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Tang W, Liu S, Jing M, Healey JR, Smith MN, Farooq TH, Zhu L, Zhao S, Wu Y. Vegetation growth responses to climate change: A cross-scale analysis of biological memory and time lags using tree ring and satellite data. GLOBAL CHANGE BIOLOGY 2024; 30:e17441. [PMID: 39054867 DOI: 10.1111/gcb.17441] [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: 02/10/2024] [Revised: 06/02/2024] [Accepted: 06/12/2024] [Indexed: 07/27/2024]
Abstract
Vegetation growth is affected by past growth rates and climate variability. However, the impacts of vegetation growth carryover (VGC; biotic) and lagged climatic effects (LCE; abiotic) on tree stem radial growth may be decoupled from photosynthetic capacity, as higher photosynthesis does not always translate into greater growth. To assess the interaction of tree-species level VGC and LCE with ecosystem-scale photosynthetic processes, we utilized tree-ring width (TRW) data for three tree species: Castanopsis eyrei (CE), Castanea henryi (CH, Chinese chinquapin), and Liquidambar formosana (LF, Chinese sweet gum), along with satellite-based data on canopy greenness (EVI, enhanced vegetation index), leaf area index (LAI), and gross primary productivity (GPP). We used vector autoregressive models, impulse response functions, and forecast error variance decomposition to analyze the duration, intensity, and drivers of VGC and of LCE response to precipitation, temperature, and sunshine duration. The results showed that at the tree-species level, VGC in TRW was strongest in the first year, with an average 77% reduction in response intensity by the fourth year. VGC and LCE exhibited species-specific patterns; compared to CE and CH (diffuse-porous species), LF (ring-porous species) exhibited stronger VGC but weaker LCE. For photosynthetic capacity at the ecosystem scale (EVI, LAI, and GPP), VGC and LCE occurred within 96 days. Our study demonstrates that VGC effects play a dominant role in vegetation function and productivity, and that vegetation responses to previous growth states are decoupled from climatic variability. Additionally, we discovered the possibility for tree-ring growth to be decoupled from canopy condition. Investigating VGC and LCE of multiple indicators of vegetation growth at multiple scales has the potential to improve the accuracy of terrestrial global change models.
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Affiliation(s)
- Wenxi Tang
- School of Ecology, Hainan University, Haikou, China
- National Engineering Laboratory for Applied Technology of Forestry & Ecology in South China, Central South University of Forestry and Technology (CSUFT), Changsha, China
- College of Life and Environmental Sciences, CSUFT, Changsha, China
- Technology Innovation Center for Ecological Conservation and Restoration in Dongting Lake Basin, Ministry of Natural Resources, Changsha, China
| | - Shuguang Liu
- School of Ecology, Hainan University, Haikou, China
| | - Mengdan Jing
- Department of Earth & Environmental Science, Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, China
| | - John R Healey
- School of Environmental and Natural Sciences, Bangor University, Bangor, Gwynedd, UK
| | - Marielle N Smith
- School of Environmental and Natural Sciences, Bangor University, Bangor, Gwynedd, UK
- Bangor College China, A Joint Unit of Bangor University and Central South University of Forestry and Technology, Changsha, China
| | - Taimoor Hassan Farooq
- Bangor College China, A Joint Unit of Bangor University and Central South University of Forestry and Technology, Changsha, China
| | - Liangjun Zhu
- National Engineering Laboratory for Applied Technology of Forestry & Ecology in South China, Central South University of Forestry and Technology (CSUFT), Changsha, China
- College of Life and Environmental Sciences, CSUFT, Changsha, China
| | - Shuqing Zhao
- School of Ecology, Hainan University, Haikou, China
| | - Yiping Wu
- Department of Earth & Environmental Science, Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, China
- National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain, Xi'an, China
- Technology Innovation Center for Land Engineering and Human Settlements, Shaanxi Land Engineering Construction Group Co. Ltd and Xi'an Jiaotong University, Xi'an, China
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Pernicová N, Urban O, Čáslavský J, Kolář T, Rybníček M, Sochová I, Peñuelas J, Bošeľa M, Trnka M. Impacts of elevated CO 2 levels and temperature on photosynthesis and stomatal closure along an altitudinal gradient are counteracted by the rising atmospheric vapor pressure deficit. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171173. [PMID: 38401718 DOI: 10.1016/j.scitotenv.2024.171173] [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: 12/04/2023] [Revised: 02/09/2024] [Accepted: 02/20/2024] [Indexed: 02/26/2024]
Abstract
The efficiency of water use in plants, a critical ecophysiological parameter closely related to water and carbon cycles, is essential for understanding the interactions between plants and their environment. This study investigates the effects of ongoing climate change and increasing atmospheric CO2 concentration on intrinsic (stomata-based; iWUE) and evaporative (transpiration-based; eWUE) water use efficiency in oak trees along a naturally small altitudinal gradient (130-630 m a.s.l.) of Vihorlat Mountains (eastern Slovakia, Central Europe). To assess changes in iWUE and eWUE values over the past 60 years (1961-2020), stable carbon isotope ratios in latewood cellulose (δ13Ccell) of annually resolved tree rings were analyzed. Such an approach was sensitive enough to distinguish tree responses to growth environments at different altitudes. Our findings revealed a rising trend in iWUE, particularly in oak trees at low and middle altitudes. However, this increase was negligible at high altitudes. Warmer and drier conditions at lower altitudes likely led to significant stomatal closure and enhanced efficiency in photosynthetic CO2 uptake due to rising CO2 concentration. Conversely, the increasing intracellular-to-ambient CO2 ratio (Ci/Ca) at higher altitudes indicated lower efficiency in photosynthetic CO2 uptake. In contrast to iWUE, eWUE showed no increasing trends over the last 60 years. This suggests that the positive impacts of elevated CO2 concentrations and temperature on photosynthesis and stomatal closure are counteracted by the rising atmospheric vapor pressure deficit (VPD). These differences underscore the importance of the correct interpretation of stomata-based and transpiration-based WUEs and highlight the necessity of atmospheric VPD correction when applying tree-ring δ13C-derived WUE at ecosystem and global levels.
