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Nelsen MP, Moreau CS, Kevin Boyce C, Ree RH. Macroecological diversification of ants is linked to angiosperm evolution. Evol Lett 2023; 7:79-87. [PMID: 37033878 PMCID: PMC10078972 DOI: 10.1093/evlett/qrad008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 02/10/2023] [Accepted: 02/22/2023] [Indexed: 04/03/2023] Open
Abstract
Abstract
Ants are abundant, diverse, and occupy nearly all habitats and regions of the world. Previous work has demonstrated that ant diversification coincided with the rise of the angiosperms, and that several plant traits evolved as ants began to expand their nesting and foraging habits. In this study, we investigate whether associations with plants enabled niche expansion and are linked to climatic niche evolution in ants. Our analysis of over 1,400 ant species reveals that ancestral expansion from forest floors into the canopy and out into non-forested habitats closely followed evolutionary innovations in angiosperms. Several Paleogene-Neogene ant lineages independently diversified in non-forested habitats on multiple continents, tracking the evolution and expansion of elaiosome-bearing and arid-adapted angiosperms. The evolution of arboreal nesting tracked shifts in angiosperm physiology associated with the onset of everwet tropical rainforests, and climatic optima and rates of climatic niche evolution were linked to nesting location, with arboreally nesting groups having warmer and less seasonal climatic optima, and lower rates of climatic niche evolution. Our work further underscores the varied paths by which niche diversification occurred in ants, and how angiosperms influenced the ecological and evolutionary trajectories of interacting lineages.
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Affiliation(s)
- Matthew P Nelsen
- Corresponding author: The Field Museum, Negaunee Integrative Research Center, 1400 S. DuSable Lake Shore Drive, Chicago, IL 60605, USA.
| | - Corrie S Moreau
- The Field Museum, Negaunee Integrative Research Center, Chicago, IL, United States
- Departments of Entomology and Ecology & Evolutionary Biology, Cornell University, Ithaca, NY, United States
| | - C Kevin Boyce
- Department of Geological Sciences, Stanford University, Stanford, CA, United States
| | - Richard H Ree
- The Field Museum, Negaunee Integrative Research Center, Chicago, IL, United States
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2
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Boyce CK, Ibarra DE, D'Antonio MP. What we talk about when we talk about the long-term carbon cycle. New Phytol 2023; 237:1550-1557. [PMID: 36484141 DOI: 10.1111/nph.18665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 11/18/2022] [Indexed: 06/17/2023]
Abstract
The terrestrial biota is a crucial part of the long-term carbon cycle via the deposition of biomass as coal and other sedimentary organic matter and the impact of plants, fungi, and microbial life on the weathering of silicate minerals. Understanding these processes and their changes through time requires both geochemical modeling of the system as well as expertise in the living and fossil biotas and their ecological interactions, but details of these components are often lost in translation between disciplines. Here, we highlight misconceptions of the long-term carbon cycle that most frequently infiltrate the literature and hamper progress: mass balance requirements, the nature and duration of perturbations, opposing timescale constraints on biological and geological processes, and the role of models.
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Affiliation(s)
- C Kevin Boyce
- Department of Earth & Planetary Sciences, Stanford University, Stanford, CA, 94305, USA
| | - Daniel E Ibarra
- Institute at Brown for Environment and Society and the Department of Earth, Environmental and Planetary Science, Brown University, Providence, RI, 02906, USA
| | - Michael P D'Antonio
- Department of Earth & Planetary Sciences, Stanford University, Stanford, CA, 94305, USA
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3
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Boyce CK, Ibarra DE, Nelsen MP, D'Antonio MP. Nitrogen-based symbioses, phosphorus availability, and accounting for a modern world more productive than the Paleozoic. Geobiology 2023; 21:86-101. [PMID: 35949039 DOI: 10.1111/gbi.12519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/07/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Evolution of high-productivity angiosperms has been regarded as a driver of Mesozoic ecosystem restructuring. However, terrestrial productivity is limited by availability of rock-derived nutrients such as phosphorus for which permanent increases in weathering would violate mass balance requirements of the long-term carbon cycle. The potential reality of productivity increases sustained since the Mesozoic is supported here with documentation of a dramatic increase in the evolution of nitrogen-fixing or nitrogen-scavenging symbioses, including more than 100 lineages of ectomycorrhizal and lichen-forming fungi and plants with specialized microbial associations. Given this evidence of broadly increased nitrogen availability, we explore via carbon cycle modeling how enhanced phosphorus availability might be sustained without violating mass balance requirements. Volcanism is the dominant carbon input, dictating peaks in weathering outputs up to twice modern values. However, times of weathering rate suppression may be more important for setting system behavior, and the late Paleozoic was the only extended period over which rates are expected to have remained lower than modern. Modeling results are consistent with terrestrial organic matter deposition that accompanied Paleozoic vascular plant evolution having suppressed weathering fluxes by providing an alternative sink of atmospheric CO2 . Suppression would have then been progressively lifted as the crustal reservoir's holding capacity for terrestrial organic matter saturated back toward steady state with deposition of new organic matter balanced by erosion of older organic deposits. Although not an absolute increase, weathering fluxes returning to early Paleozoic conditions would represent a novel regime for the complex land biota that evolved in the interim. Volcanism-based peaks in Mesozoic weathering far surpass the modern rates that sustain a complex diversity of nitrogen-based symbioses; only in the late Paleozoic might these ecologies have been suppressed by significantly lower rates. Thus, angiosperms are posited to be another effect rather than proximal cause of Mesozoic upheaval.
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Affiliation(s)
- C Kevin Boyce
- Department of Geological Sciences, Stanford University, Stanford, California, USA
| | - Daniel E Ibarra
- Department of Geological Sciences, Stanford University, Stanford, California, USA
- Department of Earth and Planetary Science, University of California, Berkeley, California, USA
- Institute at Brown for Environment and Society and the Department of Earth, Environmental and Planetary Science, Brown University, Providence, Rhode Island, USA
| | - Matthew P Nelsen
- Negaunee Integrative Research Center, The Field Museum, Chicago, Illinois, USA
| | - Michael P D'Antonio
- Department of Geological Sciences, Stanford University, Stanford, California, USA
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4
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Schachat SR, Goldstein PZ, Desalle R, Bobo DM, Boyce CK, Payne JL, Labandeira CC. Illusion of flight? Absence, evidence and the age of winged insects. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Abstract
The earliest fossils of winged insects (Pterygota) are mid-Carboniferous (latest Mississippian, 328–324 Mya), but estimates of their age based on fossil-calibrated molecular phylogenetic studies place their origin at 440–370 Mya during the Silurian or Devonian. This discrepancy would require that winged insects evaded fossilization for at least the first ~50 Myr of their history. Here, we examine the plausibility of such a gap in the fossil record, and possible explanations for it, based on comparisons with the fossil records of other arthropod groups, the distribution of first occurrence dates of pterygote families, phylogenetically informed simulations of the fossilization of Palaeozoic insects, and re-analysis of data presented by Misof and colleagues using updated fossil calibrations under a variety of prior probability settings. We do not find support for the mechanisms previously suggested to account for such an extended gap in the pterygote fossil record, including sampling bias, preservation bias, and body size. We suggest that inference of an early origin of Pterygota long prior to their first appearance in the fossil record is probably an analytical artefact of taxon sampling and choice of fossil calibration points, possibly compounded by heterogeneity in rates of sequence evolution or speciation, including radiations or ‘bursts’ during their early history.
