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Quattrone A, Lopez-Guerrero M, Yadav P, Meier MA, Russo SE, Weber KA. Interactions between root hairs and the soil microbial community affect the growth of maize seedlings. PLANT, CELL & ENVIRONMENT 2024; 47:611-628. [PMID: 37974552 DOI: 10.1111/pce.14755] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 09/01/2023] [Accepted: 10/18/2023] [Indexed: 11/19/2023]
Abstract
Root hairs are considered important for rhizosphere formation, which affects root system functioning. Through interactions with soil microorganisms mediated by root exudation, root hairs may affect the phenotypes and growth of young plants. We tested this hypothesis by integrating results from two experiments: (1) a factorial greenhouse seedling experiment with Zea mays B73-wt and its root-hairless mutant, B73-rth3, grown in live and autoclaved soil, quantifying 15 phenotypic traits, seven growth rates, and soil microbiomes and (2) a semi-hydroponic system quantifying root exudation of maize genotypes. Possibly as compensation for lacking root hairs, B73-rth3 seedlings allocated more biomass to roots and grew slower than B73-wt seedlings in live soil, whereas B73-wt seedlings grew slowest in autoclaved soil, suggesting root hairs can be costly and their benefits were realized with more complete soil microbial assemblages. There were substantial differences in root exudation between genotypes and in rhizosphere versus non-rhizosphere microbiomes. The microbial taxa enriched in the presence of root hairs generally enhanced growth compared to taxa enriched in their absence. Our findings suggest the root hairs' adaptive value extends to plant-microbe interactions mediated by root exudates, affecting plant phenotypes, and ultimately, growth.
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Affiliation(s)
- Amanda Quattrone
- Complex Biosystems Ph.D. program, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | | | - Pooja Yadav
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Michael A Meier
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
- Rancho Biosciences, San Diego, California, USA
| | - Sabrina E Russo
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Karrie A Weber
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
- Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
- Daugherty Water for Food Institute, University of Nebraska, Lincoln, Nebraska, USA
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Russo SE, Ledder G, Muller EB, Nisbet RM. Dynamic Energy Budget models: fertile ground for understanding resource allocation in plants in a changing world. CONSERVATION PHYSIOLOGY 2022; 10:coac061. [PMID: 36128259 PMCID: PMC9477497 DOI: 10.1093/conphys/coac061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/08/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
Climate change is having dramatic effects on the diversity and distribution of species. Many of these effects are mediated by how an organism's physiological patterns of resource allocation translate into fitness through effects on growth, survival and reproduction. Empirically, resource allocation is challenging to measure directly and so has often been approached using mathematical models, such as Dynamic Energy Budget (DEB) models. The fact that all plants require a very similar set of exogenous resources, namely light, water and nutrients, integrates well with the DEB framework in which a small number of variables and processes linked through pathways represent an organism's state as it changes through time. Most DEB theory has been developed in reference to animals and microorganisms. However, terrestrial vascular plants differ from these organisms in fundamental ways that make resource allocation, and the trade-offs and feedbacks arising from it, particularly fundamental to their life histories, but also challenging to represent using existing DEB theory. Here, we describe key features of the anatomy, morphology, physiology, biochemistry, and ecology of terrestrial vascular plants that should be considered in the development of a generic DEB model for plants. We then describe possible approaches to doing so using existing DEB theory and point out features that may require significant development for DEB theory to accommodate them. We end by presenting a generic DEB model for plants that accounts for many of these key features and describing gaps that would need to be addressed for DEB theory to predict the responses of plants to climate change. DEB models offer a powerful and generalizable framework for modelling resource allocation in terrestrial vascular plants, and our review contributes a framework for expansion and development of DEB theory to address how plants respond to anthropogenic change.
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Affiliation(s)
- Sabrina E Russo
- School of Biological Sciences, University of Nebraska, 1104 T Street Lincoln, Nebraska 68588-0118, USA
- Center for Plant Science Innovation, University of Nebraska, 1901 Vine Street, N300 Beadle Center, Lincoln, Nebraska 68588-0660, USA
| | - Glenn Ledder
- Department of Mathematics, University of Nebraska, 203 Avery Hall, Lincoln, Nebraska 68588-0130, USA
| | - Erik B Muller
- Marine Science Institute, University of California, Santa Barbara, California 93106, USA
- Institut für Biologische Analytik und Consulting IBACON GmbH, Arheilger Weg 17 Roß dorf, Hesse D-64380, Germany
| | - Roger M Nisbet
- Marine Science Institute, University of California, Santa Barbara, California 93106, USA
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California 93106, USA
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Yin X, Hao G, Sterck F. A trade‐off between growth and hydraulic resilience against freezing leads to divergent adaptations among temperate tree species. Funct Ecol 2022. [DOI: 10.1111/1365-2435.13991] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiao‐Han Yin
- CAS Key Laboratory of Forest Ecology and Management & Key Laboratory of Terrestrial Ecosystem Carbon Neutrality, Liaoning Province Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
- Forest Ecology and Forest Management Group Wageningen University Wageningen The Netherlands
| | - Guang‐You Hao
- CAS Key Laboratory of Forest Ecology and Management & Key Laboratory of Terrestrial Ecosystem Carbon Neutrality, Liaoning Province Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
| | - Frank Sterck
- Forest Ecology and Forest Management Group Wageningen University Wageningen The Netherlands
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O’Sullivan H, Raumonen P, Kaitaniemi P, Perttunen J, Sievänen R. Integrating terrestrial laser scanning with functional-structural plant models to investigate ecological and evolutionary processes of forest communities. ANNALS OF BOTANY 2021; 128:663-684. [PMID: 34610091 PMCID: PMC8557364 DOI: 10.1093/aob/mcab120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 09/13/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Woody plants (trees and shrubs) play an important role in terrestrial ecosystems, but their size and longevity make them difficult subjects for traditional experiments. In the last 20 years functional-structural plant models (FSPMs) have evolved: they consider the interplay between plant modular structure, the immediate environment and internal functioning. However, computational constraints and data deficiency have long been limiting factors in a broader application of FSPMs, particularly at the scale of forest communities. Recently, terrestrial laser scanning (TLS), has emerged as an invaluable tool for capturing the 3-D structure of forest communities, thus opening up exciting opportunities to explore and predict forest dynamics with FSPMs. SCOPE The potential synergies between TLS-derived data and FSPMs have yet to be fully explored. Here, we summarize recent developments in FSPM and TLS research, with a specific focus on woody plants. We then evaluate the emerging opportunities for applying FSPMs in an ecological and evolutionary context, in light of TLS-derived data, with particular consideration of the challenges posed by scaling up from individual trees to whole forests. Finally, we propose guidelines for incorporating TLS data into the FSPM workflow to encourage overlap of practice amongst researchers. CONCLUSIONS We conclude that TLS is a feasible tool to help shift FSPMs from an individual-level modelling technique to a community-level one. The ability to scan multiple trees, of multiple species, in a short amount of time, is paramount to gathering the detailed structural information required for parameterizing FSPMs for forest communities. Conventional techniques, such as repeated manual forest surveys, have their limitations in explaining the driving mechanisms behind observed patterns in 3-D forest structure and dynamics. Therefore, other techniques are valuable to explore how forests might respond to environmental change. A robust synthesis between TLS and FSPMs provides the opportunity to virtually explore the spatial and temporal dynamics of forest communities.
