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Pan Y, Li F, Lin W, Zhou Y, Song X. Quantifying isotope parameters associated with carbonyl-water oxygen exchange during sucrose translocation in tree phloem. THE NEW PHYTOLOGIST 2024; 242:975-987. [PMID: 38439696 DOI: 10.1111/nph.19654] [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: 11/15/2023] [Accepted: 02/19/2024] [Indexed: 03/06/2024]
Abstract
Stable oxygen isotope ratio of tree-ring α-cellulose (δ18Ocel) yields valuable information on many aspects of tree-climate interactions. However, our current understanding of the mechanistic controls on δ18Ocel is incomplete, with a knowledge gap existent regarding the fractionation effect characterizing carbonyl-water oxygen exchange during sucrose translocation from leaf to phloem. To address this insufficiency, we set up an experimental system integrating a vapor 18O-labeling feature to manipulate leaf-level isotopic signatures in tree saplings enclosed within whole-canopy gas-exchange cuvettes. We applied this experimental system to three different tree species to determine their respective relationships between 18O enrichment of sucrose in leaf lamina (Δ18Ol_suc) and petiole phloem (Δ18Ophl_suc) under environmentally/physiologically stable conditions. Based on the determined Δ18Ophl_suc-Δ18Ol_suc relationships, we estimated that on average, at least 25% of the oxygen atoms in sucrose undergo isotopic exchange with water along the leaf-to-phloem translocation path and that the biochemical fractionation factor accounting for such exchange is c. 34‰, markedly higher than the conventionally assumed value of 27‰. Our study represents a significant step toward quantitative elucidation of the oxygen isotope dynamics during sucrose translocation in trees. This has important implications with respect to improving the δ18Ocel model and its related applications in paleoclimatic and ecophysiological contexts.
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Affiliation(s)
- Yonghui Pan
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
| | - Fang Li
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
- Huzhou Vocational & Technical College, Huzhou, 313000, China
| | - Wen Lin
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Youping Zhou
- Department of Marine Science and Technology, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xin Song
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
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Xiangyang S, Genxu W, Juying S, Shouqin S, Zhaoyong H, Chunlin S, Shan L. Contrasting water sources used by a coniferous forest in the high-altitude, southeastern Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 849:157913. [PMID: 35948127 DOI: 10.1016/j.scitotenv.2022.157913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 08/04/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
Forest trees use various water sources to adapt to environmental conditions in mountainous regions. However, water resources variances along elevational gradients are not clearly understood. This limits the assessment of the ecosystem responses to climate change. In this study, stable oxygen and hydrogen isotopes were used to investigate the spatiotemporal patterns of water sources for Faber's fir in a humid high-altitude elevational gradient (ranging between 2800 m.a.s.l. and 3700 m.a.s.l.) on the southeastern Tibetan Plateau. The results indicated that 27 ± 8.3 % of the xylem water was from previous winter snowmelt between May and June. In contrast, almost all xylem water was from current summer precipitation between July and October. Faber's fir at the lower elevation (2800 m.a.s.l.) primarily relied on water derived from winter precipitation during May and June. Yet, trees located near the tree line (3700 m.a.s.l.) were mostly dependent on current precipitation over the entire growing season. However, when statistically analyzing data from all seven different elevation gradients in this study, the contribution of winter precipitation to xylem water was not elevation dependent. Precipitation contributed to a large proportion (59.86 % ± 33.43 %) of xylem water between May and October. Meanwhile, no linear contribution ratio of precipitation to trees was identified in this high-altitude elevational gradient. The replenishment of soil water and the soil water storage determine the spatiotemporal patterns of water sources. Climate change has the possibility of reducing winter precipitation at high altitudes on the Tibetan Plateau. Thus, tree water use at different altitude gradients will play varied roles in influencing the evolution of forest composition under ongoing climate change.
