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Mosquera GM, Marín F, Carabajo-Hidalgo A, Asbjornsen H, Célleri R, Crespo P. Ecohydrological assessment of the water balance of the world's highest elevation tropical forest (Polylepis). THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 941:173671. [PMID: 38825194 DOI: 10.1016/j.scitotenv.2024.173671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 05/15/2024] [Accepted: 05/29/2024] [Indexed: 06/04/2024]
Abstract
Polylepis trees grow at elevations above the continuous tree line (3000-5000 m a.s.l.) across the Andes. They tolerate extreme environmental conditions, making them sensitive bioindicators of global climate change. Therefore, investigating their ecohydrological role is key to understanding how the water cycle of Andean headwaters could be affected by predicted changes in environmental conditions, as well as ongoing Polylepis reforestation initiatives in the region. We estimate, for the first time, the annual water balance of a mature Polylepis forest (Polylepis reticulata) catchment (3780 m a.s.l.) located in the south Ecuadorian páramo using a unique set of field ecohydrological measurements including gross rainfall, throughfall, streamflow, and xylem sap flow in combination with the characterization of forest and soil features. We also compare the forest water balance with that of a tussock grass (Calamagrostis intermedia) catchment, the dominant páramo vegetation. Annual gross rainfall during the study period (April 2019-March 2020) was 1290.6 mm yr-1. Throughfall in the Polylepis forest represented 61.2 % of annual gross rainfall. Streamflow was the main component of the water balance of the forested site (59.6 %), while its change in soil water storage was negligible (<1 %). Forest evapotranspiration was 54.0 %, with evaporation from canopy interception (38.8 %) more than twice as high as transpiration (15.1 %). The error in the annual water balance of the Polylepis catchment was small (<15 %), providing confidence in the measurements and assumptions used to estimate its components. In comparison, streamflow and evapotranspiration at the grassland site accounted for 63.7 and 36.0 % of the water balance, respectively. Although evapotranspiration was larger in the forest catchment, its water yield was only marginally reduced (<4 %) in relation to the grassland catchment. The substantially higher soil organic matter content in the forest site (47.6 %) compared to the grassland site (31.8 %) suggests that even though Polylepis forests do not impair the hydrological function of high-Andean catchments, their presence contributes to carbon storage in the litter layer of the forest and the underlying soil. These findings provide key insights into the vegetation-water‑carbon nexus in high Andean ecosystems, which can serve as a basis for future ecohydrological studies and improved management of páramo natural resources considering changes in land use and global climate.
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Affiliation(s)
- Giovanny M Mosquera
- Departamento de Recursos Hídricos y Ciencias Ambientales (iDRHICA), Universidad de Cuenca, Cuenca, Ecuador; Departamento de Ingeniería & Grupo de Glaciología y Ecohidrología de Montañas Andinas (GEMS), Pontificia Universidad Católica del Perú (PUCP), Lima, Peru.
| | - Franklin Marín
- Facultad de Ciencias Agropecuarias, Carrera de Ingeniería Agronómica, Universidad de Cuenca, Cuenca, Ecuador; Laboratory of Quantitative Forest Ecosystem Science, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Belgium
| | - Aldemar Carabajo-Hidalgo
- Departamento de Recursos Hídricos y Ciencias Ambientales (iDRHICA), Universidad de Cuenca, Cuenca, Ecuador; Departamento de Biología Evolutiva, Ecología y Ciencias Ambientales, Universidad de Barcelona, Barcelona, Spain
| | - Heidi Asbjornsen
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA
| | - Rolando Célleri
- Departamento de Recursos Hídricos y Ciencias Ambientales (iDRHICA), Universidad de Cuenca, Cuenca, Ecuador; Facultad de Ingeniería, Universidad de Cuenca, Cuenca, Ecuador
| | - Patricio Crespo
- Departamento de Recursos Hídricos y Ciencias Ambientales (iDRHICA), Universidad de Cuenca, Cuenca, Ecuador; Facultad de Ingeniería, Universidad de Cuenca, Cuenca, Ecuador.
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Fradera-Soler M, Mravec J, Schulz A, Taboryski R, Jørgensen B, Grace OM. Revisiting an ecophysiological oddity: Hydathode-mediated foliar water uptake in Crassula species from southern Africa. PLANT, CELL & ENVIRONMENT 2024; 47:460-481. [PMID: 37876364 DOI: 10.1111/pce.14743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 10/10/2023] [Accepted: 10/16/2023] [Indexed: 10/26/2023]
Abstract
Hydathodes are usually associated with water exudation in plants. However, foliar water uptake (FWU) through the hydathodes has long been suspected in the leaf-succulent genus Crassula (Crassulaceae), a highly diverse group in southern Africa, and, to our knowledge, no empirical observations exist in the literature that unequivocally link FWU to hydathodes in this genus. FWU is expected to be particularly beneficial on the arid western side of southern Africa, where up to 50% of Crassula species occur and where periodically high air humidity leads to fog and/or dew formation. To investigate if hydathode-mediated FWU is operational in different Crassula species, we used the apoplastic fluorescent tracer Lucifer Yellow in combination with different imaging techniques. Our images of dye-treated leaves confirm that hydathode-mediated FWU does indeed occur in Crassula and that it might be widespread across the genus. Hydathodes in Crassula serve as moisture-harvesting structures, besides their more common purpose of guttation, an adaptation that has likely played an important role in the evolutionary history of the genus. Our observations suggest that ability for FWU is independent of geographical distribution and not restricted to arid environments under fog influence, as FWU is also operational in Crassula species from the rather humid eastern side of southern Africa. Our observations point towards no apparent link between FWU ability and overall leaf surface wettability in Crassula. Instead, the hierarchically sculptured leaf surfaces of several Crassula species may facilitate FWU due to hydrophilic leaf surface microdomains, even in seemingly hydrophobic species. Overall, these results confirm the ecophysiological relevance of hydathode-mediated FWU in Crassula and reassert the importance of atmospheric humidity for some arid-adapted plant groups.
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Affiliation(s)
- Marc Fradera-Soler
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- Royal Botanic Gardens, Kew, Richmond, Surrey, UK
| | - Jozef Mravec
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences, Plant Science and Biodiversity Center, Nitra, Slovakia
| | - Alexander Schulz
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Rafael Taboryski
- National Centre for Nano Fabrication and Characterization (DTU Nanolab), Technical University of Denmark, Lyngby, Denmark
| | - Bodil Jørgensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Olwen M Grace
- Royal Botanic Gardens, Kew, Richmond, Surrey, UK
- Royal Botanic Garden Edinburgh, Edinburgh, UK
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Liu F, Liu H, Adalibieke W, Peng Z, Liang B, Feng S, Shi L, Zhu X. Decline in stability of forest productivity in the tropics as determined by canopy water content. iScience 2023; 26:107211. [PMID: 37456836 PMCID: PMC10339190 DOI: 10.1016/j.isci.2023.107211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 05/19/2023] [Accepted: 06/22/2023] [Indexed: 07/18/2023] Open
Abstract
The impacts of low soil moisture (SM) and high vapour pressure deficit (VPD) on tree's photosynthesis and productivity are ultimately realized by changing water content in the canopy leaves. In this study, variations in canopy water content (CWC) that can be detected from microwave remotely sensed vegetation optical depth (VOD) have been proposed as a promising measure of vegetation water status, and we first reported that the regulation of CWC on productivity stability is universally applicable for global forests. Results of structural equation model (SEM) also confirmed the significant negative effect of CWC on coefficient of variation (CV) of productivity, indicating that the decrease in CWC could inevitably induce the instability of forest productivity under climate change. The most significant decrease (p < 0.01) of CWC is observed primarily in evergreen broadleaf forest in the tropics, implying an increasing instability of the most important carbon sink in terrestrial ecosystem.
