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Finocchiaro M, Médail F, Saatkamp A, Diadema K, Pavon D, Brousset L, Meineri E. Microrefugia and microclimate: Unraveling decoupling potential and resistance to heatwaves. Sci Total Environ 2024; 924:171696. [PMID: 38485012 DOI: 10.1016/j.scitotenv.2024.171696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 03/11/2024] [Accepted: 03/11/2024] [Indexed: 03/19/2024]
Abstract
Microrefugia, defined as small areas maintaining populations of species outside their range margins during environmental extremes, are increasingly recognized for their role in conserving species in the face of climate change. Understanding their microclimatic dynamics becomes crucial with global warming leading to severe temperature and precipitation changes. This study investigates the phenomenon of short-term climatic decoupling within microrefugia and its implications for plant persistence in the Mediterranean region of southeastern France. We focus on microrefugia's ability to climatically disconnect from macroclimatic trends, examining temperature and Vapor Pressure Deficit (VPD) dynamics in microrefugia, adjacent control plots, and weather stations. Our study encompasses both "normal" conditions and heatwave episodes to explore the role of microrefugia as thermal and moisture insulators during extreme events. Landscape attributes such as relative elevation, solar radiation, distance to streams, and vegetation height are investigated for their contribution to short-term decoupling. Our results demonstrate that microrefugia exhibit notable decoupling from macroclimatic trends. This effect is maintained during heatwaves, underscoring microrefugia's vital role in responding to climatic extremes. Importantly, microrefugia maintain lower VPD levels than their surroundings outside and during heatwaves, potentially mitigating water stress for plants. This study advances our understanding of microclimate dynamics within microrefugia and underscores their ecological importance for plant persistence in a changing climate. As heatwaves become more frequent and severe, our findings provide insights into the role of microrefugia in buffering but also decoupling against extreme climatic events and, more generally, against climate warming. This knowledge emphasizes the need to detect and protect existing microrefugia, as they can be integrated into conservation strategies and climate change adaptation plans.
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Affiliation(s)
- Marie Finocchiaro
- Aix Marseille Université, Université Avignon, CNRS, IRD, UMR IMBE, Marseille, France.
| | - Frédéric Médail
- Aix Marseille Université, Université Avignon, CNRS, IRD, UMR IMBE, Marseille, France
| | - Arne Saatkamp
- Aix Marseille Université, Université Avignon, CNRS, IRD, UMR IMBE, Marseille, France
| | - Katia Diadema
- Conservatoire botanique national méditerranéen, 34 avenue Gambetta, F-83400 Hyères, France
| | - Daniel Pavon
- Aix Marseille Université, Université Avignon, CNRS, IRD, UMR IMBE, Marseille, France
| | - Lenka Brousset
- Aix Marseille Université, Université Avignon, CNRS, IRD, UMR IMBE, Marseille, France
| | - Eric Meineri
- Aix Marseille Université, Université Avignon, CNRS, IRD, UMR IMBE, Marseille, France
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Shekhar A, Hörtnagl L, Paul-Limoges E, Etzold S, Zweifel R, Buchmann N, Gharun M. Contrasting impact of extreme soil and atmospheric dryness on the functioning of trees and forests. Sci Total Environ 2024; 916:169931. [PMID: 38199368 DOI: 10.1016/j.scitotenv.2024.169931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 01/12/2024]
Abstract
Recent studies indicate an increase in the frequency of extreme compound dryness days (days with both extreme soil AND air dryness) across central Europe in the future, with little information on their impact on the functioning of trees and forests. This study aims to quantify and assess the impact of extreme soil dryness, extreme air dryness, and extreme compound dryness on the functioning of trees and forests. For this, >15 years of ecosystem-level (carbon dioxide and water vapor fluxes) and 6-10 years of tree-level measurements (transpiration and growth) each from a montane mixed deciduous forest (CH-Lae) and a subalpine evergreen coniferous forest (CH-Dav) in Switzerland, is used. The results showed extreme air dryness limitation on CO2 fluxes and extreme soil dryness limitations on water vapor fluxes. Additionally, CH-Dav was mainly affected by extreme air dryness whereas CH-Lae was affected by both extreme soil dryness and extreme air dryness. The impact of extreme compound dryness on net CO2 uptake (about 75 % decrease) was more due to higher increased ecosystem respiration (40 % and 70 % increase at CH-Dav and CH-Lae, respectively) than decreased gross primary productivity (10 % and 40 % decrease at CH-Dav and CH-Lae, respectively). A significant negative impact on evapotranspiration and transpiration was only observed at CH-Lae during extreme soil and compound dryness (about 25 % decrease). Furthermore, with some differences, the tree-level impact on tree water deficit, transpiration, and growth were consistent with the ecosystem-level impact on carbon uptake and evapotranspiration. Finally, the impact of extreme dryness showed no significant relationship with tree allometry (diameter and height) but across different tree species. The projected future is likely to expose these forest areas to more extreme and frequent dryness conditions, thus compromising the functioning of trees and forests, thereby calling for management interventions to increase the adaptive capacity and resistance of these forests.
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Affiliation(s)
- Ankit Shekhar
- Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland.
| | - Lukas Hörtnagl
- Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
| | - Eugénie Paul-Limoges
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Sophia Etzold
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Roman Zweifel
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Nina Buchmann
- Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
| | - Mana Gharun
- Faculty of Geosciences, University of Münster, 48149 Münster, Germany
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3
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Gaertner B. Geospatial patterns in runoff projections using random forest based forecasting of time-series data for the mid-Atlantic region of the United States. Sci Total Environ 2024; 912:169211. [PMID: 38097071 DOI: 10.1016/j.scitotenv.2023.169211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 10/24/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023]
Abstract
This research explores the geospatial patterns of historical runoff for the period 1958-2021 in the Mid-Atlantic region and uses these time-series data plus nine external climatic and hydrologic variables to predict future runoff for the period 2022-2031. Gridded, average monthly climatic water balance data were obtained from the TerraClimate dataset. A cluster analysis of the long term (1958-2021) historical runoff found 13 significant temporal trends, which tend to form large contiguous regions associated with climate gradients and topographic patterns. The runoff time-series clusters, and the associated time-series of 9 TerraClimate variables, were used to generate random forest based forecast models to predict future (2022-2031) runoff. The random forest-based forecast with the greatest accuracy included inputs of actual evapotranspiration, climate water deficit, minimum, average, and maximum temperature, and vapor pressure deficit. The final model predicted significantly increasing runoff in nine of the 13 clusters.
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Affiliation(s)
- Brandi Gaertner
- The Pennsylvania State University, 2217 Earth and Engineering Sciences Building, University Park, PA 16802, United States.
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Qiu R, Han G, Li S, Tian F, Ma X, Gong W. Soil moisture dominates the variation of gross primary productivity during hot drought in drylands. Sci Total Environ 2023; 899:165686. [PMID: 37482354 DOI: 10.1016/j.scitotenv.2023.165686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/17/2023] [Accepted: 07/18/2023] [Indexed: 07/25/2023]
Abstract
The frequency and severity of hot drought will increase in the future due to impact of climate change and human activities, threatening the sustainability of terrestrial ecosystems and human societies. Hot drought is a typical type of drought event, high vapor pressure deficit (VPD) and low soil moisture (SM) are its main characteristics of hot drought, with increasing water stress on vegetation and exacerbating hydrological drought and ecosystem risks. However, our understanding of the effects of high VPD and low SM on vegetation productivity is limited, because these two variables are strongly coupled and influenced by other climatic drivers. The southwestern United States experienced one of the most severe hot drought events on record in 2020. In this study, we used SM and gross primary productivity (GPP) datasets from Soil Moisture Active and Passive (SMAP), as well as VPD and other meteorological datasets from gridMET. We decoupled the effects of different meteorological factors on GPP at monthly and daily scales using partial correlation analysis, partial least squares regression, and binning methods. We found that SM anomalies contribute more to GPP anomalies than VPD anomalies at monthly and daily scales. Especially at the daily scale, as the decoupled SM anomalies increased, the GPP anomalies increased. However, there is no significant change in GPP anomalies as VPD increases. For all the vegetation types and arid zones, SM dominated the variation in GPP, followed by VPD or maximum temperature. At the flux tower scale, decoupled soil water content (SWC) also dominated changes in GPP, compared to VPD. In the next century, hot drought will occur frequently in dryland regions, where GPP is one of the highest uncertainties in terrestrial ecosystems. Our study has important implications for identifying the strong coupling of meteorological factors and their impact on vegetation under climate change.
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Affiliation(s)
- Ruonan Qiu
- School of Remote Sensing and Information Engineering, Wuhan University, Wuhan 430079, China
| | - Ge Han
- School of Remote Sensing and Information Engineering, Wuhan University, Wuhan 430079, China; Perception and Effectiveness Assessment for Carbon-neutral Efforts, Engineering Research Center of Ministry of Education, Wuhan, China.
| | - Siwei Li
- School of Remote Sensing and Information Engineering, Wuhan University, Wuhan 430079, China.
| | - Feng Tian
- School of Remote Sensing and Information Engineering, Wuhan University, Wuhan 430079, China
| | - Xin Ma
- State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, China
| | - Wei Gong
- Electronic Information School, Wuhan University, Wuhan 430079, China; Hubei Luojia Laboratory, Wuhan, China
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Weaver SJ, McIntyre T, van Rossum T, Telemeco RS, Taylor EN. Hydration and evaporative water loss of lizards change in response to temperature and humidity acclimation. J Exp Biol 2023; 226:jeb246459. [PMID: 37767755 DOI: 10.1242/jeb.246459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/21/2023] [Indexed: 09/29/2023]
Abstract
Testing acclimation plasticity informs our understanding of organismal physiology and applies to conservation management amidst our rapidly changing climate. Although there is a wealth of research on the plasticity of thermal and hydric physiology in response to temperature acclimation, there is a comparative gap for research on acclimation to different hydric regimes, as well as the interaction between water and temperature. We sought to fill this gap by acclimating western fence lizards (Sceloporus occidentalis) to experimental climate conditions (crossed design of hot or cool, dry or humid) for 8 days, and measuring cutaneous evaporative water loss (CEWL), plasma osmolality, hematocrit and body mass before and after acclimation. CEWL changed plastically in response to the different climates, with lizards acclimated to hot humid conditions experiencing the greatest increase in CEWL. Change in CEWL among individuals was negatively related to treatment vapor pressure deficit and positively related to treatment water vapor pressure. Plasma osmolality, hematocrit and body mass all showed greater changes in response to temperature than to humidity or vapor pressure deficit. CEWL and plasma osmolality were positively related across treatment groups before acclimation and within treatment groups after acclimation, but the two variables showed different responses to acclimation, suggesting that they are interrelated but governed by different mechanisms. This study is among few that assess more than one metric of hydric physiology and that test the interactive effects of temperature and humidity. Such measurements will be essential for predictive models of activity and survival for animals under climate change.