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Affiliation(s)
- Sun Xiangyang
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China.
| | - Wang Genxu
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China; Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China.
| | - Sun Juying
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China; Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
| | - Sun Shouqin
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Hu Zhaoyong
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Song Chunlin
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Lin Shan
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
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Xu G, Liu X, Hu J, Dorado-Liñán I, Gagen M, Szejner P, Chen T, Trouet V. Intra-annual tree-ring δ18O and δ13C reveal a trade-off between isotopic source and humidity in moist environments. TREE PHYSIOLOGY 2022; 42:2203-2223. [PMID: 35796563 DOI: 10.1093/treephys/tpac076] [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: 10/18/2021] [Accepted: 07/02/2022] [Indexed: 06/15/2023]
Abstract
Tree-ring intra-annual stable isotopes (δ13C and δ18O) are powerful tools for revealing plant ecophysiological responses to climatic extremes. We analyzed interannual and fine-scale intra-annual variability of tree-ring δ13C and δ18O in Chinese red pine (Pinus massoniana) from southeastern China to explore environmental drivers and potential trade-offs between the main physiological controls. We show that wet season relative humidity (May-October RH) drove interannual variability of δ18O and intra-annual variability of tree-ring δ18O. It also drove intra-annual variability of tree-ring δ13C, whereas interannual variability was mainly controlled by February-May temperature and September-October RH. Furthermore, intra-annual tree-ring δ18O variability was larger during wet years compared with dry years, whereas δ13C variability was lower during wet years compared with dry years. As a result of these differences in intra-annual variability amplitude, process-based models (we used the Roden model for δ18O and the Farquhar model for δ13C) captured the intra-annual δ18O pattern better in wet years compared with dry years, whereas intra-annual δ13C pattern was better simulated in dry years compared with wet years. This result suggests a potential asymmetric bias in process-based models in capturing the interplay of the different mechanistic processes (i.e., isotopic source and leaf-level enrichment) operating in dry versus wet years. We therefore propose an intra-annual conceptual model considering a dynamic trade-off between the isotopic source and leaf-level enrichment in different tree-ring parts to understand how climate and ecophysiological processes drive intra-annual tree-ring stable isotopic variability under humid climate conditions.
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Affiliation(s)
- Guobao Xu
- National Field Science Observation and Research Station of Yulong Mountain Cryosphere and Sustainable Development, State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
- Laboratory of Tree-Ring Research, University of Arizona, Tucson 85721, USA
- Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
| | - Xiaohong Liu
- National Field Science Observation and Research Station of Yulong Mountain Cryosphere and Sustainable Development, State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Jia Hu
- Laboratory of Tree-Ring Research, University of Arizona, Tucson 85721, USA
- School of Natural Resources and the Environment, University of Arizona, Tucson 85721, USA
| | - Isabel Dorado-Liñán
- Dpto. de Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, Madrid, Spain
| | - Mary Gagen
- Department of Geography, Swansea University, Singleton Park, Swansea SA28PP, UK
| | - Paul Szejner
- Laboratory of Tree-Ring Research, University of Arizona, Tucson 85721, USA
- Instituto de Geología, Universidad Nacional Autónoma de México, México City 04510, México
| | - Tuo Chen
- National Field Science Observation and Research Station of Yulong Mountain Cryosphere and Sustainable Development, State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Valerie Trouet
- Laboratory of Tree-Ring Research, University of Arizona, Tucson 85721, USA
- School of Natural Resources and the Environment, University of Arizona, Tucson 85721, USA
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Binda G, Di Iorio A, Monticelli D. The what, how, why, and when of dendrochemistry: (paleo)environmental information from the chemical analysis of tree rings. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 758:143672. [PMID: 33277003 DOI: 10.1016/j.scitotenv.2020.143672] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 10/13/2020] [Accepted: 11/02/2020] [Indexed: 05/21/2023]
