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Han Q, Kabeya D, Inagaki Y, Kawasaki T, Satake A. Carbon use strategies in shoot and acorn growth of two evergreen broadleaf trees unraveled by seasonal carbohydrate measurements and carbon isotope analysis. TREE PHYSIOLOGY 2024; 44:221-231. [PMID: 37209131 DOI: 10.1093/treephys/tpad072] [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: 02/27/2023] [Revised: 05/02/2023] [Accepted: 05/15/2023] [Indexed: 05/22/2023]
Abstract
Woody species have evolved carbon (C) storage processes that meet needs for reserves associated with asynchronies between C supply and demand. However, our understanding of storage dynamics is still elusive in mature trees, especially when reproduction is involved. Integrated analyses of isotope ratios, concentrations and biomass may enhance understanding of stored C fractions' dynamics and roles. Thus, we monitored starch and soluble sugars (SSs), C isotope ratios and biomass, in leaves, twigs and reproductive organs of two mature evergreen broadleaf trees, Quercus glauca Thumb. and Lithocarpus edulis Nakai, for 2 years. During the growing season, no starch was observed in twigs, while constant starch levels were observed in leaves. Increase in SSs for winter hardening was earlier in L. edulis than in Q. glauca, in line with L. edulis acorns' earlier ripening. Decrease in SSs and increase in starch occurred simultaneously in the next spring. In addition, sucrose accounted for <10% of total SSs in leaves of both species, whereas mannose accounted for up to 75% in Q. glauca and myo-inositol up to 23% in L. edulis, indicating species-specific sugar composition. These results indicate that seasonal variation of SSs fraction was more reflective of climatic change and nonstructural carbohydrate storage was less influenced by reproduction. No starch was detected in acorn organs of either Q. glauca or L. edulis except in ripening seeds. The biomass of ripe acorns was 1.7- and 6.4-fold greater than that of current-year twigs in Q. glauca and L. edulis, respectively. Bulk twigs and reproductive organs were ca 1.0‰ 13C enriched relative to bulk leaves, which was lower than in deciduous trees. These results indicate that a new photo-assimilate is the predominant C source for reproductive growth. These findings provide new insights into the dynamics of C storage in relation to reproduction in evergreen broadleaf trees.
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Affiliation(s)
- Qingmin Han
- Department of Plant Ecology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Daisuke Kabeya
- Department of Plant Ecology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Yoshiyuki Inagaki
- Shikoku Research Center, Forestry and Forest Products Research Institute, 2-915, Asakuranishi, Kochi 780-8077, Japan
| | - Tatsuro Kawasaki
- Department of Plant Ecology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Akiko Satake
- Department of Biology, Faculty of Science, Kyushu University, 744, Motooka, Fukuoka 819-0395, Japan
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Yu YZ, Ma WT, Wang X, Tcherkez G, Schnyder H, Gong XY. Reconciling water-use efficiency estimates from carbon isotope discrimination of leaf biomass and tree rings: nonphotosynthetic fractionation matters. THE NEW PHYTOLOGIST 2024; 244:2225-2238. [PMID: 39360441 DOI: 10.1111/nph.20170] [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: 06/12/2024] [Accepted: 09/16/2024] [Indexed: 10/04/2024]
Abstract
Carbon isotope discrimination (∆) in leaf biomass (∆BL) and tree rings (∆TR) provides important proxies for plant responses to climate change, specifically in terms of intrinsic water-use efficiency (iWUE). However, the nonphotosynthetic 12C/13C fractionation in plant tissues has rarely been quantified and its influence on iWUE estimation remains uncertain. We derived a comprehensive, ∆ based iWUE model (iWUEcom) which includes nonphotosynthetic fractionations (d) and characterized tissue-specific d-values based on global compilations of data of ∆BL, ∆TR and real-time ∆ in leaf photosynthesis (∆online). iWUEcom was further validated with independent datasets. ∆BL was larger than ∆online by 2.53‰, while ∆BL and ∆TR showed a mean offset of 2.76‰, indicating that ∆TR is quantitatively very similar to ∆online. Applying the tissue-specific d-values (dBL = 2.5‰, dTR = 0‰), iWUE estimated from ∆BL aligned well with those estimated from ∆TR or gas exchange. ∆BL and ∆TR showed a consistent iWUE trend with an average CO2 sensitivity of 0.15 ppm ppm-1 during 1975-2015. Accounting for nonphotosynthetic fractionations improves the estimation of iWUE based on isotope records in leaf biomass and tree rings, which is ultimate for inferring changes in carbon and water cycles under historical and future climate.
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Affiliation(s)
- Yong Zhi Yu
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Wei Ting Ma
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Xuming Wang
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Guillaume Tcherkez
- Institut de Recherche en Horticulture et Semences, Université d'Angers, 42 rue Georges Morel, Beaucouzé, 49070, France
- Research School of Biology, ANU College of Sciences, Australian National University, Canberra, ACT, 2601, Australia
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising, 85354, Germany
| | - Xiao Ying Gong
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, 350007, China
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Walthert L, Etzold S, Carminati A, Saurer M, Köchli R, Zweifel R. Coordination between degree of isohydricity and depth of root water uptake in temperate tree species. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174346. [PMID: 38944298 DOI: 10.1016/j.scitotenv.2024.174346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 06/26/2024] [Accepted: 06/26/2024] [Indexed: 07/01/2024]
Abstract
In an increasingly dry environment, it is crucial to understand how tree species use soil water and cope with drought. However, there is still a knowledge gap regarding the relationships between species-specific stomatal behaviour, spatial root distribution, and root water uptake (RWU) dynamics. Our study aimed to investigate above- and below-ground aspects of water use during soil drying periods in four temperate tree species that differ in stomatal behaviour: two isohydric tracheid-bearing conifers, Scots pine and Norway spruce, and two more anisohydric deciduous species, the diffuse-porous European beech, and the ring-porous Downy oak. From 2015 to 2020, soil-tree-atmosphere-continuum parameters were measured for each species in monospecific forests where trees had no access to groundwater. The hourly time series included data on air temperature, vapor pressure deficit, soil water potential, soil hydraulic conductivity, and RWU to a depth of 2 m. Analysis of drought responses included data on stem radius, leaf water potential, estimated osmotically active compounds, and drought damage. Our study reveals an inherent coordination between stomatal regulation, fine root distribution and water uptake. Compared to conifers, the more anisohydric water use of oak and beech was associated with less strict stomatal closure, greater investment in deep roots, four times higher maximum RWU, a shift of RWU to deeper soil layers as the topsoil dried, and a more pronounced soil drying below 1 m depth. Soil hydraulic conductivity started to limit RWU when values fell below 10-3 to 10-5 cm/d, depending on the soil. As drought progressed, oak and beech may also have benefited from their leaf osmoregulatory capacity, but at the cost of xylem embolism with around 50 % loss of hydraulic conductivity when soil water potential dropped below -1.25 MPa. Consideration of species-specific water use is crucial for forest management and vegetation modelling to improve forest resilience to drought.