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Affiliation(s)
- Savannah J Weaver
- Biological Sciences Department, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, CA 93407-0401, USA
| | - Tess McIntyre
- Biological Sciences Department, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, CA 93407-0401, USA
| | - Taylor van Rossum
- Biological Sciences Department, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, CA 93407-0401, USA
| | - Rory S Telemeco
- Department of Conservation Science, Fresno Chaffee Zoo, Fresno, CA 93728, USA
- Department of Biology, College of Science and Mathematics, California State University, Fresno, CA 93740, USA
| | - Emily N Taylor
- Biological Sciences Department, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, CA 93407-0401, USA
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He P, Han Z, He M, Meng X, Ma X, Liu H, Dong T, Shi M, Sun Z. Atmospheric dryness thresholds of grassland productivity decline in China. J Environ Manage 2023; 338:117780. [PMID: 36965424 DOI: 10.1016/j.jenvman.2023.117780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 03/13/2023] [Accepted: 03/19/2023] [Indexed: 06/18/2023]
Abstract
Atmospheric dryness events are bound to have a broad and profound impact on the functions and structures of grassland ecosystems. Current research has confirmed that atmospheric dryness is a key moisture constraint that inhibits grassland productivity, yet the risk threshold for atmospheric dryness to initiate ecosystem productivity loss has not been explored. Based on this, we used four terrestrial ecosystem models to simulate gross primary productivity (GPP) data, analyzed the role of vapor pressure deficit (VPD) in regulating interannual variability in Chinese grasslands by focusing on the dependence structure of VPD and GPP, and then constructed a bivariate linkage function to calculate the conditional probability of ecosystem GPP loss under atmospheric dryness, and further analyzed the risk threshold of ecosystem GPP loss triggered by atmospheric dryness. The main results are as follows: we found that (1) the observed and modeled VPD of Chinese grasslands increases rapidly in both historical and future periods. VPD has a strongly negative regulation on ecosystem GPP, and atmospheric dryness is an important moisture constraint that causes deficit and even death to ecosystem GPP. (2) The probability of the enhanced atmospheric dryness that induced GPP decline in Chinese grasslands in the future period increases significantly. (3) When the VPD is higher than 40.07 and 27.65 percentile of the past and future time series, respectively, the risk threshold of slight ecosystem GPP loss can be easily initiated by atmospheric dryness. (4) When the VPD is higher than 82.57 and 65.09 percentile, respectively, the threshold of moderate ecosystem GPP loss can be exceeded by the benchmark probability. (5) The risk threshold of severe ecosystem GPP loss is not initiated by atmospheric dryness in the historical period, and the threshold of severe ecosystem GPP loss can be initiated when the future VPD is higher than 91.92 percentile. In total, a slight atmospheric dryness event is required to initiate a slight ecosystem GPP loss threshold, and a stronger atmospheric dryness event is required to initiate a severe ecosystem GPP loss. Our study enhances the understandings of past and future atmospheric dryness on grassland ecosystems, and strongly suggests that more attention be invested in improving next-generation models of vegetation dynamics processes with respect to the response of mechanisms of ecosystem to atmospheric dryness.
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Affiliation(s)
- Panxing He
- Henan Normal University, Xinxiang, 453007, China; Ministry of Education Key Laboratory for Western Arid Region Grassland Resources and Ecology, Xinjiang Agricultural University, Urumqi, 830000, China.
| | - Zhiming Han
- College of Resources and Environment, Northwest A&F University, Yangling, 712100, China
| | - Mingzhu He
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730020, China
| | - Xiaoyu Meng
- Key Research Institute of Yellow River Civilization and Sustainable, Development Collaborative Innovation Center on Yellow River Civilization, Henan University, Kaifeng, 475000, China.
| | - Xiaoliang Ma
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China
| | - Huixia Liu
- Ministry of Education Key Laboratory for Western Arid Region Grassland Resources and Ecology, Xinjiang Agricultural University, Urumqi, 830000, China
| | - Tong Dong
- Ministry of Education Key Laboratory for Western Arid Region Grassland Resources and Ecology, Xinjiang Agricultural University, Urumqi, 830000, China
| | - Mingjie Shi
- Ministry of Education Key Laboratory for Western Arid Region Grassland Resources and Ecology, Xinjiang Agricultural University, Urumqi, 830000, China
| | - Zongjiu Sun
- Ministry of Education Key Laboratory for Western Arid Region Grassland Resources and Ecology, Xinjiang Agricultural University, Urumqi, 830000, China.
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7
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Zheng J, Sun N, Yan J, Liu C, Yin S. Decoupling between carbon source and sink induced by responses of daily stem growth to water availability in subtropical urban forests. Sci Total Environ 2023; 877:162802. [PMID: 36924954 DOI: 10.1016/j.scitotenv.2023.162802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/21/2023] [Accepted: 03/07/2023] [Indexed: 05/06/2023]
Abstract
Urban forests are anticipated to offer sustainable ecosystem services, necessitating a comprehensive understanding of the ways in which trees respond to environmental changes. This study monitored stem radius fluctuations in Cinnamomum camphora and Taxodium distichum var. imbricatum trees using high-resolution dendrometers at two sites, respectively. Gross primary production (GPP) was measured using eddy-covariance techniques and aggregated to daily sums. Hourly and daily stem radius fluctuations were estimated across both species, and the responses of stems to radiation (Rg), air temperature (Tair), vapor pressure deficit (VPD), and soil humidity (SoilH) were quantified using Bayesian linear models. The diel growth patterns of the monitored trees showed similar characteristics at the species level. Results revealed that trees growth occurred primarily at night, with the lowest hourly contribution to total growth and probability for growth occurring in the afternoon. Furthermore, the Bayesian models indicated that VPD was the most important driver of daily growth and growth probability. After considering the potential constraints imposed by VPD, a modified Gompertz equation showed good performance, with R2 ranging from 0.94 to 0.99 for the relationship between accumulative growth and time. Bayes-based model-independent data assimilation using advanced Markov chain Monte Carlo (MCMC) algorithms provided deeper insights into nonlinear model parameterization. Finally, the quantified relationship between GPP and stem daily growth revealed that the decoupling between carbon source and sink increased with VPD. These findings provided direct empirical evidence for VPD as a key driver of daily growth patterns and raise questions about carbon neutrality accounting under future climate change given the uncertainties induced by increased water stress limitations on carbon utilization.
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Affiliation(s)
- Ji Zheng
- School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China
| | - Ningxiao Sun
- School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China; Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai 200240, China; Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai 200240, China
| | - Jingli Yan
- School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China; Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai 200240, China; Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai 200240, China
| | - Chunjiang Liu
- School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China; Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai 200240, China; Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai 200240, China
| | - Shan Yin
- School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China; Shanghai Urban Forest Ecosystem Research Station, National Forestry and Grassland Administration, Shanghai 200240, China; Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Ministry of Education, Shanghai 200240, China; Key Laboratory for Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai 200240, China.
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Du J, Dai X, Huo Z, Wang X, Wang S, Wang C, Zhang C, Huang G. Stand transpiration and canopy conductance dynamics of Populus popularis under varying water availability in an arid area. Sci Total Environ 2023:164397. [PMID: 37247732 DOI: 10.1016/j.scitotenv.2023.164397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/07/2023] [Accepted: 05/20/2023] [Indexed: 05/31/2023]
Abstract
As a tree species of shelterbelts, Populus popularis maintains significant ecological functions in arid and semiarid areas. However, stand transpiration (T) and canopy conductance (gc) dynamics of P. popularis are unclear in arid irrigated areas with shallow groundwater fluctuations. To better understand the responses of T and gc to meteorological factors, soil water, and shallow groundwater in arid areas, we observed the environmental conditions and sap flow of P. popularis, and quantified T and gc in three growing seasons of 2018-2020 in a typical arid area of China. Results showed T and gc ranged from 0.18 to 6.11 mm day-1 and 2.26-12.54 mm s-1 in 2018-2020, respectively. Solar radiation and vapor pressure deficit (VPD) were major drivers of T at daily scales. It was consistently found that T exponentially decreased with increasing groundwater table depth (GTD) and decreasing reference evapotranspiration in three years. gc is primarily influenced by VPD and is positively related to soil water content in 0-30 cm soil layer (SWC0-30 cm). Moreover, low SWC0-30 cm and deepening GTD jointly decreased T and gc by 22.45 % and 30.41 %, respectively. The response of gc to VPD was susceptible to groundwater fluctuations, and the synergistic influences of VPD and GTD on gc could be well described by the logarithmic function, especially in 2019. The sensitivity of gc to VPD and its variations under different environmental conditions suggested that a flexible stomatal regulation of transpiration occurred in the observed P. popularis with the arid climate and shallow groundwater. These findings provided the essential basis for the water use strategy of P. popularis and stand water resources management in arid regions.
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Affiliation(s)
- Jiali Du
- Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China
| | - Xiaoqin Dai
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
| | - Zailin Huo
- Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China.
| | - Xingwang Wang
- Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China
| | - Shuai Wang
- Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China
| | - Chaozi Wang
- Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China
| | - Chenglong Zhang
- Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China
| | - Guanhua Huang
- Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China
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Su Y, Wang X, Gong C, Chen L, Cui B, Huang B, Wang X. Advances in spring leaf phenology are mainly triggered by elevated temperature along the rural-urban gradient in Beijing, China. Int J Biometeorol 2023; 67:777-791. [PMID: 36943496 DOI: 10.1007/s00484-023-02454-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 02/13/2023] [Accepted: 03/09/2023] [Indexed: 05/25/2023]
Abstract
Urbanization-induced phenological changes have received considerable attention owing to their implications for determining urban ecosystem productivity and predicting the response of plants and ecosystem carbon cycles to future climate change. However, inconsistent rural-urban gradients in plant phenology remain, and phenological drivers other than temperature are poorly understood. In this study, we simultaneously observed the micro-climate and spring leaf phenology of seven woody plant species at 13 parks along a rural-urban gradient in Beijing, China. The minimum (Tmin) and mean (Tmean) air temperature and the minimum (VPDmin) and mean (VPDmean) vapor pressure deficit increased significantly along the rural-urban gradient, but the maximum air temperature (Tmax) and maximum vapor pressure deficit (VPDmax) did not. All observed leaf phenological phases for the seven species were significantly advanced along the rural-urban gradient by 0.20 to 1.02 days/km. Advances in the occurrence of leaf phenological events were significantly correlated with increases in Tmean (accounting for 57-59% variation), Tmin (21-26%), VPDmin (12-16%), and VPDmean (3-5%), but not with changes in Tmax or VPDmax. Advances in spring leaf phenology along the rural-urban gradient differed between non-native species and native species and between shrubs and trees. The reason may be mainly that the sensitivities of spring leaf phenology to micro-climate differ with species origin and growth form. This study highlights that urbanization-induced increases in Tmean and Tmin are the major contributors to advances in spring leaf phenology along the rural-urban gradient, exerting less influence on native species than on non-native species.
