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Reed CC, Hood SM. Nonstructural carbohydrates explain post-fire tree mortality and recovery patterns. TREE PHYSIOLOGY 2024; 44:tpad155. [PMID: 38123513 DOI: 10.1093/treephys/tpad155] [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: 08/16/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023]
Abstract
Trees use nonstructural carbohydrates (NSCs) to support many functions, including recovery from disturbances. However, NSC's importance for recovery following fire and whether NSC depletion contributes to post-fire delayed mortality are largely unknown. We investigated how fire affects NSCs based on fire-caused injury from a prescribed fire in a young Pinus ponderosa (Lawson & C. Lawson) stand. We assessed crown injury (needle scorch and bud kill) and measured NSCs of needles and inner bark (i.e., secondary phloem) of branches and main stems of trees subject to fire and at an adjacent unburned site. We measured NSCs pre-fire and at six timesteps post-fire (4 days-16 months). While all trees initially survived the fire, NSC concentrations declined quickly in burned trees relative to unburned controls over the same post-fire period. This decline was strongest for trees that eventually died, but those that survived recovered to unburned levels within 14 months post-fire. Two months post-fire, the relationship between crown scorch and NSCs of the main stem inner bark was strongly negative (Adj-R2 = 0.83). Our results support the importance of NSCs for tree survival and recovery post-fire and suggest that post-fire NSC depletion is in part related to reduced photosynthetic leaf area that subsequently limits carbohydrate availability for maintaining tree function. Crown scorch is a commonly measured metric of tree-level fire severity and is often linked to post-fire tree outcome (i.e., recovery or mortality). Thus, our finding that NSC depletion may be the mechanistic link between the fire-caused injury and tree outcome will help improve models of post-fire tree mortality and forest recovery.
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Affiliation(s)
- Charlotte C Reed
- USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, 5775 US Highway 10 W, Missoula, MT 59808, USA
- Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
| | - Sharon M Hood
- USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, 5775 US Highway 10 W, Missoula, MT 59808, USA
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Hillabrand RM, Gordon H, Hynes B, Constabel CP, Landhäusser SM. Populus root salicinoid phenolic glycosides are not mobilized to support metabolism and regrowth under carbon limited conditions. TREE PHYSIOLOGY 2023:tpad020. [PMID: 36809479 DOI: 10.1093/treephys/tpad020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Remobilization of carbon storage compounds in trees is crucial for the resilience to disturbances, stress, and the requirements of their perennial lifestyle, all of which can impact photosynthetic carbon gain. Trees contain abundant non-structural carbohydrates (NSC) in the form of starch and sugars for long term carbon storage, yet questions remain about the ability of trees to remobilize non-conventional carbon compounds under stress. Aspens, like other members of the genus Populus, have abundant specialized metabolites called salicinoid phenolic glycosides, which contain a core glucose moiety. In this study, we hypothesized that the glucose-containing salicinoids could be remobilized as an additional carbon source during severe carbon limitation. We made use of genetically modified hybrid aspen (Populus tremula x P. alba) with minimal salicinoid content and compared these to control plants with high salicinoid content during resprouting (suckering) in dark (carbon limited) conditions. As salicinoids are abundant anti-herbivore compounds, identification of such a secondary function for salicinoids may provide insight to the evolutionary pressures that drive their accumulation. Our results show that salicinoid biosynthesis is maintained during carbon limitation and suggests that salicinoids are not remobilized as a carbon source for regenerating shoot tissue. However, we found that salicinoid-producing aspens had reduced resprouting capacity per available root biomass when compared to salicinoid-deficient aspens. Therefore, our work shows that the constitutive salicinoid production in aspens can reduce the capacity for resprouting and survival in carbon limited conditions.