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Affiliation(s)
- Lorenz Walthert
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland.
| | - Sophia Etzold
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zürich, Universitätsstrasse 16, 8092 Zürich, Switzerland
| | - Matthias Saurer
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Roger Köchli
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Roman Zweifel
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
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Stojanović M, Jocher G, Kowalska N, Szatniewska J, Zavadilová I, Urban O, Čáslavský J, Horáček P, Acosta M, Pavelka M, Marshall JD. Disaggregation of canopy photosynthesis among tree species in a mixed broadleaf forest. TREE PHYSIOLOGY 2024; 44:tpae064. [PMID: 38864558 PMCID: PMC11240116 DOI: 10.1093/treephys/tpae064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 05/22/2024] [Accepted: 06/11/2024] [Indexed: 06/13/2024]
Abstract
Carbon dioxide sequestration from the atmosphere is commonly assessed using the eddy covariance method. Its net flux signal can be decomposed into gross primary production and ecosystem respiration components, but these have seldom been tested against independent methods. In addition, eddy covariance lacks the ability to partition carbon sequestration among individual trees or species within mixed forests. Therefore, we compared gross primary production from eddy covariance versus an independent method based on sap flow and water-use efficiency, as measured by the tissue heat balance method and δ13C of phloem contents, respectively. The latter measurements were conducted on individual trees throughout a growing season in a mixed broadleaf forest dominated by three tree species, namely English oak, narrow-leaved ash and common hornbeam (Quercus robur L., Fraxinus angustifolia Vahl, and Carpinus betulus L., respectively). In this context, we applied an alternative ecophysiological method aimed at verifying the accuracy of a state-of-the-art eddy covariance system while also offering a solution to the partitioning problem. We observed strong agreement in the ecosystem gross primary production estimates (R2 = 0.56; P < 0.0001), with correlation being especially high and nearly on the 1:1 line in the period before the end of July (R2 = 0.85; P < 0.0001). After this period, the estimates of gross primary production began to diverge. Possible reasons for the divergence are discussed, focusing especially on phenology and the limitation of the isotopic data. English oak showed the highest per-tree daily photosynthetic rates among tree species, but the smaller, more abundant common hornbeam contributed most to the stand-level summation, especially early in the spring. These findings provide a rigorous test of the methods and the species-level photosynthesis offers avenues for enhancing forest management aimed at carbon sequestration.
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Affiliation(s)
- Marko Stojanović
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 4a, Brno 603 00, Czech Republic
| | - Georg Jocher
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 4a, Brno 603 00, Czech Republic
- Thünen-Institut für Agrarklimaschutz Bundesallee 68 38116 Braunschweig Germany
| | - Natalia Kowalska
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 4a, Brno 603 00, Czech Republic
| | - Justyna Szatniewska
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 4a, Brno 603 00, Czech Republic
| | - Ina Zavadilová
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 4a, Brno 603 00, Czech Republic
| | - Otmar Urban
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 4a, Brno 603 00, Czech Republic
| | - Josef Čáslavský
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 4a, Brno 603 00, Czech Republic
| | - Petr Horáček
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 4a, Brno 603 00, Czech Republic
| | - Manuel Acosta
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 4a, Brno 603 00, Czech Republic
| | - Marian Pavelka
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 4a, Brno 603 00, Czech Republic
| | - John D Marshall
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 4a, Brno 603 00, Czech Republic
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå 90183, Sweden
- Leibniz-Zentrum für Agrarlandschaftsforschung, Isotope Geochemistry and Gas Fluxes, Müncheberg 15374, Germany
- Department of Geological Sciences, Box 460, Gothenburg University, Gothenburg 40530, Sweden
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Fernandez-Tschieder E, Marshall JD, Binkley D. Carbon budget at the individual-tree scale: dominant Eucalyptus trees partition less carbon belowground. THE NEW PHYTOLOGIST 2024. [PMID: 38641865 DOI: 10.1111/nph.19764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 03/06/2024] [Indexed: 04/21/2024]
Abstract
Large trees in plantations generally produce more wood per unit of resource use than small trees. Two processes may account for this pattern: greater photosynthetic resource use efficiency or greater partitioning of carbon to wood production. We estimated gross primary production (GPP) at the individual scale by combining transpiration with photosynthetic water-use efficiency of Eucalyptus trees. Aboveground production fluxes were estimated using allometric equations and modeled respiration; total belowground carbon fluxes (TBCF) were estimated by subtracting aboveground fluxes from GPP. Partitioning was estimated by dividing component fluxes by GPP. Dominant trees produced almost three times as much wood as suppressed trees. They used 25 ± 10% (mean ± SD) of their photosynthates for wood production, whereas suppressed trees only used 12 ± 2%. By contrast, dominant trees used 27 ± 19% of their photosynthate belowground, whereas suppressed trees used 58 ± 5%. Intermediate trees lay between these extremes. Photosynthetic water-use efficiency of dominant trees was c. 13% greater than the efficiency of suppressed trees. Suppressed trees used more than twice as much of their photosynthate belowground and less than half as much aboveground compared with dominant trees. Differences in carbon partitioning were much greater than differences in GPP or photosynthetic water-use efficiency.
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Affiliation(s)
- Ezequiel Fernandez-Tschieder
- National Institute of Agricultural Technology (INTA), Agricultural Experimental Station of Delta del Paraná, Campana, B2804, Argentina
- Graduate Degree Program in Ecology, Department of Ecosystem Science and Sustainability, Colorado State University, Fort Collins, CO, 80523, USA
| | - John D Marshall
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, 901 83, Sweden
- Leibniz-Zentrum für Agrarlandschaftsforschung, Müncheberg, 15374, Germany
- Department of Geological Sciences, Gothenburg University, Gothenburg, 405 30, Sweden
- Department of Energy and Matter Fluxes, Czech Globe, Belidla, 603 00, Czechia
| | - Dan Binkley
- School of Forestry, Northern Arizona University, Flagstaff, AZ, 86011, USA
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Zhao Y, Yang H, Yan Q, Zhu Z, Wang B, Song Z, Hou S, Zhou Y. n-Alkane 13C/12C indicates differential metabolic controls of fatty lipid chain extension in C3 and C4 grasses. PLANT PHYSIOLOGY 2024; 194:1299-1303. [PMID: 37988573 DOI: 10.1093/plphys/kiad619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 10/03/2023] [Accepted: 10/25/2023] [Indexed: 11/23/2023]
Abstract
Fundamental differences in metabolic control of fatty acids chain extension are reflected in the contrasting carbon isotopic composition profiles of C3 and C4 grasses.
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Affiliation(s)
- Yu Zhao
- Isotopomics in Chemical Biology (ICB), School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China
| | - Hubiao Yang
- Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Qiulin Yan
- Isotopomics in Chemical Biology (ICB), School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China
| | - Zhenyu Zhu
- Isotopomics in Chemical Biology (ICB), School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China
| | - Bo Wang
- Isotopomics in Chemical Biology (ICB), School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China
| | | | - Shengwei Hou
- Department of Ocean Science & Engineering, Southern University of Science & Technology, Shenzhen 518055, China
| | - Youping Zhou
- Department of Ocean Science & Engineering, Southern University of Science & Technology, Shenzhen 518055, China
- Isotopomics in Chemical Biology (ICB), School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China
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Yu YZ, Liu HT, Yang F, Li L, Schäufele R, Tcherkez G, Schnyder H, Gong XY. δ13C of bulk organic matter and cellulose reveal post-photosynthetic fractionation during ontogeny in C4 grass leaves. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1451-1464. [PMID: 37943576 DOI: 10.1093/jxb/erad445] [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: 06/30/2023] [Accepted: 11/04/2023] [Indexed: 11/10/2023]
Abstract
The 13C isotope composition (δ13C) of leaf dry matter is a useful tool for physiological and ecological studies. However, how post-photosynthetic fractionation associated with respiration and carbon export influences δ13C remains uncertain. We investigated the effects of post-photosynthetic fractionation on δ13C of mature leaves of Cleistogenes squarrosa, a perennial C4 grass, in controlled experiments with different levels of vapour pressure deficit and nitrogen supply. With increasing leaf age class, the 12C/13C fractionation of leaf organic matter relative to the δ13C of atmosphere CO2 (ΔDM) increased while that of cellulose (Δcel) was almost constant. The divergence between ΔDM and Δcel increased with leaf age class, with a maximum value of 1.6‰, indicating the accumulation of post-photosynthetic fractionation. Applying a new mass balance model that accounts for respiration and export of photosynthates, we found an apparent 12C/13C fractionation associated with carbon export of -0.5‰ to -1.0‰. Different ΔDM among leaves, pseudostems, daughter tillers, and roots indicate that post-photosynthetic fractionation happens at the whole-plant level. Compared with ΔDM of old leaves, ΔDM of young leaves and Δcel are more reliable proxies for predicting physiological parameters due to the lower sensitivity to post-photosynthetic fractionation and the similar sensitivity in responses to environmental changes.