Abstract
The chemical analysis of tree rings has attracted the interest of researchers in the past five decades in view of the possibility of exploiting this biological indicator as a widely available, high-resolution environmental archive. Information regarding the surrounding environment can be derived either by directly measuring environmental variables (nutrient availability, presence of pollutants, etc.) or by exploiting proxies (e.g. paleoclimatic and paleoenvironmental reconstructions). This review systematically covers the topic and provides a critical view on the reliability of dendrochemical information. First, we introduce the determinable chemical species, such as major elements, trace metals, isotopic ratios, and organic compounds, together with a brief description of their uptake mechanisms and functions in trees. Subsequently, we present the possibilities offered by analytical techniques in the field of tree ring analysis, focusing on direct methods and recent developments. The latter strongly improved the details of the accessible information, enabling the investigation of complex phenomena associated with plant life and encouraging the direct analysis of new analytes, particularly minor organic compounds. With regard to their applications, dendrochemical proxies have been used to trace several processes, such as environmental contamination, paleoclimate reconstruction, global environmental changes, tree physiology, extreme events, ecological trends, and dendroprovenance. Several case studies are discussed for each proposed application, with special emphasis on the reliability of tracing each process. Starting from the reviewed literature data, the second part of the paper is devoted to the critical assessment of the reliability of tree ring proxies. We provide an overview of the current knowledge, discuss the limitations of the inferences that may be drawn from the dendrochemical data, and provide recommendations for the best practices to be used for their validation. Finally, we present the future perspectives related to the advancements in analytical instrumentation and further extension of application fields.
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Affiliation(s)
- Gilberto Binda
- Department of Science and High Technology, Università degli Studi dell'Insubria, Via Valleggio, 12, 22100 Como, Italy
| | - Antonino Di Iorio
- Department of Biotechnology and Life Sciences, Università degli Studi dell'Insubria, Via Jean Henry Dunant, 3, 21100 Varese, Italy
| | - Damiano Monticelli
- Department of Science and High Technology, Università degli Studi dell'Insubria, Via Valleggio, 12, 22100 Como, Italy.
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Schiestl‐Aalto P, Stangl ZR, Tarvainen L, Wallin G, Marshall J, Mäkelä A. Linking canopy-scale mesophyll conductance and phloem sugar δ 13 C using empirical and modelling approaches. THE NEW PHYTOLOGIST 2021; 229:3141-3155. [PMID: 33222199 PMCID: PMC7986199 DOI: 10.1111/nph.17094] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 11/16/2020] [Indexed: 05/26/2023]
Abstract
Interpreting phloem carbohydrate or xylem tissue carbon isotopic composition as measures of water-use efficiency or past tree productivity requires in-depth knowledge of the factors altering the isotopic composition within the pathway from ambient air to phloem contents and tree ring. One of least understood of these factors is mesophyll conductance (gm ). We formulated a dynamic model describing the leaf photosynthetic pathway including seven alternative gm descriptions and a simple transport of sugars from foliage down the trunk. We parameterised the model for a boreal Scots pine stand and compared simulated gm responses with weather variations. We further compared the simulated δ13 C of new photosynthates among the different gm descriptions and against measured phloem sugar δ13 C. Simulated gm estimates of the seven descriptions varied according to weather conditions, resulting in varying estimates of phloem δ13 C during cold/moist and warm/dry periods. The model succeeded in predicting a drought response and a postdrought release in phloem sugar δ13 C indicating suitability of the model for inverse prediction of leaf processes from phloem isotopic composition. We suggest short-interval phloem sampling during and after extreme weather conditions to distinguish between mesophyll conductance drivers for future model development.