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Affiliation(s)
- Feng Liu
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China
| | - Hongyan Liu
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China
| | - Wulahati Adalibieke
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China
| | - Zhaoyu Peng
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China
| | - Boyi Liang
- College of Forestry, Precision Forestry Key Laboratory of Beijing, Beijing Forestry University, Beijing 100083, China
| | - Siwen Feng
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China
| | - Liang Shi
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China
| | - Xinrong Zhu
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, 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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Lima JF, Boanares D, Costa VE, Moreira ASFP. Do photosynthetic metabolism and habitat influence foliar water uptake in orchids? PLANT BIOLOGY (STUTTGART, GERMANY) 2023; 25:257-267. [PMID: 36546714 DOI: 10.1111/plb.13499] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 12/11/2022] [Indexed: 06/17/2023]
Abstract
Epiphytic and rupicolous plants inhabit environments with limited water resources. Such plants commonly use Crassulacean Acid Metabolism (CAM), a photosynthetic pathway that accumulates organic acids in cell vacuoles at night, so reducing their leaf water potential and favouring water absorption. Foliar water uptake (FWU) aids plant survival during drought events in environments with high water deficits. We hypothesized that FWU represents a strategy employed by epiphytic and rupicolous orchids for water acquisition and that CAM will favour increased water absorption. We examined 6 epiphyte, 4 terrestrial and 6 rupicolous orchids that use C3 (n = 9) or CAM (n = 7) pathways. Five individuals per species were used to evaluate FWU, structural characteristics and leaf water balance. Rupicolous species with C3 metabolism had higher FWU than other species. FWU (Cmax and k) could be related to succulence, SLM and leaf RWC. The results indicated that high orchid leaf densities favoured FWU, as area available for water storage increases with leaf density. Structural characteristics linked to water storage (e.g. high RWC, succulence), on the other hand, could limit leaf water absorption by favouring high internal leaf water potentials. Epiphytic, rupicolous and terrestrial orchids showed FWU. Rupicolous species had high levels of FWU, probably through absorption from mist. However, succulence in plants with CAM appears to mitigate FWU.
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Affiliation(s)
- J F Lima
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Brazil
| | - D Boanares
- Instituto Tecnológico Vale, Desenvolvimento Sustentável, Belém, Brazil
| | - V E Costa
- Instituto de Biociências, Centro de Isótopos Estáveis Prof. Dr. Carlos Ducatti, Botucatu, Brazil
| | - A S F P Moreira
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Brazil
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Kagawa A. Foliar water uptake as a source of hydrogen and oxygen in plant biomass. TREE PHYSIOLOGY 2022; 42:2153-2173. [PMID: 35554604 PMCID: PMC9652008 DOI: 10.1093/treephys/tpac055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/08/2022] [Indexed: 05/11/2023]
Abstract
Introductory biology lessons around the world typically teach that plants absorb water through their roots, but, unfortunately, absorption of water through leaves and subsequent transport and use of this water for biomass formation remains a field limited mostly to specialists. Recent studies have identified foliar water uptake as a significant net water source for terrestrial plants. The growing interest in the development of a new model that includes both foliar water uptake (in liquid form) and root water uptake to explain hydrogen and oxygen isotope ratios in leaf water and tree rings demands a method for distinguishing between these two water sources. Therefore, in this study, I have devised a new labelling method that utilizes two different water sources, one enriched in deuterium (HDO + D2O; δD = 7.0 × 10 4‰, δ18O = 4.1‰) and one enriched in oxygen-18 (H218O; δD = -85‰, δ18O = 1.1 × 104‰), to simultaneously label both foliar-absorbed and root-absorbed water and quantify their relative contributions to plant biomass. Using this new method, I here present evidence that, in the case of well-watered Cryptomeria japonica D. Don, hydrogen and oxygen incorporated into new leaf cellulose in the rainy season derives mostly from foliar-absorbed water (69% from foliar-absorbed water and 31% from root-absorbed water), while that of new root cellulose derives mostly from root-absorbed water (20% from foliar-absorbed water and 80% from root-absorbed water), and new branch xylem is somewhere in between (55% from foliar-absorbed water and 45% from root-absorbed water). The dual-labelling method first implemented in this study enables separate and simultaneous labelling of foliar-absorbed and root-absorbed water and offers a new tool to study the uptake, transport and assimilation processes of these waters in terrestrial plants.
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da Rosa Ferraz Jardim AM, de Morais JEF, de Souza LSB, da Silva TGF. Understanding interactive processes: a review of CO 2 flux, evapotranspiration, and energy partitioning under stressful conditions in dry forest and agricultural environments. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:677. [PMID: 35974211 DOI: 10.1007/s10661-022-10339-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/06/2022] [Indexed: 06/15/2023]
Abstract
Arid and semiarid environments are characterized by low water availability (e.g., in soil and atmosphere), high air temperature, and irregularity in the spatio-temporal distribution of rainfall. In addition to the economic and environmental consequences, drought also causes physiological damage to crops and compromises their survival in ecosystems. The removal of vegetation is responsible for altering the energy exchange of heat and water in natural ecosystems and agricultural areas. The fluxes of CO2 are also changed, and environments with characteristics of sinks, which can be sources of CO2 after anthropic disturbances. These changes can be measured through methods such as sap flow, eddy covariance, remote sensing, and energy balance. Despite the relevance of each method mentioned above, there are limitations in their applications that must be respected. Thus, this review aims to quantify the processes and changes of energy fluxes, CO2, and their interactions with the surfaces of terrestrial ecosystems in dry environments. Studies report that the use of methods that integrate data from climate monitoring towers and remote sensing products helps to improve the accuracy of the determination of energy fluxes on a global scale, also helping to reduce the dissimilarity of results obtained individually. Through the collection of works in the literature, it is reported that several areas of the Brazilian Caatinga biome, which is a Seasonally Dry Tropical Forest have been suffering from changes in land use and land cover. Similar fluxes of sensible heat in areas with cacti and Caatinga can be observed in studies. On the other hand, one of the variables influenced mainly by air temperature is net radiation. In dry forest areas, woody species can store large amounts of carbon in their biomass above and belowground. The use of cacti can modify the local carbon budget when using tree crops together. Therefore, the study highlights the complexity and severity of land degradation and changes in CO2, water, and energy fluxes in dry environments with areas of forest, grassland, and cacti. Vegetation energy balance is also a critical factor, as these simulations are helpful for use in forecasting weather or climate change. We also highlight the need for more studies that address environmental conservation techniques and cactus in the conservation of degraded areas.
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Affiliation(s)
- Alexandre Maniçoba da Rosa Ferraz Jardim
- Department of Agricultural Engineering, Federal Rural University of Pernambuco, Dom Manoel de Medeiros avenue, s/n, Dois Irmãos, Recife, Pernambuco, 52171-900, Brazil.
- Academic Unit of Serra Talhada, Federal Rural University of Pernambuco, Gregório Ferraz Nogueira avenue, s/n, Serra Talhada, Pernambuco, 56909-535, Brazil.
| | - José Edson Florentino de Morais
- Academic Unit of Serra Talhada, Federal Rural University of Pernambuco, Gregório Ferraz Nogueira avenue, s/n, Serra Talhada, Pernambuco, 56909-535, Brazil
| | - Luciana Sandra Bastos de Souza
- Academic Unit of Serra Talhada, Federal Rural University of Pernambuco, Gregório Ferraz Nogueira avenue, s/n, Serra Talhada, Pernambuco, 56909-535, Brazil
| | - Thieres George Freire da Silva
- Academic Unit of Serra Talhada, Federal Rural University of Pernambuco, Gregório Ferraz Nogueira avenue, s/n, Serra Talhada, Pernambuco, 56909-535, Brazil
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Abstract
Foliar water uptake (FWU) is a mechanism that enables plants to acquire water from the atmosphere through their leaves. As mangroves live in a saline sediment water environment, the mechanism of FWU might be of vital importance to acquire freshwater and grow. The goal of this study was to assess the FWU capacity of six different mangrove species belonging to four genera using a series of submersion experiments in which the leaf mass increase was measured and expressed per unit leaf area. The foliar water uptake capacity differed between species with the highest and lowest average water uptake in Avicennia marina (Forssk.) Vierh. (1.52 ± 0.48 mg H2O cm−2) and Bruguiera gymnorhiza (L.) Lam. (0.13 ± 0.06 mg H2O cm−2), respectively. Salt-excreting species showed a higher FWU capacity than non-excreting species. Moreover, A. marina, a salt-excreting species, showed a distinct leaf anatomical trait, i.e., trichomes, which were not observed in the other species and might be involved in the water absorption process. The storage of leaves in moist Ziplock bags prior to measurement caused leaf water uptake to already occur during transport to the field station, which proportionately increased the leaf water potential (A. marina: −0.31 ± 0.13 MPa and B. gymnorhiza: −2.70 ± 0.27 MPa). This increase should be considered when performing best practice leaf water potential measurements but did not affect the quantification of FWU capacity because of the water potential gradient between a leaf and the surrounding water during submersion. Our results highlight the differences that exist in FWU capacity between species residing in the same area and growing under the same environmental conditions. This comparative study therefore enhances our understanding of mangrove species’ functioning.
