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McElwain JC, Matthaeus WJ, Barbosa C, Chondrogiannis C, O' Dea K, Jackson B, Knetge AB, Kwasniewska K, Nair R, White JD, Wilson JP, Montañez IP, Buckley YM, Belcher CM, Nogué S. Functional traits of fossil plants. THE NEW PHYTOLOGIST 2024; 242:392-423. [PMID: 38409806 DOI: 10.1111/nph.19622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 12/19/2023] [Indexed: 02/28/2024]
Abstract
A minuscule fraction of the Earth's paleobiological diversity is preserved in the geological record as fossils. What plant remnants have withstood taphonomic filtering, fragmentation, and alteration in their journey to become part of the fossil record provide unique information on how plants functioned in paleo-ecosystems through their traits. Plant traits are measurable morphological, anatomical, physiological, biochemical, or phenological characteristics that potentially affect their environment and fitness. Here, we review the rich literature of paleobotany, through the lens of contemporary trait-based ecology, to evaluate which well-established extant plant traits hold the greatest promise for application to fossils. In particular, we focus on fossil plant functional traits, those measurable properties of leaf, stem, reproductive, or whole plant fossils that offer insights into the functioning of the plant when alive. The limitations of a trait-based approach in paleobotany are considerable. However, in our critical assessment of over 30 extant traits we present an initial, semi-quantitative ranking of 26 paleo-functional traits based on taphonomic and methodological criteria on the potential of those traits to impact Earth system processes, and for that impact to be quantifiable. We demonstrate how valuable inferences on paleo-ecosystem processes (pollination biology, herbivory), past nutrient cycles, paleobiogeography, paleo-demography (life history), and Earth system history can be derived through the application of paleo-functional traits to fossil plants.
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Affiliation(s)
- Jennifer C McElwain
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - William J Matthaeus
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Catarina Barbosa
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | | | - Katie O' Dea
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Bea Jackson
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Antonietta B Knetge
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Kamila Kwasniewska
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Richard Nair
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Joseph D White
- Department of Biology, Baylor University, Waco, 76798-7388, TX, USA
| | - Jonathan P Wilson
- Department of Environmental Studies, Haverford College, Haverford, Pennsylvania, 19041, PA, USA
| | - Isabel P Montañez
- UC Davis Institute of the Environment, University of California, Davis, CA, 95616, USA
- Department of Earth and Planetary Sciences, University of California, Davis, CA, 95616, USA
| | - Yvonne M Buckley
- School of Natural Sciences, Zoology, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | | | - Sandra Nogué
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), 08193, Catalonia, Spain
- CREAF, Bellaterra (Cerdanyola del Vallès), 08193, Catalonia, Spain
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Bouda M, Huggett BA, Prats KA, Wason JW, Wilson JP, Brodersen CR. Hydraulic failure as a primary driver of xylem network evolution in early vascular plants. Science 2022; 378:642-646. [DOI: 10.1126/science.add2910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The earliest vascular plants had stems with a central cylindrical strand of water-conducting xylem, which rapidly diversified into more complex shapes. This diversification is understood to coincide with increases in plant body size and branching; however, no selection pressure favoring xylem strand-shape complexity is known. We show that incremental changes in xylem network organization that diverge from the cylindrical ancestral form lead to progressively greater drought resistance by reducing the risk of hydraulic failure. As xylem strand complexity increases, independent pathways for embolism spread become fewer and increasingly concentrated in more centrally located conduits, thus limiting the systemic spread of embolism during drought. Selection by drought may thus explain observed trajectories of xylem strand evolution in the fossil record and the diversity of extant forms.