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Affiliation(s)
- R M Hillabrand
- Department of Renewable Resources, University of Alberta, 442 ESB, Edmonton, Alberta, T6G 2E3, Canada
| | - H Gordon
- Centre for Forest Biology & Department of Biology, University of Victoria, 3800 Finnerty Road, V8P 5C2, Victoria, British Columbia, Canada
| | - B Hynes
- Department of Renewable Resources, University of Alberta, 442 ESB, Edmonton, Alberta, T6G 2E3, Canada
| | - C P Constabel
- Centre for Forest Biology & Department of Biology, University of Victoria, 3800 Finnerty Road, V8P 5C2, Victoria, British Columbia, Canada
| | - S M Landhäusser
- Department of Renewable Resources, University of Alberta, 442 ESB, Edmonton, Alberta, T6G 2E3, Canada
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Oswald SW, Aubrey DP. Modeling starch dynamics from seasonal variations of photosynthesis, growth, and respiration. TREE PHYSIOLOGY 2023:tpad007. [PMID: 36708035 DOI: 10.1093/treephys/tpad007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 11/21/2022] [Indexed: 06/18/2023]
Abstract
Nonstructural carbohydrates (NSCs) buffer differences in plant carbon supply (photosynthesis) and demand (respiration, growth, etc.) but the regulation of their dynamics remains unresolved. Seasonal variations in NSCs are well-documented, but differences in the time-average, amplitude, phase, and other characteristics across ecosystems and functional types lack explanation; furthermore, observed dynamics do not always match expectations. The failure to match observed and expected dynamics has stimulated debate on whether carbon supply or demand drives NSC dynamics. To gain insight into how carbon supply and demand drive seasonal NSC dynamics, we derive a simple model of NSC dynamics based on carbon mass balance and linearizing the NSC demand to determine how supply-driven and demand-driven seasonal NSC dynamics differ. We find that supply-driven and demand-driven dynamics yield distinct timings of seasonal extrema, and supply overrides demand when carbon supply is low in winter (e.g., at high latitudes). Our results also suggest that NSC dynamics often lag changes carbon mass balance. We also predict differences in NSC dynamics across mass, suggesting saplings are more dynamics and respond faster to the environment than mature trees. Our findings suggest substrate-dependent regulation with environmental variation is sufficient to generate complex NSC dynamics.
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Affiliation(s)
- Scott W Oswald
- Savannah River Ecology Lab, Savannah River Site, Jackson, SC, USA
- Warnell School of Forestry, University of Georgia, Athens, GA, USA
| | - Doug P Aubrey
- Savannah River Ecology Lab, Savannah River Site, Jackson, SC, USA
- Warnell School of Forestry, University of Georgia, Athens, GA, USA
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Li Y, Sun H, de Paula Protásio T, Hein PRG, Du B. The mechanisms and prediction of non-structural carbohydrates accretion and depletion after mechanical wounding in slash pine (Pinus elliottii) using near-infrared reflectance spectroscopy. PLANT METHODS 2022; 18:107. [PMID: 36050789 PMCID: PMC9434866 DOI: 10.1186/s13007-022-00939-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND The allocation of non-structural carbohydrates (NSCs) plays a critical role in the physiology and metabolism of tree growth and survival defense. However, little is known about the allocation of NSC after continuous mechanical wounding of pine by resin tapping during tree growth. RESULTS Here, we examine the NSC allocation in plant tissues after 3 year lasting resin tapping, and also investigate the use of near-infrared reflectance (NIR) spectroscopy to quantify the NSC, starch and free sugar (e.g., sucrose, glucose, and fructose) concentrations in different plant tissues of slash pine. Spectral measurements on pine needle, branch, trunk phloem, and root were obtained before starch and free sugar concentrations were measured in the laboratory. The variation of NSC, starch and free sugars in different plant tissues after resin tapping was analyzed. Partial least squares regression was applied to calibrate prediction models, models were simulated 100 times for model performance and error estimation. More NSC, starch and free sugars were stored in winter than summer both in tapped and control trees. The position of resin tapping significantly influenced the NSCs allocation in plant tissues: more NSCs were transformed into free sugars for defensive resin synthesis close to the tapping wound rather than induced distal systemic responses. Models for predicting NSC and free sugars of plant tissues showed promising results for the whole tree for fructose (R2CV = 0.72), glucose (R2CV = 0.67), NSCs (R2CV = 0.66) and starch (R2CV = 0.58) estimates based on NIR models. Models for individual plant tissues also showed reasonable predictive ability: the best model for NSCs and starch prediction was found in root. The significance multivariate correlation algorithm for variable selection significantly reduced the number of variables. Important variables were identified, including features at 1021-1290 nm, 1480, 1748, 1941, 2020, 2123 and 2355 nm, which are highly related to NSC, starch, fructose, glucose and sucrose. CONCLUSIONS NIR spectroscopy provided a rapid and cost-effective method to monitor NSC, starch and free sugar concentrations after continuous resin tapping. It can be used for studying the trade-off between growth and production of defensive metabolites.
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Affiliation(s)
- Yanjie Li
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, China
| | - Honggang Sun
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, China.