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Affiliation(s)
- Yuebo Su
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, People's Republic of China
- Shenzhen Academy of Environmental Sciences, Shenzhen, 518001, China
| | - Xuming Wang
- State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, College of Geographical Science, Fujian Normal University, Fuzhou, 350007, China
| | - Cheng Gong
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Li Chen
- Torch High Technology Industry Development Center, Ministry of Science & Technology, Beijing, 100045, China
| | - Bowen Cui
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Binbin Huang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaoke Wang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, People's Republic of China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Xi X, Yuan X. Remote sensing of atmospheric and soil water stress on ecosystem carbon and water use during flash droughts over eastern China. Sci Total Environ 2023; 868:161715. [PMID: 36682554 DOI: 10.1016/j.scitotenv.2023.161715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/29/2022] [Accepted: 01/15/2023] [Indexed: 06/17/2023]
Abstract
Flash droughts are often accompanied by large soil and atmospheric moisture deficits, and the concurrence of flash droughts and high temperature may have a great impact on the ecosystem. However, the stress of soil and atmospheric moisture deficits on carbon and water use of the ecosystem during flash droughts, especially during the drought periods with hot conditions, are unclear over a large region. In this study, we decoupled the atmospheric and soil water stress over eastern China by using vegetation productivity data and photosynthetically active radiation data retrieved from the Moderate Resolution Imaging Spectroradiometer (MODIS). The analysis is conducted during flash droughts and their sub-periods that are accompanied by high temperature and intense radiation from 2003 to 2018. The results showed that soil moisture (SM) stress was significantly greater than the vapor pressure deficit (VPD) stress on vegetation productivity in the humid regions of eastern China during flash droughts. However, high VPD controlled the water stress on light use efficiency (LUE) of vegetation over 55 % of the regions. For the hot periods of flash droughts, the area subjected to VPD stress on vegetation productivity significantly increased in semi-arid and semi-humid regions. The concurrent hot and drought conditions also increased water use efficiency (WUE) for most areas, which suggests that the reduction percentage of vegetation productivity is larger than that of evapotranspiration. Our research emphasized the severe impact of compound hot and flash drought conditions on vegetation carbon and water use from a remote sensing perspective.
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Affiliation(s)
- Xiazhen Xi
- Key Laboratory of Hydrometeorological Disaster Mechanism and Warning of Ministry of Water Resources/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China; School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing 210044, Jiangsu, China
| | - Xing Yuan
- Key Laboratory of Hydrometeorological Disaster Mechanism and Warning of Ministry of Water Resources/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China; School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing 210044, Jiangsu, China.
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11
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Niu X, Chen Z, Pang Y, Liu X, Liu S. Soil moisture shapes the environmental control mechanism on canopy conductance in a natural oak forest. Sci Total Environ 2023; 857:159363. [PMID: 36240914 DOI: 10.1016/j.scitotenv.2022.159363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/04/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Canopy conductance (gc) is an important biophysical parameter closely related to ecosystem energy partitioning and carbon sequestration, which can be used to judge drought effect on forest ecosystems. It is very important to explore how soil moisture change affects the environmental control mechanism of gc, especially in natural oak forests in Central China where frequent extreme precipitation (P) and drought will occur in a context of climate change. In this study, variations of gc and its environmental control mechanisms in a warm-temperate forest over three consecutive years under different hydroclimatic conditions were examined by using eddy-covariance technique. Results showed that the averaged gc in the three growing seasons were 11.2, 11.3 and 7.8 mms-1, respectively, with a CV of 19.7 %. The lowest gc occurred in the year with the lowest P. Using three years of data, we found that vapor pressure deficit (VPD) exhibited the dominate effect on gc, both diffuse photosynthetically active radiation (PARdif) and air temperature (Ta) were positively correlated with gc. When relative extractable water content (REW) was larger than 0.4, however, inhibiting effect of high VPD on gc disappeared and the effect of direct photosynthetically active radiation (PARdir) on gc was larger compared to PARdif. When REW was <0.1, the positive relationship between Ta and gc became negative. Our results indicated that soil moisture ultimately shapes the environmental control mechanism of gc in a natural oak forest.
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Affiliation(s)
- Xiaodong Niu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing 100091, China; Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, China
| | - Zhicheng Chen
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing 100091, China
| | - Yong Pang
- Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, China
| | - Xiaojing Liu
- Baotianman National Nature Reserve Administrative Bureau, Nanyang 474350, Henan, China
| | - Shirong Liu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing 100091, China.
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12
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Amitrano C, Junker A, D'Agostino N, De Pascale S, De Micco V. Integration of high-throughput phenotyping with anatomical traits of leaves to help understanding lettuce acclimation to a changing environment. Planta 2022; 256:68. [PMID: 36053378 PMCID: PMC9439985 DOI: 10.1007/s00425-022-03984-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 08/25/2022] [Indexed: 06/15/2023]
Abstract
MAIN CONCLUSION The combination of image-based phenotyping with in-depth anatomical analysis allows for a thorough investigation of plant physiological plasticity in acclimation, which is driven by environmental conditions and mediated by anatomical traits. Understanding the ability of plants to respond to fluctuations in environmental conditions is critical to addressing climate change and unlocking the agricultural potential of crops both indoor and in the field. Recent studies have revealed that the degree of eco-physiological acclimation depends on leaf anatomical traits, which show stress-induced alterations during organogenesis. Indeed, it is still a matter of debate whether plant anatomy is the bottleneck for optimal plant physiology or vice versa. Here, we cultivated 'Salanova' lettuces in a phenotyping chamber under two different vapor pressure deficits (VPDs; low, high) and watering levels (well-watered, low-watered); then, plants underwent short-term changes in VPD. We aimed to combine high-throughput phenotyping with leaf anatomical analysis to evaluate their capability in detecting the early stress signals in lettuces and to highlight the different degrees of plants' eco-physiological acclimation to the change in VPD, as influenced by anatomical traits. The results demonstrate that well-watered plants under low VPD developed a morpho-anatomical structure in terms of mesophyll organization, stomatal and vein density, which more efficiently guided the acclimation to sudden changes in environmental conditions and which was not detected by image-based phenotyping alone. Therefore, we emphasized the need to complement high-throughput phenotyping with anatomical trait analysis to unveil crop acclimation mechanisms and predict possible physiological behaviors after sudden environmental fluctuations due to climate changes.
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Affiliation(s)
- Chiara Amitrano
- Department of Agricultural Sciences, University of Naples Federico II, Portici, NA, Italy.
| | - Astrid Junker
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstr. 3, 06466, Seeland, Germany
| | - Nunzio D'Agostino
- Department of Agricultural Sciences, University of Naples Federico II, Portici, NA, Italy
| | - Stefania De Pascale
- Department of Agricultural Sciences, University of Naples Federico II, Portici, NA, Italy
| | - Veronica De Micco
- Department of Agricultural Sciences, University of Naples Federico II, Portici, NA, Italy
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Słowińska S, Słowiński M, Marcisz K, Lamentowicz M. Long-term microclimate study of a peatland in Central Europe to understand microrefugia. Int J Biometeorol 2022; 66:817-832. [PMID: 35113230 PMCID: PMC8948114 DOI: 10.1007/s00484-022-02240-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 11/28/2021] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
Peatlands perform many important ecosystem functions at both the local and global scale, including hydrologic and climatic regulation. Although peatlands often act as climatic microrefugia, they have rarely been the subject of long-term microclimatic studies. In this study, we aimed to compare the local climatic conditions of a mid-forest mire to that of an open area and examine the differences in microclimates within the mire based on plant community diversity, shading, and water table depths. The peatland studied in this work was significantly cooler than the reference site, mainly due to a higher decline in nighttime air temperatures. However, the daily maximum air temperature near the ground was often higher. We also noticed that microclimates significantly differed within the studied peatland. Wet and shaded microsites were cooler than the sites having a lower water level and receiving higher amounts of solar radiation. The results of the study suggest that peatlands have locally cooler climates, and thus can serve as climate change refugia. These findings can help us interpret reconstructed data from the peat archive, and, when combined with experiments, identify tipping points for peatland ecosystems.
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Affiliation(s)
- Sandra Słowińska
- Climate Impacts Laboratory, Department of Geoecology and Climatology, Institute of Geography and Spatial Organization, Polish Academy of Sciences, Warsaw, Poland.
| | - Michał Słowiński
- Past Landscape Dynamics Laboratory, Institute of Geography and Spatial Organization, Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Marcisz
- Climate Change Ecology Research Unit, Faculty of Geographical and Geological Sciences, Adam Mickiewicz University, Poznań, Poland
| | - Mariusz Lamentowicz
- Climate Change Ecology Research Unit, Faculty of Geographical and Geological Sciences, Adam Mickiewicz University, Poznań, Poland
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Resco de Dios V, Cunill Camprubí À, Pérez-Zanón N, Peña JC, Martínez Del Castillo E, Rodrigues M, Yao Y, Yebra M, Vega-García C, Boer MM. Convergence in critical fuel moisture and fire weather thresholds associated with fire activity in the pyroregions of Mediterranean Europe. Sci Total Environ 2022; 806:151462. [PMID: 34742803 DOI: 10.1016/j.scitotenv.2021.151462] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/01/2021] [Accepted: 11/01/2021] [Indexed: 06/13/2023]
Abstract
Wildfires are becoming an increasing threat to many communities worldwide. There has been substantial progress towards understanding the proximal causes of increased fire activity in recent years at regional and national scales. However, subcontinental scale examinations of the commonalities and differences in the drivers of fire activity across different regions are rare in the Mediterranean zone of the European Union (EUMed). Here, we first develop a new classification of EUMed pyroregions, based on grouping different ecoregions with similar seasonal patterns of burned area. We then examine the thresholds associated with fire activity in response to different drivers related to fuel moisture, surface meteorology and atmospheric stability. We document an overarching role for variation in dead fuel moisture content (FMd), or its atmospheric proxy of vapor pressure deficit (VPD), as the major driver of fire activity. A proxy for live fuel moisture content (EVI), wind speed (WS) and the Continuous Haines Index (CH) played secondary, albeit important, roles. There were minor differences in the actual threshold values of FMd (10-12%), EVI (0.29-0.36) and CH (4.9-5.5) associated with the onset of fire activity across pyroregions with peak fire seasons in summer and fall, despite very marked differences in mean annual burned area and fire size range. The average size of fire events increased with the number of drivers exceeding critical thresholds and reaching increasingly extreme values of a driver led to disproportionate increases in the likelihood of a fire becoming a large fire. For instance, the percentage of fires >500 ha increased from 2% to 25% as FMd changed from the wettest to the driest quantile. Our study is among the first to jointly address the roles of fuel moisture, surface meteorology and atmospheric stability on fire activity in EUMed and provides novel insights on the interactions across fire activity triggers.
