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Walthert L, Etzold S, Carminati A, Saurer M, Köchli R, Zweifel R. Coordination between degree of isohydricity and depth of root water uptake in temperate tree species. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174346. [PMID: 38944298 DOI: 10.1016/j.scitotenv.2024.174346] [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: 02/21/2024] [Revised: 06/26/2024] [Accepted: 06/26/2024] [Indexed: 07/01/2024]
Abstract
In an increasingly dry environment, it is crucial to understand how tree species use soil water and cope with drought. However, there is still a knowledge gap regarding the relationships between species-specific stomatal behaviour, spatial root distribution, and root water uptake (RWU) dynamics. Our study aimed to investigate above- and below-ground aspects of water use during soil drying periods in four temperate tree species that differ in stomatal behaviour: two isohydric tracheid-bearing conifers, Scots pine and Norway spruce, and two more anisohydric deciduous species, the diffuse-porous European beech, and the ring-porous Downy oak. From 2015 to 2020, soil-tree-atmosphere-continuum parameters were measured for each species in monospecific forests where trees had no access to groundwater. The hourly time series included data on air temperature, vapor pressure deficit, soil water potential, soil hydraulic conductivity, and RWU to a depth of 2 m. Analysis of drought responses included data on stem radius, leaf water potential, estimated osmotically active compounds, and drought damage. Our study reveals an inherent coordination between stomatal regulation, fine root distribution and water uptake. Compared to conifers, the more anisohydric water use of oak and beech was associated with less strict stomatal closure, greater investment in deep roots, four times higher maximum RWU, a shift of RWU to deeper soil layers as the topsoil dried, and a more pronounced soil drying below 1 m depth. Soil hydraulic conductivity started to limit RWU when values fell below 10-3 to 10-5 cm/d, depending on the soil. As drought progressed, oak and beech may also have benefited from their leaf osmoregulatory capacity, but at the cost of xylem embolism with around 50 % loss of hydraulic conductivity when soil water potential dropped below -1.25 MPa. Consideration of species-specific water use is crucial for forest management and vegetation modelling to improve forest resilience to drought.
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Affiliation(s)
- Lorenz Walthert
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland.
| | - Sophia Etzold
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zürich, Universitätsstrasse 16, 8092 Zürich, Switzerland
| | - Matthias Saurer
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Roger Köchli
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Roman Zweifel
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
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Manandhar A, Rimer IM, Soares Pereira T, Pichaco J, Rockwell FE, McAdam SAM. Dynamic soil hydraulic resistance regulates stomata. THE NEW PHYTOLOGIST 2024. [PMID: 39096020 DOI: 10.1111/nph.20020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Accepted: 07/05/2024] [Indexed: 08/04/2024]
Abstract
The onset of stomatal closure reduces transpiration during drought. In seed plants, drought causes declines in plant water status which increases leaf endogenous abscisic acid (ABA) levels required for stomatal closure. There are multiple possible points of increased belowground resistance in the soil-plant atmospheric continuum that could decrease leaf water potential enough to trigger ABA production and the subsequent decreases in transpiration. We investigate the dynamic patterns of leaf ABA levels, plant hydraulic conductance and the point of failure in the soil-plant conductance in the highly embolism-resistant species Callitris tuberculata using continuous dendrometer measurements of leaf water potential during drought. We show that decreases in transpiration and ABA biosynthesis begin before any permanent decreases in predawn water potential, collapse in soil-plant hydraulic pathway and xylem embolism spread. We find that a dynamic but recoverable increases in hydraulic resistance in the soil in close proximity to the roots is the most likely driver of declines in midday leaf water potential needed for ABA biosynthesis and the onset of decreases in transpiration.
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Affiliation(s)
- Anju Manandhar
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Ian M Rimer
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Talitha Soares Pereira
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Javier Pichaco
- Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Ave Reina Mercedes 10, 41012, Seville, Spain
| | - Fulton E Rockwell
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
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3
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Nadal-Sala D, Ruehr NK, Sabaté S. Overcoming drought: life traits driving tree strategies to confront drought stress. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3758-3761. [PMID: 38982745 DOI: 10.1093/jxb/erae219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
This insight article comments on: Ziegler C, Cochard, H, Stahl C, Bastien Gérard LF, Goret J, Heuret P, Levionnois S, Maillard P, Bonal D, Coste S. 2024. Residual water losses mediate the trade-off between growth and drought survival across saplings of 12 tropical rainforest tree species with contrasting hydraulic strategies. Journal of Experimental Botany 75, 4128-4147.
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Affiliation(s)
- Daniel Nadal-Sala
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF), Campus de Bellaterra (UAB) Edifici C, 08193, Cerdanyola del Vallès, Spain
- Universitat de Barcelona (UB), Ecology Section, Diagonal, 643, Barcelona, Spain
| | - Nadine K Ruehr
- Institute of Meteorology and Climate Research (IMK-IFU), KIT-Campus Alpin, Karlsruhe Institute of Technology (KIT), Kreuzeckbahnstr. 19, D-82467 Garmisch-Partenkirchen, Germany
| | - Santiago Sabaté
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF), Campus de Bellaterra (UAB) Edifici C, 08193, Cerdanyola del Vallès, Spain
- Universitat de Barcelona (UB), Ecology Section, Diagonal, 643, Barcelona, Spain
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4
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Berauer BJ, Steppuhn A, Schweiger AH. The multidimensionality of plant drought stress: The relative importance of edaphic and atmospheric drought. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38940730 DOI: 10.1111/pce.15012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 05/02/2024] [Accepted: 06/05/2024] [Indexed: 06/29/2024]
Abstract
Drought threatens plant growth and related ecosystem services. The emergence of plant drought stress under edaphic drought is well studied, whilst the importance of atmospheric drought only recently gained momentum. Yet, little is known about the interaction and relative contribution of edaphic and atmospheric drought on the emergence of plant drought stress. We conducted a gradient experiment, fully crossing gravimetric water content (GWC: maximum water holding capacity-permanent wilting point) and vapour pressure deficit (VPD: 1-2.25 kPa) using five wheat varieties from three species (Triticum monococcum, T. durum & T. aestivum). We quantified the occurrence of plant drought stress on molecular (abscisic acid), cellular (stomatal conductance), organ (leaf water potential) and stand level (evapotranspiration). Plant drought stress increased with decreasing GWC across all organizational levels. This effect was magnified nonlinearly by VPD after passing a critical threshold of soil water availability. At around 20%GWC (soil matric potential 0.012 MPa), plants lost their ability to regulate leaf water potential via stomata regulation, followed by the emergence of hydraulic dysfunction. The emergence of plant drought stress is characterized by changing relative contributions of soil versus atmosphere and their non-linear interaction. This highly non-linear response is likely to abruptly alter plant-related ecosystem services in a drying world.
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Affiliation(s)
- Bernd J Berauer
- Department of Plant Ecology, Institute of Landscape and Plant Ecology, University of Hohenheim, Stuttgart, Germany
| | - Anke Steppuhn
- Department of Molecular Botany, Institute of Biology, University of Hohenheim, Stuttgart, Germany
| | - Andreas H Schweiger
- Department of Plant Ecology, Institute of Landscape and Plant Ecology, University of Hohenheim, Stuttgart, Germany
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Paul M, Dalal A, Jääskeläinen M, Moshelion M, Schulman AH. Precision phenotyping of a barley diversity set reveals distinct drought response strategies. FRONTIERS IN PLANT SCIENCE 2024; 15:1393991. [PMID: 38984164 PMCID: PMC11231632 DOI: 10.3389/fpls.2024.1393991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 05/30/2024] [Indexed: 07/11/2024]
Abstract
Plants exhibit an array of drought responses and adaptations, where the trade-off between water loss and CO2 uptake for growth is mediated by regulation of stomatal aperture in response to soil water content (SWC), among other factors. For crop yield stability, the question is how drought timing and response patterns relate to post-drought growth resilience and vigor. We earlier identified, in a few reference varieties of barley that differed by the SWC at which transpiration was curtailed, two divergent water use strategies: water-saving ("isohydric") and water-spending ("anisohydric"). We proposed that an isohydric strategy may reduce risk from spring droughts in climates where the probability of precipitation increases during the growing season, whereas the anisohydric is consistent with environments having terminal droughts, or with those where dry periods are short and not seasonally progressive. Here, we have examined drought response physiology in an 81-line barley (Hordeum vulgare L.) diversity set that spans 20th century European breeding and identified several lines with a third, dynamic strategy. We found a strong positive correlation between vigor and transpiration, the dynamic group being highest for both. However, these lines curtailed daily transpiration at a higher SWC than the isohydric group. While the dynamic lines, particularly cv Hydrogen and Baronesse, were not the most resilient in terms of restoring initial growth rates, their strong initial vigor and high return to initial transpiration rates meant that their growth nevertheless surpassed more resilient lines during recovery from drought. The results will be of use for defining barley physiological ideotypes suited to future climate scenarios.
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Affiliation(s)
- Maitry Paul
- HiLIFE Institute of Biotechnology and Viikki Plant Science Centre (ViPS), University of Helsinki, Helsinki, Finland
| | - Ahan Dalal
- Faculty of Agriculture, Food and Environment, The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Marko Jääskeläinen
- HiLIFE Institute of Biotechnology and Viikki Plant Science Centre (ViPS), University of Helsinki, Helsinki, Finland
| | - Menachem Moshelion
- Faculty of Agriculture, Food and Environment, The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Alan H. Schulman
- HiLIFE Institute of Biotechnology and Viikki Plant Science Centre (ViPS), University of Helsinki, Helsinki, Finland
- Production Systems, Natural Resources Institute Finland (LUKE), Helsinki, Finland
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Nguyen TH, Lopez G, Seidel SJ, Lärm L, Bauer FM, Klotzsche A, Schnepf A, Gaiser T, Hüging H, Ewert F. Multi-year aboveground data of minirhizotron facilities in Selhausen. Sci Data 2024; 11:674. [PMID: 38909019 PMCID: PMC11193711 DOI: 10.1038/s41597-024-03535-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 06/17/2024] [Indexed: 06/24/2024] Open
Abstract
Improved understanding of crops' response to soil water stress is important to advance soil-plant system models and to support crop breeding, crop and varietal selection, and management decisions to minimize negative impacts. Studies on eco-physiological crop characteristics from leaf to canopy for different soil water conditions and crops are often carried out at controlled conditions. In-field measurements under realistic field conditions and data of plant water potential, its links with CO2 and H2O gas fluxes, and crop growth processes are rare. Here, we presented a comprehensive data set collected from leaf to canopy using sophisticated and comprehensive sensing techniques (leaf chlorophyll, stomatal conductance and photosynthesis, canopy CO2 exchange, sap flow, and canopy temperature) including detailed crop growth characteristics based on destructive methods (crop height, leaf area index, aboveground biomass, and yield). Data were acquired under field conditions with contrasting soil types, water treatments, and different cultivars of wheat and maize. The data from 2016 up to now will be made available for studying soil/water-plant relations and improving soil-plant-atmospheric continuum models.
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Affiliation(s)
- Thuy Huu Nguyen
- University of Bonn, Institute of Crop Science and Resource Conservation (INRES), Katzenburgweg 5, 53115, Bonn, Germany.
| | - Gina Lopez
- University of Bonn, Institute of Crop Science and Resource Conservation (INRES), Katzenburgweg 5, 53115, Bonn, Germany
| | - Sabine J Seidel
- University of Bonn, Institute of Crop Science and Resource Conservation (INRES), Katzenburgweg 5, 53115, Bonn, Germany
| | - Lena Lärm
- Agrosphere (IBG-3), Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Felix Maximilian Bauer
- Agrosphere (IBG-3), Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Anja Klotzsche
- Agrosphere (IBG-3), Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Andrea Schnepf
- Agrosphere (IBG-3), Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Thomas Gaiser
- University of Bonn, Institute of Crop Science and Resource Conservation (INRES), Katzenburgweg 5, 53115, Bonn, Germany
| | - Hubert Hüging
- University of Bonn, Institute of Crop Science and Resource Conservation (INRES), Katzenburgweg 5, 53115, Bonn, Germany
| | - Frank Ewert
- University of Bonn, Institute of Crop Science and Resource Conservation (INRES), Katzenburgweg 5, 53115, Bonn, Germany
- Leibniz Centre for Agricultural Landscape Research (ZALF), Institute of Landscape Systems Analysis, Eberswalder Strasse 84, 15374, Muencheberg, Germany
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7
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Zarebanadkouki M, Al Hamwi W, Abdalla M, Rahnemaie R, Schaller J. The effect of amorphous silica on soil-plant-water relations in soils with contrasting textures. Sci Rep 2024; 14:10277. [PMID: 38704511 PMCID: PMC11069543 DOI: 10.1038/s41598-024-60947-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 04/29/2024] [Indexed: 05/06/2024] Open
Abstract
This study investigates how amorphous silica (ASi) influences soil-plant-water interactions in distinct soil textures. A sandy loam and silty clay soil were mixed with 0 and 2% ASi, and their impact on soil retention and soil hydraulic conductivity curves were determined. In parallel, tomato plants (Solanum lycopersicum L.) were grown in experimental pots under controlled conditions. When plants were established, the soil was saturated, and a controlled drying cycle ensued until plants reached their wilting points. Soil water content, soil water potential, plant transpiration rate, and leaf water potential were monitored during this process. Results indicate a positive impact of ASi on the sandy loam soil, enhancing soil water content at field capacity (FC, factor of 1.3 times) and at permanent wilting point (PWP, a factor of 3.5 times), while its effect in silty clay loam was negligible (< 1.05 times). In addition, the presence of ASi prevented a significant drop in soil hydraulic conductivity ( K h ) at dry conditions. The K h of ASi-treated sandy loam and silty clay at PWP were 4.3 times higher than their respective control. Transpiration rates in plants grown in ASi-treated sandy loam soil under soil drying conditions were higher than in the control, attributed to improved soil hydraulic conductivity. At the same time, no significant difference was observed in the transpiration of plants treated with ASi in silty clay soil. This suggests ASi boosts soil-plant-water relationships in coarse-textured soils by maintaining heightened hydraulic conductivity, with no significant effect on fine-textured soils.