| | - Thiago de Paula Protásio
- Federal Rural University of Amazonia-UFRA, Campus Parauapebas, Parauapebas, Pará, 68515-000, Brazil
| | | | - Baoguo Du
- Chair of Tree Physiology, Institute of Forest Sciences, AlbertLudwigs-Universitat Freiburg, Georges-Koehler-Allee 53, 79110, Freiburg, Germany
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Chen Y, Rademacher T, Fonti P, Eckes‐Shephard AH, LeMoine JM, Fonti MV, Richardson AD, Friend AD. Inter-annual and inter-species tree growth explained by phenology of xylogenesis. THE NEW PHYTOLOGIST 2022; 235:939-952. [PMID: 35488501 PMCID: PMC9325364 DOI: 10.1111/nph.18195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 04/15/2022] [Indexed: 05/13/2023]
Abstract
Wood formation determines major long-term carbon (C) accumulation in trees and therefore provides a crucial ecosystem service in mitigating climate change. Nevertheless, we lack understanding of how species with contrasting wood anatomical types differ with respect to phenology and environmental controls on wood formation. In this study, we investigated the seasonality and rates of radial growth and their relationships with climatic factors, and the seasonal variations of stem nonstructural carbohydrates (NSC) in three species with contrasting wood anatomical types (red oak: ring-porous; red maple: diffuse-porous; white pine: coniferous) in a temperate mixed forest during 2017-2019. We found that the high ring width variability observed in both red oak and red maple was caused more by changes in growth duration than growth rate. Seasonal radial growth patterns did not vary following transient environmental factors for all three species. Both angiosperm species showed higher concentrations and lower inter-annual fluctuations of NSC than the coniferous species. Inter-annual variability of ring width varied by species with contrasting wood anatomical types. Due to the high dependence of annual ring width on growth duration, our study highlights the critical importance of xylem formation phenology for understanding and modelling the dynamics of wood formation.
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Affiliation(s)
- Yizhao Chen
- Department of GeographyUniversity of CambridgeCambridgeCB2 3ENUK
| | - Tim Rademacher
- School of Informatics, Computing, and Cyber SystemsNorthern Arizona UniversityFlagstaffAZ86011USA
- Center for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffAZ86011USA
- Harvard ForestHarvard UniversityPetershamMA01366USA
- Institut des Sciences de la Forêt TempéréeUniversité du Québec en OutaouaisRiponQCJOV1V0Canada
| | - Patrick Fonti
- Swiss Federal Research Institute for Forest, Snow and Landscape Research WSLBirmensdorfCH‐8903Switzerland
| | - Annemarie H. Eckes‐Shephard
- Department of GeographyUniversity of CambridgeCambridgeCB2 3ENUK
- Department of Physical Geography and Ecosystem ScienceLund UniversityLundS‐223 62Sweden
| | - James M. LeMoine
- School of Informatics, Computing, and Cyber SystemsNorthern Arizona UniversityFlagstaffAZ86011USA
- Center for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffAZ86011USA
| | - Marina V. Fonti
- Swiss Federal Research Institute for Forest, Snow and Landscape Research WSLBirmensdorfCH‐8903Switzerland
- Institute of Ecology and GeographySiberian Federal UniversitySvobodny pr 79Krasnoyarsk660041Russia
| | - Andrew D. Richardson
- School of Informatics, Computing, and Cyber SystemsNorthern Arizona UniversityFlagstaffAZ86011USA
- Center for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffAZ86011USA
| | - Andrew D. Friend
- Department of GeographyUniversity of CambridgeCambridgeCB2 3ENUK
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Santos M, Nicodemos J, Santos MG. Dynamics of nonstructural carbohydrates in a deciduous woody species from tropical dry forests under recurrent water deficit. PHYSIOLOGIA PLANTARUM 2022; 174:e13632. [PMID: 35060144 DOI: 10.1111/ppl.13632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 01/12/2022] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
In tropical dry forests, both the dry and the short rainy seasons have become increasingly irregular. This study replicated these conditions to investigate the effects of two water deficit cycles on Cenostigma microphyllum seedlings. Impacts were assessed by measuring growth traits, water relations, gas exchange, and dynamics of nonstructural carbohydrate (NSC) content in the whole plant under greenhouse conditions in potted plants. In the first water deficit cycle, the leaf relative water content (RWC) was maintained at the expense of a rapid drop in gas exchange. Furthermore, there was a slight accumulation of NSC, mainly soluble sugars (SS) in the stem wood and roots, to the detriment of height and stem diameter growth. In the second cycle, the leaf RWC remained 40% higher than the lowest level measured in the first water deficit, and CO2 assimilation remained twice as long in previously stressed plants. The SS content of the stems and roots was strongly correlated with the predawn leaf RWC. No strong reduction was observed in the bark stock even with the gradual increase of SS in the wood. Our data suggest that under recurrent water deficit prior to leaf drop, CO2 assimilation is maintained, with the highest possible leaf RWC, under reduced stomatal conductance. This assists in SS transport to wood and root, which is no longer used to support the growth of the aboveground parts.