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Affiliation(s)
- Hannah O’Sullivan
- Department of Life Sciences, Imperial College London, Silwood Park, Ascot, Berkshire, SL5 7PY, UK
- Royal Botanic Gardens, Kew, Richmond, UK
| | - Pasi Raumonen
- Mathematics, Tampere University, Korkeakoulunkatu 7, FI-33720 Tampere, Finland
| | - Pekka Kaitaniemi
- Hyytiälä Forestry Field Station, Faculty of Agriculture and Forestry, University of Helsinki, Hyytiäläntie 124, FI-35500 Korkeakoski, Finland
| | - Jari Perttunen
- Natural Resources Institute Finland, Latokartanontie 9, 00790 Helsinki, Finland
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Jespersen E, Kirk GH, Brix H, Eller F, Sorrell BK. Shade and salinity responses of two dominant coastal wetland grasses: implications for light competition at the transition zone. ANNALS OF BOTANY 2021; 128:469-480. [PMID: 34259823 PMCID: PMC8414928 DOI: 10.1093/aob/mcab089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Coastal wetlands are threatened by the increased salinity that may result from sea level rise. Salinity stress alters species zonation patterns through changes in competitive outcome between species differing in salinity tolerance. This study therefore aimed to understand how salinity and light affect two dominant and competing coastal wetland grasses that differ in salt tolerance, height and photosynthetic metabolism. METHODS The C4 species Spartina anglica and the C3 species Phragmites australis were grown at five salinity levels (0, 7, 14, 21 and 28 ppt) and two light fluxes (100 % and 50 % of natural daylight) in an outdoor experimental setup for 102 d with full access to nutrients. KEY RESULTS Salinity reduced the biomass, height and shoot density of P. australis from 81.7 g dry weight (DW), 0.73 m and 37 shoots per pot at a salinity of 0 ppt to 16.8 gDW, 0.3 m and 14 shoots per pot at a salinity of 28 ppt. Biomass, height and shoot density of S. anglica did not respond or were only slightly reduced at the highest salinity of 28 ppt. High salinity also resulted in a higher tissue concentration of N and P in P. australis. Both species had low ability to acclimate to the lower light flux. Shade acclimation in S. anglica occurred via modest changes in specific leaf area, pigment content and biomass allocation. CONCLUSIONS High salinity reduced traits important for light competition and increased the nutrient concentration in P. australis leaf and root biomass, while this was overall unaffected in S. anglica. This is likely to reduce the competitive ability of P. australis over S. anglica for light because at high salinities the former cannot effectively shade the lower-growing S. anglica. Neither species effectively acclimates to shade, which could explain why S. anglica does not occur in the understorey of P. australis at low salinities.
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Affiliation(s)
- Emil Jespersen
- Department of Biology, Aarhus University, Ole Worms Alle 1, 8000 Aarhus C., Denmark
| | - Gro H Kirk
- Department of Biology, Aarhus University, Ole Worms Alle 1, 8000 Aarhus C., Denmark
| | - Hans Brix
- Department of Biology, Aarhus University, Ole Worms Alle 1, 8000 Aarhus C., Denmark
| | - Franziska Eller
- Department of Biology, Aarhus University, Ole Worms Alle 1, 8000 Aarhus C., Denmark
| | - Brian K Sorrell
- Department of Biology, Aarhus University, Ole Worms Alle 1, 8000 Aarhus C., Denmark
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Bartholomew DC, Bittencourt PRL, da Costa ACL, Banin LF, de Britto Costa P, Coughlin SI, Domingues TF, Ferreira LV, Giles A, Mencuccini M, Mercado L, Miatto RC, Oliveira A, Oliveira R, Meir P, Rowland L. Small tropical forest trees have a greater capacity to adjust carbon metabolism to long-term drought than large canopy trees. PLANT, CELL & ENVIRONMENT 2020; 43:2380-2393. [PMID: 32643169 DOI: 10.1111/pce.13838] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
The response of small understory trees to long-term drought is vital in determining the future composition, carbon stocks and dynamics of tropical forests. Long-term drought is, however, also likely to expose understory trees to increased light availability driven by drought-induced mortality. Relatively little is known about the potential for understory trees to adjust their physiology to both decreasing water and increasing light availability. We analysed data on maximum photosynthetic capacity (Jmax , Vcmax ), leaf respiration (Rleaf ), leaf mass per area (LMA), leaf thickness and leaf nitrogen and phosphorus concentrations from 66 small trees across 12 common genera at the world's longest running tropical rainfall exclusion experiment and compared responses to those from 61 surviving canopy trees. Small trees increased Jmax , Vcmax , Rleaf and LMA (71, 29, 32, 15% respectively) in response to the drought treatment, but leaf thickness and leaf nutrient concentrations did not change. Small trees were significantly more responsive than large canopy trees to the drought treatment, suggesting greater phenotypic plasticity and resilience to prolonged drought, although differences among taxa were observed. Our results highlight that small tropical trees have greater capacity to respond to ecosystem level changes and have the potential to regenerate resilient forests following future droughts.
