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Coiro M, Roberts EA, Hofmann CC, Seyfullah LJ. Cutting the long branches: Consilience as a path to unearth the evolutionary history of Gnetales. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1082639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Gnetales are one of the most fascinating groups within seed plants. Although the advent of molecular phylogenetics has generated some confidence in their phylogenetic placement of Gnetales within seed plants, their macroevolutionary history still presents many unknowns. Here, we review the reasons for such unknowns, and we focus the discussion on the presence of “long branches” both in their molecular and morphological history. The increased rate of molecular evolution and genome instability as well as the numerous unique traits (both reproductive and vegetative) in the Gnetales have been obstacles to a better understanding of their evolution. Moreover, the fossil record of the Gnetales, though relatively rich, has not yet been properly reviewed and investigated using a phylogenetic framework. Despite these apparent blocks to progress we identify new avenues to enable us to move forward. We suggest that a consilience approach, involving different disciplines such as developmental genetics, paleobotany, molecular phylogenetics, and traditional anatomy and morphology might help to “break” these long branches, leading to a deeper understanding of this mysterious group of plants.
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Klymiuk AA, Rothwell GW, Stockey RA. A novel cupulate seed plant, Xadzigacalix quatsinoensis gen. et sp. nov., provides new insight into the Mesozoic radiation of gymnosperms. AMERICAN JOURNAL OF BOTANY 2022; 109:966-985. [PMID: 35435244 PMCID: PMC9328379 DOI: 10.1002/ajb2.1853] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 06/14/2023]
Abstract
PREMISE Anatomically preserved evidence for a novel clade of gymnosperms emphasizes diversity of seed plants immediately prior to the appearance of angiosperm fossils in the paleontological record. METHODS Cupulate seeds from the Early Cretaceous Apple Bay locality (Vancouver Island) are described from serial cellulose acetate peels and three-dimensional reconstruction. Phylogenetic context is assessed through the comparative analysis of gymnosperm seed producing fructifications and maximum parsimony analysis of a revised morphological data set for seed plant phylogeny. RESULTS Xadzigacalix quatsinoensis gen. et sp. nov. is characterized by an orthotropous ovule with an elongated micropyle and complex integument, enclosed within a radial cupule. The micropylar canal is elongated; and the nucellus extends into the micropyle to seal the post pollination ovule. Except at the apex of the micropyle, the seed is completely enclosed by a parenchymatous cupule with ca. 20 axially elongated secretory ducts. The cupulate seed is produced upon a triangular woody stele, consisting of a parenchymatous pith surrounded by radially aligned tracheids. The stele produces three short terete traces that terminate within the base of the cupule as transfusion tissue at the seed chalaza. CONCLUSIONS Organography, vascularization, nature of the integument and nucellus, and configuration of the micropylar canal distinguish Xadzigacalix quatsinoensis from all other gymnosperm clades. Cladistic analyses suggest the new plant may have affinities with gnetophytes or angiosperms. These results are complemented with a critical re-evaluation of ovulate structures for Mesozoic gymnosperms, providing new insight into plant diversity immediately antecedent to the explosive diversification of flowering plants.
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Affiliation(s)
- Ashley A. Klymiuk
- Department of Biological SciencesUniversity of ManitobaWinnipegManitobaR3T 2N2Canada
- Gantz Family Collections Center, Field Museum, 1400 S Lake Shore DriveChicagoIL60605USA
| | - Gar W. Rothwell
- Department of Botany and Plant PathologyOregon State UniversityCorvallisOR97331−2902USA
- Department of Environmental and Plant Biology317 Porter Hall, Ohio UniversityAthensOH45701USA
| | - Ruth A. Stockey
- Department of Botany and Plant PathologyOregon State UniversityCorvallisOR97331−2902USA
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3
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Leslie AB, Simpson C, Mander L. Reproductive innovations and pulsed rise in plant complexity. Science 2021; 373:1368-1372. [PMID: 34529461 DOI: 10.1126/science.abi6984] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Andrew B Leslie
- Geological Sciences Department, Stanford University, 450 Jane Stanford Way, Building 320, Room 118, Stanford, CA 94305, USA
| | - Carl Simpson
- Geological Sciences, University of Colorado Museum of Natural History, University of Colorado Boulder, Campus Box 265, Boulder, CO 80304, USA
| | - Luke Mander
- School of Environment, Earth and Ecosystem Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
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4
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Moreau JD, Philippe M, Néraudeau D, Dépré E, Le Couls M, Fernandez V, Beurel S. Paleohistology of the Cretaceous resin-producing conifer Geinitzia reichenbachii using X-ray synchrotron microtomography. AMERICAN JOURNAL OF BOTANY 2021; 108:1745-1760. [PMID: 34495546 DOI: 10.1002/ajb2.1722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/05/2021] [Indexed: 06/13/2023]
Abstract
PREMISE The conifer Geinitzia reichenbachii was a common member of the Cretaceous Laurasian floras. However, the histology of G. reichenbachii leafy axes was never described in detail, and our knowledge of its paleoecology remains very limited. Using new and exquisitely preserved silicified material from the Upper Cretaceous of western France, we describe G. reichenbachii from the gross morphology to the cellular scale, then discuss paleoecological and taphonomical implications. METHODS We examined specimens from two localities in western France (Claix and Moragne) using propagation phase-contrast X-ray synchrotron microtomography. RESULTS The cuticle and the inner tissues of leafy axes are preserved in three dimensions. Epidermis, hypodermis, palisade parenchyma, spongy parenchyma, transfusion tracheids, and most of tissues of the vascular cylinder are clearly discernible. The numerous resin ducts are sometimes filled by persisting resin. Additionally, surfaces of some leaves preserved drops and flows of resin. CONCLUSIONS Depositional environmental context combined with histological features of G. reichenbachii suggest that this conifer was adapted to a range of marginal-littoral ecosystems including those open to the sea paleoenvironments and innermost ones influenced by strong continental inputs. Geinitzia reichenbachii was adapted to withstand intense sunlight, hot temperatures coupled with salty sea wind, and dry conditions. The frequent amber-bearing beds in the Cretaceous from western France with Geinitzia as a main component of the associated floras raises the possibility of a role for Geinitzia in the production of the "Charentese amber".
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Affiliation(s)
- Jean-David Moreau
- Biogéosciences, UMR CNRS 6282, Université de Bourgogne Franche-Comté, 6 boulevard Gabriel, Dijon, 21000, France
| | - Marc Philippe
- Université de Lyon, Claude-Bernard Lyon-1, ENTPE, CNRS, UMR 5023 LEHNA, Villeurbanne, 69622, France
| | - Didier Néraudeau
- CNRS UMR 6118 Géosciences, Université Rennes 1, Campus de Beaulieu, 263 avenue du Général Leclerc, Rennes, `Cedex, 35042, France
| | - Eric Dépré
- GIP-GEVES (Groupement d'Étude et de Contrôle des Variétés et Semences), Le Magneraud, Surgères, F-17700, France
| | - Matthieu Le Couls
- CNRS UMR 6118 Géosciences, Université Rennes 1, Campus de Beaulieu, 263 avenue du Général Leclerc, Rennes, `Cedex, 35042, France
| | - Vincent Fernandez
- Imaging and Analysis Centre, Natural History Museum, Cromwell Road, London SW7 5BD, UK
- European Synchrotron Radiation Facility, 7 avenue des Martyrs, Grenoble, 38043, France
| | - Simon Beurel
- CNRS UMR 6118 Géosciences, Université Rennes 1, Campus de Beaulieu, 263 avenue du Général Leclerc, Rennes, `Cedex, 35042, France
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, Berlin, 10115, Germany
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5
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Schopf JW. Precambrian Paleobiology: Precedents, Progress, and Prospects. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.707072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In 1859, C. R. Darwin highlighted the “inexplicable” absence of evidence of life prior to the beginning of the Cambrian. Given this lack of evidence and the natural rather than theological unfolding of life’s development Darwin espoused, over the following 50 years his newly minted theory was disputed. At the turn of the 19th century, beginning with the discoveries of C. D. Walcott, glimmerings of the previously “unknown and unknowable” early fossil record came to light – but Walcott’s Precambrian finds were also discounted. It was not until the breakthrough advances of the 1950’s and the identification of modern stromatolites (1956), Precambrian phytoplankton in shales (1950’s), stromatolitic microbes in cherts (1953), and terminal-Precambrian soft-bodied animal fossils (1950’s) that the field was placed on firm footing. Over the following half-century, the development and application of new analytical techniques coupled with the groundbreaking contributions of the Precambrian Paleobiology Research Group spurred the field to its international and distinctly interdisciplinary status. Significant progress has been made worldwide. Among these advances, the known fossil record has been extended sevenfold (from ∼0.5 to ∼3.5 Ga); the fossil record has been shown consistent with rRNA phylogenies (adding credence to both); and the timing and evolutionary significance of an increase of environmental oxygen (∼2.3 Ga), of eukaryotic organisms (∼2.0 Ga), and of evolution-speeding and biota-diversifying eukaryotic sexual reproduction (∼1.2 Ga) have been identified. Nevertheless, much remains to be learned. Such major unsolved problems include the absence of definitive evidence of the widely assumed life-generating “primordial soup”; the timing of the origin of oxygenic photosynthesis; the veracity of postulated changes in global photic-zone temperature from 3.5 Ga to the present; the bases of the advent of eukaryotic sexuality-requiring gametogenesis and syngamy; and the timing of origin and affinities of the small soft-bodied precursors of the Ediacaran Fauna.
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Atakul-Özdemir A, Warren X, Martin PG, Guizar-Sicairos M, Holler M, Marone F, Martínez-Pérez C, Donoghue PCJ. X-ray nanotomography and electron backscatter diffraction demonstrate the crystalline, heterogeneous and impermeable nature of conodont white matter. ROYAL SOCIETY OPEN SCIENCE 2021; 8:202013. [PMID: 34386244 PMCID: PMC8334826 DOI: 10.1098/rsos.202013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 05/27/2021] [Indexed: 06/13/2023]
Abstract
Conodont elements, microfossil remains of extinct primitive vertebrates, are commonly exploited as mineral archives of ocean chemistry, yielding fundamental insights into the palaeotemperature and chemical composition of past oceans. Geochemical assays have been traditionally focused on the so-called lamellar and white matter crown tissues; however, the porosity and crystallographic nature of the white matter and its inferred permeability are disputed, raising concerns over its suitability as a geochemical archive. Here, we constrain the characteristics of this tissue and address conflicting interpretations using ptychographic X-ray-computed tomography (PXCT), pore network analysis, synchrotron radiation X-ray tomographic microscopy (srXTM) and electron back-scatter diffraction (EBSD). PXCT and pore network analyses based on these data reveal that while white matter is extremely porous, the pores are unconnected, rendering this tissue closed to postmortem fluid percolation. EBSD analyses demonstrate that white matter is crystalline and comprised of a single crystal typically tens of micrometres in dimensions. Combined with evidence that conodont elements grow episodically, these data suggest that white matter, which comprises the denticles of conodont elements, grows syntactically, indicating that individual crystals are time heterogeneous. Together these data provide support for the interpretation of conodont white matter as a closed geochemical system and, therefore, its utility of the conodont fossil record as a historical archive of Palaeozoic and Early Mesozoic ocean chemistry.
