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Drobnitch ST, Kray JA, Gleason SM, Ocheltree TW. Comparative venation costs of monocotyledon and dicotyledon species in the eastern Colorado steppe. PLANTA 2024; 260:2. [PMID: 38761315 DOI: 10.1007/s00425-024-04434-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 05/05/2024] [Indexed: 05/20/2024]
Abstract
MAIN CONCLUSION Leaf vein network cost (total vein surface area per leaf volume) for major veins and vascular bundles did not differ between monocot and dicot species in 21 species from the eastern Colorado steppe. Dicots possessed significantly larger minor vein networks than monocots. Across the tree of life, there is evidence that dendritic vascular transport networks are optimized, balancing maximum speed and integrity of resource delivery with minimal resource investment in transport and infrastructure. Monocot venation, however, is not dendritic, and remains parallel down to the smallest vein orders with no space-filling capillary networks. Given this departure from the "optimized" dendritic network, one would assume that monocots are operating at a significant energetic disadvantage. In this study, we investigate whether monocot venation networks bear significantly greater carbon/construction costs per leaf volume than co-occurring dicots in the same ecosystem, and if so, what physiological or ecological advantage the monocot life form possesses to compensate for this deficit. Given that venation networks could also be optimized for leaf mechanical support or provide herbivory defense, we measured the vascular system of both monocot and dicots at three scales to distinguish between leaf investment in mechanical support (macroscopic vein), total transport and capacitance (vascular bundle), or exclusively water transport (xylem) for both parallel and dendritic venation networks. We observed that vein network cost (total vein surface area per leaf volume) for major veins and vascular bundles was not significantly different between monocot species and dicot species. Dicots, however, possess significantly larger minor vein networks than monocots. The 19 species subjected to gas-exchange measurement in the field displayed a broad range of Amax and but demonstrated no significant relationships with any metric of vascular network size in major or minor vein classes. Given that monocots do not seem to display any leaf hydraulic disadvantage relative to dicots, it remains an important research question why parallel venation (truly parallel, down to the smallest vessels) has not arisen more than once in the history of plant evolution.
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Affiliation(s)
- Sarah Tepler Drobnitch
- Department of Forest and Rangeland Stewardship, Colorado State University, 1472 Campus Delivery, Fort Collins, CO, 80523-1472, USA.
| | - J A Kray
- Rangeland Resources and Systems Research Unit, USDA-ARS, Fort Collins, CO, 80526, USA
| | - Sean M Gleason
- Water Management and Systems Research Unit, USDA-ARS, Fort Collins, CO, USA
| | - Troy W Ocheltree
- Department of Forest and Rangeland Stewardship, Colorado State University, 1472 Campus Delivery, Fort Collins, CO, 80523-1472, USA
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2
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Gu J, Struik PC, Evers JB, Lertngim N, Lin R, Driever SM. Quantifying differences in plant architectural development between hybrid potato (Solanum tuberosum) plants grown from two types of propagules. ANNALS OF BOTANY 2024; 133:365-378. [PMID: 38099505 PMCID: PMC11005760 DOI: 10.1093/aob/mcad194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/13/2023] [Indexed: 04/11/2024]
Abstract
BACKGROUND AND AIMS Plants can propagate generatively and vegetatively. The type of propagation and the resulting propagule can influence the growth of the plants, such as plant architectural development and pattern of biomass allocation. Potato is a species that can reproduce through both types of propagation: through true botanical seeds and seed tubers. The consequences of propagule type on the plant architectural development and biomass partitioning in potatoes are not well known. We quantified architectural differences between plants grown from these two types of propagules from the same genotype, explicitly analysing branching dynamics above and below ground, and related these differences to biomass allocation patterns. METHODS A greenhouse experiment was conducted, using potato plants of the same genotype but grown from two types of propagules: true seeds and seed tubers from a plant grown from true seed (seedling tuber). Architectural traits and biomass allocation to different organs were quantified at four developmental stages. Differences between true-seed-grown and seedling-tuber-grown plants were compared at the whole-plant level and at the level of individual stems and branches, including their number, size and location on the plant. KEY RESULTS A more branched and compact architecture was produced in true-seed-grown plants compared with seedling-tuber-grown plants. The architectural differences between plants grown from true seeds and seedling tubers appeared gradually and were attributed mainly to the divergent temporal-spatial distribution of lateral branches above and below ground on the main axis. The continual production of branches in true-seed-grown plants indicated their indeterminate growth habit, which was also reflected in a slower shift of biomass allocation from above- to below-ground branches, whereas the opposite trend was found in seedling-tuber-grown plants. CONCLUSIONS In true-seed-grown plants, lateral branching was stronger and determined whole-plant architecture and plant function with regard to light interception and biomass production, compared with seedling-tuber-grown plants. This different role of branching indicates that a difference in preference between clonal and sexual reproduction might exist. The divergent branching behaviours in true-seed-grown and seedling-tuber-grown plants might be regulated by the different intensity of apical dominance, which suggests that the control of branching can depend on the propagule type.
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Affiliation(s)
- Jiahui Gu
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK Wageningen, The Netherlands
| | - Paul C Struik
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK Wageningen, The Netherlands
| | - Jochem B Evers
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK Wageningen, The Netherlands
| | - Narawitch Lertngim
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK Wageningen, The Netherlands
| | - Ruokai Lin
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK Wageningen, The Netherlands
| | - Steven M Driever
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK Wageningen, The Netherlands
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Nunes MH, Vaz MC, Camargo JLC, Laurance WF, de Andrade A, Vicentini A, Laurance S, Raumonen P, Jackson T, Zuquim G, Wu J, Peñuelas J, Chave J, Maeda EE. Edge effects on tree architecture exacerbate biomass loss of fragmented Amazonian forests. Nat Commun 2023; 14:8129. [PMID: 38097604 PMCID: PMC10721830 DOI: 10.1038/s41467-023-44004-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 11/27/2023] [Indexed: 12/17/2023] Open
Abstract
Habitat fragmentation could potentially affect tree architecture and allometry. Here, we use ground surveys of terrestrial LiDAR in Central Amazonia to explore the influence of forest edge effects on tree architecture and allometry, as well as forest biomass, 40 years after fragmentation. We find that young trees colonising the forest fragments have thicker branches and architectural traits that optimise for light capture, which result in 50% more woody volume than their counterparts of similar stem size and height in the forest interior. However, we observe a disproportionately lower height in some large trees, leading to a 30% decline in their woody volume. Despite the substantial wood production of colonising trees, the lower height of some large trees has resulted in a net loss of 6.0 Mg ha-1 of aboveground biomass - representing 2.3% of the aboveground biomass of edge forests. Our findings indicate a strong influence of edge effects on tree architecture and allometry, and uncover an overlooked factor that likely exacerbates carbon losses in fragmented forests.
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Affiliation(s)
- Matheus Henrique Nunes
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.
- Department of Geographical Sciences, University of Maryland, College Park, MD, USA.
| | - Marcel Caritá Vaz
- Institute for Environmental Science and Sustainabilty, Wilkes University, Wilkes-Barre, PA, USA
| | - José Luís Campana Camargo
- Ecology Graduate Program, National Institute for Amazonian Research, (INPA), Manaus, Brazil
- Biological Dynamics of Forest Fragments Project (BDFFP) at National Institute for Amazonian Research (INPA), Manaus, Brazil
| | - William F Laurance
- Centre for Tropical Environmental and Sustainability Science, College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Ana de Andrade
- Biological Dynamics of Forest Fragments Project (BDFFP) at National Institute for Amazonian Research (INPA), Manaus, Brazil
| | - Alberto Vicentini
- Biological Dynamics of Forest Fragments Project (BDFFP) at National Institute for Amazonian Research (INPA), Manaus, Brazil
- Coordenação de Pesquisas em Ecologia, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, AM, Brasil
| | - Susan Laurance
- Centre for Tropical Environmental and Sustainability Science, College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Pasi Raumonen
- Computing Sciences, Tampere University, Tampere, Finland
| | - Toby Jackson
- Plant Sciences and Conservation Research Institute, University of Cambridge, Cambridge, United Kingdom
| | - Gabriela Zuquim
- Amazon Research Team, Department of Biology, University of Turku, Turku, Finland
| | - Jin Wu
- School of Biological Sciences and Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong, China
| | - Josep Peñuelas
- CREAF, Cerdanyola del Vallès, Barcelona, Catalonia, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona, Catalonia, Spain
| | - Jérôme Chave
- Laboratoire Evolution et Diversité Biologique, CNRS, UPS, IRD, Université Paul Sabatier, Toulouse, France
| | - Eduardo Eiji Maeda
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.
- Finnish Meteorological Institute, FMI, Helsinki, Finland.
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4
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Desai-Chowdhry P, Brummer AB, Mallavarapu S, Savage VM. Neuronal branching is increasingly asymmetric near synapses, potentially enabling plasticity while minimizing energy dissipation and conduction time. J R Soc Interface 2023; 20:20230265. [PMID: 37669695 PMCID: PMC10480011 DOI: 10.1098/rsif.2023.0265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 08/15/2023] [Indexed: 09/07/2023] Open
Abstract
Neurons' primary function is to encode and transmit information in the brain and body. The branching architecture of axons and dendrites must compute, respond and make decisions while obeying the rules of the substrate in which they are enmeshed. Thus, it is important to delineate and understand the principles that govern these branching patterns. Here, we present evidence that asymmetric branching is a key factor in understanding the functional properties of neurons. First, we derive novel predictions for asymmetric scaling exponents that encapsulate branching architecture associated with crucial principles such as conduction time, power minimization and material costs. We compare our predictions with extensive data extracted from images to associate specific principles with specific biophysical functions and cell types. Notably, we find that asymmetric branching models lead to predictions and empirical findings that correspond to different weightings of the importance of maximum, minimum or total path lengths from the soma to the synapses. These different path lengths quantitatively and qualitatively affect energy, time and materials. Moreover, we generally observe that higher degrees of asymmetric branching-potentially arising from extrinsic environmental cues and synaptic plasticity in response to activity-occur closer to the tips than the soma (cell body).
