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Huang J, Ladd SN, Ingrisch J, Kübert A, Meredith LK, van Haren J, Bamberger I, Daber LE, Kühnhammer K, Bailey K, Hu J, Fudyma J, Shi L, Dippold MA, Meeran K, Miller L, O'Brien MJ, Yang H, Herrera-Ramírez D, Hartmann H, Trumbore S, Bahn M, Werner C, Lehmann MM. The mobilization and transport of newly fixed carbon are driven by plant water use in an experimental rainforest under drought. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:2545-2557. [PMID: 38271585 DOI: 10.1093/jxb/erae030] [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: 08/21/2023] [Accepted: 01/24/2024] [Indexed: 01/27/2024]
Abstract
Non-structural carbohydrates (NSCs) are building blocks for biomass and fuel metabolic processes. However, it remains unclear how tropical forests mobilize, export, and transport NSCs to cope with extreme droughts. We combined drought manipulation and ecosystem 13CO2 pulse-labeling in an enclosed rainforest at Biosphere 2, assessed changes in NSCs, and traced newly assimilated carbohydrates in plant species with diverse hydraulic traits and canopy positions. We show that drought caused a depletion of leaf starch reserves and slowed export and transport of newly assimilated carbohydrates below ground. Drought effects were more pronounced in conservative canopy trees with limited supply of new photosynthates and relatively constant water status than in those with continual photosynthetic supply and deteriorated water status. We provide experimental evidence that local utilization, export, and transport of newly assimilated carbon are closely coupled with plant water use in canopy trees. We highlight that these processes are critical for understanding and predicting tree resistance and ecosystem fluxes in tropical forest under drought.
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Affiliation(s)
- Jianbei Huang
- Max Planck Institute for Biogeochemistry, D-07745 Jena, Germany
| | - S Nemiah Ladd
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
- Department of Environmental Sciences, University of Basel, Bernoullistrasse 30, 4056 Basel, Switzerland
| | - Johannes Ingrisch
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
- Department of Ecology, University of Innsbruck, Sternwartestr 15, 6020 Innsbruck, Austria
| | - Angelika Kübert
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
| | - Laura K Meredith
- School of Natural Resources and the Environment, University of Arizona, 1064 E. Lowell St., Tucson, AZ 85721, USA
- Biosphere 2, University of Arizona, 32540 S. Biosphere Rd, Oracle, AZ 85739, USA
| | - Joost van Haren
- Biosphere 2, University of Arizona, 32540 S. Biosphere Rd, Oracle, AZ 85739, USA
- Honors College, University of Arizona, 1101 East Mabel Street, Tucson, AZ 85719, USA
| | - Ines Bamberger
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
- Atmospheric Chemistry Group, University of Bayreuth (BayCEER), Germany
| | - L Erik Daber
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
| | - Kathrin Kühnhammer
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
| | - Kinzie Bailey
- School of Natural Resources and the Environment, University of Arizona, 1064 E. Lowell St., Tucson, AZ 85721, USA
| | - Jia Hu
- School of Natural Resources and the Environment, University of Arizona, 1064 E. Lowell St., Tucson, AZ 85721, USA
| | - Jane Fudyma
- Department of Environmental Science, University of Arizona, Tucson, AZ, USA
- Department of Land, Air, and Water Resources, University of California, Davis, CA, USA
| | - Lingling Shi
- Biogeochemistry of Agroecosystems, University of Göttingen, Göttingen, Germany
- Geo-Biosphere Interactions, University of Tuebingen, Tuebingen, Germany
| | - Michaela A Dippold
- Biogeochemistry of Agroecosystems, University of Göttingen, Göttingen, Germany
- Geo-Biosphere Interactions, University of Tuebingen, Tuebingen, Germany
| | - Kathiravan Meeran
- Department of Ecology, University of Innsbruck, Sternwartestr 15, 6020 Innsbruck, Austria
| | - Luke Miller
- Biosphere 2, University of Arizona, 32540 S. Biosphere Rd, Oracle, AZ 85739, USA
| | - Michael J O'Brien
- Estación Experimental de Zonas Áridas, Consejo Superior de Investigaciones Científicas, Almería, Spain
| | - Hui Yang
- Max Planck Institute for Biogeochemistry, D-07745 Jena, Germany
| | | | - Henrik Hartmann
- Max Planck Institute for Biogeochemistry, D-07745 Jena, Germany
- Institute for Forest Protection, Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Erwin-Baur-Straße 27, D-06484 Quedlinburg, Germany
| | - Susan Trumbore
- Max Planck Institute for Biogeochemistry, D-07745 Jena, Germany
| | - Michael Bahn
- Department of Ecology, University of Innsbruck, Sternwartestr 15, 6020 Innsbruck, Austria
| | - Christiane Werner
- Ecosystem Physiology, Albert-Ludwig-University of Freiburg, Freiburg, Germany
| | - Marco M Lehmann
- Swiss Federal Research Institute WSL, 8903 Birmensdorf, Switzerland
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Blumstein M. The drivers of intraspecific trait variation and their implications for future tree productivity and survival. AMERICAN JOURNAL OF BOTANY 2024:e16312. [PMID: 38576091 DOI: 10.1002/ajb2.16312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 04/06/2024]
Abstract