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Affiliation(s)
- Martin Bouda
- Institute of Botany, Czech Academy of Sciences, Průhonice, Czechia
| | | | - Kyra A. Prats
- Yale School of the Environment, New Haven, CT, USA
- New York Botanical Garden, Bronx, NY, USA
| | - Jay W. Wason
- School of Forest Resources, University of Maine, Orono, ME, USA
| | - Jonathan P. Wilson
- Department of Environmental Studies, Haverford College, Haverford, PA, USA
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Freeze tolerance influenced forest cover and hydrology during the Pennsylvanian. Proc Natl Acad Sci U S A 2021; 118:2025227118. [PMID: 34635589 DOI: 10.1073/pnas.2025227118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2021] [Indexed: 11/18/2022] Open
Abstract
The distribution of forest cover alters Earth surface mass and energy exchange and is controlled by physiology, which determines plant environmental limits. Ancient plant physiology, therefore, likely affected vegetation-climate feedbacks. We combine climate modeling and ecosystem-process modeling to simulate arboreal vegetation in the late Paleozoic ice age. Using GENESIS V3 global climate model simulations, varying pCO2, pO2, and ice extent for the Pennsylvanian, and fossil-derived leaf C:N, maximum stomatal conductance, and specific conductivity for several major Carboniferous plant groups, we simulated global ecosystem processes at a 2° resolution with Paleo-BGC. Based on leaf water constraints, Pangaea could have supported widespread arboreal plant growth and forest cover. However, these models do not account for the impacts of freezing on plants. According to our interpretation, freezing would have affected plants in 59% of unglaciated land during peak glacial periods and 73% during interglacials, when more high-latitude land was unglaciated. Comparing forest cover, minimum temperatures, and paleo-locations of Pennsylvanian-aged plant fossils from the Paleobiology Database supports restriction of forest extent due to freezing. Many genera were limited to unglaciated land where temperatures remained above -4 °C. Freeze-intolerance of Pennsylvanian arboreal vegetation had the potential to alter surface runoff, silicate weathering, CO2 levels, and climate forcing. As a bounding case, we assume total plant mortality at -4 °C and estimate that contracting forest cover increased net global surface runoff by up to 6.1%. Repeated freezing likely influenced freeze- and drought-tolerance evolution in lineages like the coniferophytes, which became increasingly dominant in the Permian and early Mesozoic.
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Wilson JP, White JD, Montañez IP, DiMichele WA, McElwain JC, Poulsen CJ, Hren MT. Carboniferous plant physiology breaks the mold. THE NEW PHYTOLOGIST 2020; 227:667-679. [PMID: 32267976 DOI: 10.1111/nph.16460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 11/17/2019] [Indexed: 06/11/2023]
Abstract
How plants have shaped Earth surface feedbacks over geologic time is a key question in botanical and geological inquiry. Recent work has suggested that biomes during the Carboniferous Period contained plants with extraordinary physiological capacity to shape their environment, contradicting the previously dominant view that plants only began to actively moderate the Earth's surface with the rise of angiosperms during the Mesozoic Era. A recently published Viewpoint disputes this recent work, thus here, we document in detail, the mechanistic underpinnings of our modeling and illustrate the extraordinary ecophysiological nature of Carboniferous plants.