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Affiliation(s)
- Natálie Pernicová
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; Mendel University in Brno, Department of Agrosystems and Bioclimatology, Faculty of AgriSciences, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Otmar Urban
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic.
| | - Josef Čáslavský
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic
| | - Tomáš Kolář
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; Mendel University in Brno, Department of Wood Science and Technology, Faculty of Forestry and Wood Technology, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Michal Rybníček
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; Mendel University in Brno, Department of Wood Science and Technology, Faculty of Forestry and Wood Technology, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Irena Sochová
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; Mendel University in Brno, Department of Wood Science and Technology, Faculty of Forestry and Wood Technology, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Josep Peñuelas
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra 08193, Catalonia, Spain; CREAF, Cerdanyola del Vallès 08193, Catalonia, Spain
| | - Michal Bošeľa
- Faculty of Forestry, Technical University in Zvolen, T. G. Masaryka 24, SK-960 01 Zvolen, Slovakia
| | - Miroslav Trnka
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; Mendel University in Brno, Department of Agrosystems and Bioclimatology, Faculty of AgriSciences, Zemědělská 1, CZ-613 00 Brno, Czech Republic
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3
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Ren W, Tian L, Querejeta JI. Tight coupling between leaf δ 13 C and N content along leaf ageing in the N 2 -fixing legume tree black locust (Robinia pseudoacacia L.). PHYSIOLOGIA PLANTARUM 2024; 176:e14235. [PMID: 38472162 DOI: 10.1111/ppl.14235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 01/29/2024] [Accepted: 02/08/2024] [Indexed: 03/14/2024]
Abstract
N2 -fixing legumes can strongly affect ecosystem functions by supplying nitrogen (N) and improving the carbon-fixing capacity of vegetation. Still, the question of how their leaf-level N status and carbon metabolism are coordinated along leaf ageing remains unexplored. Leaf tissue carbon isotopic composition (δ13 C) provides a useful indicator of time-integrated intrinsic water use efficiency (WUEi). Here, we quantified the seasonal changes of leaf δ13 C, N content on a mass and area basis (Nmass , Narea , respectively), Δ18 O (leaf 18 O enrichment above source water, a proxy of time-integrated stomatal conductance) and morphological traits in an emblematic N2 -fixing legume tree, the black locust (Robinia pseudoacacia L.), at a subtropical site in Southwest China. We also measured xylem, soil and rainwater isotopes (δ18 O, δ2 H) to characterize tree water uptake patterns. Xylem water isotopic data reveal that black locust primarily used shallow soil water in this humid habitat. Black locust exhibited a decreasing δ13 C along leaf ageing, which was largely driven by decreasing leaf Nmass , despite roughly constant Narea . In contrast, the decreasing δ13 C along leaf ageing was largely uncoupled from parallel increases in Δ18 O and leaf thickness. Leaf N content is used as a proxy of leaf photosynthetic capacity; thus, it plays a key role in determining the seasonality in δ13 C, whereas the roles of stomatal conductance and leaf morphology are minor. Black locust leaves can effectively adjust to changing environmental conditions along leaf ageing through LMA increases and moderate stomatal conductance reduction while maintaining constant Narea to optimize photosynthesis and carbon assimilation, despite declining leaf Nmass and δ13 C.
