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Niinemets Ü. Variation in leaf photosynthetic capacity within plant canopies: optimization, structural, and physiological constraints and inefficiencies. PHOTOSYNTHESIS RESEARCH 2023; 158:131-149. [PMID: 37615905 DOI: 10.1007/s11120-023-01043-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 08/04/2023] [Indexed: 08/25/2023]
Abstract
Leaf photosynthetic capacity (light-saturated net assimilation rate, AA) increases from bottom to top of plant canopies as the most prominent acclimation response to the conspicuous within-canopy gradients in light availability. Light-dependent variation in AA through plant canopies is associated with changes in key leaf structural (leaf dry mass per unit leaf area), chemical (nitrogen (N) content per area and dry mass, N partitioning between components of photosynthetic machinery), and physiological (stomatal and mesophyll conductance) traits, whereas the contribution of different traits to within-canopy AA gradients varies across sites, species, and plant functional types. Optimality models maximizing canopy carbon gain for a given total canopy N content predict that AA should be proportionally related to canopy light availability. However, comparison of model expectations with experimental data of within-canopy photosynthetic trait variations in representative plant functional types indicates that such proportionality is not observed in real canopies, and AA vs. canopy light relationships are curvilinear. The factors responsible for deviations from full optimality include stronger stomatal and mesophyll diffusion limitations at higher light, reflecting greater water limitations and more robust foliage in higher light. In addition, limits on efficient packing of photosynthetic machinery within leaf structural scaffolding, high costs of N redistribution among leaves, and limited plasticity of N partitioning among components of photosynthesis machinery constrain AA plasticity. Overall, this review highlights that the variation of AA through plant canopies reflects a complex interplay between adjustments of leaf structure and function to multiple environmental drivers, and that AA plasticity is limited by inherent constraints on and trade-offs between structural, chemical, and physiological traits. I conclude that models trying to simulate photosynthesis gradients in plant canopies should consider co-variations among environmental drivers, and the limitation of functional trait variation by physical constraints and include the key trade-offs between structural, chemical, and physiological leaf characteristics.
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Affiliation(s)
- Ülo Niinemets
- Chair of Plant and Crop Science, Estonian University of Life Sciences, Kreutzwaldi 1, 51011, Tartu, Estonia.
- Estonian Academy of Sciences, Kohtu 6, 10130, Tallinn, Estonia.
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Atkins JW, Walter JA, Stovall AEL, Fahey RT, Gough CM. Power law scaling relationships link canopy structural complexity and height across forest types. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeff W. Atkins
- USDA Forest Service Southern Research Station New Ellenton SC USA
- Department of Biology Virginia Commonwealth University Richmond VA USA
| | - Jonathan A. Walter
- Department of Environmental Sciences University of Virginia Charlottesville VA USA
- Environmental Research Alliance Charlottesville VA USA
| | - Atticus E. L. Stovall
- Biospheric Sciences Laboratory NASA Goddard Space Flight Center Greenbelt MD USA
- Department of Geographical Sciences University of Maryland College Park MD USA
| | - Robert T. Fahey
- Department of Natural Resources and the Environment & Center for Environmental Sciences and Engineering University of Connecticut Storrs CT USA
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Flack-Prain S, Meir P, Malhi Y, Smallman TL, Williams M. Does economic optimisation explain LAI and leaf trait distributions across an Amazon soil moisture gradient? GLOBAL CHANGE BIOLOGY 2021; 27:587-605. [PMID: 32979883 DOI: 10.1111/gcb.15368] [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: 03/06/2020] [Accepted: 08/31/2020] [Indexed: 06/11/2023]
Abstract