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Affiliation(s)
- Mohsen Zarebanadkouki
- Professorship for Soil Biophysics and Environmental Systems, Technical University of Munich, Munich, Germany.
| | - Wael Al Hamwi
- Leibniz Center for Agricultural Landscape Research (ZALF), Müncheberg, Germany
| | - Mohanned Abdalla
- Chair of Root-Soil Interaction, School of Life Sciences, Technical University of Munich, Munich, Germany
| | - Rasoul Rahnemaie
- Department of Soil Science, Tarbiat Modares University, Tehran, Iran
| | - Jörg Schaller
- Leibniz Center for Agricultural Landscape Research (ZALF), Müncheberg, Germany
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8
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Rüther E, Hertel D, Leuschner C. Intraspecific variation in fine root morphology of European beech: a root order-based analysis of phenotypic root morphospace. Oecologia 2024; 205:121-133. [PMID: 38698245 PMCID: PMC11144161 DOI: 10.1007/s00442-024-05558-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 04/17/2024] [Indexed: 05/05/2024]
Abstract
Fine roots are multifunctional organs that may change function with ageing or root branching events from primarily absorptive to resource transport and storage functions. It is not well understood, how fine root branching patterns and related root functional differentiation along the longitudinal root axis change with soil chemical and physical conditions. We examined the variation in fine root branching patterns (the relative frequency of 1st to 4th root orders) and root morphological and chemical traits of European beech trees with soil depth (topsoil vs. subsoil) and soil chemistry (five sites with acid to neutral/alkaline bedrock). Bedrock type and related soil chemistry had an only minor influence on branching patterns: base-poor, infertile sites showed no higher fine root branching than base-rich sites. The contribution of 1st-order root segments to total fine root length decreased at all sites from about 60% in the topsoil (including organic layer) to 45% in the lower subsoil. This change was associated with a decrease in specific root area and root N content and an increase in mean root diameter with soil depth, while root tissue density did not change consistently. We conclude that soil depth (which acts through soil physical and chemical drivers) influences the fine root branching patterns of beech much more than soil chemical variation across soil types. To examine whether changes in root function are indeed triggered by branching events or result from root ageing and diameter growth, spatially explicit root physiological and anatomical studies across root orders are needed.
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Affiliation(s)
- Eva Rüther
- Plant Ecology, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany
| | - Dietrich Hertel
- Plant Ecology, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany
| | - Christoph Leuschner
- Plant Ecology, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany.
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9
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Tang W, Liu X, Liang X, Liu H, Yu K, He P, McAdam S, Zhao H, Ye Q. Hydraulic vulnerability difference between branches and roots increases with environmental aridity. Oecologia 2024; 205:177-190. [PMID: 38772916 DOI: 10.1007/s00442-024-05562-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 05/01/2024] [Indexed: 05/23/2024]
Abstract
The vulnerability of plant xylem to embolism can be described as the water potential at which xylem conductivity is lost by 50% (P50). According to the traditional hypothesis of hydraulic vulnerability segmentation, the difference in vulnerability to embolism between branches and roots is positive (P50 root-branch > 0). It is not clear whether this occurs broadly across species or how segmentation might vary across aridity gradients. We compiled hydraulic and anatomical datasets from branches and roots across 104 woody species (including new measurements from 10 species) in four biomes to investigate the relationships between P50 root-branch and environmental factors associated with aridity. We found a positive P50 root-branch relationship across species, and evidence that P50 root-branch increases with aridity. Branch xylem hydraulic conductivity transitioned from more efficient (e.g., wider conduit, higher hydraulic conductivity) to safer (e.g., narrower conduit, more negative P50) in response to the increase of aridity, while root xylem hydraulic conductivity remained unchanged across aridity gradients. Our results demonstrate that the hydraulic vulnerability difference between branches and roots is more positive in species from arid regions, largely driven by modifications to branch traits.
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Affiliation(s)
- Weize Tang
- Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, No. 723, Xingke Road, Tianhe District, Guangzhou, 510650, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaorong Liu
- Sichuan University of Arts and Science, Tashi Road 519, Dazhou, 635000, China
| | - Xingyun Liang
- Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, No. 723, Xingke Road, Tianhe District, Guangzhou, 510650, China
| | - Hui Liu
- Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, No. 723, Xingke Road, Tianhe District, Guangzhou, 510650, China
| | - Kailiang Yu
- High Meadows Environmental Institute, Princeton University, Princeton, NJ, USA
| | - Pengcheng He
- Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, No. 723, Xingke Road, Tianhe District, Guangzhou, 510650, China
| | - Scott McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
| | - Han Zhao
- Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, No. 723, Xingke Road, Tianhe District, Guangzhou, 510650, China
| | - Qing Ye
- Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, No. 723, Xingke Road, Tianhe District, Guangzhou, 510650, China.
- College of Life Sciences, Gannan Normal University, Ganzhou, 341000, China.
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10
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Depardieu C, Lenz P, Marion J, Nadeau S, Girardin MP, Marchand W, Bégin C, Treydte K, Gessler A, Bousquet J, Savard MM, Isabel N. Contrasting physiological strategies explain heterogeneous responses to severe drought conditions within local populations of a widespread conifer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171174. [PMID: 38402972 DOI: 10.1016/j.scitotenv.2024.171174] [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: 10/23/2023] [Revised: 01/12/2024] [Accepted: 02/20/2024] [Indexed: 02/27/2024]
Abstract
Understanding how trees prioritize carbon gain at the cost of drought vulnerability under severe drought conditions is crucial for predicting which genetic groups and individuals will be resilient to future climate conditions. In this study, we investigated variations in growth, tree-ring anatomy as well as carbon and oxygen isotope ratios to assess the sensitivity and the xylem formation process in response to an episode of severe drought in 29 mature white spruce (Picea glauca [Moench] Voss) families grown in a common garden trial. During the drought episode, the majority of families displayed decreased growth and exhibited either sustained or increased intrinsic water-use efficiency (iWUE), which was largely influenced by reduced stomatal conductance as revealed by the dual carbon‑oxygen isotope approach. Different water-use strategies were detected within white spruce populations in response to drought conditions. Our results revealed intraspecific variation in the prevailing physiological mechanisms underlying drought response within and among populations of Picea glauca. The presence of different genetic groups reflecting diverse water-use strategies within this largely-distributed conifer is likely to lessen the negative effects of drought and decrease the overall forest ecosystems' sensitivity to it.
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Affiliation(s)
- Claire Depardieu
- Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Forest Research Centre, Département des sciences du bois et de la forêt, Université Laval, Québec, QC G1V 0A6, Canada; Natural Ressources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada.
| | - Patrick Lenz
- Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Natural Resources Canada, Canadian Forest Service, Canadian Wood Fibre Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada
| | - Joelle Marion
- Geological Survey of Canada, Natural Resources Canada, 490 rue de la Couronne, Québec, QC G1K 9A9, Canada
| | - Simon Nadeau
- Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Natural Resources Canada, Canadian Forest Service, Canadian Wood Fibre Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada
| | - Martin P Girardin
- Natural Ressources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada; Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Succ. Centre-ville, Montréal, QC H3C 3P8, Canada; Forest Research Institute, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l'Université, Rouyn-Noranda, QC J9X 5E4, Canada
| | - William Marchand
- Natural Ressources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada; Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Succ. Centre-ville, Montréal, QC H3C 3P8, Canada; Forest Research Institute, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l'Université, Rouyn-Noranda, QC J9X 5E4, Canada
| | - Christian Bégin
- Geological Survey of Canada, Natural Resources Canada, 490 rue de la Couronne, Québec, QC G1K 9A9, Canada
| | - Kerstin Treydte
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland; Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, Switzerland
| | - Jean Bousquet
- Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Forest Research Centre, Département des sciences du bois et de la forêt, Université Laval, Québec, QC G1V 0A6, Canada
| | - Martine M Savard
- Geological Survey of Canada, Natural Resources Canada, 490 rue de la Couronne, Québec, QC G1K 9A9, Canada
| | - Nathalie Isabel
- Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Natural Ressources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada
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11
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Bachofen C, Tumber-Dávila SJ, Mackay DS, McDowell NG, Carminati A, Klein T, Stocker BD, Mencuccini M, Grossiord C. Tree water uptake patterns across the globe. THE NEW PHYTOLOGIST 2024. [PMID: 38649790 DOI: 10.1111/nph.19762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 03/13/2024] [Indexed: 04/25/2024]
Abstract
Plant water uptake from the soil is a crucial element of the global hydrological cycle and essential for vegetation drought resilience. Yet, knowledge of how the distribution of water uptake depth (WUD) varies across species, climates, and seasons is scarce relative to our knowledge of aboveground plant functions. With a global literature review, we found that average WUD varied more among biomes than plant functional types (i.e. deciduous/evergreen broadleaves and conifers), illustrating the importance of the hydroclimate, especially precipitation seasonality, on WUD. By combining records of rooting depth with WUD, we observed a consistently deeper maximum rooting depth than WUD with the largest differences in arid regions - indicating that deep taproots act as lifelines while not contributing to the majority of water uptake. The most ubiquitous observation across the literature was that woody plants switch water sources to soil layers with the highest water availability within short timescales. Hence, seasonal shifts to deep soil layers occur across the globe when shallow soils are drying out, allowing continued transpiration and hydraulic safety. While there are still significant gaps in our understanding of WUD, the consistency across global ecosystems allows integration of existing knowledge into the next generation of vegetation process models.
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Affiliation(s)
- Christoph Bachofen
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, 1015, Lausanne, Switzerland
- Functional Plant Ecology, Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape WSL, 1015, Lausanne, Switzerland
| | - Shersingh Joseph Tumber-Dávila
- Department of Environmental Studies, Dartmouth College, Hanover, NH, 03755, USA
- Harvard Forest, Harvard University, Petersham, MA, 01316, USA
| | - D Scott Mackay
- Department of Geography, University at Buffalo, Buffalo, NY, 14261, USA
| | - Nate G McDowell
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
- School of Biological Sciences, Washington State University, Pullman, WA, 99163, USA
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zürich, 8092, Zürich, Switzerland
| | - Tamir Klein
- Plant & Environmental Sciences Department, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Benjamin D Stocker
- Institute of Geography, University of Bern, Bern, 3013, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, 3013, Bern, Switzerland
| | - Maurizio Mencuccini
- CREAF, Cerdanyola del Vallès, Barcelona, 08193, Spain
- ICREA at CREAF, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Charlotte Grossiord
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, 1015, Lausanne, Switzerland
- Functional Plant Ecology, Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape WSL, 1015, Lausanne, Switzerland
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12
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Andriantelomanana T, Améglio T, Delzon S, Cochard H, Herbette S. Unpacking the point of no return under drought in poplar: insight from stem diameter variation. THE NEW PHYTOLOGIST 2024; 242:466-478. [PMID: 38406847 DOI: 10.1111/nph.19615] [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: 11/15/2023] [Accepted: 02/02/2024] [Indexed: 02/27/2024]
Abstract
A specific, robust threshold for drought-induced tree mortality is needed to improve the prediction of forest dieback. Here, we tested the relevance of continuous measurements of stem diameter variations for identifying such a threshold, their relationship with hydraulic and cellular damage mechanisms, and the influence of growth conditions on these relationships. Poplar saplings were grown under well-watered, water-limited, or light-limited conditions and then submitted to a drought followed by rewatering. Stem diameter was continuously measured to investigate two parameters: the percentage loss of diameter (PLD) and the percentage of diameter recovery (DR) following rewatering. Water potentials, stomatal conductance, embolism, and electrolyte leakage were also measured, and light microscopy allowed investigating cell collapse induced by drought. The water release observed through loss of diameter occurred throughout the drought, regardless of growth conditions. Poplars did not recover from drought when PLD reached a threshold and this differed according to growth conditions but remained linked to cell resistance to damage and collapse. Our findings shed new light on the mechanisms of drought-induced tree mortality and indicate that PLD could be a relevant indicator of drought-induced tree mortality, regardless of the growth conditions.
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Affiliation(s)
| | - Thierry Améglio
- Université Clermont Auvergne, INRAE, PIAF, Clermont-Ferrand, 63000, France
| | - Sylvain Delzon
- Université Bordeaux, INRAE, BIOGECO, Pessac, 33615, France
| | - Hervé Cochard
- Université Clermont Auvergne, INRAE, PIAF, Clermont-Ferrand, 63000, France
| | - Stephane Herbette
- Université Clermont Auvergne, INRAE, PIAF, Clermont-Ferrand, 63000, France
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13
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Bourbia I, Brodribb TJ. Stomatal response to VPD is not triggered by changes in soil-leaf hydraulic conductance in Arabidopsis or Callitris. THE NEW PHYTOLOGIST 2024; 242:444-452. [PMID: 38396304 DOI: 10.1111/nph.19607] [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: 01/09/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024]
Abstract
Stomatal closure under high VPDL (leaf to air vapour pressure deficit) is a primary means by which plants prevent large excursions in transpiration rate and leaf water potential (Ψleaf) that could lead to tissue damage. Yet, the drivers of this response remain controversial. Changes in Ψleaf appear to drive stomatal VPDL response, but many argue that dynamic changes in soil-to-leaf hydraulic conductance (Ks-l) make an important contribution to this response pathway, even in well-hydrated soils. Here, we examined whether the regulation of whole plant stomatal conductance (gc) in response to typical changes in daytime VPDL is influenced by dynamic changes in Ks-l. We use well-watered plants of two species with contrasting ecological and physiological features: the herbaceous Arabidopsis thaliana (ecotype Columbia-0) and the dry forest conifer Callitris rhomboidea. The dynamics of Ks-l and gc were continuously monitored by combining concurrent in situ measurements of Ψleaf using an open optical dendrometer and whole plant transpiration using a balance. Large changes in VPDL were imposed to induce stomatal closure and observe the impact on Ks-l. In both species, gc was observed to decline substantially as VPDL increased, while Ks-l remained stable. Our finding suggests that stomatal regulation of transpiration is not contingent on a decrease in Ks-l. Static Ks-l provides a much simpler explanation for transpiration control in hydrated plants and enables simplified modelling and new methods for monitoring plant water use in the field.