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Affiliation(s)
- Paheli Desai-Chowdhry
- Department of Computational Medicine, University of California Los Angeles, Los Angeles, CA, USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Samhita Mallavarapu
- Department of Computational Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Van M. Savage
- Department of Computational Medicine, University of California Los Angeles, Los Angeles, CA, USA
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
- Santa Fe Institute, Santa Fe, NM, USA
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5
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Desai-Chowdhry P, Brummer AB, Mallavarapu S, Savage VM. Neuronal Branching is Increasingly Asymmetric Near Synapses, Potentially Enabling Plasticity While Minimizing Energy Dissipation and Conduction Time. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.20.541591. [PMID: 37292687 PMCID: PMC10245708 DOI: 10.1101/2023.05.20.541591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Neurons' primary function is to encode and transmit information in the brain and body. The branching architecture of axons and dendrites must compute, respond, and make decisions while obeying the rules of the substrate in which they are enmeshed. Thus, it is important to delineate and understand the principles that govern these branching patterns. Here, we present evidence that asymmetric branching is a key factor in understanding the functional properties of neurons. First, we derive novel predictions for asymmetric scaling exponents that encapsulate branching architecture associated with crucial principles such as conduction time, power minimization, and material costs. We compare our predictions with extensive data extracted from images to associate specific principles with specific biophysical functions and cell types. Notably, we find that asymmetric branching models lead to predictions and empirical findings that correspond to different weightings of the importance of maximum, minimum, or total path lengths from the soma to the synapses. These different path lengths quantitatively and qualitatively affect energy, time, and materials. Moreover, we generally observe that higher degrees of asymmetric branching- potentially arising from extrinsic environmental cues and synaptic plasticity in response to activity- occur closer to the tips than the soma (cell body).
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6
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Wolfe BT, Detto M, Zhang YJ, Anderson-Teixeira KJ, Brodribb T, Collins AD, Crawford C, Dickman LT, Ely KS, Francisco J, Gurry PD, Hancock H, King CT, Majekobaje AR, Mallett CJ, McDowell NG, Mendheim Z, Michaletz ST, Myers DB, Price TJ, Rogers A, Sack L, Serbin SP, Siddiq Z, Willis D, Wu J, Zailaa J, Wright SJ. Leaves as bottlenecks: The contribution of tree leaves to hydraulic resistance within the soil-plant-atmosphere continuum. PLANT, CELL & ENVIRONMENT 2023; 46:736-746. [PMID: 36564901 DOI: 10.1111/pce.14524] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/12/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Within vascular plants, the partitioning of hydraulic resistance along the soil-to-leaf continuum affects transpiration and its response to environmental conditions. In trees, the fractional contribution of leaf hydraulic resistance (Rleaf ) to total soil-to-leaf hydraulic resistance (Rtotal ), or fRleaf (=Rleaf /Rtotal ), is thought to be large, but this has not been tested comprehensively. We compiled a multibiome data set of fRleaf using new and previously published measurements of pressure differences within trees in situ. Across 80 samples, fRleaf averaged 0.51 (95% confidence interval [CI] = 0.46-0.57) and it declined with tree height. We also used the allometric relationship between field-based measurements of soil-to-leaf hydraulic conductance and laboratory-based measurements of leaf hydraulic conductance to compute the average fRleaf for 19 tree samples, which was 0.40 (95% CI = 0.29-0.56). The in situ technique produces a more accurate descriptor of fRleaf because it accounts for dynamic leaf hydraulic conductance. Both approaches demonstrate the outsized role of leaves in controlling tree hydrodynamics. A larger fRleaf may help stems from loss of hydraulic conductance. Thus, the decline in fRleaf with tree height would contribute to greater drought vulnerability in taller trees and potentially to their observed disproportionate drought mortality.
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Affiliation(s)
- Brett T Wolfe
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
- Smithsonian Tropical Research Institute, Balboa, Republic of Panama
| | - Matteo Detto
- Smithsonian Tropical Research Institute, Balboa, Republic of Panama
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, Maine, USA
| | - Kristina J Anderson-Teixeira
- Smithsonian Tropical Research Institute, Balboa, Republic of Panama
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, Virginia, USA
| | - Tim Brodribb
- School of Natural Sciences, University of Tasmania, Hobart, Australia
| | - Adam D Collins
- Los Alamos National Laboratory, Earth and Environmental Sciences Division, Los Alamos, New Mexico, USA
| | - Chloe Crawford
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - L Turin Dickman
- Los Alamos National Laboratory, Earth and Environmental Sciences Division, Los Alamos, New Mexico, USA
| | - Kim S Ely
- Brookhaven National Laboratory, Environmental and Climate Science Department, Upton, New York, USA
| | - Jessica Francisco
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Preston D Gurry
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Haigan Hancock
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Christopher T King
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Adelodun R Majekobaje
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Christian J Mallett
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Nate G McDowell
- Pacific Northwest National Lab, Atmospheric Sciences and Global Change Division, Richland, Washington, USA
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Zachary Mendheim
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Sean T Michaletz
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Daniel B Myers
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Ty J Price
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Alistair Rogers
- Brookhaven National Laboratory, Environmental and Climate Science Department, Upton, New York, USA
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
| | - Shawn P Serbin
- Brookhaven National Laboratory, Environmental and Climate Science Department, Upton, New York, USA
| | - Zafar Siddiq
- Department of Botany, Government College University, Lahore, Pakistan
| | - David Willis
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Jin Wu
- School of Biological Sciences, Research Area of Ecology and Biodiversity, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Joseph Zailaa
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, Virginia, USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
- School of the Environment, Yale University, New Haven, Connecticut, USA
| | - S Joseph Wright
- Smithsonian Tropical Research Institute, Balboa, Republic of Panama
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7
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Price CA, Drake P, Veneklaas EJ, Renton M. Flow similarity, stochastic branching, and quarter-power scaling in plants. PLANT PHYSIOLOGY 2022; 190:1854-1865. [PMID: 35920766 PMCID: PMC9614476 DOI: 10.1093/plphys/kiac358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
The origin of allometric scaling patterns that are multiples of one-fourth has long fascinated biologists. While not universal, quarter-power scaling relationships are common and have been described in all major clades. Several models have been advanced to explain the origin of such patterns, but questions regarding the discordance between model predictions and empirical data have limited their widespread acceptance. Notable among these is a fractal branching model that predicts power-law scaling of both metabolism and physical dimensions. While a power law is a useful first approximation to some data sets, nonlinear data compilations suggest the possibility of alternative mechanisms. Here, we show that quarter-power scaling can be derived using only the preservation of volume flow rate and velocity as model constraints. Applying our model to land plants, we show that incorporating biomechanical principles and allowing different parts of plant branching networks to be optimized to serve different functions predicts nonlinearity in allometric relationships and helps explain why interspecific scaling exponents covary along a fractal continuum. We also demonstrate that while branching may be a stochastic process, due to the conservation of volume, data may still be consistent with the expectations for a fractal network when one examines sub-trees within a tree. Data from numerous sources at the level of plant shoots, stems, and petioles show strong agreement with our model predictions. This theoretical framework provides an easily testable alternative to current general models of plant metabolic allometry.
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Affiliation(s)
| | - Paul Drake
- School of Biological Sciences, University of Western Australia, Perth, Western Australia 6009, Australia
- School of Agriculture and Environment, University of Western Australia, Perth, Western Australia 6009, Australia
- Centre of Excellence for Climate Change, Woodland and Forest Health, University of Western Australia, Perth, Western Australia 6009, Australia
| | - Erik J Veneklaas
- School of Biological Sciences, University of Western Australia, Perth, Western Australia 6009, Australia
- School of Agriculture and Environment, University of Western Australia, Perth, Western Australia 6009, Australia
- Centre of Excellence for Climate Change, Woodland and Forest Health, University of Western Australia, Perth, Western Australia 6009, Australia
| | - Michael Renton
- School of Biological Sciences, University of Western Australia, Perth, Western Australia 6009, Australia
- School of Agriculture and Environment, University of Western Australia, Perth, Western Australia 6009, Australia
- Centre of Excellence for Climate Change, Woodland and Forest Health, University of Western Australia, Perth, Western Australia 6009, Australia
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8
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Levionnois S, Salmon C, Alméras T, Clair B, Ziegler C, Coste S, Stahl C, González-Melo A, Heinz C, Heuret P. Anatomies, vascular architectures, and mechanics underlying the leaf size-stem size spectrum in 42 Neotropical tree species. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:7957-7969. [PMID: 34390333 DOI: 10.1093/jxb/erab379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
The leaf size-stem size spectrum is one of the main dimensions of plant ecological strategies. Yet the anatomical, mechanical, and hydraulic implications of small versus large shoots are still poorly understood. We investigated 42 tropical rainforest tree species in French Guiana, with a wide range of leaf areas at the shoot level. We quantified the scaling of hydraulic and mechanical constraints with shoot size, estimated as the water potential difference (ΔΨ) and the bending angle (ΔΦ), respectively. We investigated how anatomical tissue area, flexural stiffness and xylem vascular architecture affect such scaling by deviating (or not) from theoretical isometry with shoot size variation. Vessel diameter and conductive path length were found to be allometrically related to shoot size, thereby explaining the independence between ΔΨ and shoot size. Leaf mass per area, stem length, and the modulus of elasticity were allometrically related to shoot size, explaining the independence between ΔΦ and shoot size. Our study also shows that the maintenance of both water supply and mechanical stability across the shoot size range are not in conflict.