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Affiliation(s)
- Víctor Resco de Dios
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China; Department of Crop and Forest Sciences, University of Lleida, Lleida, Spain; Joint Research Unit CTFC-AGROTECNIO-CERCA Center, Lleida, Spain.
| | | | | | - Juan Carlos Peña
- Meteorological Service of Catalonia, Barcelona, Spain; Fluvalps-PaleoRisk Research Group, Department of Geography, University of Barcelona, Spain
| | - Edurne Martínez Del Castillo
- Joint Research Unit CTFC-AGROTECNIO-CERCA Center, Lleida, Spain; Department of Geography, Johannes Gutenberg University, 55099 Mainz, Germany
| | - Marcos Rodrigues
- Department of Geography and Land Management, University of Zaragoza, GEOFOREST Group, Spain
| | - Yinan Yao
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China.
| | - Marta Yebra
- Fenner School of Environment & Society, The Australian National University, Canberra, ACT, Australia; Bushfire and Natural Hazards Cooperative Research Centre, Melbourne, VIC, Australia; School of Engineering, The Australian National University, Canberra, ACT, Australia
| | - Cristina Vega-García
- Department of Agricultural and Forest Engineering, University of Lleida, Lleida, Spain; Joint Research Unit CTFC-AGROTECNIO-CERCA Center, Lleida, Spain
| | - Matthias M Boer
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
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Resco de Dios V, Hedo J, Cunill Camprubí À, Thapa P, Martínez Del Castillo E, Martínez de Aragón J, Bonet JA, Balaguer-Romano R, Díaz-Sierra R, Yebra M, Boer MM. Climate change induced declines in fuel moisture may turn currently fire-free Pyrenean mountain forests into fire-prone ecosystems. Sci Total Environ 2021; 797:149104. [PMID: 34303242 DOI: 10.1016/j.scitotenv.2021.149104] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/13/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Fuel moisture limits the availability of fuel to wildfires in many forest areas worldwide, but the effects of climate change on moisture constraints remain largely unknown. Here we addressed how climate affects fuel moisture in pine stands from Catalonia, NE Spain, and the potential effects of increasing climate aridity on burned area in the Pyrenees, a mesic mountainous area where fire is currently rare. We first quantified variation in fuel moisture in six sites distributed across an altitudinal gradient where the long-term mean annual temperature and precipitation vary by 6-15 °C and 395-933 mm, respectively. We observed significant spatial variation in live (78-162%) and dead (10-15%) fuel moisture across sites. The pattern of variation was negatively linked (r = |0.6|-|0.9|) to increases in vapor pressure deficit (VPD) and in the Aridity Index. Using seasonal fire records over 2006-2020, we observed that summer burned area in the Mediterranean forests of Northeast Spain and Southern France was strongly dependent on VPD (r = 0.93), the major driver (and predictor) of dead fuel moisture content (DFMC) at our sites. Based on the difference between VPD thresholds associated with large wildfire seasons in the Mediterranean (3.6 kPa) and the maximum VPD observed in surrounding Pyrenean mountains (3.1 kPa), we quantified the "safety margin" for Pyrenean forests (difference between actual VPD and that associated with large wildfires) at 0.5 kPa. The effects of live fuel moisture content (LFMC) on burned area were not significant under current conditions, a situation that may change with projected increases in climate aridity. Overall, our results indicate that DFMC in currently fire-free areas in Europe, like the Pyrenees, with vast amounts of fuel in many forest stands, may reach critical dryness thresholds beyond the safety margin and experience large wildfires after only mild increases in VPD, although LFMC can modulate the response.
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Affiliation(s)
- Víctor Resco de Dios
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China; Department of Crop and Forest Sciences, University of Lleida, Lleida, Spain; Joint Research Unit CTFC-AGROTECNIO, Universitat de Lleida, Lleida, Spain.
| | - Javier Hedo
- Department of Crop and Forest Sciences, University of Lleida, Lleida, Spain
| | | | - Prakash Thapa
- Master in Mediterranean Forestry, University of Lleida, Lleida, Spain
| | | | - Juan Martínez de Aragón
- Joint Research Unit CTFC-AGROTECNIO, Universitat de Lleida, Lleida, Spain; Centre de Ciència i Tecnologia Forestal de Catalunya, Solsona, Spain
| | - José Antonio Bonet
- Department of Crop and Forest Sciences, University of Lleida, Lleida, Spain; Joint Research Unit CTFC-AGROTECNIO, Universitat de Lleida, Lleida, Spain
| | - Rodrigo Balaguer-Romano
- Mathematical and Fluid Physics Department, Faculty of Sciences, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
| | - Rubén Díaz-Sierra
- Mathematical and Fluid Physics Department, Faculty of Sciences, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
| | - Marta Yebra
- Fenner School of Environment & Society, The Australian National University, Canberra, ACT, Australia; Bushfire and Natural Hazards Cooperative Research Centre, Melbourne, VIC, Australia; School of Engineering, The Australian National University, Canberra, ACT, Australia
| | - Matthias M Boer
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
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Farfán M, Dominguez C, Espinoza A, Jaramillo A, Alcántara C, Maldonado V, Tovar I, Flamenco A. Forest fire probability under ENSO conditions in a semi-arid region: a case study in Guanajuato. Environ Monit Assess 2021; 193:684. [PMID: 34599681 DOI: 10.1007/s10661-021-09494-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
Fires can pose a threat to forest ecosystems when those ecosystems are not fire-adapted or when forest community conditions make them vulnerable to wildfires. Thus, investigating fire-prone environmental conditions is urgently needed to create action plans that preserve these ecosystems. In this sense, climate variables can determine the environmental conditions favorable for forest fires. Our study confirms that vapor pressure deficit (VPD) is an essential climate indicator for forest fires, as it is related to maximum temperatures and low humidity, representing the stress conditions for vegetation prone to fires. This study explores the extent to which ENSO phases can modulate climatic conditions that lead to high VPD over Guanajuato, a semi-arid region in central Mexico, during the dry season (March-April-May). Using fire occurrence data from MODIS (2000-2019) and Landsat 5 (1998-1999), we developed a climatic probability model for the occurrence of forest fires using VPD estimated from ERA5 reanalysis for each ENSO phase. We found that VPD and the occurrence of forest fires were higher during El Niño than under Neutral and La Niña years, with a higher risk of forest fire occurrence in Guanajuato's southern region. This study concludes that it is necessary to implement regional and local fire management plans, especially where the largest number of natural protected areas is located.
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Affiliation(s)
- Michelle Farfán
- Departamento de Ingeniería Geomática e Hidráulica, División de Ingenierías, Universidad de Guanajuato, Guanajuato, Mexico
| | - Christian Dominguez
- Instituto de Ciencias de la Atmósfera y Cambio Climático, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito Exterior, 04510 Mexico City, Mexico
| | - Alejandra Espinoza
- Departamento de Ingeniería Geomática e Hidráulica, División de Ingenierías, Universidad de Guanajuato, Guanajuato, Mexico
| | - Alejandro Jaramillo
- Instituto de Ciencias de la Atmósfera y Cambio Climático, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito Exterior, 04510 Mexico City, Mexico.
| | - Camilo Alcántara
- Departamento de Ingeniería Geomática e Hidráulica, División de Ingenierías, Universidad de Guanajuato, Guanajuato, Mexico
| | - Victor Maldonado
- Departamento de Ingeniería Geomática e Hidráulica, División de Ingenierías, Universidad de Guanajuato, Guanajuato, Mexico
| | - Israel Tovar
- Departamento de Ingeniería Geomática e Hidráulica, División de Ingenierías, Universidad de Guanajuato, Guanajuato, Mexico
| | - Alejandro Flamenco
- Departamento de Ingeniería Geomática e Hidráulica, División de Ingenierías, Universidad de Guanajuato, Guanajuato, Mexico
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Deng Y, Wu S, Ke J, Zhu A. Effects of meteorological factors and groundwater depths on plant sap flow velocities in karst critical zone. Sci Total Environ 2021; 781:146764. [PMID: 33812103 DOI: 10.1016/j.scitotenv.2021.146764] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/04/2021] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
Determining water supply intensity of fracture/conduits is one of the difficulties involved in the research of plant transpiration water consumption in the Karst Critical Zone (KCZ). Our aims were to evaluate the effect of groundwater depth on plant sap flow velocities in KCZ. Thus, four sampled plots with different groundwater depth (GD) in boreholes KCZ7 (4 to 10 m GD), KCZ5 (2 to 9 m GD), KCZ1 (0 to 8 m GD) and KCZ3 (2 to 5 m GD), were selected, and the plant stem sap flow velocity in each plot were also monitored continuously and automatically using heat ratio techniques. The daily sap flow flux of Toona sinensis varied between 0.35 kg d-1 in KCZ3 and 1.50 kg d-1 in KCZ1. Photosynthetically active radiation (PAR), vapor pressure deficit (VPD), and gust velocity (ZWS) were the primary meteorological factors that determined the sap flow velocity of T. sinensis, which contributed to a regression equation, while the influence of GD on sap flow was complex. Most of the sap flow velocity had no obvious significant correlation with the GD; however, the sap flow velocity in four different GD showed significant differences (P < 0.05). Unit sap flow velocity changes induced by unit GD changes (Kv) in KCZ7 and KCZ1 samples was faster than that of other samples. In brief, the sap flow velocity was mainly affected by the PAR and VPD in KCZ7, KCZ5 and KCZ1 because of the sufficient epikarst water, while the sap flow velocity in KCZ3 was mainly affected by the rock water content. The karst aquifer medium and GD was the main factors causing the difference sap flow velocity in the four sample plots. This finding indicated that KCZ aquifer medium structure may have an important influence on plant water utilization.
