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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Usman M, Zarebanadkouki M, Waseem M, Katsoyiannis IA, Ernst M. Mathematical modeling of arsenic(V) adsorption onto iron oxyhydroxides in an adsorption-submerged membrane hybrid system. J Hazard Mater 2020; 400:123221. [PMID: 32947682 DOI: 10.1016/j.jhazmat.2020.123221] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/10/2020] [Accepted: 06/13/2020] [Indexed: 06/11/2023]
Abstract
The adsorption of arsenic (V), As(V), on two porous iron oxyhydroxide-based adsorbents, namely, micro-sized tetravalent manganese feroxyhyte (μTMF) and granular ferric hydroxide (μGFH), applied in a submerged microfiltration membrane hybrid system has been investigated and modeled. Batch adsorption tests were carried out to determine adsorption equilibrium and kinetics parameters of As(V) in a bench-scale slurry reactor setup. A mathematical model has been developed to describe the kinetic data as well as to predict the As(V) breakthrough curves in the hybrid system based on the homogeneous surface diffusion model (HSDM) and the corresponding solute mass balance equation. The kinetic parameters describing the mass transfer resistance due to intraparticle surface diffusion (Ds) involved in the HSDM was determined. The fitted Ds values for the smaller (1-63 μm) and larger (1-250 μm) diameter particles of μGFH and μTMF were estimated to be 1.09 × 10-18 m2/s and 1.53 × 10-16 m2/s, and 2.26 × 10-18 m2/s and 1.01 × 10-16 m2/s, respectively. The estimated values of mass transfer coefficient/ kinetic parameters are then applied in the developed model to predict the As(V) concentration profiles in the effluent of the hybrid membrane system. The predicted results were compared with experimental data for As(V) removal and showed an excellent agreement. After validation at varying adsorbent doses and membrane fluxes, the developed mathematical model was used to predict the influence of different operation conditions on As(V) effluent concentration profile. The model simulations also exhibit that the hybrid system benefits from increasing the amount of adsorbent initially dosed and from decreasing the membrane flux (increasing the contact time).
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Affiliation(s)
- Muhammad Usman
- Institute for Water Resources and Water Supply, Hamburg University of Technology, Am Schwarzenberg-Campus 3, 20173, Hamburg, Germany.
| | - Mohsen Zarebanadkouki
- Chair of Soil Physics, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Muhammad Waseem
- Institute for Water Resources and Water Supply, Hamburg University of Technology, Am Schwarzenberg-Campus 3, 20173, Hamburg, Germany
| | - Ioannis A Katsoyiannis
- Laboratory of Chemical and Environmental Technology, Department of Chemistry, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Mathias Ernst
- Institute for Water Resources and Water Supply, Hamburg University of Technology, Am Schwarzenberg-Campus 3, 20173, Hamburg, Germany.
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Carminati A, Ahmed MA, Zarebanadkouki M, Cai G, Lovric G, Javaux M. Stomatal closure prevents the drop in soil water potential around roots. New Phytol 2020; 226:1541-1543. [PMID: 32077111 DOI: 10.1111/nph.16451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 11/20/2019] [Indexed: 05/14/2023]
Affiliation(s)
- Andrea Carminati
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Universitätstrasse 30, D-95447, Bayreuth, Germany
| | - Mutez Ali Ahmed
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Universitätstrasse 30, D-95447, Bayreuth, Germany
| | - Mohsen Zarebanadkouki
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Universitätstrasse 30, D-95447, Bayreuth, Germany
| | - Gaochao Cai
- Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Universitätstrasse 30, D-95447, Bayreuth, Germany
| | - Goran Lovric
- Centre d'Imagerie BioMédicale, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen, Switzerland
| | - Mathieu Javaux
- Earth and Life Institute, Université catholique de Louvain, Croix du Sud L7.05.02, B-1348, Louvain-la-Neuve, Belgium
- Agrosphere, Forschungszentrum Juelich GmbH, D-52425, Juelich, Germany
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Hayat F, Ahmed MA, Zarebanadkouki M, Javaux M, Cai G, Carminati A. Transpiration Reduction in Maize ( Zea mays L) in Response to Soil Drying. Front Plant Sci 2020; 10:1695. [PMID: 32038676 PMCID: PMC6989490 DOI: 10.3389/fpls.2019.01695] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 12/02/2019] [Indexed: 05/24/2023]
Abstract
