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Wang Y, Liu X, Treydte K, Zhang Z, Kang H, Zeng X, Xu G, Wu Q, Kang S. Permafrost degradation alters the environmental signals recorded in tree-ring lignin methoxy group δ 2H in northeastern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 860:160519. [PMID: 36442636 DOI: 10.1016/j.scitotenv.2022.160519] [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: 09/24/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 06/16/2023]
Abstract
Climate warming has profoundly altered the status of permafrost and has caused extensive permafrost degradation in the Northern Hemisphere. However, long-term observations investigating the hydrological dynamics of permafrost and its ecological effects on plant growth are lacking. Previous studies have reported tree-ring stable hydrogen isotope ratios of lignin methoxy groups (δ2HLM) as an archive of hydrological signals. This study sampled tree-ring cores from a Larix gmelinii forest in Nanwenghe Forest Park, Northeastern China, and separately measured the tree-ring δ2HLM for earlywood and latewood from 1900 to 2020. Earlywood and latewood δ2HLM values, as well as the difference between them, showed no significant long-term trend from 1900 to 1987; however, they both exhibited significant increasing trends since 1988 at rates of 2.6 ‰ and 4.9 ‰ per decade, respectively. This variance changes the magnitude of the difference between the two chronologies and can be explained by the shift in source water δ2H values during tree growth. Based on a structural equation model analysis, when the influence of permafrost melting weakened due to permafrost degradation, the growing season temperature was better recorded in latewood δ2HLM through the effects of precipitation δ2H from July to September. Based on the environmental response of tree-ring δ2HLM in the permafrost region, permafrost degradation influences the source water δ2H values of trees, thereby affecting the expression of temperature signals in tree-ring δ2HLM. The novel results in this study provide a new perspective on permafrost degradation based on the dynamic responses of tree-ring δ2HLM to source water δ2H during permafrost degradation.
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Affiliation(s)
- Yabo Wang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Xiaohong Liu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China; State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
| | - Kerstin Treydte
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Zhongqiong Zhang
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Huhu Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaomin Zeng
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Guobao Xu
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Qingbai Wu
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Impact of Recent Climate Change on Water-Use Efficiency Strategies of Larix sibirica in the Altai-Sayan Mountain Range. FORESTS 2020. [DOI: 10.3390/f11101103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A strong increase in the mean annual air temperature during the past 50 years by up to 0.54 °C was recorded in the Altai region (45°–52° N; 84°–99° E) compared to the global value of 0.07 °C over the period 1901–2008. The impact of the climatic changes on the hydrology are complex in these mountainous forest ecosystems and not fully understood. We aim to reveal differences in the intrinsic water-use efficiencies (iWUE) strategy by larch (Larix sibirica Ledeb.) derived from stable carbon isotopes at contrasting sites, ranging from the steppe (Ersin, Chadan) to high-elevation (Mongun, Koksu) sites of the Altai over the past century. The iWUE trends increased rapidly for all study sites except Chadan, where a decreasing trend after 2010 has been observed. This decline can be related to increased amount of precipitation compared to increased drought at the other sites. In general, the iWUE is increased up to 14% (1985–2019 compared to 1919–1984), which is lower compared to other studies across the globe likely due to harsh climatic conditions. Vapor pressure deficit and maximal air temperature are impacting Siberian larch significantly and affecting their iWUE differently at the high-elevated and steppe sites of the Altai over the past century.
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Wang Y, Liu X, Anhäuser T, Lu Q, Zeng X, Zhang Q, Wang K, Zhang L, Zhang Y, Keppler F. Temperature signal recorded in δ 2H and δ 13C values of wood lignin methoxyl groups from a permafrost forest in northeastern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 727:138558. [PMID: 32498208 DOI: 10.1016/j.scitotenv.2020.138558] [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: 03/16/2020] [Revised: 04/04/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
Stable isotopes in wood lignin methoxyl groups (δ2HLM and δ13CLM values) have been suggested as valuable complementary paleoclimate proxies. In permafrost forests, tree growth is influenced by multiple factors, however temperature appears to have the strongest impact on tree growth and, therefore, on carbon cycling. To test whether δ2HLM and δ13CLM values of trees from permafrost regions might record climate parameters, two dominant tree species (Larix gmelinii, larch, and Pinus sylvestris var. mongolica, pine) collected from a permafrost forest in China's Greater Hinggan Mountains, were investigated. The two tree species larch and pine covered time spans of 1940 to 2013 and 1870 to 2013, respectively. Results showed significant correlations of pine and larch δ2HLM values and larch δ13CLM values with temperatures and in particular with the mean temperature of the growing season from April to August. However, only weak correlations of δ2HLM and δ13CLM values with moisture conditions, such as precipitation amount and relative humidity were observed. In addition, species specificity in the climate response was most obvious for δ13CLM values. Compared to a temperature reconstruction based on tree ring width, pine δ2HLM-based reconstruction showed strongest spatial correlations with regional temperature. Therefore, δ2HLM values might be a promising proxy to reconstruct growing-season temperatures in permafrost regions.