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Williams CB, Reese Næsborg R, Ambrose AR, Baxter WL, Koch GW, Dawson TE. The dynamics of stem water storage in the tops of Earth's largest trees-Sequoiadendron giganteum. TREE PHYSIOLOGY 2021; 41:2262-2278. [PMID: 34104960 DOI: 10.1093/treephys/tpab078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 05/31/2021] [Indexed: 06/12/2023]
Abstract
Water stored in tree stems (i.e., trunks and branches) is an important contributor to transpiration that can improve photosynthetic carbon gain and reduce the probability of cavitation. However, in tall trees, the capacity to store water may decline with height because of chronically low water potentials associated with the gravitational potential gradient. We quantified the importance of elastic stem water storage in the top 5-6 m of large (4.2-5.0 m diameter at breast height, 82.1-86.3 m tall) Sequoiadendron giganteum (Lindley) J. Buchholz (giant sequoia) trees using a combination of architectural measurements and automated sensors that monitored summertime diel rhythms in sap flow, stem diameter and water potential. Stem water storage contributed 1.5-1.8% of water transpired at the tree tops, and hydraulic capacitance ranged from 2.6 to 4.1 l MPa-1 m-3. These values, which are considerably smaller than reported for shorter trees, may be associated with persistently low water potentials imposed by gravity and could indicate a trend of decreasing water storage dynamics with height in tree. Branch diameter contraction and expansion consistently and substantially lagged behind fluxes in water potential and sap flow, which occurred in sync. This lag suggests that the inner bark, which consists mostly of live secondary phloem tissue, was an important hydraulic capacitor, and that hydraulic resistance between xylem and phloem retards water transfer between these tissues. We also measured tree-base sap flux, which lagged behind that measured in trunks near the tree tops, indicating additional storage in the large trunks between these measurement positions. Whole-tree sap flow ranged from 2227 to 3752 l day-1, corroborating previous records for similar-sized giant sequoia and representing the largest yet reported for any individual tree. Despite such extraordinarily high daily water use, we estimate that water stored in tree-top stems contributes minimally to transpiration on typical summer days.
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Affiliation(s)
- Cameron B Williams
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
- Channel Islands National Park, Ventura, CA 93001, USA
- Santa Barbara Botanic Garden, Santa Barbara, CA 93105, USA
| | - Rikke Reese Næsborg
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
- Santa Barbara Botanic Garden, Santa Barbara, CA 93105, USA
| | - Anthony R Ambrose
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
- The Marmot Society, South Lake Tahoe, CA 96150, USA
| | - Wendy L Baxter
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
- The Marmot Society, South Lake Tahoe, CA 96150, USA
| | - George W Koch
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Todd E Dawson
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
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Moreno-Fernández D, Viana-Soto A, Camarero JJ, Zavala MA, Tijerín J, García M. Using spectral indices as early warning signals of forest dieback: The case of drought-prone Pinus pinaster forests. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 793:148578. [PMID: 34174606 DOI: 10.1016/j.scitotenv.2021.148578] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
Forest dieback processes linked to drought are expected to increase due to climate warming. Remotely sensed data offer several advantages over common field monitoring methods such as the ability to observe large areas on a systematic basis and monitoring their changes, making them increasingly used to assess changes in forest health. Here we aim to use a combined approximation of fieldwork and remote sensing to explore possible links between forest dieback and land surface phenological and trend variables derived from long Landsat time series. Forest dieback was evaluated in the field over 31 plots in a Mediterranean, xeric Pinus pinaster forest. Landsat 31-year time series of three greenness (EVI, NDVI, SAVI) and two wetness spectral indices (NMDI and TCW) were derived covering the period 1990-2020. Spectral indices from time series were decomposed into trend and seasonality using a Bayesian estimator while the relationships of the phenological and trend variables among levels of damage were assessed using linear and additive mixed models. We have not found any statistical pieces of evidence of extension or shortening patterns for the length of the phenological season over the examined 31-year period. Our results indicate that the dieback process was mainly related to the trend component of the spectral indices series whereas the phenological metrics were not related to forest dieback. We also found that plots with more dying or damaged trees displayed lower spectral indices trends after a severe drought event in the middle of the 1990s, which confirms the Landsat-derived spectral indices as indicators of early-warning signals. Drops in trends occurred earlier for wetness indices rather than for greenness indices which suggests that the former could be more appropriate for dieback detection, i.e. they could be used as early warning signals of impending loss of tree vigor.
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Affiliation(s)
- Daniel Moreno-Fernández
- Universidad de Alcalá, Departamento de Ciencias de la Vida, Forest Ecology and Restoration Group, Edificio Ciencias, Campus Universitario, 28871 Alcalá de Henares, Madrid, Spain.
| | - Alba Viana-Soto
- Universidad de Alcalá, Departamento de Geología, Geografía y Medio Ambiente, Environmental Remote Sensing Research Group. Calle Colegios 2, 28801 Alcalá de Henares, Spain
| | - Julio Jesús Camarero
- Instituto Pirenaico de Ecología (IPE-CSIC), Avda. Montañana 1005, E-50192 Zaragoza, Spain
| | - Miguel A Zavala
- Universidad de Alcalá, Departamento de Ciencias de la Vida, Forest Ecology and Restoration Group, Edificio Ciencias, Campus Universitario, 28871 Alcalá de Henares, Madrid, Spain
| | - Julián Tijerín
- Universidad de Alcalá, Departamento de Ciencias de la Vida, Forest Ecology and Restoration Group, Edificio Ciencias, Campus Universitario, 28871 Alcalá de Henares, Madrid, Spain
| | - Mariano García
- Universidad de Alcalá, Departamento de Geología, Geografía y Medio Ambiente, Environmental Remote Sensing Research Group. Calle Colegios 2, 28801 Alcalá de Henares, Spain
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11
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Boanares D, Bueno A, de Souza AX, Kozovits AR, Sousa HC, Pimenta LPS, Isaias RMDS, França MGC. Cuticular wax composition contributes to different strategies of foliar water uptake in six plant species from foggy rupestrian grassland in tropical mountains. PHYTOCHEMISTRY 2021; 190:112894. [PMID: 34364088 DOI: 10.1016/j.phytochem.2021.112894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/21/2021] [Accepted: 07/31/2021] [Indexed: 06/13/2023]
Abstract
The cuticle is the outermost region of the epidermal cell wall of plant aerial organs. The cuticle acts as a two-way lipid barrier for water diffusion; therefore, it plays a vital role in foliar water uptake (FWU). We hypothesised that the chemical composition of the cuticular waxes influences the FWU strategy that plants adopt in a foggy tropical ecosystem. We analysed the leaf cuticular waxes of six plant species known by their different FWU strategies, in both qualitative and quantitative approaches, to test this hypothesis. We also investigated the fine structure of the plant cuticle by scanning electron microscopy. Neither the total wax loads nor the amounts of single wax compound classes correlated to the FWU. In contrast, the qualitative chemical composition of the cuticular waxes was related to the water absorption speed but not to the maximum water absorbed. The presence of wax crystals might interfere with the FWU. Our findings suggest that a complex three-dimensional network of the cuticular compounds contributes to different strategies of FWU in six plant species from foggy tropical mountaintops.
