24 results on '"Benard, Pascal"'
Search Results
2. Root and rhizosphere traits for enhanced water and nutrients uptake efficiency in dynamic environments.
- Author
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Holz, Maire, Zarebanadkouki, Mohsen, Benard, Pascal, Hoffmann, Mathias, and Dubbert, Maren
- Subjects
EXUDATION (Botany) ,PLANT breeding ,EXTREME weather ,NUTRIENT uptake ,STABLE isotopes - Abstract
Modern agriculture's goal of improving crop resource acquisition efficiency relies on the intricate relationship between the root system and the soil. Root and rhizosphere traits play a critical role in the efficient use of nutrients and water, especially under dynamic environments. This review emphasizes a holistic perspective, challenging the conventional separation of nutrient and water uptake processes and the necessity for an integrated approach. Anticipating climate change-induced increase in the likelihood of extreme weather events that result in fluctuations in soil moisture and nutrient availability, the study explores the adaptive potential of root and rhizosphere traits to mitigate stress. We emphasize the significance of root and rhizosphere characteristics that enable crops to rapidly respond to varying resource availabilities (i.e. the presence of water and mobile nutrients in the root zone) and their accessibility (i.e. the possibility to transport resources to the root surface). These traits encompass for example root hairs, mucilage and extracellular polymeric substance (EPS) exudation, rhizosheath formation and the expression of nutrient and water transporters. Moreover, we recognize the challenge of balancing carbon investments, especially under stress, where optimized traits must consider carbon-efficient strategies. To advance our understanding, the review calls for well-designed field experiments, recognizing the limitations of controlled environments. Non-destructive methods such as mini rhizotron assessments and in-situ stable isotope techniques, in combination with destructive approaches such as root exudation analysis, are proposed for assessing root and rhizosphere traits. The integration of modeling, experimentation, and plant breeding is essential for developing resilient crop genotypes capable of adapting to evolving resource limitation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Rhizosphere hydrophobicity limits root water uptake after drying and subsequent rewetting
- Author
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Zarebanadkouki, Mohsen, Ahmed, Mutez, Hedwig, Clemens, Benard, Pascal, Kostka, Stanley J., Kastner, Anders, and Carminati, Andrea
- Published
- 2018
4. Variations in pore size and contact angle distributions control rhizosphere rewetting
- Author
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Benard, Pascal, Bachmann, Jörg, Zarebanadkouki, Mohsen, Schlüter, Steffen, Blaser, Sebastian R.G.A., Kaestner, Per Anders, and Carminati, Andrea
- Subjects
Mucilage ,Neutron imaging ,Rhizosphere ,Soil wettability ,Pore network model - Abstract
Rhizosphere wettability decreases upon severe drying leading to periods of prolonged low water content around roots after precipitation or irrigation. These observations were explained by the temporal hydrophobic character of mucilage, while structural alterations of the pore space caused by mucilage, such as pore clogging, remained mostly unexplored. In this study, time-series neutron radiography and a pore network model were used to assess the impact of pore geometry and wettability on water flow following the addition of mucilage in a sand substrate. To do so, we monitored the capillary rise of ethanol and water separately for mucilage contents, ranging from 0.0 to 2.0 mg g−1. A pore network model was developed to analyze the impact of alterations in pore geometry and wettability. Results are compared with analytical solutions of the Lucas-Washburn equation. Rewetting dynamics were explained by a combination of a decrease in effective pore throat size and a global decrease in wettability. The local distribution of wettability, however, appeared of minor importance as dynamics of water imbibition could be matched by a uniform effective contact angle. For 0.1 mg g−1 mucilage content increased wettability was predicted for both approaches: the analytical solution and the pore network model fit. At larger contents, a decrease in wettability occurred which was accompanied by a decrease in derived effective pore and pore throat size. On a minute scale, rewetting appeared to steadily progress at all mucilage contents with accelerated rewetting observed at 0.6 mg g−1 likely related to an increased wetting front length. This study highlights the importance of mucilage on pore geometry in combination with wettability modifications in the rhizosphere. Aside from rhizosphere rewetting, the presented approach provides an opportunity to investigate further wettability-related processes in other soil environments on various spatial scales., Geoderma, 437, ISSN:0016-7061, ISSN:1872-6259
- Published
- 2023
5. Drying of mucilage causes water repellency in the rhizosphere of maize: measurements and modelling
- Author
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Ahmed, Mutez Ali, Kroener, Eva, Benard, Pascal, Zarebanadkouki, Mohsen, Kaestner, Anders, and Carminati, Andrea