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Affiliation(s)
- Ayse Atakul-Özdemir
- Department of Geophysical Engineering, Yuzuncu Yil University, 65180 Van, Turkey
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue Bristol, Bristol BS8 1TQ, UK
| | - Xander Warren
- Interface Analysis Centre, School of Physics, University of Bristol, Bristol BS8 1TL, UK
| | - Peter G. Martin
- Interface Analysis Centre, School of Physics, University of Bristol, Bristol BS8 1TL, UK
| | | | - Mirko Holler
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Federica Marone
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Carlos Martínez-Pérez
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue Bristol, Bristol BS8 1TQ, UK
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, C/Catedrático José Beltrán Martínez no 2, Paterna Valencian 46980, Spain
| | - Philip C. J. Donoghue
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue Bristol, Bristol BS8 1TQ, UK
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Shi G, Herrera F, Herendeen PS, Clark EG, Crane PR. Mesozoic cupules and the origin of the angiosperm second integument. Nature 2021; 594:223-226. [PMID: 34040260 DOI: 10.1038/s41586-021-03598-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 04/30/2021] [Indexed: 11/09/2022]
Abstract
The second integument of the angiosperm ovule is unique among seed plants, with developmental genetics that are distinct from those of the inner integument1. Understanding how the second integument should be compared to structures in other seed plants is therefore crucial to resolving the long-standing question of the origin of angiosperms2-6. Attention has focused on several extinct plants with recurved cupules that are reminiscent of the anatropous organization of the basic bitegmic ovules of angiosperms1-6, but interpretations have been hampered by inadequate information on the relevant fossils. Here we describe abundant exceptionally well-preserved recurved cupules from a newly discovered silicified peat dating to the Early Cretaceous epoch (around 125.6 million years ago) in Inner Mongolia, China. The new material, combined with re-examination of potentially related fossils, indicates that the recurved cupules of several groups of Mesozoic plants are all fundamentally comparable, and that their structure is consistent with the recurved form and development of the second integument in the bitegmic anatropous ovules of angiosperms. Recognition of these angiosperm relatives (angiophytes) provides a partial answer to the question of angiosperm origins, will help to focus future work on seed plant phylogenetics and has important implications for ideas on the origin of the angiosperm carpel.
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Affiliation(s)
- Gongle Shi
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing, China.
| | | | | | | | - Peter R Crane
- Oak Spring Garden Foundation, Upperville, VA, USA.,Yale School of the Environment, Yale University, New Haven, CT, USA
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8
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Rudall PJ. Evolution and patterning of the ovule in seed plants. Biol Rev Camb Philos Soc 2021; 96:943-960. [PMID: 33432779 DOI: 10.1111/brv.12684] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/23/2020] [Accepted: 01/04/2021] [Indexed: 02/06/2023]
Abstract
The ovule and its developmental successor, the seed, together represent a highly characteristic feature of seed plants that has strongly enhanced the reproductive and dispersal potential of this diverse group of taxa. Ovules encompass multiple tissues that perform various roles within a highly constrained space, requiring a complex cascade of genes that generate localized cell proliferation and programmed cell death during different developmental stages. Many heritable morphological differences among lineages reflect relative displacement of these tissues, but others, such as the second (outer) integuments of angiosperms and Gnetales, represent novel and apparently profound and independent innovations. Recent studies, mostly on model taxa, have considerably enhanced our understanding of gene expression in the ovule. However, understanding its evolutionary history requires a comparative and phylogenetic approach that is problematic when comparing extant angiosperms not only with phylogenetically distant extant gymnosperms but also with taxa known only from fossils. This paper reviews ovule characters across a phylogenetically broad range of seed plants in a dynamic developmental context. It discusses both well-established and recent theories of ovule and seed evolution and highlights potential gaps in comparative data that will usefully enhance our understanding of evolutionary transitions and developmental mechanisms.
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Affiliation(s)
- Paula J Rudall
- Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, U.K
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9
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Herrera F, Shi G, Mays C, Ichinnorov N, Takahashi M, Bevitt JJ, Herendeen PS, Crane PR. Reconstructing Krassilovia mongolica supports recognition of a new and unusual group of Mesozoic conifers. PLoS One 2020; 15:e0226779. [PMID: 31940374 PMCID: PMC6961850 DOI: 10.1371/journal.pone.0226779] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 12/03/2019] [Indexed: 11/19/2022] Open
Abstract
Previously unrecognized anatomical features of the cone scales of the enigmatic Early Cretaceous conifer Krassilovia mongolica include the presence of transversely oriented paracytic stomata, which is unusual for all other extinct and extant conifers. Identical stomata are present on co-occurring broad, linear, multiveined leaves assigned to Podozamites harrisii, providing evidence that K. mongolica and P. harrisii are the seed cones and leaves of the same extinct plant. Phylogenetic analyses of the relationships of the reconstructed Krassilovia plant place it in an informal clade that we name the Krassilovia Clade, which also includes Swedenborgia cryptomerioides-Podozamites schenkii, and Cycadocarpidium erdmanni-Podozamites schenkii. All three of these plants have linear leaves that are relatively broad compared to most living conifers, and that are also multiveined with transversely oriented paracytic stomata. We propose that these may be general features of the Krassilovia Clade. Paracytic stomata, and other features of this new group, recall features of extant and fossil Gnetales, raising questions about the phylogenetic homogeneity of the conifer clade similar to those raised by phylogenetic analyses of molecular data.
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Affiliation(s)
- Fabiany Herrera
- Chicago Botanic Garden, Glencoe, Illinois, United States of America
| | - Gongle Shi
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing, People’s Republic of China
| | - Chris Mays
- Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria, Australia
| | - Niiden Ichinnorov
- Institute of Paleontology and Geology, Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
| | - Masamichi Takahashi
- Department of Environmental Sciences, Faculty of Science, Niigata University, Nishi-ku, Niigata, Japan
| | - Joseph J. Bevitt
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, New South Wales, Australia
| | | | - Peter R. Crane
- Oak Spring Garden Foundation, Upperville, Virginia, United States of America
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut, United States of America
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Hesse L, Bunk K, Leupold J, Speck T, Masselter T. Structural and functional imaging of large and opaque plant specimens. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3659-3678. [PMID: 31188449 DOI: 10.1093/jxb/erz186] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/08/2019] [Indexed: 05/20/2023]
Abstract
Three- and four-dimensional imaging techniques are a prerequisite for spatially resolving the form-structure-function relationships in plants. However, choosing the right imaging method is a difficult and time-consuming process as the imaging principles, advantages and limitations, as well as the appropriate fields of application first need to be compared. The present study aims to provide an overview of three imaging methods that allow for imaging opaque, large and thick (>5 mm, up to several centimeters), hierarchically organized plant samples that can have complex geometries. We compare light microscopy of serial thin sections followed by 3D reconstruction (LMTS3D) as an optical imaging technique, micro-computed tomography (µ-CT) based on ionizing radiation, and magnetic resonance imaging (MRI) which uses the natural magnetic properties of a sample for image acquisition. We discuss the most important imaging principles, advantages, and limitations, and suggest fields of application for each imaging technique (LMTS, µ-CT, and MRI) with regard to static (at a given time; 3D) and dynamic (at different time points; quasi 4D) structural and functional plant imaging.
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Affiliation(s)
- Linnea Hesse
- Plant Biomechanics Group and Botanic Garden, University of Freiburg, Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), Freiburg, Germany
| | - Katharina Bunk
- Plant Biomechanics Group and Botanic Garden, University of Freiburg, Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), Freiburg, Germany
| | - Jochen Leupold
- Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Thomas Speck
- Plant Biomechanics Group and Botanic Garden, University of Freiburg, Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), Freiburg, Germany
- Cluster of Excellence livMatS @ FIT - Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Germany
| | - Tom Masselter
- Plant Biomechanics Group and Botanic Garden, University of Freiburg, Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), Freiburg, Germany
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11
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Rudall PJ, Bateman RM. Leaf surface development and the plant fossil record: stomatal patterning in Bennettitales. Biol Rev Camb Philos Soc 2019; 94:1179-1194. [DOI: 10.1111/brv.12497] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 11/28/2022]
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12
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Blomenkemper P, Kerp H, Abu Hamad A, DiMichele WA, Bomfleur B. A hidden cradle of plant evolution in Permian tropical lowlands. Science 2018; 362:1414-1416. [DOI: 10.1126/science.aau4061] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 11/08/2018] [Indexed: 11/02/2022]
Affiliation(s)
- Patrick Blomenkemper
- Palaeobotany Research Group, Institute of Geology and Palaeontology, University of Münster, Münster, Germany
| | - Hans Kerp
- Palaeobotany Research Group, Institute of Geology and Palaeontology, University of Münster, Münster, Germany
| | - Abdalla Abu Hamad
- Department of Applied and Environmental Geology, The University of Jordan, Amman, Jordan
| | | | - Benjamin Bomfleur
- Palaeobotany Research Group, Institute of Geology and Palaeontology, University of Münster, Münster, Germany
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13
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Sokoloff DD, Ignatov MS, Remizowa MV, Nuraliev MS, Blagoderov V, Garbout A, Perkovsky EE. Staminate flower of Prunus s. l. (Rosaceae) from Eocene Rovno amber (Ukraine). JOURNAL OF PLANT RESEARCH 2018; 131:925-943. [PMID: 30032395 DOI: 10.1007/s10265-018-1057-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/09/2018] [Indexed: 06/08/2023]
Abstract
The late Eocene ambers provide plethora of animal and plant fossils including well-preserved angiosperm flowers from the Baltic amber. The Rovno amber from NW Ukraine resembles in many aspects the Baltic amber; however, only fossilized animals and some bryophytes have yet been studied from the Rovno amber. We provide the first detailed description of an angiosperm flower from Rovno amber. The flower is staminate with conspicuous hypanthium, double pentamerous perianth and whorled androecium of 24 stamens much longer than the petals. Sepals are sparsely pubescent and petals are densely hirsute outside. The fossil shares important features with extant members of Prunus subgen. Padus s. l. (incl. Laurocerasus, Pygeum and Maddenia), especially with its evergreen paleotropical species. It is described here as a new species Prunus hirsutipetala D.D.Sokoloff, Remizowa et Nuraliev. Our study provides the first convincing record of fossil flowers of Rosaceae from Eocene of Europe and the earliest fossil flower of Prunus outside North America. Our record of a plant resembling extant tropical species supports palaeoentomological evidences for warm winters in northwestern Ukraine during the late Eocene, as well as suggesting a more significant role of tropical insects in Rovno amber than inferred from Baltic amber.