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Affiliation(s)
- Yong Zhi Yu
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Hai Tao Liu
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- College of Resources and Environment, Henan Agricultural University, Zhengzhou 450046, China
| | - Fang Yang
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- College of Resources and Environment, Jilin Agricultural University, Changchun 130117, China
| | - Lei Li
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Guillaume Tcherkez
- Research School of Biology, ANU Joint College of Science, Australian National University, Canberra ACT 0200, Australia
- Institut de Recherche en Horticulture et Semences, INRAe, Université d'Angers, 42 rue Georges Morel, 49070 Beaucouzé, France
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Xiao Ying Gong
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, China
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Hu Y, Schäfer KVR, Hu S, Zhou W, Xiang D, Zeng Y, Ouyang S, Chen L, Lei P, Deng X, Zhao Z, Fang X, Xiang W. Woody species with higher hydraulic efficiency or lower photosynthetic capacity discriminate more against 13C at the global scale. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168172. [PMID: 37939937 DOI: 10.1016/j.scitotenv.2023.168172] [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: 07/21/2023] [Revised: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 11/10/2023]
Abstract
Leaf carbon isotope composition (δ13C) provides an integrative record on the carbon and water balance of plants over long periods. Photosynthetic ability and hydraulic traits which are highly associated with stomatal behavior could affect leaf δ13C. Association between photosynthetic ability and leaf δ13C has been examined, however, how hydraulic traits influence leaf δ13C has not been fully understood. To fill this gap, we investigated the variations in leaf δ13C among 2591 woody species (547 shrub and 2044 tree species), and analyzed the link of leaf δ13C with leaf photosynthetic and xylem hydraulic traits. Our result showed that leaf δ13C was positively correlated to leaf photosynthetic ability and capacity. For hydraulic traits, leaf δ13C was negatively related to hydraulic conductivity (Ks), xylem pressure inducing 50 % loss of hydraulic conductivity (P50) and vessel diameter (Vdia). Associations of leaf δ13C with xylem hydraulic traits indicate woody species with stronger hydraulic safety discriminated less against 13C, while woody species with higher hydraulic efficiency had more negative leaf δ13C. Shrub species, which showed a lower Vdia and P50, had a significant less negative leaf δ13C than tree species. Furthermore, woody species inhabiting in dry regions discriminated less against 13C than those growing in humid regions. Moreover, leaf δ13C displayed a low phylogenetic signal based on Blomberg's K statistic. Overall, woody species with a higher leaf photosynthetic ability or stronger hydraulic safety system discriminated less against 13C and adopt the provident water use strategy.
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Affiliation(s)
- Yanting Hu
- Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China; Huitong National Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystems in Hunan Province, Huitong, Hunan 438107, China
| | - Karina V R Schäfer
- Department of Earth and Environmental Sciences, Rutgers University, 195 University Avenue, Newark 07102, NJ, USA
| | - Songjiang Hu
- Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China
| | - Wenneng Zhou
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China.
| | - Dong Xiang
- Forestry Bureau of Huaihua Perfecture, Huaihua 418099, Hunan, China
| | - Yelin Zeng
- Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China; Huitong National Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystems in Hunan Province, Huitong, Hunan 438107, China
| | - Shuai Ouyang
- Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China; Huitong National Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystems in Hunan Province, Huitong, Hunan 438107, China
| | - Liang Chen
- Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China; Huitong National Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystems in Hunan Province, Huitong, Hunan 438107, China
| | - Pifeng Lei
- Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China; Huitong National Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystems in Hunan Province, Huitong, Hunan 438107, China
| | - Xiangwen Deng
- Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China; Huitong National Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystems in Hunan Province, Huitong, Hunan 438107, China
| | - Zhonghui Zhao
- Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China; Huitong National Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystems in Hunan Province, Huitong, Hunan 438107, China
| | - Xi Fang
- Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China; Huitong National Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystems in Hunan Province, Huitong, Hunan 438107, China
| | - Wenhua Xiang
- Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China; Huitong National Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystems in Hunan Province, Huitong, Hunan 438107, China.
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9
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Salomón RL, Rodríguez-Calcerrada J, De Roo L, Miranda JC, Bodé S, Boeckx P, Steppe K. Carbon isotope composition of respired CO2 in woody stems and leafy shoots of three tree species along the growing season: physiological drivers for respiratory fractionation. TREE PHYSIOLOGY 2023; 43:1731-1744. [PMID: 37471648 DOI: 10.1093/treephys/tpad091] [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: 05/30/2023] [Revised: 07/10/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
The carbon isotope composition of respired CO2 (δ13CR) and bulk organic matter (δ13CB) of various plant compartments informs about the isotopic fractionation and substrate of respiratory processes, which are crucial to advance the understanding of carbon allocation in plants. Nevertheless, the variation across organs, species and seasons remains poorly understood. Cavity Ring-Down Laser Spectroscopy was applied to measure δ13CR in leafy shoots and woody stems of maple (Acer platanoides L.), oak (Quercus robur L.) and cedar (Thuja occidentalis L.) trees during spring and late summer. Photosynthesis, respiration, growth and non-structural carbohydrates were measured in parallel to evaluate potential drivers for respiratory fractionation. The CO2 respired by maple and oak shoots was 13C-enriched relative to δ13CB during spring, but not late summer or in the stem. In cedar, δ13CR did not vary significantly throughout organs and seasons, with respired CO2 being 13C-depleted relative to δ13CB. Shoot δ13CR was positively related to leaf starch concentration in maple, while stem δ13CR was inversely related to stem growth. These relations were not significant for oak or cedar. The variability in δ13CR suggests (i) different contributions of respiratory pathways between organs and (ii) seasonality in the respiratory substrate and constitutive compounds for wood formation in deciduous species, less apparent in evergreen cedar, whose respiratory metabolism might be less variable.