The relationship between leaf water potential, soil water potential, and transpiration depends on soil and plant hydraulics and stomata regulation. Recent concepts of stomatal response to soil drying relate stomatal regulation to plant hydraulics, neglecting the loss of soil hydraulic conductance around the roots. Our objective was to measure the effect of soil drying on the soil-plant hydraulic conductance of maize and to test whether stomatal regulation avoids a loss of soil-plant hydraulic conductance in drying soils. We combined a root pressure chamber, in which the soil-root system is pressurized to maintain the leaf xylem at atmospheric pressure, with sap flow sensors to measure transpiration rate. The method provides accurate and high temporal resolution measurements of the relationship between transpiration rate and xylem leaf water potential. A simple soil-plant hydraulic model describing the flow of water across the soil, root, and xylem was used to simulate the relationship between leaf water potential and transpiration rate. The experiments were carried out with 5-week-old maize grown in cylinders of 9 cm diameter and 30 cm height filled with silty soil. The measurements were performed at four different soil water contents (WC). The results showed that the relationship between transpiration and leaf water potential was linear in wet soils, but as the soil dried, the xylem tension increased, and nonlinearities were observed at high transpiration rates. Nonlinearity in the relationship between transpiration and leaf water potential indicated a decrease in the soil-plant hydraulic conductance, which was explained by the loss of hydraulic conductivity around the roots. The hydraulic model well reproduced the observed leaf water potential. Parallel experiments performed with plants not being pressurized showed that plants closed stomata when the soil-plant hydraulic conductance decreased, maintaining the linearity between leaf water potential and transpiration rate. We conclude that stomata closure during soil drying is caused by the loss of soil hydraulic conductivity in a predictable way.
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Affiliation(s)
- Faisal Hayat
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
| | - Mutez Ali Ahmed
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
- Division of Soil Hydrology, University of Göttingen, Göttingen, Germany
| | | | - Mathieu Javaux
- Earth and Life Institute-Environmental Sciences, Universite Catholique de Louvain, Louvain la Neuve, Belgium
- Agrosphere (IBG-3), Forschungszentrum Juelich GmbH, Juelich, Germany
| | - Gaochao Cai
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
- Division of Soil Hydrology, University of Göttingen, Göttingen, Germany
| | - Andrea Carminati
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
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Meunier F, Zarebanadkouki M, Ahmed MA, Carminati A, Couvreur V, Javaux M. Hydraulic conductivity of soil-grown lupine and maize unbranched roots and maize root-shoot junctions. J Plant Physiol 2018; 227:31-44. [PMID: 29395124 DOI: 10.1016/j.jplph.2017.12.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 05/14/2023]
Abstract
Improving or maintaining crop productivity under conditions of long term change of soil water availability and atmosphere demand for water is one the big challenges of this century. It requires a deep understanding of crop water acquisition properties, i.e. root system architecture and root hydraulic properties among other characteristics of the soil-plant-atmosphere continuum. A root pressure probe technique was used to measure the root hydraulic conductances of seven-week old maize and lupine plants grown in sandy soil. Unbranched root segments were excised in lateral, seminal, crown and brace roots of maize, and in lateral roots of lupine. Their total hydraulic conductance was quantified under steady-state hydrostatic gradient for progressively shorter segments. Furthermore, the axial conductance of proximal root regions removed at each step of root shortening was measured as well. Analytical solutions of the water flow equations in unbranched roots developed recently and relating root total conductance profiles to axial and radial conductivities were used to retrieve the root radial hydraulic conductivity profile along each root type, and quantify its uncertainty. Interestingly, the optimized root radial conductivities and measured axial conductances displayed significant differences across root types and species. However, the measured root total conductances did not differ significantly. As compared to measurements reported in the literature, our axial and radial conductivities concentrate in the lower range of herbaceous species hydraulic properties. In a final experiment, the hydraulic conductances of root junctions to maize stem were observed to highly depend on root type. Surprisingly maize brace root junctions were an order of magnitude more conductive than the other crown and seminal roots, suggesting potential regulation mechanism for root water uptake location and a potential role of the maize brace roots for water uptake more important than reported in the literature.