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Affiliation(s)
- Dmitry D Sokoloff
- Faculty of Biology, M.V. Lomonosov Moscow State University, 1, 12, Leninskie Gory, 119234, Moscow, Russia.
| | - Michael S Ignatov
- Faculty of Biology, M.V. Lomonosov Moscow State University, 1, 12, Leninskie Gory, 119234, Moscow, Russia
- Tsitsin Main Botanical Garden of the Russian Academy of Sciences, Botanicheskaya 4, 127276, Moscow, Russia
| | - Margarita V Remizowa
- Faculty of Biology, M.V. Lomonosov Moscow State University, 1, 12, Leninskie Gory, 119234, Moscow, Russia
| | - Maxim S Nuraliev
- Faculty of Biology, M.V. Lomonosov Moscow State University, 1, 12, Leninskie Gory, 119234, Moscow, Russia
- Joint Russian-Vietnamese Tropical Scientific and Technological Center, Cau Giay, Hanoi, Vietnam
| | | | - Amin Garbout
- Core Research Labs, Natural History Museum, Cromwell Road, London, UK
| | - Evgeny E Perkovsky
- Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, vul.B. Khmelnitskogo, 15, Kiev, 01030, Ukraine
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Sixty-one thousand recent planktonic foraminifera from the Atlantic Ocean. Sci Data 2018; 5:180109. [PMID: 30152812 PMCID: PMC6111889 DOI: 10.1038/sdata.2018.109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 03/22/2018] [Indexed: 12/03/2022] Open
Abstract
Marine microfossils record the environmental, ecological, and evolutionary dynamics of past oceans in temporally expanded sedimentary archives. Rapid imaging approaches provide a means of exploiting the primary advantage of this archive, the vast number of fossils, for evolution and ecology. Here we provide the first large scale image and 2D and 3D shape dataset of modern planktonic foraminifera, a major microfossil group, from 34 Atlantic Ocean sediment samples. Information on more than 124,000 objects is provided, including general object classification for 4/5ths of the dataset (~ 99,000 objects). Of the ~ 99,000 classifications provided, more than 61,000 are complete or damaged planktonic foraminifera. Objects also include benthic foraminifera, ostracods, pteropods, spicules, and planktonic foraminifera test fragments, among others. This dataset is the first major microfossil output of a new high-throughput imaging method (AutoMorph) developed to extract 2D and 3D data from photographic images of fossils. Our sample preparation and imaging techniques are described in detail. The data provided here comprises the most extensive publically available archive of planktonic foraminiferal morphology and morphological variation to date.
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Miano AC, Augusto PED. The Hydration of Grains: A Critical Review from Description of Phenomena to Process Improvements. Compr Rev Food Sci Food Saf 2018; 17:352-370. [DOI: 10.1111/1541-4337.12328] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/28/2017] [Accepted: 11/30/2017] [Indexed: 01/27/2023]
Affiliation(s)
- Alberto Claudio Miano
- Dept. of Agri-food Industry, Food and Nutrition (LAN), Luiz de Queiroz Coll. of Agriculture (ESALQ); Univ. of São Paulo (USP); Piracicaba SP Brazil
| | - Pedro Esteves Duarte Augusto
- Dept. of Agri-food Industry, Food and Nutrition (LAN), Luiz de Queiroz Coll. of Agriculture (ESALQ); Univ. of São Paulo (USP); Piracicaba SP Brazil
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16
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Takahashi M, Herendeen PS, Xiao X. Two early eudicot fossil flowers from the Kamikitaba assemblage (Coniacian, Late Cretaceous) in northeastern Japan. JOURNAL OF PLANT RESEARCH 2017; 130:809-826. [PMID: 28497291 DOI: 10.1007/s10265-017-0945-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 04/03/2017] [Indexed: 06/07/2023]
Abstract
Two new fossil taxa referable to the basal eudicot grade are described from the Kamikitaba locality (ca. 89 MYBP, early Coniacian: Late Cretaceous) of the Futaba Group in Japan. These charcoalified mesofossils exhibit well-preserved three-dimensional structure and were analyzed using synchrotron-radiation X-ray microtomography to document their composition and internal structure. Cathiaria japonica sp. nov. is represented by infructescence segments that consist of an axis bearing three to four fruits. The capsular fruits are sessile and dehiscent and consist of a gynoecium subtended by a bract. No perianth parts are present. The gynoecium is monocarpellate containing two pendulous seeds. The carpel is ascidiate in the lower half and conduplicate in the upper part, and the style is deflected abaxially with a large, obliquely decurrent stigma. Pollen grains are tricolpate with a reticulate exine. The morphological features of Cathiaria are consistent with an assignment to the Buxaceae s. l. (including Didymelaceae). Archaestella verticillatus gen. et sp. nov. is represented by flowers that are small, actinomorphic, pedicellate, bisexual, semi-inferior, and multicarpellate. The floral receptacle is cup shaped with a perigynous perianth consisting of several tepals inserted around the rim. The gynoecium consists of a whorl of ten conduplicate, laterally connate but distally distinct carpels with a conspicuous dorsal bulge, including a central cavity. The styles are short, becoming recurved with a ventrally decurrent stigma. Seeds are ca. 10 per carpel, marginal, pendulous from the broad, oblique summit of the locule. Pollen grains are tricolpate with a reticulate exine pattern, suggesting a relationship to eudicots. The morphological features of Archaestella indicate a possible relationship to Trochodendraceae in the basal grade of eudicots. The fossil currently provides the earliest record of the family and documents the presence of Trochodendraceae in eastern Eurasia during the middle part of the Late Cretaceous.
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Affiliation(s)
- Masamichi Takahashi
- Department of Environmental Sciences, Faculty of Science, Niigata University, Ikarashi, Nishi-ku, Niigata, 950-2181, Japan.
| | | | - Xianghui Xiao
- Advanced Photon Source, 9700 S Cass Avenue, Argonne, IL, 60439, USA
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17
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Bomfleur B, Grimm GW, McLoughlin S. The fossil Osmundales (Royal Ferns)-a phylogenetic network analysis, revised taxonomy, and evolutionary classification of anatomically preserved trunks and rhizomes. PeerJ 2017; 5:e3433. [PMID: 28713650 PMCID: PMC5508817 DOI: 10.7717/peerj.3433] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 05/17/2017] [Indexed: 12/03/2022] Open
Abstract
The Osmundales (Royal Fern order) originated in the late Paleozoic and is the most ancient surviving lineage of leptosporangiate ferns. In contrast to its low diversity today (less than 20 species in six genera), it has the richest fossil record of any extant group of ferns. The structurally preserved trunks and rhizomes alone are referable to more than 100 fossil species that are classified in up to 20 genera, four subfamilies, and two families. This diverse fossil record constitutes an exceptional source of information on the evolutionary history of the group from the Permian to the present. However, inconsistent terminology, varying formats of description, and the general lack of a uniform taxonomic concept renders this wealth of information poorly accessible. To this end, we provide a comprehensive review of the diversity of structural features of osmundalean axes under a standardized, descriptive terminology. A novel morphological character matrix with 45 anatomical characters scored for 15 extant species and for 114 fossil operational units (species or specimens) is analysed using networks in order to establish systematic relationships among fossil and extant Osmundales rooted in axis anatomy. The results lead us to propose an evolutionary classification for fossil Osmundales and a revised, standardized taxonomy for all taxa down to the rank of (sub)genus. We introduce several nomenclatural novelties: (1) a new subfamily Itopsidemoideae (Guaireaceae) is established to contain Itopsidema, Donwelliacaulis, and Tiania; (2) the thamnopteroid genera Zalesskya, Iegosigopteris, and Petcheropteris are all considered synonymous with Thamnopteris; (3) 12 species of Millerocaulis and Ashicaulis are assigned to modern genera (tribe Osmundeae); (4) the hitherto enigmatic Aurealcaulis is identified as an extinct subgenus of Plenasium; and (5) the poorly known Osmundites tuhajkulensis is assigned to Millerocaulis. In addition, we consider Millerocaulis stipabonettiorum a possible member of Palaeosmunda and Millerocaulis estipularis as probably constituting the earliest representative of the (Todea-)Leptopteris lineage (subtribe Todeinae) of modern Osmundoideae.
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Affiliation(s)
- Benjamin Bomfleur
- Institut für Geologie und Paläontologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden
| | - Guido W. Grimm
- Department für Paläontologie, Universität Wien, Wien, Austria
- Orléans, France
| | - Stephen McLoughlin
- Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden
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18
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Herrera F, Shi G, Ichinnorov N, Takahashi M, Bugdaeva EV, Herendeen PS, Crane PR. The presumed ginkgophyte Umaltolepis has seed-bearing structures resembling those of Peltaspermales and Umkomasiales. Proc Natl Acad Sci U S A 2017; 114:E2385-E2391. [PMID: 28265050 PMCID: PMC5373332 DOI: 10.1073/pnas.1621409114] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The origins of the five groups of living seed plants, including the single relictual species Ginkgo biloba, are poorly understood, in large part because of very imperfect knowledge of extinct seed plant diversity. Here we describe well-preserved material from the Early Cretaceous of Mongolia of the previously enigmatic Mesozoic seed plant reproductive structure Umaltolepis, which has been presumed to be a ginkgophyte. Abundant new material shows that Umaltolepis is a seed-bearing cupule that was borne on a stalk at the tip of a short shoot. Each cupule is umbrella-like with a central column that bears a thick, resinous, four-lobed outer covering, which opens from below. Four, pendulous, winged seeds are attached to the upper part of the column and are enclosed by the cupule. Evidence from morphology, anatomy, and field association suggests that the short shoots bore simple, elongate Pseudotorellia leaves that have similar venation and resin ducts to leaves of living GinkgoUmaltolepis seed-bearing structures are very different from those of Ginkgo but very similar to fossils described previously as Vladimaria. Umaltolepis and Vladimaria do not closely resemble the seed-bearing structures of any living or extinct plant, but are comparable in some respects to those of certain Peltaspermales and Umkomasiales (corystosperms). Vegetative similarities of the Umaltolepis plant to Ginkgo, and reproductive similarities to extinct peltasperms and corystosperms, support previous ideas that Ginkgo may be the last survivor of a once highly diverse group of extinct plants, several of which exhibited various degrees of ovule enclosure.