Leaf area index (LAI) underpins terrestrial ecosystem functioning, yet our ability to predict LAI remains limited. Across Amazon forests, mean LAI, LAI seasonal dynamics and leaf traits vary with soil moisture stress. We hypothesise that LAI variation can be predicted via an optimality-based approach, using net canopy C export (NCE, photosynthesis minus the C cost of leaf growth and maintenance) as a fitness proxy. We applied a process-based terrestrial ecosystem model to seven plots across a moisture stress gradient with detailed in situ measurements, to determine nominal plant C budgets. For each plot, we then compared observations and simulations of the nominal (i.e. observed) C budget to simulations of alternative, experimental budgets. Experimental budgets were generated by forcing the model with synthetic LAI timeseries (across a range of mean LAI and LAI seasonality) and different leaf trait combinations (leaf mass per unit area, lifespan, photosynthetic capacity and respiration rate) operating along the leaf economic spectrum. Observed mean LAI and LAI seasonality across the soil moisture stress gradient maximised NCE, and were therefore consistent with optimality-based predictions. Yet, the predictive power of an optimality-based approach was limited due to the asymptotic response of simulated NCE to mean LAI and LAI seasonality. Leaf traits fundamentally shaped the C budget, determining simulated optimal LAI and total NCE. Long-lived leaves with lower maximum photosynthetic capacity maximised simulated NCE under aseasonal high mean LAI, with the reverse found for short-lived leaves and higher maximum photosynthetic capacity. The simulated leaf trait LAI trade-offs were consistent with observed distributions. We suggest that a range of LAI strategies could be equally economically viable at local level, though we note several ecological limitations to this interpretation (e.g. between-plant competition). In addition, we show how leaf trait trade-offs enable divergence in canopy strategies. Our results also allow an assessment of the usefulness of optimality-based approaches in simulating primary tropical forest functioning, evaluated against in situ data.
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Affiliation(s)
| | - Patrick Meir
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Yadvinder Malhi
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
| | - Thomas L Smallman
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
- National Centre for Earth Observation, University of Edinburgh, Edinburgh, UK
| | - Mathew Williams
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
- National Centre for Earth Observation, University of Edinburgh, Edinburgh, UK
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Chen X, Sun J, Wang M, Lyu M, Niklas KJ, Michaletz ST, Zhong Q, Cheng D. The Leaf Economics Spectrum Constrains Phenotypic Plasticity Across a Light Gradient. FRONTIERS IN PLANT SCIENCE 2020; 11:735. [PMID: 32595665 PMCID: PMC7300261 DOI: 10.3389/fpls.2020.00735] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 05/07/2020] [Indexed: 05/30/2023]
Abstract
The leaf economics spectrum (LES) characterizes multivariate correlations that confine the global diversity of leaf functional traits onto a single axis of variation. Although LES is well established for traits of sun leaves, it is unclear how well LES characterizes the diversity of traits for shade leaves. Here, we evaluate LES using the sun and shade leaves of 75 woody species sampled at the extremes of a within-canopy light gradient in a subtropical forest. Shading significantly decreased the mean values of LMA and the rates of photosynthesis and dark respiration, but had no discernable effect on nitrogen and phosphorus content. Sun and shade leaves manifested the same relationships among N mass, P mass, A mass, and R mass (i.e., the slopes of log-log scaling relations of LES traits did not differ between sun and shade leaves). However, the difference between the normalization constants of shade and sun leaves was correlated with functional trait plasticity. Although the generality of this finding should be evaluated further using larger datasets comprising more phylogenetically diverse taxa and biomes, these findings support a unified LES across shade as well as sun leaves.
