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Fang W, Liu J, Lu N, Li R. The dynamics of nocturnal sap flow components of a typical revegetation shrub species on the semiarid Loess Plateau, China. FRONTIERS IN PLANT SCIENCE 2024; 15:1370362. [PMID: 38576789 PMCID: PMC10991760 DOI: 10.3389/fpls.2024.1370362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 03/11/2024] [Indexed: 04/06/2024]
Abstract
Introduction The components of nighttime sap flux (En), which include transpiration (Qn) and stem water recharge (Rn), play important roles in water balance and drought adaptation in plant communities in water-limited regions. However, the quantitative and controlling factors of En components are unclear. Methods This study used the heat balance method to measure sap flow density in Vitex negundo on the Loess Plateau for a normal precipitation year (2021) and a wetter year (2022). Results The results showed that the mean values were 1.04 and 2.34 g h-1 cm-2 for Qn, 0.19 and 0.45 g h-1 cm-2 for Rn in 2021 and 2022, respectively, and both variables were greater in the wetter year. The mean contributions of Qn to En were 79.76% and 83.91% in 2021 and 2022, respectively, indicating that the En was mostly used for Qn. Although the vapor pressure deficit (VPD), air temperature (Ta) and soil water content (SWC) were significantly correlated with Qn and Rn on an hourly time scale, they explained a small fraction of the variance in Qn on a daily time scale. The main driving factor was SWC between 40-200 cm on a monthly time scale for the Qn and Rn variations. Rn was little affected by meteorological and SWC factors on a daily scale. During the diurnal course, Qn and Rn initially both declined after sundown because of decreasing VPD and Ta, and Qn was significantly greater than Rn, whereas the two variables increased when VPD was nearly zero and Ta decreased, and Rn was greater than Qn. Discussion These results provided a new understanding of ecophysiological responses and adaptation of V. negundo plantations to increasing drought severity and duration under climate changes.
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Affiliation(s)
- Weiwei Fang
- Key Research Institute of Yellow Civilization and Sustainable Development and Collaborative Innovation Center of Henan Province, Henan University, Kaifeng, China
| | - Jianbo Liu
- Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin, China
| | - Nan Lu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ruiping Li
- Key Research Institute of Yellow Civilization and Sustainable Development and Collaborative Innovation Center of Henan Province, Henan University, Kaifeng, China
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Xue R, Jiao L, Zhang P, Du D, Wu X, Wei M, Li Q, Wang X, Qi C. The key role of ecological resilience in radial growth processes of conifers under drought stress in the subalpine zone of marginal deserts. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166864. [PMID: 37683873 DOI: 10.1016/j.scitotenv.2023.166864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/03/2023] [Accepted: 09/03/2023] [Indexed: 09/10/2023]
Abstract
Global climate change is exacerbating drought pressure on forests. However, the response patterns and physiological mechanisms of conifer species to drought, specifically in terms of radial growth, ecological resilience and soil water utilization, are not clearly understood. This study aims to quantify the effects of resilience on radial growth and identify the role of soil moisture utilization strategies in the resilience of species under drought intensities. We focus on two conifer species, Picea crassifolia (spruce) and Pinus tabuliformis (pine), located on the southern edge of the Tengger Desert in northwestern China. The dynamics of radial growth and ecological resilience were identified, and the seasonal growth rates of species based on soil water were simulated using the VS-oscilloscope model under varying drought stress. The results showed that spruce growth and recovery contributed by soil water were suppressed with frequent severe droughts, leading to a decline in growth (-0.5 cm2 year-1/10a, p < 0.05), despite its greater resistance to mild and moderate drought (-4.63 %). However, pine exhibited a stronger recovery (+40.25 %, p < 0.05) and higher variation in growth (-0.3 cm2 year-1/10a, p < 0.05) under soil moisture stress, despite its weaker resistance to drought (-23.53 %, p < 0.05). These findings provide insights into the growth, resilience, and water adaptation mechanisms of species under drought events, and theoretical support for the conservation and management of conifer diversity and forest ecosystem stability in climate-sensitive regions.
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Affiliation(s)
- Ruhong Xue
- College of Geography and Environmental Science, Northwest Normal University, No. 967, Anning East Road, Lanzhou 730070, China; Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Northwest Normal University, Lanzhou 730070, China
| | - Liang Jiao
- College of Geography and Environmental Science, Northwest Normal University, No. 967, Anning East Road, Lanzhou 730070, China; Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Northwest Normal University, Lanzhou 730070, China.