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Affiliation(s)
- Jonathan P Wilson
- Department of Environmental Studies, Haverford College, Haverford, PA, 19041, USA
| | - Joseph D White
- Department of Biology, Baylor University, Waco, TX, 76798, USA
| | - Isabel P Montañez
- Department of Earth and Planetary Sciences, University of California, Davis, CA, 95616, USA
| | - William A DiMichele
- Department of Paleobiology, Smithsonian Museum of Natural History, Washington, DC, 20560, USA
| | - Jennifer C McElwain
- Department of Botany, School of Natural Sciences, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland
| | - Christopher J Poulsen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Michael T Hren
- Center for Integrative Geosciences, University of Connecticut, Storrs, CT, 06269, USA
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Vuosku J, Karppinen K, Muilu-Mäkelä R, Kusano T, Sagor GHM, Avia K, Alakärppä E, Kestilä J, Suokas M, Nickolov K, Hamberg L, Savolainen O, Häggman H, Sarjala T. Scots pine aminopropyltransferases shed new light on evolution of the polyamine biosynthesis pathway in seed plants. ANNALS OF BOTANY 2018; 121:1243-1256. [PMID: 29462244 PMCID: PMC5946884 DOI: 10.1093/aob/mcy012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 04/18/2018] [Indexed: 05/21/2023]
Abstract
Background and Aims Polyamines are small metabolites present in all living cells and play fundamental roles in numerous physiological events in plants. The aminopropyltransferases (APTs), spermidine synthase (SPDS), spermine synthase (SPMS) and thermospermine synthase (ACL5), are essential enzymes in the polyamine biosynthesis pathway. In angiosperms, SPMS has evolved from SPDS via gene duplication, whereas in gymnosperms APTs are mostly unexplored and no SPMS gene has been reported. The present study aimed to investigate the functional properties of the SPDS and ACL5 proteins of Scots pine (Pinus sylvestris L.) in order to elucidate the role and evolution of APTs in higher plants. Methods Germinating Scots pine seeds and seedlings were analysed for polyamines by high-performance liquid chromatography (HPLC) and the expression of PsSPDS and PsACL5 genes by in situ hybridization. Recombinant proteins of PsSPDS and PsACL5 were produced and investigated for functional properties. Also gene structures, promoter regions and phylogenetic relationships of PsSPDS and PsACL5 genes were analysed. Key Results Scots pine tissues were found to contain spermidine, spermine and thermospermine. PsSPDS enzyme catalysed synthesis of both spermidine and spermine. PsACL5 was found to produce thermospermine, and PsACL5 gene expression was localized in the developing procambium in embryos and tracheary elements in seedlings. Conclusions Contrary to previous views, our results demonstrate that SPMS activity is not a novel feature developed solely in the angiosperm lineage of seed plants but also exists as a secondary property in the Scots pine SPDS enzyme. The discovery of bifunctional SPDS from an evolutionarily old conifer reveals the missing link in the evolution of the polyamine biosynthesis pathway. The finding emphasizes the importance of pre-existing secondary functions in the evolution of new enzyme activities via gene duplication. Our results also associate PsACL5 with the development of vascular structures in Scots pine.
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Affiliation(s)
- Jaana Vuosku
- University of Oulu, Department of Ecology and Genetics, Oulu, Finland
| | - Katja Karppinen
- University of Oulu, Department of Ecology and Genetics, Oulu, Finland
| | - Riina Muilu-Mäkelä
- Natural Resources Institute Finland, Bio-based Business and Industry, Parkano, Finland
| | - Tomonobu Kusano
- Tohoku University, Graduate School of Life Sciences, Sendai, Miyagi, Japan
| | - G H M Sagor
- Tohoku University, Graduate School of Life Sciences, Sendai, Miyagi, Japan
| | - Komlan Avia
- University of Oulu, Department of Ecology and Genetics, Oulu, Finland
- UMI 3614 Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Universités, UPMC, Pontificia Universidad Católica de Chile, Universidad Austral de Chile, Station Biologique Roscoff, Roscoff, France
| | - Emmi Alakärppä
- University of Oulu, Department of Ecology and Genetics, Oulu, Finland
| | - Johanna Kestilä
- University of Oulu, Department of Ecology and Genetics, Oulu, Finland
| | - Marko Suokas
- University of Oulu, Department of Ecology and Genetics, Oulu, Finland
| | - Kaloian Nickolov
- University of Oulu, Department of Ecology and Genetics, Oulu, Finland
| | - Leena Hamberg
- Natural Resources Institute Finland, Management and Production of Renewable Resources, Vantaa, Finland
| | - Outi Savolainen
- University of Oulu, Department of Ecology and Genetics, Oulu, Finland
| | - Hely Häggman
- University of Oulu, Department of Ecology and Genetics, Oulu, Finland
| | - Tytti Sarjala
- Natural Resources Institute Finland, Bio-based Business and Industry, Parkano, Finland