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Affiliation(s)
- Sébastien Levionnois
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, 97310 Kourou, France
- UMR AMAP, Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Université de Montpellier, 34000 Montpellier, France
| | - Camille Salmon
- UMR AMAP, Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Université de Montpellier, 34000 Montpellier, France
| | - Tancrède Alméras
- LMGC, CNRS, Université de Montpellier, 34090 Montpellier, France
| | - Bruno Clair
- LMGC, CNRS, Université de Montpellier, 34090 Montpellier, France
| | - Camille Ziegler
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, 97310 Kourou, France
- UMR SILVA, INRAE, Université de Lorraine, 54000 Nancy, France
| | - Sabrina Coste
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, 97310 Kourou, France
| | - Clément Stahl
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, 97310 Kourou, France
| | | | - Christine Heinz
- UMR AMAP, Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Université de Montpellier, 34000 Montpellier, France
| | - Patrick Heuret
- UMR AMAP, Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Université de Montpellier, 34000 Montpellier, France
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9
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Wilkes P, Shenkin A, Disney M, Malhi Y, Bentley LP, Vicari MB. Terrestrial laser scanning to reconstruct branch architecture from harvested branches. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13709] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Phil Wilkes
- Department of Geography University College London London UK
- NERC National Centre for Earth Observation Leicester UK
| | - Alexander Shenkin
- Environmental Change Institute School of Geography and Environment University of Oxford Oxford UK
| | - Mathias Disney
- Department of Geography University College London London UK
- NERC National Centre for Earth Observation Leicester UK
| | - Yadvinder Malhi
- Environmental Change Institute School of Geography and Environment University of Oxford Oxford UK
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10
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Measuring the Contribution of Leaves to the Structural Complexity of Urban Tree Crowns with Terrestrial Laser Scanning. REMOTE SENSING 2021. [DOI: 10.3390/rs13142773] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Trees have a fractal-like branching architecture that determines their structural complexity. We used terrestrial laser scanning technology to study the role of foliage in the structural complexity of urban trees. Forty-five trees of three deciduous species, Gleditsia triacanthos, Quercus macrocarpa, Metasequoia glyptostroboides, were sampled on the Michigan State University campus. We studied their structural complexity by calculating the box-dimension (Db) metric from point clouds generated for the trees using terrestrial laser scanning, during the leaf-on and -off conditions. Furthermore, we artificially defoliated the leaf-on point clouds by applying an algorithm that separates the foliage from the woody material of the trees, and then recalculated the Db metric. The Db of the leaf-on tree point clouds was significantly greater than the Db of the leaf-off point clouds across all species. Additionally, the leaf removal algorithm introduced bias to the estimation of the leaf-removed Db of the G. triacanthos and M. glyptostroboides trees. The index capturing the contribution of leaves to the structural complexity of the study trees (the ratio of the Db of the leaf-on point clouds divided by the Db of the leaf-off point clouds minus one), was negatively correlated with branch surface area and different metrics of the length of paths through the branch network of the trees, indicating that the contribution of leaves decreases as branch network complexity increases. Underestimation of the Db of the G. triacanthos trees, after the artificial leaf removal, was related to maximum branch order. These results enhance our understanding of tree structural complexity by disentangling the contribution of leaves from that of the woody structures. The study also highlighted important methodological considerations for studying tree structure, with and without leaves, from laser-derived point clouds.
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11
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Arseniou G, MacFarlane DW. Fractal dimension of tree crowns explains species functional-trait responses to urban environments at different scales. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02297. [PMID: 33427362 DOI: 10.1002/eap.2297] [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: 02/25/2020] [Revised: 07/20/2020] [Accepted: 10/05/2020] [Indexed: 06/12/2023]
Abstract
The evolution of form and function of trees of diverse species has taken place over hundreds of millions of years, while urban environments are relatively new on an evolutionary time scale, representing a novel set of environmental constraints for trees to respond to. It is important to understand how trees of different species, planted in these anthropogenically-structured urban ecosystems, are responding to them. Many theories have been advanced to understand tree form and function, including several that suggest the fractal-like geometry of trees is a direct reflection of inherent and plastic morphological and physiological traits that govern tree growth and survival. In this research, we analyzed the "fractal dimension" of thousands of tree crowns of many different tree species, growing in different urban environments across the United States, to learn more about the nature of trees and their responses to urban environments at different scales. Our results provide new insights regarding how tree crown fractal dimension relates to balances between hydraulic- and light-capture-related functions (e.g., drought and shade tolerance). Our findings indicate that trees exhibit reduced crown fractal dimension primarily to reduce water loss in hotter cities. More specifically, the intrinsic drought tolerance of the studied species arises from lower surface to volume ratios at both whole-crown and leaf scales, preadapting them to drought stress in urban ecosystems. Needle-leaved species showed a clear trade-off between optimizing the fractal dimension of their crowns for drought vs. shade tolerance. Broad-leaved species showed a fractal crown architecture that responded principally to inherent drought tolerance. Adjusting for the temperature of cities and intrinsic species effects, the fractal dimension of tree crowns was lower in more heavily urbanized areas (with greater paved area or buildings) and due to crowns conflicting with utility wires. With expectations for more urbanization and generally hotter future climates, worldwide, our results add new insights into the physiological ecology of trees in urban environments, which may help humans to provide more hospitable habitats for trees in urbanized areas and to make better decisions about tree selection in urban forest management.
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Affiliation(s)
- Georgios Arseniou
- Department of Forestry, Michigan State University, East Lansing, Michigan, 48824, USA
| | - David W MacFarlane
- Department of Forestry, Michigan State University, East Lansing, Michigan, 48824, USA
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12
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Brummer AB, Lymperopoulos P, Shen J, Tekin E, Bentley LP, Buzzard V, Gray A, Oliveras I, Enquist BJ, Savage VM. Branching principles of animal and plant networks identified by combining extensive data, machine learning and modelling. J R Soc Interface 2021; 18:20200624. [PMID: 33402023 PMCID: PMC7879751 DOI: 10.1098/rsif.2020.0624] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Branching in vascular networks and in overall organismic form is one of the most common and ancient features of multicellular plants, fungi and animals. By combining machine-learning techniques with new theory that relates vascular form to metabolic function, we enable novel classification of diverse branching networks—mouse lung, human head and torso, angiosperm and gymnosperm plants. We find that ratios of limb radii—which dictate essential biologic functions related to resource transport and supply—are best at distinguishing branching networks. We also show how variation in vascular and branching geometry persists despite observing a convergent relationship across organisms for how metabolic rate depends on body mass.
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Affiliation(s)
- Alexander B Brummer
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, CA, USA.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA.,Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | | | - Jocelyn Shen
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Elif Tekin
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, CA, USA.,Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Lisa P Bentley
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
| | - Vanessa Buzzard
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA
| | - Andrew Gray
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | - Imma Oliveras
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
| | - Brian J Enquist
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA.,Santa Fe Institute, Santa Fe, NM, USA
| | - Van M Savage
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, CA, USA.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA.,Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Santa Fe Institute, Santa Fe, NM, USA
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13
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Martin‐Ducup O, Ploton P, Barbier N, Momo Takoudjou S, Mofack G, Kamdem NG, Fourcaud T, Sonké B, Couteron P, Pélissier R. Terrestrial laser scanning reveals convergence of tree architecture with increasingly dominant crown canopy position. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13678] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
| | - Pierre Ploton
- AMAP, IRDCNRSCIRADINRAUniversity of Montpellier Montpellier France
| | - Nicolas Barbier
- AMAP, IRDCNRSCIRADINRAUniversity of Montpellier Montpellier France
| | - Stéphane Momo Takoudjou
- Plant Systematic and Ecology Laboratory Higher Teacher's Training College University of Yaoundé I Yaoundé Cameroon
| | - Gislain Mofack
- Plant Systematic and Ecology Laboratory Higher Teacher's Training College University of Yaoundé I Yaoundé Cameroon
| | - Narcisse Guy Kamdem
- Plant Systematic and Ecology Laboratory Higher Teacher's Training College University of Yaoundé I Yaoundé Cameroon
| | - Thierry Fourcaud
- AMAP, IRDCNRSCIRADINRAUniversity of Montpellier Montpellier France
| | - Bonaventure Sonké
- Plant Systematic and Ecology Laboratory Higher Teacher's Training College University of Yaoundé I Yaoundé Cameroon
| | - Pierre Couteron
- AMAP, IRDCNRSCIRADINRAUniversity of Montpellier Montpellier France
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14
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Uncertainty in Parameterizing Floodplain Forest Friction for Natural Flood Management, Using Remote Sensing. REMOTE SENSING 2020. [DOI: 10.3390/rs12111799] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
One potential Natural Flood Management (NFM) option is floodplain reforestation or manage existing riparian forests, with a view to increasing flow resistance and attenuate flood hydrographs. However, the effectiveness of floodplain forests as resistance agents, during different magnitude overbank floods, has yet to be appropriately parameterized for hydraulic models. Remote sensing offers high-resolution datasets capable of characterizing vegetation structure from a variety of platforms, but they contain uncertainty. For the first time, we demonstrate uncertainty propagation in remote sensing derivations of complex vegetation structure through roughness prediction and floodplain flow for extreme flows and different forest types (young and old Poplar plantations, young and old Pine plantations, and an unmanaged riparian forest). The lowest uncertainties resulted from terrestrial and airborne lidar, where airborne lidar is currently best at defining canopy leaf area, but more research is needed to determine wood area. Mean literature uncertainties in stem density, trunk diameter, wood, and leaf area indices (20, 10, 30, 20%, respectively) resulted in a combined Manning’s n uncertainty from 11–13% to 11–17% at 2 m to 8 m flow depths. This equates to 7–8% roughness uncertainty per 10% combined forest structure uncertainty. Individually, stem density and trunk diameter uncertainties resulted in the largest Manning’s n uncertainty at all flow depths, especially for flow though Pine plantations. For deeper flows, leaf and woody areas become much more important, especially for unmanaged riparian forests with low canopy morphology. Forest structure errors propagated to flow depth demonstrate that even small flows can change by a decimeter, while deeper flows can change by 40 cm or more. For flow depth, errors in canopy structure are deemed more severe in flows depths beyond 4–6 m. This study highlights the need for lower uncertainty in all forest structure components using remote sensing, to improve roughness parameterization and flood modeling for NFM.