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Affiliation(s)
- Xiaoping Chen
- Fujian Provincial Key Laboratory of Plant Ecophysiology, Fujian Normal University, Fuzhou, China
- Key Laboratory of Humid Subtropical Eco-geographical Process, Ministry of Education, Fuzhou, China
| | - Jun Sun
- Fujian Provincial Key Laboratory of Plant Ecophysiology, Fujian Normal University, Fuzhou, China
| | - Mantang Wang
- School of City and Architecture Engineering, Zaozhuang University, Zaozhuang, China
| | - Min Lyu
- Fujian Provincial Key Laboratory of Plant Ecophysiology, Fujian Normal University, Fuzhou, China
| | - Karl J. Niklas
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, United States
| | - Sean T. Michaletz
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Quanlin Zhong
- Fujian Provincial Key Laboratory of Plant Ecophysiology, Fujian Normal University, Fuzhou, China
| | - Dongliang Cheng
- Fujian Provincial Key Laboratory of Plant Ecophysiology, Fujian Normal University, Fuzhou, China
- Key Laboratory of Humid Subtropical Eco-geographical Process, Ministry of Education, Fuzhou, China
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Gough CM, Atkins JW, Fahey RT, Hardiman BS. High rates of primary production in structurally complex forests. Ecology 2019; 100:e02864. [PMID: 31397885 DOI: 10.1002/ecy.2864] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 07/08/2019] [Accepted: 08/02/2019] [Indexed: 12/19/2022]
Abstract
Structure-function relationships are central to many ecological paradigms. Chief among these is the linkage of net primary production (NPP) with species diversity and canopy structure. Using the National Ecological Observatory Network (NEON) as a subcontinental-scale research platform, we examined how temperate-forest NPP relates to several measures of site-level canopy structure and tree species diversity. Novel multidimensional canopy traits describing structural complexity, most notably canopy rugosity, were more strongly related to site NPP than were species diversity measures and other commonly characterized canopy structural features. The amount of variation in site-level NPP explained by canopy rugosity alone was 83%, which was substantially greater than that explained individually by vegetation area index (31%) or Shannon's index of species diversity (30%). Forests that were more structurally complex, had higher vegetation-area indices, or were more diverse absorbed more light and used light more efficiently to power biomass production, but these relationships were most strongly tied to structural complexity. Implications for ecosystem modeling and management are wide ranging, suggesting structural complexity traits are broad, mechanistically robust indicators of NPP that, in application, could improve the prediction and management of temperate forest carbon sequestration.
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Affiliation(s)
- Christopher M Gough
- Department of Biology, Virginia Commonwealth University, Box 842012, 1000 West Cary Street, Richmond, Virginia, 23284, USA
| | - Jeff W Atkins
- Department of Biology, Virginia Commonwealth University, Box 842012, 1000 West Cary Street, Richmond, Virginia, 23284, USA
| | - Robert T Fahey
- Department of Natural Resources and the Environment, Center for Environmental Sciences and Engineering, University of Connecticut, 1376 Storrs Road, Storrs, Connecticut, 06269, USA
| | - Brady S Hardiman
- Forestry and Natural Resources and Environmental and Ecological Engineering, Purdue University, West Lafayette, Indiana, 47907, USA
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Effects of canopy structure and species diversity on primary production in upper Great Lakes forests. Oecologia 2018; 188:405-415. [DOI: 10.1007/s00442-018-4236-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 07/27/2018] [Indexed: 12/30/2022]
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Yoshinaka K, Nagashima H, Yanagita Y, Hikosaka K. The role of biomass allocation between lamina and petioles in a game of light competition in a dense stand of an annual plant. ANNALS OF BOTANY 2018; 121:1055-1064. [PMID: 29365041 PMCID: PMC5906924 DOI: 10.1093/aob/mcy001] [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: 07/20/2017] [Accepted: 01/02/2018] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS Models of plant three-dimensional (3-D) architecture have been used to find optimal morphological characteristics for light capture or carbon assimilation of a solitary plant. However, optimality theory is not necessarily useful to predict the advantageous strategy of an individual in dense stands, where light capture of an individual is influenced not only by its architecture but also by the architecture of its neighbours. Here, we analysed optimal and evolutionarily stable biomass allocation between the lamina and petiole (evolutionarily stable strategy; ESS) under various neighbour conditions using a 3-D simulation model based on the game theory. METHODS We obtained 3-D information of every leaf of actual Xanthium canadense plants grown in a dense stand using a ruler and a protractor. We calculated light capture and carbon assimilation of an individual plant when it stands alone and when it is surrounded by neighbours in the stand. We considered three trade-offs in petiole length and lamina area: biomass allocation, biomechanical constraints and photosynthesis. Optimal and evolutionarily stable biomass allocation between petiole and lamina were calculated under various neighbour conditions. KEY RESULTS Optimal petiole length varied depending on the presence of neighbours and on the architecture of neighbours. The evolutionarily stable petiole length of plants in the stand tended to be longer than the optimal length of solitary plants. The mean of evolutionarily stable petiole length in the stand was similar to the real one. Trade-offs of biomechanical constraint and photosynthesis had minor effects on optimal and evolutionarily stable petiole length. CONCLUSION Actual plants realize evolutionarily stable architecture in dense stands. Interestingly, there were multiple evolutionarily stable petiole lengths even in one stand, suggesting that plants with different architectures can coexist across plant communities.