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Affiliation(s)
- Félicien Meunier
- Earth and Life Institute, Environmental sciences, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | | | - Mutez A Ahmed
- Division of Soil Physics, University of Bayreuth, Bayreuth, Germany; Division of Soil Hydrology, University of Goettingen, D-37077 Göttingen, Germany; Department of Agricultural Engineering, Faculty of Agriculture, University of Khartoum, Khartoum, Sudan
| | - Andrea Carminati
- Division of Soil Physics, University of Bayreuth, Bayreuth, Germany
| | - Valentin Couvreur
- Earth and Life Institute, Agronomic sciences, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Mathieu Javaux
- Earth and Life Institute, Environmental sciences, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium; Institute of Bio- and Geosciences, IBG-3 Agrosphere, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
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Zamanian K, Zarebanadkouki M, Kuzyakov Y. Nitrogen fertilization raises CO 2 efflux from inorganic carbon: A global assessment. Glob Chang Biol 2018; 24:2810-2817. [PMID: 29575284 DOI: 10.1111/gcb.14148] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/27/2018] [Accepted: 03/11/2018] [Indexed: 06/08/2023]
Abstract
Nitrogen (N) fertilization is an indispensable agricultural practice worldwide, serving the survival of half of the global population. Nitrogen transformation (e.g., nitrification) in soil as well as plant N uptake releases protons and increases soil acidification. Neutralizing this acidity in carbonate-containing soils (7.49 × 109 ha; ca. 54% of the global land surface area) leads to a CO2 release corresponding to 0.21 kg C per kg of applied N. We here for the first time raise this problem of acidification of carbonate-containing soils and assess the global CO2 release from pedogenic and geogenic carbonates in the upper 1 m soil depth. Based on a global N-fertilization map and the distribution of soils containing CaCO3 , we calculated the CO2 amount released annually from the acidification of such soils to be 7.48 × 1012 g C/year. This level of continuous CO2 release will remain constant at least until soils are fertilized by N. Moreover, we estimated that about 273 × 1012 g CO2 -C are released annually in the same process of CaCO3 neutralization but involving liming of acid soils. These two CO2 sources correspond to 3% of global CO2 emissions by fossil fuel combustion or 30% of CO2 by land-use changes. Importantly, the duration of CO2 release after land-use changes usually lasts only 1-3 decades before a new C equilibrium is reached in soil. In contrast, the CO2 released by CaCO3 acidification cannot reach equilibrium, as long as N fertilizer is applied until it becomes completely neutralized. As the CaCO3 amounts in soils, if present, are nearly unlimited, their complete dissolution and CO2 release will take centuries or even millennia. This emphasizes the necessity of preventing soil acidification in N-fertilized soils as an effective strategy to inhibit millennia of CO2 efflux to the atmosphere. Hence, N fertilization should be strictly calculated based on plant-demand, and overfertilization should be avoided not only because N is a source of local and regional eutrophication, but also because of the continuous CO2 release by global acidification.
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Affiliation(s)
- Kazem Zamanian
- Department of Soil Science of Temperate Ecosystems, Georg-August University of Göttingen, Göttingen, Germany
| | | | - Yakov Kuzyakov
- Department of Soil Science of Temperate Ecosystems, Georg-August University of Göttingen, Göttingen, Germany
- Department of Agricultural Soil Science, Georg-August University of Göttingen, Göttingen, Germany
- Institute of Environmental Sciences, Kazan Federal University, Kazan, Russia
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Ahmed MA, Zarebanadkouki M, Meunier F, Javaux M, Kaestner A, Carminati A. Root type matters: measurement of water uptake by seminal, crown, and lateral roots in maize. J Exp Bot 2018; 69:1199-1206. [PMID: 29304205 PMCID: PMC6019006 DOI: 10.1093/jxb/erx439] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 11/11/2017] [Indexed: 05/20/2023]
Abstract
The ability of plants to take up water from the soil depends on both the root architecture and the distribution and evolution of the hydraulic conductivities among root types and along the root length. The mature maize (Zea mays L.) root system is composed of primary, seminal, and crown roots together with their respective laterals. Our understanding of root water uptake of maize is largely based on measurements of primary and seminal roots. Crown roots might have a different ability to extract water from the soil, but their hydraulic function remains unknown. The aim of this study was to measure the location of water uptake in mature maize and investigate differences between seminal, crown, and lateral roots. Neutron radiography and injections of deuterated water were used to visualize the root architecture and water transport in 5-week-old maize root systems. Water was mainly taken up by crown roots. Seminal roots and their laterals, which were the main location of water uptake in younger plants, made a minor contribution to water uptake. In contrast to younger seminal roots, crown roots were also able to take up water from their most distal segments. The greater uptake of crown roots compared with seminal roots is explained by their higher axial conductivity in the proximal parts and by the fact that they are connected to the shoot above the seminal roots, which favors the propagation of xylem tension along the crown roots. The deeper water uptake of crown roots is explained by their shorter and fewer laterals, which decreases the dissipation of water potential along the roots.