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Affiliation(s)
- Wei Ren
- Institute of International Rivers and Eco-Security, Yunnan University, Kunming, China
- Chongqing Key Laboratory of Karst Environment, School of Geographical Sciences, Southwest University, Chongqing, China
| | - Lide Tian
- Institute of International Rivers and Eco-Security, Yunnan University, Kunming, China
- Yunnan Key Laboratory of International Rivers and Transboundary Eco-security, Kunming, China
| | - José Ignacio Querejeta
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS, CSIC), Murcia, Spain
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Huang X, Luo G, Ma Z, Yao B, Du Y, Yang Y. Modeling the effect of grazing on carbon and water use efficiencies in grasslands on the Qinghai-Tibet Plateau. BMC Ecol Evol 2024; 24:26. [PMID: 38408884 PMCID: PMC10898080 DOI: 10.1186/s12862-024-02215-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 02/12/2024] [Indexed: 02/28/2024] Open
Abstract
BACKGROUND Carbon and water use efficiencies (CUE and WUE, respectively) are vital indicators of the adaptability of plants to environmental conditions. However, the effects of grazing and climate change on the spatiotemporal changes in CUE and WUE in Qinghai-Tibet Plateau grasslands (QTPG) are still unclear. RESULTS Using the enhanced Biome-BGCMuSo model in combination with observed data, we estimated and analyzed the spatiotemporal variations in CUE and WUE and their responses to grazing in QTPG from 1979 to 2018. The mean annual CUE was 0.7066 in QTPG from 1979 to 2018 under the actual climate scenario. In general, the grassland CUE was low in the southeast and high in the northwest. Grazing generally decreased CUE in QTPG from 1979 to 2018, and there was an increasing trend in the difference in CUE between the grazing and nongrazing scenarios. The difference in CUE was generally greater in the northwest than in the southeast. The mean annual WUE was 0.5591 g C/kg H2O in QTPG from 1979 to 2018 under the actual climate scenario. After 2000, the grassland WUE exhibited a fluctuating upward trend. In general, the grassland WUE was greater in the southeast than in the northwest. Grazing generally decreased WUE in QTPG from 1979 to 2018, and there was an increasing trend in the difference in WUE between the grazing and nongrazing scenarios. The difference in WUE was generally greater in the northwest than in the southeast. CONCLUSIONS The findings of this study suggested that the spatiotemporal changes in CUE and WUE in QTPG were closely related to changes in the natural environment and grazing management.
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Affiliation(s)
- Xiaotao Huang
- School of Geographical Sciences and Tourism, Zhaotong University, 657000, Zhaotong, Yunnan, China
| | - Geping Luo
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 830011, Urumqi, Xinjiang, China.
| | - Zhen Ma
- Key Laboratory of Restoration Ecology for Cold Regions Laboratory in Qinghai, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, 810008, Xining, Qinghai, China
| | - Buqing Yao
- Key Laboratory of Restoration Ecology for Cold Regions Laboratory in Qinghai, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, 810008, Xining, Qinghai, China.
| | - Yangong Du
- Key Laboratory of Restoration Ecology for Cold Regions Laboratory in Qinghai, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, 810008, Xining, Qinghai, China
| | - Yongsheng Yang
- Key Laboratory of Restoration Ecology for Cold Regions Laboratory in Qinghai, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, 810008, Xining, Qinghai, China
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Chen Z, Wang W, Forzieri G, Cescatti A. Transition from positive to negative indirect CO 2 effects on the vegetation carbon uptake. Nat Commun 2024; 15:1500. [PMID: 38374331 PMCID: PMC10876672 DOI: 10.1038/s41467-024-45957-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 02/08/2024] [Indexed: 02/21/2024] Open
Abstract
Although elevated atmospheric CO2 concentration (eCO2) has substantial indirect effects on vegetation carbon uptake via associated climate change, their dynamics remain unclear. Here we investigate how the impacts of eCO2-driven climate change on growing-season gross primary production have changed globally during 1982-2014, using satellite observations and Earth system models, and evaluate their evolution until the year 2100. We show that the initial positive effect of eCO2-induced climate change on vegetation carbon uptake has declined recently, shifting to negative in the early 21st century. Such emerging pattern appears prominent in high latitudes and occurs in combination with a decrease of direct CO2 physiological effect, ultimately resulting in a sharp reduction of the current growth benefits induced by climate warming and CO2 fertilization. Such weakening of the indirect CO2 effect can be partially attributed to the widespread land drying, and it is expected to be further exacerbated under global warming.
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Affiliation(s)
- Zefeng Chen
- National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing, China
- Yangtze Institute for Conservation and Development, Hohai University, Nanjing, China
- College of Hydrology and Water Resources, Hohai University, Nanjing, China
| | - Weiguang Wang
- National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing, China.
- Yangtze Institute for Conservation and Development, Hohai University, Nanjing, China.