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Affiliation(s)
- Yan Deng
- Institute of Karst Geology, Chinese Academic of Geological Sciences, Guilin 541004, China.
| | - Song Wu
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China
| | - Jing Ke
- Institute of Karst Geology, Chinese Academic of Geological Sciences, Guilin 541004, China
| | - Aijun Zhu
- School of Electronic Engineering and Automation, Guilin University of Electronic Technology, Guilin 541004, China
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18
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Szejner P, Belmecheri S, Babst F, Wright WE, Frank DC, Hu J, Monson RK. Stable isotopes of tree rings reveal seasonal-to-decadal patterns during the emergence of a megadrought in the Southwestern US. Oecologia 2021; 197:1079-1094. [PMID: 33870457 DOI: 10.1007/s00442-021-04916-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 04/08/2021] [Indexed: 11/24/2022]
Abstract
Recent evidence has revealed the emergence of a megadrought in southwestern North America since 2000. Megadroughts extend for at least 2 decades, making it challenging to identify such events until they are well established. Here, we examined tree-ring growth and stable isotope ratios in Pinus ponderosa at its driest niche edge to investigate whether trees growing near their aridity limit were sensitive to the megadrought climatic pre-conditions, and were capable of informing predictive efforts. During the decade before the megadrought, trees in four populations revealed increases in the cellulose δ13C content of earlywood, latewood, and false latewood, which, based on past studies are correlated with increased intrinsic water-use efficiency. However, radial growth and cellulose δ18O were not sensitive to pre-megadrought conditions. During the 2 decades preceding the megadrought, at all four sites, the changes in δ13C were caused by the high sensitivity of needle carbon and water exchange to drought trends in key winter months, and for three of the four sites during crucial summer months. Such pre-megadrought physiological sensitivity appears to be unique for trees near their arid range limit, as similar patterns were not observed in trees in ten reference sites located along a latitudinal gradient in the same megadrought domain, despite similar drying trends. Our results reveal the utility of tree-ring δ13C to reconstruct spatiotemporal patterns during the organizational phase of a megadrought, demonstrating that trees near the arid boundaries of a species' distribution might be useful in the early detection of long-lasting droughts.
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Affiliation(s)
- Paul Szejner
- Instituto de Geología, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico. .,Laboratory of Tree‑Ring Research, University of Arizona, 1215 E Lowell St, Tucson, AZ, 85721, USA.
| | - Soumaya Belmecheri
- Laboratory of Tree‑Ring Research, University of Arizona, 1215 E Lowell St, Tucson, AZ, 85721, USA
| | - Flurin Babst
- Laboratory of Tree‑Ring Research, University of Arizona, 1215 E Lowell St, Tucson, AZ, 85721, USA.,W. Szafer Institute of Botany, Polish Academy of Science, ul. Lubicz 46, 31-512, Krakow, Poland.,School of Natural Resources and the Environment, University of Arizona, 1064 E. Lowell St., Tucson, AZ, 85721, USA
| | - William E Wright
- Laboratory of Tree‑Ring Research, University of Arizona, 1215 E Lowell St, Tucson, AZ, 85721, USA
| | - David C Frank
- Laboratory of Tree‑Ring Research, University of Arizona, 1215 E Lowell St, Tucson, AZ, 85721, USA
| | - Jia Hu
- Laboratory of Tree‑Ring Research, University of Arizona, 1215 E Lowell St, Tucson, AZ, 85721, USA.,School of Natural Resources and the Environment, University of Arizona, 1064 E. Lowell St., Tucson, AZ, 85721, USA
| | - Russell K Monson
- Laboratory of Tree‑Ring Research, University of Arizona, 1215 E Lowell St, Tucson, AZ, 85721, USA.,Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
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Zhao J, Feng H, Xu T, Xiao J, Guerrieri R, Liu S, Wu X, He X, He X. Physiological and environmental control on ecosystem water use efficiency in response to drought across the northern hemisphere. Sci Total Environ 2021; 758:143599. [PMID: 33250244 DOI: 10.1016/j.scitotenv.2020.143599] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/25/2020] [Accepted: 10/30/2020] [Indexed: 06/12/2023]
Abstract
Drought, a natural hydrometeorological phenomenon, has been more frequent and more widespread due to climate change. Water availability strongly regulates the coupling (or trade-off) between carbon uptake via photosynthesis and water loss through transpiration, known as water-use efficiency (WUE). Understanding the effects of drought on WUE across different vegetation types and along the wet to dry gradient is paramount to achieving better understanding of ecosystem functioning in response to climate change. We explored the physiological and environmental control on ecosystem WUE in response to drought using observations for 44 eddy covariance flux sites in the Northern Hemisphere. We quantified the response of WUE to drought and the relative contributions of gross primary production (GPP) and evapotranspiration (ET) to the variations of WUE. We also examined the control of physiological and environmental factors on monthly WUE under different moisture conditions. Cropland had a peak WUE value under moderate drought conditions, while grassland, deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and evergreen needleleaf forest (ENF) had peak WUE under slight drought conditions. WUE was mainly driven by GPP for cropland, grassland, DBF, and ENF but was mainly driven by ET for EBF. Vapor pressure deficit (VPD) and canopy conductance (Gc) were the most important factors regulating WUE. Moreover, WUE had negative responses to air temperature, precipitation, and VPD but had a positive response to Gc and ecosystem respiration. Our findings highlight the different effects of biotic and abiotic factors on WUE among different vegetation types and the important roles of VPD and Gc in controlling ecosystem WUE in response to drought.
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Affiliation(s)
- Jingxue Zhao
- State Key Laboratory of Earth Surface Processes and Resource Ecology, School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Huaize Feng
- State Key Laboratory of Earth Surface Processes and Resource Ecology, School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Tongren Xu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China.
| | - Jingfeng Xiao
- Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, NH 03824, USA.
| | - Rossella Guerrieri
- Department of Agricultural and Food Sciences, University of Bologna, I-40127 Bologna, Italy
| | - Shaomin Liu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Xiuchen Wu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Xinlei He
- State Key Laboratory of Earth Surface Processes and Resource Ecology, School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Xiangping He
- State Key Laboratory of Earth Surface Processes and Resource Ecology, School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
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Sexton TM, Steber CM, Cousins AB. Leaf temperature impacts canopy water use efficiency independent of changes in leaf level water use efficiency. J Plant Physiol 2021; 258-259:153357. [PMID: 33465638 DOI: 10.1016/j.jplph.2020.153357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 06/12/2023]
Abstract
Canopy water use efficiency (above-ground biomass over lifetime water loss, WUEcanopy) can influence yield in wheat and other crops. Breeding for WUEcanopy is difficult because it is influenced by many component traits. For example, intrinsic water use efficiency (WUEi), the ratio of net carbon assimilation (Anet) over stomatal conductance, contributes to WUEcanopy and can be estimated from carbon isotope discrimination (Δ). However, Δ is not sensitive to differences in the water vapor pressure deficit between the air and leaf (VPDleaf). Alternatively, measurements of instantaneous leaf water use efficiency (WUEleaf) are defined as Anet over transpiration and can be determined with gas exchange, but the dynamic nature of field conditions are not represented. Specifically, fluctuations in canopy temperature lead to changes in VPDleaf that impact transpiration but not Anet. This alters WUEleaf and in turn affects WUEcanopy. To test this relationship, WUEcanopy was measured in conjunction with WUEi, WUEcanopy, and canopy temperature under well-watered and water-limited conditions in two drought-tolerant wheat cultivars that differ in canopy architecture. In this experiment, boundary layer conductance was low and significant changes in leaf temperature occurred between cultivars and treatments that correlated with WUEcanopy likely because of the effect of canopy temperature on VPDleaf driving T. However, deviations between WUEi, WUEleaf, and WUEcanopy were present because measurements made at the leaf level do not account for variations in leaf temperature. This uncoupled the relationship of measured WUEleaf and WUEi from WUEcanopy and emphasizes the importance of canopy temperature on carbon uptake and transpired water loss.
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Affiliation(s)
- Thomas M Sexton
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA, 99164-4236, United States.
| | - Camille M Steber
- USDA-ARS, Wheat Health, Genetics and Quality Unit, Pullman, WA, 99164-6420, USA; Washington State University, Dept. of Crop and Soil Sciences, Johnson Hall Room 209, Pullman, WA, 99164-6420, USA.
| | - Asaph B Cousins
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA, 99164-4236, United States.
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21
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Song X, Bai P, Ding J, Li J. Effect of vapor pressure deficit on growth and water status in muskmelon and cucumber. Plant Sci 2021; 303:110755. [PMID: 33487342 DOI: 10.1016/j.plantsci.2020.110755] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 08/21/2020] [Accepted: 11/05/2020] [Indexed: 06/12/2023]
Abstract
Climatic warming and water shortages have become global environmental issues affecting agricultural production. The change of morphology and anatomical structures in plant organs can greatly affect plant growth. The study combined temperature and relative humidity to regulate vapor pressure deficit (VPD) to form low and high VPD environments (LVPD and HVPD, respectively) in two climate-controlled greenhouses. The effects of different VPD conditions on gas exchange parameters, dry matter, and leaf and stem anatomical structure parameters of muskmelon and cucumber were compared and studied. The results show that the background VPD conditions give different internal structure of muskmelon and cucumber, therefore it can improve the transport capacity of water to the leaf surface under LVPD conditions. At the same time, the stomatal closure induced by atmospheric drought stress is avoided and the gas exchange capacity of the leaf stomata is enhanced, thereby maintaining high photosynthetic rate. Thus, reducing VPD is the key to achieving high yield and productivity in greenhouse muskmelon and cucumber production.
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Affiliation(s)
- Xiaoming Song
- College of Horticulture, Northwest Agriculture & Forest University, Yangling, 712100, Shaanxi, China.
| | - Ping Bai
- College of Horticulture, Northwest Agriculture & Forest University, Yangling, 712100, Shaanxi, China.
| | - Juping Ding
- College of Horticulture, Northwest Agriculture & Forest University, Yangling, 712100, Shaanxi, China.
| | - Jianming Li
- College of Horticulture, Northwest Agriculture & Forest University, Yangling, 712100, Shaanxi, China.