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Affiliation(s)
- Daniela Boanares
- Departamento de Botânica, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
| | - Amauri Bueno
- University of Würzburg, Julius-von-Sachs Institute of Biological Sciences, Chair of Botany II - Ecophysiology and Vegetation Ecology, Würzburg, Germany.
| | - Aline Xavier de Souza
- University of Würzburg, Julius-von-Sachs Institute of Biological Sciences, Chair of Botany II - Ecophysiology and Vegetation Ecology, Würzburg, Germany
| | | | - Hildeberto Caldas Sousa
- Departamento de Biodiversidade, Evolução e Meio Ambiente, Universidade Federal de Ouro Preto, Minas Gerais, Brazil
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12
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Coopman RE, Nguyen HT, Mencuccini M, Oliveira RS, Sack L, Lovelock CE, Ball MC. Harvesting water from unsaturated atmospheres: deliquescence of salt secreted onto leaf surfaces drives reverse sap flow in a dominant arid climate mangrove, Avicennia marina. THE NEW PHYTOLOGIST 2021; 231:1401-1414. [PMID: 33983649 DOI: 10.1111/nph.17461] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 03/25/2021] [Indexed: 06/12/2023]
Abstract
The mangrove Avicennia marina adjusts internal salt concentrations by foliar salt secretion. Deliquescence of accumulated salt causes leaf wetting that may provide a water source for salt-secreting plants in arid coastal wetlands where high nocturnal humidity can usually support deliquescence whereas rainfall events are rare. We tested the hypotheses that salt deliquescence on leaf surfaces can drive top-down rehydration, and that such absorption of moisture from unsaturated atmospheres makes a functional contribution to dry season shoot water balances. Sap flow and water relations were monitored to assess the uptake of atmospheric water by branches during shoot wetting events under natural and manipulated microclimatic conditions. Reverse sap flow rates increased with increasing relative humidity from 70% to 89%, consistent with function of salt deliquescence in harvesting moisture from unsaturated atmospheres. Top-down rehydration elevated branch water potentials above those possible from root water uptake, subsidising transpiration rates and reducing branch vulnerability to hydraulic failure in the subsequent photoperiod. Absorption of atmospheric moisture harvested through deliquescence of salt on leaf surfaces enhances water balances of Avicennia marina growing in hypersaline wetlands under arid climatic conditions. Top-down rehydration from these frequent, low intensity wetting events contributes to prevention of carbon starvation and hydraulic failure during drought.
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Affiliation(s)
- Rafael E Coopman
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
- Ecophysiology Laboratory for Forest Conservation, Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Campus Isla Teja, Casilla 567, Valdivia, Chile
| | - Hoa T Nguyen
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
- Department of Botany, Faculty of Agronomy, Vietnam National University of Agriculture, Trau Quy, Gia Lam, Hanoi, 131000, Vietnam
| | - Maurizio Mencuccini
- CREAF, Universidad Autonoma de Barcelona, Cerdanyola del Valles 08193, Barcelona, Spain
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, Campinas, São Paulo, CP6109, Brazil
| | - Lawren Sack
- Department of Ecology and Evolution, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Catherine E Lovelock
- School of Biological Sciences, The University of Queensland, St Lucia, Qld, 4072, Australia
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
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13
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Liu F, Liu H, Xu C, Shi L, Zhu X, Qi Y, He W. Old-growth forests show low canopy resilience to droughts at the southern edge of the taiga. GLOBAL CHANGE BIOLOGY 2021; 27:2392-2402. [PMID: 33740267 DOI: 10.1111/gcb.15605] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/22/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
Forest mortality and resilience driven by drought disturbances have attracted tons of attention. However, the acquisition of continuous spatial-temporal data is generally enslaved to the conventional field investigations. In this study, the resilience of semiarid forest was characterized with canopy dynamics from remote sensing observations, combining the variations in canopy greenness and water content. We integrated dense normalized difference vegetation index (NDVI) and normalized difference infrared index (NDII) time series from Landsat datasets, intending to assess the canopy resilience in 24 conifer patches along a climatic aridity gradient at the southern edge of the taiga in northern Mongolia and southern Siberia of Russia. The results exhibited four patterns of coordinated NDVI-NDII variation trends, indicating that the canopy water content of coniferous forests may decrease at first during a drought period, and sustained water loss may, in turn, induce an accompanying reduction in canopy greenness. Meanwhile, the patches with canopy recovery growth after initial declines were considered to have resilience to climate change. We further observed the combined effects of aridity degree and tree age on canopy resilience, and all seven patches with no resilience corresponded to the old-tree group (the oldest trees reached or exceeded the age of 90). The observations indicated that the old-growth forests in semiarid regions were less likely to show canopy resilience, which corresponded to a higher risk of sustained decline.
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Affiliation(s)
- Feng Liu
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing, China
| | - Hongyan Liu
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing, China
| | - Chongyang Xu
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing, China
| | - Liang Shi
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing, China
| | - Xinrong Zhu
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing, China
| | - Yang Qi
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing, China
| | - Wenqi He
- College of Urban and Environmental Sciences and MOE Laboratory for Earth Surface Processes, Peking University, Beijing, China
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14
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Li X, Zhang C, Zhang B, Wu D, Zhu D, Zhang W, Ye Q, Yan J, Fu J, Fang C, Ha D, Fu S. Nitrogen deposition and increased precipitation interact to affect fine root production and biomass in a temperate forest: Implications for carbon cycling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 765:144497. [PMID: 33418324 DOI: 10.1016/j.scitotenv.2020.144497] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 12/06/2020] [Accepted: 12/09/2020] [Indexed: 06/12/2023]
Abstract
Fine roots connect belowground and aboveground systems and help regulate the carbon balance of terrestrial ecosystems by providing nutrients and water for plants. To evaluate the effects of atmospheric nitrogen (N) deposition and increased precipitation on fine root production and standing biomass in a temperate deciduous forest in central China, we conducted a 6-year experiment. From 2013 to 2018, we applied N (25 kg N ha-1 yr-1) and water (336 mm, 30% of the ambient annual precipitation) above the forest canopy, and we quantified fine root production and biomass in 2017 and 2018. At 0-10 cm soil depth, the statistical interaction between addition of N and water was not significant in terms of fine root production or biomass. At 0-10 cm soil depth, N addition significantly increased fine root production by 18.1%, but did not affect fine root biomass. Water addition significantly increased fine root production and biomass by 13.6 and 17.0%, respectively. Both N and water addition had significant direct positive effects on fine root production, and water addition had indirect positive effects on fine root biomass through decreasing soil NO3- concentration. At 10-30 cm soil depth, the statistical interaction between N addition and water addition was significant in terms of both fine root production and biomass, i.e., the positive effect of N addition was reduced by water addition, and vice versa. These findings indicate that fine roots and therefore belowground carbon storage may have complex responses to increases in atmospheric N deposition and changes in precipitation predicted for the future. The findings also suggest that results obtained from experiments that consider only one independent variable (e.g., N input or water input) and only one soil depth should be interpreted with caution.
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Affiliation(s)
- Xiaowei Li
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China; Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security, Henan University, Kaifeng 475004, China
| | - Chenlu Zhang
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China; Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security, Henan University, Kaifeng 475004, China.
| | - Beibei Zhang
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China
| | - Di Wu
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China
| | - Dandan Zhu
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China
| | - Wei Zhang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Junhua Yan
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Juemin Fu
- Jigongshan National Nature Reserve, Xinyang 464039, China
| | | | - Denglong Ha
- Jigongshan National Nature Reserve, Xinyang 464039, China
| | - Shenglei Fu
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China; Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security, Henan University, Kaifeng 475004, China
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15
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Schreel JDM, Steppe K. Foliar Water Uptake in Trees: Negligible or Necessary? TRENDS IN PLANT SCIENCE 2020; 25:590-603. [PMID: 32407698 DOI: 10.1016/j.tplants.2020.01.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 01/06/2020] [Accepted: 01/15/2020] [Indexed: 06/11/2023]
Abstract
Foliar water uptake (FWU) has been identified as a mechanism commonly used by trees and other plants originating from various biomes. However, many questions regarding the pathways and the implications of FWU remain, including its ability to mitigate climate change-driven drought. Therefore, answering these questions is of primary importance to adequately address and comprehend drought stress responses and associated growth. In this review, we discuss the occurrence, pathways, and consequences of FWU, with a focus predominantly on tree species. Subsequently, we highlight the tight coupling between FWU and foliar fertilizer applications, discuss FWU in a changing climate, and conclude with the importance of including FWU in mechanistic vegetation models.
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Affiliation(s)
- Jeroen D M Schreel
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium.