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15
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Tracheal branching in ants is area-decreasing, violating a central assumption of network transport models. PLoS Comput Biol 2020; 16:e1007853. [PMID: 32352964 PMCID: PMC7241831 DOI: 10.1371/journal.pcbi.1007853] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 05/21/2020] [Accepted: 04/06/2020] [Indexed: 11/20/2022] Open
Abstract
The structure of tubular transport networks is thought to underlie much of biological regularity, from individuals to ecosystems. A core assumption of transport network models is either area-preserving or area-increasing branching, such that the summed cross-sectional area of all child branches is equal to or greater than the cross-sectional area of their respective parent branch. For insects, the most diverse group of animals, the assumption of area-preserving branching of tracheae is, however, based on measurements of a single individual and an assumption of gas exchange by diffusion. Here we show that ants exhibit neither area-preserving nor area-increasing branching in their abdominal tracheal systems. We find for 20 species of ants that the sum of child tracheal cross-sectional areas is typically less than that of the parent branch (area-decreasing). The radius, rather than the area, of the parent branch is conserved across the sum of child branches. Interpretation of the tracheal system as one optimized for the release of carbon dioxide, while readily catering to oxygen demand, explains the branching pattern. Our results, together with widespread demonstration that gas exchange in insects includes, and is often dominated by, convection, indicate that for generality, network transport models must include consideration of systems with different architectures. A fundamental assumption of models of the transport of substances through networks of tubes, such as circulatory systems in animals and vascular systems in plants, is that the total cross-sectional area of the tubes remains constant irrespective of the branching level, or that it increases slightly in the direction from the largest to the smallest tubes. One large tube should have the same or a slightly smaller area than the sum of the next two tubes after a branching. The assumption of such a pattern underpins one of biology’s most influential ideas–the metabolic theory of ecology. Surprisingly, the assumption has never been systematically examined for insects–the planet’s most diverse group of animals which deliver oxygen to and remove carbon dioxide from their bodies using a network of tubes known as tracheae. Until recently, it has been technologically very challenging to do so. Here, we use x-ray synchrotron tomography to overcome this challenge. We show that tracheal branching in 20 species of ants does not follow this pattern. Rather, cross-sectional area reduces in an inwards direction. We then use modelling to show that such a pattern facilitates outward CO2 release, a process more challenging for insects than moving oxygen inwards. Our work suggests that much still needs to be done to understand the fundamental assumptions underlying network transport models and how they apply more generally across life–especially in the context of why metabolic rate scales with body size.
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16
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Conn A, Chandrasekhar A, van Rongen M, Leyser O, Chory J, Navlakha S. Network trade-offs and homeostasis in Arabidopsis shoot architectures. PLoS Comput Biol 2019; 15:e1007325. [PMID: 31509526 PMCID: PMC6738579 DOI: 10.1371/journal.pcbi.1007325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 08/08/2019] [Indexed: 12/02/2022] Open
Abstract
Understanding the optimization objectives that shape shoot architectures remains a critical problem in plant biology. Here, we performed 3D scanning of 152 Arabidopsis shoot architectures, including wildtype and 10 mutant strains, and we uncovered a design principle that describes how architectures make trade-offs between competing objectives. First, we used graph-theoretic analysis to show that Arabidopsis shoot architectures strike a Pareto optimal that can be captured as maximizing performance in transporting nutrients and minimizing costs in building the architecture. Second, we identify small sets of genes that can be mutated to shift the weight prioritizing one objective over the other. Third, we show that this prioritization weight feature is significantly less variable across replicates of the same genotype compared to other common plant traits (e.g., number of rosette leaves, total volume occupied). This suggests that this feature is a robust descriptor of a genotype, and that local variability in structure may be compensated for globally in a homeostatic manner. Overall, our work provides a framework to understand optimization trade-offs made by shoot architectures and provides evidence that these trade-offs can be modified genetically, which may aid plant breeding and selection efforts. In both engineered and biological systems, there is often no single structure that performs optimally on all tasks. For example, a transport system that can very quickly shuttle people to and from work will often not be very cheap to build, and vice-versa. Thus, trade-offs are born, and it is natural to ask how well evolution has resolved trade-offs between competing tasks. Here, we use 3D laser scanning and network analysis to show that Arabidopsis plant architectures make Pareto optimal trade-offs, which means that improving upon one task requires a sacrifice in the other task. In other words, an architecture that performs better on both tasks cannot be built. We also identify a small set of genes that can change how the architecture prioritizes one task versus the other, which may allow for better crop design in the future. Finally, we show that two replicate architectures that look visually diverse (e.g., variation in size, number of leaves, number of branches, etc.) often prioritize each task similarly. This suggests that despite local variability in the architecture, there may be a homeostatic drive to maintain globally balanced trade-offs.
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Affiliation(s)
- Adam Conn
- Integrative Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Arjun Chandrasekhar
- Integrative Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Martin van Rongen
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Ottoline Leyser
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Joanne Chory
- Howard Hughes Medical Institute and Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Saket Navlakha
- Integrative Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, United States of America
- * E-mail:
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17
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O'Leary BM, Asao S, Millar AH, Atkin OK. Core principles which explain variation in respiration across biological scales. THE NEW PHYTOLOGIST 2019; 222:670-686. [PMID: 30394553 DOI: 10.1111/nph.15576] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 10/18/2018] [Indexed: 05/02/2023]
Abstract
Contents Summary 670 I. Introduction 671 II. Principle 1 - Plant respiration performs three distinct functions 673 III. Principle 2 - Metabolic pathway flexibility underlies plant respiratory performance 676 IV. Principle 3 - Supply and demand interact over time to set plant respiration rate 677 V. Principle 4 - Plant respiratory acclimation involves adjustments in enzyme capacities 679 VI. Principle 5 - Respiration is a complex trait that helps to define, and is impacted by, plant lifestyle strategies 680 VII. Future directions 680 Acknowledgements 682 References 682 SUMMARY: Respiration is a core biological process that has important implications for the biochemistry, physiology, and ecology of plants. The study of plant respiration is thus conducted from several different perspectives by a range of scientific disciplines with dissimilar objectives, such as metabolic engineering, crop breeding, and climate-change modelling. One aspect in common among the different objectives is a need to understand and quantify the variation in respiration across scales of biological organization. The central tenet of this review is that different perspectives on respiration can complement each other when connected. To better accommodate interdisciplinary thinking, we identify distinct mechanisms which encompass the variation in respiratory rates and functions across biological scales. The relevance of these mechanisms towards variation in plant respiration are explained in the context of five core principles: (1) respiration performs three distinct functions; (2) metabolic pathway flexibility underlies respiratory performance; (3) supply and demand interact over time to set respiration rates; (4) acclimation involves adjustments in enzyme capacities; and (5) respiration is a complex trait that helps to define, and is impacted by, plant lifestyle strategies. We argue that each perspective on respiration rests on these principles to varying degrees and that broader appreciation of how respiratory variation occurs can unite research across scales.