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Affiliation(s)
- Roberto L Salomón
- Department of Plants and Crops, Faculty of Bioscience Engineering, Laboratory of Plant Ecology, Ghent University, Coupure links 653, Ghent 9000, Belgium
- Departamento de Sistemas y Recursos Naturales, Research Group FORESCENT, Universidad Politécnica de Madrid, Jose Antonio Novais 10, 28040, Madrid, Spain
| | - Jesús Rodríguez-Calcerrada
- Departamento de Sistemas y Recursos Naturales, Research Group FORESCENT, Universidad Politécnica de Madrid, Jose Antonio Novais 10, 28040, Madrid, Spain
| | - Linus De Roo
- Department of Plants and Crops, Faculty of Bioscience Engineering, Laboratory of Plant Ecology, Ghent University, Coupure links 653, Ghent 9000, Belgium
| | - José Carlos Miranda
- Departamento de Sistemas y Recursos Naturales, Research Group FORESCENT, Universidad Politécnica de Madrid, Jose Antonio Novais 10, 28040, Madrid, Spain
| | - Samuel Bodé
- Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Isotope Bioscience Laboratory - ISOFYS, Ghent University, Coupure links 653, Gent 9000, Belgium
| | - Pascal Boeckx
- Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Isotope Bioscience Laboratory - ISOFYS, Ghent University, Coupure links 653, Gent 9000, Belgium
| | - Kathy Steppe
- Department of Plants and Crops, Faculty of Bioscience Engineering, Laboratory of Plant Ecology, Ghent University, Coupure links 653, Ghent 9000, Belgium
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10
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Li Y, Eugster W, Riedl A, Lehmann MM, Aemisegger F, Buchmann N. Dew benefits on alpine grasslands are cancelled out by combined heatwave and drought stress. FRONTIERS IN PLANT SCIENCE 2023; 14:1136037. [PMID: 37229137 PMCID: PMC10203623 DOI: 10.3389/fpls.2023.1136037] [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: 01/02/2023] [Accepted: 04/04/2023] [Indexed: 05/27/2023]
Abstract
Increasing frequencies of heatwaves combined with simultaneous drought stress in Europe threaten the ecosystem water and carbon budgets of alpine grasslands. Dew as an additional water source can promote ecosystem carbon assimilation. It is known that grassland ecosystems keep high evapotranspiration as long as soil water is available. However, it is rarely being investigated whether dew can mitigate the impact of such extreme climatic events on grassland ecosystem carbon and water exchange. Here we use stable isotopes in meteoric waters and leaf sugars, eddy covariance fluxes for H2O vapor and CO2, in combination with meteorological and plant physiological measurements, to investigate the combined effect of dew and heat-drought stress on plant water status and net ecosystem production (NEP) in an alpine grassland (2000 m elevation) during the June 2019 European heatwave. Before the heatwave, enhanced NEP in the early morning hours can be attributed to leaf wetting by dew. However, dew benefits on NEP were cancelled out by the heatwave, due to the minor contribution of dew in leaf water. Heat-induced reduction in NEP was intensified by the combined effect of drought stress. The recovery of NEP after the peak of the heatwave could be linked to the refilling of plant tissues during nighttime. Among-genera differences of plant water status affected by dew and heat-drought stress can be attributed to differences in their foliar dew water uptake, and their reliance on soil moisture or the impact of the atmospheric evaporative demand. Our results indicate that dew influence on alpine grassland ecosystems varies according to the environmental stress and plant physiology.
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Affiliation(s)
- Yafei Li
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Werner Eugster
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Andreas Riedl
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Marco M. Lehmann
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | | | - Nina Buchmann
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
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11
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Tang Y, Sahlstedt E, Young G, Schiestl‐Aalto P, Saurer M, Kolari P, Jyske T, Bäck J, Rinne‐Garmston KT. Estimating intraseasonal intrinsic water-use efficiency from high-resolution tree-ring δ 13 C data in boreal Scots pine forests. THE NEW PHYTOLOGIST 2023; 237:1606-1619. [PMID: 36451527 PMCID: PMC10108005 DOI: 10.1111/nph.18649] [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: 06/15/2022] [Accepted: 11/16/2022] [Indexed: 05/26/2023]
Abstract
Intrinsic water-use efficiency (iWUE), a key index for carbon and water balance, has been widely estimated from tree-ring δ13 C at annual resolution, but rarely at high-resolution intraseasonal scale. We estimated high-resolution iWUE from laser-ablation δ13 C analysis of tree-rings (iWUEiso ) and compared it with iWUE derived from gas exchange (iWUEgas ) and eddy covariance (iWUEEC ) data for two Pinus sylvestris forests from 2002 to 2019. By carefully timing iWUEiso via modeled tree-ring growth, iWUEiso aligned well with iWUEgas and iWUEEC at intraseasonal scale. However, year-to-year patterns of iWUEgas , iWUEiso , and iWUEEC were different, possibly due to distinct environmental drivers on iWUE across leaf, tree, and ecosystem scales. We quantified the modification of iWUEiso by postphotosynthetic δ13 C enrichment from leaf sucrose to tree rings and by nonexplicit inclusion of mesophyll and photorespiration terms in photosynthetic discrimination model, which resulted in overestimation of iWUEiso by up to 11% and 14%, respectively. We thus extended the application of tree-ring δ13 C for iWUE estimates to high-resolution intraseasonal scale. The comparison of iWUEgas , iWUEiso , and iWUEEC provides important insights into physiological acclimation of trees across leaf, tree, and ecosystem scales under climate change and improves the upscaling of ecological models.
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Affiliation(s)
- Yu Tang
- Bioeconomy and Environment UnitNatural Resources Institute Finland (Luke)Latokartanonkaari 900790HelsinkiFinland
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research (INAR) / Forest SciencesUniversity of HelsinkiPO Box 2700014HelsinkiFinland
| | - Elina Sahlstedt
- Bioeconomy and Environment UnitNatural Resources Institute Finland (Luke)Latokartanonkaari 900790HelsinkiFinland
| | - Giles Young
- Bioeconomy and Environment UnitNatural Resources Institute Finland (Luke)Latokartanonkaari 900790HelsinkiFinland
| | - Pauliina Schiestl‐Aalto
- Faculty of Science, Institute for Atmospheric and Earth System Research (INAR) / PhysicsUniversity of HelsinkiPO Box 6800014HelsinkiFinland
| | - Matthias Saurer
- Forest DynamicsSwiss Federal Institute for Forest, Snow and Landscape Research (WSL)Zürcherstrasse 1118903BirmensdorfSwitzerland
| | - Pasi Kolari
- Faculty of Science, Institute for Atmospheric and Earth System Research (INAR) / PhysicsUniversity of HelsinkiPO Box 6800014HelsinkiFinland
| | - Tuula Jyske
- Production Systems UnitNatural Resources Institute FinlandTietotie 202150EspooFinland
| | - Jaana Bäck
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research (INAR) / Forest SciencesUniversity of HelsinkiPO Box 2700014HelsinkiFinland
| | - Katja T. Rinne‐Garmston
- Bioeconomy and Environment UnitNatural Resources Institute Finland (Luke)Latokartanonkaari 900790HelsinkiFinland
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12
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Ma WT, Yu YZ, Wang X, Gong XY. Estimation of intrinsic water-use efficiency from δ 13C signature of C 3 leaves: Assumptions and uncertainty. FRONTIERS IN PLANT SCIENCE 2023; 13:1037972. [PMID: 36714771 PMCID: PMC9877432 DOI: 10.3389/fpls.2022.1037972] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
Carbon isotope composition (δ13C) has been widely used to estimate the intrinsic water-use efficiency (iWUE) of plants in ecosystems around the world, providing an ultimate record of the functional response of plants to climate change. This approach relies on established relationships between leaf gas exchange and isotopic discrimination, which are reflected in different formulations of 13C-based iWUE models. In the current literature, most studies have utilized the simple, linear equation of photosynthetic discrimination to estimate iWUE. However, recent studies demonstrated that using this linear model for quantitative studies of iWUE could be problematic. Despite these advances, there is a scarcity of review papers that have comprehensively reviewed the theoretical basis, assumptions, and uncertainty of 13C-based iWUE models. Here, we 1) present the theoretical basis of 13C-based iWUE models: the classical model (iWUEsim), the comprehensive model (iWUEcom), and the model incorporating mesophyll conductance (iWUEmes); 2) discuss the limitations of the widely used iWUEsim model; 3) and make suggestions on the application of the iWUEmes model. Finally, we suggest that a mechanistic understanding of mesophyll conductance associated effects and post-photosynthetic fractionation are the bottlenecks for improving the 13C-based estimation of iWUE.