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium.
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16
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Lehmann MM, Goldsmith GR, Mirande-Ney C, Weigt RB, Schönbeck L, Kahmen A, Gessler A, Siegwolf RTW, Saurer M. The 18 O-signal transfer from water vapour to leaf water and assimilates varies among plant species and growth forms. PLANT, CELL & ENVIRONMENT 2020; 43:510-523. [PMID: 31732962 DOI: 10.1111/pce.13682] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 11/11/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
The 18 O signature of atmospheric water vapour (δ18 OV ) is known to be transferred via leaf water to assimilates. It remains, however, unclear how the 18 O-signal transfer differs among plant species and growth forms. We performed a 9-hr greenhouse fog experiment (relative humidity ≥ 98%) with 18 O-depleted water vapour (-106.7‰) on 140 plant species of eight different growth forms during daytime. We quantified the 18 O-signal transfer by calculating the mean residence time of O in leaf water (MRTLW ) and sugars (MRTSugars ) and related it to leaf traits and physiological drivers. MRTLW increased with leaf succulence and thickness, varying between 1.4 and 10.8 hr. MRTSugars was shorter in C3 and C4 plants than in crassulacean acid metabolism (CAM) plants and highly variable among species and growth forms; MRTSugars was shortest for grasses and aquatic plants, intermediate for broadleaf trees, shrubs, and herbs, and longest for conifers, epiphytes, and succulents. Sucrose was more sensitive to δ18 OV variations than other assimilates. Our comprehensive study shows that plant species and growth forms vary strongly in their sensitivity to δ18 OV variations, which is important for the interpretation of δ18 O values in plant organic material and compounds and thus for the reconstruction of climatic conditions and plant functional responses.
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Affiliation(s)
- Marco M Lehmann
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, 8903, Switzerland
| | - Gregory R Goldsmith
- Schmid College of Science and Technology, Chapman University, Orange, CA, 92866
| | | | - Rosemarie B Weigt
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, 8903, Switzerland
| | - Leonie Schönbeck
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, 8903, Switzerland
| | - Ansgar Kahmen
- Department of Environmental Sciences-Botany, University of Basel, Basel, 4056, Switzerland
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, 8903, Switzerland
| | - Rolf T W Siegwolf
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, 8903, Switzerland
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, 8903, Switzerland
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17
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Schreel JDM, Van de Wal BAE, Hervé-Fernandez P, Boeckx P, Steppe K. Hydraulic redistribution of foliar absorbed water causes turgor-driven growth in mangrove seedlings. PLANT, CELL & ENVIRONMENT 2019; 42:2437-2447. [PMID: 30953380 DOI: 10.1111/pce.13556] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 03/25/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
Although foliar water uptake (FWU) has been shown in mature Avicennia marina trees, the importance for its seedlings remains largely unknown. A series of experiments were therefore performed using artificial rainfall events in a greenhouse environment to assess the ecological implications of FWU in A. marina seedlings. One-hour artificial rainfall events resulted in an increased leaf water potential, a reversed sap flow, and a rapid diameter increment signifying a turgor-driven growth of up to 30.1 ± 5.4 μm. Furthermore, the application of an artificial rainfall event with deuterated water showed that the amount of water absorbed by the leaves and transported to the stem was directly and univocally correlated to the observed growth spurts. The observations in this process-based study show that FWU is an important water acquisition mechanism under certain circumstances and might be of ecological importance for the establishment of A. marina seedlings. Distribution of mangrove trees might hence be more significantly disturbed by climate change-driven changes in rainfall patterns than previously assumed.
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Affiliation(s)
- Jeroen D M Schreel
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
| | - Bart A E Van de Wal
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
| | - Pedro Hervé-Fernandez
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
- Isotope Bioscience Laboratory (ISOFYS), Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
| | - Pascal Boeckx
- Isotope Bioscience Laboratory (ISOFYS), Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
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18
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Binks O, Mencuccini M, Rowland L, da Costa ACL, de Carvalho CJR, Bittencourt P, Eller C, Teodoro GS, Carvalho EJM, Soza A, Ferreira L, Vasconcelos SS, Oliveira R, Meir P. Foliar water uptake in Amazonian trees: Evidence and consequences. GLOBAL CHANGE BIOLOGY 2019; 25:2678-2690. [PMID: 31012521 DOI: 10.1111/gcb.14666] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 04/05/2019] [Accepted: 04/12/2019] [Indexed: 06/09/2023]
Abstract
The absorption of atmospheric water directly into leaves enables plants to alleviate the water stress caused by low soil moisture, hydraulic resistance in the xylem and the effect of gravity on the water column, while enabling plants to scavenge small inputs of water from leaf-wetting events. By increasing the availability of water, and supplying it from the top of the canopy (in a direction facilitated by gravity), foliar uptake (FU) may be a significant process in determining how forests interact with climate, and could alter our interpretation of current metrics for hydraulic stress and sensitivity. FU has not been reported for lowland tropical rainforests; we test whether FU occurs in six common Amazonian tree genera in lowland Amazônia, and make a first estimation of its contribution to canopy-atmosphere water exchange. We demonstrate that FU occurs in all six genera and that dew-derived water may therefore be used to "pay" for some morning transpiration in the dry season. Using meteorological and canopy wetness data, coupled with empirically derived estimates of leaf conductance to FU (kfu ), we estimate that the contribution by FU to annual transpiration at this site has a median value of 8.2% (103 mm/year) and an interquartile range of 3.4%-15.3%, with the biggest sources of uncertainty being kfu and the proportion of time the canopy is wet. Our results indicate that FU is likely to be a common strategy and may have significant implications for the Amazon carbon budget. The process of foliar water uptake may also have a profound impact on the drought tolerance of individual Amazonian trees and tree species, and on the cycling of water and carbon, regionally and globally.
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Affiliation(s)
- Oliver Binks
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | | | - Lucy Rowland
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | | | - Paulo Bittencourt
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Cleiton Eller
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | | | - Azul Soza
- Department of Plant Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | | | | | - Rafael Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Patrick Meir
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- School of Geosciences, University of Edinburgh, Edinburgh, UK
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19
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Abstract
Bamboo water transport comprises the pathway rhizomes-culms-leaves as well as transfer among culms via connected rhizomes. We assessed bamboo water transport in three big clumpy bamboo species by deuterium tracing. The tracer was injected into the base of established culms, and water samples were collected from leaves of the labeled culms and from neighboring culms. From the base of labeled culms to their leaves, the average tracer arrival time across species was 1.2 days, maximum tracer concentration was reached after 1.8 days, and the tracer residence time was 5.6 days. Sap velocities were high (13.9 m d−1). Daily culm water use rates estimated by the tracer method versus rates measured by a calibrated sap flux method were highly correlated (R2 = 0.94), but the tracer estimates were about 70% higher. Elevated deuterium concentrations in studied neighbor culms point to deuterium transfer among culms, which may explain the difference in culm water use estimates. We found no differences in deuterium concentrations between neighbor-established and neighbor freshly sprouted culms of a given species. In two species, elevated concentrations in both neighbor-established and neighbor freshly sprouted culms were observed over an extended period. An applied mixing model suggests that five neighbor culms received labeled water. In contrast, for the third species, elevated concentrations in neighbor culms were only observed at the earliest sampling date after labeling. This could indicate that there was only short-term transfer and that the tracer was distributed more widely across the rhizome network. In conclusion, our deuterium tracing experiments point to water transfer among culms, but with species-specific differences.