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Affiliation(s)
| | - Gongle Shi
- Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China
| | - Niiden Ichinnorov
- Institute of Paleontology and Geology, Mongolian Academy of Sciences, Ulaanbaatar-51, Mongolia
| | - Masamichi Takahashi
- Department of Environmental Sciences, Faculty of Sciences, Niigata University, Ikarashi, Nishi-ku, Niigata 950-2181, Japan
| | - Eugenia V Bugdaeva
- Institute of Biology and Soil Science, Far East Branch, Russian Academy of Sciences, Vladivostok 690022, Russia
| | | | - Peter R Crane
- School of Forestry and Environmental Studies, Yale University, New Haven, CT 06511;
- Oak Spring Garden Foundation, Oak Spring, Upperville, VA 20184
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Herendeen PS, Friis EM, Pedersen KR, Crane PR. Palaeobotanical redux: revisiting the age of the angiosperms. NATURE PLANTS 2017; 3:17015. [PMID: 28260783 DOI: 10.1038/nplants.2017.15] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/24/2017] [Indexed: 06/06/2023]
Abstract
Angiosperms (flowering plants) are the most diverse of all major lineages of land plants and the dominant autotrophs in most terrestrial ecosystems. Their evolutionary and ecological appearance is therefore of considerable interest and has significant implications for understanding patterns of diversification in other lineages, including insects and other animals. More than half a century ago, influential reviews showed that while angiosperms are richly represented in sediments of Late Cretaceous and younger ages, there are no reliable records of angiosperms from pre-Cretaceous rocks. The extensive new macrofossil, mesofossil, and microfossil data that have accumulated since have confirmed and reinforced this pattern. Recently, however, molecular dating methods have raised the possibility that angiosperms may have existed much earlier, and there have been scattered reports of putative angiosperms from Triassic and Jurassic rocks. Critical assessment of these reports shows that, so far, none provide unequivocal evidence of pre-Cretaceous angiosperms. Angiosperms may ultimately be recognized from Jurassic or earlier rocks, but credible palaeobotanical evidence will require unambiguous documentation of the diagnostic structural features that separate angiosperms from other groups of extant and extinct seed plants.
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Affiliation(s)
| | - Else Marie Friis
- Department of Palaeobiology, Swedish Museum of Natural History, SE-104 05 Stockholm, Sweden
| | | | - Peter R Crane
- Oak Spring Garden Foundation, 1776 Loughborough Lane, Upperville, Virginia 20184, USA
- Yale School of Forestry and Environmental Studies, 195 Prospect Street, New Haven, Connecticut 06511, USA
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20
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Moreau JD, Néraudeau D, Perrichot V, Tafforeau P. 100-million-year-old conifer tissues from the mid-Cretaceous amber of Charente (western France) revealed by synchrotron microtomography. ANNALS OF BOTANY 2017; 119:117-128. [PMID: 27941095 PMCID: PMC5218381 DOI: 10.1093/aob/mcw225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/08/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND AND AIMS Terrestrial plant remains in fossilized tree resin are relatively common. However, histology and preservation of plants entombed in Cretaceous ambers remain poorly known. We report an exquisitely preserved conifer leafy axis from 100-million-year-old opaque amber of western France that is assignable to Glenrosa carentonensis Moreau, Néraudeau, Tafforeau & Dépré. The purpose of this paper is to discuss the taphonomy and the use of microtomography for studies of palaeobotanical remains in amber. METHODS A leafy axis was examined using propagation phase-contrast X-ray synchrotron microtomography with voxel sizes of 14·9, 1·4, and 0·7 μm. KEY RESULTS The conifer leafy axis described is preserved in three dimensions. Despite desiccation of the specimen within the surrounding amber, the cuticle, as well as most of inner tissues, is preserved in three dimensions down to the cellular level. Epidermis, palisade parenchyma, spongy parenchyma, transfusion tracheids and vascular bundles are clearly distinguished. CONCLUSIONS Gross morphology and histology of the specimen were revealed using synchrotron microtomography, allowing an unprecedented resolution for the study of soft-bodied plants entombed in amber. The study reveals a peculiar combination of authigenic and duripartic preservation as well as permineralization, and highlights the complexity of taphonomic processes that can occur in amber inclusions. This fossil demonstrates the difficulty of studying amber-preserved plant remains under certain conditions.
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Affiliation(s)
- Jean-David Moreau
- CNRS UMR 6118 Géosciences Rennes, Université de Rennes 1, Campus de Beaulieu bât. 15, 263 Avenue du Général Leclerc, 35042 Rennes, France
| | - Didier Néraudeau
- CNRS UMR 6118 Géosciences Rennes, Université de Rennes 1, Campus de Beaulieu bât. 15, 263 Avenue du Général Leclerc, 35042 Rennes, France
| | - Vincent Perrichot
- CNRS UMR 6118 Géosciences Rennes, Université de Rennes 1, Campus de Beaulieu bât. 15, 263 Avenue du Général Leclerc, 35042 Rennes, France
| | - Paul Tafforeau
- European Synchrotron Radiation Facility, 71 avenue des Martyrs, 38000 Grenoble, France
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Shi G, Leslie AB, Herendeen PS, Herrera F, Ichinnorov N, Takahashi M, Knopf P, Crane PR. Early Cretaceous Umkomasia from Mongolia: implications for homology of corystosperm cupules. THE NEW PHYTOLOGIST 2016; 210:1418-29. [PMID: 26840646 DOI: 10.1111/nph.13871] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 12/17/2015] [Indexed: 05/21/2023]
Abstract
Corystosperms, a key extinct group of Late Permian to Early Cretaceous plants, are important for understanding seed plant phylogeny, including the evolution of the angiosperm carpel and anatropous bitegmic ovule. Here, we describe a new species of corystosperm seed-bearing organ, Umkomasia mongolica sp. nov., based on hundreds of three-dimensionally preserved mesofossils from the Early Cretaceous of Mongolia. Individual seed-bearing units of U. mongolica consist of a bract subtending an axis that bifurcates, with each fork (cupule stalk) bearing a cupule near the tip. Each cupule is formed by the strongly reflexed cupule stalk and two lateral flaps that partially enclose an erect seed. The seed is borne at, or close to, the tip of the reflexed cupule stalk, with the micropyle oriented towards the stalk base. The corystosperm cupule is generally interpreted as a modified leaf that bears a seed on its abaxial surface. However, U. mongolica suggests that an earlier interpretation, in which the seed is borne directly on an axis (shoot), is equally likely. The 'axial' interpretation suggests a possible relationship of corystosperms to Ginkgo. It also suggests that the cupules of corystosperms may be less distinct from those of Caytonia than has previously been supposed.
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Affiliation(s)
- Gongle Shi
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, 210008, China
- School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, CT, 06511, USA
| | - Andrew B Leslie
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, 02912, USA
| | | | - Fabiany Herrera
- Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL, 60022, USA
| | - Niiden Ichinnorov
- Paleontological Center, Mongolian Academy of Sciences, PO Box 260, Ulaanbaatar-51, Mongolia
| | - Masamichi Takahashi
- Department of Environmental Sciences, Faculty of Sciences, Niigata University, 8050, 2-cho, Ikarashi, Nishi-ku, Niigata, 950-2181, Japan
| | - Patrick Knopf
- Botanischer Garten Rombergpark, Am Rombergpark 49b, Dortmund, 44225, Germany
| | - Peter R Crane
- School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, CT, 06511, USA
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22
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Moreau JD, Néraudeau D, Tafforeau P, Dépré É. Study of the Histology of Leafy Axes and Male Cones of Glenrosa carentonensis sp. nov. (Cenomanian Flints of Charente-Maritime, France) Using Synchrotron Microtomography Linked with Palaeoecology. PLoS One 2015; 10:e0134515. [PMID: 26288019 PMCID: PMC4546065 DOI: 10.1371/journal.pone.0134515] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 07/07/2015] [Indexed: 11/18/2022] Open
Abstract
We report exceptionally well-preserved plant remains ascribed to the extinct conifer Glenrosa J. Watson et H.L. Fisher emend. V. Srinivasan inside silica-rich nodules from the Cenomanian of the Font-de-Benon quarry, Charente-Maritime, western France. Remains are preserved in three dimensions and mainly consist of fragmented leafy axes. Pollen cones of this conifer are for the first time reported and in some cases remain connected to leafy stems. Histology of Glenrosa has not previously been observed; here, most of internal tissues and cells are well-preserved and allow us to describe a new species, Glenrosa carentonensis sp. nov., using propagation phase-contrast X-ray synchrotron microtomography, a non-destructive technique. Leafy axes consist of characteristic helically arranged leaves bearing stomatal crypts. Glenrosa carentonensis sp. nov. differs from the other described species in developing a phyllotaxy 8/21, claw-shaped leaves, a thicker cuticle, a higher number of papillae and stomata per crypt. Pollen cones consist of peltate, helically arranged microsporophylls, each of them bearing 6-7 pollen sacs. The new high resolution tomographic approach tested here allows virtual palaeohistology on plants included inside a dense rock to be made. Most tissues of Glenrosa carentonensis sp. nov. are described. Lithological and palaeontological data combined with xerophytic features of Glenrosa carentonensis sp. nov. suggest that this conifer has been adapted to survive in harsh and instable environments such as coastal area exposed to hot, dry conditions.