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Affiliation(s)
- David C Bartholomew
- School of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Paulo R L Bittencourt
- School of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | | | | | | | - Sarah I Coughlin
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Tomas F Domingues
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - André Giles
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | - Maurizio Mencuccini
- ICREA, Barcelona, Spain
- CREAF, Universidad Autonoma de Barcelona, Barcelona, Spain
| | - Lina Mercado
- School of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- UK Centre for Ecology and Hydrology, Wallingford, UK
| | - Raquel C Miatto
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - Rafael Oliveira
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | - Patrick Meir
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | - Lucy Rowland
- School of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
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Ledder G, Russo SE, Muller EB, Peace A, Nisbet RM. Local control of resource allocation is sufficient to model optimal dynamics in syntrophic systems. THEOR ECOL-NETH 2020. [DOI: 10.1007/s12080-020-00464-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Weemstra M, Kiorapostolou N, Ruijven J, Mommer L, Vries J, Sterck F. The role of fine‐root mass, specific root length and life span in tree performance: A whole‐tree exploration. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13520] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Monique Weemstra
- Forest Ecology and Forest Management Group Wageningen University Wageningen the Netherlands
- Plant Ecology and Nature Conservation Group Wageningen University Wageningen the Netherlands
| | - Natasa Kiorapostolou
- Forest Ecology and Forest Management Group Wageningen University Wageningen the Netherlands
- Department Territorio e Sistemi Agro‐Forestali University of Padova Legnaro Italy
| | - Jasper Ruijven
- Plant Ecology and Nature Conservation Group Wageningen University Wageningen the Netherlands
| | - Liesje Mommer
- Plant Ecology and Nature Conservation Group Wageningen University Wageningen the Netherlands
| | - Jorad Vries
- Centre for Crop System Analysis Wageningen University Wageningen the Netherlands
| | - Frank Sterck
- Forest Ecology and Forest Management Group Wageningen University Wageningen the Netherlands
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Zakharova L, Meyer K, Seifan M. Trait-based modelling in ecology: A review of two decades of research. Ecol Modell 2019. [DOI: 10.1016/j.ecolmodel.2019.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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10
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Effects of Forest Canopy Vertical Stratification on the Estimation of Gross Primary Production by Remote Sensing. REMOTE SENSING 2018. [DOI: 10.3390/rs10091329] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Gross primary production (GPP) in forests is the most important carbon flux in terrestrial ecosystems. Forest ecosystems with high leaf area index (LAI) values have diverse species or complex forest structures with vertical stratifications that influence the carbon–water–energy cycles. In this study, we used three light use efficiency (LUE) GPP models and site-level experiment data to analyze the effects of the vertical stratification of dense forest vegetation on the estimates of remotely sensed GPP during the growing season of two forest sites in East Asia: Dinghushan (DHS) and Tomakomai (TMK). The results showed that different controlling environmental factors of the vertical layers, such as temperature and vapor pressure deficit (VPD), produce different responses for the same LUE value in the different sub-ecosystems (defined as the tree, shrub, and grass layers), which influences the GPP estimation. Air temperature and VPD play important roles in the effects of vertical stratification on the GPP estimates in dense forests, which led to differences in GPP uncertainties from −50% to 30% because of the distinct temperature responses in TMK. The unequal vertical LAI distributions in the different sub-ecosystems led to GPP variations of 1–2 gC/m2/day with uncertainties of approximately −30% to 20% because sub-ecosystems have unique absorbed fractions of photosynthetically active radiation (APAR) and LUE. A comparison with the flux tower-based GPP data indicated that the GPP estimations from the LUE and APAR values from separate vertical layers exhibited better model performance than those calculated using the single-layer method, with 10% less bias in DHS and more than 70% less bias in TMK. The precision of the estimated GPP in regions with thick understory vegetation could be effectively improved by considering the vertical variations in environmental parameters and the LAI values of different sub-ecosystems as separate factors when calculating the GPP of different components. Our results provide useful insight that can be used to improve the accuracy of remote sensing GPP estimations by considering vertical stratification parameters along with the LAI of sub-ecosystems in dense forests.