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20
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Influence of Drought on Foliar Water Uptake Capacity of Temperate Tree Species. FORESTS 2019. [DOI: 10.3390/f10070562] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Foliar water uptake (FWU) has been investigated in an increasing number of species from a variety of areas but has remained largely understudied in deciduous, temperate tree species from non-foggy regions. As leaf wetting events frequently occur in temperate regions, FWU might be more important than previously thought and should be investigated. As climate change progresses, the number of drought events is expected to increase, basically resulting in a decreasing number of leaf wetting events, which might make FWU a seemingly less important mechanism. However, the impact of drought on FWU might not be that unidirectional because drought will also cause a more negative tree water potential, which is expected to result in more FWU. It yet remains unclear whether drought results in a general increase or decrease in the amount of water absorbed by leaves. The main objectives of this study are, therefore: (i) to assess FWU-capacity in nine widely distributed key tree species from temperate regions, and (ii) to investigate the effect of drought on FWU in these species. Based on measurements of leaf and soil water potential and FWU-capacity, the effect of drought on FWU in temperate tree species was assessed. Eight out of nine temperate tree species were able to absorb water via their leaves. The amount of water absorbed by leaves and the response of this plant trait to drought were species-dependent, with a general increase in the amount of water absorbed as leaf water potential decreased. This relationship was less pronounced when using soil water potential as an independent variable. We were able to classify species according to their response in FWU to drought at the leaf level, but this classification changed when using drought at the soil level, and was driven by iso- and anisohydric behavior. FWU hence occurred in several key tree species from temperate regions, be it with some variability, which potentially allows these species to partly reduce the effects of drought stress. We recommend including this mechanism in future research regarding plant–water relations and to investigate the impact of different pathways used for FWU.
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21
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Boanares D, Kozovits AR, Lemos-Filho JP, Isaias RMS, Solar RRR, Duarte AA, Vilas-Boas T, França MGC. Foliar water-uptake strategies are related to leaf water status and gas exchange in plants from a ferruginous rupestrian field. AMERICAN JOURNAL OF BOTANY 2019; 106:935-942. [PMID: 31281976 DOI: 10.1002/ajb2.1322] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 05/03/2019] [Indexed: 06/09/2023]
Abstract
PREMISE Fog is a frequent event in Brazilian rupestrian field and plays an important role in the physiology of several plant species. Foliar water uptake (FWU) of fog may be fast or slow depending on the species. However, fog water may negatively affect CO2 assimilation. Thus, the interference in the water and carbon balance as a result of different strategies of FWU was evaluated to verify whether fog may mitigate possible water deficit in leaves. METHODS Four plant species with different FWU strategies were studied in a ferruginous rupestrian field with frequent fog. Gas exchange and water potential were measured before dawn and at midday during the dry and rainy seasons, separating foggy from non-foggy days during the dry season. RESULTS The FWU speed negatively influences CO2 assimilation in the dry season, possibly because of its negative relationship with stomatal conductance, since reduced stomatal aperture impairs carbon entrance. Fog presence increased leaf water potential both in early morning and midday during the dry season. However, during the rainy season, the values of leaf water potential were lower at midday, than during the dry season with fog at midday, which favors leaf gas exchanges. CONCLUSIONS FWU interferes negatively, but briefly with CO2 assimilation. Nevertheless, FWU prevents water loss through transpiration and increases the water status of plants in the dry season. That is, FWU results in a compensation between CO2 assimilation and foliar hydration, which, in fact, is beneficial to the plants of this ecosystem.
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Affiliation(s)
- Daniela Boanares
- Departamento de Botânica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Alessandra R Kozovits
- Departamento de Biodiversidade, Evolução e Meio Ambiente, Universidade Federal de Ouro Preto, MG, Brasil
| | - José P Lemos-Filho
- Departamento de Botânica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Rosy M S Isaias
- Departamento de Botânica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Ricardo R R Solar
- Departamento de Genética, Ecologia e Evolução, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Alexandre A Duarte
- Departamento de Botânica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Tiago Vilas-Boas
- Departamento de Botânica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Marcel G C França
- Departamento de Botânica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
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Gong XW, Lü GH, He XM, Sarkar B, Yang XD. High Air Humidity Causes Atmospheric Water Absorption via Assimilating Branches in the Deep-Rooted Tree Haloxylon ammodendron in an Arid Desert Region of Northwest China. FRONTIERS IN PLANT SCIENCE 2019; 10:573. [PMID: 31156661 PMCID: PMC6530360 DOI: 10.3389/fpls.2019.00573] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/16/2019] [Indexed: 05/30/2023]
Abstract
Atmospheric water is one of the main water resources for plants in arid ecosystems. However, whether deep-rooted, tomentum-less desert trees can absorb atmospheric water via aerial organs and transport the water into their bodies remains poorly understood. In the present study, a woody, deep-rooted, tomentum-less plant, Haloxylon ammodendron (C.A. Mey.) Bunge, was selected as the experimental object to investigate the preconditions for and consequences of foliar water uptake. Plant water status, gas exchange, and 18O isotopic signatures of the plant were investigated following a typical rainfall pulse and a high-humidity exposure experiment. The results showed that a high content of atmospheric water was the prerequisite for foliar water uptake by H. ammodendron in the arid desert region. After atmospheric water was absorbed via the assimilating branches, which perform the function of leaves due to leaf degeneration, the plant transported the water to the secondary branches and trunk stems, but not to the taproot xylem or the soil, based on the 18O isotopic signatures of the specimen. Foliar water uptake altered the plant water status and gas exchange-related traits, i.e., water potential, stomatal conductance, transpiration rate, and instantaneous water use efficiency. Our results suggest that atmospheric water might be a subsidiary water resource for sustaining the survival and growth of deep-rooted plants in arid desert regions. These findings contribute to the knowledge of plant water physiology and restoration of desert plants in the arid regions of the planet.
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Affiliation(s)
- Xue-Wei Gong
- Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi, China
- College of Resources and Environmental Sciences, Xinjiang University, Urumqi, China
| | - Guang-Hui Lü
- Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi, China
- College of Resources and Environmental Sciences, Xinjiang University, Urumqi, China
- Institute of Arid Ecology and Environment, Xinjiang University, Urumqi, China
| | - Xue-Min He
- Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi, China
- College of Resources and Environmental Sciences, Xinjiang University, Urumqi, China
- Institute of Arid Ecology and Environment, Xinjiang University, Urumqi, China
| | - Binoy Sarkar
- Department of Animal and Plant Sciences, The University of Sheffield, Sheffield, United Kingdom
- Future Industries Institute, University of South Australia, Mawson Lakes, SA, Australia
| | - Xiao-Dong Yang
- Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi, China
- College of Resources and Environmental Sciences, Xinjiang University, Urumqi, China
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23
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Berry ZC, Emery NC, Gotsch SG, Goldsmith GR. Foliar water uptake: Processes, pathways, and integration into plant water budgets. PLANT, CELL & ENVIRONMENT 2019; 42:410-423. [PMID: 30194766 DOI: 10.1111/pce.13439] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/27/2018] [Accepted: 08/28/2018] [Indexed: 05/04/2023]
Abstract
Nearly all plant families, represented across most major biomes, absorb water directly through their leaves. This phenomenon is commonly referred to as foliar water uptake. Recent studies have suggested that foliar water uptake provides a significant water subsidy that can influence both plant water and carbon balance across multiple spatial and temporal scales. Despite this, our mechanistic understanding of when, where, how, and to what end water is absorbed through leaf surfaces remains limited. We first review the evidence for the biophysical conditions necessary for foliar water uptake to occur, focusing on the plant and atmospheric water potentials necessary to create a gradient for water flow. We then consider the different pathways for uptake, as well as the potential fates of the water once inside the leaf. Given that one fate of water from foliar uptake is to increase leaf water potentials and contribute to the demands of transpiration, we also provide a quantitative synthesis of observed rates of change in leaf water potential and total fluxes of water into the leaf. Finally, we identify critical research themes that should be addressed to effectively incorporate foliar water uptake into traditional frameworks of plant water movement.
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Affiliation(s)
- Z Carter Berry
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Nathan C Emery
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Sybil G Gotsch
- Department of Biology, Franklin and Marshall College, Lancaster, Pennsylvania, USA
| | - Gregory R Goldsmith
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
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25
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Steppe K. The potential of the tree water potential. TREE PHYSIOLOGY 2018; 38:937-940. [PMID: 29897591 DOI: 10.1093/treephys/tpy064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 05/22/2018] [Indexed: 06/08/2023]
Abstract
Non-invasive quantification of tree water potential is one of the grand challenges for assessing the fate of trees and forests in the coming decades. Tree water potential is a robust and direct indicator of tree water status and is preferably used to track how trees, forests and vegetation in general respond to changes in climate and drought. In this issue of Tree Physiology, Dietrich et al. (2018) predict the daily canopy water potential of mature temperate trees from tree water deficit derived from stem diameter variation measurements.