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Affiliation(s)
- Wei Ting Ma
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Yong Zhi Yu
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Xuming Wang
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, Fujian Normal University, Fuzhou, China
| | - Xiao Ying Gong
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, Fujian Normal University, Fuzhou, China
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, China
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13
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Tang Y, Schiestl-Aalto P, Lehmann MM, Saurer M, Sahlstedt E, Kolari P, Leppä K, Bäck J, Rinne-Garmston KT. Estimating intra-seasonal photosynthetic discrimination and water use efficiency using δ13C of leaf sucrose in Scots pine. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:321-335. [PMID: 36255219 PMCID: PMC9786842 DOI: 10.1093/jxb/erac413] [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: 04/25/2022] [Accepted: 10/17/2022] [Indexed: 05/31/2023]
Abstract
Sucrose has a unique role in recording environmental and physiological signals during photosynthesis in its carbon isotope composition (δ13C) and transport of the signal to tree rings. Yet, instead of sucrose, total organic matter (TOM) or water-soluble carbohydrates (WSC) are typically analysed in studies that follow δ13C signals within trees. To study how the choice of organic material may bias the interpretation of δ13C records, we used mature field-grown Scots pine (Pinus sylvestris) to compare for the first time δ13C of different leaf carbon pools with δ13C of assimilates estimated by a chamber-Picarro system (δ13CA_Picarro), and a photosynthetic discrimination model (δ13CA_model). Compared with sucrose, the other tested carbon pools, such as TOM and WSC, poorly recorded the seasonal trends or absolute values of δ13CA_Picarro and δ13CA_model. Consequently, in comparison with the other carbon pools, sucrose δ13C was superior for reconstructing changes in intrinsic water use efficiency (iWUE), agreeing in both absolute values and intra-seasonal variations with iWUE estimated from gas exchange. Thus, deriving iWUE and environmental signals from δ13C of bulk organic matter can lead to misinterpretation. Our findings underscore the advantage of using sucrose δ13C to understand plant physiological responses in depth.
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Affiliation(s)
| | - Paulina Schiestl-Aalto
- Institute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, P.O. Box 68, 00014, Helsinki, Finland
| | - Marco M Lehmann
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - Elina Sahlstedt
- Bioeconomy and Environment Unit, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790, Helsinki, Finland
| | - Pasi Kolari
- Institute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, P.O. Box 68, 00014, Helsinki, Finland
| | - Kersti Leppä
- Bioeconomy and Environment Unit, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790, Helsinki, Finland
| | - Jaana Bäck
- Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, P.O. Box 27, 00014, Helsinki, Finland
| | - Katja T Rinne-Garmston
- Bioeconomy and Environment Unit, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790, Helsinki, Finland
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14
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Leppä K, Tang Y, Ogée J, Launiainen S, Kahmen A, Kolari P, Sahlstedt E, Saurer M, Schiestl‐Aalto P, Rinne‐Garmston KT. Explicitly accounting for needle sugar pool size crucial for predicting intra-seasonal dynamics of needle carbohydrates δ 18 O and δ 13 C. THE NEW PHYTOLOGIST 2022; 236:2044-2060. [PMID: 35575976 PMCID: PMC9795997 DOI: 10.1111/nph.18227] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 05/07/2022] [Indexed: 05/14/2023]
Abstract
We explore needle sugar isotopic compositions (δ18 O and δ13 C) in boreal Scots pine (Pinus sylvestris) over two growing seasons. A leaf-level dynamic model driven by environmental conditions and based on current understanding of isotope fractionation processes was built to predict δ18 O and δ13 C of two hierarchical needle carbohydrate pools, accounting for the needle sugar pool size and the presence of an invariant pinitol pool. Model results agreed well with observed needle water δ18 O, δ18 O and δ13 C of needle water-soluble carbohydrates (sugars + pinitol), and needle sugar δ13 C (R2 = 0.95, 0.84, 0.60, 0.73, respectively). Relative humidity (RH) and intercellular to ambient CO2 concentration ratio (Ci /Ca ) were the dominant drivers of δ18 O and δ13 C variability, respectively. However, the variability of needle sugar δ18 O and δ13 C was reduced on diel and intra-seasonal timescales, compared to predictions based on instantaneous RH and Ci /Ca , due to the large needle sugar pool, which caused the signal formation period to vary seasonally from 2 d to more than 5 d. Furthermore, accounting for a temperature-sensitive biochemical 18 O-fractionation factor and mesophyll resistance in 13 C-discrimination were critical. Interpreting leaf-level isotopic signals requires understanding on time integration caused by mixing in the needle sugar pool.
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Affiliation(s)
- Kersti Leppä
- Natural Resources Institute Finland00790HelsinkiFinland
| | - Yu Tang
- Natural Resources Institute Finland00790HelsinkiFinland
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research (INAR)/Forest SciencesUniversity of Helsinki00014HelsinkiFinland
| | | | | | - Ansgar Kahmen
- Department of Environmental Sciences – BotanyUniversity of Basel4056BaselSwitzerland
| | - Pasi Kolari
- Faculty of Science, Institute for Atmospheric and Earth System Research (INAR)/PhysicsUniversity of Helsinki00014HelsinkiFinland
| | | | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for ForestSnow and Landscape Research (WSL)8903BirmensdorfSwitzerland
| | - Pauliina Schiestl‐Aalto
- Faculty of Science, Institute for Atmospheric and Earth System Research (INAR)/PhysicsUniversity of Helsinki00014HelsinkiFinland
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15
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Martínez‐Sancho E, Treydte K, Lehmann MM, Rigling A, Fonti P. Drought impacts on tree carbon sequestration and water use - evidence from intra-annual tree-ring characteristics. THE NEW PHYTOLOGIST 2022; 236:58-70. [PMID: 35576102 PMCID: PMC9542003 DOI: 10.1111/nph.18224] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/04/2022] [Indexed: 05/22/2023]
Abstract
The impact of climate extremes on forest ecosystems is poorly understood but important for predicting carbon and water cycle feedbacks to climate. Some knowledge gaps still remain regarding how drought-related adjustments in intra-annual tree-ring characteristics directly impact tree carbon and water use. In this study we quantified the impact of an extreme summer drought on the water-use efficiency and carbon sequestration of four mature Norway spruce trees. We used detailed observations of wood formation (xylogenesis) and intra-annual tree-ring properties (quantitative wood anatomy and stable carbon isotopes) combined with physiological water-stress monitoring. During 41 d of tree water deficit, we observed an enrichment in 13 C but a reduction in cell enlargement and wall-thickening processes, which impacted the anatomical characteristics. These adjustments diminished carbon sequestration by 67% despite an 11% increase in water-use efficiency during drought. However, with the resumption of a positive hydric state in the stem, we observed a fast recovery of cell formation rates based on the accumulated assimilates produced during drought. Our findings enhance our understanding of carbon and water fluxes between the atmosphere and forest ecosystems, providing observational evidence on the tree intra-annual carbon sequestration and water-use efficiency dynamics to improve future generations of vegetation models.