- College of Hydrology and Water Resources, Hohai University, Nanjing, China.
| | - Giovanni Forzieri
- Department of Civil and Environmental Engineering, University of Florence, Florence, Italy
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Li X, Song Z, Hu Y, Qiao J, Chen Y, Wang S, Yue P, Chen M, Ke Y, Xu C, Yu Q, Zuo X. Drought intensity and post-drought precipitation determine vegetation recovery in a desert steppe in Inner Mongolia, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167449. [PMID: 37832659 DOI: 10.1016/j.scitotenv.2023.167449] [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: 09/26/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023]
Abstract
Extreme drought events are expected to increase in frequency and severity, posing significant threats to ecosystems worldwide. While considerable research has been concentrated on the effects of climate extremes on the stability of grasslands, the process by which grassland productivity may recover after extreme drought events are still not well understood. Here, we conducted a four-year (2019-2022) recovery investigation after four-year's (2015-2018) extreme drought treatments of different intensities (control, press and pulse) to explore the vegetation recovery of desert-grassland ecosystems Inner Mongolia, China. Press drought involved a 66 % reduction in natural precipitation from May to August, while pulse drought reduced it by 100 % during June and July. We found that both press and pulse droughts led to a sharp decrease in aboveground net primary productivity (ANPP) after four years, primarily due to reduced growth, density, and productivity of annual and perennial plants. However, ANPP under pulse drought could recover fully after four years of stopping of drought treatment, and it could not under press drought. Additionally, community structure (i.e., species richness, plant density, and height) fully recovered within 1 year after the end of the two extreme drought treatments. Both plant density and height contributed to the ANPP recovery after press and pulse droughts. Structural equation modeling (SEM) results further revealed that the reduction in ANPP during the extreme drought was primarily due to a decrease in plant density caused by reduced soil water content. The recovery of ANPP in pulse drought was directly caused by increased soil water content in the post-extreme drought. These results suggest that drought intensity and precipitation determine ANPP recovery in a degraded desert steppe. Our findings are crucial for deepening understanding of the processes and mechanisms of ecosystem recovery after extreme drought, as well as for the successful management and protection of grassland ecosystems.
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Affiliation(s)
- Xiangyun Li
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Region, Gansu Province, Lanzhou 730000, China
| | - Zhaobin Song
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Region, Gansu Province, Lanzhou 730000, China
| | - Ya Hu
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Region, Gansu Province, Lanzhou 730000, China
| | - Jingjuan Qiao
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Region, Gansu Province, Lanzhou 730000, China
| | - Yuheng Chen
- Ecology and Biodiversity Group, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Shaokun Wang
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Region, Gansu Province, Lanzhou 730000, China
| | - Ping Yue
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Region, Gansu Province, Lanzhou 730000, China
| | - Min Chen
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Region, Gansu Province, Lanzhou 730000, China
| | - Yuguang Ke
- Hulunber Grassland Ecosystem National Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, 100081 Beijing, China
| | - Chong Xu
- Hulunber Grassland Ecosystem National Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, 100081 Beijing, China
| | - Qiang Yu
- School of Grassland Science, Beijing Forestry University, Beijing 10008, China
| | - Xiaoan Zuo
- Urat Desert-grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Region, Gansu Province, Lanzhou 730000, China.
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7
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Gregory LM, Roze LV, Walker BJ. Increased activity of core photorespiratory enzymes and CO 2 transfer conductances are associated with higher and more optimal photosynthetic rates under elevated temperatures in the extremophile Rhazya stricta. PLANT, CELL & ENVIRONMENT 2023; 46:3704-3720. [PMID: 37667571 DOI: 10.1111/pce.14711] [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: 11/11/2022] [Revised: 06/26/2023] [Accepted: 08/23/2023] [Indexed: 09/06/2023]
Abstract
Increase photorespiration and optimising intrinsic water use efficiency are unique challenges to photosynthetic carbon fixation at elevated temperatures. To determine how plants can adapt to facilitate high rates of photorespiration at elevated temperatures while also maintaining water-use efficiency, we performed in-depth gas exchange and biochemical assays of the C3 extremophile, Rhazya stricta. These results demonstrate that R. stricta supports higher rates of photorespiration under elevated temperatures and that these higher rates of photorespiration correlate with increased activity of key photorespiratory enzymes; phosphoglycolate phosphatase and catalase. The increased photorespiratory enzyme activities may increase the overall capacity of photorespiration by reducing enzymatic bottlenecks and allowing minimal inhibitor accumulation under high photorespiratory rates. Additionally, we found the CO2 transfer conductances (stomatal and mesophyll) are re-allocated to increase the water-use efficiency in R. stricta but not necessarily the photosynthetic response to temperature. These results suggest important adaptive strategies in R. stricta that maintain photosynthetic rates under elevated temperatures with optimal water loss. The strategies found in R. stricta may inform breeding and engineering efforts in other C3 species to improve photosynthetic efficiency at high temperatures.