- Published
- 2016
6. Water percolation through the root-soil interface
- Author
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Benard, Pascal, Kroener, Eva, Vontobel, Peter, Kaestner, Anders, and Carminati, Andrea
- Published
- 2016
- Full Text
- View/download PDF
7. Microplastic induces soil water repellency and limits capillary flow
- Author
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Cramer, Andreas, Benard, Pascal, Zarebanadkouki, Mohsen, Kaestner, Per Anders, and Carminati, Andrea
- Abstract
Soils are considered the largest sink of microplastic (MP) in terrestrial ecosystems. However, little is known about the implications of MP on soil physical properties. We hypothesize that low wettability of MP induces soil water repellency, depending on MP content and size of MP and soil particles. We quantified wettability of mixtures of MP and sand. The sessile drop method (SDM) was applied to measure static contact angle (CA) of MP and glass beads at contents ranging from 0 to 100% (w/w). The results are extrapolated to varying combinations of MP and soil particle sizes based on specific surface area. Capillary rise was imaged with neutron radiography quantifying the effect of MP on dynamic CA, water imbibition, and water saturation distribution in sand. At 5% (w/w) MP content, static CA exhibited a steep increase to 80.2 degrees for MP 20-75 mu m and 59.7 degrees for MP 75-125 mu m. Dynamic CAs were approximately 40% lower than static CAs. Capillary rise experiments showed that MP 20-75 mu m reduced water imbibition into sand columns (700-1,200 mu m), with average dynamic CA of 40.3 degrees at 0.35% (w/w) MP content and 51.8 degrees at 1.05%. Decreased water saturation and increased tortuosity of flow paths were observed during imbibition peaking at 3.5% (w/w) local MP content. We conclude, in regions with high MP content. water infiltration and thus MP transport are hindered. Local low wettability induced by MP is expected to limit soil wettability and impede capillary rise., Vadose Zone Journal, 22 (1), ISSN:1539-1663
- Published
- 2023
- Full Text
- View/download PDF
8. Ferrihydrite coating reduces microplastic induced soil water repellency.
- Author
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Cramer, Andreas, Schmidtmann, Johanna, Benard, Pascal, Kaestner, Anders, Engelhardt, Matthias, Peiffer, Stefan, and Carminati, Andrea
- Abstract
Addition of microplastics (MP) to soil has the potential to increase soil water repellency. However, coating of MP with soil abundant substances e.g., iron compounds, can reduce this effect. Here, we tested if pre-coating or in situ coating of MP with ferrihydrite (Fh) reduces soil water repellency. We applied hotspots of pristine and coated MP (20–75 μm, PS and PET) to sand and imaged capillary rise via neutron radiography. Capillary rise experiments in wetting–drying cycles were conducted using water and Fh suspension. Pristine MP hotspots were not wettable. Capillary rise of water into coated MP hotspots differed in wettability depending on polymer type. While coated PS was still non-wettable, water imbibed into the coated PET hotspot. Capillary rise of Fh suspensions in wetting and drying cycles also showed varying results depending on polymer type. MP hotspots were still non-wettable and local water content increased only marginally. Our results indicate that Fh coating of MP changes MP surface wettability depending on polymer type and therefore counteracts the hydrophobic properties of pristine MP. However, MP coating is likely to be slowed down by the initial hydrophobicity of pristine MP. Dynamics of MP coating and increasing wettability are key factors for biotic and abiotic degradation processes. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
9. In situ measurement of 3D contact angle in sand based on X-ray computed tomography
- Author
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Schlüter, Steffen, Blaser, Sebastian R.G.A., Benard, Pascal, and Carminati, Andrea
- Abstract
Soil water repellency is traditionally expressed as contact angle (CA) and measured destructively on exposed surfaces or derived from flow behavior or measured forces. These approaches cannot map local heterogeneities in CA, which typically exist in intact soil. Here, we explore the potential and limitations of in situ measurements of three-dimensional CAs with simplified benchmark tests and in intact sand. The method is based on a protocol for the freely available OpenFOAM software and applied to segmented X-ray computed tomography (X-ray CT) data. This study scrutinizes its suitability under typical vadose zone conditions, as it was originally developed for rock studies in petroleum engineering. The assets of the method are that it allows for accurate measurement of locally varying, equilibrium contact angles and that they can be linked to pore scale features that cause them. This is demonstrated with rehydrated mucilage structures in sand and the associated change in local CAs, where they touch sand grains. In general, the image acquisition time of polychromatic X-ray CT (minutes) precludes the assessments of dynamic CAs that may equilibrate within seconds. Another limitation is that acute CAs are overestimated due to the voxel discretization of interfaces and contact lines in combination with image smoothing. The divergence arises around 60 degrees and is most severe in the limit of vanishing water repellency. In summary, the method enables the mapping of local heterogeneities of equilibrium CAs, though the absolute values should be critically assessed., Vadose Zone Journal, 21 (3), ISSN:1539-1663