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Kar S, Tanaka R, Korbu LB, Kholová J, Iwata H, Durbha SS, Adinarayana J, Vadez V. Automated discretization of 'transpiration restriction to increasing VPD' features from outdoors high-throughput phenotyping data. Plant Methods 2020; 16:140. [PMID: 33072176 PMCID: PMC7565372 DOI: 10.1186/s13007-020-00680-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 10/05/2020] [Indexed: 05/24/2023]
Abstract
BACKGROUND Restricting transpiration under high vapor pressure deficit (VPD) is a promising water-saving trait for drought adaptation. However, it is often measured under controlled conditions and at very low throughput, unsuitable for breeding. A few high-throughput phenotyping (HTP) studies exist, and have considered only maximum transpiration rate in analyzing genotypic differences in this trait. Further, no study has precisely identified the VPD breakpoints where genotypes restrict transpiration under natural conditions. Therefore, outdoors HTP data (15 min frequency) of a chickpea population were used to automate the generation of smooth transpiration profiles, extract informative features of the transpiration response to VPD for optimal genotypic discretization, identify VPD breakpoints, and compare genotypes. RESULTS Fifteen biologically relevant features were extracted from the transpiration rate profiles derived from load cells data. Genotypes were clustered (C1, C2, C3) and 6 most important features (with heritability > 0.5) were selected using unsupervised Random Forest. All the wild relatives were found in C1, while C2 and C3 mostly comprised high TE and low TE lines, respectively. Assessment of the distinct p-value groups within each selected feature revealed highest genotypic variation for the feature representing transpiration response to high VPD condition. Sensitivity analysis on a multi-output neural network model (with R of 0.931, 0.944, 0.953 for C1, C2, C3, respectively) found C1 with the highest water saving ability, that restricted transpiration at relatively low VPD levels, 56% (i.e. 3.52 kPa) or 62% (i.e. 3.90 kPa), depending whether the influence of other environmental variables was minimum or maximum. Also, VPD appeared to have the most striking influence on the transpiration response independently of other environment variable, whereas light, temperature, and relative humidity alone had little/no effect. CONCLUSION Through this study, we present a novel approach to identifying genotypes with drought-tolerance potential, which overcomes the challenges in HTP of the water-saving trait. The six selected features served as proxy phenotypes for reliable genotypic discretization. The wild chickpeas were found to limit water-loss faster than the water-profligate cultivated ones. Such an analytic approach can be directly used for prescriptive breeding applications, applied to other traits, and help expedite maximized information extraction from HTP data.
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Affiliation(s)
- Soumyashree Kar
- Centre of Studies in Resources Engineering, Indian Institute of Technology Bombay, Mumbai, India 400076
| | - Ryokei Tanaka
- Laboratory of Biometrics and Bioinformatics, University of Tokyo, Tokyo, Japan
| | - Lijalem Balcha Korbu
- Debre Zeit Research Center, Ethiopian Institute of Agricultural Research (EIAR), Debre Zeit, Ethiopia
| | - Jana Kholová
- International Crop Research Institute for Semi-Arid Tropics, Hyderabad, India 502319
| | - Hiroyoshi Iwata
- Laboratory of Biometrics and Bioinformatics, University of Tokyo, Tokyo, Japan
| | - Surya S. Durbha
- Centre of Studies in Resources Engineering, Indian Institute of Technology Bombay, Mumbai, India 400076
| | - J. Adinarayana
- Centre of Studies in Resources Engineering, Indian Institute of Technology Bombay, Mumbai, India 400076
| | - Vincent Vadez
- International Crop Research Institute for Semi-Arid Tropics, Hyderabad, India 502319
- Institut de Recherche Pour Le Développement (IRD), Université de Montpellier—UMR DIADE, 911 Avenue Agropolis, BP 64501, 34394 Montpellier cedex 5, France
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Liu X, Feng X, Fu B. Changes in global terrestrial ecosystem water use efficiency are closely related to soil moisture. Sci Total Environ 2020; 698:134165. [PMID: 31494420 DOI: 10.1016/j.scitotenv.2019.134165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 06/10/2023]
Abstract
Ecosystem water use efficiency (WUE), defined as the ratio between gross primary productivity (GPP) and evapotranspiration (ET), is an indicator of the tradeoff between carbon assimilation and water loss that is controlled by climate and ecosystem structure. However, how GPP and ET impact WUE remains poorly understood. In this study, we provide a global analysis of WUE trends from 1982 to 2011 using multi-model ensemble mean WUE values derived from seven process-based carbon cycle models and investigate the relative effects of leaf area index (LAI), soil moisture (SM), and vapor pressure deficit (VPD) on GPP and ET. Increasing WUE trend was derived for all models, with an average rate of 0.0057 ± 0.0018 g C·kg-1 H2O·yr-1 (p = 0.00), with a spatially increasing WUE across ~84% of the global land area, and increasing trends which are statistically significant over ~72% (p < 0.05). Spatially, GPP primarily dominated WUE variability in humid regions, i.e., boreal Eurasia, eastern America, and the tropics, whereas ET dominated WUE variability in dryland regions, i.e., northeast China, the Middle East, southern South America, and South Australia. Soil moisture is likely the most influential factor on GPP and ET variations, with ~63% and ~61% of the global land area dominated by SM, and therefore WUE, for GPP and ET respectively from 1982 to 2011. Our findings enrich the understanding of WUE trends and provide direct evidence for SM-induced variability in WUE.
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Affiliation(s)
- Xianfeng Liu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China; State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xiaoming Feng
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Bojie Fu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Wang X, Qiu B, Li W, Zhang Q. Impacts of drought and heatwave on the terrestrial ecosystem in China as revealed by satellite solar-induced chlorophyll fluorescence. Sci Total Environ 2019; 693:133627. [PMID: 31377349 DOI: 10.1016/j.scitotenv.2019.133627] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/23/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Droughts and heatwaves have been and will continue to bring large risks to terrestrial ecosystems. However, the understanding of how plants respond to drought and heatwave over broad spatial scales is still limited. In this paper, we use the 2009/2010 drought in Yunnan and the 2013 heatwave over southern China as case studies to investigate the potential of using satellite-observed solar-induced chlorophyll fluorescence (SIF) to monitor vegetation responses to drought and heatwave over broad spatial scales. The 2009/2010 drought onset follows a strong soil moisture deficit due to the yearlong below-normal precipitation in Yunnan from the autumn of 2009 to the spring of 2010. In the summer of 2013, southern China experienced the strongest heatwave due to the sudden temperature increase and rainfall deficit. The results show that SIF can reasonably capture the spatial and temporal dynamics of drought and heatwave development, as indicated by the large reduction in fluorescence yield (SIFyield). Moreover, SIFyield demonstrates a significant reduction and earlier response than traditional vegetation indices (enhanced vegetation index, EVI) during the early stages of drought and heatwave events. For both study areas, the spatial and temporal correlation analysis demonstrates that the SIFyield anomalies are more sensitive to a high vapor pressure deficit (VPD) than low soil moisture. This study implies that satellite observations of SIF have great potential for accurate and timely monitoring of drought and heatwave developments.
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Affiliation(s)
- Xiaorong Wang
- Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, International Institute for Earth System Sciences, Nanjing University, Nanjing, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, China
| | - Bo Qiu
- Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, International Institute for Earth System Sciences, Nanjing University, Nanjing, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, China.
| | - Wenkai Li
- Key Laboratory of Meteorological Disaster, Ministry of Education (KLME)/Joint International Research Laboratory of Climate and Environment Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing, China
| | - Qian Zhang
- Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, International Institute for Earth System Sciences, Nanjing University, Nanjing, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, China
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25
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Tamang BG, Schoppach R, Monnens D, Steffenson BJ, Anderson JA, Sadok W. Variability in temperature-independent transpiration responses to evaporative demand correlate with nighttime water use and its circadian control across diverse wheat populations. Planta 2019; 250:115-127. [PMID: 30941570 DOI: 10.1007/s00425-019-03151-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 03/25/2019] [Indexed: 06/09/2023]
Abstract
Nocturnal transpiration, through its circadian control, plays a role in modulating daytime transpiration response to increasing evaporative demand, to potentially enable drought tolerance in wheat. Limiting plant transpiration rate (TR) in response to increasing vapor pressure deficit (VPD) has been suggested to enable drought tolerance through water conservation. However, there is very little information on the extent of diversity of TR response curves to "true" VPD (i.e., independent from temperature). Furthermore, new evidence indicate that water-saving could operate by modulating nocturnal TR (TRN), and that this response might be coupled to daytime gas exchange. Based on 3 years of experimental data on a diverse group of 77 genotypes from 25 countries and 5 continents, a first goal of this study was to characterize the functional diversity in daytime TR responses to VPD and TRN in wheat. A second objective was to test the hypothesis that these traits could be coupled through the circadian clock. Using a new gravimetric phenotyping platform that allowed for independent temperature and VPD control, we identified three and fourfold variation in daytime and nighttime responses, respectively. In addition, TRN was found to be positively correlated with slopes of daytime TR responses to VPD, and we identified pre-dawn variation in TRN that likely mediated this relationship. Furthermore, pre-dawn increase in TRN positively correlated with the year of release among drought-tolerant Australian cultivars and with the VPD threshold at which they initiated water-saving. Overall, the study indicates a substantial diversity in TR responses to VPD that could be leveraged to enhance fitness under water-limited environments, and that TRN and its circadian control may play an important role in the expression of water-saving.
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Affiliation(s)
- Bishal G Tamang
- Department of Agronomy and Plant Genetics, University of Minnesota Twin Cities, Twin Cities, MN, USA
| | - Rémy Schoppach
- Department of Agronomy and Plant Genetics, University of Minnesota Twin Cities, Twin Cities, MN, USA
- Earth and Life Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Daniel Monnens
- Department of Agronomy and Plant Genetics, University of Minnesota Twin Cities, Twin Cities, MN, USA
| | - Brian J Steffenson
- Department of Plant Pathology, University of Minnesota, Twin Cities, MN, USA
| | - James A Anderson
- Department of Agronomy and Plant Genetics, University of Minnesota Twin Cities, Twin Cities, MN, USA
| | - Walid Sadok
- Department of Agronomy and Plant Genetics, University of Minnesota Twin Cities, Twin Cities, MN, USA.