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Affiliation(s)
- Brendan M O'Leary
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, University of Western Australia, Perth, WA, 6009, Australia
| | - Shinichi Asao
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
| | - A Harvey Millar
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, University of Western Australia, Perth, WA, 6009, Australia
| | - Owen K Atkin
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
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18
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Bruy D, Hattermann T, Barrabé L, Mouly A, Barthélémy D, Isnard S. Evolution of Plant Architecture, Functional Diversification and Divergent Evolution in the Genus Atractocarpus (Rubiaceae) for New Caledonia. FRONTIERS IN PLANT SCIENCE 2018; 9:1775. [PMID: 30564258 PMCID: PMC6288547 DOI: 10.3389/fpls.2018.01775] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 11/15/2018] [Indexed: 05/29/2023]
Abstract
The diversification of ecological roles and related adaptations in closely related species within a lineage is one of the most important processes linking plant evolution and ecology. Plant architecture offers a robust framework to study these processes as it can highlight how plant structure influences plant diversification and ecological strategies. We investigated a case of gradual evolution of branching architecture in Atractocarpus spp. (Rubiaceae), forming a monophyletic group in New Caledonia that has diversified rapidly, predominantly in rainforest understory habitats. We used a transdisciplinary approach to depict architectural variations and revealed multiple evolutionary transitions from a branched (Stone's architectural model) to a monocaulous habit (Corner's architectural model), which involved the functional reduction of branches into inflorescences. We propose an integrative functional index that assesses branching incidence on functional traits influencing both assimilation and exploration functions. We showed that architectural transitions correlate with ecologically important functional traits. Variation in ecologically important traits among closely relatives, as supported by the architectural analysis, is suggestive of intense competition that favored divergence among locally coexisting species. We propose that Pleistocene climatic fluctuations causing expansion and contraction of rainforest could also have offered ecological opportunities for colonizers in addition to the process of divergent evolution.
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Affiliation(s)
- David Bruy
- AMAP, IRD, CIRAD, CNRS, INRA, Université de Montpellier, Montpellier, France
- AMAP, IRD, Herbier de Nouméa, Nouméa, New Caledonia
| | - Tom Hattermann
- AMAP, IRD, CIRAD, CNRS, INRA, Université de Montpellier, Montpellier, France
- AMAP, IRD, Herbier de Nouméa, Nouméa, New Caledonia
| | - Laure Barrabé
- Endemia, Plant Red List Authority, Nouméa, New Caledonia
| | - Arnaud Mouly
- Laboratoire Chrono-Environnement UMR 6249 CNRS, Université Bourgogne Franche-Comté, Besançon, France
- Jardin Botanique de la Ville de Besançon et de l'Université de Franche-Comté, Besançon, France
| | - Daniel Barthélémy
- AMAP, IRD, CIRAD, CNRS, INRA, Université de Montpellier, Montpellier, France
- CIRAD, UMR AMAP, Montpellier, France
| | - Sandrine Isnard
- AMAP, IRD, CIRAD, CNRS, INRA, Université de Montpellier, Montpellier, France
- AMAP, IRD, Herbier de Nouméa, Nouméa, New Caledonia
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19
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The arrangement of lateral veins along the midvein of leaves is not related to leaf phyllotaxis. Sci Rep 2018; 8:16417. [PMID: 30401940 PMCID: PMC6219558 DOI: 10.1038/s41598-018-34772-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 10/25/2018] [Indexed: 11/08/2022] Open
Abstract
Positions of leaves along a stem usually adhere to a genetically determined, species-specific pattern known as a leaf phyllotaxis. We investigated whether the arrangement of lateral secondary veins along primary midveins adhered to a species-specific pattern that resembled an alternate or opposite phyllotaxis. We analyzed the venation of temperate dicotyledonous species from different taxonomic groups and chose 18 woody and 12 herbaceous species that have reticulated leaf venation. The arrangement of the lateral veins was neither alternate nor opposite for any of the species. Lateral vein arrangements were instead mixtures of symmetric and asymmetric patterns. Our results show that lateral vein arrangements are related neither to stem-level leaf phyllotaxis (alternate vs. opposite) nor to life form (woody vs. herbaceous). Our results are therefore generally consistent with the canalization hypothesis that the locations of lateral veins are not completely specified genetically prior to leaf formation.
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20
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Hellström L, Carlsson L, Falster DS, Westoby M, Brännström Å. Branch Thinning and the Large-Scale, Self-Similar Structure of Trees. Am Nat 2018; 192:E37-E47. [PMID: 29897799 DOI: 10.1086/697429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Branch formation in trees has an inherent tendency toward exponential growth, but exponential growth in the number of branches cannot continue indefinitely. It has been suggested that trees balance this tendency toward expansion by also losing branches grown in previous growth cycles. Here, we present a model for branch formation and branch loss during ontogeny that builds on the phenomenological assumption of a branch carrying capacity. The model allows us to derive approximate analytical expressions for the number of tips on a branch, the distribution of growth modules within a branch, and the rate and size distribution of tree wood litter produced. Although limited availability of data makes empirical corroboration challenging, we show that our model can fit field observations of red maple (Acer rubrum) and note that the age distribution of discarded branches predicted by our model is qualitatively similar to an empirically observed distribution of dead and abscised branches of balsam poplar (Populus balsamifera). By showing how a simple phenomenological assumption-that the number of branches a tree can maintain is limited-leads directly to predictions on branching structure and the rate and size distribution of branch loss, these results potentially enable more explicit modeling of woody tissues in ecosystems worldwide, with implications for the buildup of flammable fuel, nutrient cycling, and understanding of plant growth.
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21
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Brym ZT, Ernest SM. Process-based allometry describes the influence of management on orchard tree aboveground architecture. PeerJ 2018; 6:e4949. [PMID: 29900077 PMCID: PMC5995097 DOI: 10.7717/peerj.4949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/20/2018] [Indexed: 11/20/2022] Open
Abstract
We evaluated allometric relationships in length, diameter, and mass of branches for two variably managed orchard tree species (tart cherry, Prunus cerasus; apple, Malus spp.). The empirically estimated allometric exponents (a) of the orchard trees were described in the context of two processed-based allometry models that make predictions for a: the West, Brown and Enquist fractal branching model (WBE) and the recently introduced Flow Similarity model (FS). These allometric models make predictions about relationships in plant morphology (e.g., branch mass, diameter, length, volume, surface area) based on constraints imposed on plant growth by physical and physiological processes. We compared our empirical estimates of a to the model predictions to interpret the physiological implications of pruning and management in orchard systems. Our study found strong allometric relationships among the species and individuals studied with limited agreement with the expectations of either model. The 8/3-power law prediction of the mass ∼ diameter relationship by the WBE, indicative of biomechanical limitations, was marginally supported by this study. Length-including allometric relationships deviated from predictions of both models, but shift toward the expectation of flow similarity. In this way, managed orchard trees deviated from strict adherence to the idealized expectations of the models, but still fall within the range of model expectations in many cases despite intensive management.
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Affiliation(s)
- Zachary T. Brym
- Tropical Research and Education Center, University of Florida, Homestead, FL, United States of America
| | - S.K. Morgan Ernest
- Wildlife Ecology and Conservation Department, University of Florida, Gainesville, FL, United States of America
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22
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Malhi Y, Jackson T, Patrick Bentley L, Lau A, Shenkin A, Herold M, Calders K, Bartholomeus H, Disney MI. New perspectives on the ecology of tree structure and tree communities through terrestrial laser scanning. Interface Focus 2018; 8:20170052. [PMID: 29503728 PMCID: PMC5829190 DOI: 10.1098/rsfs.2017.0052] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2017] [Indexed: 11/12/2022] Open
Abstract
Terrestrial laser scanning (TLS) opens up the possibility of describing the three-dimensional structures of trees in natural environments with unprecedented detail and accuracy. It is already being extensively applied to describe how ecosystem biomass and structure vary between sites, but can also facilitate major advances in developing and testing mechanistic theories of tree form and forest structure, thereby enabling us to understand why trees and forests have the biomass and three-dimensional structure they do. Here we focus on the ecological challenges and benefits of understanding tree form, and highlight some advances related to capturing and describing tree shape that are becoming possible with the advent of TLS. We present examples of ongoing work that applies, or could potentially apply, new TLS measurements to better understand the constraints on optimization of tree form. Theories of resource distribution networks, such as metabolic scaling theory, can be tested and further refined. TLS can also provide new approaches to the scaling of woody surface area and crown area, and thereby better quantify the metabolism of trees. Finally, we demonstrate how we can develop a more mechanistic understanding of the effects of avoidance of wind risk on tree form and maximum size. Over the next few years, TLS promises to deliver both major empirical and conceptual advances in the quantitative understanding of trees and tree-dominated ecosystems, leading to advances in understanding the ecology of why trees and ecosystems look and grow the way they do.