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Affiliation(s)
- Yabo Wang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Xiaohong Liu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China; State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
| | - Tobias Anhäuser
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany; Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga L5L1C6, Canada
| | - Qiangqiang Lu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China; Xi'an Botanical Garden of Shaanxi Province (Institute of Botany of Shaanxi Province), Xi'an 710061, China
| | - Xiaomin Zeng
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Qiuliang Zhang
- Forest College of Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China
| | - Keyi Wang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Lingnan Zhang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Yu Zhang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany; Heidelberg Center for the Environment HCE, Heidelberg University, D-69120 Heidelberg, Germany
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Influence of Drought on Foliar Water Uptake Capacity of Temperate Tree Species. FORESTS 2019. [DOI: 10.3390/f10070562] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Foliar water uptake (FWU) has been investigated in an increasing number of species from a variety of areas but has remained largely understudied in deciduous, temperate tree species from non-foggy regions. As leaf wetting events frequently occur in temperate regions, FWU might be more important than previously thought and should be investigated. As climate change progresses, the number of drought events is expected to increase, basically resulting in a decreasing number of leaf wetting events, which might make FWU a seemingly less important mechanism. However, the impact of drought on FWU might not be that unidirectional because drought will also cause a more negative tree water potential, which is expected to result in more FWU. It yet remains unclear whether drought results in a general increase or decrease in the amount of water absorbed by leaves. The main objectives of this study are, therefore: (i) to assess FWU-capacity in nine widely distributed key tree species from temperate regions, and (ii) to investigate the effect of drought on FWU in these species. Based on measurements of leaf and soil water potential and FWU-capacity, the effect of drought on FWU in temperate tree species was assessed. Eight out of nine temperate tree species were able to absorb water via their leaves. The amount of water absorbed by leaves and the response of this plant trait to drought were species-dependent, with a general increase in the amount of water absorbed as leaf water potential decreased. This relationship was less pronounced when using soil water potential as an independent variable. We were able to classify species according to their response in FWU to drought at the leaf level, but this classification changed when using drought at the soil level, and was driven by iso- and anisohydric behavior. FWU hence occurred in several key tree species from temperate regions, be it with some variability, which potentially allows these species to partly reduce the effects of drought stress. We recommend including this mechanism in future research regarding plant–water relations and to investigate the impact of different pathways used for FWU.
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Churakova Sidorova OV, Lehmann MM, Siegwolf RTW, Saurer M, Fonti MV, Schmid L, Timofeeva G, Rinne-Garmston KT, Bigler C. Compound-specific carbon isotope patterns in needles of conifer tree species from the Swiss National Park under recent climate change. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 139:264-272. [PMID: 30925436 DOI: 10.1016/j.plaphy.2019.03.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 02/03/2019] [Accepted: 03/08/2019] [Indexed: 06/09/2023]
Abstract
Elevated CO2 along with rising temperature and water deficits can lead to changes in tree physiology and leaf biochemistry. These changes can increase heat- and drought-induced tree mortality. We aim to reveal the impacts of climatic drivers on individual compounds at the leaf level among European larch (Larix decidua) and mountain pine (Pinus mugo) trees, which are widely distributed at high elevations. We investigated seasonal carbon isotope composition (δ13C) and concentration patterns of carbohydrates and organic acids in needles of these two different species from a case study in the Swiss National Park (SNP). We found that average and minimum air temperatures were the main climatic drivers of seasonal variation of δ13C in sucrose and glucose as well as in concentrations of carbohydrates and citric acid/citrate in needles of both tree species. The impact of seasonal climatic drivers on larch and mountain pine trees at the needle level is in line with our earlier study in this region for long-term changes at the tree-ring level. We conclude that the species-specific changes in δ13C and concentrations of carbohydrates and organic acids are sensitive indicators of changes in the metabolic pathways occurring as a result of climatic changes.