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Gleason SM, Stephens AEA, Tozer WC, Blackman CJ, Butler DW, Chang Y, Cook AM, Cooke J, Laws CA, Rosell JA, Stuart SA, Westoby M. Shoot growth of woody trees and shrubs is predicted by maximum plant height and associated traits. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12972] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sean M. Gleason
- Department of Biological Sciences Macquarie University Sydney NSW Australia
- USDA‐ARS Water Management and Systems Research Unit Fort Collins CO USA
| | - Andrea E. A. Stephens
- Department of Biological Sciences Macquarie University Sydney NSW Australia
- Department of Zoology University of Oxford Oxford UK
| | - Wade C. Tozer
- Department of Biological Sciences Macquarie University Sydney NSW Australia
| | - Chris J. Blackman
- Department of Biological Sciences Macquarie University Sydney NSW Australia
- Hawkesbury Institute for the Environment Western Sydney University Richmond NSW Australia
| | - Don W. Butler
- Department of Biological Sciences Macquarie University Sydney NSW Australia
- Queensland Herbarium Toowong Qld Australia
| | - Yvonne Chang
- Department of Biological Sciences Macquarie University Sydney NSW Australia
- CSIRO Agriculture Narrabri NSW Australia
| | - Alicia M. Cook
- Department of Biological Sciences Macquarie University Sydney NSW Australia
- School of Life Science University of Technology Sydney Ultimo NSW Australia
| | - Julia Cooke
- Department of Biological Sciences Macquarie University Sydney NSW Australia
- School of Environment, Earth and Ecosystem Sciences The Open University Milton Keynes, Buckinghamshire UK
| | - Claire A. Laws
- Department of Biological Sciences Macquarie University Sydney NSW Australia
| | - Julieta A. Rosell
- Department of Biological Sciences Macquarie University Sydney NSW Australia
- Departamento de Ecología de la Biodiversidad Instituto de Ecología Universidad Nacional Autónoma de México Mexico DF Mexico
| | - Stephanie A. Stuart
- Department of Biological Sciences Macquarie University Sydney NSW Australia
- Hawkesbury Institute for the Environment Western Sydney University Richmond NSW Australia
| | - Mark Westoby
- Department of Biological Sciences Macquarie University Sydney NSW Australia
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Montes-Pulido CR, Parrado-Rosselli Á, Álvarez-Dávila E. Tipos funcionales de plantas como estimadores de carbono en bosque seco del Caribe colombiano. REV MEX BIODIVERS 2017. [DOI: 10.1016/j.rmb.2017.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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13
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van Loon MP, Rietkerk M, Dekker SC, Hikosaka K, Ueda MU, Anten NPR. Plant-plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas. ANNALS OF BOTANY 2016; 117:1197-207. [PMID: 27192707 PMCID: PMC4904180 DOI: 10.1093/aob/mcw064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 01/01/2016] [Accepted: 02/26/2016] [Indexed: 05/12/2023]
Abstract
BACKGROUND AND AIMS The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant-plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may benefit more from [CO2] elevation than others. The relative contribution of plastic (within the plant's lifetime) and genotypic (over several generations) responses to elevated [CO2] on plant performance was investigated and how these patterns are modified by plant-plant interactions was analysed. METHODS Plantago asiatica seeds originating from natural CO2 springs and from ambient [CO2] sites were grown in mono stands of each one of the two origins as well as mixtures of both origins. In total, 1944 plants were grown in [CO2]-controlled walk-in climate rooms, under a [CO2] of 270, 450 and 750 ppm. A model was used for upscaling from leaf to whole-plant photosynthesis and for quantifying the influence of plastic and genotypic responses. KEY RESULTS It was shown that changes in canopy photosynthesis, specific leaf area (SLA) and stomatal conductance in response to changes in growth [CO2] were mainly determined by plastic and not by genotypic responses. We further found that plants originating from high [CO2] habitats performed better in terms of whole-plant photosynthesis, biomass and leaf area, than those from ambient [CO2] habitats at elevated [CO2] only when both genotypes competed. Similarly, plants from ambient [CO2] habitats performed better at low [CO2], also only when both genotypes competed. No difference in performance was found in mono stands. CONCLUSION The results indicate that natural selection under increasing [CO2] will be mainly driven by competitive interactions. This supports the notion that plant-plant interactions have an important influence on future vegetation functioning and species distribution. Furthermore, plant performance was mainly driven by plastic and not by genotypic responses to changes in atmospheric [CO2].
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Affiliation(s)
- Marloes P van Loon
- Ecology and Biodiversity Group, Utrecht University, 3508 TB, Utrecht, The Netherlands Centre for Crop Systems Analysis, Wageningen University, 6700 AK, Wageningen, The Netherlands
| | - Max Rietkerk
- Department of Environmental Sciences, Copernicus Institute for Sustainable development, Utrecht University, 3508 TC, Utrecht, The Netherlands
| | - Stefan C Dekker
- Department of Environmental Sciences, Copernicus Institute for Sustainable development, Utrecht University, 3508 TC, Utrecht, The Netherlands
| | - Kouki Hikosaka
- Graduate School of Life Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan
| | - Miki U Ueda
- Graduate School of Life Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan
| | - Niels P R Anten
- Centre for Crop Systems Analysis, Wageningen University, 6700 AK, Wageningen, The Netherlands
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Sterck F, Anten NPR, Schieving F, Zuidema PA. Trait Acclimation Mitigates Mortality Risks of Tropical Canopy Trees under Global Warming. FRONTIERS IN PLANT SCIENCE 2016; 7:607. [PMID: 27242814 PMCID: PMC4863428 DOI: 10.3389/fpls.2016.00607] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/20/2016] [Indexed: 05/24/2023]
Abstract
There is a heated debate about the effect of global change on tropical forests. Many scientists predict large-scale tree mortality while others point to mitigating roles of CO2 fertilization and - the notoriously unknown - physiological trait acclimation of trees. In this opinion article we provided a first quantification of the potential of trait acclimation to mitigate the negative effects of warming on tropical canopy tree growth and survival. We applied a physiological tree growth model that incorporates trait acclimation through an optimization approach. Our model estimated the maximum effect of acclimation when trees optimize traits that are strongly plastic on a week to annual time scale (leaf photosynthetic capacity, total leaf area, stem sapwood area) to maximize carbon gain. We simulated tree carbon gain for temperatures (25-35°C) and ambient CO2 concentrations (390-800 ppm) predicted for the 21st century. Full trait acclimation increased simulated carbon gain by up to 10-20% and the maximum tolerated temperature by up to 2°C, thus reducing risks of tree death under predicted warming. Functional trait acclimation may thus increase the resilience of tropical trees to warming, but cannot prevent tree death during extremely hot and dry years at current CO2 levels. We call for incorporating trait acclimation in field and experimental studies of plant functional traits, and in models that predict responses of tropical forests to climate change.