| | - Peng Zhang
- College of Geography and Environmental Science, Northwest Normal University, No. 967, Anning East Road, Lanzhou 730070, China; Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Northwest Normal University, Lanzhou 730070, China
| | - Dashi Du
- College of Geography and Environmental Science, Northwest Normal University, No. 967, Anning East Road, Lanzhou 730070, China; Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Northwest Normal University, Lanzhou 730070, China
| | - Xuan Wu
- College of Geography and Environmental Science, Northwest Normal University, No. 967, Anning East Road, Lanzhou 730070, China; Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Northwest Normal University, Lanzhou 730070, China
| | - Mengyuan Wei
- College of Geography and Environmental Science, Northwest Normal University, No. 967, Anning East Road, Lanzhou 730070, China; Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Northwest Normal University, Lanzhou 730070, China
| | - Qian Li
- College of Geography and Environmental Science, Northwest Normal University, No. 967, Anning East Road, Lanzhou 730070, China; Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Northwest Normal University, Lanzhou 730070, China
| | - Xuge Wang
- College of Geography and Environmental Science, Northwest Normal University, No. 967, Anning East Road, Lanzhou 730070, China; Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Northwest Normal University, Lanzhou 730070, China
| | - Changliang Qi
- College of Geography and Environmental Science, Northwest Normal University, No. 967, Anning East Road, Lanzhou 730070, China; Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Northwest Normal University, Lanzhou 730070, China
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Fan X, Hao X, Zhang S, Zhao Z, Zhang J, Li Y. Populus euphratica counteracts drought stress through the dew coupling and root hydraulic redistribution processes. ANNALS OF BOTANY 2023; 131:451-461. [PMID: 36624896 PMCID: PMC10072085 DOI: 10.1093/aob/mcac159] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND In arid and semi-arid areas, plants can directly absorb and use dew through their leaves, and some plants have the ability for hydraulic redistribution of their roots. Therefore, in arid areas, plants may redistribute dew to the soil, using the soil as a reservoir for short-term dry seasons, i.e. dew may participate in the hydraulic redistribution process of plants. This process plays an important role in plant survival and community stability. METHODS To verify this hypothesis, we investigated the water use mechanism of Populus euphratica through a comprehensive observation of sap flow, water potential and soil water content using a heavy water tracer experiment under in situ field conditions. RESULTS AND DISCUSSION Dewdrops contributed 28.3 % of soil moisture near the roots, and applying dew on leaves for several days significantly improved soil moisture status. Hydraulic redistribution in the roots mainly occurred from 2200 h at night to 800 h the following day and mainly occurred in the 20- to 80-cm soil layer. Water storage in the trunk is the intermediate link in the coupling process of foliar water uptake and hydraulic redistribution; water storage in the trunk is mainly replenished from May to July and consumed throughout the rest of the year. In conclusion, dew redistributes water into soil through the coupling process of foliar water uptake and hydraulic redistribution. Populus euphratica uses the trunk and soil for water storage to cope with water stress during short-term drought periods. Our findings provide a scientific basis for the restoration of different species in water-deficient areas, which is conducive to maintaining vegetation ecosystem stability in areas of desertification and improving the soil water balance.
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Affiliation(s)
- Xue Fan
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- Akesu National Station of Observation and Research for Oasis Agro-ecosystem, Akesu 843017, Xinjiang, China
| | - Xingming Hao
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- Akesu National Station of Observation and Research for Oasis Agro-ecosystem, Akesu 843017, Xinjiang, China
| | - Sen Zhang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- Akesu National Station of Observation and Research for Oasis Agro-ecosystem, Akesu 843017, Xinjiang, China
| | - Zhuoyi Zhao
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- Akesu National Station of Observation and Research for Oasis Agro-ecosystem, Akesu 843017, Xinjiang, China
| | - Jingjing Zhang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- Akesu National Station of Observation and Research for Oasis Agro-ecosystem, Akesu 843017, Xinjiang, China
| | - Yuanhang Li
- College of Life Sciences, Xinjiang Normal University, Urumqi 830054, China
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Johnson DM, Katul G, Domec J. Catastrophic hydraulic failure and tipping points in plants. PLANT, CELL & ENVIRONMENT 2022; 45:2231-2266. [PMID: 35394656 PMCID: PMC9544843 DOI: 10.1111/pce.14327] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/14/2022] [Accepted: 03/20/2022] [Indexed: 06/12/2023]
Abstract
Water inside plants forms a continuous chain from water in soils to the water evaporating from leaf surfaces. Failures in this chain result in reduced transpiration and photosynthesis and are caused by soil drying and/or cavitation-induced xylem embolism. Xylem embolism and plant hydraulic failure share several analogies to 'catastrophe theory' in dynamical systems. These catastrophes are often represented in the physiological and ecological literature as tipping points when control variables exogenous (e.g., soil water potential) or endogenous (e.g., leaf water potential) to the plant are allowed to vary on time scales much longer than time scales associated with cavitation events. Here, plant hydraulics viewed from the perspective of catastrophes at multiple spatial scales is considered with attention to bubble expansion within a xylem conduit, organ-scale vulnerability to embolism, and whole-plant biomass as a proxy for transpiration and hydraulic function. The hydraulic safety-efficiency tradeoff, hydraulic segmentation and maximum plant transpiration are examined using this framework. Underlying mechanisms for hydraulic failure at fine scales such as pit membranes and cell-wall mechanics, intermediate scales such as xylem network properties and at larger scales such as soil-tree hydraulic pathways are discussed. Understudied areas in plant hydraulics are also flagged where progress is urgently needed.
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Affiliation(s)
- Daniel M. Johnson
- Warnell School of Forestry and Natural ResourcesUniversity of GeorgiaAthensGeorgiaUSA
| | - Gabriel Katul
- Department of Civil and Environmental EngineeringDuke UniversityDurhamNorth CarolinaUSA
- Nicholas School of the EnvironmentDuke UniversityDurhamNorth CarolinaUSA
| | - Jean‐Christophe Domec
- Nicholas School of the EnvironmentDuke UniversityDurhamNorth CarolinaUSA
- Department of ForestryBordeaux Sciences Agro, UMR INRAE‐ISPA 1391GradignanFrance
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