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Affiliation(s)
- Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Belgium
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Steppe K, Vandegehuchte MW, Van de Wal BAE, Hoste P, Guyot A, Lovelock CE, Lockington DA. Direct uptake of canopy rainwater causes turgor-driven growth spurts in the mangrove Avicennia marina. TREE PHYSIOLOGY 2018; 38:979-991. [PMID: 29562244 DOI: 10.1093/treephys/tpy024] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 02/13/2018] [Indexed: 06/08/2023]
Abstract
Mangrove forests depend on a dense structure of sufficiently large trees to fulfil their essential functions as providers of food and wood for animals and people, CO2 sinks and protection from storms. Growth of these forests is known to be dependent on the salinity of soil water, but the influence of foliar uptake of rainwater as a freshwater source, additional to soil water, has hardly been investigated. Under field conditions in Australia, stem diameter variation, sap flow and stem water potential of the grey mangrove (Avicennia marina (Forssk.) Vierh.) were simultaneously measured during alternating dry and rainy periods. We found that sap flow in A. marina was reversed, from canopy to roots, during and shortly after rainfall events. Simultaneously, stem diameters rapidly increased with growth rates up to 70 μm h-1, which is about 25-75 times the normal growth rate reported in temperate trees. A mechanistic tree model was applied to provide evidence that A. marina trees take up water through their leaves, and that this water contributes to turgor-driven stem growth. Our results indicate that direct uptake of freshwater by the canopy during rainfall supports mangrove tree growth and serve as a call to consider this water uptake pathway if we aspire to correctly assess influences of changing rainfall patterns on mangrove tree growth.
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Affiliation(s)
- Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, Belgium
| | - Maurits W Vandegehuchte
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, Belgium
| | - Bart A E Van de Wal
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, Belgium
| | - Pieter Hoste
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, Belgium
| | - Adrien Guyot
- National Centre for Groundwater Research and Training, Flinders University, Adelaide, South Australia, Australia
- School of Civil Engineering, The University of Queensland, St. Lucia, Queensland, Australia
- Department of Civil Engineering, Monash University, Clayton, Victoria, Australia
| | - Catherine E Lovelock
- National Centre for Groundwater Research and Training, Flinders University, Adelaide, South Australia, Australia
- School of Biological Sciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - David A Lockington
- National Centre for Groundwater Research and Training, Flinders University, Adelaide, South Australia, Australia
- School of Civil Engineering, The University of Queensland, St. Lucia, Queensland, Australia
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27
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Barbeta A, Peñuelas J. Relative contribution of groundwater to plant transpiration estimated with stable isotopes. Sci Rep 2017; 7:10580. [PMID: 28874685 PMCID: PMC5585407 DOI: 10.1038/s41598-017-09643-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/27/2017] [Indexed: 11/16/2022] Open
Abstract
Water stored underground in the saturated and subsurface zones below the soil are important sources of water for plants in water-limited ecosystems. The presence of deep-rooted plants worldwide, however, suggests that the use of groundwater is not restricted to arid and seasonally dry ecosystems. We compiled the available data (71 species) on the relative contribution of groundwater to plant water estimated using stable isotopes and mixing models, which provided information about relative groundwater use, and analyzed their variation across different climates, seasons, plant types, edaphic conditions, and landscape positions. Plant use of groundwater was more likely at sites with a pronounced dry season, and represented on average 49 per cent of transpired water in dry seasons and 28 per cent in wet seasons. The relative contribution of groundwater to plant-water uptake was higher on rocky substrates (saprolite, fractured bedrock), which had reduced groundwater uptake when this source was deep belowground. In addition, we found that the connectivity between groundwater pools and plant water may be quantitatively larger and more widespread than reported by recent global estimations based on isotopic averaged values. Earth System Models should account for the feedbacks between transpiration and groundwater recharge.
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Affiliation(s)
- Adrià Barbeta
- ISPA, Bordeaux Science Agro, INRA, 33140, Villenave d'Ornon, France. .,CSIC, Global Ecology Unit CREAF-CSIC-UAB, E-08193, Bellaterra (Catalonia), Spain. .,CREAF, E-08193, Cerdanyola del Vallès (Catalonia), Spain.
| | - Josep Peñuelas
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, E-08193, Bellaterra (Catalonia), Spain.,CREAF, E-08193, Cerdanyola del Vallès (Catalonia), Spain
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28
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Nguyen HT, Meir P, Sack L, Evans JR, Oliveira RS, Ball MC. Leaf water storage increases with salinity and aridity in the mangrove Avicennia marina: integration of leaf structure, osmotic adjustment and access to multiple water sources. PLANT, CELL & ENVIRONMENT 2017; 40:1576-1591. [PMID: 28382635 DOI: 10.1111/pce.12962] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/17/2017] [Accepted: 03/28/2017] [Indexed: 05/20/2023]
Abstract
Leaf structure and water relations were studied in a temperate population of Avicennia marina subsp. australasica along a natural salinity gradient [28 to 49 parts per thousand (ppt)] and compared with two subspecies grown naturally in similar soil salinities to those of subsp. australasica but under different climates: subsp. eucalyptifolia (salinity 30 ppt, wet tropics) and subsp. marina (salinity 46 ppt, arid tropics). Leaf thickness, leaf dry mass per area and water content increased with salinity and aridity. Turgor loss point declined with increase in soil salinity, driven mainly by differences in osmotic potential at full turgor. Nevertheless, a high modulus of elasticity (ε) contributed to maintenance of high cell hydration at turgor loss point. Despite similarity among leaves in leaf water storage capacitance, total leaf water storage increased with increasing salinity and aridity. The time that stored water alone could sustain an evaporation rate of 1 mmol m-2 s-1 ranged from 77 to 126 min from subspecies eucalyptifolia to ssp. marina, respectively. Achieving full leaf hydration or turgor would require water from sources other than the roots, emphasizing the importance of multiple water sources to growth and survival of Avicennia marina across gradients in salinity and aridity.
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Affiliation(s)
- Hoa T Nguyen
- Plant Science Division, Research School of Biology, The Australian National University, Acton, Australian Capital Territory, 2601, Australia
- Department of Botany, Faculty of Agronomy, Vietnam National University of Agriculture, Trau Quy, Gia Lam, Hanoi, 131000, Vietnam
| | - Patrick Meir
- Plant Science Division, Research School of Biology, The Australian National University, Acton, Australian Capital Territory, 2601, Australia
- School of GeoSciences, University of Edinburgh, Crew Building, West Mains Road, Edinburgh, EH9 3JN, UK
| | - Lawren Sack
- Department of Ecology and Evolution, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - John R Evans
- Plant Science Division, Research School of Biology, The Australian National University, Acton, Australian Capital Territory, 2601, Australia
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, CP6109, Campinas, São Paulo, Brazil
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, The Australian National University, Acton, Australian Capital Territory, 2601, Australia
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29
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Inferring foliar water uptake using stable isotopes of water. Oecologia 2017; 184:763-766. [DOI: 10.1007/s00442-017-3917-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/11/2017] [Indexed: 12/13/2022]
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30
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Goldsmith GR, Bentley LP, Shenkin A, Salinas N, Blonder B, Martin RE, Castro‐Ccossco R, Chambi‐Porroa P, Diaz S, Enquist BJ, Asner GP, Malhi Y. Variation in leaf wettability traits along a tropical montane elevation gradient. THE NEW PHYTOLOGIST 2017; 214:989-1001. [PMID: 27463359 PMCID: PMC5412938 DOI: 10.1111/nph.14121] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/27/2016] [Indexed: 05/26/2023]
Abstract
Leaf wetting is often considered to have negative effects on plant function, such that wet environments may select for leaves with certain leaf surface, morphological, and architectural traits that reduce leaf wettability. However, there is growing recognition that leaf wetting can have positive effects. We measured variation in two traits, leaf drip tips and leaf water repellency, in a series of nine tropical forest communities occurring along a 3300-m elevation gradient in southern Peru. To extend this climatic gradient, we also assembled published leaf water repellency values from 17 additional sites. We then tested hypotheses for how these traits should vary as a function of climate. Contrary to expectations, we found that the proportion of species with drip tips did not increase with increasing precipitation. Instead, drip tips increased with increasing temperature. Moreover, leaf water repellency was very low in our sites and the global analysis indicated high repellency only in sites with low precipitation and temperatures. Our findings suggest that drip tips and repellency may not solely reflect the negative effects of wetting on plant function. Understanding the drivers of leaf wettability traits can provide insight into the effects of leaf wetting on plant, community, and ecosystem function.