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Affiliation(s)
- Mutez Ali Ahmed
- Division of Soil Hydrology, University of Goettingen, Göttingen, Germany
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
- Correspondence:
| | | | - Félicien Meunier
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Mathieu Javaux
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Anders Kaestner
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen, Switzerland
| | - Andrea Carminati
- Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany
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Holz M, Zarebanadkouki M, Kuzyakov Y, Pausch J, Carminati A. Root hairs increase rhizosphere extension and carbon input to soil. Ann Bot 2018; 121:61-69. [PMID: 29267846 PMCID: PMC5786240 DOI: 10.1093/aob/mcx127] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 09/22/2017] [Indexed: 05/17/2023]
Abstract
BACKGROUND AND AIMS Although it is commonly accepted that root exudation enhances plant-microbial interactions in the rhizosphere, experimental data on the spatial distribution of exudates are scarce. Our hypothesis was that root hairs exude organic substances to enlarge the rhizosphere farther from the root surface. METHODS Barley (Hordeum vulgare 'Pallas' - wild type) and its root-hairless mutant (brb) were grown in rhizoboxes and labelled with 14CO2. A filter paper was placed on the soil surface to capture, image and quantify root exudates. KEY RESULTS Plants with root hairs allocated more carbon (C) to roots (wild type: 13 %; brb: 8 % of assimilated 14C) and to rhizosheaths (wild type: 1.2 %; brb: 0.2 %), while hairless plants allocated more C to shoots (wild type: 65 %; brb: 75 %). Root hairs increased the radial rhizosphere extension three-fold, from 0.5 to 1.5 mm. Total exudation on filter paper was three times greater for wild type plants compared to the hairless mutant. CONCLUSION Root hairs increase exudation and spatial rhizosphere extension, which probably enhance rhizosphere interactions and nutrient cycling in larger soil volumes. Root hairs may therefore be beneficial to plants under nutrient-limiting conditions. The greater C allocation below ground in the presence of root hairs may additionally foster C sequestration.
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Affiliation(s)
- Maire Holz
- Division of Agricultural Soil Science, University of Göttingen, Göttingen, Germany
- For correspondence.
| | | | - Yakov Kuzyakov
- Department of Soil Science of Temperate Ecosystems and Department of Agricultural Soil Science, University of Göttingen, Göttingen, Germany
- Institute of Environmental Sciences, Kazan Federal University, Kazan, Russia
| | - Johanna Pausch
- Division of Agroecology, University of Bayreuth, Bayreuth, Germany
| | - Andrea Carminati
- Division of Soil Physics, University of Bayreuth, Bayreuth, Germany
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Liu S, Zamanian K, Schleuss PM, Zarebanadkouki M, Kuzyakov Y. Degradation of Tibetan grasslands: Consequences for carbon and nutrient cycles. Agriculture, Ecosystems & Environment 2018. [PMID: 0 DOI: 10.1016/j.agee.2017.10.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
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Carminati A, Passioura JB, Zarebanadkouki M, Ahmed MA, Ryan PR, Watt M, Delhaize E. Root hairs enable high transpiration rates in drying soils. New Phytol 2017; 216:771-781. [PMID: 28758687 DOI: 10.1111/nph.14715] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 06/21/2017] [Indexed: 05/24/2023]
Abstract
Do root hairs help roots take up water from the soil? Despite the well-documented role of root hairs in phosphate uptake, their role in water extraction is controversial. We grew barley (Hordeum vulgare cv Pallas) and its root-hairless mutant brb in a root pressure chamber, whereby the transpiration rate could be varied whilst monitoring the suction in the xylem. The method provides accurate measurements of the dynamic relationship between the transpiration rate and xylem suction. The relationship between the transpiration rate and xylem suction was linear in wet soils and did not differ between genotypes. When the soil dried, the xylem suction increased rapidly and non-linearly at high transpiration rates. This response was much greater with the brb mutant, implying a reduced capacity to take up water. We conclude that root hairs facilitate the uptake of water by substantially reducing the drop in matric potential at the interface between root and soil in rapidly transpiring plants. The experiments also reinforce earlier observations that there is a marked hysteresis in the suction in the xylem when the transpiration rate is rising compared with when it is falling, and possible reasons for this behavior are discussed.
