. Only through trnL-P6 barcoding, fern-derived biomass in the sedimentary record could be identified as Schizaeaceae, which is a primitive tropical grass-like fern family often associated with swampy or moist soils. Unlike pollen, trnL-P6 could identify grasses at clade and subfamily levels and confirmed that the majority of grasses in the area represented wet climate C3 grasses or those that can switch between C3 and C4 carbon fixation pathways, whereas grasses that can only perform C4 carbon fixation, indicative of dry climate conditions, were not detected. At least for sediments deposited prior to the Last Glacial Maximum, neither pollen nor trnL-P6 revealed significant vegetation changes between alternating layers of lacustrine green and red sideritic clays thought to have been deposited during orbitally controlled wetter vs. drier periods. These preliminary results suggest that vegetation in this tropical biodiversity hotspot may be relatively resilient to long-term variations in IPWP hydrology.</p>

Phylogeography and ecological niche modelling, coupled with the fossil pollen record, unravel the demographic history of a Neotropical swamp palm through the Quaternary

2014 ◽  
Vol 41 (4) ◽  
pp. 673-686 ◽  
Author(s):  
Natácia Evangelista de Lima ◽  
Matheus S. Lima-Ribeiro ◽  
Carla Faleiro Tinoco ◽  
Levi Carina Terribile ◽  
Rosane G. Collevatti
Keyword(s):  
Ecological Niche ◽  
Demographic History ◽  
Ecological Niche Modelling ◽  
Fossil Pollen ◽  
Pollen Record ◽  
Niche Modelling ◽  
History Of

Identifying pollen grains of Typha latifolia, Typha angustifolia, and Typha ×glauca

2003 ◽  
Vol 81 (9) ◽  
pp. 985-990 ◽  
Author(s):  
Sarah A Finkelstein
Keyword(s):  
Typha Latifolia ◽  
Pollen Grains ◽  
Pollen Record ◽  
Typha Angustifolia ◽  
North American Continent ◽  
Statistical Confidence ◽  
The North ◽  
Pollen Diagrams ◽  
Sparganium Eurycarpum ◽  
Typha Glauca

Typha angustifolia L. and Typha ×glauca Godron have increased their ranges on the North American continent over the past 150 years, and the pollen record has potential to document this spread. In T. angustifolia, pollen disperses as a reticulate, monoporate monad, similar in appearance to the pollen of Sparganium eurycarpum Engelm. Typha angustifolia and Sparganium are generally not distinguished, and T. ×glauca is rarely shown on pollen diagrams. My study of pollen reference material shows that Typha monads and Sparganium can be separated using diameter and roundness at a known level of statistical confidence. Typha monads are on average significantly smaller in diameter (mean and standard deviation = 22.7 ± 2.6 µm) than Sparganium (25.3 ± 2.7 µm). The incidence of angularity is higher in T. angusti folia pollen grains, whereas Sparganium grains are more often rounded. The pollen signature of T. ×glauca consists of mostly monads, but can contain up to 30% dyads, and (or) 14% tetrads, and (or) 10% triads. I suggest that T. angusti folia and T. ×glauca can be identified as one category in the pollen record and, where their dates of arrival are known, this category may be used as a chronostratigraphic indicator.Key words: Typha, Sparganium, pollen, invasive species, wetlands.

Fossil pollen grains of Asteraceae from the Miocene of Patagonia: Nassauviinae affinity

2008 ◽  
Vol 151 (1-2) ◽  
pp. 51-58 ◽  
Author(s):  
Viviana Barreda ◽  
Luis Palazzesi ◽  
María Cristina Tellería
Keyword(s):  
Pollen Grains ◽  
Fossil Pollen

Phylogenetic assessment of pollen characters in Myrtaceae

2012 ◽  
Vol 25 (3) ◽  
pp. 171 ◽  
Author(s):  
Andrew H. Thornhill ◽  
Michael D. Crisp
Keyword(s):  
Internal Transcribed Spacer ◽  
Morphological Characters ◽  
Molecular Dating ◽  
Fossil Pollen ◽  
Pollen Record ◽  
Plant Family ◽  
Pollen Characters ◽  
Pollen Types ◽  
The Relationship ◽  
Potential Use

Identifying synapomorphic morphological characters is needed to select and then accurately place fossils as calibrations on a phylogeny in molecular-dating analyses. The plant family Myrtaceae, with 130 genera and 5500 species, has nine different pollen types, whereas the fossil pollen record of Myrtaceae, represented by the genus Myrtaceidites, putatively extends back to the Cretaceous and also contains at least nine distinct morphospecies. To reveal potential links between extant and fossil pollen, we optimised pollen characters scored from a recent family-wide review of extant Myrtaceae pollen using scanning electron microscopy (SEM) onto a phylogeny of 111 taxa inferred from two chloroplast (matK and ndhF) and one nuclear (internal transcribed spacer, ITS) loci. Our findings indicate the potential use of colpus morphology in diagnosing pollen types in Myrtaceae, whereas the majority of character states of exine pattern, presence of apocolpial island and pollen width appear to be homoplasious. The results of the present study have implications for understanding the relationship between fossil morphospecies and extant Myrtaceae species, and their reliable choice in molecular dating.

Tracing the fossil pollen record of Hedyosmum (Chloranthaceae), an old lineage with recent Neotropical diversification

Grana ◽  
2013 ◽  
Vol 52 (3) ◽  
pp. 161-180 ◽  
Author(s):  
Camila Martínez ◽  
Santiago Madriñán ◽  
Michael Zavada ◽  
Carlos Alberto Jaramillo
Keyword(s):  
Fossil Pollen ◽  
Pollen Record
Sign in / Sign up

Export Citation Format

Share Document