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Affiliation(s)
- Ibrahim Bourbia
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, Tas., 7001, Australia
| | - Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, Tas., 7001, Australia
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14
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Xiao T, Li P, Fei W, Wang J. Effects of vegetation roots on the structure and hydraulic properties of soils: A perspective review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167524. [PMID: 37793452 DOI: 10.1016/j.scitotenv.2023.167524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 09/22/2023] [Accepted: 09/29/2023] [Indexed: 10/06/2023]
Abstract
This paper aims to provide a state-of-the-art review on the effects of vegetation roots on the soil structure and soil hydraulic properties. After a thorough review of current studies, the effects of vegetation roots are summarized into four: root exudation, root penetration, root water uptake and root decay. Root exudates alter the size and stability of aggregates, the contact angle of soil, and the viscosity and surface tension of pore fluid; root exudates of crops always increase the soil water retention capacity and decrease the soil saturated hydraulic conductivity. Root penetration creates new pores or clogs existing pores during root growth, and root parameters (e.g., root biomass density, root diameter and root length density) are well correlated to soil hydraulic properties. Root water uptake can apparently increase the soil water retention capacity by providing an additional negative pressure and induce micro-fissures and macropores in the rhizosphere soil. Root decay modifies the pore structure and water repellency of soil, resulting in the increase of soil macro-porosity, soil water retention, and the saturated hydraulic conductivity or steady infiltration rate. Some of the above four effects may be difficult to be distinguished, and most importantly each is highly time-dependent and influenced by a multitude of plant-related and soil-related factors. Therefore, it remains a significant challenge to comprehend and quantify the effects of vegetation roots on the soil structure and soil hydraulic properties. Unsolved questions and disputes that require further investigations in the future are summarized in this review.
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Affiliation(s)
- Tao Xiao
- State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, China.
| | - Ping Li
- State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, China; Water Cycle and Geological Environment Observation and Research Station for the Chinese Loess Plateau, Ministry of Education, Zhengning 745339, China.
| | - Wenbin Fei
- Department of Infrastructure Engineering, The University of Melbourne, Parkville, Australia.
| | - Jiading Wang
- State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, China.
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15
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Yang Y, Ma X, Yan L, Li Y, Wei S, Teng Z, Zhang H, Tang W, Peng S, Li Y. Soil-root interface hydraulic conductance determines responses of photosynthesis to drought in rice and wheat. PLANT PHYSIOLOGY 2023; 194:376-390. [PMID: 37706538 DOI: 10.1093/plphys/kiad498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/28/2023] [Accepted: 08/22/2023] [Indexed: 09/15/2023]
Abstract
Rice (Oryza sativa) production consumes a huge amount of fresh water, and improvement of drought tolerance in rice is important to conserve water resources and minimize yield loss under drought. However, processes to improve drought tolerance in rice have not been fully explored, and a comparative study between rice and wheat (Triticum aestivum) is an effective method to understand the mechanisms determining drought tolerance capacity. In the present study, we applied short-term drought stress to Shanyou 63 rice and Yannong 19 wheat to create a range of water potentials and investigated the responses of gas exchange, plant hydraulic conductance, and root morphological and anatomical traits to soil drought. We found that photosynthesis in rice was more sensitive to drought stress than that in wheat, which was related to differences in the decline of stomatal conductance and plant hydraulic conductance (Kplant). The decline of Kplant under drought was mainly driven by the decrease of soil-root interface hydraulic conductance (Ki) because Ki was more sensitive to drought than root and shoot hydraulic conductance and the soil-root interface contributed to >40% of whole-plant hydraulic resistance in both crops. Root shrinkage in response to drought was more severe in rice than that in wheat, which explains the larger depression of Ki and Kplant under drought stress in rice. We concluded that the decline of Ki drives the depression of Kplant and photosynthesis in both crops, and the plasticity of root morphology and anatomy is important in determining drought tolerance capacity.
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Affiliation(s)
- Yuhan Yang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xiaolin Ma
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Lu Yan
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yingchao Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Suhan Wei
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Zhipeng Teng
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Hong Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Wei Tang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Shaobing Peng
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yong Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
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16
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Gal A, Dalal A, Anfang M, Sharma D, Binenbaum J, Muchaki P, Kumar R, Egbaria A, Duarte KE, Kelly G, de Souza WR, Sade N. Plasma membrane aquaporins regulate root hydraulic conductivity in the model plant Setaria viridis. PLANT PHYSIOLOGY 2023; 193:2640-2660. [PMID: 37607257 DOI: 10.1093/plphys/kiad469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/26/2023] [Accepted: 08/02/2023] [Indexed: 08/24/2023]
Abstract
The high rate of productivity observed in panicoid crops is in part due to their extensive root system. Recently, green foxtail (Setaria viridis) has emerged as a genetic model system for panicoid grasses. Natural accessions of S. viridis originating from different parts of the world, with differential leaf physiological behavior, have been identified. This work focused on understanding the physiological and molecular mechanisms controlling root hydraulic conductivity and root-to-shoot gas exchange signaling in S. viridis. We identified 2 accessions, SHA and ZHA, with contrasting behavior at the leaf, root, and whole-plant levels. Our results indicated a role for root aquaporin (AQP) plasma membrane (PM) intrinsic proteins in the differential behavior of SHA and ZHA. Moreover, a different root hydraulic response to low levels of abscisic acid between SHA and ZHA was observed, which was associated with root AQPs. Using cell imaging, biochemical, and reverse genetic approaches, we identified PM intrinsic protein 1;6 (PIP1;6) as a possible PIP1 candidate that regulates radial root hydraulics and root-to-shoot signaling of gas exchange in S. viridis. In heterologous systems, PIP1;6 localized in the endoplasmic reticulum, and upon interaction with PIP2s, relocalization to the PM was observed. PIP1;6 was predominantly expressed at the root endodermis. Generation of knockout PIP1;6 plants (KO-PIP1;6) in S. viridis showed altered root hydraulic conductivity, altered gas exchange, and alteration of root transcriptional patterns. Our results indicate that PIPs are essential in regulating whole-plant water homeostasis in S. viridis. We conclude that root hydraulic conductivity and gas exchange are positively associated and are regulated by AQPs.
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Affiliation(s)
- Atara Gal
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ahan Dalal
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 69978, Israel
| | - Moran Anfang
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 69978, Israel
| | - Davinder Sharma
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 69978, Israel
| | - Jenia Binenbaum
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 69978, Israel
| | - Purity Muchaki
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 69978, Israel
| | - Rakesh Kumar
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 69978, Israel
| | - Aiman Egbaria
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 69978, Israel
| | - Karoline Estefani Duarte
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC (UFABC), Santo André 09210170, Brazil
| | - Gilor Kelly
- The Volcani Center, Institute of Plant Sciences, Agricultural Research Organization, Rishon Le-Zion 7505101, Israel
| | - Wagner Rodrigo de Souza
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC (UFABC), Santo André 09210170, Brazil
| | - Nir Sade
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 69978, Israel
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17
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Hameed S, Atif M, Perveen S. Role of gibberellins, neem leaf extract, and serine in improving wheat growth and grain yield under drought-triggered oxidative stress. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2023; 29:1675-1691. [PMID: 38162918 PMCID: PMC10754809 DOI: 10.1007/s12298-023-01402-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 11/27/2023] [Accepted: 12/06/2023] [Indexed: 01/03/2024]
Abstract
The foliar application of gibberellins (GA3), neem leaf extract (NLE) and serine can be proven as effective growth regulating agents to counter drought stress-related deleterious effects. The literature about the collaborative role of these substances in foliar spray application under drought stress is not available to this date. No single report is available in literature on combine foliar application of GA3, NLE, and serine in improving wheat growth and yield under drought-triggered oxidative stress. The objective of this study was to induct tolerance against drought stress in order to sustain maximum growth and yield of wheat varieties (Anaj-2017 and Galaxy-2013) with foliar applications of GA3, NLE, and serine. The current field trial was designed to disclose the protective role of these substances in wheat varieties (Anaj-2017 and Galaxy-2013) under water-deficit stress. Two irrigation levels, i.e., control (normal irrigation) and water stress (water deficit irrigation), and 5 levels of GA3, NLE and serine i.e., control (water spray), GA3 (10.0 ppm), NLE (10.0%), serine (9.5 mM), and mixture (GA3 + NLE + serine) in a 1:1:1 ratio was applied. Application of these substances improved the pigments (Chlorophyll a, b), carotenoids, growth, biomass, and grain yield traits of both wheat varieties under water-deficit stress. Activities of antioxidant enzymes (POD, CAT and SOD), and non-enzymatic antioxidants (proline, total phenolic contents, anthocyanin and free amino acids) were up-regulated under drought stress and with foliar spray treatments. The foliar applications of these substances reduced the drought triggered overproduction of lipid peroxidation (MDA) and H2O2. The study found that Galaxy-2013 variety is more tolerant to drought stress than Anaj-2017, while co-applied treatments (GA3 + NLE + serine) were shown to be the most effective among all applications. Supplementary Information The online version contains supplementary material available at 10.1007/s12298-023-01402-9.
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Affiliation(s)
- Sidra Hameed
- Department of Botany, Government College University, Faisalabad, 38000 Pakistan
| | - Muhammad Atif
- Department of Botany, Government College University, Faisalabad, 38000 Pakistan
| | - Shagufta Perveen
- Department of Botany, Government College University, Faisalabad, 38000 Pakistan
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18
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Yang Z, Gong J, Wang S, Jin T, Wang Y. Shifts bidirectional dependency between vegetation greening and soil moisture over the past four decades in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 897:166388. [PMID: 37597546 DOI: 10.1016/j.scitotenv.2023.166388] [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: 04/25/2023] [Revised: 07/19/2023] [Accepted: 08/16/2023] [Indexed: 08/21/2023]
Abstract
Soil moisture (SM) has changed significantly over the past 40 years in China, while NDVI has varied dramatically, leading to increasing regional conflict between vegetation growth and water resource use. Quantifying the bidirectional dependency between SM and NDVI is essential for understanding the balance between land vegetation and water resources. However, few studies have reported their mutual feedback and spatiotemporal bidirectional dependency. This paper aims to reveal the bidirectional dependency between SM and NDVI using Granger causality test to show spatiotemporal tendency coupling patterns through trend coupling analysis, wavelet transform, and lag correlation. The Results indicated that a coupling relationship existed between SM and NDVI over most of China. The unidirectional Granger effect between SM on NDVI was 58 %, the unidirectional Granger effect of NDVI on SM was 26 %, and the bidirectional Granger relationship between SM and NDVI was 16 %. The Granger relationship is different for different soil layers or land cover types. SM and NDVI increased together in 36 % of the land cover areas, but SM increased and NDVI decreased in 12 %, and the SM decreased and NDVI increased in 27 %. The trend coupling between SM and NDVI has spatial heterogeneity. There is no change rule of coupling relationship with drought variation, but SM and NDVI increased together with more overlapping ecological restoration projects. SM decreased with the increase of NDVI from 1982 to 2010 but has reversed since 2011. NDVI and SM co-increased significantly with the implementation of ecological restoration projects during 2011-2022. The coupling relationship has a time lag effect of 1-3 months, and the time lag of NDVI to SM of deep soil layers mainly occurred in Southern China. This study illustrated the coupling framework and feedback analysis between SM and vegetation greening, which is helpful for the scientific implementing ecological restoration projects and the management of ecosystem carbon and water cycles.
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Affiliation(s)
- Zhihui Yang
- Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jie Gong
- Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
| | - Shimei Wang
- Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Tiantian Jin
- Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yixu Wang
- Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
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19
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Cai G, Carminati A, Gleason SM, Javaux M, Ahmed MA. Soil-plant hydraulics explain stomatal efficiency-safety tradeoff. PLANT, CELL & ENVIRONMENT 2023; 46:3120-3127. [PMID: 36609853 DOI: 10.1111/pce.14536] [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: 07/24/2022] [Revised: 12/10/2022] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
The efficiency-safety tradeoff has been thoroughly investigated in plants, especially concerning their capacity to transport water and avoid embolism. Stomatal regulation is a vital plant behaviour to respond to soil and atmospheric water limitation. Recently, a stomatal efficiency-safety tradeoff was reported where plants with higher maximum stomatal conductance (gmax ) exhibited greater sensitivity to stomatal closure during soil drying, that is, less negative leaf water potential at 50% gmax (ψgs50 ). However, the underlying mechanism of this gmax -ψgs50 tradeoff remains unknown. Here, we utilized a soil-plant hydraulic model, in which stomatal closure is triggered by nonlinearity in soil-plant hydraulics, to investigate such tradeoff. Our simulations show that increasing gmax is aligned with less negative ψgs50 . Plants with higher gmax (also higher transpiration) require larger quantities of water to be moved across the rhizosphere, which results in a precipitous decrease in water potential at the soil-root interface, and therefore in the leaves. We demonstrated that the gmax -ψgs50 tradeoff can be predicted based on soil-plant hydraulics, and is impacted by plant hydraulic properties, such as plant hydraulic conductance, active root length and embolism resistance. We conclude that plants may therefore adjust their growth and/or their hydraulic properties to adapt to contrasting habitats and climate conditions.