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Affiliation(s)
- Sandra R Schachat
- Department of Geological Sciences, Stanford University , Stanford, CA , USA
| | - Paul Z Goldstein
- Systematic Entomology Laboratory, USDA, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
| | - Rob Desalle
- American Museum of Natural History, Sackler Institute for Comparative Genomics , New York, NY , USA
| | - Dean M Bobo
- American Museum of Natural History, Sackler Institute for Comparative Genomics , New York, NY , USA
- Department of Ecology, Evolution, and Environmental Biology, Columbia University , New York, NY , USA
| | - C Kevin Boyce
- Department of Geological Sciences, Stanford University , Stanford, CA , USA
| | - Jonathan L Payne
- Department of Geological Sciences, Stanford University , Stanford, CA , USA
| | - Conrad C Labandeira
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
- Department of Entomology and Behavior, Ecology, Evolution, and Systematics Program, University of Maryland, College Park , MD , USA
- Capital Normal University, School of Life Sciences , Beijing , China
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5
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Affiliation(s)
- Michael P D'Antonio
- Department of Geological Sciences, Stanford University, 450 Jane Stanford Way, Building 320, Stanford, CA, 94305-2115, USA
| | - C Kevin Boyce
- Department of Geological Sciences, Stanford University, 450 Jane Stanford Way, Building 320, Stanford, CA, 94305-2115, USA
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Schachat SR, Boyce CK, Payne JL, Lentink D. Lepidoptera demonstrate the relevance of Murray's Law to circulatory systems with tidal flow. BMC Biol 2021; 19:204. [PMID: 34526028 PMCID: PMC8444497 DOI: 10.1186/s12915-021-01130-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 08/20/2021] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Murray's Law, which describes the branching architecture of bifurcating tubes, predicts the morphology of vessels in many amniotes and plants. Here, we use insects to explore the universality of Murray's Law and to evaluate its predictive power for the wing venation of Lepidoptera, one of the most diverse insect orders. Lepidoptera are particularly relevant to the universality of Murray's Law because their wing veins have tidal, or oscillatory, flow of air and hemolymph. We examined over one thousand wings representing 667 species of Lepidoptera. RESULTS We found that veins with a diameter above approximately 50 microns conform to Murray's Law, with veins below 50 microns in diameter becoming less and less likely to conform to Murray's Law as they narrow. The minute veins that are most likely to deviate from Murray's Law are also the most likely to have atrophied, which prevents efficient fluid transport regardless of branching architecture. However, the veins of many taxa continue to branch distally to the areas where they atrophied, and these too conform to Murray's Law at larger diameters (e.g., Sesiidae). CONCLUSIONS This finding suggests that conformity to Murray's Law in larger taxa may reflect requirements for structural support as much as fluid transport, or may indicate that selective pressures for fluid transport are stronger during the pupal stage-during wing development prior to vein atrophy-than the adult stage. Our results increase the taxonomic scope of Murray's Law and provide greater clarity about the relevance of body size.
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Affiliation(s)
| | - C. Kevin Boyce
- Department of Geological Sciences, Stanford University, Stanford, USA
| | - Jonathan L. Payne
- Department of Geological Sciences, Stanford University, Stanford, USA
| | - David Lentink
- Department of Mechanical Engineering, Stanford University, Stanford, USA
- Faculty of Science and Engineering, University of Groningen, Groningen, The Netherlands
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7
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Théroux-Rancourt G, Roddy AB, Earles JM, Gilbert ME, Zwieniecki MA, Boyce CK, Tholen D, McElrone AJ, Simonin KA, Brodersen CR. Maximum CO 2 diffusion inside leaves is limited by the scaling of cell size and genome size. Proc Biol Sci 2021; 288:20203145. [PMID: 33622134 PMCID: PMC7934972 DOI: 10.1098/rspb.2020.3145] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 01/27/2021] [Indexed: 12/19/2022] Open
Abstract
Maintaining high rates of photosynthesis in leaves requires efficient movement of CO2 from the atmosphere to the mesophyll cells inside the leaf where CO2 is converted into sugar. CO2 diffusion inside the leaf depends directly on the structure of the mesophyll cells and their surrounding airspace, which have been difficult to characterize because of their inherently three-dimensional organization. Yet faster CO2 diffusion inside the leaf was probably critical in elevating rates of photosynthesis that occurred among angiosperm lineages. Here we characterize the three-dimensional surface area of the leaf mesophyll across vascular plants. We show that genome size determines the sizes and packing densities of cells in all leaf tissues and that smaller cells enable more mesophyll surface area to be packed into the leaf volume, facilitating higher CO2 diffusion. Measurements and modelling revealed that the spongy mesophyll layer better facilitates gaseous phase diffusion while the palisade mesophyll layer better facilitates liquid-phase diffusion. Our results demonstrate that genome downsizing among the angiosperms was critical to restructuring the entire pathway of CO2 diffusion into and through the leaf, maintaining high rates of CO2 supply to the leaf mesophyll despite declining atmospheric CO2 levels during the Cretaceous.