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Affiliation(s)
- Olga V Churakova Sidorova
- Forest Ecology, Department of Environmental Systems Science, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; Siberian Federal University, Institute of Ecology and Geography, Laboratory of Ecosystems Biogeochemistry, 660041 Krasnoyarsk, Svobodniy pr 82/6, bld. 25, Russian Federation.
| | - Marco M Lehmann
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Rolf T W Siegwolf
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland; Paul Scherrer Institute, 5232 Villigen - PSI, Switzerland
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland; Paul Scherrer Institute, 5232 Villigen - PSI, Switzerland
| | - Marina V Fonti
- Siberian Federal University, Institute of Ecology and Geography, Laboratory of Ecosystems Biogeochemistry, 660041 Krasnoyarsk, Svobodniy pr 82/6, bld. 25, Russian Federation
| | - Lola Schmid
- Paul Scherrer Institute, 5232 Villigen - PSI, Switzerland
| | - Galina Timofeeva
- Forest Ecology, Department of Environmental Systems Science, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; Paul Scherrer Institute, 5232 Villigen - PSI, Switzerland
| | - Katja T Rinne-Garmston
- Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland
| | - Christof Bigler
- Forest Ecology, Department of Environmental Systems Science, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland
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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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Compound-Specific Carbon Isotopes and Concentrations of Carbohydrates and Organic Acids as Indicators of Tree Decline in Mountain Pine. FORESTS 2018. [DOI: 10.3390/f9060363] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Weigt RB, Streit K, Saurer M, Siegwolf RTW. The influence of increasing temperature and CO2 concentration on recent growth of old-growth larch: contrasting responses at leaf and stem processes derived from tree-ring width and stable isotopes. TREE PHYSIOLOGY 2018; 38:706-720. [PMID: 29194509 DOI: 10.1093/treephys/tpx148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 11/03/2017] [Indexed: 06/07/2023]
Abstract
Time series of tree-ring growth show significant increases since the early 1970s at the alpine tree line, with simultaneously increasing temperatures and atmospheric CO2 concentration. For a comprehensive understanding of this growth change, the physiological response patterns at both the leaf and stem level need to be separately analyzed and identified, and can be retrieved from tree-ring growth and isotope (δ13C, δ18O) series. In this study, we assessed the relative contribution of environmental factors to interannual tree-ring variability by multivariate linear mixed-effects models and the dual isotope approach on a dataset of tree-ring records of ~400-year-old larch (Larix decidua Mill.) from a non-water-limited high-elevation site in the Swiss Alps. The models suggest that summer temperatures and the recent lack of larch budmoth outbreaks were most important for explaining growth variations and trends, while a significant direct effect of the continuously increasing CO2 concentration could not be confirmed. In contrast, δ13C and δ18O, which are strongly influenced by fractionation changes in the leaf, clearly reflected the impact of air humidity (precipitation and vapor pressure deficit) and CO2 concentration: the increase in (δ13C-derived) intrinsic water-use efficiency over the second half of the 20th century suggests an increase in carbon assimilation as a result of enhanced CO2 concentration. The tree-ring δ18O largely reflected recent precipitation as source water, thus indicating a low variability in stomatal conductance, which was confirmed by the dual isotope approach. These leaf-level effects were not reflected in stem growth as they may have been masked by the temperature-caused growth limitation controlling the allocation of increased amounts of photosynthates into wood growth. Our approach demonstrates that the identification of different roles of environmental factors on leaf and stem processes helps to improve the assessment of site-specific changes of carbon fluxes and growth performance under future environmental conditions.