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Affiliation(s)
- Pauliina Schiestl‐Aalto
- Institute for Atmospheric and Earth System Research (INAR)/Forest SciencesHelsinki00014Finland
- Department of Forest Ecology and ManagementSLUUmeå901 83Sweden
| | | | - Lasse Tarvainen
- Department of Biological and Environmental SciencesUniversity of GothenburgGothenburg405 30Sweden
| | - Göran Wallin
- Department of Biological and Environmental SciencesUniversity of GothenburgGothenburg405 30Sweden
| | - John Marshall
- Department of Forest Ecology and ManagementSLUUmeå901 83Sweden
| | - Annikki Mäkelä
- Institute for Atmospheric and Earth System Research (INAR)/Forest SciencesHelsinki00014Finland
- Department of Forest Ecology and ManagementSLUUmeå901 83Sweden
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Zhang Y, Chen T, Pei H, Li S, Chen C, Xu G. Similar potential of foliar δ 13C and silicon levels for inferring local climate information in the Tibetan Plateau region. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 704:135461. [PMID: 31810680 DOI: 10.1016/j.scitotenv.2019.135461] [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: 07/29/2019] [Revised: 11/03/2019] [Accepted: 11/08/2019] [Indexed: 06/10/2023]
Abstract
Stable carbon isotope ratios (δ13C) are widely used as climate proxies for assessing and predicting climatic information at an annual resolution. However, the detailed information in the isotopes that results from intra-annual climate scenarios and is associated with mineral accumulation remains unclear. Combined with investigations of elements and ash contents, variations in foliar δ13C in relation to annual, winter and summer climate scenarios were investigated in a dendroclimatologically important tree species Sabina przewalskii Kom. Foliar δ13C exhibited a significant negative correlation with mean annual temperature, mean annual precipitation and mean annual relative humidity as well as significant positive correlations with elevation. Climatic factors in winter and summer have opposite effects on the variation of δ13C. The beneficial mineral element Si had a significant positive correlation with foliar δ13C, whereas the essential mineral elements K, Ca, and Mg did not. Specifically, Si and δ13C have similar correlations with climate factors and elevation. These results suggest that measurement of Si content has a similar potential to δ13C for use as an alternative climate indicator when detailed climatic information may otherwise be limited and provide a basis for understanding the integration of δ13C in plant responses to climate.
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Affiliation(s)
- Youfu Zhang
- Department of Biological Science and Ecology, Henan University of Science and Technology, Luoyang 471003, People's Republic of China.
| | - Tuo Chen
- State Key Laboratory of Cryospheric Sciences, The Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 73000, People's Republic of China.
| | - Huijuan Pei
- Lanzhou Information Center, The Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 73000, People's Republic of China.
| | - Shanjia Li
- School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, People's Republic of China.
| | - Chunyan Chen
- Department of Biological Science and Ecology, Henan University of Science and Technology, Luoyang 471003, People's Republic of China.
| | - Guobao Xu
- State Key Laboratory of Cryospheric Sciences, The Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 73000, People's Republic of China.
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An W, Xu C, Liu X, Tan N, Sano M, Li M, Shao X, Nakatsuka T, Guo Z. Specific response of earlywood and latewood δ 18O from the east and west of Mt. Qomolangma to the Indian summer monsoon. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 689:99-108. [PMID: 31271994 DOI: 10.1016/j.scitotenv.2019.06.268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/31/2019] [Accepted: 06/17/2019] [Indexed: 06/09/2023]
Abstract
This study reports the earlywood and latewood δ18O time series from two hemlock sites located to the east (EQ) and west (WQ) of Mt. Qomolangma (Everest) in the Himalaya. The latewood δ18O series from both sites were highly consistent, whereas the earlywood δ18O values for the two sites show variations over the investigation period. Climate response analysis revealed that the dominant control on latewood δ18O values at both sites was the precipitation amounts of the middle/peak periods of upstream Indian Summer Monsoon (ISM). However, for EQ- and WQ-Earlywood, the main controls were precipitation amounts during the early and middle phases of the upstream ISM, respectively. The upstream amount effect could have accounted for earlywood and latewood δ18O variance. Combined with moisture transport models, we found that source water incorporated into latewood at both sites was derived mainly from the Bay of Bengal and Arabian Sea during middle/peak ISM precipitation. However, during the early ISM, the high ridges of Mt. Qomolangma may block most of the moisture that originates from the Bay of Bengal, which results in a stronger signal of early ISM being recorded in EQ-Earlywood δ18O. The influence of the ISM on WQ-Earlywood is delayed until the middle ISM.