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Affiliation(s)
- Gaochao Cai
- School of Agriculture, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Institute of Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zürich, Zurich, Switzerland
| | - Sean M Gleason
- United States Department of Agriculture, Water Management and Systems Research Unit, Agricultural Research Service, Fort Collins, Colorado, USA
| | - Mathieu Javaux
- Earth and Life Institute-Environmental Science, Universite catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Mutez Ali Ahmed
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Department of Land, Air and Water Resources, College of Agricultural and Environmental Sciences, University of California Davis, Davis, California, USA
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20
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Sevanto S, Gehring CA, Ryan MG, Patterson A, Losko AS, Vogel SC, Carter KR, Dickman LT, Espy MA, Kuske CR. Benefits of symbiotic ectomycorrhizal fungi to plant water relations depend on plant genotype in pinyon pine. Sci Rep 2023; 13:14424. [PMID: 37660169 PMCID: PMC10475095 DOI: 10.1038/s41598-023-41191-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 08/23/2023] [Indexed: 09/04/2023] Open
Abstract
Rhizosphere microbes, such as root-associated fungi, can improve plant access to soil resources, affecting plant health, productivity, and stress tolerance. While mycorrhizal associations are ubiquitous, plant-microbe interactions can be species specific. Here we show that the specificity of the effects of microbial symbionts on plant function can go beyond species level: colonization of roots by ectomycorrhizal fungi (EMF) of the genus Geopora has opposite effects on water uptake, and stomatal control of desiccation in drought tolerant and intolerant genotypes of pinyon pine (Pinus edulis Engelm.). These results demonstrate, for the first time, that microorganisms can have significant and opposite effects on important plant functional traits like stomatal control of desiccation that are associated with differential mortality and growth in nature. They also highlight that appropriate pairing of plant genotypes and microbial associates will be important for mitigating climate change impacts on vegetation.
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Affiliation(s)
- Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, MS J495, PO Box 1663, Los Alamos, NM, 87545, USA.
| | - Catherine A Gehring
- Department of Biological Sciences and Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Max G Ryan
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, MS J495, PO Box 1663, Los Alamos, NM, 87545, USA
- Integral Ecology Group, Duncan, BC, V9L 6H1, Canada
| | - Adair Patterson
- Department of Biological Sciences and Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Adrian S Losko
- Material Sciences and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
- Forschungs-Neutronenquelle Heinz Maier-Leibnitz, 85748, Garching, Germany
| | - Sven C Vogel
- Material Sciences and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Kelsey R Carter
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, MS J495, PO Box 1663, Los Alamos, NM, 87545, USA
| | - L Turin Dickman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, MS J495, PO Box 1663, Los Alamos, NM, 87545, USA
| | - Michelle A Espy
- Engineering Technology and Design Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Cheryl R Kuske
- Biosciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
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21
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Abdalla M, Bitterlich M, Jansa J, Püschel D, Ahmed MA. The role of arbuscular mycorrhizal symbiosis in improving plant water status under drought. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4808-4824. [PMID: 37409696 DOI: 10.1093/jxb/erad249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 06/28/2023] [Indexed: 07/07/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF) have been presumed to ameliorate crop tolerance to drought. Here, we review the role of AMF in maintaining water supply to plants from drying soils and the underlying biophysical mechanisms. We used a soil-plant hydraulic model to illustrate the impact of several AMF mechanisms on plant responses to edaphic drought. The AMF enhance the soil's capability to transport water and extend the effective root length, thereby attenuating the drop in matric potential at the root surface during soil drying. The synthesized evidence and the corresponding simulations demonstrate that symbiosis with AMF postpones the stress onset limit, which is defined as the disproportionality between transpiration rates and leaf water potentials, during soil drying. The symbiosis can thus help crops survive extended intervals of limited water availability. We also provide our perspective on future research needs and call for reconciling the dynamic changes in soil and root hydraulics in order to better understand the role of AMF in plant water relations in the face of climate changes.
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Affiliation(s)
- Mohanned Abdalla
- Chair of Root-Soil Interaction, School of Life Sciences, Technical University of Munich, Freising, Germany
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Department of Horticulture, Faculty of Agriculture, University of Khartoum, Khartoum North, Sudan
| | - Michael Bitterlich
- Humboldt-Universität zu Berlin, Thaer-Institute, Division Urban Plant Ecophysiology, Berlin, Germany
| | - Jan Jansa
- Laboratory of Fungal Biology, Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - David Püschel
- Department of Mycorrhizal Symbioses, Institute of Botany of the Czech Academy of Sciences, Průhonice, Czech Republic
| | - Mutez A Ahmed
- Chair of Root-Soil Interaction, School of Life Sciences, Technical University of Munich, Freising, Germany
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
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22
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Koehler T, Wankmüller FJP, Sadok W, Carminati A. Transpiration response to soil drying versus increasing vapor pressure deficit in crops: physical and physiological mechanisms and key plant traits. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4789-4807. [PMID: 37354081 PMCID: PMC10474596 DOI: 10.1093/jxb/erad221] [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: 02/09/2023] [Accepted: 06/07/2023] [Indexed: 06/26/2023]
Abstract
The water deficit experienced by crops is a function of atmospheric water demand (vapor pressure deficit) and soil water supply over the whole crop cycle. We summarize typical transpiration response patterns to soil and atmospheric drying and the sensitivity to plant hydraulic traits. We explain the transpiration response patterns using a soil-plant hydraulic framework. In both cases of drying, stomatal closure is triggered by limitations in soil-plant hydraulic conductance. However, traits impacting the transpiration response differ between the two drying processes and act at different time scales. A low plant hydraulic conductance triggers an earlier restriction in transpiration during increasing vapor pressure deficit. During soil drying, the impact of the plant hydraulic conductance is less obvious. It is rather a decrease in the belowground hydraulic conductance (related to soil hydraulic properties and root length density) that is involved in transpiration down-regulation. The transpiration response to increasing vapor pressure deficit has a daily time scale. In the case of soil drying, it acts on a seasonal scale. Varieties that are conservative in water use on a daily scale may not be conservative over longer time scales (e.g. during soil drying). This potential independence of strategies needs to be considered in environment-specific breeding for yield-based drought tolerance.
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Affiliation(s)
- Tina Koehler
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Fabian J P Wankmüller
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
| | - Walid Sadok
- Agronomy and Plant Genetics, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, Twin Cities, MN, USA
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
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23
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Vadez V, Pilloni R, Grondin A, Hajjarpoor A, Belhouchette H, Brouziyne Y, Chehbouni G, Kharrou MH, Zitouna-Chebbi R, Mekki I, Molénat J, Jacob F, Bossuet J. Water use efficiency across scales: from genes to landscapes. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4770-4788. [PMID: 36779607 PMCID: PMC10474597 DOI: 10.1093/jxb/erad052] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
Water scarcity is already set to be one of the main issues of the 21st century, because of competing needs between civil, industrial, and agricultural use. Agriculture is currently the largest user of water, but its share is bound to decrease as societies develop and clearly it needs to become more water efficient. Improving water use efficiency (WUE) at the plant level is important, but translating this at the farm/landscape level presents considerable challenges. As we move up from the scale of cells, organs, and plants to more integrated scales such as plots, fields, farm systems, and landscapes, other factors such as trade-offs need to be considered to try to improve WUE. These include choices of crop variety/species, farm management practices, landscape design, infrastructure development, and ecosystem functions, where human decisions matter. This review is a cross-disciplinary attempt to analyse approaches to addressing WUE at these different scales, including definitions of the metrics of analysis and consideration of trade-offs. The equations we present in this perspectives paper use similar metrics across scales to make them easier to connect and are developed to highlight which levers, at different scales, can improve WUE. We also refer to models operating at these different scales to assess WUE. While our entry point is plants and crops, we scale up the analysis of WUE to farm systems and landscapes.
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Affiliation(s)
- Vincent Vadez
- French National Research Institute for Sustainable Development (IRD), UMR DIADE, University of Montpellier, 911 Av. Agropolis BP65401, 34394, Montpellier, France
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, 502 324, Telangana, India
- LMI LAPSE, CERAAS-ISRA, Thiès, Senegal
| | - Raphael Pilloni
- French National Research Institute for Sustainable Development (IRD), UMR DIADE, University of Montpellier, 911 Av. Agropolis BP65401, 34394, Montpellier, France
| | - Alexandre Grondin
- French National Research Institute for Sustainable Development (IRD), UMR DIADE, University of Montpellier, 911 Av. Agropolis BP65401, 34394, Montpellier, France
| | - Amir Hajjarpoor
- French National Research Institute for Sustainable Development (IRD), UMR DIADE, University of Montpellier, 911 Av. Agropolis BP65401, 34394, Montpellier, France
| | - Hatem Belhouchette
- ABSys, Université de Montpellier, CIHEAM-IAMM, CIRAD, INRAE, Institut Agro, Montpellier, France
| | - Youssef Brouziyne
- International Water Management Institute (IWMI), MENA Office, Giza 12661, Egypt
| | - Ghani Chehbouni
- International Water Research Institute (IWRI), Mohammed VI Polytechnic University (UM6P) UMR CESBIO, Benguerir 43150, Morocco
| | - Mohamed Hakim Kharrou
- International Water Research Institute (IWRI), Mohammed VI Polytechnic University (UM6P) UMR CESBIO, Benguerir 43150, Morocco
| | | | - Insaf Mekki
- INRGREF, Carthage University, B.P. 10, 2080 Ariana, Tunisia
| | - Jérôme Molénat
- UMR LISAH, Université de Montpellier, INRAE, IRD, Institut Agro Montpellier, AgroParisTech, Montpellier, France
| | - Frédéric Jacob
- UMR LISAH, Université de Montpellier, INRAE, IRD, Institut Agro Montpellier, AgroParisTech, Montpellier, France
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24
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Martínez-Vilalta J, Poyatos R. Connecting the dots: concurrent assessment of water flows and pools to better understand plant responses to drought. TREE PHYSIOLOGY 2023; 43:1285-1289. [PMID: 37341378 DOI: 10.1093/treephys/tpad076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/08/2023] [Accepted: 06/15/2023] [Indexed: 06/22/2023]
Affiliation(s)
- Jordi Martínez-Vilalta
- CREAF, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma de Barcelona, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
| | - Rafael Poyatos
- CREAF, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma de Barcelona, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
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25
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de Oliveira JPV, Duarte VP, de Castro EM, Magalhães PC, Pereira FJ. Contrasting leaf intercellular space development in sorghum and maize modulates different tolerance capacity to water limitation. JOURNAL OF PLANT RESEARCH 2023; 136:535-548. [PMID: 37103629 DOI: 10.1007/s10265-023-01463-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 04/18/2023] [Indexed: 06/09/2023]
Abstract
The objective of this study was to evaluate the relationship between intercellular spaces and leaf gas exchange and the effect of total intercellular space on the growth of maize and sorghum under water restriction. The experiments were conducted in a greenhouse in a 2 × 3 factorial arrangement (two plant types and three water conditions: field capacity (FC = 100%), 75%FC, and 50%FC) with 10 replicates. The lack of water was a limiting factor for maize because it showed reductions in leaf area, leaf thickness, biomass, and gas exchange parameters, while sorghum remained unchanged, maintaining its water-use efficiency. This maintenance was correlated with the growth of intercellular spaces in sorghum leaves because the increased internal volume led to better CO2 control and prevented excessive water loss under drought stress. In addition, sorghum had more stomata than maize. These characteristics contributed to the drought tolerance of sorghum, while maize could not make the same adjustments. Therefore, changes in intercellular spaces promoted adjustments to avoid water loss and may have improved CO2 diffusion, characteristics that are important for drought-tolerant plants.
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Affiliation(s)
| | | | | | | | - Fabricio José Pereira
- Universidade Federal de Alfenas, Alfenas, MG, Rua Gabriel Monteiro da Silva, 700, Centro, Brazil.
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26
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Müllers Y, Postma JA, Poorter H, van Dusschoten D. Deep-water uptake under drought improved due to locally increased root conductivity in maize, but not in faba bean. PLANT, CELL & ENVIRONMENT 2023; 46:2046-2060. [PMID: 36942406 DOI: 10.1111/pce.14587] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/16/2023] [Accepted: 03/19/2023] [Indexed: 06/08/2023]
Abstract
Moderate soil drying can cause a strong decrease in the soil-root system conductance. The resulting impact on root water uptake depends on the spatial distribution of the altered conductance relatively to remaining soil water resources, which is largely unknown. Here, we analyzed the vertical distribution of conductance across root systems using a novel, noninvasive sensor technology on pot-grown faba bean and maize plants. Withholding water for 4 days strongly enhanced the vertical gradient in soil water potential. Therefore, roots in upper and deeper soil layers were affected differently: In drier, upper layers, root conductance decreased by 66%-72%, causing an amplification of the drop in leaf water potential. In wetter, deeper layers, root conductance increased in maize but not in faba bean. The consequently facilitated deep-water uptake in maize contributed up to 21% of total water uptake at the end of the measurement. Analysis of root length distributions with MRI indicated that the locally increased conductance was mainly caused by an increased intrinsic conductivity and not by additional root growth. Our findings show that plants can partly compensate for a reduced root conductance in upper, drier soil layers by locally increasing root conductivity in wetter layers, thereby improving deep-water uptake.