Forests are facing unprecedented levels of stress from pest and disease outbreaks, disturbance, fragmentation, development, and a changing climate. These selective agents act to alter forest composition from regional to cellular levels. Thus, a central challenge for understanding how forests will be impacted by future change is how to integrate across scales of biology. Phenotype, or an observable trait, is the product of an individual's genes (G) and the environment in which an organism lives (E). To date, researchers have detailed how environment drives variation in tree phenotypes over long time periods (e.g., long-term ecological research sites [LTERs]) and across large spatial scales (e.g., flux network). In parallel, researchers have discovered the genes and pathways that govern phenotypes, finding high degrees of genetic control and signatures of local adaptation in many plant traits. However, the research in these two areas remain largely independent of each other, hindering our ability to generate accurate predictions of plant response to environment, an increasingly urgent need given threats to forest systems. I present the importance of both genes and environment in determining tree responses to climate stress. I highlight why the difference between G versus E in driving variation is critical for our understanding of climate responses, then propose means of accelerating research that examines G and E simultaneously by leveraging existing long-term, large-scale phenotypic data sets from ecological networks and adding newly affordable sequence (-omics) data to both drill down to find the genes and alleles influencing phenotypes and scale up to find how patterns of demography and local adaptation may influence future response to change.
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Affiliation(s)
- Meghan Blumstein
- Harvard Forest, Harvard University, Petersham, 01366, MA, USA
- Civil and Environmental Engineering, Massachusetts Institute of Technology, 15 Vassar St, Cambridge, 02139, MA, USA
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3
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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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O'Connell BP, Wiley E. Heatwaves do not limit recovery following defoliation but alter leaf drought tolerance traits. PLANT, CELL & ENVIRONMENT 2024; 47:482-496. [PMID: 37877185 DOI: 10.1111/pce.14750] [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: 06/06/2023] [Revised: 09/20/2023] [Accepted: 10/16/2023] [Indexed: 10/26/2023]
Abstract
As heatwave frequency increases, they are more likely to coincide with other disturbances like insect defoliation. But it is unclear if high temperatures after defoliation impact canopy recovery or leaf traits which may affect response to further stressors like drought. To examine these stressor interactions, we subjected defoliated (DEF) and undefoliated (UNDEF) oak saplings to a simulated spring heatwave of +10°C for 25 days. We measured gas exchange, leaf area recovery, carbohydrate storage, turgor loss point (ΨTLP ), and minimum leaf conductance (gmin ). During the heatwave, stem respiration exhibited stronger thermal acclimation in DEF than UNDEF saplings, while stomatal conductance and net photosynthesis increased. The heatwave did not affect leaf area recovery or carbohydrate storage of DEF saplings, but reflush leaves had higher gmin than UNDEF leaves, and this was amplified by the heatwave. Across all treatments, higher gmin was associated with higher daytime stomatal conductance and a lower ΨTLP . The results suggest defoliation stress may not be exacerbated by higher temperatures. However, reflush leaves are less conservative in their water use, limiting their ability to minimise water loss. While lower ΨTLP could help DEF trees maintain gas exchange under mild drought, they may be more vulnerable to dehydration under severe drought.
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Affiliation(s)
| | - Erin Wiley
- Department of Biology, University of Central Arkansas, Conway, Arkansas, USA
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Zhou Q, Shi H, He R, Liu H, Zhu W, Wu S, Zhang Q, Dang H. Climate warming could free cold-adapted trees from C-conservative allocation strategy of storage over growth. GLOBAL CHANGE BIOLOGY 2024; 30:e17016. [PMID: 37921358 DOI: 10.1111/gcb.17016] [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: 06/28/2023] [Revised: 08/11/2023] [Accepted: 10/10/2023] [Indexed: 11/04/2023]
Abstract
Carbon allocation has been fundamental for long-lived trees to survive cold stress at their upper elevation range limit. Although carbon allocation between non-structural carbohydrate (NSC) storage and structural growth is well-documented, it still remains unclear how ongoing climate warming influences these processes, particularly whether these two processes will shift in parallel or respond divergently to warming. Using a combination of an in situ downward-transplant warming experiment and an ex situ chamber warming treatment, we investigated how subalpine fir trees at their upper elevation limit coordinated carbon allocation priority among different sinks (e.g., NSC storage and structural growth) at whole-tree level in response to elevated temperature. We found that transplanted individuals from the upper elevation limit to lower elevations generally induced an increase in specific leaf area, but there was no detected evidence of warming effect on leaf-level saturated photosynthetic rates. Additionally, our results challenged the expectation that climate warming will accelerate structural carbon accumulation while maintaining NSC constant. Instead, individuals favored allocating available carbon to NSC storage over structural growth after 1 year of warming, despite the amplification in total biomass encouraged by both in situ and ex situ experimental warming. Unexpectedly, continued warming drove a regime shift in carbon allocation priority, which was manifested in the increase of NSC storage in synchrony to structural growth enhancement. These findings imply that climate warming would release trees at their cold edge from C-conservative allocation strategy of storage over structural growth. Thus, understanding the strategical regulation of the carbon allocation priority and the distinctive function of carbon sink components is of great implication for predicting tree fate in the future climate warming.