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Affiliation(s)
- Jean-David Moreau
- CNRS UMR 6118, Géosciences Rennes, Université Rennes 1, Rennes, France
- Beamline ID19, European Synchrotron Radiation Facility, Grenoble, France
- * E-mail:
| | - Didier Néraudeau
- CNRS UMR 6118, Géosciences Rennes, Université Rennes 1, Rennes, France
| | - Paul Tafforeau
- Beamline ID19, European Synchrotron Radiation Facility, Grenoble, France
| | - Éric Dépré
- GIP-GEVES (Groupement d’Etude et de Contrôle des Variétés et Semences), Surgères, France
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Edwards D, Kenrick P. The early evolution of land plants, from fossils to genomics: a commentary on Lang (1937) 'On the plant-remains from the Downtonian of England and Wales'. Philos Trans R Soc Lond B Biol Sci 2015; 370:20140343. [PMID: 25750238 PMCID: PMC4360123 DOI: 10.1098/rstb.2014.0343] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
During the 1920s, the botanist W. H. Lang set out to collect and investigate some very unpromising fossils of uncertain affinity, which predated the known geological record of life on land. His discoveries led to a landmark publication in 1937, 'On the plant-remains from the Downtonian of England and Wales', in which he revealed a diversity of small fossil organisms of great simplicity that shed light on the nature of the earliest known land plants. These and subsequent discoveries have taken on new relevance as botanists seek to understand the plant genome and the early evolution of fundamental organ systems. Also, our developing knowledge of the composition of early land-based ecosystems and the interactions among their various components is contributing to our understanding of how life on land affects key Earth Systems (e.g. carbon cycle). The emerging paradigm is one of early life on land dominated by microbes, small bryophyte-like organisms and lichens. Collectively called cryptogamic covers, these are comparable with those that dominate certain ecosystems today. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.
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Affiliation(s)
- Dianne Edwards
- School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, UK
| | - Paul Kenrick
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
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Rolletschek H, Fuchs J, Friedel S, Börner A, Todt H, Jakob PM, Borisjuk L. A novel noninvasive procedure for high-throughput screening of major seed traits. PLANT BIOTECHNOLOGY JOURNAL 2015; 13:188-199. [PMID: 25201084 DOI: 10.1111/pbi.12245] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 07/21/2014] [Accepted: 07/27/2014] [Indexed: 06/03/2023]
Abstract
The large numbers of samples processed in breeding and biodiversity programmes require the development of efficient methods for the nondestructive evaluation of basic seed properties. Near-infrared spectroscopy is the state-of-the-art solution for this analytical demand, but it also has some limitations. Here, we present a novel, rapid, accurate procedure based on time domain-nuclear magnetic resonance (TD-NMR), designed to simultaneously quantify a number of basic seed traits without any seed destruction. Using a low-field, benchtop (1) H-NMR instrument, the procedure gives a high-accuracy measurement of oil content (R(2) = 0.98), carbohydrate content (R(2) = 0.99), water content (R(2) = 0.98) and both fresh and dry weight of seeds/grains (R(2) = 0.99). The method requires a minimum of ~20 mg biomass per sample and thus enables to screen individual, intact seeds. When combined with an automated sample delivery system, a throughput of ~1400 samples per day is achievable. The procedure has been trialled as a proof of concept on cereal grains (collection of ~3000 accessions of Avena spp. curated at the IPK genebank). A mathematical multitrait selection approach has been designed to simplify the selection of outlying (most contrasting) accessions. To provide deeper insights into storage oil topology, some oat accessions were further analysed by three-dimensional seed modelling and lipid imaging. We conclude that the novel TD-NMR-based screening tool opens perspectives for breeding and plant biology in general.
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Affiliation(s)
- Hardy Rolletschek
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Gatersleben, Germany
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Mocella V, Brun E, Ferrero C, Delattre D. Revealing letters in rolled Herculaneum papyri by X-ray phase-contrast imaging. Nat Commun 2015; 6:5895. [DOI: 10.1038/ncomms6895] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Accepted: 11/19/2014] [Indexed: 11/09/2022] Open
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26
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Steart DC, Spencer AR, Garwood RJ, Hilton J, Munt MC, Needham J, Kenrick P. X-ray Synchrotron Microtomography of a silicified Jurassic Cheirolepidiaceae (Conifer) cone: histology and morphology of Pararaucaria collinsonae sp. nov. PeerJ 2014; 2:e624. [PMID: 25374776 PMCID: PMC4217189 DOI: 10.7717/peerj.624] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 09/25/2014] [Indexed: 11/20/2022] Open
Abstract
We document a new species of ovulate cone (Pararaucaria collinsonae) on the basis of silicified fossils from the Late Jurassic Purbeck Limestone Group of southern England (Tithonian Stage: ca. 145 million years). Our description principally relies on the anatomy of the ovuliferous scales, revealed through X-ray synchrotron microtomography (SRXMT) performed at the Diamond Light Source (UK). This study represents the first application of SRXMT to macro-scale silicified plant fossils, and demonstrates the significant advantages of this approach, which can resolve cellular structure over lab-based X-ray computed microtomography (XMT). The method enabled us to characterize tissues and precisely demarcate their boundaries, elucidating organ shape, and thus allowing an accurate assessment of affinities. The cones are broadly spherical (ca. 1.3 cm diameter), and are structured around a central axis with helically arranged bract/scale complexes, each of which bares a single ovule. A three-lobed ovuliferous scale and ovules enclosed within pocket-forming tissue, demonstrate an affinity with Cheirolepidiaceae. Details of vascular sclerenchyma bundles, integument structure, and the number and attachment of the ovules indicate greatest similarity to P. patagonica and P. carrii. This fossil develops our understanding of the dominant tree element of the Purbeck Fossil Forest, providing the first evidence for ovulate cheirolepidiaceous cones in Europe. Alongside recent discoveries in North America, this significantly extends the known palaeogeographic range of Pararaucaria, supporting a mid-palaeolatitudinal distribution in both Gondwana and Laurasia during the Late Jurassic. Palaeoclimatic interpretations derived from contemporaneous floras, climate sensitive sediments, and general circulation climate models indicate that Pararaucaria was a constituent of low diversity floras in semi-arid Mediterranean-type environments.
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Affiliation(s)
- David C. Steart
- Department of Earth Sciences, Invertebrates and Plants Division, Natural History Museum, London, United Kingdom
- Department of Agricultural Sciences, LaTrobe University, Melbourne, Victoria, Australia
| | - Alan R.T. Spencer
- Department of Earth Sciences and Engineering, Imperial College London, London, United Kingdom
| | - Russell J. Garwood
- School of Earth, Atmospheric and Environmental Sciences and The Manchester X-ray Imaging Facility, School of Materials, The University of Manchester, Manchester, United Kingdom
| | - Jason Hilton
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Martin C. Munt
- Department of Earth Sciences, Invertebrates and Plants Division, Natural History Museum, London, United Kingdom
| | | | - Paul Kenrick
- Department of Earth Sciences, Invertebrates and Plants Division, Natural History Museum, London, United Kingdom
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Cunningham JA, Rahman IA, Lautenschlager S, Rayfield EJ, Donoghue PCJ. A virtual world of paleontology. Trends Ecol Evol 2014; 29:347-57. [PMID: 24821516 DOI: 10.1016/j.tree.2014.04.004] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 03/26/2014] [Accepted: 04/08/2014] [Indexed: 11/28/2022]
Abstract
Computer-aided visualization and analysis of fossils has revolutionized the study of extinct organisms. Novel techniques allow fossils to be characterized in three dimensions and in unprecedented detail. This has enabled paleontologists to gain important insights into their anatomy, development, and preservation. New protocols allow more objective reconstructions of fossil organisms, including soft tissues, from incomplete remains. The resulting digital reconstructions can be used in functional analyses, rigorously testing long-standing hypotheses regarding the paleobiology of extinct organisms. These approaches are transforming our understanding of long-studied fossil groups, and of the narratives of organismal and ecological evolution that have been built upon them.
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Affiliation(s)
- John A Cunningham
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
| | - Imran A Rahman
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
| | - Stephan Lautenschlager
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
| | - Emily J Rayfield
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK.
| | - Philip C J Donoghue
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK.
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Edwards D, Morris JL, Richardson JB, Kenrick P. Cryptospores and cryptophytes reveal hidden diversity in early land floras. THE NEW PHYTOLOGIST 2014; 202:50-78. [PMID: 24410730 DOI: 10.1111/nph.12645] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/04/2013] [Indexed: 05/18/2023]
Abstract
Cryptospores, recovered from Ordovician through Devonian rocks, differ from trilete spores in possessing distinctive configurations (i.e. hilate monads, dyads, and permanent tetrads). Their affinities are contentious, but knowledge of their relationships is essential to understanding the nature of the earliest land flora. This review brings together evidence about the source plants, mostly obtained from spores extracted from minute, fragmented, yet exceptionally anatomically preserved fossils. We coin the term 'cryptophytes' for plants that produced the cryptospores and show them to have been simple terrestrial organisms of short stature (i.e. millimetres high). Two lineages are currently recognized. Partitatheca shows a combination of characters (e.g. spo-rophyte bifurcation, stomata, and dyads) unknown in plants today. Lenticulatheca encompasses discoidal sporangia containing monads formed from dyads with ultrastructure closer to that of higher plants, as exemplified by Cooksonia. Other emerging groupings are less well characterized, and their precise affinities to living clades remain unclear. Some may be stem group embryophytes or tracheophytes. Others are more closely related to the bryophytes, but they are not bryophytes as defined by extant representatives. Cryptophytes encompass a pool of diversity from which modern bryophytes and vascular plants emerged, but were competitively replaced by early tracheophytes. Sporogenesis always produced either dyads or tetrads, indicating strict genetic control. The long-held consensus that tetrads were the archetypal condition in land plants is challenged.
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Affiliation(s)
- Dianne Edwards
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Jennifer L Morris
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
- Department of Animal and Plant Sciences, Sheffield University, Western Bank, Sheffield, S10 2TN, UK
| | - John B Richardson
- Department of Earth Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Paul Kenrick
- Department of Earth Sciences, Natural History Museum, London, SW7 5BD, UK
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Bomfleur B, McLoughlin S, Vajda V. Fossilized Nuclei and Chromosomes Reveal 180 Million Years of Genomic Stasis in Royal Ferns. Science 2014; 343:1376-7. [DOI: 10.1126/science.1249884] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Moreau JD, Cloetens P, Gomez B, Daviero-Gomez V, Néraudeau D, Lafford TA, Tafforeau P. Multiscale 3D virtual dissections of 100-million-year-old flowers using X-ray synchrotron micro- and nanotomography. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:305-312. [PMID: 24397959 DOI: 10.1017/s1431927613014025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A multiscale approach combining phase-contrast X-ray micro- and nanotomography is applied for imaging a Cretaceous fossil inflorescence in the resolution range from 0.75 μm to 50 nm. The wide range of scale views provides three-dimensional reconstructions from the external gross morphology of the inflorescence fragment to the finest exine sculptures of in situ pollen. This approach enables most of the characteristics usually observed under light microscopy, or with low magnification under scanning and transmission electron microscopy, to be obtained nondestructively. In contrast to previous tomography studies of fossil and extant flowers that used resolutions down to the micron range, we used voxels with a 50 nm side in local tomography scans. This high level of resolution enables systematic affinities of fossil flowers to be established without breaking or slicing specimens.
