Molecular signatures of fossil leaves provide unexpected new evidence for extinct plant relationships

Vajda, Vivi; Pučetaitė, Milda; McLoughlin, Stephen; Engdahl, Anders; Heimdal, Jimmy; Uvdal, Per

doi:10.1038/s41559-017-0224-5

Cited by 31 publications

(23 citation statements)

References 49 publications

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“…Perhaps most significantly, groups such as the Cycadales, ginkgophytes, and Bennettitales are generally well represented in macrofloral records from the Jurassic (e.g. Spicer and Hill 1979;Pole 2001Pole , 2009Popa 2014;Pott and McLoughlin 2014;Vajda et al 2017;McLoughlin et al 2018, this issue). However, such groups typically produce simple monosulcate pollen (e.g.…”

Section: Comparison Between the Palynoflora And Macrofloramentioning

confidence: 99%

Palynology of Jurassic (Bathonian) sediments from Donbas, northeast Ukraine

Shevchuk

Slater

Vajda

2018

Palaeobio Palaeoenv

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A palynological and sedimentological study of an outcrop succession adjacent to the village of Kamyanka within the Kharkiv region of northeast Ukraine was carried out. The successions occur within the Dnieper-Donets Basin, which hosts vast successions (> 20 km) of post midDevonian strata and is one of the main hydrocarbonproducing basins in Europe. Middle Jurassic sandstones, siltstones and claystones represent the sedimentary successions at the Kamyanska locality. Few palynological studies have been performed on the Jurassic of Ukraine and even fewer presented in the international literature. Thirty spore taxa and 21 pollen taxa were identified, together with taxa kept in open nomenclature (e.g. bisaccate pollen). Two palynological assemblages were identified within the Kamyanska succession (assemblages A and B) dated as Bathonian. Assemblage A is dominated by the fern spores (Cyathidites and Osmundacidites) and gymnosperm pollen produced by Cupressaceae (Perinopollenites elatoides), ginkgophytes/Cycadales/ Bennettitales (monosulcates) and Cheirolepidiaceae (Classopollis). Assemblage B differs in also comprising high abundances of Gleicheniidites and higher percentages of Pinuspollenites and Araucariacites compared to assemblage A. Another difference between the two units is the high relative abundance of seed fern pollen (Alisporites) in the upper part of assemblage B. The thermal alteration index (TAI) of the palynomorphs is estimated to range from 3 to 3.5, indicating a burial depth corresponding to the mature main phase of liquid petroleum and, to some extent, gas generation. Comparisons between the miospore and macrofloral assemblages show that the palynoflora and macroflora are strongly similar at broad taxonomic levels. Importantly, the miospore assemblages described here compare well with European Middle Jurassic assemblages indicating limited provincialism, with similar vegetation extending from eastern Ukraine and across most of Western Europe.Keywords Mesozoic . Kamyanka . Petroleum . Vegetation . Thermal alteration index (TAI) . Dnieper-Donets Basin ІntroductionThe Jurassic is an interesting period in the Earth's history as it saw the rise to ecological dominance of the dinosaurs, the evolution of birds, extant sub-classes of mammals, the fragmentation of Pangea and two major flood basalt events, both associated with massive biotic change. This took place in a context of generally elevated CO 2 and muted latitudinal temperature gradients; i.e. temperature differences between the tropics and the polar regions were less extreme compared to the present (Steinthorsdottir and Vajda 2015; Slater et al. 2018a, this issue). The poles were ice-free, and the vegetation was characterised by little provincialism (Vajda and WigforssLange 2009). However, in order to compare and contrast the vegetation between different regions through the palynoflora,

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Section: Comparison Between the Palynoflora And Macrofloramentioning

confidence: 99%

Palynology of Jurassic (Bathonian) sediments from Donbas, northeast Ukraine

Shevchuk

Slater

Vajda

2018

Palaeobio Palaeoenv

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“…2010), and with fossil cuticle fragments with ambiguous phylogenetic relationships (Vajda et al . 2017). Therefore, as long as a taxonomic signature is still present in deep time sporopollenin (or cuticular material), there is potential to use it for classification purposes even if it is modified from its original state.…”