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Affiliation(s)
- Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen UniversityWageningen, Netherlands
| | - Niels P. R. Anten
- Centre for Crop Systems Analysis, Wageningen UniversityWageningen, Netherlands
- Ecology and Biodiversity Group, Department of Biology, Utrecht UniversityUtrecht, Netherlands
| | - Feike Schieving
- Ecology and Biodiversity Group, Department of Biology, Utrecht UniversityUtrecht, Netherlands
| | - Pieter A. Zuidema
- Forest Ecology and Forest Management Group, Wageningen UniversityWageningen, Netherlands
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15
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Gleason SM, Blackman CJ, Chang Y, Cook AM, Laws CA, Westoby M. Weak coordination among petiole, leaf, vein, and gas-exchange traits across Australian angiosperm species and its possible implications. Ecol Evol 2015; 6:267-78. [PMID: 26811791 PMCID: PMC4716519 DOI: 10.1002/ece3.1860] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 10/22/2015] [Accepted: 10/23/2015] [Indexed: 11/30/2022] Open
Abstract
Close coordination between leaf gas exchange and maximal hydraulic supply has been reported across diverse plant life forms. However, it has also been suggested that this relationship may become weak or break down completely within the angiosperms. We examined coordination between hydraulic, leaf vein, and gas‐exchange traits across a diverse group of 35 evergreen Australian angiosperms, spanning a large range in leaf structure and habitat. Leaf‐specific conductance was calculated from petiole vessel anatomy and was also measured directly using the rehydration technique. Leaf vein density (thought to be a determinant of gas exchange rate), maximal stomatal conductance, and net CO2 assimilation rate were also measured for most species (n = 19–35). Vein density was not correlated with leaf‐specific conductance (either calculated or measured), stomatal conductance, nor maximal net CO2 assimilation, with r2 values ranging from 0.00 to 0.11, P values from 0.909 to 0.102, and n values from 19 to 35 in all cases. Leaf‐specific conductance calculated from petiole anatomy was weakly correlated with maximal stomatal conductance (r2 = 0.16; P = 0.022; n = 32), whereas the direct measurement of leaf‐specific conductance was weakly correlated with net maximal CO2 assimilation (r2 = 0.21; P = 0.005; n = 35). Calculated leaf‐specific conductance, xylem ultrastructure, and leaf vein density do not appear to be reliable proxy traits for assessing differences in rates of gas exchange or growth across diverse sets of evergreen angiosperms.
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Affiliation(s)
- Sean M Gleason
- Department of Biological Sciences Macquarie University North Ryde NSW 2109 Australia; Water Management Research Unit USDA-ARS Fort Collins Colorado 80526
| | - Chris J Blackman
- Department of Biological Sciences Macquarie University North Ryde NSW 2109 Australia; Hawkesbury Institute for the Environment University of Western Sydney Richmond NSW 2753 Australia
| | - Yvonne Chang
- Department of Biological Sciences Macquarie University North Ryde NSW 2109 Australia; CSIRO Agriculture LB 59 Narrabri NSW 2390 Australia
| | - Alicia M Cook
- Department of Biological Sciences Macquarie University North Ryde NSW 2109 Australia
| | - Claire A Laws
- Department of Biological Sciences Macquarie University North Ryde NSW 2109 Australia
| | - Mark Westoby
- Department of Biological Sciences Macquarie University North Ryde NSW 2109 Australia
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Schippers P, Sterck F, Vlam M, Zuidema PA. Tree growth variation in the tropical forest: understanding effects of temperature, rainfall and CO 2. GLOBAL CHANGE BIOLOGY 2015; 21:2749-2761. [PMID: 25626673 DOI: 10.1111/gcb.12877] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 12/14/2014] [Indexed: 05/06/2023]
Abstract
Tropical forest responses to climatic variability have important consequences for global carbon cycling, but are poorly understood. As empirical, correlative studies cannot disentangle the interactive effects of climatic variables on tree growth, we used a tree growth model (IBTREE) to unravel the climate effects on different physiological pathways and in turn on stem growth variation. We parameterized the model for canopy trees of Toona ciliata (Meliaceae) from a Thai monsoon forest and compared predicted and measured variation from a tree-ring study over a 30-year period. We used historical climatic variation of minimum and maximum day temperature, precipitation and carbon dioxide (CO2 ) in different combinations to estimate the contribution of each climate factor in explaining the inter-annual variation in stem growth. Running the model with only variation in maximum temperature and rainfall yielded stem growth patterns that explained almost 70% of the observed inter-annual variation in stem growth. Our results show that maximum temperature had a strong negative effect on the stem growth by increasing respiration, reducing stomatal conductance and thus mitigating a higher transpiration demand, and - to a lesser extent - by directly reducing photosynthesis. Although stem growth was rather weakly sensitive to rain, stem growth variation responded strongly and positively to rainfall variation owing to the strong inter-annual fluctuations in rainfall. Minimum temperature and atmospheric CO2 concentration did not significantly contribute to explaining the inter-annual variation in stem growth. Our innovative approach - combining a simulation model with historical data on tree-ring growth and climate - allowed disentangling the effects of strongly correlated climate variables on growth through different physiological pathways. Similar studies on different species and in different forest types are needed to further improve our understanding of the sensitivity of tropical tree growth to climatic variability and change.
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Affiliation(s)
- Peter Schippers
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA, Wageningen, The Netherlands
- Team Biodiversity and Policy, ALTERRA, Wageningen University and Research Centre, PO Box 47, 6700 AA, Wageningen, The Netherlands
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA, Wageningen, The Netherlands
| | - Mart Vlam
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA, Wageningen, The Netherlands
| | - Pieter A Zuidema
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA, Wageningen, The Netherlands
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17
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Schippers P, Vlam M, Zuidema PA, Sterck F. Sapwood allocation in tropical trees: a test of hypotheses. FUNCTIONAL PLANT BIOLOGY : FPB 2015; 42:697-709. [PMID: 32480713 DOI: 10.1071/fp14127] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 04/13/2015] [Indexed: 06/11/2023]
Abstract
Carbon allocation to sapwood in tropical canopy trees is a key process determining forest carbon sequestration, and is at the heart of tree growth and dynamic global vegetation models (DGVM). Several allocation hypotheses exist including those applying assumptions on fixed allocation, pipe model, and hierarchical allocation between plant organs. We use a tree growth model (IBTREE) to evaluate these hypotheses by comparing simulated sapwood growth with 30 year tree ring records of the tropical long-lived tree Toona ciliata M. Roem. in Thailand. Simulated annual variation in wood production varied among hypotheses. Observed and simulated growth patterns matched most closely (r2=0.70) when hierarchical allocation was implemented, with low priority for sapwood. This allocation method showed realistic results with respect to reserve dynamics, partitioning and productivity and was the only one able to capture the large annual variation in tree ring width. Consequently, this method might also explain the large temporal variation in diameter growth and the occurrence of missing rings often encountered in other tropical tree species. Overall, our results show that sapwood growth is highly sensitive to allocation principles, and that allocation assumptions may greatly influence estimated carbon sequestration of tropical forests under climatic change.