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Affiliation(s)
| | - Adam B. Roddy
- Institute of Environment, Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
| | - J. Mason Earles
- Department of Viticulture and Enology, University of California, Davis, CA 95616, USA
- Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA
| | - Matthew E. Gilbert
- Department of Plant Sciences, University of California, Davis, CA 95616, USA
| | | | - C. Kevin Boyce
- Department of Geological Sciences, Stanford University, Palo Alto, CA 94305, USA
| | - Danny Tholen
- Institute of Botany, University of Natural Resources and Life Sciences, 1180 Vienna, Austria
| | - Andrew J. McElrone
- Department of Viticulture and Enology, University of California, Davis, CA 95616, USA
- USDA-Agricultural Research Service, Davis, CA 95616, USA
| | - Kevin A. Simonin
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
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8
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D'Antonio MP, Boyce CK. Arborescent lycopsid periderm production was limited. New Phytol 2020; 228:741-751. [PMID: 32506426 DOI: 10.1111/nph.16727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 05/26/2020] [Indexed: 06/11/2023]
Abstract
Late Paleozoic arborescent lycopsids have been thought to have grown from sporelings into large trees through the production of a periderm cylinder, particularly massive in the proximal portion of the trunk and tapering distally, with this rind of bark providing most of their structural support. Here, we argue that physiological limitations would have prohibited the production of thick periderm and test this hypothesis using multiple independent lines of evidence derived from anatomical permineralization and surface impression fossils that allow both direct and indirect measurement of periderm radial thickness. Across all six genera of Pennsylvanian arborescent lycopsids that were investigated, all evidence indicates limited periderm production: typically < 5 cm, always < 15 cm, even in trunks that would have reached 1 m or more in diameter. The large amount of arborescent lycopsid periderm in Middle Pennsylvanian coals represents taphonomic enrichment rather than a true anatomical signal, complicating interpretation of their biology including biomechanics and early ontogeny.
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Affiliation(s)
- Michael P D'Antonio
- Department of Geological Sciences, Stanford University, 450 Jane Stanford Way, Building 320, Stanford, CA, 94305-2115, USA
| | - C Kevin Boyce
- Department of Geological Sciences, Stanford University, 450 Jane Stanford Way, Building 320, Stanford, CA, 94305-2115, USA
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9
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Nelsen MP, Lücking R, Boyce CK, Lumbsch HT, Ree RH. The macroevolutionary dynamics of symbiotic and phenotypic diversification in lichens. Proc Natl Acad Sci U S A 2020; 117:21495-21503. [PMID: 32796103 PMCID: PMC7474681 DOI: 10.1073/pnas.2001913117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Symbioses are evolutionarily pervasive and play fundamental roles in structuring ecosystems, yet our understanding of their macroevolutionary origins, persistence, and consequences is incomplete. We traced the macroevolutionary history of symbiotic and phenotypic diversification in an iconic symbiosis, lichens. By inferring the most comprehensive time-scaled phylogeny of lichen-forming fungi (LFF) to date (over 3,300 species), we identified shifts among symbiont classes that broadly coincided with the convergent evolution of phylogenetically or functionally similar associations in diverse lineages (plants, fungi, bacteria). While a relatively recent loss of lichenization in Lecanoromycetes was previously identified, our work instead suggests lichenization was abandoned far earlier, interrupting what had previously been considered a direct switch between trebouxiophycean and trentepohlialean algal symbionts. Consequently, some of the most diverse clades of LFF are instead derived from nonlichenized ancestors and re-evolved lichenization with Trentepohliales algae, a clade that also facilitated lichenization in unrelated lineages of LFF. Furthermore, while symbiont identity and symbiotic phenotype influence the ecology and physiology of lichens, they are not correlated with rates of lineage birth and death, suggesting more complex dynamics underly lichen diversification. Finally, diversification patterns of LFF differed from those of wood-rotting and ectomycorrhizal taxa, likely reflecting contrasts in their fundamental biological properties. Together, our work provides a timeline for the ecological contributions of lichens, and reshapes our understanding of symbiotic persistence in a classic model of symbiosis.
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Affiliation(s)
- Matthew P Nelsen
- Department of Science and Education, Negaunee Integrative Research Center, The Field Museum, Chicago, IL 60605;
| | - Robert Lücking
- Botanischer Garten und Botanisches Museum, Freie Universität Berlin, 14195 Berlin, Germany
| | - C Kevin Boyce
- Department of Geological Sciences, Stanford University, Stanford, CA 94305
| | - H Thorsten Lumbsch
- Department of Science and Education, Negaunee Integrative Research Center, The Field Museum, Chicago, IL 60605
| | - Richard H Ree
- Department of Science and Education, Negaunee Integrative Research Center, The Field Museum, Chicago, IL 60605
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10
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Nelsen MP, Lücking R, Boyce CK, Lumbsch HT, Ree RH. No support for the emergence of lichens prior to the evolution of vascular plants. Geobiology 2020; 18:3-13. [PMID: 31729136 DOI: 10.1111/gbi.12369] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/28/2019] [Accepted: 10/05/2019] [Indexed: 06/10/2023]
Abstract
The early-successional status of lichens in modern terrestrial ecosystems, together with the role lichen-mediated weathering plays in the carbon cycle, have contributed to the long and widely held assumption that lichens occupied early terrestrial ecosystems prior to the evolution of vascular plants and drove global change during this time. Their poor preservation potential and the classification of ambiguous fossils as lichens or other fungal-algal associations have further reinforced this view. As unambiguous fossil data are lacking to demonstrate the presence of lichens prior to vascular plants, we utilize an alternate approach to assess their historic presence in early terrestrial ecosystems. Here, we analyze new time-calibrated phylogenies of ascomycete fungi and chlorophytan algae, that intensively sample lineages with lichen symbionts. Age estimates for several interacting clades show broad congruence and demonstrate that fungal origins of lichenization postdate the earliest tracheophytes. Coupled with the absence of unambiguous fossil data, our work finds no support for lichens having mediated global change during the Neoproterozoic-early Paleozoic prior to vascular plants. We conclude by discussing our findings in the context of Neoproterozoic-Paleozoic terrestrial ecosystem evolution and the paleoecological context in which vascular plants evolved.
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Affiliation(s)
- Matthew P Nelsen
- Department of Science and Education, The Field Museum, Integrative Research Center, Chicago, IL, USA
- Committee on Evolutionary Biology, University of Chicago, Chicago, IL, USA
| | - Robert Lücking
- Botanischer Garten und Botanisches Museum, Freie Universität Berlin, Berlin, Germany
| | - C Kevin Boyce
- Department of Geological Sciences, Stanford University, Stanford, California, USA
| | - H Thorsten Lumbsch
- Department of Science and Education, The Field Museum, Integrative Research Center, Chicago, IL, USA
| | - Richard H Ree
- Department of Science and Education, The Field Museum, Integrative Research Center, Chicago, IL, USA
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Abstract
The twining habit is a climbing strategy that helps slender plants grow upward by using circumnutation around other plants. In geological history, climbing may have already been present in the first Middle Devonian forests, as indicated by possible climbers among aneurophytalean progymnosperms [1] and lycopsids [2]. By the late Carboniferous, climbing was both more common and diverse - preserved in swamp forests with modes of attachment ranging from aerial roots to appendages modified into hooks and tendrils on the leaves [3]. However, all of these diagnoses of a climbing habit are based upon either indirect morphological characteristics of the purported climber or on direct physical contact with a host plant, but without direct preservation of twining [3,4]. Permineralized epiphytes have been preserved in the Carboniferous [5], but the interpretation of scars purported to have been caused by twiners that have been found on trunk compressions of potential host-plants has been questioned [5] (see Supplemental Information). Direct preservation of a climber engaged in true twining around a host has only been documented in the Miocene Shanwang Formation of Eastern China, albeit with the identity of the twiner difficult to establish and likely to be a self-twiner [6]. Here, we report a climbing fern engaged in left-handed twining around a seed plant from the early Permian Wuda Tuff fossil Lagerstätte of Inner Mongolia, China [7]. Moreover, the host plant is likely to also be a climber based on its overall form. Such a climber-climbing-a-climber phenomenon signals the potential ecological complexity of late Paleozoic forests.