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Affiliation(s)
- Luke M Gregory
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Ludmila V Roze
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
| | - Berkley J Walker
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
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Strange BM, Monson RK, Szejner P, Ehleringer J, Hu J. The North American Monsoon buffers forests against the ongoing megadrought in the Southwestern United States. GLOBAL CHANGE BIOLOGY 2023; 29:4354-4367. [PMID: 37283085 DOI: 10.1111/gcb.16762] [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: 11/09/2022] [Revised: 04/05/2023] [Accepted: 04/08/2023] [Indexed: 06/08/2023]
Abstract
The US Southwest has been entrenched in a two-decade-long megadrought (MD), the most severe since 800 CE, which threatens the long-term vitality and persistence of regional montane forests. Here, we report that in the face of record low winter precipitation and increasing atmospheric aridity, seasonal activity of the North American Monsoon (NAM) climate system brings sufficient precipitation during the height of the summer to alleviate extreme tree water stress. We studied seasonally resolved, tree-ring stable carbon isotope ratios across a 57-year time series (1960-2017) in 17 Ponderosa pine forests distributed across the NAM geographic domain. Our study focused on the isotope dynamics of latewood (LW), which is produced in association with NAM rains. During the MD, populations growing within the core region of the NAM operated at lower intrinsic and higher evaporative water-use efficiencies (WUEi and WUEE , respectively), compared to populations growing in the periphery of the NAM domain, indicating less physiological water stress in those populations with access to NAM moisture. The disparities in water-use efficiencies in periphery populations are due to a higher atmospheric vapor pressure deficit (VPD) and reduced access to summer soil moisture. The buffering advantage of the NAM, however, is weakening. We observed that since the MD, the relationship between WUEi and WUEE in forests within the core NAM domain is shifting toward a drought response similar to forests on the periphery of the NAM. After correcting for past increases in the atmospheric CO2 concentration, we were able to isolate the LW time-series responses to climate alone. This showed that the shift in the relation between WUEi and WUEE was driven by the extreme increases in MD-associated VPD, with little advantageous influence on stomatal conductance from increases in atmospheric CO2 concentration.
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Affiliation(s)
- Brandon M Strange
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, USA
- Laboratory of Tree Ring Research, University of Arizona, Tucson, Arizona, USA
| | - Russell K Monson
- Laboratory of Tree Ring Research, University of Arizona, Tucson, Arizona, USA
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA
| | - Paul Szejner
- Laboratory of Tree Ring Research, University of Arizona, Tucson, Arizona, USA
- Instituto de Geología, Universidad Nacional Autónoma de México, México City, Mexico
| | - Jim Ehleringer
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Jia Hu
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, USA
- Laboratory of Tree Ring Research, University of Arizona, Tucson, Arizona, USA
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9
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Finger-Higgens R, Bishop TBB, Belnap J, Geiger EL, Grote EE, Hoover DL, Reed SC, Duniway MC. Droughting a megadrought: Ecological consequences of a decade of experimental drought atop aridification on the Colorado Plateau. GLOBAL CHANGE BIOLOGY 2023; 29:3364-3377. [PMID: 36919684 DOI: 10.1111/gcb.16681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/20/2023] [Indexed: 05/16/2023]
Abstract
Global dryland vegetation communities will likely change as ongoing drought conditions shift regional climates towards a more arid future. Additional aridification of drylands can impact plant and ground cover, biogeochemical cycles, and plant-soil feedbacks, yet how and when these crucial ecosystem components will respond to drought intensification requires further investigation. Using a long-term precipitation reduction experiment (35% reduction) conducted across the Colorado Plateau and spanning 10 years into a 20+ year regional megadrought, we explored how vegetation cover, soil conditions, and growing season nitrogen (N) availability are impacted by drying climate conditions. We observed large declines for all dominant plant functional types (C3 and C4 grasses and C3 and C4 shrubs) across measurement period, both in the drought treatment and control plots, likely due to ongoing regional megadrought conditions. In experimental drought plots, we observed less plant cover, less biological soil crust cover, warmer and drier soil conditions, and more soil resin-extractable N compared to the control plots. Observed increases in soil N availability were best explained by a negative correlation with plant cover regardless of treatment, suggesting that declines in vegetation N uptake may be driving increases in available soil N. However, in ecosystems experiencing long-term aridification, increased N availability may ultimately result in N losses if soil moisture is consistently too dry to support plant and microbial N immobilization and ecosystem recovery. These results show dramatic, worrisome declines in plant cover with long-term drought. Additionally, this study highlights that more plant cover losses are possible with further drought intensification and underscore that, in addition to large drought effects on aboveground communities, drying trends drive significant changes to critical soil resources such as N availability, all of which could have long-term ecosystem impacts for drylands.
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Affiliation(s)
| | - Tara B B Bishop
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Jayne Belnap
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Erika L Geiger
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Edmund E Grote
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - David L Hoover
- USDA-ARS Rangeland Resource and Systems Research Unit, Crops Research Laboratory, Fort Collins, Colorado, USA
| | - Sasha C Reed
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Michael C Duniway
- US Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
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10
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Hong Y, Liu X, Camarero JJ, Xu G, Zhang L, Zeng X, Aritsara ANA, Zhang Y, Wang W, Xing X, Lu Q. The effects of intrinsic water-use efficiency and climate on wood anatomy. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2023:10.1007/s00484-023-02475-7. [PMID: 37072578 DOI: 10.1007/s00484-023-02475-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
Climate warming may induce growth decline in warm-temperate areas subjected to seasonal soil moisture deficit, whereas increasing atmospheric CO2 concentration (Ca) is expected to enhance tree growth. An accurate understanding of tree growth and physiological processes responding to climate warming and increasing Ca is critical. Here, we analyzed tree-ring stable carbon isotope and wood anatomical traits of Pinus tabuliformis from Qinling Mountains in China to understand how lumen diameter (LD) determining potential hydraulic conductivity and cell-wall thickness (CWT) determining carbon storage responded to climate and Ca. The effects of climate and Ca on intrinsic water-use efficiency (iWUE) were isolated, and iWUE values due to only-climate (iWUEClim) and only-CO2 effects (iWUECO2) were obtained. During a low-iWUE period, the influences of climate on earlywood (EW) LD and latewood (LW) CWT prevailed. During a high-iWUE period, CO2 fertilization promoted cell enlargement and carbon storage but this was counteracted by a negative influence of climate warming. The limiting direct effects of iWUEClim and indirect effects of climate on EW LD were greater than on LW CWT. P. tabuliformis in temperate forests will face a decline of growth and carbon fixation, but will produce embolism-resistant tracheids with narrow lumen responding to future hotter droughts.