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Affiliation(s)
- Yannik Müllers
- IBG-2, Plant Sciences, Forschungszentrum Jülich, Jülich, Germany
| | | | - Hendrik Poorter
- IBG-2, Plant Sciences, Forschungszentrum Jülich, Jülich, Germany
- Department of Natural Sciences, Macquarie University, Sydney, Australia
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27
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Yang W, Zhu J, van Leeuwen C, Dai Z, Gambetta GA. GrapevineXL reliably predicts multi-annual dynamics of vine water status, berry growth, and sugar accumulation in vineyards. HORTICULTURE RESEARCH 2023; 10:uhad071. [PMID: 37293532 PMCID: PMC10244804 DOI: 10.1093/hr/uhad071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Accepted: 04/08/2023] [Indexed: 06/10/2023]
Abstract
Climate and water availability greatly affect each season's grape yield and quality. Using models to accurately predict environment impacts on fruit productivity and quality is a huge challenge. We calibrated and validated the functional-structural model, GrapevineXL, with a data set including grapevine seasonal midday stem water potential (Ψxylem), berry dry weight (DW), fresh weight (FW), and sugar concentration per volume ([Sugar]) for a wine grape cultivar (Vitis vinifera cv. Cabernet Franc) in field conditions over 13 years in Bordeaux, France. Our results showed that the model could make a fair prediction of seasonal Ψxylem and good-to-excellent predictions of berry DW, FW, [Sugar] and leaf gas exchange responses to predawn and midday leaf water potentials under diverse environmental conditions with 14 key parameters. By running virtual experiments to mimic climate change, an advanced veraison (i.e. the onset of ripening) of 14 and 28 days led to significant decreases of berry FW by 2.70% and 3.22%, clear increases of berry [Sugar] by 2.90% and 4.29%, and shortened ripening duration in 8 out of 13 simulated years, respectively. Moreover, the impact of the advanced veraison varied with seasonal patterns of climate and soil water availability. Overall, the results showed that the GrapevineXL model can predict plant water use and berry growth in field conditions and could serve as a valuable tool for designing sustainable vineyard management strategies to cope with climate change.
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Affiliation(s)
- Weiwei Yang
- Beijing Key Laboratory of Grape Science and Enology and Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, China
- EGFV, Univ. Bordeaux, Bordeaux Sciences Agro, INRAE, ISVV, Villenave d'Ornon, 33882, France
- The Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization in Xinjiang Production and Construction Group, College of Agriculture, Shihezi University, Shihezi, 832000, China
| | - Junqi Zhu
- The New Zealand Institute for Plant & Food Research Limited, Blenheim 7201, New Zealand
| | - Cornelis van Leeuwen
- EGFV, Univ. Bordeaux, Bordeaux Sciences Agro, INRAE, ISVV, Villenave d'Ornon, 33882, France
| | | | - Gregory A Gambetta
- EGFV, Univ. Bordeaux, Bordeaux Sciences Agro, INRAE, ISVV, Villenave d'Ornon, 33882, France
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28
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Peters RL, Steppe K, Pappas C, Zweifel R, Babst F, Dietrich L, von Arx G, Poyatos R, Fonti M, Fonti P, Grossiord C, Gharun M, Buchmann N, Steger DN, Kahmen A. Daytime stomatal regulation in mature temperate trees prioritizes stem rehydration at night. THE NEW PHYTOLOGIST 2023. [PMID: 37235688 DOI: 10.1111/nph.18964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/16/2023] [Indexed: 05/28/2023]
Abstract
Trees remain sufficiently hydrated during drought by closing stomata and reducing canopy conductance (Gc ) in response to variations in atmospheric water demand and soil water availability. Thresholds that control the reduction of Gc are proposed to optimize hydraulic safety against carbon assimilation efficiency. However, the link between Gc and the ability of stem tissues to rehydrate at night remains unclear. We investigated whether species-specific Gc responses aim to prevent branch embolisms, or enable night-time stem rehydration, which is critical for turgor-dependent growth. For this, we used a unique combination of concurrent dendrometer, sap flow and leaf water potential measurements and collected branch-vulnerability curves of six common European tree species. Species-specific Gc reduction was weakly related to the water potentials at which 50% of branch xylem conductivity is lost (P50 ). Instead, we found a stronger relationship with stem rehydration. Species with a stronger Gc control were less effective at refilling stem-water storage as the soil dries, which appeared related to their xylem architecture. Our findings highlight the importance of stem rehydration for water-use regulation in mature trees, which likely relates to the maintenance of adequate stem turgor. We thus conclude that stem rehydration must complement the widely accepted safety-efficiency stomatal control paradigm.
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Affiliation(s)
- Richard L Peters
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000, Ghent, Belgium
- Forest Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
- Forest is Life, TERRA Teaching and Research Centre, Gembloux Agro Bio-Tech, University of Liège, Passage des Déportés 2, 5030, Gembloux, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000, Ghent, Belgium
| | - Christoforos Pappas
- Department of Civil Engineering, University of Patras, Rio, Patras, 26504, Greece
| | - Roman Zweifel
- Forest Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Flurin Babst
- School of Natural Resources and the Environment, University of Arizona, East Lowell Street 1064, Tucson, AZ, 85721, USA
- Laboratory of Tree-Ring Research, University of Arizona, East Lowell Street 1215, Tucson, AZ, 857121, USA
| | - Lars Dietrich
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, CH-4056, Basel, Switzerland
| | - Georg von Arx
- Forest Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, 3012, Bern, Switzerland
| | - Rafael Poyatos
- CREAF, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma de Barcelona, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
| | - Marina Fonti
- Forest Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Patrick Fonti
- Forest Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Charlotte Grossiord
- Plant Ecology Research Laboratory PERL, School for Architecture, Civil and Environmental Engineering, EPFL, CH-1015, Lausanna, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape WSL, CH-1015, Lausanne, Switzerland
| | - Mana Gharun
- Department of Environmental Systems Science, ETH Zurich, Universitatstrasse 2, CH-8092, Zurich, Switzerland
- Department of Geosciences, University of Münster, Heisenbergstrasse 2, 48149, Münster, Germany
| | - Nina Buchmann
- Department of Environmental Systems Science, ETH Zurich, Universitatstrasse 2, CH-8092, Zurich, Switzerland
| | - David N Steger
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, CH-4056, Basel, Switzerland
| | - Ansgar Kahmen
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, CH-4056, Basel, Switzerland
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29
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Potkay A, Feng X. Do stomata optimize turgor-driven growth? A new framework for integrating stomata response with whole-plant hydraulics and carbon balance. THE NEW PHYTOLOGIST 2023; 238:506-528. [PMID: 36377138 DOI: 10.1111/nph.18620] [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: 06/24/2022] [Accepted: 11/11/2022] [Indexed: 06/16/2023]
Abstract
Every existing optimal stomatal model uses photosynthetic carbon assimilation as a proxy for plant evolutionary fitness. However, assimilation and growth are often decoupled, making assimilation less ideal for representing fitness when optimizing stomatal conductance to water vapor and carbon dioxide. Instead, growth should be considered a closer proxy for fitness. We hypothesize stomata have evolved to maximize turgor-driven growth, instead of assimilation, over entire plants' lifetimes, improving their abilities to compete and reproduce. We develop a stomata model that dynamically maximizes whole-stem growth following principles from turgor-driven growth models. Stomata open to assimilate carbohydrates that supply growth and osmotically generate turgor, while stomata close to prevent losses of turgor and growth due to negative water potentials. In steady state, the growth optimization model captures realistic stomatal, growth, and carbohydrate responses to environmental cues, reconciles conflicting interpretations within existing stomatal optimization theories, and explains patterns of carbohydrate storage and xylem conductance observed during and after drought. Our growth optimization hypothesis introduces a new paradigm for stomatal optimization models, elevates the role of whole-plant carbon use and carbon storage in stomatal functioning, and has the potential to simultaneously predict gross productivity, net productivity, and plant mortality through a single, consistent modeling framework.
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Affiliation(s)
- Aaron Potkay
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
- Saint Anthony Falls Laboratory, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
| | - Xue Feng
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
- Saint Anthony Falls Laboratory, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
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30
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Abdalla M, Schweiger AH, Berauer BJ, McAdam SAM, Ahmed MA. Constant hydraulic supply and ABA dynamics facilitate the trade-offs in water and carbon. FRONTIERS IN PLANT SCIENCE 2023; 14:1140938. [PMID: 37008480 PMCID: PMC10064056 DOI: 10.3389/fpls.2023.1140938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 03/03/2023] [Indexed: 06/19/2023]
Abstract
Carbon-water trade-offs in plants are adjusted through stomatal regulation. Stomatal opening enables carbon uptake and plant growth, whereas plants circumvent drought by closing stomata. The specific effects of leaf position and age on stomatal behavior remain largely unknown, especially under edaphic and atmospheric drought. Here, we compared stomatal conductance (gs ) across the canopy of tomato during soil drying. We measured gas exchange, foliage ABA level and soil-plant hydraulics under increasing vapor pressure deficit (VPD). Our results indicate a strong effect of canopy position on stomatal behavior, especially under hydrated soil conditions and relatively low VPD. In wet soil (soil water potential > -50 kPa), upper canopy leaves had the highest gs (0.727 ± 0.154 mol m-2 s-1) and assimilation rate (A; 23.4 ± 3.9 µmol m-2 s-1) compared to the leaves at a medium height of the canopy (gs : 0.159 ± 0.060 mol m2 s-1; A: 15.9 ± 3.8 µmol m-2 s-1). Under increasing VPD (from 1.8 to 2.6 kPa), gs , A and transpiration were initially impacted by leaf position rather than leaf age. However, under high VPD (2.6 kPa), age effect outweighed position effect. The soil-leaf hydraulic conductance was similar in all leaves. Foliage ABA levels increased with rising VPD in mature leaves at medium height (217.56 ± 85 ng g-1 FW) compared to upper canopy leaves (85.36 ± 34 ng g-1 FW). Under soil drought (< -50 kPa), stomata closed in all leaves resulting in no differences in gs across the canopy. We conclude that constant hydraulic supply and ABA dynamics facilitate preferential stomatal behavior and carbon-water trade-offs across the canopy. These findings are fundamental in understanding variations within the canopy, which helps in engineering future crops, especially in the face of climate change.
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Affiliation(s)
- Mohanned Abdalla
- Department of Land, Air and Water Resources, University of California Davis, Davis, CA, United States
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Department of Horticulture, Faculty of Agriculture, University of Khartoum, Khartoum North, Sudan
- Chair of Soil-Root Interactions, TUM School of Life Science, Technical University of Munich, Freising, Germany
| | - Andreas H. Schweiger
- Institute of Landscape and Plant Ecology, Department of Plant Ecology, University of Hohenheim, Stuttgart, Germany
| | - Bernd J. Berauer
- Institute of Landscape and Plant Ecology, Department of Plant Ecology, University of Hohenheim, Stuttgart, Germany
| | - Scott A. M. McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, United States
| | - Mutez Ali Ahmed
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Chair of Soil-Root Interactions, TUM School of Life Science, Technical University of Munich, Freising, Germany
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Wang X, Fan Y, Zhang C, Zhao Y, Du G, Li M, Si B. From comfort zone to mortality: Sequence of physiological stress thresholds in Robinia pseudoacacia seedlings during progressive drought. FRONTIERS IN PLANT SCIENCE 2023; 14:1149760. [PMID: 37008484 PMCID: PMC10060868 DOI: 10.3389/fpls.2023.1149760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 02/27/2023] [Indexed: 06/19/2023]
Abstract
INTRODUCTION Parameterizing the process of trees from the comfort zone to mortality during progressive drought is important for, but is not well represented in, vegetation models, given the lack of appropriate indices to gauge the response of trees to droughts. The objective of this study was to determine reliable and readily available tree drought stressindices and the thresholds at which droughts activate important physiological responses. METHODS We analyzed the changes in the transpiration (T), stomatal conductance, xylem conductance, and leaf health status due to a decrease in soil water availability (SWA), predawn xylem water potential (ψpd), and midday xylem water potential (ψmd) in Robinia pseudoacacia seedlings during progressive drought. RESULTS The results showed that ψmd was a better indicator of drought stress than SWA and ψpd, because ψmd was more closely related to the physiological response (defoliation and xylem embolization) during severe drought and could be measured more conveniently. We derived the following five stress levels from the observed responses to decreasing ψmd: comfort zone (ψmd > -0.9 MPa), wherein transpiration and stomatal conductance are not limited by SWA; moderate drought stress (-0.9 to -1.75 MPa), wherein transpiration and stomatal conductance are limited by drought; high drought stress (-1.75 to -2.59 MPa), wherein transpiration decreases significantly (T< 10%) and stomata closes completely; severe drought stress (-2.59 to -4.02 MPa), wherein transpiration ceases (T< 0.1%) and leaf shedding orwilting is > 50%; and extreme drought stress (< -4.02 MPa), leading to tree mortality due to xylem hydraulic failure. DISCUSSION To our knowledge, our scheme is the first to outline the quantitative thresholds for the downregulation of physiological processes in R. pseudoacacia during drought, therefore, can be used to synthesize valuable information for process-based vegetation models.