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Affiliation(s)
- Elisabet Martínez‐Sancho
- Research Unit Forest DynamicsSwiss Federal Institute for Forest Snow and Landscape Research WSLZürcherstrasse 1118903BirmensdorfSwitzerland
| | - Kerstin Treydte
- Research Unit Forest DynamicsSwiss Federal Institute for Forest Snow and Landscape Research WSLZürcherstrasse 1118903BirmensdorfSwitzerland
| | - Marco M. Lehmann
- Research Unit Forest DynamicsSwiss Federal Institute for Forest Snow and Landscape Research WSLZürcherstrasse 1118903BirmensdorfSwitzerland
| | - Andreas Rigling
- Research Unit Forest DynamicsSwiss Federal Institute for Forest Snow and Landscape Research WSLZürcherstrasse 1118903BirmensdorfSwitzerland
- Institute of Terrestrial EcosystemsSwiss Federal Institute of Technology ETHUniversitaetsstrasse 168092ZurichSwitzerland
| | - Patrick Fonti
- Research Unit Forest DynamicsSwiss Federal Institute for Forest Snow and Landscape Research WSLZürcherstrasse 1118903BirmensdorfSwitzerland
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16
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Environmental Factors at Different Canopy Heights Had Significant Effects on Leaf Water-Use Efficiency in Cold-Temperate Larch Forest. SUSTAINABILITY 2022. [DOI: 10.3390/su14095126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
It is of great significance to study short-term water-use efficiency (WUEs) at different canopy heights for accurately evaluating the adaptability of cold-temperate larch (Larix gmelinii) forest to climate change. The stable isotope method combining data of gradient meteorology, photosynthetic properties and leaf structure were used to assess the influence of different canopy heights on short-term water-use efficiency (WUEs) in larch forests in the northern Da Hinggan Mountains. The results show that: (1) The rank of leaf WUEs at different canopy heights was upper canopy > middle canopy > lower canopy. The leaf WUEs in upper canopy was significantly higher than those in the middle and lower canopy (p < 0.01), and no significant difference was found between the middle and lower canopy (p > 0.05). (2) The environmental factors, the photosynthetic characteristics, the specific leaf weight (LMA) and stomatal density (SD) had significant impact (p < 0.05) on leaf WUEs at different canopy heights of larch forest. (3) The results of the weighted random forest analysis show that the main factor affecting WUEs in larch forests at different canopy heights was vapor pressure deficit (VPD), followed by relative humidity (RH) and net photosynthetic rate (Pn), while LMA and SD made relatively small contributions. This indicates that the variation of leaf WUEs at different canopy heights is mainly due to environmental factors. Our results highlight that the difference of environmental factors at different canopy heights should be considered in the future study of leaf WUE. Our results contribute to a better understanding of water utilization strategies and carbohydrate relations in the boreal forest ecosystems, which is of great significance for improving the sustainable management measures and strategies of boreal forest resources.
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17
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Fiorella RP, Kannenberg SA, Anderegg WRL, Monson RK, Ehleringer JR. Heterogeneous isotope effects decouple conifer leaf and branch sugar δ 18O and δ 13C. Oecologia 2022; 198:357-370. [PMID: 35107645 DOI: 10.1007/s00442-022-05121-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 01/21/2022] [Indexed: 10/19/2022]
Abstract
Isotope ratios of tree-ring cellulose are a prominent tool to reconstruct paleoclimate and plant responses to environmental variation. Current models for cellulose isotope ratios assume a transfer of the environmental signals recorded in bulk leaf water to carbohydrates and ultimately into stem cellulose. However, the isotopic signal of carbohydrates exported from leaf to branch may deviate from mean leaf values if spatial heterogeneity in isotope ratios exists in the leaf. We tested whether the isotopic heterogeneity previously observed along the length of a ponderosa pine (Pinus ponderosa) leaf water was preserved in photosynthetic products. We observed an increase in both sugar and bulk tissue δ18O values along the needle, but the increase in carbohydrate δ18O values was dampened relative to the trend observed in leaf water. In contrast, δ13C values of both sugar and bulk organic matter were invariant along the needle. Phloem-exported sugar measured in the branch below the needles did not match whole-needle values of δ18O or δ13C. Instead, there was a near-constant offset observed between the branch and needle sugar δ13C values, while branch δ18O values were most similar to δ18O values observed for sugar at the base of the needle. The observed offset between the branch and needle sugar δ18O values likely arises from partial isotope oxygen exchange between sugars and water during phloem loading and transport. An improved understanding of the conditions producing differential δ13C and δ18O isotope effects between branch phloem and needle sugars could improve tree-ring-based climate reconstructions.
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Affiliation(s)
- Richard P Fiorella
- Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, 84112, USA.
- Global Change and Sustainability Center, University of Utah, Salt Lake City, UT, 84112, USA.
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
| | - Steven A Kannenberg
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - William R L Anderegg
- Global Change and Sustainability Center, University of Utah, Salt Lake City, UT, 84112, USA
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Russell K Monson
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Laboratory of Tree Ring Research, University of Arizona, Tucson, AZ, 85721, USA
| | - James R Ehleringer
- Global Change and Sustainability Center, University of Utah, Salt Lake City, UT, 84112, USA
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
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18
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Miranda JC, Lehmann MM, Saurer M, Altman J, Treydte K. Insight into Canary Island pine physiology provided by stable isotope patterns of water and plant tissues along an altitudinal gradient. TREE PHYSIOLOGY 2021; 41:1611-1626. [PMID: 33824979 DOI: 10.1093/treephys/tpab046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
The Canary Islands, an archipelago east of Morocco's Atlantic coast, present steep altitudinal gradients covering various climatic zones from hot deserts to subalpine Mediterranean, passing through fog-influenced cloud forests. Unlike the majority of the Canarian flora, Pinus canariensis C. Sm. ex DC. in Buch grow along most of these gradients, allowing the study of plant functioning in contrasting ecosystems. Here we assess the water sources (precipitation, fog) of P. canariensis and its physiological behavior in its different natural environments. We analyzed carbon and oxygen isotope ratios of water and organics from atmosphere, soil and different plant organs and tissues (including 10-year annual time series of tree-ring cellulose) of six sites from 480 to 1990 m above sea level on the Canary Island La Palma. We found a decreasing δ18O trend in source water that was overridden by an increasing δ18O trend in needle water, leaf assimilates and tree-ring cellulose with increasing altitude, suggesting site-specific tree physiological responses to relative humidity. Fog-influenced and fog-free sites showed similar δ13C values, suggesting photosynthetic activity to be limited by stomatal closure and irradiance at certain periods. In addition, we observed an 18O-depletion (fog-free and timberline sites) and 13C-depletion (fog-influenced and fog-free sites) in latewood compared with earlywood caused by seasonal differences in: (i) water uptake (i.e., deeper ground water during summer drought, fog water frequency and interception) and (ii) meteorological conditions (stem radial growth and latewood δ18O correlated with winter precipitation). In addition, we found evidence for foliar water uptake and strong isotopic gradients along the pine needle axis in water and assimilates. These gradients are likely the reason for an unexpected underestimation of pine needle water δ18O when applying standard leaf water δ18O models. Our results indicate that soil water availability and air humidity conditions are the main drivers of the physiological behavior of pine along the Canary Island's altitudinal gradients.
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Affiliation(s)
- José Carlos Miranda
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
- Departamento de Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, 28034 Madrid, Spain
| | - Marco M Lehmann
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Matthias Saurer
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Jan Altman
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
- Institute of Botany, Czech Academy of Science, 25243 Průhonice, Czech Republic
| | - Kerstin Treydte
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
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19
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Eggels S, Blankenagel S, Schön CC, Avramova V. The carbon isotopic signature of C 4 crops and its applicability in breeding for climate resilience. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2021; 134:1663-1675. [PMID: 33575820 PMCID: PMC8205923 DOI: 10.1007/s00122-020-03761-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 12/30/2020] [Indexed: 05/04/2023]
Abstract
KEY MESSAGE Carbon isotope discrimination is a promising trait for indirect screening for improved water use efficiency of C4 crops. In the context of a changing climate, drought is one of the major factors limiting plant growth and yield. Hence, breeding efforts are directed toward improving water use efficiency (WUE) as a key factor in climate resilience and sustainability of crop production. As WUE is a complex trait and its evaluation is rather resource consuming, proxy traits, which are easier to screen and reliably reflect variation in WUE, are needed. In C3 crops, a trait established to be indicative for WUE is the carbon isotopic composition (δ13C) of plant material, which reflects the preferential assimilation of the lighter carbon isotope 12C over 13C during photosynthesis. In C4 crops, carbon fixation is more complex and δ13C thus depends on many more factors than in C3 crops. Recent physiological and genetic studies indicate a correlation between δ13C and WUE also in C4 crops, as well as a colocalization of quantitative trait loci for the two traits. Moreover, significant intraspecific variation as well as a medium to high heritability of δ13C has been shown in some of the main C4 crops, such as maize, sorghum and sugarcane, indicating its potential for indirect selection and breeding. Further research on physiological, genetic and environmental components influencing δ13C is needed to support its application in improving WUE and making C4 crops resilient to climate change.