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26
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Jhou HC, Wang YN, Wu CS, Yu JC, Chen CI. Photosynthetic gas exchange responses of Swietenia macrophylla King and Melia azedarach L. plantations under drought conditions. Bot Stud 2017; 58:57. [PMID: 29198038 PMCID: PMC5712295 DOI: 10.1186/s40529-017-0212-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 11/23/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND The environmental stresses caused by climate change have become more severe in recent decades, affecting tree growth and physiology. Tropical forests have great potential for global carbon sequestration. However, they suffer from heavy rainfall and prolonged dry periods due to climate change. Swietenia macrophylla King and Melia azedarach L. are economically valuable trees that are widely planted in southern Taiwan. Plantations are exposed to either prolonged dry periods or heavy rainfall within the seasons of tropical monsoon areas. Photo-physiological comparisons may provide information that can improve management of S. macrophylla and M. azedarach plantations in tropical regions. RESULTS Both species exhibited a midday depression in leaf photosynthesis regardless of the season. The net photosynthetic rate (P N), stomatal conductance (g s), and transpiration rate (E) in the dry season all significantly decreased in both tree species. In addition, M. azedarach used water more efficiently than did S. macrophylla during the dry season, but S. macrophylla had higher P N compared with that in M. azedarach during the wet season. Temperature and vapor pressure deficit influenced P N variation in S. macrophylla and M. azedarach, respectively. Our data suggested that the P N and g s of M. azedarach, but not of S. macrophylla, were linearly correlated during the dry season. The reduction of the leaf area was more sever in M. azedarach than in S. macrophylla, thus preventing water loss more efficiently. CONCLUSIONS M. azedarach adapted to drought by reducing total leaf area and maintaining higher P N, g s, E, and WUE compared with those measured in S. macrophylla during the dry season. M. azedarach is more drought adaptation and more suitable for both humid and semi-humid areas than S. macrophylla, whereas the latter should be limited to more humid areas.
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Affiliation(s)
- Hong-Chyi Jhou
- The Experimental Forest, National Taiwan University, 55750 Nantou, Taiwan
| | - Ya-Nan Wang
- Department of Forestry and Resource Conservation, National Taiwan University, 10617 Taipei, Taiwan
| | - Chung-Shien Wu
- Biodiversity Research Center, Academia Sinica, 11529 Taipei, Taiwan
| | - Jui-Chu Yu
- The Experimental Forest, National Taiwan University, 55750 Nantou, Taiwan
| | - Chung-I Chen
- Department of Forestry and Resource Conservation, National Taiwan University, 10617 Taipei, Taiwan
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27
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Wagle P, Gowda PH, Anapalli SS, Reddy KN, Northup BK. Growing season variability in carbon dioxide exchange of irrigated and rainfed soybean in the southern United States. Sci Total Environ 2017; 593-594:263-273. [PMID: 28346900 DOI: 10.1016/j.scitotenv.2017.03.163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/16/2017] [Accepted: 03/18/2017] [Indexed: 06/06/2023]
Abstract
Measurement of carbon dynamics of soybean (Glycine max L.) ecosystems outside Corn Belt of the United States (U.S.) is lacking. This study examines the seasonal variability of net ecosystem CO2 exchange (NEE) and its components (gross primary production, GPP and ecosystem respiration, ER), and relevant controlling environmental factors between rainfed (El Reno, Oklahoma) and irrigated (Stoneville, Mississippi) soybean fields in the southern U.S. during the 2016 growing season. Grain yield was about 1.6tha-1 for rainfed soybean and 4.9tha-1 for irrigated soybean. The magnitudes of diurnal NEE (~2-weeks average) reached seasonal peak values of -23.18 and -34.78μmolm-2s-1 in rainfed and irrigated soybean, respectively, approximately two months after planting (i.e., during peak growth). Similar thresholds of air temperature (Ta, slightly over 30°C) and vapor pressure deficit (VPD, ~2.5kPa) for NEE were observed at both sites. Daily (7-day average) NEE, GPP, and ER reached seasonal peak values of -4.55, 13.54, and 9.95gCm-2d-1 in rainfed soybean and -7.48, 18.13, and 14.93gCm-2d-1 in irrigated soybean, respectively. The growing season (DOY 132-243) NEE, GPP, and ER totals were -54, 783, and 729gCm-2, respectively, in rainfed soybean. Similarly, cumulative NEE, GPP, and ER totals for DOY 163-256 (flux measurement was initiated on DOY 163, missing first 45days after planting) were -291, 1239, and 948gCm-2, respectively, in irrigated soybean. Rainfed soybean was a net carbon sink for only two months, while irrigated soybean appeared to be a net carbon sink for about three months. However, grain yield and the magnitudes and seasonal sums of CO2 fluxes for irrigated soybean in this study were comparable to those for soybean in the U.S. Corn Belt, but they were lower for rainfed soybean.
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Affiliation(s)
- Pradeep Wagle
- Forage and Livestock Production Research Unit, USDA-ARS Grazinglands Research Laboratory, El Reno, OK 73036, USA.
| | - Prasanna H Gowda
- Forage and Livestock Production Research Unit, USDA-ARS Grazinglands Research Laboratory, El Reno, OK 73036, USA
| | - Saseendran S Anapalli
- Crop Production Systems Research Unit, USDA-ARS Southeast Area, Stoneville, MS 38766, USA
| | - Krishna N Reddy
- Crop Production Systems Research Unit, USDA-ARS Southeast Area, Stoneville, MS 38766, USA
| | - Brian K Northup
- Forage and Livestock Production Research Unit, USDA-ARS Grazinglands Research Laboratory, El Reno, OK 73036, USA
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Sinclair TR, Devi J, Shekoofa A, Choudhary S, Sadok W, Vadez V, Riar M, Rufty T. Limited-transpiration response to high vapor pressure deficit in crop species. Plant Sci 2017; 260:109-118. [PMID: 28554468 DOI: 10.1016/j.plantsci.2017.04.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 03/28/2017] [Accepted: 04/07/2017] [Indexed: 05/08/2023]
Abstract
Water deficit under nearly all field conditions is the major constraint on plant yields. Other than empirical observations, very little progress has been made in developing crop plants in which specific physiological traits for drought are expressed. As a consequence, there was little known about under what conditions and to what extent drought impacts crop yield. However, there has been rapid progress in recent years in understanding and developing a limited-transpiration trait under elevated atmospheric vapor pressure deficit to increase plant growth and yield under water-deficit conditions. This review paper examines the physiological basis for the limited-transpiration trait as result of low plant hydraulic conductivity, which appears to be related to aquaporin activity. Methodology was developed based on aquaporin involvement to identify candidate genotypes for drought tolerance of several major crop species. Cultivars of maize and soybean are now being marketed specifically for arid conditions. Understanding the mechanism of the limited-transpiration trait has allowed a geospatial analyses to define the environments in which increased yield responses can be expected. This review highlights the challenges and approaches to finally develop physiological traits contributing directly to plant improvement for water-limited environments.
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Affiliation(s)
- Thomas R Sinclair
- Crop Science Department, North Carolina State University, Raleigh, NC 27695-7620, USA.
| | - Jyostna Devi
- Crop Science Department, North Carolina State University, Raleigh, NC 27695-7620, USA
| | - Avat Shekoofa
- Crop Science Department, North Carolina State University, Raleigh, NC 27695-7620, USA
| | - Sunita Choudhary
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502324, Greater Hyderabad, Telangana, India
| | - Walid Sadok
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108-6026, USA
| | - Vincent Vadez
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502324, Greater Hyderabad, Telangana, India
| | - Mandeep Riar
- Crop Science Department, North Carolina State University, Raleigh, NC 27695-7620, USA
| | - Thomas Rufty
- Crop Science Department, North Carolina State University, Raleigh, NC 27695-7620, USA
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Carvalho DRA, Vasconcelos MW, Lee S, Koning-Boucoiran CFS, Vreugdenhil D, Krens FA, Heuvelink E, Carvalho SMP. Gene expression and physiological responses associated to stomatal functioning in Rosa×hybrida grown at high relative air humidity. Plant Sci 2016; 253:154-163. [PMID: 27968984 DOI: 10.1016/j.plantsci.2016.09.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/02/2016] [Accepted: 09/30/2016] [Indexed: 06/06/2023]
Abstract
High relative air humidity (RH≥85%) during growth disturbs stomatal functioning, resulting in excessive water loss in conditions of high evaporative demand. We investigated the expression of nine abscisic acid (ABA)-related genes (involved in ABA biosynthesis, oxidation and conjugation) and two non-ABA related genes (involved in the water stress response) aiming to better understand the mechanisms underlying contrasting stomatal functioning in plants grown at high RH. Four rose genotypes with contrasting sensitivity to high RH (one sensitive, one tolerant and two intermediate) were grown at moderate (62±3%) or high (89±4%) RH. The sensitive genotype grown at high RH showed a significantly higher stomatal conductance (gs) and water loss in response to closing stimuli as compared to the other genotypes. Moreover, high RH reduced the leaf ABA concentration and its metabolites to a greater extent in the sensitive genotype as compared to the tolerant one. The large majority of the studied genes had a relevant role on stomatal functioning (NCED1, UGT75B2, BG2, OST1, ABF3 and Rh-APX) while two others showed a minor contribution (CYP707A3 and BG1) and AAO3, CYP707A1 and DREB1B did not contribute to the tolerance trait. These results show that multiple genes form a highly complex regulatory network acting together towards the genotypic tolerance to high RH.
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Affiliation(s)
- Dália R A Carvalho
- CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal.
| | - Marta W Vasconcelos
- CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal
| | - Sangseok Lee
- Plant Sciences Group, Wageningen University, Plant Physiology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands; Gyeongsangbuk-Do Agricultural Research & Extension Services, 136 Gil-14, Chilgokiungang-Daero, Daegu, South Korea
| | - Carole F S Koning-Boucoiran
- Plant Sciences Group, Wageningen University, Plant Breeding, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Dick Vreugdenhil
- Plant Sciences Group, Wageningen University, Plant Physiology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Frans A Krens
- Plant Sciences Group, Wageningen University, Plant Breeding, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Ep Heuvelink
- Plant Sciences Group, Wageningen University, Horticulture and Product Physiology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Susana M P Carvalho
- CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal; Plant Sciences Group, Wageningen University, Horticulture and Product Physiology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands; GreenUP/CITAB-UP & DGAOT, Faculty of Sciences, University of Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas, 7. 4485-661 Vairão, Portugal.