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Affiliation(s)
- Xia Wang
- College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, China
| | - Yanli Fan
- College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, China
| | - Congcong Zhang
- College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, China
| | - Yihong Zhao
- College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, China
| | - Guangyuan Du
- College of Science, Northwest A&F University, Yangling, China
| | - Min Li
- College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, China
| | - Bingcheng Si
- College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, China
- Department of Soil Science, University of Saskatchewan, Saskatoon, SK, Canada
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Zheng C, Bochmann H, Liu Z, Kant J, Schrey SD, Wojciechowski T, Postma JA. Plant root plasticity during drought and recovery: What do we know and where to go? FRONTIERS IN PLANT SCIENCE 2023; 14:1084355. [PMID: 37008469 PMCID: PMC10061088 DOI: 10.3389/fpls.2023.1084355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 02/28/2023] [Indexed: 06/19/2023]
Abstract
AIMS Drought stress is one of the most limiting factors for agriculture and ecosystem productivity. Climate change exacerbates this threat by inducing increasingly intense and frequent drought events. Root plasticity during both drought and post-drought recovery is regarded as fundamental to understanding plant climate resilience and maximizing production. We mapped the different research areas and trends that focus on the role of roots in plant response to drought and rewatering and asked if important topics were overlooked. METHODS We performed a comprehensive bibliometric analysis based on journal articles indexed in the Web of Science platform from 1900-2022. We evaluated a) research areas and temporal evolution of keyword frequencies, b) temporal evolution and scientific mapping of the outputs over time, c) trends in the research topics analysis, d) marked journals and citation analysis, and e) competitive countries and dominant institutions to understand the temporal trends of root plasticity during both drought and recovery in the past 120 years. RESULTS Plant physiological factors, especially in the aboveground part (such as "photosynthesis", "gas-exchange", "abscisic-acid") in model plants Arabidopsis, crops such as wheat and maize, and trees were found to be the most popular study areas; they were also combined with other abiotic factors such as salinity, nitrogen, and climate change, while dynamic root growth and root system architecture responses received less attention. Co-occurrence network analysis showed that three clusters were classified for the keywords including 1) photosynthesis response; 2) physiological traits tolerance (e.g. abscisic acid); 3) root hydraulic transport. Thematically, themes evolved from classical agricultural and ecological research via molecular physiology to root plasticity during drought and recovery. The most productive (number of publications) and cited countries and institutions were situated on drylands in the USA, China, and Australia. In the past decades, scientists approached the topic mostly from a soil-plant hydraulic perspective and strongly focused on aboveground physiological regulation, whereas the actual belowground processes seemed to have been the elephant in the room. There is a strong need for better investigation into root and rhizosphere traits during drought and recovery using novel root phenotyping methods and mathematical modeling.
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Affiliation(s)
- Congcong Zheng
- Institute of Bio- and Geosciences – Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, Jülich, Germany
- Faculty of Agriculture, University of Bonn, Bonn, Germany
| | - Helena Bochmann
- Institute of Bio- and Geosciences – Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, Jülich, Germany
- Faculty of Agriculture, University of Bonn, Bonn, Germany
| | - Zhaogang Liu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Josefine Kant
- Institute of Bio- and Geosciences – Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Silvia D. Schrey
- Institute of Bio- and Geosciences – Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Tobias Wojciechowski
- Institute of Bio- and Geosciences – Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Johannes Auke Postma
- Institute of Bio- and Geosciences – Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, Jülich, Germany
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Azzarà M, Abate E, Chiofalo MT, Crisafulli A, Trifilò P. Delaying drought-driven leaf cell damage may be the key trait of invasive trees ensuring their success in the Mediterranean basin. TREE PHYSIOLOGY 2023; 43:430-440. [PMID: 36413098 DOI: 10.1093/treephys/tpac134] [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: 06/18/2022] [Revised: 10/25/2022] [Accepted: 11/16/2022] [Indexed: 05/03/2023]
Abstract
Invasive alien species (IAS) threaten the biodiversity richness of the Mediterranean basin, a drought-prone region. However, our knowledge on the adaptive strategies of IAS for facing Mediterranean drought summers is still incomplete. The aim of the present study is to compare the water relations and the critical relative water content (RWC) values leading to loss of cell rehydration capacity of two Mediterranean basin IAS (i.e., Ailanthus altissima (Mill.) Swingle and Robinia pseudoacacia L.) versus two co-occurring native species (i.e., Fraxinus ornus L. and Quercus pubescens Willd.). Study IAS showed higher values of water potential at turgor loss point and osmotic potential at full turgor, lower values of modulus of elasticity and leaf mass area but higher photosynthesis rate, even during the summer, with respect to the Mediterranean native species. These findings supported the hypothesis that IAS are characterized by a resource acquisitive strategy coupled with a safety-efficiency trade-off, compared with Mediterranean native species. However, similar leaf RWC thresholds leading to loss of cell rehydration capacity were recorded in the two groups of species. Moreover, IAS showed higher saturated water content and capacitance values compared with the co-occurring species. Overall, our results suggest that the success of Mediterranean IAS is driven by their ability to delay dehydration damage of mesophyll cells during Mediterranean summer drought, thereby supporting their distinctive high carbon assimilation rate.
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Affiliation(s)
- Maria Azzarà
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, salita F. Stagno D'Alcontres 31, Messina 98166, Italy
| | - Elisa Abate
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, salita F. Stagno D'Alcontres 31, Messina 98166, Italy
| | - Maria T Chiofalo
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, salita F. Stagno D'Alcontres 31, Messina 98166, Italy
| | - Alessandro Crisafulli
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, salita F. Stagno D'Alcontres 31, Messina 98166, Italy
| | - Patrizia Trifilò
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, salita F. Stagno D'Alcontres 31, Messina 98166, Italy
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Koehler T, Schaum C, Tung SY, Steiner F, Tyborski N, Wild AJ, Akale A, Pausch J, Lueders T, Wolfrum S, Mueller CW, Vidal A, Vahl WK, Groth J, Eder B, Ahmed MA, Carminati A. Above and belowground traits impacting transpiration decline during soil drying in 48 maize (Zea mays) genotypes. ANNALS OF BOTANY 2023; 131:373-386. [PMID: 36479887 PMCID: PMC9992933 DOI: 10.1093/aob/mcac147] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 11/24/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND AIMS Stomatal regulation allows plants to promptly respond to water stress. However, our understanding of the impact of above and belowground hydraulic traits on stomatal regulation remains incomplete. The objective of this study was to investigate how key plant hydraulic traits impact transpiration of maize during soil drying. We hypothesize that the stomatal response to soil drying is related to a loss in soil hydraulic conductivity at the root-soil interface, which in turn depends on plant hydraulic traits. METHODS We investigate the response of 48 contrasting maize (Zea mays) genotypes to soil drying, utilizing a novel phenotyping facility. In this context, we measure the relationship between leaf water potential, soil water potential, soil water content and transpiration, as well as root, rhizosphere and aboveground plant traits. KEY RESULTS Genotypes differed in their responsiveness to soil drying. The critical soil water potential at which plants started decreasing transpiration was related to a combination of above and belowground traits: genotypes with a higher maximum transpiration and plant hydraulic conductance as well as a smaller root and rhizosphere system closed stomata at less negative soil water potentials. CONCLUSIONS Our results demonstrate the importance of belowground hydraulics for stomatal regulation and hence drought responsiveness during soil drying. Furthermore, this finding supports the hypothesis that stomata start to close when soil hydraulic conductivity drops at the root-soil interface.
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Affiliation(s)
| | - Carolin Schaum
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Shu-Yin Tung
- Institute for Agroecology and Organic Farming, Bavarian State Research Center for Agriculture, Freising, Germany
| | | | - Nicolas Tyborski
- Ecological Microbiology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Andreas J Wild
- Agroecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Asegidew Akale
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Johanna Pausch
- Agroecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Tillmann Lueders
- Ecological Microbiology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Sebastian Wolfrum
- Institute for Agroecology and Organic Farming, Bavarian State Research Center for Agriculture, Freising, Germany
| | - Carsten W Mueller
- Soil Science, Technical University of Munich, Freising, Germany
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - Alix Vidal
- Soil Biology Group, Wageningen University & Research, Wageningen, The Netherlands
| | - Wouter K Vahl
- Institute for Crop Science and Plant Breeding, Bavarian State Research Center for Agriculture, Freising, Germany
| | - Jennifer Groth
- Institute for Crop Science and Plant Breeding, Bavarian State Research Center for Agriculture, Freising, Germany
| | - Barbara Eder
- Institute for Crop Science and Plant Breeding, Bavarian State Research Center for Agriculture, Freising, Germany
| | - Mutez A Ahmed
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Department of Land, Air and Water Resources, University of California Davis, Davis, CA, USA
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
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Cai G, Wankmüller F, Ahmed MA, Carminati A. How the interactions between atmospheric and soil drought affect the functionality of plant hydraulics. PLANT, CELL & ENVIRONMENT 2023; 46:733-735. [PMID: 36624562 PMCID: PMC10108313 DOI: 10.1111/pce.14538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Affiliation(s)
- Gaochao Cai
- School of AgricultureShenzhen Campus of Sun Yat‐sen UniversityShenzhenP.R. China
| | - Fabian Wankmüller
- Department of Environmental Systems ScienceETH ZürichZürichSwitzerland
| | - Mutez A. Ahmed
- Department of Land, Air and Water Resources, Soil‐Plant InteractionsUniversity of California DavisDavisCaliforniaUSA
| | - Andrea Carminati
- Department of Environmental Systems ScienceETH ZürichZürichSwitzerland
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Bucci SJ, Carbonell-Silletta L, Cavallaro A, Arias NS, Campanello PI, Goldstein G, Scholz FG. Bark and sapwood water storage and the atypical pattern of recharge and discharge of water reservoirs indicate low vulnerability to drought in Araucaria araucana. TREE PHYSIOLOGY 2023; 43:248-261. [PMID: 36209429 DOI: 10.1093/treephys/tpac113] [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: 08/13/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
Stored water in inner tissues influences the plant water economy, which might be particularly relevant for trees facing increasing dry conditions due to climate change. We studied the water storage in the inner bark and the sapwood of Araucaria araucana (Molina) K. Koch. This species has an extremely thick inner bark and thus it can be used as a model system to assess the impact of internal water storage on plant water balance. Specifically, we analyzed the water circulation pathways in and out of the elastic water storages by using simultaneously frequency domain moisture sensors and dendrometers inserted in the inner bark and in the sapwood, and sap flow determinations during the dry season. The daily patterns of water content and expansion and contraction of the stem tissues were similar to the sap flow pattern. The whole-stem water content and diameter increased in the morning and decreased in the afternoon, contrary to the typical pattern observed in most tree species. An osmotic gradient favoring the water influx from sapwood to inner bark was observed in the morning. There were no lags in the onset of sap flow between different stem heights at the time that recharge of reservoirs occurred. Sap flow at 6 m height was higher than basal sap flow in the afternoon, when the sapwood water content started to decline followed by the water content of the inner bark. Inner bark and sapwood contributed 5-11% to total daily transpiration, allowing the maintenance of high water potentials in the dry season. Our results suggest that the stored water in the stems, the atypical dynamic of recharge and discharge of water from reservoirs and the high tissue capacitance may make an important contribution to the survival of A. araucana during drought periods by maintaining the water balance.
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Affiliation(s)
- Sandra Janet Bucci
- Grupo de Estudios Biofísicos y Ecofisiológicos (GEBEF), Instituto de Biociencias de la Patagonia (INBIOP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), 9000 Comodoro Rivadavia, Argentina
- Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), 9000 Comodoro Rivadavia, Argentina
| | - Luisina Carbonell-Silletta
- Grupo de Estudios Biofísicos y Ecofisiológicos (GEBEF), Instituto de Biociencias de la Patagonia (INBIOP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), 9000 Comodoro Rivadavia, Argentina
- Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), 9000 Comodoro Rivadavia, Argentina
| | - Agustin Cavallaro
- Grupo de Estudios Biofísicos y Ecofisiológicos (GEBEF), Instituto de Biociencias de la Patagonia (INBIOP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), 9000 Comodoro Rivadavia, Argentina
- Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), 9000 Comodoro Rivadavia, Argentina
| | - Nadia Soledad Arias
- Grupo de Estudios Biofísicos y Ecofisiológicos (GEBEF), Instituto de Biociencias de la Patagonia (INBIOP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), 9000 Comodoro Rivadavia, Argentina
- Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), 9000 Comodoro Rivadavia, Argentina
| | - Paula Inés Campanello
- CONICET and Departamento de Ingeniería Forestal, Facultad de Ingeniería, UNPSJB, Esquel U9200, Argentina
| | - Guillermo Goldstein
- Instituto de Ecología, Genética y Evolución de Buenos Aires. UBA-CONICET, Buenos Aires 1425, Argentina
- University of Miami, Coral Gables, FL 33124, USA
| | - Fabián Gustavo Scholz
- Grupo de Estudios Biofísicos y Ecofisiológicos (GEBEF), Instituto de Biociencias de la Patagonia (INBIOP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), 9000 Comodoro Rivadavia, Argentina
- Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), 9000 Comodoro Rivadavia, Argentina
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Juenger TE, Verslues PE. Time for a drought experiment: Do you know your plants' water status? THE PLANT CELL 2023; 35:10-23. [PMID: 36346190 PMCID: PMC9806650 DOI: 10.1093/plcell/koac324] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Drought stress is an increasing concern because of climate change and increasing demands on water for agriculture. There are still many unknowns about how plants sense and respond to water limitation, including which genes and cellular mechanisms are impactful for ecology and crop improvement in drought-prone environments. A better understanding of plant drought resistance will require integration of several research disciplines. A common set of parameters to describe plant water status and quantify drought severity can enhance data interpretation and research integration across the research disciplines involved in understanding drought resistance and would be especially useful in integrating the flood of genomic data being generated in drought studies. Water potential (ψw) is a physical measure of the free energy status of water that, along with related physiological measurements, allows unambiguous description of plant water status that can apply across various soil types and environmental conditions. ψw and related physiological parameters can be measured with relatively modest investment in equipment and effort. Thus, we propose that increased use of ψw as a fundamental descriptor of plant water status can enhance the insight gained from many drought-related experiments and facilitate data integration and sharing across laboratories and research disciplines.