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Affiliation(s)
- Stella Eggels
- Plant Breeding, TUM School of Life Sciences, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | - Sonja Blankenagel
- Plant Breeding, TUM School of Life Sciences, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | - Chris-Carolin Schön
- Plant Breeding, TUM School of Life Sciences, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | - Viktoriya Avramova
- Plant Breeding, TUM School of Life Sciences, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany.
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20
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Gimeno TE, Campany CE, Drake JE, Barton CVM, Tjoelker MG, Ubierna N, Marshall JD. Whole-tree mesophyll conductance reconciles isotopic and gas-exchange estimates of water-use efficiency. THE NEW PHYTOLOGIST 2021; 229:2535-2547. [PMID: 33217000 DOI: 10.1111/nph.17088] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 11/07/2020] [Indexed: 06/11/2023]
Abstract
Photosynthetic water-use efficiency (WUE) describes the link between terrestrial carbon (C) and water cycles. Estimates of intrinsic WUE (iWUE) from gas exchange and C isotopic composition (δ13 C) differ due to an internal conductance in the leaf mesophyll (gm ) that is variable and seldom computed. We present the first direct estimates of whole-tree gm , together with iWUE from whole-tree gas exchange and δ13 C of the phloem (δ13 Cph ). We measured gas exchange, online 13 C-discrimination, and δ13 Cph monthly throughout spring, summer, and autumn in Eucalyptus tereticornis grown in large whole-tree chambers. Six trees were grown at ambient temperatures and six at a 3°C warmer air temperature; a late-summer drought was also imposed. Drought reduced whole-tree gm . Warming had few direct effects, but amplified drought-induced reductions in whole-tree gm . Whole-tree gm was similar to leaf gm for these same trees. iWUE estimates from δ13 Cph agreed with iWUE from gas exchange, but only after incorporating gm . δ13 Cph was also correlated with whole-tree 13 C-discrimination, but offset by -2.5 ± 0.7‰, presumably due to post-photosynthetic fractionations. We conclude that δ13 Cph is a good proxy for whole-tree iWUE, with the caveats that post-photosynthetic fractionations and intrinsic variability of gm should be incorporated to provide reliable estimates of this trait in response to abiotic stress.
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Affiliation(s)
- Teresa E Gimeno
- Basque Centre for Climate Change (BC3), Leioa, 48940, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48008, Spain
| | - Courtney E Campany
- Department of Biology, Shepherd University, Shepherdstown, WV, 25443, USA
| | - John E Drake
- Forest and Natural Resources Management, SUNY-ESF, Syracuse, NY, 132110, USA
| | - Craig V M Barton
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Mark G Tjoelker
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Nerea Ubierna
- Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
| | - John D Marshall
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Skogsmarksgränd 17, 907 36, Umeå, Sweden
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21
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Wang A, Siegwolf RTW, Joseph J, Thomas FM, Werner W, Gessler A, Rigling A, Schaub M, Saurer M, Li MH, Lehmann MM. Effects of soil moisture, needle age and leaf morphology on carbon and oxygen uptake, incorporation and allocation: a dual labeling approach with 13CO2 and H218O in foliage of a coniferous forest. TREE PHYSIOLOGY 2021; 41:50-62. [PMID: 32879961 DOI: 10.1093/treephys/tpaa114] [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: 05/14/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
The carbon and oxygen isotopic composition of water and assimilates in plants reveals valuable information on plant responses to climatic conditions. Yet, the carbon and oxygen uptake, incorporation and allocation processes determining isotopic compositions are not fully understood. We carried out a dual-isotope labeling experiment at high humidity with 18O-enriched water (H218O) and 13C-enriched CO2 (13CO2) with attached Scots pine (Pinus sylvestris L.) branches and detached twigs of hemiparasitic mistletoes (Viscum album ssp. austriacum) in a naturally dry coniferous forest, where also a long-term irrigation takes place. After 4 h of label exposure, we sampled previous- and recent-year leaves, twig phloem and twig xylem over 192 h for the analysis of isotope ratios in water and assimilates. For both species, the uptake into leaf water and the incorporation of the 18O-label into leaf assimilates was not influenced by soil moisture, while the 13C-label incorporation into assimilates was significantly higher under irrigation compared with control dry conditions. Species-specific differences in leaf morphology or needle age did not affect 18O-label uptake into leaf water, but the incorporation of both tracers into assimilates was two times lower in mistletoe than in pine. The 18O-label allocation in water from pine needles to twig tissues was two times higher for phloem than for xylem under both soil moisture conditions. In contrast, the allocation of both tracers in pine assimilates were similar and not affected by soil moisture, twig tissue or needle age. Soil moisture effects on 13C-label but not on 18O-label incorporation into assimilates can be explained by the stomatal responses at high humidity, non-stomatal pathways for water and isotope exchange reactions. Our results suggest that non-photosynthetic 18O-incorporation processes may have masked prevalent photosynthetic processes. Thus, isotopic variation in leaf water could also be imprinted on assimilates when photosynthetic assimilation rates are low.
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Affiliation(s)
- Ao Wang
- Forest Dynamics, Swiss Federal Research Institute WSL Birmensdorf, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland
- Institute of Terrestrial Ecosystems, ETH Zurich, Universitaetsstrasse 16, 8092 Zurich, Switzerland
| | - Rolf T W Siegwolf
- Forest Dynamics, Swiss Federal Research Institute WSL Birmensdorf, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Jobin Joseph
- Forest Dynamics, Swiss Federal Research Institute WSL Birmensdorf, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Frank M Thomas
- Geobotany, University of Trier, Behringstrasse 21, 54296 Trier, Germany
| | - Willy Werner
- Geobotany, University of Trier, Behringstrasse 21, 54296 Trier, Germany
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Research Institute WSL Birmensdorf, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland
- Institute of Terrestrial Ecosystems, ETH Zurich, Universitaetsstrasse 16, 8092 Zurich, Switzerland
| | - Andreas Rigling
- Forest Dynamics, Swiss Federal Research Institute WSL Birmensdorf, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland
- Institute of Terrestrial Ecosystems, ETH Zurich, Universitaetsstrasse 16, 8092 Zurich, Switzerland
| | - Marcus Schaub
- Forest Dynamics, Swiss Federal Research Institute WSL Birmensdorf, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Research Institute WSL Birmensdorf, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Mai-He Li
- Forest Dynamics, Swiss Federal Research Institute WSL Birmensdorf, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Marco M Lehmann
- Forest Dynamics, Swiss Federal Research Institute WSL Birmensdorf, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland
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22
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Kannenberg SA, Fiorella RP, Anderegg WRL, Monson RK, Ehleringer JR. Seasonal and diurnal trends in progressive isotope enrichment along needles in two pine species. PLANT, CELL & ENVIRONMENT 2021; 44:143-155. [PMID: 33058213 DOI: 10.1111/pce.13915] [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: 05/27/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 06/11/2023]
Abstract
The Craig-Gordon type (C-G) leaf water isotope enrichment models assume a homogeneous distribution of enriched water across the leaf surface, despite observations that Δ18 O can become increasingly enriched from leaf base to tip. Datasets of this 'progressive isotope enrichment' are limited, precluding a comprehensive understanding of (a) the magnitude and variability of progressive isotope enrichment, and (b) how progressive enrichment impacts the accuracy of C-G leaf water model predictions. Here, we present observations of progressive enrichment in two conifer species that capture seasonal and diurnal variability in environmental conditions. We further examine which leaf water isotope models best capture the influence of progressive enrichment on bulk needle water Δ18 O. Observed progressive enrichment was large and equal in magnitude across both species. The magnitude of this effect fluctuated seasonally in concert with vapour pressure deficit, but was static in the face of diurnal cycles in meteorological conditions. Despite large progressive enrichment, three variants of the C-G model reasonably successfully predicted bulk needle Δ18 O. Our results thus suggest that the presence of progressive enrichment does not impact the predictive success of C-G models, and instead yields new insight regarding the physiological and anatomical mechanisms that cause progressive isotope enrichment.