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Affiliation(s)
- Kenta Yoshinaka
- Graduate School of Life Sciences, Tohoku University, Aoba, Sendai, Japan
| | - Hisae Nagashima
- Graduate School of Life Sciences, Tohoku University, Aoba, Sendai, Japan
| | | | - Kouki Hikosaka
- Graduate School of Life Sciences, Tohoku University, Aoba, Sendai, Japan
- CREST, JST, Tokyo, Japan
- For correspondence. E-mail
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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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Niinemets Ü. Leaf age dependent changes in within-canopy variation in leaf functional traits: a meta-analysis. JOURNAL OF PLANT RESEARCH 2016; 129:313-38. [PMID: 27033356 PMCID: PMC5818143 DOI: 10.1007/s10265-016-0815-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/23/2016] [Indexed: 05/08/2023]
Abstract
Within-canopy variation in leaf structural and photosynthetic characteristics is a major means by which whole canopy photosynthesis is maximized at given total canopy nitrogen. As key acclimatory modifications, leaf nitrogen content (N A) and photosynthetic capacity (A A) per unit area increase with increasing light availability in the canopy and these increases are associated with increases in leaf dry mass per unit area (M A) and/or nitrogen content per dry mass and/or allocation. However, leaf functional characteristics change with increasing leaf age during leaf development and aging, but the importance of these alterations for within-canopy trait gradients is unknown. I conducted a meta-analysis based on 71 canopies that were sampled at different time periods or, in evergreens, included measurements for different-aged leaves to understand how within-canopy variations in leaf traits (trait plasticity) depend on leaf age. The analysis demonstrated that in evergreen woody species, M A and N A plasticity decreased with increasing leaf age, but the change in A A plasticity was less suggesting a certain re-acclimation of A A to altered light. In deciduous woody species, M A and N A gradients in flush-type species increased during leaf development and were almost invariable through the rest of the season, while in continuously leaf-forming species, the trait gradients increased constantly with increasing leaf age. In forbs, N A plasticity increased, while in grasses, N A plasticity decreased with increasing leaf age, reflecting life form differences in age-dependent changes in light availability and in nitrogen resorption for growth of generative organs. Although more work is needed to improve the coverage of age-dependent plasticity changes in some plant life forms, I argue that the age-dependent variation in trait plasticity uncovered in this study is large enough to warrant incorporation in simulations of canopy photosynthesis through the growing period.
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Affiliation(s)
- Ülo Niinemets
- Department of Plant Physiology, Estonian University of Life Sciences, Kreutzwaldi 1, 51014, Tartu, Estonia.
- Estonian Academy of Sciences, Kohtu 6, 10130, Tallinn, Estonia.
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Niinemets Ü. Within-Canopy Variations in Functional Leaf Traits: Structural, Chemical and Ecological Controls and Diversity of Responses. CANOPY PHOTOSYNTHESIS: FROM BASICS TO APPLICATIONS 2016. [DOI: 10.1007/978-94-017-7291-4_4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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