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Affiliation(s)
- Wenling An
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China.
| | - Chenxi Xu
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
| | - Xiaohong Liu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Ning Tan
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Masaki Sano
- Research Institute for Humanity and Nature, Motoyama, Kamigamo, Kitaku, Kyoto, Japan; Faculty of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa 359-1192, Japan
| | - Mingqi Li
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources, Chinese Academy of Sciences, Beijing, China
| | - Xuemei Shao
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Takeshi Nakatsuka
- Research Institute for Humanity and Nature, Motoyama, Kamigamo, Kitaku, Kyoto, Japan
| | - Zhengtang Guo
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China; University of Chinese Academy of Sciences, Beijing, China
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Wernicke J, Stark G, Wang L, Grießinger J, Bräuning A. Air moisture signals in a stable oxygen isotope chronology of dwarf shrubs from the central Tibetan Plateau. ANNALS OF BOTANY 2019; 124:53-64. [PMID: 31329817 PMCID: PMC6676389 DOI: 10.1093/aob/mcz030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 03/12/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND AIMS Annually resolved biological climate proxies beyond the altitudinal and latitudinal distribution limit of trees are rare. In such regions, several studies have demonstrated that annual growth rings of dwarf shrubs are suitable proxies for palaeoclimatic investigations. In High Asia, the pioneer work of Liang et al. (Liang E, Lu X, Ren P, Li X, Zhu L, Eckstein D, 2012. Annual increments of juniper dwarf shrubs above the tree line on the central Tibetan Plateau: a useful climatic proxy. Annals of Botany109: 721-728) confirmed the suitability of shrub growth-ring chronologies for palaeoclimatic research. This study presents the first sensitivity study of an annually resolved δ18O time series inferred from Wilson juniper (Juniperus pingii var. wilsonii) from the northern shoreline of lake Nam Co (Tibetan Plateau). METHODS Based on five individual dwarf shrub discs, a statistically reliable δ18O chronology covering the period 1957-2009 was achieved (expressed population signal = 0.80). Spearman's correlation analysis between the δ18O chronology and climate variables from different sources was applied. In a first step, the suitability of various climate data was evaluated. KEY RESULTS Examinations of climate-proxy relationships revealed significant negative correlations between the δ18O shrub chronology and summer season moisture variability of the previous and current year. In particular, relative humidity of the previous and current vegetation period significantly determined the proxy variability (ρ = -0.48, P < 0.01). Furthermore, the δ18O variability of the developed shrub chronology significantly coincided with a nearby tree-ring δ18O chronology of the same genus (r = 0.62, P < 0.01). CONCLUSIONS The δ18O shrub chronology reliably recorded humidity variations in the Nam Co region. The chronology was significantly correlated with a nearby moisture-sensitive tree-ring δ18O chronology, indicating a common climate signal in the two chronologies. This climate signal was likely determined by moisture variations of the Asian summer monsoon. Local climate effects were superimposed on the supra-regional climate signature of the monsoon circulation. Opposing δ18O values between the two chronologies were interpreted as plant-physiological differences during isotopic fractionation processes.