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Affiliation(s)
- Weiming Zhou
- 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
| | - Dandan Li
- 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; University of Chinese Academy of Sciences, Beijing, China
| | - Josef Pšenička
- 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; Centre of Palaeobiodiversity, West Bohemian Museum in Pilsen, Pilsen, Czech Republic
| | - C Kevin Boyce
- Geological Sciences, Stanford University, Stanford, CA, USA
| | - Jun Wang
- 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; University of Chinese Academy of Sciences, Beijing, China.
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12
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Boyce CK, Zwieniecki MA. The prospects for constraining productivity through time with the whole-plant physiology of fossils. New Phytol 2019; 223:40-49. [PMID: 30304562 DOI: 10.1111/nph.15446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 02/26/2018] [Indexed: 06/08/2023]
Abstract
Anatomically preserved fossils allow estimation of hydraulic parameters, potentially providing constraints on interpreting whole-plant physiology. However, different organ systems have typically been considered in isolation - a problem given common mismatches of high and low conductance components coupled in the hydraulic path of the same plant. A recent paper addressed the issue of how to handle resistance mismatches in fossil plant hydraulics, focusing on Carboniferous medullosan seed plants and arborescent lycopsids. Among other problems, however, a fundamental error was made: the transpiration stream consists of resistances in series (where resistances are additive and the component with the largest resistance can dominate the behavior of the system), but emphasis was instead placed on the lowest resistance, effectively treating the system as resistances in parallel (where the component with the smallest resistance will dominate the behavior). Instead of possessing high assimilation capacities to match high specific stem conductances, it is argued here that individual high conductance components in these Paleozoic plants are nonetheless associated with low whole-plant productivity, just as can be commonly seen in living plants. Resolution of how to handle these issues may have broad implications for the Earth system including geobiological feedbacks to rock weathering, atmospheric composition, and climate.
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Affiliation(s)
- C Kevin Boyce
- Geological Sciences, Stanford University, Stanford, CA, 94305, USA
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13
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Baresch A, Crifò C, Boyce CK. Competition for epidermal space in the evolution of leaves with high physiological rates. New Phytol 2019; 221:628-639. [PMID: 30216453 DOI: 10.1111/nph.15476] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 08/27/2018] [Indexed: 06/08/2023]
Abstract
Leaves with high photosynthetic capacity require high transpiration capacity. Consequently, hydraulic conductance, stomatal conductance, and assimilation capacities should be positively correlated. These traits make independent demands on anatomical space, particularly due to the propensity for veins to have bundle sheath extensions that exclude stomata from the local epidermis. We measured density and area occupation of bundle sheath extensions, density and size of stomata and subsidiary cells, and venation density for a sample of extant angiosperms and fossil and living nonangiosperm tracheophytes. For most nonangiosperms, even modest increases in vein density and stomatal conductance would require substantial reconfigurations of anatomy. One characteristic of the angiosperm syndrome (e.g. small cell sizes, etc.) is hierarchical vein networks that allow expression of bundle sheath extensions in some, but not all veins, contrasting with all-or-nothing alternatives available with the single-order vein networks in most nonangiosperms. Bundle sheath modulation is associated with higher vein densities in three independent groups with hierarchical venation: angiosperms, Gnetum (gymnosperm) and Dipteris (fern). Anatomical and developmental constraints likely contribute to the stability in leaf characteristics - and ecophysiology - seen through time in different lineages and contribute to the uniqueness of angiosperms in achieving the highest vein densities, stomatal densities, and physiological rates.
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Affiliation(s)
- Andrés Baresch
- Department of Geological Sciences, Stanford University, Stanford, CA, 94305, USA
- Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá
| | - Camilla Crifò
- Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá
- Department of Biology, University of Washington, Seattle, WA, 98195, USA
| | - C Kevin Boyce
- Department of Geological Sciences, Stanford University, Stanford, CA, 94305, USA
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14
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Kevin Boyce C, DiMichele WA. Fast or slow for the arborescent lycopsids?: Response to Thomas & Cleal (2018) 'Arborescent lycophyte growth in the late Carboniferous coal swamps'. New Phytol 2018; 218:891-893. [PMID: 29457227 DOI: 10.1111/nph.15059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
- C Kevin Boyce
- Geological Sciences, Stanford University, Stanford, CA, 94305, USA
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Schachat SR, Labandeira CC, Saltzman MR, Cramer BD, Payne JL, Boyce CK. Phanerozoic pO 2 and the early evolution of terrestrial animals. Proc Biol Sci 2018; 285:20172631. [PMID: 29367401 PMCID: PMC5805952 DOI: 10.1098/rspb.2017.2631] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 01/03/2018] [Indexed: 11/12/2022] Open
Abstract
Concurrent gaps in the Late Devonian/Mississippian fossil records of insects and tetrapods (i.e. Romer's Gap) have been attributed to physiological suppression by low atmospheric pO2 Here, updated stable isotope inputs inform a reconstruction of Phanerozoic oxygen levels that contradicts the low oxygen hypothesis (and contradicts the purported role of oxygen in the evolution of gigantic insects during the late Palaeozoic), but reconciles isotope-based calculations with other proxies, like charcoal. Furthermore, statistical analysis demonstrates that the gap between the first Devonian insect and earliest diverse insect assemblages of the Pennsylvanian (Bashkirian Stage) requires no special explanation if insects were neither diverse nor abundant prior to the evolution of wings. Rather than tracking physiological constraint, the fossil record may accurately record the transformative evolutionary impact of insect flight.