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Affiliation(s)
- Peter Schippers
- Forest Ecology and Forest Management Group, Environmental Science Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands
| | - Mart Vlam
- Forest Ecology and Forest Management Group, Environmental Science Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands
| | - Pieter A Zuidema
- Forest Ecology and Forest Management Group, Environmental Science Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Environmental Science Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands
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18
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Amissah L, Mohren GMJ, Kyereh B, Poorter L. The effects of drought and shade on the performance, morphology and physiology of Ghanaian tree species. PLoS One 2015; 10:e0121004. [PMID: 25836337 PMCID: PMC4383566 DOI: 10.1371/journal.pone.0121004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 02/09/2015] [Indexed: 11/24/2022] Open
Abstract
In tropical forests light and water availability are the most important factors for seedling growth and survival but an increasing frequency of drought may affect tree regeneration. One central question is whether drought and shade have interactive effects on seedling growth and survival. Here, we present results of a greenhouse experiment, in which seedlings of 10 Ghanaian tree species were exposed to combinations of strong seasonal drought (continuous watering versus withholding water for nine weeks) and shade (5% irradiance versus 20% irradiance). We evaluated the effects of drought and shade on seedling survival and growth and plasticity of 11 underlying traits related to biomass allocation, morphology and physiology. Seedling survival under dry conditions was higher in shade than in high light, thus providing support for the "facilitation hypothesis" that shade enhances plant performance through improved microclimatic conditions, and rejecting the trade-off hypothesis that drought should have stronger impact in shade because of reduced root investment. Shaded plants had low biomass fraction in roots, in line with the trade-off hypothesis, but they compensated for this with a higher specific root length (i.e., root length per unit root mass), resulting in a similar root length per plant mass and, hence, similar water uptake capacity as high-light plants. The majority (60%) of traits studied responded independently to drought and shade, indicating that within species shade- and drought tolerances are not in trade-off, but largely uncoupled. When individual species responses were analysed, then for most of the traits only one to three species showed significant interactive effects between drought and shade. The uncoupled response of most species to drought and shade should provide ample opportunity for niche differentiation and species coexistence under a range of water and light conditions. Overall our greenhouse results suggest that, in the absence of root competition shaded tropical forest tree seedlings may be able to survive prolonged drought.
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Affiliation(s)
- Lucy Amissah
- Council for Scientific and Industrial Research—Forestry Research Institute of Ghana, KNUST, Kumasi, Ghana
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, The Netherlands
| | - Godefridus M. J. Mohren
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, The Netherlands
| | - Boateng Kyereh
- College of Agriculture and Natural Resources, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Lourens Poorter
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, The Netherlands
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19
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van der Sande MT, Zuidema PA, Sterck F. Explaining biomass growth of tropical canopy trees: the importance of sapwood. Oecologia 2015; 177:1145-55. [PMID: 25634307 PMCID: PMC4363484 DOI: 10.1007/s00442-015-3220-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 01/03/2015] [Indexed: 12/02/2022]
Abstract
Tropical forests are important in worldwide carbon (C) storage and sequestration. C sequestration of these forests may especially be determined by the growth of canopy trees. However, the factors driving variation in growth among such large individuals remain largely unclear. We evaluate how crown traits [total leaf area, specific leaf area and leaf nitrogen (N) concentration] and stem traits [sapwood area (SA) and sapwood N concentration] measured for individual trees affect absolute biomass growth for 43 tropical canopy trees belonging to four species, in a moist forest in Bolivia. Biomass growth varied strongly among trees, between 17.3 and 367.3 kg year−1, with an average of 105.4 kg year−1. We found that variation in biomass growth was chiefly explained by a positive effect of SA, and not by tree size or other traits examined. SA itself was positively associated with sapwood growth, sapwood lifespan and basal area. We speculate that SA positively affects the growth of individual trees mainly by increasing water storage, thus securing water supply to the crown. These positive roles of sapwood on growth apparently offset the increased respiration costs incurred by more sapwood. This is one of the first individual-based studies to show that variation in sapwood traits—and not crown traits—explains variation in growth among tropical canopy trees. Accurate predictions of C dynamics in tropical forests require similar studies on biomass growth of individual trees as well as studies evaluating the dual effect of sapwood (water provision vs. respiratory costs) on tropical tree growth.
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Affiliation(s)
- Masha T van der Sande
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA, Wageningen, The Netherlands,
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20
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van Loon MP, Schieving F, Rietkerk M, Dekker SC, Sterck F, Anten NPR. How light competition between plants affects their response to climate change. THE NEW PHYTOLOGIST 2014; 203:1253-1265. [PMID: 24890127 DOI: 10.1111/nph.12865] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 04/26/2014] [Indexed: 05/10/2023]
Abstract
How plants respond to climate change is of major concern, as plants will strongly impact future ecosystem functioning, food production and climate. Here, we investigated how vegetation structure and functioning may be influenced by predicted increases in annual temperatures and atmospheric CO2 concentration, and modeled the extent to which local plant-plant interactions may modify these effects. A canopy model was developed, which calculates photosynthesis as a function of light, nitrogen, temperature, CO2 and water availability, and considers different degrees of light competition between neighboring plants through canopy mixing; soybean (Glycine max) was used as a reference system. The model predicts increased net photosynthesis and reduced stomatal conductance and transpiration under atmospheric CO2 increase. When CO2 elevation is combined with warming, photosynthesis is increased more, but transpiration is reduced less. Intriguingly, when competition is considered, the optimal response shifts to producing larger leaf areas, but with lower stomatal conductance and associated vegetation transpiration than when competition is not considered. Furthermore, only when competition is considered are the predicted effects of elevated CO2 on leaf area index (LAI) well within the range of observed effects obtained by Free air CO2 enrichment (FACE) experiments. Together, our results illustrate how competition between plants may modify vegetation responses to climate change.