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Affiliation(s)
- Gregory R. Goldsmith
- Environmental Change InstituteSchool of Geography and the EnvironmentUniversity of OxfordOxford, OX1 3QYUK
- Ecosystem Fluxes GroupLaboratory for Atmospheric ChemistryPaul Scherrer Institute5232 VilligenSwitzerland
| | - Lisa Patrick Bentley
- Environmental Change InstituteSchool of Geography and the EnvironmentUniversity of OxfordOxford, OX1 3QYUK
| | - Alexander Shenkin
- Environmental Change InstituteSchool of Geography and the EnvironmentUniversity of OxfordOxford, OX1 3QYUK
| | - Norma Salinas
- Environmental Change InstituteSchool of Geography and the EnvironmentUniversity of OxfordOxford, OX1 3QYUK
- Universidad Nacional San Antonio Abad del CuscoAvenida de la Cultura, Nro. 733CuscoPeru
| | - Benjamin Blonder
- Environmental Change InstituteSchool of Geography and the EnvironmentUniversity of OxfordOxford, OX1 3QYUK
| | - Roberta E. Martin
- Department of Global EcologyCarnegie Institution for Science260 Panama StreetStanfordCA 94305USA
| | - Rosa Castro‐Ccossco
- Universidad Nacional San Antonio Abad del CuscoAvenida de la Cultura, Nro. 733CuscoPeru
| | - Percy Chambi‐Porroa
- Universidad Nacional San Antonio Abad del CuscoAvenida de la Cultura, Nro. 733CuscoPeru
| | - Sandra Diaz
- Instituto Multidisciplinario de Biología Vegetal and FCEFyNUniversidad Nacional de Córdoba – CONICETC.C. 4955000 CórdobaArgentina
| | - Brian J. Enquist
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonAZ 85721USA
| | - Gregory P. Asner
- Department of Global EcologyCarnegie Institution for Science260 Panama StreetStanfordCA 94305USA
| | - Yadvinder Malhi
- Environmental Change InstituteSchool of Geography and the EnvironmentUniversity of OxfordOxford, OX1 3QYUK
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31
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Emery NC. Foliar uptake of fog in coastal California shrub species. Oecologia 2016; 182:731-42. [DOI: 10.1007/s00442-016-3712-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 08/18/2016] [Indexed: 10/21/2022]
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32
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Eller CB, Burgess SSO, Oliveira RS. Environmental controls in the water use patterns of a tropical cloud forest tree species, Drimys brasiliensis (Winteraceae). TREE PHYSIOLOGY 2015; 35:387-399. [PMID: 25716877 DOI: 10.1093/treephys/tpv001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 01/04/2015] [Indexed: 06/04/2023]
Abstract
Trees from tropical montane cloud forest (TMCF) display very dynamic patterns of water use. They are capable of downwards water transport towards the soil during leaf-wetting events, likely a consequence of foliar water uptake (FWU), as well as high rates of night-time transpiration (Enight) during drier nights. These two processes might represent important sources of water losses and gains to the plant, but little is known about the environmental factors controlling these water fluxes. We evaluated how contrasting atmospheric and soil water conditions control diurnal, nocturnal and seasonal dynamics of sap flow in Drimys brasiliensis (Miers), a common Neotropical cloud forest species. We monitored the seasonal variation of soil water content, micrometeorological conditions and sap flow of D. brasiliensis trees in the field during wet and dry seasons. We also conducted a greenhouse experiment exposing D. brasiliensis saplings under contrasting soil water conditions to deuterium-labelled fog water. We found that during the night D. brasiliensis possesses heightened stomatal sensitivity to soil drought and vapour pressure deficit, which reduces night-time water loss. Leaf-wetting events had a strong suppressive effect on tree transpiration (E). Foliar water uptake increased in magnitude with drier soil and during longer leaf-wetting events. The difference between diurnal and nocturnal stomatal behaviour in D. brasiliensis could be attributed to an optimization of carbon gain when leaves are dry, as well as minimization of nocturnal water loss. The leaf-wetting events on the other hand seem important to D. brasiliensis water balance, especially during soil droughts, both by suppressing tree transpiration (E) and as a small additional water supply through FWU. Our results suggest that decreases in leaf-wetting events in TMCF might increase D. brasiliensis water loss and decrease its water gains, which could compromise its ecophysiological performance and survival during dry periods.
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Affiliation(s)
- Cleiton B Eller
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, CP6109, Campinas, SP, Brazil
| | - Stephen S O Burgess
- School of Plant Biology, The University of Western Australia - UWA, Perth, WA 6009, Australia
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, CP6109, Campinas, SP, Brazil School of Plant Biology, The University of Western Australia - UWA, Perth, WA 6009, Australia
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33
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Steppe K, Vandegehuchte MW, Tognetti R, Mencuccini M. Sap flow as a key trait in the understanding of plant hydraulic functioning. TREE PHYSIOLOGY 2015; 35:341-5. [PMID: 25926534 DOI: 10.1093/treephys/tpv033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Affiliation(s)
- Kathy Steppe
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium;
| | - Maurits W Vandegehuchte
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
| | - Roberto Tognetti
- Dipartimento di Bioscienze e Territorio, Universita' degli Studi del Molise, 86090 Pesche, Italy
| | - Maurizio Mencuccini
- School of GeoSciences, University of Edinburgh, Crew Building, West Mains Road, Edinburgh EH9 3JN, UK; ICREA at CREAF, Universidad Autonoma de Barcelona, Cerdanyola del Valles, Barcelona, Spain
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Abstract
We investigated the possible use of dew as a water source for three desert plant species native to the Negev Desert: an annual Salsola inermis, and two perennials Artemisia sieberi and Haloxylon scoparium, with different rooting depths of 15, 30 and 90 cm, respectively. We quantified dew-water inputs and used stable isotope analyses to determine the proportion of dew as compared to the proportion of soil water each species utilized. Dew was isotopically enriched (δD values ranged from -25 to 5 ‰), relative to rainfall with δD values that ranged from -40 to -20 ‰ and relative to soil water with δD values that ranged from -65 to -35 ‰. Using a two-source isotope mixing model, we found that S. inermis, A. sieberi and H. scoparium used, on average, 56, 63 and 46 % of their water from dewfall, respectively. Our results suggest that dew-water utilization by Negev Desert plants is highly significant ecologically and thus may be more common than previously thought. In light of future predicted climate change, it may be increasingly important for plants of the Negev Desert to make use of dew as a water resource as it may play an important role in their ability to cope with the associated hydrological constraints predicted for the Negev region.
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Laur J, Hacke UG. Exploring Picea glauca aquaporins in the context of needle water uptake and xylem refilling. THE NEW PHYTOLOGIST 2014; 203:388-400. [PMID: 24702644 DOI: 10.1111/nph.12806] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 03/09/2014] [Indexed: 05/25/2023]
Abstract
Conifer needles have been reported to absorb water under certain conditions. Radial water movement across needle tissues is likely influenced by aquaporin (AQP) water channels. Foliar water uptake and AQP localization in Picea glauca needles were studied using physiological and microscopic methods. AQP expression was measured using quantitative real-time PCR. Members of the AQP gene family in spruce were identified using homology search tools. Needles of drought-stressed plants absorbed water when exposed to high relative humidity (RH). AQPs were present in the endodermis-like bundle sheath, in phloem cells and in the transfusion parenchyma of needles. Up-regulation of AQPs in high RH coincided with embolism repair in stem xylem. The present study also provides the most comprehensive functional and phylogenetic analysis of spruce AQPs to date. Thirty putative complete AQP sequences were found. Our findings are consistent with the hypothesis that AQPs facilitate radial water movement from the needle epidermis towards the vascular tissue. Foliar water uptake may occur in late winter when needles are covered by melting snow and may provide a water source for embolism repair before the beginning of the growing season.
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Affiliation(s)
- Joan Laur
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Uwe G Hacke
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
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