- Published
- 2022
10. Biogels in Soils: Plant Mucilage as a Biofilm Matrix That Shapes the Rhizosphere Microbial Habitat
- Author
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Nazari, Meisam, Bickel, Samuel, Benard, Pascal, Mason-Jones, Kyle, Carminati, Andrea, Dippold, Michaela A., and Terrestrial Ecology (TE)
- Subjects
microorganism ,international ,Hypothesis and Theory ,Plant culture ,Plant Science ,EPS ,rhizosphere ,root ,Plan_S-Compliant-OA ,biofilm ,mucilage ,SB1-1110 - Abstract
Mucilage is a gelatinous high-molecular-weight substance produced by almost all plants, serving numerous functions for plant and soil. To date, research has mainly focused on hydraulic and physical functions of mucilage in the rhizosphere. Studies on the relevance of mucilage as a microbial habitat are scarce. Extracellular polymeric substances (EPS) are similarly gelatinous high-molecular-weight substances produced by microorganisms. EPS support the establishment of microbial assemblages in soils, mainly through providing a moist environment, a protective barrier, and serving as carbon and nutrient sources. We propose that mucilage shares physical and chemical properties with EPS, functioning similarly as a biofilm matrix covering a large extent of the rhizosphere. Our analyses found no evidence of consistent differences in viscosity and surface tension between EPS and mucilage, these being important physical properties. With regard to chemical composition, polysaccharide, protein, neutral monosaccharide, and uronic acid composition also showed no consistent differences between these biogels. Our analyses and literature review suggest that all major functions known for EPS and required for biofilm formation are also provided by mucilage, offering a protected habitat optimized for nutrient mobilization. Mucilage enables high rhizomicrobial abundance and activity by functioning as carbon and nutrient source. We suggest that the role of mucilage as a biofilm matrix has been underestimated, and should be considered in conceptual models of the rhizosphere., Frontiers in Plant Science, 12, ISSN:1664-462X
- Published
- 2022
- Full Text
- View/download PDF
11. How Heterogeneous Pore Scale Distributions of Wettability Affect Infiltration into Porous Media.
- Author
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Bentz, Jonas, Patel, Ravi A., Benard, Pascal, Lieu, Alice, Haupenthal, Adrian, and Kroener, Eva
- Subjects
TWO-phase flow ,SOIL particles ,CONTACT angle ,SANDY soils ,RHIZOSPHERE ,MUCILAGE ,POROUS materials ,WETTING - Abstract
Wettability is an important parameter that significantly determines hydrology in porous media, and it especially controls the flow of water across the rhizosphere—the soil-plant interface. However, the influence of spatially heterogeneous distributions on the soil particles surfaces is scarcely known. Therefore, this study investigates the influence of spatially heterogeneous wettability distributions on infiltration into porous media. For this purpose, we utilize a two-phase flow model based on Lattice-Boltzmann to numerically simulate the infiltration in porous media with a simplified geometry and for various selected heterogeneous wettability coatings. Additionally, we simulated the rewetting of the dry rhizosphere of a sandy soil where dry hydrophobic mucilage depositions on the particle surface are represented via a locally increased contact angle. In particular, we can show that hydraulic dynamics and water repellency are determined by the specific location of wettability patterns within the pore space. When present at certain locations, tiny hydrophobic depositions can cause water repellency in an otherwise well-wettable soil. In this case, averaged, effective contact angle parameterizations such as the Cassie equation are unsuitable. At critical conditions, when the rhizosphere limits root water uptake, consideration of the specific microscale locations of exudate depositions may improve models of root water uptake. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
12. Microhydrological Niches in Soils: How Mucilage and EPS Alter the Biophysical Properties of the Rhizosphere and Other Biological Hotspots
- Author
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Benard, Pascal, Zarebanadkouki, Mohsen, Brax, Mathilde, Kaltenbach, Robin, Jerjen, Iwan, Marone, Federica, Couradeau, Estelle, Felde, Vincent J. M. N. L., Kaestner, Anders, and Carminati, Andrea
- Subjects
lcsh:GE1-350 ,lcsh:Geology ,EPS, extracellular polymeric substances ,PSI, Paul Scherrer Institute ,SRXTM, synchrotronbased X-ray tomographic microscopy ,lcsh:QE1-996.5 ,lcsh:Environmental sciences - Abstract