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Affiliation(s)
- Andrea Carminati
- Chair of Soil Physics, University of Bayreuth, Bauyreuth, D-95447, Germany
| | - John B Passioura
- CSIRO Agriculture and Food, GPO Box 1600, Canberra, ACT, 2601, Australia
| | | | - Mutez A Ahmed
- Chair of Soil Physics, University of Bayreuth, Bauyreuth, D-95447, Germany
- Division of Soil Hydrology, Georg-August Universität, D-37073, Göttingen, Germany
- Department of Agricultural Engineering, Faculty of Agriculture, University of Khartoum, Khartoum North, 13314, Shambat, Sudan
| | - Peter R Ryan
- CSIRO Agriculture and Food, GPO Box 1600, Canberra, ACT, 2601, Australia
| | - Michelle Watt
- Plant Sciences, Institute of Bio- and Geosciences, Jülich Forschungszentrum, Jülich, D-52425, Germany
| | - Emmanuel Delhaize
- CSIRO Agriculture and Food, GPO Box 1600, Canberra, ACT, 2601, Australia
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Zarebanadkouki M, Meunier F, Couvreur V, Cesar J, Javaux M, Carminati A. Estimation of the hydraulic conductivities of lupine roots by inverse modelling of high-resolution measurements of root water uptake. Ann Bot 2016; 118:853-864. [PMID: 27539602 PMCID: PMC5055639 DOI: 10.1093/aob/mcw154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 06/10/2016] [Indexed: 05/04/2023]
Abstract
Background and Aims Radial and axial hydraulic conductivities are key parameters for proper understanding and modelling of root water uptake. Despite their importance, there is limited experimental information on how the radial and axial hydraulic conductivities vary along roots growing in soil. Here, a new approach was introduced to estimate inversely the profile of hydraulic conductivities along the roots of transpiring plants growing in soil. Methods A three-dimensional model of root water uptake was used to reproduce the measured profile of root water uptake along roots of lupine plant grown in soil. The profile of fluxes was measured using a neutron radiography technique combined with injection of deuterated water as tracer. The aim was to estimate inversely the profiles of the radial and axial hydraulic conductivities along the roots. Key Results The profile of hydraulic conductivities along the taproot and the lateral roots of lupines was calculated using three flexible scenarios. For all scenarios, it was found that the radial hydraulic conductivity increases towards the root tips, while the axial conductivity decreases. Additionally, it was found that in soil with uniform water content: (1) lateral roots were the main location of root water uptake; (2) water uptake by laterals decreased towards the root tips due to the dissipation of water potential along the root; and (3) water uptake by the taproot was higher in the distal segments and was negligible in the proximal parts, which had a low radial conductivity. Conclusions The proposed approach allows the estimation of the root hydraulic properties of plants growing in soil. This information can be used in an advanced model of water uptake to predict the water uptake of different root types or different root architectures under varying soil conditions.