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Affiliation(s)
- Yixue Hong
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, 710119, China
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-Sen University, Shenzhen, 518107, 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.
| | - J Julio Camarero
- Instituto Pirenaico de Ecología (IPE-CSIC), Zaragoza, 50092, Spain
| | - Guobao Xu
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Lingnan Zhang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, 710119, China
| | - Xiaomin Zeng
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, 710119, China
| | - Amy Ny Aina Aritsara
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530004, China
| | - Yu Zhang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, 710119, China
| | - Wenzhi Wang
- The Key Laboratory of Mountain Environment Evolution and Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Xiaoyu Xing
- Qinling National Botanical Garden, Xi'an, 710061, China
| | - 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
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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: 1.0] [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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Urrutia-Jalabert R, Barichivich J, Szejner P, Rozas V, Lara A. Ecophysiological responses of Nothofagus obliqua forests to recent climate drying across the Mediterranean-Temperate biome transition in south-central Chile. JOURNAL OF GEOPHYSICAL RESEARCH. BIOGEOSCIENCES 2022; 128:2022jg007293. [PMID: 37484604 PMCID: PMC7614787 DOI: 10.1029/2022jg007293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 03/02/2023] [Indexed: 07/25/2023]
Abstract
The forests of south-central Chile are facing a drying climate and a megadrought that started in 2010. This study addressed the physiological responses of five Nothofagus obliqua stands across the Mediterranean-Temperate gradient (35.9 ° -40.3° S) using carbon isotope discrimination (Δ13 C) and intrinsic water use efficiency (iWUE) in tree rings during 1967-2017. Moreover, δ18O was evaluated in the northernmost site to better understand the effects of the megadrought in this drier location. These forests have become more efficient in their use of water. However, trees from the densest stand are discriminating more against 13C, probably due to reduced photosynthetic rates associated with increasing competition. The strongest associations between climate and Δ13C were found in the northernmost stand, suggesting that warmer and drier conditions could have reduced 13C discrimination. Tree growth in this site has not decreased, and δ18O was negatively related to annual rainfall. However, a shift in this relationship was found since 2007, when both precipitation and δ18O decreased, while correlations between δ18O and growth increased. This implies that tree growth and δ18O are coupled in recent years, but precipitation is not the cause, suggesting that trees probably changed their water source to deeper and more depleted pools. Our research demonstrates that forests are not reducing their growth in central Chile, mainly due to a shift towards the use of deeper water sources. Despite a common climate trend across the gradient, there is a non-uniform response of N. obliqua forests to climate drying, being their response site specific. Keywords: Tree rings, stable isotopes, tree physiology, climate gradient, megadrought, climate change.