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Affiliation(s)
- Sandra R Schachat
- Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
- Department of Paleobiology, Smithsonian Institution, Washington, DC 20013, USA
| | - Conrad C Labandeira
- Department of Paleobiology, Smithsonian Institution, Washington, DC 20013, USA
- Department of Entomology, University of Maryland, College Park, MD 20742, USA
- College of Life Sciences, Capital Normal University, Beijing 100048, People's Republic of China
| | - Matthew R Saltzman
- School of Earth Sciences, Ohio State University, Columbus, OH 43214, USA
| | - Bradley D Cramer
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - Jonathan L Payne
- Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
| | - C Kevin Boyce
- Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
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16
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Théroux-Rancourt G, Earles JM, Gilbert ME, Zwieniecki MA, Boyce CK, McElrone AJ, Brodersen CR. The bias of a two-dimensional view: comparing two-dimensional and three-dimensional mesophyll surface area estimates using noninvasive imaging. New Phytol 2017; 215:1609-1622. [PMID: 28691233 DOI: 10.1111/nph.14687] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 06/05/2017] [Indexed: 05/22/2023]
Abstract
The mesophyll surface area exposed to intercellular air space per leaf area (Sm ) is closely associated with CO2 diffusion and photosynthetic rates. Sm is typically estimated from two-dimensional (2D) leaf sections and corrected for the three-dimensional (3D) geometry of mesophyll cells, leading to potential differences between the estimated and actual cell surface area. Here, we examined how 2D methods used for estimating Sm compare with 3D values obtained from high-resolution X-ray microcomputed tomography (microCT) for 23 plant species, with broad phylogenetic and anatomical coverage. Relative to 3D, uncorrected 2D Sm estimates were, on average, 15-30% lower. Two of the four 2D Sm methods typically fell within 10% of 3D values. For most species, only a few 2D slices were needed to accurately estimate Sm within 10% of the whole leaf sample median. However, leaves with reticulate vein networks required more sections because of a more heterogeneous vein coverage across slices. These results provide the first comparison of the accuracy of 2D methods in estimating the complex 3D geometry of internal leaf surfaces. Because microCT is not readily available, we provide guidance for using standard light microscopy techniques, as well as recommending standardization of reporting Sm values.
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Affiliation(s)
| | - J Mason Earles
- School of Forestry & Environmental Studies, Yale University, New Haven, CT, 06511, USA
| | - Matthew E Gilbert
- Department of Plant Sciences, University of California Davis, Davis, CA, 95616, USA
| | - Maciej A Zwieniecki
- Department of Plant Sciences, University of California Davis, Davis, CA, 95616, USA
| | - C Kevin Boyce
- Department of Geological Sciences, Stanford University, Stanford, CA, 94305, USA
| | - Andrew J McElrone
- USDA-Agricultural Research Service, Davis, CA, 95616, USA
- Deparment of Viticulture and Enology, University of California, Davis, CA, 95616, USA
| | - Craig R Brodersen
- School of Forestry & Environmental Studies, Yale University, New Haven, CT, 06511, USA
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17
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Boyce CK, Fan Y, Zwieniecki MA. Did trees grow up to the light, up to the wind, or down to the water? How modern high productivity colors perception of early plant evolution. New Phytol 2017; 215:552-557. [PMID: 28054354 DOI: 10.1111/nph.14387] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 11/06/2016] [Indexed: 06/06/2023]
Abstract
Contents I. II. III. IV. V. Acknowledgements References SUMMARY: Flowering plants can be far more productive than other living land plants. Evidence is reviewed that productivity would have been uniformly lower and less CO2 -responsive before angiosperm evolution, particularly during the early evolution of vascular plants and forests in the Devonian and Carboniferous. This introduces important challenges because paleoecological interpretations have been rooted in understanding of modern angiosperm-dominated ecosystems. One key example is tree evolution: although often thought to reflect competition for light, light limitation is unlikely for plants with such low photosynthetic potential. Instead, during this early evolution, the capacities of trees for enhanced propagule dispersal, greater leaf area, and deep-rooting access to nutrients and the water table are all deemed more fundamental potential drivers than light.
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Affiliation(s)
- C Kevin Boyce
- Geological Sciences, Stanford University, Stanford, CA, 94305, USA
| | - Ying Fan
- Earth & Planetary Sciences, Rutgers University, New Brunswick, NJ, 08544, USA
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18
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Zwieniecki MA, Haaning KS, Boyce CK, Jensen KH. Stomatal design principles in synthetic and real leaves. J R Soc Interface 2016; 13:20160535. [PMID: 27807270 PMCID: PMC5134010 DOI: 10.1098/rsif.2016.0535] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 10/07/2016] [Indexed: 11/12/2022] Open
Abstract
Stomata are portals in plant leaves that control gas exchange for photosynthesis, a process fundamental to life on Earth. Gas fluxes and plant productivity depend on external factors such as light, water and CO2 availability and on the geometrical properties of the stoma pores. The link between stoma geometry and environmental factors has informed a wide range of scientific fields-from agriculture to climate science, where observed variations in stoma size and density are used to infer prehistoric atmospheric CO2 content. However, the physical mechanisms and design principles responsible for major trends in stomatal patterning are not well understood. Here, we use a combination of biomimetic experiments and theory to rationalize the observed changes in stoma geometry. We show that the observed correlations between stoma size and density are consistent with the hypothesis that plants favour efficient use of space and maximum control of dynamic gas conductivity, and that the capacity for gas exchange in plants has remained constant over at least the last 325 Myr. Our analysis provides a new measure to gauge the relative performance of species based on their stomatal characteristics.
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Affiliation(s)
- Maciej A Zwieniecki
- Department of Plant Sciences, University of California, Davis, CA 95616, USA
| | - Katrine S Haaning
- Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - C Kevin Boyce
- Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
| | - Kaare H Jensen
- Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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19
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Abstract
Organic carbon burial plays a critical role in Earth systems, influencing atmospheric O2 and CO2 concentrations and, thereby, climate. The Carboniferous Period of the Paleozoic is so named for massive, widespread coal deposits. A widely accepted explanation for this peak in coal production is a temporal lag between the evolution of abundant lignin production in woody plants and the subsequent evolution of lignin-degrading Agaricomycetes fungi, resulting in a period when vast amounts of lignin-rich plant material accumulated. Here, we reject this evolutionary lag hypothesis, based on assessment of phylogenomic, geochemical, paleontological, and stratigraphic evidence. Lignin-degrading Agaricomycetes may have been present before the Carboniferous, and lignin degradation was likely never restricted to them and their class II peroxidases, because lignin modification is known to occur via other enzymatic mechanisms in other fungal and bacterial lineages. Furthermore, a large proportion of Carboniferous coal horizons are dominated by unlignified lycopsid periderm with equivalent coal accumulation rates continuing through several transitions between floral dominance by lignin-poor lycopsids and lignin-rich tree ferns and seed plants. Thus, biochemical composition had little relevance to coal accumulation. Throughout the fossil record, evidence of decay is pervasive in all organic matter exposed subaerially during deposition, and high coal accumulation rates have continued to the present wherever environmental conditions permit. Rather than a consequence of a temporal decoupling of evolutionary innovations between fungi and plants, Paleozoic coal abundance was likely the result of a unique combination of everwet tropical conditions and extensive depositional systems during the assembly of Pangea.