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Affiliation(s)
- Rosemarie B Weigt
- Laboratory of Atmospheric Chemistry, Ecosystem Fluxes, Paul Scherrer Institute, 5232 Villigen, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Kathrin Streit
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Matthias Saurer
- Laboratory of Atmospheric Chemistry, Ecosystem Fluxes, Paul Scherrer Institute, 5232 Villigen, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Rolf T W Siegwolf
- Laboratory of Atmospheric Chemistry, Ecosystem Fluxes, Paul Scherrer Institute, 5232 Villigen, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
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Huber N, Bugmann H, Lafond V. Global sensitivity analysis of a dynamic vegetation model: Model sensitivity depends on successional time, climate and competitive interactions. Ecol Modell 2018. [DOI: 10.1016/j.ecolmodel.2017.12.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Barbeta A, Peñuelas J. Increasing carbon discrimination rates and depth of water uptake favor the growth of Mediterranean evergreen trees in the ecotone with temperate deciduous forests. GLOBAL CHANGE BIOLOGY 2017; 23:5054-5068. [PMID: 28544424 DOI: 10.1111/gcb.13770] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 05/04/2017] [Accepted: 05/16/2017] [Indexed: 05/17/2023]
Abstract
Tree populations at the low-altitudinal or -latitudinal limits of species' distributional ranges are predicted to retreat toward higher altitudes and latitudes to track the ongoing changes in climate. Studies have focused on the climatic sensitivity of the retreating species, whereas little is known about the potential replacements. Competition between tree species in forest ecotones will likely be strongly influenced by the ecophysiological responses to heat and drought. We used tree-ring widths and δ13 C and δ18 O chronologies to compare the growth rates and long-term ecophysiological responses to climate in the temperate-Mediterranean ecotone formed by the deciduous Fagus sylvatica and the evergreen Quercus ilex at the low altitudinal and southern latitudinal limit of F. sylvatica (NE Iberian Peninsula). F. sylvatica growth rates were similar to those of other southern populations and were surprisingly not higher than those of Q. ilex, which were an order of magnitude higher than those in nearby drier sites. Higher Q. ilex growth rates were associated with high temperatures, which have increased carbon discrimination rates in the last 25 years. In contrast, stomatal regulation in F. sylvatica was proportional to the increase in atmospheric CO2 . Tree-ring δ18 O for both species were mostly correlated with δ18 O in the source water. In contrast to many previous studies, relative humidity was not negatively correlated with tree-ring δ18 O but had a positive effect on Q. ilex tree-ring δ18 O. Furthermore, tree-ring δ18 O decreased in Q. ilex over time. The sensitivity of Q. ilex to climate likely reflects the uptake of deep water that allowed it to benefit from the effect of CO2 fertilization, in contrast to the water-limited F. sylvatica. Consequently, Q. ilex is a strong competitor at sites currently dominated by F. sylvatica and could be favored by increasingly warmer conditions.
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Affiliation(s)
- Adrià Barbeta
- ISPA, Bordeaux Science Agro, INRA, Villenave d'Ornon, 33140, France
- Global Ecology Unit CREAF-CSIC-UAB, CSIC, E-08193, Bellaterra, Catalonia, Spain
- CREAF, E-08193, Cerdanyola del Vallès, Catalonia, Spain
| | - Josep Peñuelas
- Global Ecology Unit CREAF-CSIC-UAB, CSIC, E-08193, Bellaterra, Catalonia, Spain
- CREAF, E-08193, Cerdanyola del Vallès, Catalonia, Spain
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Hu W, Zhang H, Chen H, Tang M. Arbuscular mycorrhizas influence Lycium barbarum tolerance of water stress in a hot environment. MYCORRHIZA 2017; 27:451-463. [PMID: 28185001 DOI: 10.1007/s00572-017-0765-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 01/27/2017] [Indexed: 05/08/2023]
Abstract
Arbuscular mycorrhizal (AM) fungi can assist their hosts to cope with water stress and other abiotic stresses in different ways. In order to test whether AM plants have a greater capacity than control plants to cope with water stress, we investigated the water status and photosynthetic capacity of Lycium barbarum colonized or not by the AM fungus Rhizophagus irregularis under three water conditions during a hot summer. Sugar levels and transcriptional responses of both plant and AM fungus aquaporin genes in roots were analyzed. Compared with control plants, AM plants increased transpiration rate and stomatal conductance but decreased leaf relative water content under moderate water stress. Severe water stress, however, did not inhibit the quantum yield of PSII photochemistry in AM plants versus control plants. AM plants had higher expression levels of plasma membrane intrinsic proteins or tonoplast intrinsic proteins and Rir-AQP2 and lower leaf temperature than control plants under dry-hot stress. Additionally, AM plant sugar levels under normal water conditions were similar to those of control plants under moderate water stress, but sugar levels of AM plants especially increased with severe water stress. When these aspects of performance of AM and control plants under different water conditions are compared overall, AM plants displayed an obvious superiority over control plants at coping with moderate water stress in the hot environment; AM plants maintained normal photochemical processes under severe water stress, while sugar levels were affected strongly.
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Affiliation(s)
- Wentao Hu
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Haoqiang Zhang
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Hui Chen
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Ming Tang
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
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