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Affiliation(s)
- Mohsen Zarebanadkouki
- Georg August University of Goettingen, Division of Soil Hydrology, Buesgenweg 2, D-37077 Goettingen, Germany
- *For correspondence. E-mail
| | - Félicien Meunier
- Université catholique de Louvain, Earth and Life Institute-Environnemental Sciences, Louvain-la Neuve, Belgium
| | - Valentin Couvreur
- Université catholique de Louvain, Earth and Life Institute-Agronomy, Louvain-la Neuve, Belgium
| | - Jimenez Cesar
- Georg August University of Goettingen, Division of Soil Hydrology, Buesgenweg 2, D-37077 Goettingen, Germany
| | - Mathieu Javaux
- Université catholique de Louvain, Earth and Life Institute-Environnemental Sciences, Louvain-la Neuve, Belgium
- University of California Davis, Department of Land, Air and Water Resources, Davis, CA, USA
- Forschungszentrum Juelich GmbH, IBG-3: Agrosphere, Juelich, Germany
| | - Andrea Carminati
- Georg August University of Goettingen, Division of Soil Hydrology, Buesgenweg 2, D-37077 Goettingen, Germany
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Carminati A, Zarebanadkouki M, Kroener E, Ahmed MA, Holz M. Biophysical rhizosphere processes affecting root water uptake. Ann Bot 2016; 118:561-571. [PMID: 27345032 PMCID: PMC5055629 DOI: 10.1093/aob/mcw113] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/29/2016] [Accepted: 04/08/2016] [Indexed: 05/09/2023]
Abstract
Background Recent advances in imaging techniques now make it possible to visualize the biogeochemical and physical environment around the roots, the rhizosphere. Detailed images of pore space geometry and water content dynamics around roots have demonstrated the heterogeneity of the rhizosphere compared with the soil far from the roots. These findings have inspired new models of root water uptake which aim to describe such small-scale heterogeneity. However, the question remains of how far these image-based findings have really advanced our understanding of how roots extract water from soils. Scope The rhizosphere processes affecting root water uptake are reviewed. Special attention is dedicated to the role of mucilage exuded by roots. Mucilage increases the soil moisture at negative water potentials and it keeps the rhizosphere wet when plants take up water, possibly maintaining the hydraulic connection between roots and soil. However, mucilage becomes viscous and hydrophobic upon severe drying and it limits the water fluxes across the rhizosphere during the rewetting phase. The role of mucilage in maintaining the hydraulic contact between the root surface and the surrounding soil, thereby softening the drops in water potential around the roots in dry soils, remains to be demonstrated. Conclusion Despite detailed images of water content, water fluxes and soil structure in the rhizosphere, a general understanding of how the rhizosphere affects root water uptake is still lacking. The missing elements of the puzzle are the gradient in water potential around roots. Measurements of the xylem water potential at varying soil water potentials and transpiration rates supported by numerical models of root water uptake would allow the estimation of the water potential across the rhizosphere. Such measurements are crucial to comprehend how water enters the roots.
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Affiliation(s)
- A. Carminati
- Division of Soil Hydrology, Georg-August University, Göttingen, Germany
| | - M. Zarebanadkouki
- Division of Soil Hydrology, Georg-August University, Göttingen, Germany
| | - E. Kroener
- Division of Soil Hydrology, Georg-August University, Göttingen, Germany
| | - M. A. Ahmed
- Division of Soil Hydrology, Georg-August University, Göttingen, Germany
- Department of Agricultural Engineering, Faculty of Agriculture, University of Khartoum, Khartoum North, 13314 Shambat, Sudan
| | - M. Holz
- Division of Soil Hydrology, Georg-August University, Göttingen, Germany
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Ahmed MA, Kroener E, Holz M, Zarebanadkouki M, Carminati A. Mucilage exudation facilitates root water uptake in dry soils. Funct Plant Biol 2014; 41:1129-1137. [PMID: 32481063 DOI: 10.1071/fp13330] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 03/25/2014] [Indexed: 05/14/2023]
Abstract
As plant roots take up water and the soil dries, water depletion is expected to occur in the rhizosphere. However, recent experiments showed that the rhizosphere was wetter than the bulk soil during root water uptake. We hypothesise that the increased water content in the rhizosphere was caused by mucilage exuded by roots. It is probably that the higher water content in the rhizosphere results in higher hydraulic conductivity of the root-soil interface. In this case, mucilage exudation would favour the uptake of water in dry soils. To test this hypothesis, we covered a suction cup, referred to as an artificial root, with mucilage. We placed it in soil with a water content of 0.03cm3cm-3, and used the root pressure probe technique to measure the hydraulic conductivity of the root-soil continuum. The results were compared with measurements with roots not covered with mucilage. The root pressure relaxation curves were fitted with a model of root water uptake including rhizosphere dynamics. The results demonstrated that when mucilage is added to the root surface, it keeps the soil near the roots wet and hydraulically well conductive, facilitating the water flow from dry soils towards the root surface. Mucilage exudation seems to be an optimal plant trait that favours the capture of water when water is scarce.