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Affiliation(s)
- Rocío Urrutia-Jalabert
- Departamento de Ciencias Naturales y Tecnología, Universidad de Aysén, Coyhaique, Chile
- Laboratorio de Dendrocronología y Cambio Global, Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Valdivia, Chile
- Centro de Ciencia del Clima y la Resiliencia, CR2, Santiago, Chile
| | - Jonathan Barichivich
- Laboratoire des Sciences du Climat et de l'Environnement, IPSL, CRNS/CEA/UVSQ, France
- Instituto de Geografía, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Paul Szejner
- Departamento de Ciencias Ambientales y del suelo, Instituto de Geología, Universidad Nacional Autónoma de México. Ciudad Universitaria CDMX, México
| | - Vicente Rozas
- iuFOR-EiFAB, Área de Botánica, Campus Duques de Soria, Universidad de Valladolid, 42004 Soria, Spain
| | - Antonio Lara
- Laboratorio de Dendrocronología y Cambio Global, Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Valdivia, Chile
- Centro de Ciencia del Clima y la Resiliencia, CR2, Santiago, Chile
- Fundación Centro de los Bosques Nativos FORECOS, Valdivia, Chile
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13
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Fang X, Lin T, Zhang B, Lai Y, Chen X, Xiao Y, Xie Y, Zhu J, Yang Y, Wang J. Regulating carbon and water balance as a strategy to cope with warming and drought climate in Cunninghamia lanceolata in southern China. FRONTIERS IN PLANT SCIENCE 2022; 13:1048930. [PMID: 36466246 PMCID: PMC9714357 DOI: 10.3389/fpls.2022.1048930] [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: 09/20/2022] [Accepted: 10/24/2022] [Indexed: 06/17/2023]
Abstract
Human activities have increased the possibility of simultaneous warming and drought, which will lead to different carbon (C) allocation and water use strategies in plants. However, there is no conclusive information from previous studies. To explore C and water balance strategies of plants in response to warming and drought, we designed a 4-year experiment that included control (CT), warming (W, with a 5°C increase in temperature), drought (D, with a 50% decrease in precipitation), and warming and drought conditions (WD) to investigate the non-structural carbohydrate (NSC), C and nitrogen (N) stoichiometry, and intrinsic water use efficiency (iWUE) of leaves, roots, and litter of Cunninghamia lanceolata, a major tree species in southern China. We found that W significantly increased NSC and starch in the leaves, and increased NSC and soluble sugar is one of the components of NSC in the roots. D significantly increased leaves' NSC and starch, and increased litter soluble sugar. The NSC of the WD did not change significantly, but the soluble sugar was significantly reduced. The iWUE of leaves increased under D, and surprisingly, W and D significantly increased the iWUE of litter. The iWUE was positively correlated with NSC and soluble sugar. In addition, D significantly increased N at the roots and litter, resulting in a significant decrease in the C/N ratio. The principal component analysis showed that NSC, iWUE, N, and C/N ratio can be used as identifying indicators for C. lanceolata in both warming and drought periods. This study stated that under warming or drought, C. lanceolata would decline in growth to maintain high NSC levels and reduce water loss. Leaves would store starch to improve the resiliency of the aboveground parts, and the roots would increase soluble sugar and N accumulation to conserve water and to help C sequestration in the underground part. At the same time, defoliation was potentially beneficial for maintaining C and water balance. However, when combined with warming and drought, C. lanceolata growth will be limited by C, resulting in decreased NSC. This study provides a new insight into the coping strategies of plants in adapting to warming and drought environments.
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Affiliation(s)
- Xuan Fang
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- School of Life Sciences, Fujian Normal University, Fuzhou, China
- Fujian Sanming Forest Ecosystem National Observation and Research Station, Sanming, China
| | - Tian Lin
- School of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou, China
| | - Biyao Zhang
- School of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Yongru Lai
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- School of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Xupeng Chen
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- School of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Yixin Xiao
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- School of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Yiqing Xie
- Institute of Economic Forestry, Fujian Academy of Forestry, Fuzhou, China
| | - Jinmao Zhu
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- School of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Yusheng Yang
- Fujian Sanming Forest Ecosystem National Observation and Research Station, Sanming, China
- State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, Fujian Normal University, Fuzhou, China
- School of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Jian Wang
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fujian Normal University, Fuzhou, China
- Fujian Sanming Forest Ecosystem National Observation and Research Station, Sanming, China
- School of Geographical Sciences, Fujian Normal University, Fuzhou, China
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14
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Ehleringer JR, Driscoll AW. Intrinsic water-use efficiency influences establishment in Encelia farinosa. Oecologia 2022; 199:563-578. [PMID: 35819533 DOI: 10.1007/s00442-022-05217-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 06/21/2022] [Indexed: 11/25/2022]
Abstract
We describe establishment of Encelia farinosa, a drought-deciduous shrub common to the Mojave and Sonoran Deserts, based on annual observations of two populations between 1980 and 2020. Only 11 establishment events of 50 + yearlings (0.02-0.03 individuals m-2) occurred during this monitoring period; in 68% of the years fewer than 10 yearlings were established. Yearling survival to adulthood (age 4) ranged from 88 to 5% and was significantly related to cumulative precipitation. Juvenile survival rates were lowest during the current megadrought period. We calculated intrinsic water-use efficiency (iWUE) and observed the widest variations in iWUE values among the youngest plants. Among juveniles, surviving yearlings with the lowest iWUE values exhibited upward ontogenetic shifts in iWUE values, whereas those yearlings with the highest initial iWUE values exhibited little if any change. Juvenile size, higher iWUE values, and greater likelihood of surviving were all positively related with each other over the past several decades. Furthermore, iWUE and photosynthetic capacity were positively related to each other, providing a mechanistic explanation for why increased iWUE values among juveniles could lead to greater survival rates and to larger plants under water-deficit conditions. We posit that there is bi-directional selection for genotypic variations in iWUE values among E. farinosa and that this variation is selected for because of interannual environmental heterogeneity in precipitation and VPD associated with both high- and low-frequency climate cycles. Extreme drought cycles may favor plants with higher iWUE values, whereas more mesic periods may allow for greater persistence of lower iWUE genotypes.