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Affiliation(s)
- Yadvinder Malhi
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford, Oxon OX1 3QY, UK
| | - Tobias Jackson
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford, Oxon OX1 3QY, UK
| | - Lisa Patrick Bentley
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford, Oxon OX1 3QY, UK.,Department of Biology, Sonoma State University, 1801 East Cotati Avenue, Rohnert Park, CA 94928, USA
| | - Alvaro Lau
- Laboratory of Geo-Information Science and Remote Sensing, Wageningen University and Research, Droevendaalsesteeg 3, 6708 PB Wageningen, The Netherlands.,Center for International Forestry Research (CIFOR), Situ Gede, Sindang Barang, Bogor 16680, Indonesia
| | - Alexander Shenkin
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford, Oxon OX1 3QY, UK
| | - Martin Herold
- Laboratory of Geo-Information Science and Remote Sensing, Wageningen University and Research, Droevendaalsesteeg 3, 6708 PB Wageningen, The Netherlands
| | - Kim Calders
- Earth Observation, Climate and Optical Group, National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, UK.,Department of Geography, University College London, Gower Street, London WC1E 6BT, UK
| | - Harm Bartholomeus
- Laboratory of Geo-Information Science and Remote Sensing, Wageningen University and Research, Droevendaalsesteeg 3, 6708 PB Wageningen, The Netherlands
| | - Mathias I Disney
- Department of Geography, University College London, Gower Street, London WC1E 6BT, UK.,NERC National Centre for Earth Observation (NCEO)
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23
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Berry ZC, Looker N, Holwerda F, Gómez Aguilar LR, Ortiz Colin P, González Martínez T, Asbjornsen H. Why size matters: the interactive influences of tree diameter distribution and sap flow parameters on upscaled transpiration. TREE PHYSIOLOGY 2018; 38:263-275. [PMID: 29040787 DOI: 10.1093/treephys/tpx124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 09/13/2017] [Indexed: 06/07/2023]
Abstract
In stands with a broad range of diameters, a small number of very large trees can disproportionately influence stand basal area and transpiration (Et). Sap flow-based Et estimates may be particularly sensitive to large trees due to nonlinear relationships between tree-level water use (Q) and tree diameter at breast height (DBH). Because Q is typically predicted on the basis of DBH and sap flow rates measured in a subset of trees and then summed to obtain Et, we assessed the relative importance of DBH and sap flow variables (sap velocity, Vs, and sapwood depth, Rs) in determining the magnitude of Et and its dependence on large trees in a tropical montane forest ecosystem. Specifically, we developed a data-driven simulation framework to vary the relationship between DBH and Vs and stand DBH distribution and then calculate Q, Et and the proportion of Et contributed by the largest tree in each stand. Our results demonstrate that variation in how Rs is determined in the largest trees can alter estimates up to 26% of Et while variation in how Vs is determined can vary results by up to 132%. Taken together, these results highlight a great need to expand our understanding of water transport in large trees as this hinders our ability to predict water fluxes accurately from stand to catchment scales.
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Affiliation(s)
- Z Carter Berry
- Department of Natural Resources and the Environment, The University of New Hampshire, 46 College Road, Durham, NH 03824, USA
| | - Nathaniel Looker
- Department of Soil Water and Climate, The University of Minnesota-Twin Cities, 1991 Upper Buford Circle, St Paul, MN 55108, USA
| | - Friso Holwerda
- Universidad Nacional Autónoma de México, Av. Universidad 3000, Ciudad de México D.F., 04510, Mexico
| | | | - Perla Ortiz Colin
- Instituto de Ecologia, Carretera antigua a Coatepec, Xalapa, Veracruz, 91070, Mexico
| | - Teresa González Martínez
- Universidad Nacional Autónoma de México, Av. Universidad 3000, Ciudad de México D.F., 04510, Mexico
| | - Heidi Asbjornsen
- Department of Natural Resources and the Environment, The University of New Hampshire, 46 College Road, Durham, NH 03824, USA
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Conn A, Pedmale UV, Chory J, Navlakha S. High-Resolution Laser Scanning Reveals Plant Architectures that Reflect Universal Network Design Principles. Cell Syst 2017; 5:53-62.e3. [PMID: 28750198 DOI: 10.1016/j.cels.2017.06.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 03/15/2017] [Accepted: 06/29/2017] [Indexed: 11/19/2022]
Abstract
Transport networks serve critical functions in biological and engineered systems, and yet their design requires trade-offs between competing objectives. Due to their sessile lifestyle, plants need to optimize their architecture to efficiently acquire and distribute resources while also minimizing costs in building infrastructure. To understand how plants resolve this design trade-off, we used high-precision three-dimensional laser scanning to map the architectures of tomato, tobacco, or sorghum plants grown in several environmental conditions and through multiple developmental time points, scanning in total 505 architectures from 37 plants. Using a graph-theoretic algorithm that we developed to evaluate design strategies, we find that plant architectures lie along the Pareto front between two simple length-based objectives-minimizing total branch length and minimizing nutrient transport distance-thereby conferring a selective fitness advantage for plant transport processes. The location along the Pareto front can distinguish among species and conditions, suggesting that during evolution, natural selection may employ common network design principles despite different optimization trade-offs.
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Affiliation(s)
- Adam Conn
- Integrative Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Ullas V Pedmale
- Howard Hughes Medical Institute and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Joanne Chory
- Howard Hughes Medical Institute and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Saket Navlakha
- Integrative Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.
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Conn A, Pedmale UV, Chory J, Stevens CF, Navlakha S. A Statistical Description of Plant Shoot Architecture. Curr Biol 2017; 27:2078-2088.e3. [PMID: 28690115 PMCID: PMC6130893 DOI: 10.1016/j.cub.2017.06.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 04/20/2017] [Accepted: 06/02/2017] [Indexed: 12/22/2022]
Abstract
Plant architectures can be characterized statistically by their spatial density function, which specifies the probability of finding a branch at each location in the territory occupied by a plant. Using high-precision 3D scanning, we analyzed 557 plant shoot architectures, representing three species, grown across three to five environmental conditions, and through 20-30 developmental time points. We found two elegant properties in the spatial density functions of these architectures: all functions could be nearly modified in one direction without affecting the density in orthogonal directions (called "separability"), and all functions shared the same underlying shape, aside from stretching and compression (called "self-similarity"). Surprisingly, despite their striking visual diversity, we discovered that all architectures could be described as variations on a single underlying function: a Gaussian density function truncated at roughly two SDs. We also observed systematic variation in the spatial density functions across species, growth conditions, and time, which suggests functional specialization despite following the same general design form.
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Affiliation(s)
- Adam Conn
- Integrative Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Ullas V Pedmale
- Howard Hughes Medical Institute and Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Joanne Chory
- Howard Hughes Medical Institute and Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Charles F Stevens
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Saket Navlakha
- Integrative Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
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Pratt RB, Jacobsen AL. Conflicting demands on angiosperm xylem: Tradeoffs among storage, transport and biomechanics. PLANT, CELL & ENVIRONMENT 2017; 40:897-913. [PMID: 27861981 DOI: 10.1111/pce.12862] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 10/31/2016] [Indexed: 05/26/2023]
Abstract
The secondary xylem of woody plants transports water mechanically supports the plant body and stores resources. These three functions are interdependent giving rise to tradeoffs in function. Understanding the relationships among these functions and their structural basis forms the context in which to interpret xylem evolution. The tradeoff between xylem transport efficiency and safety from cavitation has been carefully examined with less focus on other functions, particularly storage. Here, we synthesize data on all three xylem functions in angiosperm branch xylem in the context of tradeoffs. Species that have low safety and efficiency, examined from a resource economics perspective, are predicted to be adapted for slow resource acquisition and turnover as characterizes some environments. Tradeoffs with water storage primarily arise because of differences in fibre traits, while tradeoffs in carbohydrate storage are driven by parenchyma content of tissue. We find support for a tradeoff between safety from cavitation and storage of both water and starch in branch xylem tissue and between water storage capacity and mechanical strength. Living fibres may facilitate carbohydrate storage without compromising mechanical strength. The division of labour between different xylem cell types allows for considerable functional and structural diversity at multiple scales.
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Affiliation(s)
- R Brandon Pratt
- California State University, Bakersfield, Department of Biology, Bakersfield, CA, 93311, USA
| | - Anna L Jacobsen
- California State University, Bakersfield, Department of Biology, Bakersfield, CA, 93311, USA
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A general model for metabolic scaling in self-similar asymmetric networks. PLoS Comput Biol 2017; 13:e1005394. [PMID: 28319153 PMCID: PMC5378416 DOI: 10.1371/journal.pcbi.1005394] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 04/03/2017] [Accepted: 02/01/2017] [Indexed: 11/19/2022] Open
Abstract
How a particular attribute of an organism changes or scales with its body size is known as an allometry. Biological allometries, such as metabolic scaling, have been hypothesized to result from selection to maximize how vascular networks fill space yet minimize internal transport distances and resistances. The West, Brown, Enquist (WBE) model argues that these two principles (space-filling and energy minimization) are (i) general principles underlying the evolution of the diversity of biological networks across plants and animals and (ii) can be used to predict how the resulting geometry of biological networks then governs their allometric scaling. Perhaps the most central biological allometry is how metabolic rate scales with body size. A core assumption of the WBE model is that networks are symmetric with respect to their geometric properties. That is, any two given branches within the same generation in the network are assumed to have identical lengths and radii. However, biological networks are rarely if ever symmetric. An open question is: Does incorporating asymmetric branching change or influence the predictions of the WBE model? We derive a general network model that relaxes the symmetric assumption and define two classes of asymmetrically bifurcating networks. We show that asymmetric branching can be incorporated into the WBE model. This asymmetric version of the WBE model results in several theoretical predictions for the structure, physiology, and metabolism of organisms, specifically in the case for the cardiovascular system. We show how network asymmetry can now be incorporated in the many allometric scaling relationships via total network volume. Most importantly, we show that the 3/4 metabolic scaling exponent from Kleiber’s Law can still be attained within many asymmetric networks. We present a model for incorporating geometrically asymmetric branching into biological resource distribution networks. Our work shows how space-filling and fluid flow principles constrain allowed branching morphologies within the context of our model. Simultaneously, we demonstrate that there is a wide range of asymmetrically branching network architectures that still give rise to 3/4 metabolic scaling exponents.