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Paltineanu C, Septar L, Chitu E. Temperature profile in apricot tree canopies under the soil and climate conditions of the Romanian Black Sea Coast. Int J Biometeorol 2016; 60:401-410. [PMID: 26188664 DOI: 10.1007/s00484-015-1037-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 05/05/2015] [Accepted: 05/15/2015] [Indexed: 06/04/2023]
Abstract
The paper describes the temperature profiles determined by thermal imagery in apricot tree canopies under the semi-arid conditions of the Black Sea Coast in a chernozem of Dobrogea Region, Romania. The study analyzes the thermal vertical profile of apricot orchards for three representative cultivars during summertime. Measurements were done when the soil water content (SWC) was at field capacity (FC) within the rooting depth, after intense sprinkler irrigation applications. Canopy temperature was measured during clear sky days at three heights for both sides of the apricot trees, sunlit (south), and shaded (north). For the SWC studied, i.e., FC, canopy height did not induce a significant difference between the temperature of apricot tree leaves (Tc) and the ambient air temperature (Ta) within the entire vertical tree profile, and temperature measurements by thermal imagery can therefore be taken at any height on the tree crown leaves. Differences between sunlit and shaded sides of the canopy were significant. Because of these differences for Tc-Ta among the apricot tree cultivars studied, lower base lines (LBLs) should be determined for each cultivar separately. The use of thermal imagery technique under the conditions of semi-arid coastal areas with low range of vapor pressure deficit could be useful in irrigation scheduling of apricot trees. The paper discusses the implications of the data obtained in the experiment under the conditions of the coastal area of the Black Sea, Romania, and neighboring countries with similar climate, such as Bulgaria and Turkey.
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Affiliation(s)
- Cristian Paltineanu
- Research Station for Fruit Growing Constanta, Romania, Pepinierei st., no. 1, Valu lui Traian, Constanta, Romania.
| | - Leinar Septar
- Research Station for Fruit Growing Constanta, Romania, Pepinierei st., no. 1, Valu lui Traian, Constanta, Romania
| | - Emil Chitu
- Research Institute for Fruit Growing Pitesti-Maracineni, Maracineni, Romania
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Shekoofa A, Rosas-Anderson P, Carley DS, Sinclair TR, Rufty TW. Limited transpiration under high vapor pressure deficits of creeping bentgrass by application of Daconil-Action. Planta 2016; 243:421-7. [PMID: 26438219 DOI: 10.1007/s00425-015-2417-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 09/23/2015] [Indexed: 05/10/2023]
Abstract
First observation that chemical spray can induce limited-transpiration rate under high vapor pressure deficit. It appears that acibenzolar may be key in inducing this water conservation trait. Irrigation and water use have become major issues in management of turfgrasses. Plant health products that have been introduced into the turfgrass market have been observed to improve plant performance in water stress conditions. In this study, we evaluated whether a selection of common plant health products alter the ability of creeping bentgrass (Agrostis stolonifera L.) to control transpiration under high vapor pressure deficit (VPD). The plant health treatments--Daconil Action, Insignia, and Signature--were applied to plots on golf course putting greens located in Raleigh NC and in Scottsdale, AZ. Using intact cores removed from the putting greens, transpiration rates were measured over a range of VPDs in controlled conditions. In all cases stretching over a 3-year period, bentgrass cores from field plots treated with Daconil-Action limited transpiration under high VPD conditions, while check treatments with water, and others treated with Insignia or Signature did not. Transpiration control became engaged when VPDs reached values ranging from 1.39 to 2.50 kPa, and was not strongly influenced by the field temperature at which the bentgrass was growing. Because all plots in NC had been treated with chlorothalonil-the key ingredient in Daconil Action to control diseases-it was concluded that the likely chemical ingredient in Daconil Action triggering the transpiration control response was acibenzolar. This is the first evidence that the limited-transpiration trait can be induced by a chemical application, and it implies significant potential for ameliorating drought vulnerability in cool-season turfgrasses, and likely other plant species.
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Affiliation(s)
- Avat Shekoofa
- Department of Crop Science, North Carolina State University, Box 7620, Raleigh, NC, 27695-7620, USA
| | - Pablo Rosas-Anderson
- Department of Crop Science, North Carolina State University, Box 7620, Raleigh, NC, 27695-7620, USA
| | - Danesha S Carley
- Department of Crop Science, North Carolina State University, Box 7620, Raleigh, NC, 27695-7620, USA
| | - Thomas R Sinclair
- Department of Crop Science, North Carolina State University, Box 7620, Raleigh, NC, 27695-7620, USA.
| | - Thomas W Rufty
- Department of Crop Science, North Carolina State University, Box 7620, Raleigh, NC, 27695-7620, USA
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Gong C, Wang J, Hu C, Wang J, Ning P, Bai J. Interactive response of photosynthetic characteristics in Haloxylon ammodendron and Hedysarum scoparium exposed to soil water and air vapor pressure deficits. J Environ Sci (China) 2015; 34:184-96. [PMID: 26257361 DOI: 10.1016/j.jes.2015.03.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 03/17/2015] [Accepted: 03/20/2015] [Indexed: 05/27/2023]
Abstract
C4 plants possess better drought tolerance than C3 plants. However, Hedysarum scoparium, a C3 species, is dominant and widely distributed in the desert areas of northwestern China due to its strong drought tolerance. This study compared it with Haloxylon ammodendron, a C4 species, regarding the interactive effects of drought stress and different leaf-air vapor pressure deficits. Variables of interest included gas exchange, the activity levels of key C4 photosynthetic enzymes, and cellular anatomy. In both species, gas exchange parameters were more sensitive to high vapor pressure deficit than to strong water stress, and the net CO2 assimilation rate (An) was enhanced as vapor pressure deficits increased. A close relationship between An and stomatal conductance (gs) suggested that the species shared a similar response mechanism. In H. ammodendron, the activity levels of key C4 enzymes were higher, including those of phosphoenolpyruvate carboxylase (PEPC) and nicotinamide adenine dinucleotide phosphate-malate enzyme (NADP-ME), whereas in H. scoparium, the activity level of nicotinamide adenine dinucleotide-malate enzyme (NAD-ME) was higher. Meanwhile, H. scoparium utilized adaptive structural features, including a larger relative vessel area and a shorter distance from vein to stomata, which facilitated the movement of water. These findings implied that some C4 biochemical pathways were present in H. scoparium to respond to environmental challenges.
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Affiliation(s)
- Chunmei Gong
- College of Life Sciences, Northwest A&F University, Yangling 712100, China.
| | - Jiajia Wang
- College of Life Sciences, Northwest A&F University, Yangling 712100, China
| | - Congxia Hu
- College of Life Sciences, Northwest A&F University, Yangling 712100, China
| | - Junhui Wang
- College of Life Sciences, Northwest A&F University, Yangling 712100, China
| | - Pengbo Ning
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Juan Bai
- College of Life Sciences, Northwest A&F University, Yangling 712100, China
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Oren R, Pataki DE. Transpiration in response to variation in microclimate and soil moisture in southeastern deciduous forests. Oecologia 2001; 127:549-559. [PMID: 28547493 DOI: 10.1007/s004420000622] [Citation(s) in RCA: 189] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2000] [Accepted: 12/06/2000] [Indexed: 11/26/2022]
Abstract
Responses of forests to changes in environmental conditions reflect the integrated behavior of their constituent species. We investigated sap flux-scaled transpiration responses of two species prevalent in upland eastern hardwood forests, Quercus alba in the upper canopy and Acer rubrum in the low to mid canopy, to changes in photosynthetically active radiation above the canopy (Q o), vapor pressure deficit within the canopy (D), and soil moisture depletion during an entire growing season. Water loss before bud break (presumably through the bark) increased linearly with D, reaching 8% of daily stand transpiration (E C) as measured when leaf area index was at maximum, and accounting for 5% of annual water loss. After leaves were completely expanded and when soil moisture was high, sap flux-scaled daily E C increased linearly with the daily sum of Q o. Species differences in this response were observed. Q. alba reached a maximum transpiration at low Q o, while A. rubrum showed increasing transpiration with Q o at all light levels. Daily E C increased in response to daily average D, with an asymptotic response due to the behavior of Q. alba. Transpiration of A. rubrum showed a greater response to soil moisture depletion than did that of Q. alba. When evaluated at a half-hourly scale under high Q o, mean canopy stomatal conductance (G S) of individuals decreased with D. The sensitivity of G S to D was greater in species with higher intrinsic G S. Regardless of position in the canopy, diffuse-porous species in this and an additional, more mesic stand showed higher G S and greater stomatal sensitivity to environmental variation than do ring-porous species.
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Affiliation(s)
- Ram Oren
- School of the Environment, Duke University, 27708-0328, Durham, NC, USA
| | - Diane E Pataki
- School of the Environment, Duke University, 27708-0328, Durham, NC, USA
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Tinoco-Ojanguren C, Pearcy RW. Stomatal dynamics and its importance to carbon gain in two rainforest Piper species : I. VPD effects on the transient stomatal response to lightflecks. Oecologia 1993; 94:388-394. [PMID: 28313676 DOI: 10.1007/bf00317114] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/1992] [Accepted: 02/23/1993] [Indexed: 11/26/2022]
Abstract
The effects of leaf-air vapor pressure deficit (VPD) on the transient and steady-state stomatal responses to photon flux density (PFD) were evaluated in Piper auritum, a pioneer tree, and Piper aequale, a shade tolerant shrub, that are both native to tropical forests at Los Tuxtlas, Veracruz, México. Under constant high-PFD conditions, the stomata of shade-acclimated plants of both species were sensitive to VPD, exhibiting a nearly uniform decrease in gs as VPD increased. Acclimation of P. auritum to high light increased the stomatal sensitivity to VPD that was sufflcient to cause a reduction in transpiration at high VPD's. At low PFD, where gs was already reduced, there was little additional absolute change with VPD for any species or growth condition. The stomatal response to 8-min duration lightflecks was strongly modulated by VPD and varied between the species and growth light conditions. In P. aequale shade plants, increased VPD had no effect on the extent of stomatal opening but caused the rate of closure after the lightfleck to be faster. Thus, the overall response to a lightfleck changed from hysteretic (faster opening than closure) to symmetric (similar opening and closing rates). Either high or low VPD caused gs not to return to the steady-state value present before the lightfleck. At high VPD the value after was considerably less than the value before whereas at low VPD the opposite occurred. Shade-acclimated plants of P. auritum showed only a small gs response to lightflecks, which was not affected by VPD. Under sunfleck regimes in the understory, the stomatal response of P. aequale at low VPD may function to enhance carbon gain by increasing the induction state. At high VPD, the shift in the response enhances water use efficiency but at the cost of reduced assimilation.
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Affiliation(s)
| | - Robert W Pearcy
- Department of Botany, University of California, 95616, Davis, CA, USA
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