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Affiliation(s)
| | - William A DiMichele
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560
| | - Shanan E Peters
- Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706
| | - C Kevin Boyce
- Geological Sciences, Stanford University, Stanford, CA 94305;
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20
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Lee JE, Frankenberg C, van der Tol C, Berry JA, Guanter L, Boyce CK, Fisher JB, Morrow E, Worden JR, Asefi S, Badgley G, Saatchi S. Forest productivity and water stress in Amazonia: observations from GOSAT chlorophyll fluorescence. Proc Biol Sci 2013; 280:20130171. [PMID: 23760636 DOI: 10.1098/rspb.2013.0171] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
It is unclear to what extent seasonal water stress impacts on plant productivity over Amazonia. Using new Greenhouse gases Observing SATellite (GOSAT) satellite measurements of sun-induced chlorophyll fluorescence, we show that midday fluorescence varies with water availability, both of which decrease in the dry season over Amazonian regions with substantial dry season length, suggesting a parallel decrease in gross primary production (GPP). Using additional SeaWinds Scatterometer onboard QuikSCAT satellite measurements of canopy water content, we found a concomitant decrease in daily storage of canopy water content within branches and leaves during the dry season, supporting our conclusion. A large part (r(2) = 0.75) of the variance in observed monthly midday fluorescence from GOSAT is explained by water stress over moderately stressed evergreen forests over Amazonia, which is reproduced by model simulations that include a full physiological representation of photosynthesis and fluorescence. The strong relationship between GOSAT and model fluorescence (r(2) = 0.79) was obtained using a fixed leaf area index, indicating that GPP changes are more related to environmental conditions than chlorophyll contents. When the dry season extended to drought in 2010 over Amazonia, midday basin-wide GPP was reduced by 15 per cent compared with 2009.
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Affiliation(s)
- Jung-Eun Lee
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
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Boyce CK, Zwieniecki MA. Leaf fossil record suggests limited influence of atmospheric CO2 on terrestrial productivity prior to angiosperm evolution. Proc Natl Acad Sci U S A 2012; 109:10403-8. [PMID: 22689947 PMCID: PMC3387114 DOI: 10.1073/pnas.1203769109] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Declining CO(2) over the Cretaceous has been suggested as an evolutionary driver of the high leaf vein densities (7-28 mm mm(-2)) that are unique to the angiosperms throughout all of Earth history. Photosynthetic modeling indicated the link between high vein density and productivity documented in the modern low-CO(2) regime would be lost as CO(2) concentrations increased but also implied that plants with very low vein densities (less than 3 mm mm(-2)) should experience substantial disadvantages with high CO(2). Thus, the hypothesized relationship between CO(2) and plant evolution can be tested through analysis of the concurrent histories of alternative lineages, because an extrinsic driver like atmospheric CO(2) should affect all plants and not just the flowering plants. No such relationship is seen. Regardless of CO(2) concentrations, low vein densities are equally common among nonangiosperms throughout history and common enough to include forest canopies and not just obligate shade species that will always be of limited productivity. Modeling results can be reconciled with the fossil record if maximum assimilation rates of nonflowering plants are capped well below those of flowering plants, capturing biochemical and physiological differences that would be consistent with extant plants but previously unrecognized in the fossil record. Although previous photosynthetic modeling suggested that productivity would double or triple with each Phanerozoic transition from low to high CO(2), productivity changes are likely to have been limited before a substantial increase accompanying the evolution of flowering plants.
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Affiliation(s)
- C Kevin Boyce
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA.
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22
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Nicotra AB, Leigh A, Boyce CK, Jones CS, Niklas KJ, Royer DL, Tsukaya H. The evolution and functional significance of leaf shape in the angiosperms. Funct Plant Biol 2011; 38:535-552. [PMID: 32480907 DOI: 10.1071/fp11057] [Citation(s) in RCA: 203] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 05/30/2011] [Indexed: 05/18/2023]
Abstract
Angiosperm leaves manifest a remarkable diversity of shapes that range from developmental sequences within a shoot and within crown response to microenvironment to variation among species within and between communities and among orders or families. It is generally assumed that because photosynthetic leaves are critical to plant growth and survival, variation in their shape reflects natural selection operating on function. Several non-mutually exclusive theories have been proposed to explain leaf shape diversity. These include: thermoregulation of leaves especially in arid and hot environments, hydraulic constraints, patterns of leaf expansion in deciduous species, biomechanical constraints, adaptations to avoid herbivory, adaptations to optimise light interception and even that leaf shape variation is a response to selection on flower form. However, the relative importance, or likelihood, of each of these factors is unclear. Here we review the evolutionary context of leaf shape diversification, discuss the proximal mechanisms that generate the diversity in extant systems, and consider the evidence for each the above hypotheses in the context of the functional significance of leaf shape. The synthesis of these broad ranging areas helps to identify points of conceptual convergence for ongoing discussion and integrated directions for future research.
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Affiliation(s)
- Adrienne B Nicotra
- Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Andrea Leigh
- School of the Environment, University of Technology, Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - C Kevin Boyce
- Department of the Geophysical Sciences, 5734 S. Ellis Avenue, Chicago, IL 60637, USA
| | - Cynthia S Jones
- Department of Ecology and Evolutionary Biology, University of Connecticut, 75 N. Eagleville Road, Unit-3043, Storrs, CT 06269, USA
| | - Karl J Niklas
- Department of Plant Biology, Cornell University, 412 Mann Library Building, Cornell University, Ithaca, NY 14853, USA
| | - Dana L Royer
- Department of Earth and Environmental Sciences, Wesleyan University, 265 Church Street, Middletown, CT 06459, USA
| | - Hirokazu Tsukaya
- Graduate School of Science, University of Tokyo, Science Build #2, 7-3-1 Hongo, Tokyo 113-0033, Japan
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23
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Leigh A, Zwieniecki MA, Rockwell FE, Boyce CK, Nicotra AB, Holbrook NM. Structural and hydraulic correlates of heterophylly in Ginkgo biloba. New Phytol 2011; 189:459-70. [PMID: 20880226 DOI: 10.1111/j.1469-8137.2010.03476.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
This study investigates the functional significance of heterophylly in Ginkgo biloba, where leaves borne on short shoots are ontogenetically distinct from those on long shoots. Short shoots are compact, with minimal internodal elongation; their leaves are supplied with water through mature branches. Long shoots extend the canopy and have significant internodal elongation; their expanding leaves receive water from a shoot that is itself maturing. Morphology, stomatal traits, hydraulic architecture, Huber values, water transport efficiency, in situ gas exchange and laboratory-based steady-state hydraulic conductance were examined for each leaf type. Both structure and physiology differed markedly between the two leaf types. Short-shoot leaves were thinner and had higher vein density, lower stomatal pore index, smaller bundle sheath extensions and lower hydraulic conductance than long-shoot leaves. Long shoots had lower xylem area:leaf area ratios than short shoots during leaf expansion, but this ratio was reversed at shoot maturity. Long-shoot leaves had higher rates of photosynthesis, stomatal conductance and transpiration than short-shoot leaves. We propose that structural differences between the two G. biloba leaf types reflect greater hydraulic limitation of long-shoot leaves during expansion. In turn, differences in physiological performance of short- and long-shoot leaves correspond to their distinct ontogeny and architecture.