Section: Discussionmentioning

confidence: 99%

Sporopollenin chemistry and its durability in the geological record: an integration of extant and fossil chemical data across the seed plants

et al. 2021

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Sporopollenin is a highly resistant biopolymer that forms the outer wall of pollen and spores (sporomorphs). Recent research into sporopollenin chemistry has opened up a range of new avenues for palynological research, including chemotaxonomic classification of morphologically cryptic taxa. However, there have been limited attempts to directly integrate extant and fossil sporopollenin chemical data. Of particular importance is the impact of sample processing to isolate sporopollenin from fresh sporomorphs, and the extent of chemical changes that occur once sporomorphs enter the geological record. Here, we explore these issues using Fourier transform infrared (FTIR) microspectroscopy data from extant and fossil grass, Nitraria (a steppe plant), and conifer pollen. We show a 98% classification success rate at subfamily level with extant grass pollen, demonstrating a strong taxonomic signature in isolated sporopollenin. However, we also reveal substantial chemical differences between extant and fossil sporopollenin, which can be tied to both early diagenetic changes acting on the sporomorphs and chemical derivates of sample processing. Our results demonstrate that directly integrating extant and late Quaternary chemical data should be tractable as long as comparable sample processing routines are maintained. Consistent differences between extant and deeper time sporomorphs, however, suggests that classifying fossil specimens using extant training sets will be challenging. Further work is therefore required to understand and simulate the effects of diagenetic processes on sporopollenin chemistry.

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“…Analysis using FTIR and ATR is commonly used on both living and fossil plants showing that complex biomolecules survive and are identifiable in the fossil record [26][27][28] . FTIR analyses compare living and fossil resin and gum samples ( Supplementary Fig.…”

Section: Spectroscopymentioning

confidence: 99%

Cretaceous gnetalean yields first preserved plant gum

Roberts

Seyfullah

Loveridge

et al. 2020

Sci Rep

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Some liquid plant exudates (e.g. resin) can be found preserved in the fossil record. However, due to their high solubility, gums have been assumed to dissolve before fossilisation. The visual appearance of gums (water-soluble polysaccharides) is so similar to other plant exudates, particularly resin, that chemical testing is essential to differentiate them. Remarkably, Welwitschiophyllum leaves from early Cretaceous, Brazil provide the first chemical confirmation of a preserved gum. This is despite the leaves being exposed to water twice during formation and subsequent weathering of the crato formation. the Welwitschiophyllum plant shares the presence of gum ducts inside leaves with its presumed extant relative the gnetalean Welwitschia. This fossil gum presents a chemical signature remarkably similar to the gum in extant Welwitschia and is distinct from those of fossil resins. We show for the first time that a water-soluble plant exudate has been preserved in the fossil record, potentially allowing us to recognise further biomolecules thought to be lost during the fossilisation process. A wide variety of vascular plants produce fluid exudates 1 e.g. resins and gums, with each group differing in chemical definitions (Table 1). Due to similarity in physical appearance distinguishing exudates based on chemistry is vital, for example gums and resins are visually similar resulting in these terms being used interchangeably 1. However, their chemical definitions are very different (Table 1); resins are composed of lipid-soluble terpenoids 1,2 , while gums are complex, highly branched (non-starch) water-soluble polysaccharides 3. A common example of this misunderstanding is the Eucalyptus tree, which is known as a gum tree, but nuclear magnetic resonance analysis of the Eucalyptus exudate shows its composition to be polyphenolic and is therefore actually a kino 4 (Table 1). Differences between gum and resin can also be seen in the functional roles within the plant. The main roles of resins are to respond to wounding, as a defence against pathogens and to dissuade herbivory by insects and other organisms 2,5,6. Gum is involved in food storage, structural support, and also for wound sealing, but there is no common role across taxa 3. Further confusion arises as some plants, e.g. Boswellia and Commiphora species, even produce exudates with a mixture of polysaccharide and resin components (the gum resins myrrh and frankincense respectively) 1. Until now only fossilised plant resin (ambers) 7 and latex filaments have been reported preserved in the fossil record 8,9. While the fossilisation of fluid exudates might seem unlikely, the fossilisation of resin is relatively common, and extends back some 320 million years to the Carboniferous 10 , but chemically confirmed gums have never been reported. The Early Cretaceous (~120 million year old) Crato Formation 11 of northeast Brazil (Supplementary Fig. S1) is a well-known laminated limestone deposit that yields exceptionally preserved vertebrates, arthropods, and plants from the ...

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Molecular signatures of fossil leaves provide unexpected new evidence for extinct plant relationships

Cited by 31 publications

References 49 publications

Palynology of Jurassic (Bathonian) sediments from Donbas, northeast Ukraine

Palynology of Jurassic (Bathonian) sediments from Donbas, northeast Ukraine

Sporopollenin chemistry and its durability in the geological record: an integration of extant and fossil chemical data across the seed plants

Cretaceous gnetalean yields first preserved plant gum

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