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Trifilò P, Abate E, Petruzzellis F, Azzarà M, Nardini A. Critical water contents at leaf, stem and root level leading to irreversible drought-induced damage in two woody and one herbaceous species. PLANT, CELL & ENVIRONMENT 2023; 46:119-132. [PMID: 36266962 DOI: 10.1111/pce.14469] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/11/2022] [Accepted: 10/16/2022] [Indexed: 06/16/2023]
Abstract
Plant water content is a simple and promising parameter for monitoring drought-driven plant mortality risk. However, critical water content thresholds leading to cell damage and plant failure are still unknown. Moreover, it is unclear whether whole-plant or a specific organ water content is the most reliable indicator of mortality risk. We assessed differences in dehydration thresholds in leaf, stem and root samples, hampering the organ-specific rehydration capacity and increasing the mortality risk. We also tested eventual differences between a fast experimental dehydration of uprooted plants, compared to long-term water stress induced by withholding irrigation in potted plants. We investigated three species with different growth forms and leaf habits i.e., Helianthus annuus (herbaceous), Populus nigra (deciduous tree) and Quercus ilex (evergreen tree). Results obtained by the two dehydration treatments largely overlapped, thus validating bench dehydration as a fast but reliable method to assess species-specific critical water content thresholds. Regardless of the organ considered, a relative water content value of 60% induced significant cell membrane damage and loss of rehydration capacity, thus leading to irreversible plant failure and death.
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Affiliation(s)
- Patrizia Trifilò
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, Messina, Italy
| | - Elisa Abate
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, Messina, Italy
| | | | - Maria Azzarà
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, Messina, Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Trieste, Italy
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Kahmen A, Basler D, Hoch G, Link RM, Schuldt B, Zahnd C, Arend M. Root water uptake depth determines the hydraulic vulnerability of temperate European tree species during the extreme 2018 drought. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1224-1239. [PMID: 36219537 DOI: 10.1111/plb.13476] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
We took advantage of the European 2018 drought and assessed the mechanisms causing differences in drought vulnerability among mature individuals of nine co-occurring tree species at the Swiss Canopy Crane II site in Switzerland. Throughout the drought we monitored leaf water status and determined native embolism formation in the canopy of the trees as indicators of drought vulnerability. We also determined hydraulic vulnerability thresholds (Ψ12 -, Ψ50 - and Ψ88 -values), corresponding hydraulic safety margins (HSMs) and carbohydrate reserves for all species as well as total average leaf area per tree, and used stable isotopes to assess differences in root water uptake depth among the nine species as variables predicting differences in drought vulnerability among species. Marked differences in drought vulnerability were observed among the nine tree species. Six species maintained their water potentials above hydraulic thresholds, while three species, Fagus sylvatica, Carpinus betulus and Picea abies, were pushed beyond their hydraulic thresholds and showed loss of hydraulic conductivity in their canopies at the end of the drought. Embolism resistance thresholds and associated HSMs did not explain why the co-existing species differed in their drought vulnerability, neither did their degree of isohydry, nor their regulation of carbohydrate reserves. Instead, differences in structural-morphological traits, in particular root water uptake depth, were associated with the risk of reaching hydraulic vulnerability thresholds and embolism formation among the nine species. Our study shows that structural-morphological traits, such as root water uptake depth, determine how quickly different species approach hydraulic vulnerability thresholds during a drought event and can thus explain species differences in drought vulnerability among mature field-grown trees.
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Affiliation(s)
- A Kahmen
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
| | - D Basler
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - G Hoch
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
| | - R M Link
- Ecophysiology and Vegetation Ecology, Universität Würzburg, Würzburg, Germany
| | - B Schuldt
- Ecophysiology and Vegetation Ecology, Universität Würzburg, Würzburg, Germany
| | - C Zahnd
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
| | - M Arend
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
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Guan X, Werner J, Cao KF, Pereira L, Kaack L, McAdam SAM, Jansen S. Stem and leaf xylem of angiosperm trees experiences minimal embolism in temperate forests during two consecutive summers with moderate drought. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1208-1223. [PMID: 34990084 DOI: 10.1111/plb.13384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Drought events may increase the likelihood that the plant water transport system becomes interrupted by embolism. Yet our knowledge about the temporal frequency of xylem embolism in the field is frequently lacking, as it requires detailed, long-term measurements. We measured xylem embolism resistance and midday xylem water potentials during the consecutive summers of 2019 and 2020 to estimate maximum levels of embolism in leaf and stem xylem of ten temperate angiosperm tree species. We also studied vessel and pit membrane characteristics based on light and electron microscopy to corroborate potential differences in embolism resistance between leaves and stems. Apart from A. pseudoplatanus and Q. petraea, eight species experienced minimum xylem water potentials that were close to or below those required to initiate embolism. Water potentials corresponding to ca. 12% loss of hydraulic conductivity (PLC) could occur in six species, while considerable levels of embolism around 50% PLC were limited to B. pendula and C. avellana. There was a general agreement in embolism resistance between stems and leaves, with leaves being equally or more resistant than stems. Also, xylem embolism resistance was significantly correlated to intervessel pit membrane thickness (TPM ) for stems, but not to vessel diameter and total intervessel pit membrane surface area of a vessel. Our data indicate that low amounts of embolism occur in most species during moderate summer drought, and that considerable levels of embolism are uncommon. Moreover, our experimental and TPM data show that leaf xylem is generally no more vulnerable than stem xylem.
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Affiliation(s)
- X Guan
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - J Werner
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - K-F Cao
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilisation of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - L Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - L Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - S A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
| | - S Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
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41
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Müllers Y, Postma JA, Poorter H, van Dusschoten D. Stomatal conductance tracks soil-to-leaf hydraulic conductance in faba bean and maize during soil drying. PLANT PHYSIOLOGY 2022; 190:2279-2294. [PMID: 36099023 PMCID: PMC9706430 DOI: 10.1093/plphys/kiac422] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 08/24/2022] [Indexed: 06/08/2023]
Abstract
Although regulation of stomatal conductance is widely assumed to be the most important plant response to soil drying, the picture is incomplete when hydraulic conductance from soil to the leaf, upstream of the stomata, is not considered. Here, we investigated to what extent soil drying reduces the conductance between soil and leaf, whether this reduction differs between species, how it affects stomatal regulation, and where in the hydraulic pathway it occurs. To this end, we noninvasively and continuously measured the total root water uptake rate, soil water potential, leaf water potential, and stomatal conductance of 4-week-old, pot-grown maize (Zea mays) and faba bean (Vicia faba) plants during 4 days of water restriction. In both species, the soil-plant conductance, excluding stomatal conductance, declined exponentially with soil drying and was reduced to 50% above a soil water potential of -0.1 MPa, which is far from the permanent wilting point. This loss of conductance has immediate consequences for leaf water potential and the associated stomatal regulation. Both stomatal conductance and soil-plant conductance declined at a higher rate in faba bean than in maize. Estimations of the water potential at the root surface and an incomplete recovery 22 h after rewatering indicate that the loss of conductance, at least partly, occurred inside the plants, for example, through root suberization or altered aquaporin gene expression. Our findings suggest that differences in the stomatal sensitivity among plant species are partly explained by the sensitivity of root hydraulic conductance to soil drying.
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Affiliation(s)
- Yannik Müllers
- Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Johannes A Postma
- Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Hendrik Poorter
- Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109 Australia
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Joshi J, Stocker BD, Hofhansl F, Zhou S, Dieckmann U, Prentice IC. Towards a unified theory of plant photosynthesis and hydraulics. NATURE PLANTS 2022; 8:1304-1316. [PMID: 36303010 PMCID: PMC9663302 DOI: 10.1038/s41477-022-01244-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 08/04/2022] [Indexed: 06/01/2023]
Abstract
The global carbon and water cycles are governed by the coupling of CO2 and water vapour exchanges through the leaves of terrestrial plants, controlled by plant adaptations to balance carbon gains and hydraulic risks. We introduce a trait-based optimality theory that unifies the treatment of stomatal responses and biochemical acclimation of plants to environments changing on multiple timescales. Tested with experimental data from 18 species, our model successfully predicts the simultaneous decline in carbon assimilation rate, stomatal conductance and photosynthetic capacity during progressive soil drought. It also correctly predicts the dependencies of gas exchange on atmospheric vapour pressure deficit, temperature and CO2. Model predictions are also consistent with widely observed empirical patterns, such as the distribution of hydraulic strategies. Our unified theory opens new avenues for reliably modelling the interactive effects of drying soil and rising atmospheric CO2 on global photosynthesis and transpiration.
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Affiliation(s)
- Jaideep Joshi
- Advancing Systems Analysis Program, International Institute for Applied Systems Analysis, Laxenburg, Austria.
- Divecha Centre for Climate Change, Indian Institute of Science, Bengaluru, India.
- Complexity Science and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.
| | - Benjamin D Stocker
- Department of Environmental Systems Science, ETH, Universitätsstrasse 2, Zürich, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Florian Hofhansl
- Biodiversity and Natural Resources Program, International Institute for Applied Systems Analysis, Laxenburg, Austria
| | - Shuangxi Zhou
- Department of Biological Sciences, Macquarie University, Macquarie Park, Australia
- CSIRO Agriculture and Food, Glen Osmond, South Australia, Australia
| | - Ulf Dieckmann
- Advancing Systems Analysis Program, International Institute for Applied Systems Analysis, Laxenburg, Austria
- Complexity Science and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- Department of Evolutionary Studies of Biosystems, The Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa, Japan
| | - Iain Colin Prentice
- Department of Biological Sciences, Macquarie University, Macquarie Park, Australia
- Department of Life Sciences, Georgina Mace Centre for the Living Planet, Imperial College London, Silwood Park Campus, Ascot, UK
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China
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Li H, Li L, Liu N, Liu Z, Lu Y, Shao L. Balanced below- and above-ground growth improved yield and water productivity by cultivar renewal for winter wheat. FRONTIERS IN PLANT SCIENCE 2022; 13:1022023. [PMID: 36388545 PMCID: PMC9659963 DOI: 10.3389/fpls.2022.1022023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
Breeding cultivars that can maintain high production and water productivity (WP) under various growing conditions would be important for mitigating freshwater shortage problems. Experiments were carried out to assess the changes in yield and WP of different cultivars by breeding and traits related to the changes using tubes with 1.05 m depth and 19.2 cm inner diameter buried in the field located in the North China Plain. Six winter wheat cultivars released from the 1970s to 2010s were assessed under three water levels for three seasons. The results indicated that yield was on average improved by 19.9% and WP by 21.5% under the three water levels for the three seasons for the cultivar released in the 2010s as compared with that released in the 1970s. The performance of the six cultivars was relatively stable across the experimental duration. The improvement in yield was mainly attributed to the maintenance of higher photosynthetic capacity during the reproductive growth stage and greater above-ground biomass accumulation. These improvements were larger under wet conditions than that under dry conditions, indicating that the yield potential was increased by cultivar renewal. Traits related to yield and WP improvements included the increased harvest index and reduced root: shoot ratio. New cultivars reduced the redundancy in root proliferation in the topsoil layer, which did not compromise the efficient utilization of soil moisture but reduced the metabolic input in root growth. Balanced above- and below-ground growth resulted in a significant improvement in root efficiency at grain yield level up to 40% from the cultivars released in the 1970s to those recently released. The results from this study indicated that the improved efficiency in both the above- and below-parts played important roles in enhancing crop production and resource use efficiency.
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Affiliation(s)
- Haotian Li
- Key Laboratory of Agricultural Water Resources, The Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, Shijiazhuang, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lu Li
- Key Laboratory of Agricultural Water Resources, The Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, Shijiazhuang, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Na Liu
- Key Laboratory of Agricultural Water Resources, The Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, Shijiazhuang, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zimeng Liu
- Key Laboratory of Agricultural Water Resources, The Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, Shijiazhuang, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yang Lu
- Key Laboratory of Agricultural Water Resources, The Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, Shijiazhuang, China
| | - Liwei Shao
- Key Laboratory of Agricultural Water Resources, The Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, Shijiazhuang, China
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Abdalla M, Ahmed MA, Cai G, Zarebanadkauki M, Carminati A. Coupled effects of soil drying and salinity on soil-plant hydraulics. PLANT PHYSIOLOGY 2022; 190:1228-1241. [PMID: 35579362 PMCID: PMC9516742 DOI: 10.1093/plphys/kiac229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/27/2022] [Indexed: 05/20/2023]
Abstract
Salinity and soil drying are expected to induce salt accumulation at the root-soil interface of transpiring plants. However, the consequences of this on the relationship between transpiration rate (E) and leaf xylem water potential (ψleaf-x) are yet to be quantified. Here, we used a noninvasive root pressure chamber to measure the E(ψleaf-x) relationship of tomato (Solanum lycopersicum L.) treated with (saline) or without 100-mM NaCl (nonsaline conditions). The results were reproduced and interpreted with a soil-plant hydraulic model. Under nonsaline conditions, the E(ψleaf-x) relationship became progressively more nonlinear as the soil dried (θ ≤ 0.13 cm3 cm-3, ψsoil = -0.08 MPa or less). Under saline conditions, plants exhibited an earlier nonlinearity in the E(ψleaf-x) relationship (θ ≤ 0.15 cm3 cm-3, ψsoil = -0.05 MPa or less). During soil drying, salinity induced a more negative ψleaf-x at predawn, reduced transpiration rate, and caused a reduction in root hydraulic conductance (from 1.48 × 10-6 to 1.30 × 10-6 cm3 s-1 hPa-1). The model suggested that the marked nonlinearity was caused by salt accumulation at the root surface and the consequential osmotic gradients. In dry soil, most water potential dissipation occurred in the bulk soil and rhizosphere rather than inside the plant. Under saline-dry conditions, the loss in osmotic potential at the root surface was the preeminent component of the total dissipation. The physical model of water flow and solute transport supports the hypothesis that a buildup of osmotic potential at the root-soil interface causes a large drop in ψleaf-x and limits transpiration rate under drought and salinity.