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Koyama K, Yamamoto K, Ushio M. A lognormal distribution of the lengths of terminal twigs on self-similar branches of elm trees. Proc Biol Sci 2017; 284:20162395. [PMID: 28053062 PMCID: PMC5247503 DOI: 10.1098/rspb.2016.2395] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/05/2016] [Indexed: 11/12/2022] Open
Abstract
Lognormal distributions and self-similarity are characteristics associated with a wide range of biological systems. The sequential breakage model has established a link between lognormal distributions and self-similarity and has been used to explain species abundance distributions. To date, however, there has been no similar evidence in studies of multicellular organismal forms. We tested the hypotheses that the distribution of the lengths of terminal stems of Japanese elm trees (Ulmus davidiana), the end products of a self-similar branching process, approaches a lognormal distribution. We measured the length of the stem segments of three elm branches and obtained the following results: (i) each occurrence of branching caused variations or errors in the lengths of the child stems relative to their parent stems; (ii) the branches showed statistical self-similarity; the observed error distributions were similar at all scales within each branch and (iii) the multiplicative effect of these errors generated variations of the lengths of terminal twigs that were well approximated by a lognormal distribution, although some statistically significant deviations from strict lognormality were observed for one branch. Our results provide the first empirical evidence that statistical self-similarity of an organismal form generates a lognormal distribution of organ sizes.
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Affiliation(s)
- Kohei Koyama
- Department of Life Science and Agriculture, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro 080-8555, Japan
| | - Ken Yamamoto
- Department of Physics, Faculty of Science and Engineering, Chuo University, Bunkyo, Tokyo 112-8551, Japan
| | - Masayuki Ushio
- Department of Environmental Solution Technology, Faculty of Science and Technology, Ryukoku University, 1-5 Yokotani, Seta Oe-cho, Otsu 520-2194, Japan
- Joint Research Center for Science and Technology, Ryukoku University, 1-5 Yokotani, Seta Oe-cho, Otsu 520-2194, Japan
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29
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A predictive nondestructive model for the covariation of tree height, diameter, and stem volume scaling relationships. Sci Rep 2016; 6:31008. [PMID: 27553773 PMCID: PMC4995560 DOI: 10.1038/srep31008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/11/2016] [Indexed: 11/24/2022] Open
Abstract
Metabolic scaling theory (MST) posits that the scaling exponents among plant height H, diameter D, and biomass M will covary across phyletically diverse species. However, the relationships between scaling exponents and normalization constants remain unclear. Therefore, we developed a predictive model for the covariation of H, D, and stem volume V scaling relationships and used data from Chinese fir (Cunninghamia lanceolata) in Jiangxi province, China to test it. As predicted by the model and supported by the data, normalization constants are positively correlated with their associated scaling exponents for D vs. V and H vs. V, whereas normalization constants are negatively correlated with the scaling exponents of H vs. D. The prediction model also yielded reliable estimations of V (mean absolute percentage error = 10.5 ± 0.32 SE across 12 model calibrated sites). These results (1) support a totally new covariation scaling model, (2) indicate that differences in stem volume scaling relationships at the intra-specific level are driven by anatomical or ecophysiological responses to site quality and/or management practices, and (3) provide an accurate non-destructive method for predicting Chinese fir stem volume.
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Swetnam TL, O’Connor CD, Lynch AM. Tree Morphologic Plasticity Explains Deviation from Metabolic Scaling Theory in Semi-Arid Conifer Forests, Southwestern USA. PLoS One 2016; 11:e0157582. [PMID: 27391084 PMCID: PMC4938440 DOI: 10.1371/journal.pone.0157582] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 06/01/2016] [Indexed: 11/20/2022] Open
Abstract
A significant concern about Metabolic Scaling Theory (MST) in real forests relates to consistent differences between the values of power law scaling exponents of tree primary size measures used to estimate mass and those predicted by MST. Here we consider why observed scaling exponents for diameter and height relationships deviate from MST predictions across three semi-arid conifer forests in relation to: (1) tree condition and physical form, (2) the level of inter-tree competition (e.g. open vs closed stand structure), (3) increasing tree age, and (4) differences in site productivity. Scaling exponent values derived from non-linear least-squares regression for trees in excellent condition (n = 381) were above the MST prediction at the 95% confidence level, while the exponent for trees in good condition were no different than MST (n = 926). Trees that were in fair or poor condition, characterized as diseased, leaning, or sparsely crowned had exponent values below MST predictions (n = 2,058), as did recently dead standing trees (n = 375). Exponent value of the mean-tree model that disregarded tree condition (n = 3,740) was consistent with other studies that reject MST scaling. Ostensibly, as stand density and competition increase trees exhibited greater morphological plasticity whereby the majority had characteristically fair or poor growth forms. Fitting by least-squares regression biases the mean-tree model scaling exponent toward values that are below MST idealized predictions. For 368 trees from Arizona with known establishment dates, increasing age had no significant impact on expected scaling. We further suggest height to diameter ratios below MST relate to vertical truncation caused by limitation in plant water availability. Even with environmentally imposed height limitation, proportionality between height and diameter scaling exponents were consistent with the predictions of MST.
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Affiliation(s)
- Tyson L. Swetnam
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, United States of America
| | - Christopher D. O’Connor
- United States Forest Service, Rocky Mountain Research Station, Missoula, MT, United States of America
| | - Ann M. Lynch
- United States Forest Service, Rocky Mountain Research Station, Missoula, MT, United States of America
- Laboratory of Tree Ring Research, University of Arizona, Tucson, AZ, United States of America
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31
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Zhang Y, Li Y, Xie JB. Fixed allocation patterns, rather than plasticity, benefit recruitment and recovery from drought in seedlings of a desert shrub. AOB PLANTS 2016; 8:plw020. [PMID: 27073036 PMCID: PMC4866650 DOI: 10.1093/aobpla/plw020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 03/27/2016] [Indexed: 06/05/2023]
Abstract
The response of plants to drought is controlled by the interaction between physiological regulation and morphological adjustment. Although recent studies have highlighted the long-term morphological acclimatization of plants to drought, there is still debate on how plant biomass allocation patterns respond to drought. In this study, we performed a greenhouse experiment with first-year seedlings of a desert shrub in control, drought and re-water treatments, to examine their physiological and morphological traits during drought and subsequent recovery. We found that (i) biomass was preferentially allocated to roots along a fixed allometric trajectory throughout the first year of development, irrespective of the variation in water availability; and (ii) this fixed biomass allocation pattern benefited the post-drought recovery. These results suggest that, in a stressful environment, natural selection has favoured a fixed biomass allocation pattern rather than plastic responses to environmental variation. The fixed 'preferential allocation to root' biomass suggests that roots may play a critical role in determining the fate of this desert shrub during prolonged drought. As the major organ for resource acquisition and storage, how the root system functions during drought requires further investigation.
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Affiliation(s)
- Yao Zhang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi, Xinjiang 830011, PR China University of Chinese Academy of Sciences, 19A, Yu-Quan Road, Beijing 100039, PR China
| | - Yan Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi, Xinjiang 830011, PR China
| | - Jiang-Bo Xie
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi, Xinjiang 830011, PR China College of Life Science, Shihezi University, Shihezi 832000, PR China
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32
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Franceschini T, Martin-Ducup O, Schneider R. Allometric exponents as a tool to study the influence of climate on the trade-off between primary and secondary growth in major north-eastern American tree species. ANNALS OF BOTANY 2016; 117:551-63. [PMID: 26975315 PMCID: PMC4840475 DOI: 10.1093/aob/mcw003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/18/2015] [Accepted: 11/27/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND AND AIMS Trees invest in both primary (e.g. height) and secondary (e.g. diameter) growth. The trade-off between these investments varies between species and changes with the tree growing environment. To better establish this trade-off, readily available allometric exponents relating height to diameter at breast height (γ(h,dbh)) and stem volume to diameter at breast height (α(v,dbh)) were simultaneously studied. METHODS Allometric exponents α(v,dbh) and γ(h,dbh) were obtained from 8893 individual tree stem analyses from two broadleaved species (Betula papyrifera, Populus tremuloides) and four conifers (Picea glauca, Picea mariana, Pinus banksiana, Abies balsamea) in the temperate and boreal forests of the province of Quebec, Canada. α(v,dbh) and γ(h,dbh) were related to tree age, stand density index (SDI), and mean temperature (TGS) and total precipitation (PGS) of the growing season. KEY RESULTS α(v,dbh) and γ(h,dbh) were found to be invariant with PGS and positively related to SDI and TGS for all species except Pinus banksiana. The parameter values associated with SDI and TGS were of higher value for conifers than for broadleaved species. CONCLUSIONS This suggests that conifers and broadleaved species have different growth patterns. This could be explained by their different mode of development, the conifer species having a stronger apical dominance than broadleaved species. Such results could be further considered in allocation studies to quantify future carbon stocks in managed forests.