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Affiliation(s)
- A Leigh
- Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia.
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Hobbie EA, Boyce CK. Carbon sources for the Palaeozoic giant fungus Prototaxites inferred from modern analogues. Proc Biol Sci 2010; 277:2149-56. [PMID: 20335209 PMCID: PMC2880155 DOI: 10.1098/rspb.2010.0201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 03/01/2010] [Indexed: 11/12/2022] Open
Abstract
A wide range of carbon isotope values in the Devonian fossil Prototaxites has been interpreted to support heterotrophy and the classification of Prototaxites as a giant fungus. This inference remains controversial because of the huge size of Prototaxites relative to co-occurring terrestrial vegetation and the lack of existing fungal analogues that display equally broad isotopic ranges. Here, we show wide isotopic variability in the modern saprotrophic fungus Arrhenia obscurata collected adjacent to shallow meltwater pools of a sparsely vegetated glacial succession in the Washington Cascades, USA. Soils collected specifically around the edges of these pools were up to 5 per thousand higher in delta(13)C than adjacent soils consistent with C(3) origin. Microbial sources of primary production appear to cause these high delta(13)C values, and the environment may be analogous to that of the Early Devonian landscapes, where Prototaxites individuals with extreme isotopic variance were found. Carbon isotopes are also compared in Prototaxites, Devonian terrestrial vascular plants, and Devonian algal-derived lake sediments. Prototaxites isotopic values show little correspondence with those of contemporaneous tracheophytes, providing further evidence that non-vascular land plants or aquatic microbes were important contributors to its carbon sources. Thus, a saprotrophic fungal identity is supported for Prototaxites, which may have relied on deposits of algal-derived organic matter in floodplain environments that were less dominated by vascular plants than a straight reading of the macrofossil record might suggest.
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Affiliation(s)
- Erik A Hobbie
- Complex Systems Research Center, University of New Hampshire, Durham, NH 03824, USA.
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25
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Affiliation(s)
- C Kevin Boyce
- Department of the Geophysical Sciences, University of Chicago, Chicago, Illinois
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26
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Abstract
Movement of water from soil to atmosphere by plant transpiration can feed precipitation, but is limited by the hydraulic capacities of plants, which have not been uniform through time. The flowering plants that dominate modern vegetation possess transpiration capacities that are dramatically higher than any other plants, living or extinct. Transpiration operates at the level of the leaf, however, and how the impact of this physiological revolution scales up to the landscape and larger environment remains unclear. Here, climate modelling demonstrates that angiosperms help ensure aseasonally high levels of precipitation in the modern tropics. Most strikingly, replacement of angiosperm with non-angiosperm vegetation would result in a hotter, drier and more seasonal Amazon basin, decreasing the overall area of ever-wet rainforest by 80 per cent. Thus, flowering plant ecological dominance has strongly altered climate and the global hydrological cycle. Because tropical biodiversity is closely tied to precipitation and rainforest area, angiosperm climate modification may have promoted diversification of the angiosperms themselves, as well as radiations of diverse vertebrate and invertebrate animal lineages and of epiphytic plants. Their exceptional potential for environmental modification may have contributed to divergent responses to similar climates and global perturbations, like mass extinctions, before and after angiosperm evolution.
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Affiliation(s)
- C Kevin Boyce
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA.
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27
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Boyce CK. The evolution of plant development in a paleontological context. Curr Opin Plant Biol 2010; 13:102-7. [PMID: 19897405 DOI: 10.1016/j.pbi.2009.10.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 09/22/2009] [Accepted: 10/09/2009] [Indexed: 05/05/2023]
Abstract
Contrary to what might be expected from the observation of extant plants alone, the fossil record indicates that most aspects of vascular plant form evolved multiple times during their Paleozoic radiation. Opportunity is increasing to unite information from fossil and living plants to understand the evolution of developmental mechanisms and each field can provide tests for hypotheses derived from the other. The paleontological context to recent advances in developmental genetics is reviewed for the evolution of a functionally independent sporophyte generation, of leaves, and of roots-all of which are integral to understanding the explosive radiation of vascular plants during the Devonian, 400 million years ago.
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Affiliation(s)
- C Kevin Boyce
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA.
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Abstract
Although a variety of leaf characteristics appear to be induced by light environment during development, analysis of ontogenetic changes in living broad leaved trees has suggested that a number of other traits also lumped into the classic 'sun' versus 'shade' morphological distinctions, including leaf size, shape, and vein density, are instead controlled largely by local hydraulic environment within the tree canopy. The regularity in how these traits vary with canopy placement suggests a method for addressing a classic paleobotanical quandary: the stature of the source plant - from herb or shrub to canopy tree - is typically unknown for leaf fossils. The study of Ginkgo here complements previous work on Quercus that indicated that leaves throughout the crown are identical in size and venation at the time of bud break and that morphological adaptation to the local microenvironment takes place largely during the expansion phase after the determination of the vascular architecture is complete. Hence, variation in vein density does not reflect differential vein production so much as the distortion of similar vein networks over different final surface areas driven by variation in local hydraulic supply during expansion. Unlike the diffusely growing leaves of the angiosperm, Quercus, the marginally growing leaves of Ginkgo do show some potential for differential vein production, but expansion effects still dominate. The approach suggested here may prove useful for assessing the likelihood that two distinct fossil morphospecies actually represent leaves of the same plant and to gather information concerning canopy structure from disarticulated leaves.
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Affiliation(s)
- C K Boyce
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA.