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Affiliation(s)
- Jean-David Moreau
- Université Rennes 1, CNRS UMR 6118 Géosciences Rennes, Campus de Beaulieu bât. 15, 263 avenue du Général Leclerc, 35042 Rennes, France
| | - Peter Cloetens
- European Synchrotron Radiation Facility, 6, rue J.-Horowitz, BP 220, 38043 Grenoble, France
| | - Bernard Gomez
- Université Lyon 1 (Claude Bernard), CNRS UMR 5276 LGL-TPE, OSU Lyon, Campus La Doua, Bât. Géode, 43 boulevard du 11 Novembre 1918, 69622 Villeurbanne, France
| | - Véronique Daviero-Gomez
- Université Lyon 1 (Claude Bernard), CNRS UMR 5276 LGL-TPE, OSU Lyon, Campus La Doua, Bât. Géode, 43 boulevard du 11 Novembre 1918, 69622 Villeurbanne, France
| | - Didier Néraudeau
- Université Rennes 1, CNRS UMR 6118 Géosciences Rennes, Campus de Beaulieu bât. 15, 263 avenue du Général Leclerc, 35042 Rennes, France
| | - Tamzin A Lafford
- European Synchrotron Radiation Facility, 6, rue J.-Horowitz, BP 220, 38043 Grenoble, France
| | - Paul Tafforeau
- European Synchrotron Radiation Facility, 6, rue J.-Horowitz, BP 220, 38043 Grenoble, France
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Gee CT. Applying microCT and 3D visualization to Jurassic silicified conifer seed cones: A virtual advantage over thin-sectioning. APPLICATIONS IN PLANT SCIENCES 2013; 1:apps.1300039. [PMID: 25202495 PMCID: PMC4103457 DOI: 10.3732/apps.1300039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 10/01/2013] [Indexed: 05/20/2023]
Abstract
UNLABELLED PREMISE OF THE STUDY As an alternative to conventional thin-sectioning, which destroys fossil material, high-resolution X-ray computed tomography (also called microtomography or microCT) integrated with scientific visualization, three-dimensional (3D) image segmentation, size analysis, and computer animation is explored as a nondestructive method of imaging the internal anatomy of 150-million-year-old conifer seed cones from the Late Jurassic Morrison Formation, USA, and of recent and other fossil cones. • METHODS MicroCT was carried out on cones using a General Electric phoenix v|tome|x s 240D, and resulting projections were processed with visualization software to produce image stacks of serial single sections for two-dimensional (2D) visualization, 3D segmented reconstructions with targeted structures in color, and computer animations. • RESULTS If preserved in differing densities, microCT produced images of internal fossil tissues that showed important characters such as seed phyllotaxy or number of seeds per cone scale. Color segmentation of deeply embedded seeds highlighted the arrangement of seeds in spirals. MicroCT of recent cones was even more effective. • CONCLUSIONS This is the first paper on microCT integrated with 3D segmentation and computer animation applied to silicified seed cones, which resulted in excellent 2D serial sections and segmented 3D reconstructions, revealing features requisite to cone identification and understanding of strobilus construction.
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Affiliation(s)
- Carole T. Gee
- Steinmann Institute of Geology, Mineralogy, and Paleontology, Division of Paleontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany
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Staedler YM, Masson D, Schönenberger J. Plant tissues in 3D via X-ray tomography: simple contrasting methods allow high resolution imaging. PLoS One 2013; 8:e75295. [PMID: 24086499 PMCID: PMC3785515 DOI: 10.1371/journal.pone.0075295] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Accepted: 08/14/2013] [Indexed: 11/19/2022] Open
Abstract
Computed tomography remains strongly underused in plant sciences despite its high potential in delivering detailed 3D phenotypical information because of the low X-ray absorption of most plant tissues. Existing protocols to study soft tissues display poor performance, especially when compared to those used on animals. More efficient protocols to study plant material are therefore needed. Flowers of Arabidopsis thaliana and Marcgravia caudata were immersed in a selection of contrasting agents used to treat samples for transmission electron microscopy. Grayscale values for floral tissues and background were measured as a function of time. Contrast was quantified via a contrast index. The thick buds of Marcgravia were scanned to determine which contrasting agents best penetrate thick tissues. The highest contrast increase with cytoplasm-rich tissues was obtained with phosphotungstate, whereas osmium tetroxide and bismuth tatrate displayed the highest contrast increase with vacuolated tissues. Phosphotungstate also displayed the best sample penetration. Furthermore, infiltration with phosphotungstate allowed imaging of all plants parts at a high resolution of 3 µm, which approaches the maximum resolution of our equipment: 1.5 µm. The high affinity of phosphotungstate for vasculature, cytoplasm-rich tissue, and pollen causes these tissues to absorb more X-rays than the surrounding tissues, which, in turn, makes these tissues appear brighter on the scan data. Tissues with different brightness can then be virtually dissected from each other by selecting the bracket of grayscale to be visualized. Promising directions for the future include in silico phenotyping and developmental studies of plant inner parts (e.g., ovules, vasculature, pollen, and cell nuclei) via virtual dissection as well as correlations of quantitative phenotypes with omics datasets. Therefore, this work represents a crucial improvement of previous methods, allowing new directions of research to be undertaken in areas ranging from morphology to systems biology.
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Affiliation(s)
- Yannick M. Staedler
- Department of Structural and Functional Botany, University of Vienna, Vienna, Austria
- * E-mail:
| | - David Masson
- Federal Office of Meteorology and Climatology, MeteoSwiss, Zurich, Switzerland
| | - Jürg Schönenberger
- Department of Structural and Functional Botany, University of Vienna, Vienna, Austria
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Yang Y, Lin L, Wang Q. Chengia laxispicata gen. et sp. nov., a new ephedroid plant from the Early Cretaceous Yixian Formation of western Liaoning, Northeast China: evolutionary, taxonomic, and biogeographic implications. BMC Evol Biol 2013; 13:72. [PMID: 23530702 PMCID: PMC3626868 DOI: 10.1186/1471-2148-13-72] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 03/20/2013] [Indexed: 11/10/2022] Open
Abstract
Background The extant Gnetales include three monotypic families, namely, Ephedraceae (Ephedra), Gnetaceae (Gnetum), and Welwitschiaceae (Welwitschia), all of which possess compound female cones that comprise a main axis and 1 to multiple pairs/whorls of bracts subtending a female reproductive unit or having lower pairs/whorls of bracts sterile. However, the evolutionary origin of such a reproductive architecture in Gnetales is controversial in the light of the competing anthophyte versus gnetifer hypotheses of seed plant relationships. Hence, macrofossils demonstrating the structure of compound female cones of the Gnetales should be important to decipher the early evolution of the order. Results A new ephedroid plant Chengia laxispicata gen. et sp. nov. is described from the Early Cretaceous Yixian Formation of western Liaoning, Northeast China. The fossil represents a part of a leafy shooting system with reproductive organs attached. The main shoot bears internodes and swollen nodes, from which lateral branches arise oppositely. Reproductive organs consist of female spikes terminal to twigs or axillary to linear leaves. Spikes are loosely arranged, having prominent nodes and internodes. Bracts of the spikes are decussately opposite and comprise 4—8 pairs of bracts. Each bract subtends an ellipsoid seed. Seeds are sessile, with a thin outer envelope and a distal micropylar tube. Conclusions Chengia laxispicata gen. et sp. nov. provides a missing link between archetypal fertile organs in the crown lineage of the Gnetales and compound female cones of the extant Ephedraceae. Combined with a wealth of Ephedra and ephedroid macrofossils from the Early Cretaceous, we propose a reduction and sterilization hypothesis that the female cone of the extant Ephedraceae may have stemmed from archetypal fertile organs in the crown lineage of the Gnetales. These have undergone sequentially intermediate links similar to female cones of Cretaceous Siphonospermum, Chengia, and Liaoxia by reduction and sterilization of the lower fertile bracts, shortenings of internodes and peduncles as well as loss of reproductive units in all inferior bracts. The basal family Ephedraceae including Ephedra of the extant Gnetales was demonstrated to have considerable diversity by the Early Cretaceous, so an emended familial diagnosis is given here. The Jehol Biota in Northeast China and adjacent areas contains a plethora of well-preserved macrofossils of Ephedra and ephedroids that show different evolutionary stages including primitive and derived characters of Ephedraceae, so Northeast China and adjacent areas may represent either the centre of origination or one of the centres for early diversification of the family.
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Affiliation(s)
- Yong Yang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, China
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Marton Z, Bhandari HB, Brecher C, Miller SR, Singh B, Nagarkar VV. High efficiency microcolumnar Lu2O3:Eu scintillator thin film for hard X-ray microtomography. ACTA ACUST UNITED AC 2013. [DOI: 10.1088/1742-6596/425/6/062016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Yang Y, Wang Q. The earliest fleshy cone of Ephedra from the early cretaceous Yixian Formation of northeast China. PLoS One 2013; 8:e53652. [PMID: 23341964 PMCID: PMC3544918 DOI: 10.1371/journal.pone.0053652] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 12/03/2012] [Indexed: 12/02/2022] Open
Abstract
Bracts of female cones of extant gymnosperm Ephedra (Joint fir) are either colorful and fleshy (section Ephedra), or dry-winged and membranous (section Alatae), or dry and coriaceous (section Asarca), which have played a crucial role in long-distance seed dispersal that is responsible for a wide distribution of the genus in semiarid and arid areas of Eurasia, North Africa, North America, and South America. Recent molecular systematic studies on Ephedra have suggested that the fleshy bracts in character evolution may be plesiomorphic relative to the dry, membranous and coriaceous bracts. However, little is known about when the fleshy bracts of Ephedra have made their debut in the geological past. Herein, we describe a novel, fleshy bract-bearing female cone macrofossil from the Early Cretaceous (ca. 120—125 Ma) Yixian Formation in Liaoning, northeastern China. This cone bears three ellipsoid seeds subtended by only one whorl of fleshy bracts. Each seed has a thin outer envelope and an inner integument that extends upward and passes through the opening of the outer envelope, forming a thin and straight micropylar tube. Such a syndrome shows the closest similarity to an extant triovulate species Ephedra intermedia in the section Ephedra, but the latter bears a whorl of terminal fertile bracts and more than one whorl of inferior sterile bracts, and a thick outer envelope. Hence, we establish a new fossil species Ephedra carnosa. Our discovery provides the first direct macrofossil evidence for the previous molecular systematics of Ephedra, implying that the origin of fleshy bracts in Ephedra should not have been later than that of the membranous and coriaceous bracts by at least the Early Cretaceous.