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Affiliation(s)
- T Franceschini
- Chaire de recherche sur la forêt habitée, Département de biologie, chimie et géographie, Université du Québec à Rimouski (UQAR), 300 allée des Ursulines, Rimouski (Québec), G5L 3A1, Canada
| | - O Martin-Ducup
- Chaire de recherche sur la forêt habitée, Département de biologie, chimie et géographie, Université du Québec à Rimouski (UQAR), 300 allée des Ursulines, Rimouski (Québec), G5L 3A1, Canada
| | - R Schneider
- Chaire de recherche sur la forêt habitée, Département de biologie, chimie et géographie, Université du Québec à Rimouski (UQAR), 300 allée des Ursulines, Rimouski (Québec), G5L 3A1, Canada
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Poorter H, Jagodzinski AM, Ruiz‐Peinado R, Kuyah S, Luo Y, Oleksyn J, Usoltsev VA, Buckley TN, Reich PB, Sack L. How does biomass distribution change with size and differ among species? An analysis for 1200 plant species from five continents. THE NEW PHYTOLOGIST 2015; 208:736-749. [PMID: 26197869 PMCID: PMC5034769 DOI: 10.1111/nph.13571] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 06/15/2015] [Indexed: 05/17/2023]
Abstract
We compiled a global database for leaf, stem and root biomass representing c. 11 000 records for c. 1200 herbaceous and woody species grown under either controlled or field conditions. We used this data set to analyse allometric relationships and fractional biomass distribution to leaves, stems and roots. We tested whether allometric scaling exponents are generally constant across plant sizes as predicted by metabolic scaling theory, or whether instead they change dynamically with plant size. We also quantified interspecific variation in biomass distribution among plant families and functional groups. Across all species combined, leaf vs stem and leaf vs root scaling exponents decreased from c. 1.00 for small plants to c. 0.60 for the largest trees considered. Evergreens had substantially higher leaf mass fractions (LMFs) than deciduous species, whereas graminoids maintained higher root mass fractions (RMFs) than eudicotyledonous herbs. These patterns do not support the hypothesis of fixed allometric exponents. Rather, continuous shifts in allometric exponents with plant size during ontogeny and evolution are the norm. Across seed plants, variation in biomass distribution among species is related more to function than phylogeny. We propose that the higher LMF of evergreens at least partly compensates for their relatively low leaf area : leaf mass ratio.
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Affiliation(s)
- Hendrik Poorter
- Plant Sciences (IBG‐2)Forschungszentrum Jülich GmbHD‐52425JülichGermany
| | - Andrzej M. Jagodzinski
- Polish Academy of SciencesInstitute of DendrologyParkowa 5KornikPL‐62‐035Poland
- Department of Game Management and Forest ProtectionFaculty of ForestryPoznan University of Life SciencesWojska Polskiego 71cPoznanPL‐60‐625Poland
| | - Ricardo Ruiz‐Peinado
- Departamento de Selvicultura y Gestión de Sistemas ForestalesINIA‐CIFORAvda. A Coruña, km 7.5.Madrid28040Spain
- Sustainable Forest Management Research InstituteUniversity of Valladolid‐INIAMadridSpain
| | - Shem Kuyah
- Jomo Kenyatta University of Agriculture and Technology (JKUAT)PO Box 62000Nairobi00200Kenya
| | - Yunjian Luo
- Department of EcologySchool of Horticulture and Plant ProtectionYangzhou University48 Wenhui East RoadYangzhou225009China
- State Key Laboratory of Urban and Regional EcologyResearch Centre for Eco‐Environmental SciencesChinese Academy of Sciences18 Shuangqing RoadHaidian DistrictBeijing100085China
| | - Jacek Oleksyn
- Polish Academy of SciencesInstitute of DendrologyParkowa 5KornikPL‐62‐035Poland
- Department of Forest ResourcesUniversity of Minnesota1530 Cleveland Ave NSt PaulMN55108USA
| | - Vladimir A. Usoltsev
- Ural State Forest Engineering UniversitySibirskiy Trakt 37Ekaterinburg620100Russia
- Botanical Garden of Ural Branch of Russian Academy of Sciencesul. Vos'mogo Marta 202aEkaterinburg620144Russia
| | - Thomas N. Buckley
- IA Watson Grains Research CentreFaculty of Agriculture and EnvironmentThe University of Sydney12656 Newell HighwayNarrabriNSWAustralia
| | - Peter B. Reich
- Department of Forest ResourcesUniversity of Minnesota1530 Cleveland Ave NSt PaulMN55108USA
- Hawkesbury Institute for the EnvironmentUniversity of Western SydneyLocked Bag 1797PenrithNSW2751Australia
| | - Lawren Sack
- Department of Ecology and EvolutionUniversity of California Los Angeles621 Charles E. Young Drive SouthLos AngelesCA90095USA
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Sperry JS, Love DM. What plant hydraulics can tell us about responses to climate-change droughts. THE NEW PHYTOLOGIST 2015; 207:14-27. [PMID: 25773898 DOI: 10.1111/nph.13354] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/30/2015] [Indexed: 05/02/2023]
Abstract
Climate change exposes vegetation to unusual drought, causing declines in productivity and increased mortality. Drought responses are hard to anticipate because canopy transpiration and diffusive conductance (G) respond to drying soil and vapor pressure deficit (D) in complex ways. A growing database of hydraulic traits, combined with a parsimonious theory of tree water transport and its regulation, may improve predictions of at-risk vegetation. The theory uses the physics of flow through soil and xylem to quantify how canopy water supply declines with drought and ceases by hydraulic failure. This transpiration 'supply function' is used to predict a water 'loss function' by assuming that stomatal regulation exploits transport capacity while avoiding failure. Supply-loss theory incorporates root distribution, hydraulic redistribution, cavitation vulnerability, and cavitation reversal. The theory efficiently defines stomatal responses to D, drying soil, and hydraulic vulnerability. Driving the theory with climate predicts drought-induced loss of plant hydraulic conductance (k), canopy G, carbon assimilation, and productivity. Data lead to the 'chronic stress hypothesis' wherein > 60% loss of k increases mortality by multiple mechanisms. Supply-loss theory predicts the climatic conditions that push vegetation over this risk threshold. The theory's simplicity and predictive power encourage testing and application in large-scale modeling.
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Affiliation(s)
- John S Sperry
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - David M Love
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
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Anderson‐Teixeira KJ, McGarvey JC, Muller‐Landau HC, Park JY, Gonzalez‐Akre EB, Herrmann V, Bennett AC, So CV, Bourg NA, Thompson JR, McMahon SM, McShea WJ. Size‐related scaling of tree form and function in a mixed‐age forest. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12470] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kristina J. Anderson‐Teixeira
- Center for Tropical Forest Science‐Forest Global Earth Observatory Smithsonian Tropical Research Institute Panama Republic of Panama 9100 Panama City PlWashingtonDC 20521‐9100 USA
- Conservation Ecology Center Smithsonian Conservation Biology Institute National Zoological Park 1500 Remount Rd. Front Royal VA 22630USA
| | - Jennifer C. McGarvey
- Conservation Ecology Center Smithsonian Conservation Biology Institute National Zoological Park 1500 Remount Rd. Front Royal VA 22630USA
| | - Helene C. Muller‐Landau
- Center for Tropical Forest Science‐Forest Global Earth Observatory Smithsonian Tropical Research Institute Panama Republic of Panama 9100 Panama City PlWashingtonDC 20521‐9100 USA
| | - Janice Y. Park
- Conservation Ecology Center Smithsonian Conservation Biology Institute National Zoological Park 1500 Remount Rd. Front Royal VA 22630USA
| | - Erika B. Gonzalez‐Akre
- Conservation Ecology Center Smithsonian Conservation Biology Institute National Zoological Park 1500 Remount Rd. Front Royal VA 22630USA
| | - Valentine Herrmann
- Conservation Ecology Center Smithsonian Conservation Biology Institute National Zoological Park 1500 Remount Rd. Front Royal VA 22630USA
| | - Amy C. Bennett
- Conservation Ecology Center Smithsonian Conservation Biology Institute National Zoological Park 1500 Remount Rd. Front Royal VA 22630USA
| | - Christopher V. So
- Conservation Ecology Center Smithsonian Conservation Biology Institute National Zoological Park 1500 Remount Rd. Front Royal VA 22630USA
| | - Norman A. Bourg
- Conservation Ecology Center Smithsonian Conservation Biology Institute National Zoological Park 1500 Remount Rd. Front Royal VA 22630USA
| | | | - Sean M. McMahon
- Center for Tropical Forest Science‐Forest Global Earth Observatory Smithsonian Tropical Research Institute Panama Republic of Panama 9100 Panama City PlWashingtonDC 20521‐9100 USA
- Forest Ecology Group Smithsonian Environmental Research Center PO Box 28 Edgewater MD 21037USA
| | - William J. McShea
- Conservation Ecology Center Smithsonian Conservation Biology Institute National Zoological Park 1500 Remount Rd. Front Royal VA 22630USA
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Smith DD, Sperry JS. Coordination between water transport capacity, biomass growth, metabolic scaling and species stature in co-occurring shrub and tree species. PLANT, CELL & ENVIRONMENT 2014; 37:2679-90. [PMID: 25041417 DOI: 10.1111/pce.12408] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/03/2014] [Accepted: 07/07/2014] [Indexed: 05/13/2023]
Abstract
The significance of xylem function and metabolic scaling theory begins from the idea that water transport is strongly coupled to growth rate. At the same time, coordination of water transport and growth seemingly should differ between plant functional types. We evaluated the relationships between water transport, growth and species stature in six species of co-occurring trees and shrubs. Within species, a strong proportionality between plant hydraulic conductance (K), sap flow (Q) and shoot biomass growth (G) was generally supported. Across species, however, trees grew more for a given K or Q than shrubs, indicating greater growth-based water-use efficiency (WUE) in trees. Trees also showed slower decline in relative growth rate (RGR) than shrubs, equivalent to a steeper G by mass (M) scaling exponent in trees (0.77-0.98). The K and Q by M scaling exponents were common across all species (0.80, 0.82), suggesting that the steeper G scaling in trees reflects a size-dependent increase in their growth-based WUE. The common K and Q by M exponents were statistically consistent with the 0.75 of ideal scaling theory. A model based upon xylem anatomy and branching architecture consistently predicted the observed K by M scaling exponents but only when deviations from ideal symmetric branching were incorporated.
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Affiliation(s)
- Duncan D Smith
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
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