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29
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Boyce CK, Brodribb TJ, Feild TS, Zwieniecki MA. Angiosperm leaf vein evolution was physiologically and environmentally transformative. Proc Biol Sci 2009; 276:1771-6. [PMID: 19324775 PMCID: PMC2674498 DOI: 10.1098/rspb.2008.1919] [Citation(s) in RCA: 202] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The veins that irrigate leaves during photosynthesis are demonstrated to be strikingly more abundant in flowering plants than in any other vascular plant lineage. Angiosperm vein densities average 8 mm of vein per mm(2) of leaf area and can reach 25 mm mm(-2), whereas such high densities are absent from all other plants, living or extinct. Leaves of non-angiosperms have consistently averaged close to 2 mm mm(-2) throughout 380 million years of evolution despite a complex history that has involved four or more independent origins of laminate leaves with many veins and dramatic changes in climate and atmospheric composition. We further demonstrate that the high leaf vein densities unique to the angiosperms enable unparalleled transpiration rates, extending previous work indicating a strong correlation between vein density and assimilation rates. Because vein density is directly measurable in fossils, these correlations provide new access to the physiology of extinct plants and how they may have impacted their environments. First, the high assimilation rates currently confined to the angiosperms among living plants are likely to have been unique throughout evolutionary history. Second, the transpiration-driven recycling of water that is important for bolstering precipitation in modern tropical rainforests might have been significantly less in a world before the angiosperms.
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Affiliation(s)
- C Kevin Boyce
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA.
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Zwieniecki MA, Stone HA, Leigh A, Boyce CK, Holbrook NM. Hydraulic design of pine needles: one-dimensional optimization for single-vein leaves. Plant Cell Environ 2006; 29:803-9. [PMID: 17087464 DOI: 10.1111/j.1365-3040.2005.01448.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Single-vein leaves have the simplest hydraulic design possible, yet even this linear water delivery system can be modulated to improve physiological performance. We determined the optimal distribution of transport capacity that minimizes pressure drop per given investment in xylem permeability along the needle for a given length without a change in total water delivery, or maximizes needle length for a given pressure difference between petiole and needle tip. This theory was tested by comparative analysis of the hydraulic design of three pine species that differ in the length of their needles [Pinus palustris (Engl.) Miller, approximately 50 cm; Pinus ponderosa Lawson & Lawson, approximately 20 cm and Pinus rigida Miller, approximately 5 cm]. In all three species, the distribution of hydraulic permeability was similar to that predicted by the optimum solution. The needles of P. palustris showed an almost perfect match between predicted and actual hydraulic optimum solution, providing evidence that vein design is a significant factor in the hydraulic design of pine leaves.
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Affiliation(s)
- Maciej A Zwieniecki
- Arnold Arboretum, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA.
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Boyce CK, Zwieniecki MA, Cody GD, Jacobsen C, Wirick S, Knoll AH, Holbrook NM. Evolution of xylem lignification and hydrogel transport regulation. Proc Natl Acad Sci U S A 2004; 101:17555-8. [PMID: 15574502 PMCID: PMC536047 DOI: 10.1073/pnas.0408024101] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In vascular plants, the polysaccharide-based walls of water-conducting cells are strengthened by impregnation with the polyphenolic polymer lignin. The fine-scale patterning of lignin deposition in water-conducting cells is shown here to vary phylogenetically across vascular plants. The extent to which water transport in xylem cells can be modified in response to changes in the ionic content of xylem sap also is shown to vary in correlation with variation in lignification patterns, consistent with the proposed mechanism for hydraulic response through size change of middle-lamella pectins. This covariation suggests that the fine-scale distribution of hydrophilic polysaccharides and hydrophobic lignin can affect hydraulic as well as mechanical properties, and that the evolutionary diversification of vascular cells thus reflects biochemical as well as morphological innovations evolved to fulfill opposing cell functions of transport and structural support.
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Affiliation(s)
- C Kevin Boyce
- Department of Geophysical Sciences, University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60637, USA.
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Zwieniecki MA, Boyce CK, Holbrook NM. Functional design space of single-veined leaves: role of tissue hydraulic properties in constraining leaf size and shape. Ann Bot 2004; 94:507-13. [PMID: 15319225 PMCID: PMC4242227 DOI: 10.1093/aob/mch173] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Revised: 05/17/2004] [Accepted: 06/18/2004] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS Morphological diversity of leaves is usually quantified with geometrical characters, while in many cases a simple set of biophysical parameters are involved in constraining size and shape. One of the main physiological functions of the leaf is transpiration and thus one can expect that leaf hydraulic parameters can be used to predict potential morphologies, although with the caveat that morphology in turn influences physiological parameters including light interception and boundary layer thickness and thereby heat transfer and net photosynthesis. METHODS An iterative model was used to determine the relative sizes and shapes that are functionally possible for single-veined leaves as defined by their ability to supply the entire leaf lamina with sufficient water to prevent stomatal closure. The model variables include the hydraulic resistances associated with vein axial and radial transport, as well as with water movement through the mesophyll and the leaf surface. KEY RESULTS The four parameters included in the model are sufficient to define a hydraulic functional design space that includes all single-veined leaf shapes found in nature, including scale-, awl- and needle-like morphologies. This exercise demonstrates that hydraulic parameters have dissimilar effects: surface resistance primarily affects leaf size, while radial and mesophyll resistances primarily affect leaf shape. CONCLUSIONS These distinctions between hydraulic parameters, as well as the differential accessibility of different morphologies, might relate to the convergent evolutionary patterns seen in a variety of fossil lineages concerning overall morphology and anatomical detail that frequently have evolved in linear and simple multi-veined leaves.
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Affiliation(s)
- Maciej A Zwieniecki
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave, Cambridge, MA 02138, USA.
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Boyce CK, Hazen RM, Knoll AH. Nondestructive, in situ, cellular-scale mapping of elemental abundances including organic carbon in permineralized fossils. Proc Natl Acad Sci U S A 2001; 98:5970-4. [PMID: 11371632 PMCID: PMC33407 DOI: 10.1073/pnas.101130598] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2001] [Indexed: 11/18/2022] Open
Abstract
The electron microprobe allows elemental abundances to be mapped at the microm scale, but until now high resolution mapping of light elements has been challenging. Modifications of electron microprobe procedure permit fine-scale mapping of carbon. When applied to permineralized fossils, this technique allows simultaneous mapping of organic material, major matrix-forming elements, and trace elements with microm-scale resolution. The resulting data make it possible to test taphonomic hypotheses for the formation of anatomically preserved silicified fossils, including the role of trace elements in the initiation of silica precipitation and in the prevention of organic degradation. The technique allows one to understand the localization of preserved organic matter before undertaking destructive chemical analyses and, because it is nondestructive, offers a potentially important tool for astrobiological investigations of samples returned from Mars or other solar system bodies.
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Affiliation(s)
- C K Boyce
- Botanical Museum, Harvard University, Cambridge, MA 02138, USA.
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