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Affiliation(s)
- Quan Zhou
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Hang Shi
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
| | - Rui He
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Haikun Liu
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wenting Zhu
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- College of Science, Tibet University, Lhasa, China
| | - Shengjun Wu
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Quanfa Zhang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
| | - Haishan Dang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
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Blumstein M, Oseguera M, Caso-McHugh T, Des Marais DL. Nonstructural carbohydrate dynamics' relationship to leaf development under varying environments. THE NEW PHYTOLOGIST 2024; 241:102-113. [PMID: 37882355 DOI: 10.1111/nph.19333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/25/2023] [Indexed: 10/27/2023]
Abstract
Leaf-out in temperate forests is a critical transition point each spring and advancing with global change. The mechanism linking phenological variation to external cues is poorly understood. Nonstructural carbohydrate (NSC) availability may be key. Here, we use branch cuttings from northern red oak (Quercus rubra) and measure NSCs throughout bud development in branch tissue. Given genes and environment influence phenology, we placed branches in an arrayed factorial experiment (three temperatures × two photoperiods, eight genotypes) to examine their impact on variation in leaf-out timing and corresponding NSCs. Despite significant differences in leaf-out timing between treatments, NSC patterns were much more consistent, with all treatments and genotypes displaying similar NSC concentrations across phenophases. Notably, the moderate and hot temperature treatments reached the same NSC concentrations and phenophases at the same growing degree days (GDD), but 20 calendar days apart, while the cold treatment achieved only half the GDD of the other two. Our results suggest that NSCs are coordinated with leaf-out and could act as a molecular clock, signaling to cells the passage of time and triggering leaf development to begin. This link between NSCs and budburst is critical for improving predictions of phenological timing.
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Affiliation(s)
- Meghan Blumstein
- Civil and Environmental Engineering, Massachusetts Institute of Technology, 15 Vassar St., Cambridge, MA, 02139, USA
| | - Miranda Oseguera
- Department of Biology, Saint Joseph's University, 5600 City Avenue, Philadelphia, PA, 19131, USA
| | - Theresa Caso-McHugh
- Civil and Environmental Engineering, Massachusetts Institute of Technology, 15 Vassar St., Cambridge, MA, 02139, USA
| | - David L Des Marais
- Civil and Environmental Engineering, Massachusetts Institute of Technology, 15 Vassar St., Cambridge, MA, 02139, USA
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Fox H, Ben-Dor S, Doron-Faigenboim A, Goldsmith M, Klein T, David-Schwartz R. Carbohydrate dynamics in Populus trees under drought: An expression atlas of genes related to sensing, translocation, and metabolism across organs. PHYSIOLOGIA PLANTARUM 2023; 175:e14001. [PMID: 37882295 DOI: 10.1111/ppl.14001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 07/24/2023] [Accepted: 08/07/2023] [Indexed: 10/27/2023]
Abstract
In trees, nonstructural carbohydrates (NSCs) serve as long-term carbon storage and long-distance carbon transport from source to sink. NSC management in response to drought stress is key to our understanding of drought acclimation. However, the molecular mechanisms underlying these processes remain unclear. By combining a transcriptomic approach with NSC quantification in the leaves, stems, and roots of Populus alba under drought stress, we analyzed genes from 29 gene families related to NSC signaling, translocation, and metabolism. We found starch depletion across organs and accumulation of soluble sugars (SS) in the leaves. Activation of the trehalose-6-phosphate/SNF1-related protein kinase (SnRK1) signaling pathway across organs via the suppression of class I TREHALOSE-PHOSPHATE SYNTHASE (TPS) and the expression of class II TPS genes suggested an active response to drought. The expression of SnRK1α and β subunits, and SUCROSE SYNTHASE6 supported SS accumulation in leaves. The upregulation of active transporters and the downregulation of most passive transporters implied a shift toward active sugar transport and enhanced regulation over partitioning. SS accumulation in vacuoles supports osmoregulation in leaves. The increased expression of sucrose synthesis genes and reduced expression of sucrose degradation genes in the roots did not coincide with sucrose levels, implying local sucrose production for energy. Moreover, the downregulation of invertases in the roots suggests limited sucrose allocation from the aboveground organs. This study provides an expression atlas of NSC-related genes that respond to drought in poplar trees, and can be tested in tree improvement programs for adaptation to drought conditions.
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Affiliation(s)
- Hagar Fox
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Shifra Ben-Dor
- Department of Life Science Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Adi Doron-Faigenboim
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Moshe Goldsmith
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Tamir Klein
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Rakefet David-Schwartz
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
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