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Affiliation(s)
- Yong Yang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, P. R. China
| | - Qi Wang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, P. R. China
- * E-mail:
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36
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Boone MN, Devulder W, Dierick M, Brabant L, Pauwels E, Van Hoorebeke L. Comparison of two single-image phase-retrieval algorithms for in-line x-ray phase-contrast imaging. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2012; 29:2667-2672. [PMID: 23455917 DOI: 10.1364/josaa.29.002667] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The attenuation of x-rays in a material forms the basis of x-ray radiography and tomography. By measuring the transmission of the x-rays over a large amount of raypaths, the three-dimensional (3D) distribution of the x-ray linear attenuation coefficient can be reconstructed in a 3D volume. In x-ray microtomography (μCT), however, the x-ray refraction yields a significant signal in the transmission image and the 3D distribution of the refractive index can be reconstructed in a 3D volume. To do so, several methods exist, on both a hardware and software level. In this paper, we compare two similar software methods, the modified Bronnikov algorithm and the simultaneous phase-and-amplitude retrieval. The first method assumes a pure phase object, whereas the latter assumes a homogeneous object. Although these assumptions seem very restrictive, both methods have proven to yield good results on experimental data.
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Affiliation(s)
- Matthieu N Boone
- Ghent University, Department of Physics and Astronomy Proeftuinstraat 86, Gent B-9000, Belgium.
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Lukeneder A. Computed 3D visualisation of an extinct cephalopod using computer tomographs. COMPUTERS & GEOSCIENCES 2012; 45:68-74. [PMID: 24850976 PMCID: PMC4022087 DOI: 10.1016/j.cageo.2012.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/02/2012] [Accepted: 04/04/2012] [Indexed: 05/09/2023]
Abstract
The first 3D visualisation of a heteromorph cephalopod species from the Southern Alps (Dolomites, northern Italy) is presented. Computed tomography, palaeontological data and 3D reconstructions were included in the production of a movie, which shows a life reconstruction of the extinct organism. This detailed reconstruction is according to the current knowledge of the shape and mode of life as well as habitat of this animal. The results are based on the most complete shell known thus far of the genus Dissimilites. Object-based combined analyses from computed tomography and various computed 3D facility programmes help to understand morphological details as well as their ontogentical changes in fossil material. In this study, an additional goal was to show changes in locomotion during different ontogenetic phases of such fossil, marine shell-bearing animals (ammonoids). Hence, the presented models and tools can serve as starting points for discussions on morphology and locomotion of extinct cephalopods in general, and of the genus Dissimilites in particular. The heteromorph ammonoid genus Dissimilites is interpreted here as an active swimmer of the Tethyan Ocean. This study portrays non-destructive methods of 3D visualisation applied on palaeontological material, starting with computed tomography resulting in animated, high-quality video clips. The here presented 3D geometrical models and animation, which are based on palaeontological material, demonstrate the wide range of applications, analytical techniques and also outline possible limitations of 3D models in earth sciences and palaeontology. The realistic 3D models and motion pictures can easily be shared amongst palaeontologists. Data, images and short clips can be discussed online and, if necessary, adapted in morphological details and motion-style to better represent the cephalopod animal.
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Lu X, Xia Y, Liu M, Qian Y, Zhou X, Gu N, Zhang F. Improved performance of diatomite-based dental nanocomposite ceramics using layer-by-layer assembly. Int J Nanomedicine 2012; 7:2153-64. [PMID: 22619551 PMCID: PMC3356216 DOI: 10.2147/ijn.s29851] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
To fabricate high-strength diatomite-based ceramics for dental applications, the layer-by-layer technique was used to coat diatomite particles with cationic [poly(allylamine hydrochloride)] and anionic [poly(sodium 4-styrenesulfonate)] polymers to improve the dispersion and adsorption of positively charged nano-ZrO(2) (zirconia) as a reinforcing agent. The modified diatomite particles had reduced particle size, narrower size distribution, and were well dispersed, with good adsorption of nano-ZrO(2). To determine the optimum addition levels for nano-ZrO(2), ceramics containing 0, 20, 25, 30, and 35 wt% nano-ZrO(2) were sintered and characterized by the three-point bending test and microhardness test. In addition to scanning electron microscopy, propagation phase-contrast synchrotron X-ray microtomography was used to examine the internal structure of the ceramics. The addition of 30 wt% nano-ZrO(2) resulted in the highest flexural strength and fracture toughness with reduced porosity. Shear bond strength between the core and veneer of our diatomite ceramics and the most widely used dental ceramics were compared; the shear bond strength value for the diatomite-based ceramics was found to be significantly higher than for other groups (P < 0.05). Our results show that diatomite-based nanocomposite ceramics are good potential candidates for ceramic-based dental materials.
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Affiliation(s)
- Xiaoli Lu
- Institute of Stomatology, Nanjing Medical University, Nanjing
- Nantong Stomatological Hospital, Nantong
| | - Yang Xia
- Institute of Stomatology, Nanjing Medical University, Nanjing
| | - Mei Liu
- Institute of Stomatology, Nanjing Medical University, Nanjing
| | - Yunzhu Qian
- Center of Stomatology, The Second Affiliated Hospital of Suzhou University, Suzhou
| | - Xuefeng Zhou
- Suzhou Institute, Southeast University, Suzhou, People’s Republic of China
| | - Ning Gu
- Suzhou Institute, Southeast University, Suzhou, People’s Republic of China
| | - Feimin Zhang
- Institute of Stomatology, Nanjing Medical University, Nanjing
- Suzhou Institute, Southeast University, Suzhou, People’s Republic of China
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Melkus G, Rolletschek H, Fuchs J, Radchuk V, Grafahrend-Belau E, Sreenivasulu N, Rutten T, Weier D, Heinzel N, Schreiber F, Altmann T, Jakob PM, Borisjuk L. Dynamic ¹³C/¹ H NMR imaging uncovers sugar allocation in the living seed. PLANT BIOTECHNOLOGY JOURNAL 2011; 9:1022-37. [PMID: 21535356 DOI: 10.1111/j.1467-7652.2011.00618.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Seed growth and accumulation of storage products relies on the delivery of sucrose from the maternal to the filial tissues. The transport route is hidden inside the seed and has never been visualized in vivo. Our approach, based on high-field nuclear magnetic resonance and a custom made (13)C/(1) H double resonant coil, allows the non-invasive imaging and monitoring of sucrose allocation within the seed. The new technique visualizes the main stream of sucrose and determines its velocity during the grain filling in barley (Hordeum vulgare L.). Quantifiable dynamic images are provided, which allow observing movement of (13)C-sucrose at a sub-millimetre level of resolution. The analysis of genetically modified barley grains (Jekyll transgenic lines, seg8 and Risø13 mutants) demonstrated that sucrose release via the nucellar projection towards the endosperm provides an essential mean for the control of seed growth by maternal organism. The sucrose allocation was further determined by structural and metabolic features of endosperm. Sucrose monitoring was integrated with an in silico flux balance analysis, representing a powerful platform for non-invasive study of seed filling in crops.
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Affiliation(s)
- Gerd Melkus
- Institute of Experimental Physics, University of Würzburg, Am Hubland, Würzburg, Germany
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Mizutani R, Suzuki Y. X-ray microtomography in biology. Micron 2011; 43:104-15. [PMID: 22036251 DOI: 10.1016/j.micron.2011.10.002] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 10/03/2011] [Accepted: 10/03/2011] [Indexed: 10/16/2022]
Abstract
Progress in high-resolution X-ray microtomography has provided us with a practical approach to determining three-dimensional (3D) structures of opaque samples at micrometer to submicrometer resolution. In this review, we give an introduction to hard X-ray microtomography and its application to the visualization of 3D structures of biological soft tissues. Practical aspects of sample preparation, handling, data collection, 3D reconstruction, and structure analysis are described. Furthermore, different sample contrasting methods are approached in detail. Examples of microtomographic studies are overviewed to present an outline of biological applications of X-ray microtomography. We also provide perspectives of biological microtomography as the convergence of sciences in X-ray optics, biology, and structural analysis.
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Affiliation(s)
- Ryuta Mizutani
- Department of Applied Biochemistry, School of Engineering, Tokai University, Kitakaname 4-1-1, Hiratsuka, Kanagawa 259-1292, Japan.
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41
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Endress PK. Angiosperm ovules: diversity, development, evolution. ANNALS OF BOTANY 2011; 107:1465-89. [PMID: 21606056 PMCID: PMC3108811 DOI: 10.1093/aob/mcr120] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 03/29/2011] [Accepted: 04/11/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND Ovules as developmental precursors of seeds are organs of central importance in angiosperm flowers and can be traced back in evolution to the earliest seed plants. Angiosperm ovules are diverse in their position in the ovary, nucellus thickness, number and thickness of integuments, degree and direction of curvature, and histological differentiations. There is a large body of literature on this diversity, and various views on its evolution have been proposed over the course of time. Most recently evo-devo studies have been concentrated on molecular developmental genetics in ovules of model plants. SCOPE The present review provides a synthetic treatment of several aspects of the sporophytic part of ovule diversity, development and evolution, based on extensive research on the vast original literature and on experience from my own comparative studies in a broad range of angiosperm clades. CONCLUSIONS In angiosperms the presence of an outer integument appears to be instrumental for ovule curvature, as indicated from studies on ovule diversity through the major clades of angiosperms, molecular developmental genetics in model species, abnormal ovules in a broad range of angiosperms, and comparison with gymnosperms with curved ovules. Lobation of integuments is not an atavism indicating evolution from telomes, but simply a morphogenetic constraint from the necessity of closure of the micropyle. Ovule shape is partly dependent on locule architecture, which is especially indicated by the occurrence of orthotropous ovules. Some ovule features are even more conservative than earlier assumed and thus of special interest in angiosperm macrosystematics.
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Affiliation(s)
- Peter K Endress
- Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland.