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Affiliation(s)
| | - Mutez Ali Ahmed
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Department of Land, Air and Water Resources, University of California Davis, Davis, California 95616, USA
| | - Gaochao Cai
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Mohsen Zarebanadkauki
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
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45
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Bourbia I, Lucani C, Brodribb TJ. Constant hydraulic supply enables optical monitoring of transpiration in a grass, a herb, and a conifer. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:5625-5633. [PMID: 35727898 PMCID: PMC9467656 DOI: 10.1093/jxb/erac241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
Plant transpiration is an inevitable consequence of photosynthesis and has a huge impact on the terrestrial carbon and water cycle, yet accurate and continuous monitoring of its dynamics is still challenging. Under well-watered conditions, canopy transpiration (Ec) could potentially be continuously calculated from stem water potential (Ψstem), but only if the root to stem hydraulic conductance (Kr-s) remains constant and plant capacitance is relatively small. We tested whether such an approach is viable by investigating whether Kr-s remains constant under a wide range of daytime transpiration rates in non-water-stressed plants. Optical dendrometers were used to continuously monitor tissue shrinkage, an accurate proxy of Ψstem, while Ec was manipulated in three species with contrasting morphological, anatomical, and phylogenetic identities: Tanacetum cinerariifolium, Zea mays, and Callitris rhomboidea. In all species, we found Kr-s to remain constant across a wide range of Ec, meaning that the dynamics of Ψstem could be used to monitor Ec. This was evidenced by the close agreement between measured Ec and that predicted from optically measured Ψstem. These results suggest that optical dendrometers enable both plant hydration and Ec to be monitored non-invasively and continuously in a range of woody and herbaceous species. This technique presents new opportunities to monitor transpiration under laboratory and field conditions in a diversity of woody, herbaceous, and grassy species.
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Affiliation(s)
- Ibrahim Bourbia
- School of Natural Sciences, University of Tasmania, Hobart, Tas, Australia
| | - Christopher Lucani
- School of Natural Sciences, University of Tasmania, Hobart, Tas, Australia
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46
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Oberleitner F, Hartmann H, Hasibeder R, Huang J, Losso A, Mayr S, Oberhuber W, Wieser G, Bahn M. Amplifying effects of recurrent drought on the dynamics of tree growth and water use in a subalpine forest. PLANT, CELL & ENVIRONMENT 2022; 45:2617-2635. [PMID: 35610775 DOI: 10.1111/pce.14369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 04/16/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
Despite recent advances in our understanding of drought impacts on tree functioning, we lack knowledge about the dynamic responses of mature trees to recurrent drought stress. At a subalpine forest site, we assessed the effects of three years of recurrent experimental summer drought on tree growth and water relations of Larix decidua Mill. and Picea abies (L. Karst.), two common European conifers representative for contrasting water-use strategies. We combined dendrometer and xylem sap flow measurements with analyses of xylem anatomy and non-structural carbohydrates and their carbon-isotope composition. Recurrent drought increased the effects of soil moisture limitation on growth and xylogenesis, and to a lesser extent on xylem sap flow. P. abies showed stronger growth responses to recurrent drought, reduced starch concentrations in branches and increased water-use efficiency when compared to L. decidua. Despite comparatively larger maximum tree water deficits than in P. abies, xylem formation of L. decidua was less affected by drought, suggesting a stronger capacity of rehydration or lower cambial turgor thresholds for growth. Our study shows that recurrent drought progressively increases impacts on mature trees of both species, which suggests that in a future climate increasing drought frequency could impose strong legacies on carbon and water dynamics of treeline species.
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Affiliation(s)
| | - Henrik Hartmann
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Roland Hasibeder
- Department of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Jianbei Huang
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Innsbruck, Austria
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Walter Oberhuber
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Gerhard Wieser
- Department of Botany, University of Innsbruck, Innsbruck, Austria
- Department of Alpine Timberline Ecophysiology, Federal Research and Training Centre for Forests, Natural Hazards and Landscape (BFW), Innsbruck, Austria
| | - Michael Bahn
- Department of Ecology, University of Innsbruck, Innsbruck, Austria
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47
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Shoaib M, Banerjee BP, Hayden M, Kant S. Roots’ Drought Adaptive Traits in Crop Improvement. PLANTS 2022; 11:plants11172256. [PMID: 36079644 PMCID: PMC9460784 DOI: 10.3390/plants11172256] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 08/26/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022]
Abstract
Drought is one of the biggest concerns in agriculture due to the projected reduction of global freshwater supply with a concurrent increase in global food demand. Roots can significantly contribute to improving drought adaptation and productivity. Plants increase water uptake by adjusting root architecture and cooperating with symbiotic soil microbes. Thus, emphasis has been given to root architectural responses and root–microbe relationships in drought-resilient crop development. However, root responses to drought adaptation are continuous and complex processes and involve additional root traits and interactions among themselves. This review comprehensively compiles and discusses several of these root traits such as structural, physiological, molecular, hydraulic, anatomical, and plasticity, which are important to consider together, with architectural changes, when developing drought resilient crop varieties. In addition, it describes the significance of root contribution in improving soil structure and water holding capacity and its implication on long-term resilience to drought. In addition, various drought adaptive root ideotypes of monocot and dicot crops are compared and proposed for given agroclimatic conditions. Overall, this review provides a broader perspective of understanding root structural, physiological, and molecular regulators, and describes the considerations for simultaneously integrating multiple traits for drought tolerance and crop improvement, under specific growing environments.
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Affiliation(s)
- Mirza Shoaib
- Agriculture Victoria, Grains Innovation Park, 110 Natimuk Road, Horsham, VIC 3400, Australia
- School of Applied Systems Biology, La Trobe University, Bundoora, Melbourne, VIC 3083, Australia
| | - Bikram P. Banerjee
- Agriculture Victoria, Grains Innovation Park, 110 Natimuk Road, Horsham, VIC 3400, Australia
| | - Matthew Hayden
- School of Applied Systems Biology, La Trobe University, Bundoora, Melbourne, VIC 3083, Australia
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, 5 Ring Road, Bundoora, Melbourne, VIC 3083, Australia
| | - Surya Kant
- Agriculture Victoria, Grains Innovation Park, 110 Natimuk Road, Horsham, VIC 3400, Australia
- School of Applied Systems Biology, La Trobe University, Bundoora, Melbourne, VIC 3083, Australia
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, 5 Ring Road, Bundoora, Melbourne, VIC 3083, Australia
- Correspondence:
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48
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Álvarez-Maldini C, Acevedo M, Estay D, Aros F, Dumroese RK, Sandoval S, Pinto M. Examining physiological, water relations, and hydraulic vulnerability traits to determine anisohydric and isohydric behavior in almond ( Prunus dulcis) cultivars: Implications for selecting agronomic cultivars under changing climate. FRONTIERS IN PLANT SCIENCE 2022; 13:974050. [PMID: 36092408 PMCID: PMC9453546 DOI: 10.3389/fpls.2022.974050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
The search for drought tolerant species or cultivars is important to address water scarcity caused by climate change in Mediterranean regions. The anisohydric-isohydric behavior concept has been widely used to describe stomatal regulation during drought, simply in terms of variation of minimal water potential (Ψmin) in relation to pre-dawn water potential (Ψpd). However, its simplicity has sometimes failed to deliver consistent results in describing a complex behavior that results from the coordination of several plant functional traits. While Prunus dulcis (almond) is known as a drought tolerant species, little information is available regarding consistent metrics to discriminate among cultivars or the mechanisms underlying drought tolerance in almond. Here we show a sequence of plant stomatal, hydraulic, and wilting responses to drought in almonds, and the main differences between anisohydric and isohydric cultivars. In a pot desiccation experiment we observed that stomatal closure in P. dulcis is not driven by loss in turgor or onset of xylem cavitation, but instead, occurs early in response to decreasing Ψmin that could be related to the protection of the integrity of the hydraulic system, independently of cultivar. Also, we report that anisohydric cultivars of P. dulcis are characterized by maximum stomatal conductance, lower water potentials for stomatal closure and turgor loss, and lower vulnerability to xylem cavitation, which are traits that correlated with metrics to discriminate anisohydric and isohydric behavior. Our results demonstrate that P. dulcis presents a strategy to avoid cavitation by closing stomata during the early stages of drought. Future research should also focus on below-ground hydraulic traits, which could trigger stomatal closure in almond.
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Affiliation(s)
- Carolina Álvarez-Maldini
- Instituto Ciencias Agroalimentarias Animales y Ambientales (ICA3), Campus Colchagua, Universidad de O′Higgins, San Fernando, Chile
| | - Manuel Acevedo
- Centro Tecnológico de la Planta Forestal, Instituto Forestal, Sede Biobío, San Pedro de la Paz, Chile
| | - Daniela Estay
- Instituto Ciencias Agroalimentarias Animales y Ambientales (ICA3), Campus Colchagua, Universidad de O′Higgins, San Fernando, Chile
| | - Fabián Aros
- Instituto Ciencias Agroalimentarias Animales y Ambientales (ICA3), Campus Colchagua, Universidad de O′Higgins, San Fernando, Chile
| | - R. Kasten Dumroese
- United States Department of Agriculture Forest Service, Rocky Mountain Research Station, Moscow, ID, United States
| | - Simón Sandoval
- Laboratorio de Análisis y Modelamiento de Geoinformación, Departamento de Manejo de Bosques y Medio Ambiente, Facultad de Ciencias Forestales, Universidad de Concepción, Concepción, Chile
| | - Manuel Pinto
- Instituto Ciencias Agroalimentarias Animales y Ambientales (ICA3), Campus Colchagua, Universidad de O′Higgins, San Fernando, Chile
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Johnson DM, Katul G, Domec J. Catastrophic hydraulic failure and tipping points in plants. PLANT, CELL & ENVIRONMENT 2022; 45:2231-2266. [PMID: 35394656 PMCID: PMC9544843 DOI: 10.1111/pce.14327] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/14/2022] [Accepted: 03/20/2022] [Indexed: 06/12/2023]
Abstract
Water inside plants forms a continuous chain from water in soils to the water evaporating from leaf surfaces. Failures in this chain result in reduced transpiration and photosynthesis and are caused by soil drying and/or cavitation-induced xylem embolism. Xylem embolism and plant hydraulic failure share several analogies to 'catastrophe theory' in dynamical systems. These catastrophes are often represented in the physiological and ecological literature as tipping points when control variables exogenous (e.g., soil water potential) or endogenous (e.g., leaf water potential) to the plant are allowed to vary on time scales much longer than time scales associated with cavitation events. Here, plant hydraulics viewed from the perspective of catastrophes at multiple spatial scales is considered with attention to bubble expansion within a xylem conduit, organ-scale vulnerability to embolism, and whole-plant biomass as a proxy for transpiration and hydraulic function. The hydraulic safety-efficiency tradeoff, hydraulic segmentation and maximum plant transpiration are examined using this framework. Underlying mechanisms for hydraulic failure at fine scales such as pit membranes and cell-wall mechanics, intermediate scales such as xylem network properties and at larger scales such as soil-tree hydraulic pathways are discussed. Understudied areas in plant hydraulics are also flagged where progress is urgently needed.
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Affiliation(s)
- Daniel M. Johnson
- Warnell School of Forestry and Natural ResourcesUniversity of GeorgiaAthensGeorgiaUSA
| | - Gabriel Katul
- Department of Civil and Environmental EngineeringDuke UniversityDurhamNorth CarolinaUSA
- Nicholas School of the EnvironmentDuke UniversityDurhamNorth CarolinaUSA
| | - Jean‐Christophe Domec
- Nicholas School of the EnvironmentDuke UniversityDurhamNorth CarolinaUSA
- Department of ForestryBordeaux Sciences Agro, UMR INRAE‐ISPA 1391GradignanFrance
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50
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Cory ST, Smith WK, Anderson TM. First-year Acacia seedlings are anisohydric "water-spenders" but differ in their rates of water use. AMERICAN JOURNAL OF BOTANY 2022; 109:1251-1261. [PMID: 35791878 PMCID: PMC9544296 DOI: 10.1002/ajb2.16032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
PREMISE First-year seedlings (FYS) of tree species may be a critical demographic bottleneck in semi-arid, seasonally dry ecosystems such as savannas. Given the highly variable water availability and potentially strong FYS-grass competition for water, FYS water-use strategies may play a crucial role in FYS establishment in savannas and, ultimately, in tree-grass competition and coexistence. METHODS We examined drought responses in FYS of two tree species that are dominant on opposite ends of an aridity gradient in Serengeti, Acacia (=Vachellia) tortilis and A. robusta. In a glasshouse experiment, gas exchange and whole-plant hydraulic conductance (Kplant ) were measured as soil water potential (Ψsoil ) declined. Trajectory of the Ψleaf /Ψsoil relationship during drought elucidated the degree of iso/anisohydry. RESULTS Both species were strongly anisohydric "water-spenders," allowing rapid wet-season C gain after pulses of moisture availability. Despite being equally vulnerable to declines in Kplant under severe drought, they differed in their rates of water use. Acacia tortilis, which occurs in the more arid regions, initially had greater Kmax , transpiration (E), and photosynthesis (Anet ) than A. robusta. CONCLUSIONS This work demonstrates an important mechanism of FYS establishment in savannas: Rather than investing in drought tolerance, savanna FYS maximize gas exchange during wet periods at the expense of desiccation during dry seasons. FYS establishment appears dependent on high C uptake during the pulses of water availability that characterize habitats dominated by these species. This study increases our understanding of species-scale plant ecophysiology and ecosystem-scale patterns of tree-grass coexistence.
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Affiliation(s)
- Scott T. Cory
- Department of BiologyWake Forest University1834 Wake Forest RoadWinston‐SalemNC27106USA
| | - William K. Smith
- Department of BiologyWake Forest University1834 Wake Forest RoadWinston‐SalemNC27106USA
| | - T. Michael Anderson
- Department of BiologyWake Forest University1834 Wake Forest RoadWinston‐SalemNC27106USA
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