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Affiliation(s)
- Steven A Kannenberg
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Richard P Fiorella
- Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah, USA
| | | | - Russell K Monson
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - James R Ehleringer
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
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23
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Lehmann MM, Egli M, Brinkmann N, Werner RA, Saurer M, Kahmen A. Improving the extraction and purification of leaf and phloem sugars for oxygen isotope analyses. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8854. [PMID: 32511807 DOI: 10.1002/rcm.8854] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/29/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
RATIONALE The oxygen isotopic composition (here shown as the δ18 O value) of soluble sugars in leaves and phloem tissue holds valuable information about plant functions in response to climatic changes. However, δ18 O analysis of sugars is prone to error, and thoroughly tested methods are lacking. METHODS We performed three experiments to test if sample preparation modifies the δ18 O values of sugars. In experiment 1, we tested the effects of oven-drying versus freeze-drying, whereas in experiment 2 we focused on the extraction and purification of leaf sugars. In experiment 3, we investigated the exudation and purification of twig phloem sugars as a function of exudation time and different ethylenediaminetetraacetic acid (EDTA) exudation media. RESULTS Freeze-drying produced more consistent δ18 O values than oven-drying for sucrose but not for phloem sugars. The extraction and purification of leaf sugars can be performed without a significant modification of their δ18 O values; yet the purified leaf and phloem sugars possessed higher δ18 O values than the fraction of water-soluble compounds. Moreover, the exudation time significantly modulated the δ18 O values of phloem sugars, which is probably related to changes in the sugar composition. The addition of EDTA did not improve the determination of the δ18 O values of phloem sugars. CONCLUSIONS We show that the sample preparation of plant sugars for the reliable determination of δ18 O values requires a strict protocol, which is described in this paper. For phloem sugar, we recommend a maximum exudation time of 1 h to reduce the degradation of sucrose and minimise oxygen isotope exchange reactions between the resulting hexoses and water.
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Affiliation(s)
- Marco M Lehmann
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | - Melanie Egli
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
| | - Nadine Brinkmann
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
| | - Roland A Werner
- Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | - Ansgar Kahmen
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
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24
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Vernay A, Tian X, Chi J, Linder S, Mäkelä A, Oren R, Peichl M, Stangl ZR, Tor-Ngern P, Marshall JD. Estimating canopy gross primary production by combining phloem stable isotopes with canopy and mesophyll conductances. PLANT, CELL & ENVIRONMENT 2020; 43:2124-2142. [PMID: 32596814 DOI: 10.1111/pce.13835] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/21/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
Gross primary production (GPP) is a key component of the forest carbon cycle. However, our knowledge of GPP at the stand scale remains uncertain, because estimates derived from eddy covariance (EC) rely on semi-empirical modelling and the assumptions of the EC technique are sometimes not fully met. We propose using the sap flux/isotope method as an alternative way to estimate canopy GPP, termed GPPiso/SF , at the stand scale and at daily resolution. It is based on canopy conductance inferred from sap flux and intrinsic water-use efficiency estimated from the stable carbon isotope composition of phloem contents. The GPPiso/SF estimate was further corrected for seasonal variations in photosynthetic capacity and mesophyll conductance. We compared our estimate of GPPiso/SF to the GPP derived from PRELES, a model parameterized with EC data. The comparisons were performed in a highly instrumented, boreal Scots pine forest in northern Sweden, including a nitrogen fertilized and a reference plot. The resulting annual and daily GPPiso/SF estimates agreed well with PRELES, in the fertilized plot and the reference plot. We discuss the GPPiso/SF method as an alternative which can be widely applied without terrain restrictions, where the assumptions of EC are not met.
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Affiliation(s)
- Antoine Vernay
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Xianglin Tian
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Jinshu Chi
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Sune Linder
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Annikki Mäkelä
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Ram Oren
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
- Division of Environmental Science & Policy, Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
- Department of Civil & Environmental Engineering, Pratt School of Engineering, Duke University, Durham, North Carolina, USA
| | - Matthias Peichl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Zsofia R Stangl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Pantana Tor-Ngern
- Department of Environmental Science, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
- Environment, Health and Social Data Analytics Research Group, Chulalongkorn University, Bangkok, Thailand
| | - John D Marshall
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
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25
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Vadeboncoeur MA, Jennings KA, Ouimette AP, Asbjornsen H. Correcting tree-ring δ13C time series for tree-size effects in eight temperate tree species. TREE PHYSIOLOGY 2020; 40:333-349. [PMID: 31976526 DOI: 10.1093/treephys/tpz138] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 10/16/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
Stable carbon isotope ratios (δ13C) in tree rings have been widely used to study changes in intrinsic water-use efficiency (iWUE), sometimes with limited consideration of how C-isotope discrimination is affected by tree height and canopy position. Our goals were to quantify the relationships between tree size or tree microenvironment and wood δ13C for eight functionally diverse temperate tree species in northern New England and to better understand the physical and physiological mechanisms underlying these differences. We collected short increment cores in closed-canopy stands and analyzed δ13C in the most recent 5 years of growth. We also sampled saplings in both shaded and sun-exposed environments. In closed-canopy stands, we found strong tree-size effects on δ13C, with 3.7-7.2‰ of difference explained by linear regression vs height (0.11-0.28‰ m-1), which in some cases is substantially stronger than the effect reported in previous studies. However, open-grown saplings were often isotopically more similar to large codominant trees than to shade-grown saplings, indicating that light exposure contributes more to the physiological and isotopic differences between small and large trees than does height. We found that in closed-canopy forests, δ13C correlations with diameter at breast height were nonlinear but also strong, allowing a straightforward procedure to correct tree- or stand-scale δ13C-based iWUE chronologies for changing tree size. We demonstrate how to use such data to correct and interpret multi-decadal composite isotope chronologies in both shade-regenerated and open-grown tree cohorts, and we highlight the importance of understanding site history when interpreting δ13C time series.
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Affiliation(s)
- Matthew A Vadeboncoeur
- Earth Systems Research Center, University of New Hampshire, 8 College Road, Durham, NH 03824, USA
| | - Katie A Jennings
- Earth Systems Research Center, University of New Hampshire, 8 College Road, Durham, NH 03824, USA
| | - Andrew P Ouimette
- Earth Systems Research Center, University of New Hampshire, 8 College Road, Durham, NH 03824, USA
| | - Heidi Asbjornsen
- Earth Systems Research Center, University of New Hampshire, 8 College Road, Durham, NH 03824, USA
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Road, Durham, NH 03824, USA
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