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Rydin C, Friis EM. A new early Cretaceous relative of Gnetales: Siphonospermum simplex gen. et sp. nov. from the Yixian formation of northeast China. BMC Evol Biol 2010; 10:183. [PMID: 20565755 PMCID: PMC2900273 DOI: 10.1186/1471-2148-10-183] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 06/17/2010] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Knowledge on fossil and evolutionary history of the Gnetales has expanded rapidly; Ephedra and ephedroids as well as the Gnetum-Welwitschia clade are now well documented in the Early Cretaceous. However, hypotheses on evolutionary relationships among living and fossil species are hampered by restricted knowledge of morphological variation in living groups and recent studies indicate that gnetalean diversity and character evolution may be more complex than previously assumed and involve additional extinct groups (Bennettitales, Erdtmanithecales and unassigned fossil taxa). RESULTS Here we describe a new fossil related to Gnetales, Siphonospermum simplex from the Early Cretaceous Yixian Formation, an impression/compression of a reproductive shoot. The slender main axis bears one pair of opposite and linear leaves with primary parallel venation. The reproductive units are ovoid, without supporting bracts and borne on one median and two lateral branches. The most conspicuous feature of the fossil is the long, thread-like micropylar tube formed by the integument. Each ovule is surrounded by two different layers representing one or two seed envelopes; an inner sclerenchymatous layer and an outer probably parenchymatous layer. CONCLUSIONS The vegetative and reproductive features of Siphonospermum simplex exclude a relationship to any other group than the Gnetales. A combination of opposite phyllotaxis, linear leaves and ovules surrounded by seed envelope(s) and with a long exposed micropylar tube are known only for extant and extinct Gnetales. Siphonospermum simplex constitutes a new lineage within the Gnetales. Its morphology cannot be directly linked to any previously known plant, but the organization of the reproductive units indicates that it belongs to the Gnetum-Welwitschia clade. Based on the absence of cone bracts and the inferred histology of the seed envelope(s) it could be related to Gnetum, however, there are also affinities with the ephedran lineage, some of which are likely plesiomorphic features, others perhaps not. Phylogeny and character evolution in the Bennettitales, Erdtmanithecales and Gnetales are currently only partly understood and under debate; the exact systematic position of Siphonospermum simplex, i.e., its position within the Gnetales, cannot be resolved with certainty.
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Affiliation(s)
- Catarina Rydin
- University of Zürich, Institute of Systematic Botany, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
| | - Else Marie Friis
- Swedish Museum of Natural History, Department of Palaeobotany, Box 50007, SE-104 05 Stockholm, Sweden
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Abstract
The evolution of the seed represents a remarkable life-history transition for photosynthetic organisms. Here, we review the recent literature and historical understanding of how and why seeds evolved. Answering the 'how' question involves a detailed understanding of the developmental morphology and anatomy of seeds, as well as the genetic programs that determine seed size. We complement this with a special emphasis on the evolution of dormancy, the characteristic of seeds that allows for long 'distance' time travel. Answering the 'why' question involves proposed hypotheses of how natural selection has operated to favor the seed life-history phenomenon. The recent flurry of research describing the comparative biology of seeds is discussed. The review will be divided into sections dealing with: (1) the development and anatomy of seeds; (2) the endosperm; (3) dormancy; (4) early seed-like structures and the transition to seeds; and (5) the evolution of seed size (mass). In many cases, a special distinction is made between angiosperm and gymnosperm seeds. Finally, we make some recommendations for future research in seed biology.
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Affiliation(s)
- Ada Linkies
- Botany/Plant Physiology, Institute for Biology II, Faculty of Biology, University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany (http://www.seedbiology.de)
| | - Kai Graeber
- Botany/Plant Physiology, Institute for Biology II, Faculty of Biology, University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany (http://www.seedbiology.de)
| | - Charles Knight
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, CA 93401, USA
| | - Gerhard Leubner-Metzger
- Botany/Plant Physiology, Institute for Biology II, Faculty of Biology, University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany (http://www.seedbiology.de)
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An uncorrelated relaxed-clock analysis suggests an earlier origin for flowering plants. Proc Natl Acad Sci U S A 2010; 107:5897-902. [PMID: 20304790 DOI: 10.1073/pnas.1001225107] [Citation(s) in RCA: 213] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We present molecular dating analyses for land plants that incorporate 33 fossil calibrations, permit rates of molecular evolution to be uncorrelated across the tree, and take into account uncertainties in phylogenetic relationships and the fossil record. We attached a prior probability to each fossil-based minimum age, and explored the effects of relying on the first appearance of tricolpate pollen grains as a lower bound for the age of eudicots. Many of our divergence-time estimates for major clades coincide well with both the known fossil record and with previous estimates. However, our estimates for the origin of crown-clade angiosperms, which center on the Late Triassic, are considerably older than the unequivocal fossil record of flowering plants or than the molecular dates presented in recent studies. Nevertheless, we argue that our older estimates should be taken into account in studying the causes and consequences of the angiosperm radiation in relation to other major events, including the diversification of holometabolous insects. Although the methods used here do help to correct for lineage-specific heterogeneity in rates of molecular evolution (associated, for example, with evolutionary shifts in life history), we remain concerned that some such effects (e.g., the early radiation of herbaceous clades within angiosperms) may still be biasing our inferences.
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45
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Mathews S, Clements MD, Beilstein MA. A duplicate gene rooting of seed plants and the phylogenetic position of flowering plants. Philos Trans R Soc Lond B Biol Sci 2010; 365:383-95. [PMID: 20047866 PMCID: PMC2838261 DOI: 10.1098/rstb.2009.0233] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Flowering plants represent the most significant branch in the tree of land plants, with respect to the number of extant species, their impact on the shaping of modern ecosystems and their economic importance. However, unlike so many persistent phylogenetic problems that have yielded to insights from DNA sequence data, the mystery surrounding the origin of angiosperms has deepened with the advent and advance of molecular systematics. Strong statistical support for competing hypotheses and recent novel trees from molecular data suggest that the accuracy of current molecular trees requires further testing. Analyses of phytochrome amino acids using a duplicate gene-rooting approach yield trees that unite cycads and angiosperms in a clade that is sister to a clade in which Gingko and Cupressophyta are successive sister taxa to gnetophytes plus Pinaceae. Application of a cycads + angiosperms backbone constraint in analyses of a morphological dataset yields better resolved trees than do analyses in which extant gymnosperms are forced to be monophyletic. The results have implications both for our assessment of uncertainty in trees from sequence data and for our use of molecular constraints as a way to integrate insights from morphological and molecular evidence.
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Affiliation(s)
- Sarah Mathews
- Arnold Arboretum of Harvard University, Cambridge, MA 02138, USA.
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Rydin C, Khodabandeh A, Endress PK. The female reproductive unit of ephedra (Gnetales): comparative morphology and evolutionary perspectives. BOTANICAL JOURNAL OF THE LINNEAN SOCIETY. LINNEAN SOCIETY OF LONDON 2010; 163:387-430. [PMID: 20799438 DOI: 10.1111/j.1095-8339.2010.01066.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Morphological variation in Ephedra (Gnetales) is limited and confusing from an evolutionary perspective, with parallelisms and intraspecific variation. However, recent analyses of molecular data provide a phylogenetic framework for investigations of morphological traits, albeit with few informative characters in the investigated gene regions. We document morphological, anatomical and histological variation patterns in the female reproductive unit and test the hypothesis that some Early Cretaceous fossils, which share synapomorphies with Ephedra, are members of the extant clade. Results indicate that some morphological features are evolutionarily informative although intraspecific variation is evident. Histology and anatomy of cone bracts and seed envelopes show clade-specific variation patterns. There is little evidence for an inclusion of the Cretaceous fossils in the extant clade. Rather, a hypothesized general pattern of reduction of the vasculature in the ephedran seed envelope, probably from four vascular bundles in the fossils, to ancestrally three in the living clade, and later to two, is consistent with phylogenetic and temporal analyses, which indicate that extant diversity evolved after the Cretaceous-Tertiary boundary. Notwithstanding striking similarities between living and Cretaceous Ephedra, available data indicate that the Mesozoic diversity went almost entirely extinct in the late Cretaceous causing a bottleneck effect in Ephedra, still reflected today by an extraordinarily low level of genetic and structural diversity.
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Affiliation(s)
- Catarina Rydin
- Institute of Systematic Botany, University of Zurich, Switzerland
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Specht CD, Bartlett ME. Flower Evolution: The Origin and Subsequent Diversification of the Angiosperm Flower. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2009. [DOI: 10.1146/annurev.ecolsys.110308.120203] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Chelsea D. Specht
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720; ,
| | - Madelaine E. Bartlett
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720; ,
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Complex embryos displaying bilaterian characters from Precambrian Doushantuo phosphate deposits, Weng'an, Guizhou, China. Proc Natl Acad Sci U S A 2009; 106:19056-60. [PMID: 19858483 DOI: 10.1073/pnas.0904805106] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Three-dimensionally preserved embryos from the Precambrian Ediacaran Doushantuo Formation, Weng'an, Guizhou, southern China, have attracted great attention as the oldest fossil evidence yet found for multicellular animal life on Earth. Many embryos are early cleavage embryos and most of them yield a limited phylogenetic signal. Here we report the discovery of two Doushantuo embryos that are three-dimensionally preserved and complex. Imaging techniques using propagation phase-contrast based synchrotron radiation microtomography (PPC-SR-microCT) reveal that the organization of cells demonstrates several bilaterian features, including the formation of anterior-posterior, dorso-ventral, and right-left polarities, and cell differentiation. Unexpectedly, our observations show a noticeable difference in organization patterns between the embryos, suggesting that they represent two distinct taxa. These embryos provide further evidence for the presence of bilaterian animals in the Doushantuo biota. Furthermore, these bilaterians had already diverged into distantly related groups at least 40 million years before the Cambrian radiation, indicating that the last common ancestor of the bilaterians lived much earlier than is usually thought.
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Virtual taphonomy using synchrotron tomographic microscopy reveals cryptic features and internal structure of modern and fossil plants. Proc Natl Acad Sci U S A 2009; 106:12013-8. [PMID: 19574457 DOI: 10.1073/pnas.0901468106] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
While more commonly applied in zoology, synchrotron radiation X-ray tomographic microscopy (SRXTM) is well-suited to nondestructive study of the morphology and anatomy of both fossil and modern plants. SRXTM uses hard X-rays and a monochromatic light source to provide high-resolution data with little beam-hardening, resulting in slice data with clear boundaries between materials. Anatomy is readily visualized, including various planes of section from a single specimen, as clear as in traditional histological sectioning at low magnifications. Thus, digital sectioning of rare or difficult material is possible. Differential X-ray attenuation allows visualization of different layers or chemistries to enable virtual 3-dimensional (3D) dissections of material. Virtual potential fossils can be visualized and digital tissue removal reveals cryptic underlying morphology. This is essential for fossil identification and for comparisons between assemblages where fossils are preserved by different means. SRXTM is a powerful approach for botanical studies using morphology and anatomy. The ability to gain search images in both 2D and 3D for potential fossils gives paleobotanists a tool--virtual taphonomy--to improve our understanding of plant evolution and paleobiogeography.
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