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Affiliation(s)
- Jakob Wernicke
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Georg Stark
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Lily Wang
- Institute of Geographical Sciences and Natural Resource Research, Chinese Academy of Sciences, Beijing, China
| | - Jussi Grießinger
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Achim Bräuning
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
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A Dual Stable Isotope Approach Unravels Common Climate Signals and Species-Specific Responses to Environmental Change Stored in Multi-Century Tree-Ring Series from the Tibetan Plateau. GEOSCIENCES 2019. [DOI: 10.3390/geosciences9040151] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tree-rings are recorders of environmental signals and are therefore often used to reconstruct past environmental conditions. In this paper, we present four annually resolved, multi-centennial tree-ring isotope series from the southeastern Tibetan plateau. The investigation site, where juniper and spruce trees jointly occur, is one of the highest known tree-stands in the world. Tree ring cellulose oxygen (δ18O) and carbon (δ13C) isotopes were analyzed for a common period of 1685–2007 AD to investigate climate–isotope relationships. Therefore, various climate parameters from a local meteorological station and from the CRU 4.02 dataset were used. Tree-ring δ18O of both species revealed highly significant sensitivities with a high degree of coherence to hydroclimate variables during the growing season. The obtained δ18O–climate relationships can even be retained using a species mean. In contrast, the individual δ13C series indicated a weaker and non-uniform response to the tested variables. Underlying species-specific responses and adaptations to the long-term trend in atmospheric CO2 bias even after a trend correction identified dominant environmental factors triggering the tree-ring δ13C at our site. However, analysis of individual intrinsic water-use efficiency in juniper and spruce trees indicated a species-specific adaptation strategy to climate change.
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Liu X, Zhao L, Voelker S, Xu G, Zeng X, Zhang X, Zhang L, Sun W, Zhang Q, Wu G, Li X. Warming and CO2 enrichment modified the ecophysiological responses of Dahurian larch and Mongolia pine during the past century in the permafrost of northeastern China. TREE PHYSIOLOGY 2019; 39:88-103. [PMID: 29920609 DOI: 10.1093/treephys/tpy060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/03/2018] [Indexed: 06/08/2023]
Abstract
Tree-ring δ13C and δ18O of dominant Dahurian larch and Mongolia pine in the permafrost region of the northern Great Higgnan Mountains, China were used to elucidate species-specific ecophysiological responses to warming temperatures and increasing CO2 over the past century. Larch and pine stable carbon discrimination (Δ13C) 13C and δ18O in tree rings both showed synchronous changes during the investigated period (1901-2010), but with species-specific isotopic responses to atmospheric enriched CO2 and warming. Tree-ring Δ13C and δ18O were controlled by both maximum temperature and moisture conditions (precipitation, relative humidity and vapor pressure deficit), but with different growth periods (Δ13C in June-July and δ18O in July-August, respectively). In addition, stable isotopes of larch showed relatively greater sensitivity to moisture deficits than pine. Climatic conditions from 1920 to 1960 strongly and coherently regulated tree-ring Δ13C and δ18O through stomatal conductance. However, climatic-sensitivities of tree-ring Δ13C and δ18O recently diverged, implying substantial adjustments of stomatal conductance, photosynthetic rate and altered water sources over recent decades, which reveal the varied impacts of each factor on tree-ring Δ13C and δ18O over time. Based on expected changes in leaf gas-exchange, we isolated the impacts of atmospheric CO2 and climate change on intrinsic water-use efficiency (iWUE) over the past century. Higher intracellular CO2 in pine than larch from 1960 onwards suggests this species may be more resilient to severe droughts in the future. Our data also illustrated no weakening of the iWUE response to increasing CO2 in trees from this permafrost region. The overall pattern of CO2 enrichment and climate impacts on iWUE of pine and larch were similar, but warming increased iWUE of larch to a greater extent than that of pine over recent two decades. Taken together, our findings highlight the importance of considering how leaf gas-exchange responses to atmospheric CO2 concentration influence species-specific responses to climate and the alteration of the hydrological environment in forests growing in regions historically dominated by permafrost that will be changing rapidly in response to future warming and increased CO2.
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Affiliation(s)
- Xiaohong Liu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, China
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Liangju Zhao
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an, China
| | - Steven Voelker
- Department of Forest Ecosystems & Society, Oregon State University, Corvallis, USA
| | - Guobao Xu
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Xiaomin Zeng
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, China
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Xuanwen Zhang
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Lingnan Zhang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, China
| | - Weizhen Sun
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Qiuliang Zhang
- Forest College of Inner Mongolia Agricultural University, Huhhot, China
| | - Guoju Wu
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Xiaoqin Li
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, China
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