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Affiliation(s)
- Marloes P van Loon
- Ecology and Biodiversity Group, Utrecht University, Postbox 80084, 3508 TB, Utrecht, the Netherlands
- Centre for Crop Systems Analysis, Wageningen University, Postbox 430, 6700 AK, Wageningen, the Netherlands
| | - Feike Schieving
- Ecology and Biodiversity Group, Utrecht University, Postbox 80084, 3508 TB, Utrecht, the Netherlands
| | - Max Rietkerk
- Department of Environmental Sciences, Copernicus Institute for Sustainable Development, Utrecht University, Postbox 80115, 3508 TC, Utrecht, the Netherlands
| | - Stefan C Dekker
- Department of Environmental Sciences, Copernicus Institute for Sustainable Development, Utrecht University, Postbox 80115, 3508 TC, Utrecht, the Netherlands
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University, Postbox 47, 6700 AA, Wageningen, the Netherlands
| | - Niels P R Anten
- Centre for Crop Systems Analysis, Wageningen University, Postbox 430, 6700 AK, Wageningen, the Netherlands
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21
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Sterck F, Markesteijn L, Toledo M, Schieving F, Poorter L. Sapling performance along resource gradients drives tree species distributions within and across tropical forests. Ecology 2014. [DOI: 10.1890/13-2377.1] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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22
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Dybzinski R, Farrior CE, Ollinger S, Pacala SW. Interspecific vs intraspecific patterns in leaf nitrogen of forest trees across nitrogen availability gradients. THE NEW PHYTOLOGIST 2013; 200:112-121. [PMID: 23738827 DOI: 10.1111/nph.12353] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 05/01/2013] [Indexed: 06/02/2023]
Abstract
Leaf nitrogen content (δ) coordinates with total canopy N and leaf area index (LAI) to maximize whole-crown carbon (C) gain, but the constraints and contributions of within-species plasticity to this phenomenon are poorly understood. Here, we introduce a game theoretic, physiologically based community model of height-structured competition between late-successional tree species. Species are constrained by an increasing, but saturating, relationship between photosynthesis and leaf N per unit leaf area. Higher saturating rates carry higher fixed costs. For a given whole-crown N content, a C gain-maximizing compromise exists between δ and LAI. With greater whole-crown N, both δ and LAI increase within species. However, a shift in community composition caused by reduced understory light at high soil N availability (which competitively favors species with low leaf costs and consequent low optimal δ) counteracts the within-species response, such that community-level δ changes little with soil N availability. These model predictions provide a new explanation for the changes in leaf N per mass observed in data from three dominant broadleaf species in temperate deciduous forests of New England. Attempts to understand large-scale patterns in vegetation often omit competitive interactions and intraspecific plasticity, but here both are essential to an understanding of ecosystem-level patterns.
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Affiliation(s)
- Ray Dybzinski
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Caroline E Farrior
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Scott Ollinger
- Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH, 03824, USA
| | - Stephen W Pacala
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08544, USA
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23
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Zuidema PA, Baker PJ, Groenendijk P, Schippers P, van der Sleen P, Vlam M, Sterck F. Tropical forests and global change: filling knowledge gaps. TRENDS IN PLANT SCIENCE 2013; 18:413-9. [PMID: 23809291 DOI: 10.1016/j.tplants.2013.05.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Revised: 05/16/2013] [Accepted: 05/29/2013] [Indexed: 05/06/2023]
Abstract
Tropical forests will experience major changes in environmental conditions this century. Understanding their responses to such changes is crucial to predicting global carbon cycling. Important knowledge gaps exist: the causes of recent changes in tropical forest dynamics remain unclear and the responses of entire tropical trees to environmental changes are poorly understood. In this Opinion article, we argue that filling these knowledge gaps requires a new research strategy, one that focuses on trees instead of leaves or communities, on long-term instead of short-term changes, and on understanding mechanisms instead of documenting changes. We propose the use of tree-ring analyses, stable-isotope analyses, manipulative field experiments, and well-validated simulation models to improve predictions of forest responses to global change.
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Affiliation(s)
- Pieter A Zuidema
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands.
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24
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Chen H, Wang H, Liu Y, Dong L. Altitudinal variations of ground tissue and xylem tissue in terminal shoot of woody species: implications for treeline formation. PLoS One 2013; 8:e62163. [PMID: 23658621 PMCID: PMC3637301 DOI: 10.1371/journal.pone.0062163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 03/18/2013] [Indexed: 12/04/2022] Open
Abstract
1. The terminal shoot (or current-year shoot), as one of the most active parts on a woody plant, is a basic unit determining plant height and is potentially influenced by a variety of environmental factors. It has been predicted that tissues amount and their allocation in plant stems may play a critical role in determining plant size in alpine regions. The primary structure in terminal shoots is a key to our understanding treeline formation. The existing theories on treeline formation, however, are still largely lacking of evidence at the species level, much less from anatomy for the terminal shoot. 2. The primary structures within terminal shoot were measured quantitatively for 100 species from four elevation zones along the eastern slope of Gongga Mountain, southwestern China; one group was sampled from above the treeline. An allometric approach was employed to examine scaling relationships interspecifically, and a principal components analysis (PCA) was performed to test the relation among primary xylem, ground tissue, species growth form and altitude. 3. The results showed that xylem tissue size was closely correlated with ground tissue size isometrically across species, while undergoing significant y- or/and x-intercept shift in response to altitudinal belts. Further, a conspicuous characteristic of terminal shoot was its allocation of contrasting tissues between primary xylem and ground tissues with increasing elevation. The result of the PCA showed correlations between anatomical variation, species growth form/height classes and environment. 4. The current study presents a comparative assessment of the allocation of tissue in terminal shoot across phylogenically and ecologically diverse species, and analyzes tissue, function and climate associations with plant growth forms and height classes among species. The interspecific connection between primary xylem ratio and plant size along an elevation gradient suggests the importance of primary xylem in explaining the treeline formation.