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Affiliation(s)
- Mutez A Ahmed
- Division of Soil Hydrology, Georg-August University of Göttingen, Göttingen 37077, Germany
| | - Eva Kroener
- Division of Soil Hydrology, Georg-August University of Göttingen, Göttingen 37077, Germany
| | - Maire Holz
- Division of Soil Hydrology, Georg-August University of Göttingen, Göttingen 37077, Germany
| | - Mohsen Zarebanadkouki
- Division of Soil Hydrology, Georg-August University of Göttingen, Göttingen 37077, Germany
| | - Andrea Carminati
- Division of Soil Hydrology, Georg-August University of Göttingen, Göttingen 37077, Germany
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Zarebanadkouki M, Kroener E, Kaestner A, Carminati A. Visualization of root water uptake: quantification of deuterated water transport in roots using neutron radiography and numerical modeling. Plant Physiol 2014; 166:487-99. [PMID: 25189533 PMCID: PMC4213081 DOI: 10.1104/pp.114.243212] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 09/01/2014] [Indexed: 05/04/2023]
Abstract
Our understanding of soil and plant water relations is limited by the lack of experimental methods to measure water fluxes in soil and plants. Here, we describe a new method to noninvasively quantify water fluxes in roots. To this end, neutron radiography was used to trace the transport of deuterated water (D2O) into roots. The results showed that (1) the radial transport of D2O from soil to the roots depended similarly on diffusive and convective transport and (2) the axial transport of D2O along the root xylem was largely dominated by convection. To quantify the convective fluxes from the radiographs, we introduced a convection-diffusion model to simulate the D2O transport in roots. The model takes into account different pathways of water across the root tissue, the endodermis as a layer with distinct transport properties, and the axial transport of D2O in the xylem. The diffusion coefficients of the root tissues were inversely estimated by simulating the experiments at night under the assumption that the convective fluxes were negligible. Inverse modeling of the experiment at day gave the profile of water fluxes into the roots. For a 24-d-old lupine (Lupinus albus) grown in a soil with uniform water content, root water uptake was higher in the proximal parts of lateral roots and decreased toward the distal parts. The method allows the quantification of the root properties and the regions of root water uptake along the root systems.
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Affiliation(s)
- Mohsen Zarebanadkouki
- Georg August University of Goettingen, Division of Soil Hydrology, 37077 Goettingen, Germany (M.Z., E.K., A.C.); andPaul Scherrer Institute, 5232 Villigen PSI, Switzerland (A.K.)
| | - Eva Kroener
- Georg August University of Goettingen, Division of Soil Hydrology, 37077 Goettingen, Germany (M.Z., E.K., A.C.); andPaul Scherrer Institute, 5232 Villigen PSI, Switzerland (A.K.)
| | - Anders Kaestner
- Georg August University of Goettingen, Division of Soil Hydrology, 37077 Goettingen, Germany (M.Z., E.K., A.C.); andPaul Scherrer Institute, 5232 Villigen PSI, Switzerland (A.K.)
| | - Andrea Carminati
- Georg August University of Goettingen, Division of Soil Hydrology, 37077 Goettingen, Germany (M.Z., E.K., A.C.); andPaul Scherrer Institute, 5232 Villigen PSI, Switzerland (A.K.)
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Zarebanadkouki M, Kim YX, Carminati A. Where do roots take up water? Neutron radiography of water flow into the roots of transpiring plants growing in soil. New Phytol 2013; 199:1034-1044. [PMID: 23692148 DOI: 10.1111/nph.12330] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/11/2013] [Indexed: 05/04/2023]
Abstract
Where and how fast does water flow from soil into roots? The answer to this question requires direct and in situ measurement of local flow of water into roots of transpiring plants growing in soil. We used neutron radiography to trace the transport of deuterated water (D₂O) in lupin (Lupinus albus) roots. Lupins were grown in aluminum containers (30 × 25 × 1 cm) filled with sandy soil. D₂O was injected in different soil regions and its transport in soil and roots was monitored by neutron radiography. The transport of water into roots was then quantified using a convection-diffusion model of D₂O transport into roots. The results showed that water uptake was not uniform along roots. Water uptake was higher in the upper soil layers than in the lower ones. Along an individual root, the radial flux was higher in the proximal segments than in the distal segments. In lupins, most of the water uptake occurred in lateral roots. The function of the taproot was to collect water from laterals and transport it to the shoot. This function is ensured by a low radial conductivity and a high axial conductivity. Lupin root architecture seems well designed to take up water from deep soil layers.
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Affiliation(s)
| | - Yangmin X Kim
- Soil Hydrology, Georg August University of Göttingen, 37077, Göttingen, Germany
| | - Andrea Carminati
- Soil Hydrology, Georg August University of Göttingen, 37077, Göttingen, Germany
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