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Wilson JP, Montañez IP, White JD, DiMichele WA, McElwain JC, Poulsen CJ, Hren MT. Dynamic Carboniferous tropical forests: new views of plant function and potential for physiological forcing of climate. THE NEW PHYTOLOGIST 2017; 215:1333-1353. [PMID: 28742257 DOI: 10.1111/nph.14700] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/22/2017] [Indexed: 05/05/2023]
Abstract
Contents 1333 I. 1334 II. 1335 III. 1339 IV. 1344 V. 1347 VI. 1347 1348 1348 References 1348 SUMMARY: The Carboniferous, the time of Earth's penultimate icehouse and widespread coal formation, was dominated by extinct lineages of early-diverging vascular plants. Studies of nearest living relatives of key Carboniferous plants suggest that their physiologies and growth forms differed substantially from most types of modern vegetation, particularly forests. It remains a matter of debate precisely how differently and to what degree these long-extinct plants influenced the environment. Integrating biophysical analysis of stomatal and vascular conductivity with geochemical analysis of fossilized tissues and process-based ecosystem-scale modeling yields a dynamic and unique perspective on these paleoforests. This integrated approach indicates that key Carboniferous plants were capable of growth and transpiration rates that approach values found in extant crown-group angiosperms, differing greatly from comparatively modest rates found in their closest living relatives. Ecosystem modeling suggests that divergent stomatal conductance, leaf sizes and stem life span between dominant clades would have shifted the balance of soil-atmosphere water fluxes, and thus surface runoff flux, during repeated, climate-driven, vegetation turnovers. This synthesis highlights the importance of 'whole plant' physiological reconstruction of extinct plants and the potential of vascular plants to have influenced the Earth system hundreds of millions of years ago through vegetation-climate feedbacks.
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Affiliation(s)
| | - Isabel P Montañez
- Department of Earth and Planetary Sciences, University of California, Davis, CA, 95616, USA
| | - Joseph D White
- Department of Biology, Baylor University, Waco, TX, 76798, USA
| | - William A DiMichele
- Department of Paleobiology, Smithsonian Museum of Natural History, Washington, DC, 20560, USA
| | - Jennifer C McElwain
- Earth Institute, School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Christopher J Poulsen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Michael T Hren
- Center for Integrative Geosciences, University of Connecticut, Storrs, CT, 06269, USA
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Reconstructing Extinct Plant Water Use for Understanding Vegetation–Climate Feedbacks: Methods, Synthesis, and a Case Study Using the Paleozoic-Era Medullosan Seed Ferns. ACTA ACUST UNITED AC 2017. [DOI: 10.1017/s1089332600003004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Vegetation affects feedbacks in Earth's hydrologic system, but is constrained by physiological adaptations. In extant ecosystems, the mechanisms controlling plant water used can be measured experimentally; for extinct plants in the recent geological past, water use can be inferred from nearest living relatives, assuming minimal evolutionary change. In deep time, where no close living relatives exist, fossil material provides the only information for inferring plant water use. However, mechanistic models for extinct plant water use must be built on first principles and tested on extant plants. Plants serve as a conduit for water movement from the soil to the atmosphere, constrained by tissue-level construction and gross architecture. No single feature, such as stomata or veins, encompasses enough of the complexity underpinning water-use physiology to serve as the basis of a model of functional water use in all (or perhaps any) extinct plants. Rather, a “functional whole plant” model must be used. To understand the interplay between plant and atmosphere, water use in relation to environmental conditions is investigated in an extinct plant, the seed fernMedullosa((Division Pteridospermatophyta), by reviewing methods for reconstructing physiological variables such as leaf and stem hydraulic capacity, photosynthetic rate, transpiration rate, stomatal conductance, and albedo. Medullosans had the potential for extremely high photosynthetic and assimilation rates, water transport, stomatal conductance, and transpiration—rates comparable to later angiosperms. When these high growth and gas exchange rates of medullosans are combined with the unique atmospheric gas composition of the late Paleozoic atmosphere, complex vegetation-environmental feedbacks are expected despite their basal phylogenetic position relative to post-Paleozoic seed plants.
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