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Affiliation(s)
- James R Ehleringer
- School of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT, 84112, USA.
| | - Avery W Driscoll
- School of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT, 84112, USA
- Present Address: Department of Soil and Crop Sciences, Colorado State University, 301 University Avenue, Fort Collins, CO, 80523, USA
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15
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Strongly Active Responses of Pinus tabuliformis Carr. and Sophora viciifolia Hance to CO2 Enrichment and Drought Revealed by Tree-Ring Isotopes on the Central China Loess Plateau. FORESTS 2022. [DOI: 10.3390/f13070986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Understanding the water-use strategy of human-planted species used in response to climate change is essential to optimize afforestation programs in dry regions. Since 2000, trees on the central Loess Plateau have experienced a shift from strengthening drought to weakening drought. In this study, we combined tree-ring δ13C and δ18O records from Pinus tabuliformis (syn. tabulaeformis) Carr. (a tree) and Sophora viciifolia Hance (a shrub) on the central Loess Plateau to investigate species-specific responses to rising atmospheric CO2 (Ca) and drought. We found summer relative humidity controlled the fractionation of tree-ring δ18O, but the magnitude of the climate influence on δ13C differed between the species. The intrinsic water-use efficiency (iWUE) trends of both species suggested a strongly active response to maintain constant intercellular CO2 concentrations as Ca rose. The tree-ring δ13C and δ18O of both species using first-difference data were significantly and positively correlated, with stronger relationships for the shrub. This indicated the dominant regulation of iWUE by stomatal conductance in both species, but with greater stomatal control for the shrub. Moreover, the higher mean iWUE value of S. viciifolia indicated a more conservative water-use strategy than P. tabuliformis. Based on our commonality analysis, the main driver of the increased iWUE was the joint effect of Ca and vapor-pressure deficit (25.51%) for the tree, while it was the joint effect of Ca and the self-calibrated Palmer drought severity index (39.13%) for the shrub. These results suggest S. viciifolia will be more drought-tolerant than P. tabuliformis and as Ca continually rises, we should focus more on the effects of soil drought than atmospheric drought on the water-use strategy of S. viciifolia.
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16
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Chi CJE, Zinsmeister D, Lai IL, Chang SC, Kuo YL, Burkhardt J. Aerosol Impacts on Water Relations of Camphor ( Cinnamomum camphora). FRONTIERS IN PLANT SCIENCE 2022; 13:892096. [PMID: 35795349 PMCID: PMC9251497 DOI: 10.3389/fpls.2022.892096] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Major parts of anthropogenic and natural aerosols are hygroscopic and deliquesce at high humidity, particularly when depositing to leaf surfaces close to transpiring stomata. Deliquescence and subsequent salt creep may establish thin, extraordinary pathways into the stomata, which foster stomatal uptake of nutrients and water but may also cause stomatal liquid water loss by wicking. Such additional water loss is not accompanied by a wider stomatal aperture with a larger CO2 influx and hypothetically reduces water use efficiency (WUE). Here, the possible direct impacts of aerosols on physical and physiological parameters of camphor (Cinnamomum camphora) were studied (i) in a greenhouse experiment using aerosol exclusion and (ii) in a field study in Taiwan, comparing trees at two sites with different aerosol regimes. Scanning electron microscopy (SEM) images showed that leaves grown under aerosol exclusion in filtered air (FA) were lacking the amorphous, flat areas that were abundant on leaves grown in ambient air (AA), suggesting salt crusts formed from deliquescent aerosols. Increasing vapor pressure deficit (VPD) resulted in half the Ball-Berry slope and double WUE for AA compared to FA leaves. This apparent contradiction to the wicking hypothesis may be due to the independent, overcompensating effect of stomatal closure in response to VPD, which affects AA more than FA stomata. Compared to leaves in a more polluted region in the Taiwanese Southwest, NaCl aerosols dominated the leaf surface conditions on mature camphor trees in Eastern Taiwan, while the considerably lower contact angles and the 2.5 times higher minimum epidermal conductances might have come from organic surfactants. Interpretations of SEM images from leaf surface microstructures should consider amorphous areas as possible indicators of aerosol deposition and other hygroscopic material. The amount and type of the material determine the resulting impacts on plant water relations, together with the surrounding atmosphere and ecophysiological traits.
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Affiliation(s)
- Chia-Ju Ellen Chi
- Institute of Crop Science and Resource Conservation, University of Bonn, Bonn, Germany
| | - Daniel Zinsmeister
- Institute of Crop Science and Resource Conservation, University of Bonn, Bonn, Germany
| | - I-Ling Lai
- Graduate Institute of Bioresources, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Shih-Chieh Chang
- Department of Natural Resources and Environmental Studies, Center for Interdisciplinary Research on Ecology and Sustainability, National Dong Hwa University, Hualien, Taiwan
| | - Yau-Lun Kuo
- Department of Forestry, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Jürgen Burkhardt
- Institute of Crop Science and Resource Conservation, University of Bonn, Bonn, Germany
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17
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Tree growth sensitivity to climate varies across a seasonal precipitation gradient. Oecologia 2022; 198:933-946. [DOI: 10.1007/s00442-022-05156-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 03/28/2022] [Indexed: 10/18/2022]
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