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Affiliation(s)
- Mariana Santos
- Laboratório de Fisiologia Vegetal, Departamento de Botânica, Universidade Federal de Pernambuco, Recife, Brazil
| | - Joana Nicodemos
- Laboratório de Fisiologia Vegetal, Departamento de Botânica, Universidade Federal de Pernambuco, Recife, Brazil
| | - Mauro G Santos
- Laboratório de Fisiologia Vegetal, Departamento de Botânica, Universidade Federal de Pernambuco, Recife, Brazil
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Li Z, Lathe RS, Li J, He H, Bhalerao RP. Towards understanding the biological foundations of perenniality. TRENDS IN PLANT SCIENCE 2022; 27:56-68. [PMID: 34561180 DOI: 10.1016/j.tplants.2021.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
Perennial life cycles enable plants to have remarkably long lifespans, as exemplified by trees that can live for thousands of years. For this, they require sophisticated regulatory networks that sense environmental changes and initiate adaptive responses in their growth patterns. Recent research has gradually elucidated fundamental mechanisms underlying the perennial life cycle. Intriguingly, several conserved components of the floral transition pathway in annuals such as Arabidopsis thaliana also participate in these regulatory mechanisms underpinning perenniality. Here, we provide an overview of perennials' physiological features and summarise their recently discovered molecular foundations. We also highlight the importance of deepening our understanding of perenniality in the development of perennial grain crops, which are promising elements of future sustainable agriculture.
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Affiliation(s)
- Zheng Li
- State Key Laboratory for Conservation and Utilisation of Bio-Resources in Yunnan, Research Centre for Perennial Rice Engineering and Technology of Yunnan, School of Agriculture, Yunnan University, 650091 Kunming, China.
| | - Rahul S Lathe
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 87 Umeå, Sweden
| | - Jinping Li
- State Key Laboratory for Conservation and Utilisation of Bio-Resources in Yunnan, Research Centre for Perennial Rice Engineering and Technology of Yunnan, School of Agriculture, Yunnan University, 650091 Kunming, China
| | - Hong He
- State Key Laboratory for Conservation and Utilisation of Bio-Resources in Yunnan, Research Centre for Perennial Rice Engineering and Technology of Yunnan, School of Agriculture, Yunnan University, 650091 Kunming, China
| | - Rishikesh P Bhalerao
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 87 Umeå, Sweden.
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Fermaniuk C, Fleurial KG, Wiley E, Landhäusser SM. Large seasonal fluctuations in whole-tree carbohydrate reserves: is storage more dynamic in boreal ecosystems? ANNALS OF BOTANY 2021; 128:943-957. [PMID: 34293090 PMCID: PMC8577199 DOI: 10.1093/aob/mcab099] [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: 06/28/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND AIMS Carbon reserves are a critical source of energy and substrates that allow trees to cope with periods of minimal carbon gain and/or high carbon demands, conditions which are prevalent in high-latitude forests. However, we have a poor understanding of carbon reserve dynamics at the whole-tree level in mature boreal trees. We therefore sought to quantify the seasonal changes in whole-tree and organ-level carbon reserve pools in mature boreal Betula papyrifera. METHODS Non-structural carbohydrate (NSC; soluble sugars and starch) tissue concentrations were measured at key phenological stages throughout a calendar year in the roots, stem (inner bark and xylem), branches and leaves, and scaled up to estimate changes in organ and whole-tree NSC pool sizes. Fine root and stem growth were also measured to compare the timing of growth processes with changes in NSC pools. KEY RESULTS The whole-tree NSC pool increased from its spring minimum to its maximum at bud set, producing an average seasonal fluctuation of 0.96 kg per tree. This fluctuation represents a 72 % change in the whole-tree NSC pool, which greatly exceeds the relative change reported for more temperate conspecifics. At the organ level, branches accounted for roughly 48-60 % of the whole-tree NSC pool throughout the year, and their seasonal fluctuation was four to eight times greater than that observed in the stemwood, coarse roots and inner bark. CONCLUSIONS Branches in boreal B. papyrifera were the largest and most dynamic storage pool, suggesting that storage changes at the branch level largely drive whole-tree storage dynamics in these trees. The greater whole-tree seasonal NSC fluctuation in boreal vs. temperate B. papyrifera may result from (1) higher soluble sugar concentration requirements in branches for frost protection, and/or (2) a larger reliance on reserves to fuel new leaf and shoot growth in the spring.
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Affiliation(s)
- C Fermaniuk
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - K G Fleurial
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - E Wiley
- Department of Biology, University of Central Arkansas, Conway, AR, USA
| | - S M Landhäusser
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
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Piper FI. Putting non-structural compounds on the map of plant life history strategies: a commentary on Schoonmaker et al. TREE PHYSIOLOGY 2021; 41:1559-1562. [PMID: 34274975 DOI: 10.1093/treephys/tpab088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/07/2021] [Indexed: 06/13/2023]
Affiliation(s)
- Frida I Piper
- Instituto de Investigación Interdisciplinario (I3), Universidad de Talca, Campus Lircay, Talca 3460000, Chile
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