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Affiliation(s)
- Hong Chen
- Institute of Landscape Ecology of Mountainous Horticulture, Southwest University, Chongqing, China.
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25
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Testo WL, Watkins JE. Influence of plant size on the ecophysiology of the epiphytic fern Asplenium auritum (Aspleniaceae) from Costa Rica. AMERICAN JOURNAL OF BOTANY 2012; 99:1840-1846. [PMID: 23132616 DOI: 10.3732/ajb.1200329] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
PREMISE OF THE STUDY A central goal of plant ecophysiological studies is to generate patterns of physiological behavior that are applicable to a species, which can be complicated when plant size is considered. Studies indicate that plant size can influence numerous ecophysiological parameters, especially in vascular epiphytes. The few studies that have included ferns in their analyses suggest that plant size is less important in ferns than angiosperms. This study investigates this apparent disparity by examining the relationship between plant size and an array of ecophysiological parameters in the epiphytic fern Asplenium auritum, especially the role of plant size in determining responses to water stress. METHODS Plants were classified according to size and measured for a variety of functional traits, including maximum photosynthetic rate, stomatal conductance, water-use efficiency, stomatal density, chlorophyll content, chlorophyll a/b ratio, specific leaf area, whole plant drying rates, and desiccation tolerance. Results for all traits were compared across size classes to determine size-related differences. KEY RESULTS Plant size significantly influenced most traits examined, most notably photosynthetic rate, stomatal density, stomatal conductance, whole plant drying rates, and recovery from desiccation. We report the first evidence of size-mediated shifts in desiccation tolerance in plants: small individuals tolerated water loss, whereas larger individuals avoided desiccation. CONCLUSIONS Our findings indicate that size-mediated ecophysiological shifts are more important than previously thought in ferns, particularly in regard to water relations. Desiccation tolerance may allow young fern sporophytes to establish in stressful environments and is subsequently lost in older individuals.
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Affiliation(s)
- Weston L Testo
- Department of Biology, 13 Oak Drive, Colgate University, Hamilton, New York 13346, USA.
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Way DA, Pearcy RW. Sunflecks in trees and forests: from photosynthetic physiology to global change biology. TREE PHYSIOLOGY 2012; 32:1066-81. [PMID: 22887371 DOI: 10.1093/treephys/tps064] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Sunflecks are brief, intermittent periods of high photon flux density (PFD) that can significantly improve carbon gain in shaded forest understories and lower canopies of trees. In this review, we discuss the physiological basis of leaf-level responses to sunflecks and the mechanisms plants use to tolerate sudden changes in PFD and leaf temperature induced by sunflecks. We also examine the potential effects of climate change stresses (including elevated temperatures, rising CO(2) concentrations and drought) on the ability of tree species to use sunflecks, and advocate more research to improve our predictions of seedling and tree carbon gain in future climates. Lastly, while we have the ability to model realistic responses of photosynthesis to fluctuating PFD, dynamic responses of photosynthesis to sunflecks are not accounted for in current models of canopy carbon uptake, which can lead to substantial overestimates of forest carbon fixation. Since sunflecks are a critical component of seasonal carbon gain for shaded leaves, sunfleck regimes and physiological responses to sunflecks should be incorporated into models to more accurately capture forest carbon dynamics.
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Affiliation(s)
- Danielle A Way
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA.
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27
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Sterck FJ, Martínez-Vilalta J, Mencuccini M, Cochard H, Gerrits P, Zweifel R, Herrero A, Korhonen JF, Llorens P, Nikinmaa E, Nolè A, Poyatos R, Ripullone F, Sass-Klaassen U. Understanding trait interactions and their impacts on growth in Scots pine branches across Europe. Funct Ecol 2012. [DOI: 10.1111/j.1365-2435.2012.01963.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sterck F, Markesteijn L, Schieving F, Poorter L. Functional traits determine trade-offs and niches in a tropical forest community. Proc Natl Acad Sci U S A 2011; 108:20627-32. [PMID: 22106283 PMCID: PMC3251078 DOI: 10.1073/pnas.1106950108] [Citation(s) in RCA: 173] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
How numerous tree species can coexist in diverse forest communities is a key question in community ecology. Whereas neutral theory assumes that species are adapted to common field conditions and coexist by chance, niche theory predicts that species are functionally different and coexist because they are specialized for different niches. We integrated biophysical principles into a mathematical plant model to determine whether and how functional plant traits and trade-offs may cause functional divergence and niche separation of tree species. We used this model to compare the carbon budget of saplings across 13 co-occurring dry-forest tree species along gradients of light and water availability. We found that species ranged in strategy, from acquisitive species with high carbon budgets at highest resource levels to more conservative species with high tolerances for both shade and drought. The crown leaf area index and nitrogen mass per leaf area drove the functional divergence along the simulated light gradient, which was consistent with observed species distributions along light gradients in the forest. Stomatal coordination to avoid low water potentials or hydraulic failure caused functional divergence along the simulated water gradient, but was not correlated to observed species distributions along the water gradient in the forest. The trait-based biophysical model thus explains how functional traits cause functional divergence across species and whether such divergence contributes to niche separation along resource gradients.
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Affiliation(s)
- Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University, 6700 AA, Wageningen, The Netherlands.
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29
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Abstract
Forest canopies exchange a large part of the mass and energy between the earth and the atmosphere. The processes that regulate these exchanges have been of interest to scientists from a diverse range of disciplines for a long time. The International Union of Forest Research Organizations (IUFRO) Canopy Processes Working Group provides a forum for these scientists to explore canopy processes at scales ranging from the leaf to the ecosystem. Given the changes in climate that are being experienced in response to rising [CO(2)], there is a need to understand how forest canopy processes respond to altered environments. Globally, native and managed forests represent the largest terrestrial biome and, in wood and soils, the largest terrestrial stores of carbon. Changing climates have significant implications for carbon storage in forests, as well as their water use, species diversity and management. In order to address these issues, the Canopy Processes Working Group held a travelling workshop in south-east Australia during October 2010 to examine the impact of changing climates on forest canopies, highlighting knowledge gaps and developing new research directions.
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