Plant roots and bacteria are capable of buffering erratic fluctuations of water content in their local soil environment by releasing a diverse, highly polymeric blend of substances (e.g. extracellular polymeric substances [EPS] and mucilage). Although this concept is well accepted, the physical mechanisms by which EPS and mucilage interact with the soil matrix and determine the soil water dynamics remain unclear. High-resolution X-ray computed tomography revealed that upon drying in porous media, mucilage (from maize [Zea mays L.] roots) and EPS (from intact biocrusts) form filaments and two-dimensional interconnected structures spanning across multiple pores. Unlike water, these mucilage and EPS structures connecting soil particles did not break up upon drying, which is explained by the high viscosity and low surface tension of EPS and mucilage. Measurements of water retention and evaporation with soils mixed with seed mucilage show how these one- and two-dimensional pore-scale structures affect macroscopic hydraulic properties (i.e., they enhance water retention, preserve the continuity of the liquid phase in drying soils, and decrease vapor diffusivity and local drying rates). In conclusion, we propose that the release of viscous polymeric substances and the consequent creation of a network bridging the soil pore space represent a universal strategy of plants and bacteria to engineer their own soil microhydrological niches where stable conditions for life are preserved. ISSN:1539-1663
- Published
- 2019
13. Microhydrological niches in soils : how mucilage and EPS alter soil hydraulic properties and water dynamics
- Author
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Benard, Pascal
- Subjects
Soil Biophysics ,Root-Soil Interface ,Mucilage ,Rhizosphere ,Hydrophobicity ,Liquid Conncetivity ,Pore-network Model - Abstract
The soil offers numerous challenges to life residing in its porous environment. One of these challenges are fluctuations in soil water content which are accompanied by shifts in soil hydraulic properties. In order to avoid undesirable alterations and optimise growth conditions, plants and bacteria engineer their local environment by release of mucilage and EPS (extracellular polymeric substances). So far, modifications of soil properties were mainly attributed to the intrinsic properties of these highly polymeric blends. In this work, we focused on deriving a mechanistic understanding of how mucilage and EPS interact with the soil pore space and how these interactions impact soil hydraulic properties and water dynamics in the rhizosphere and other biological hotspots in soils. Mucilage and EPS are capable of absorbing large volumes of water, increase the viscosity of the soil solution and decrease its surface tension. Upon drying, mucilage turns water repellent. Here, we proposed a conceptual model linking the intrinsic physical properties of mucilage to their impact on soil hydrology. The increase in viscosity is related to the high content of polymers which can form an interconnected network. As the soil dries, mucilage and EPS become increasingly concentrated, the viscosity of the soil solution locally increases and its surface tension decreases. When a critical viscosity is reached and parts of the polymer network are adsorbed to drying surfaces, the retreat of the liquid front is delayed and its break-up due to capillary forces is prevented. This concept is confirmed by microscopy imaging and high resolution X-ray CT, which revealed that mucilage and EPS form filaments and two-dimensional structures in this process. Upon drying in porous media, mucilage at low concentrations (mass of dry gel per mass of dry soil) resulted in the formation of filaments. With increase in initial mucilage concentration, two-dimensional surfaces formed when the water content was relatively high and the liquid phase connected. Complementary measurements of soil hydraulic properties of mucilage amended soils showed how the formation of these continuous two-dimensional structures impacts soil physical properties, such as soil hydraulic conductivity, soil water retention and vapour diffusion. The maintained liquid connectivity in drying soils, which is caused by the high viscosity, low surface tension and interaction of the polymer network with the soil porous matrix, explains why the hydraulic conductivity of a mucilage amended sandy loam was higher at low soil water content when compared to its control, as shown in evaporation experiments. Additionally, the delayed retreat of the liquid phase at a critical mucilage concentration creates an additional matric (capillary) potential and enhances soil water retention. To separate and quantify this matric (capillary) effect from the intrinsic property of the polymer network to absorb water remains an open task. Furthermore, upon severe soil drying, the network of two-dimensional structures reduces vapour diffusion and thus delays soil drying. This effect was illustrated using time series neutron radiography to visualise the drying of mucilage amended sandy loam and a water saturated control. Besides affecting soil hydraulic properties and evaporation rates during soil drying, mucilage impacts the rewetting kinetics. Mucilage amended soils showed water repellency. Precisely, a sharp decrease in wettability was observed near mucilage contents at which one-dimensional structures were replaced by two-dimensional continuous surfaces. Simulation of water drop infiltration experiments in mucilage amended soils showed that the creation of continuous clusters of non-wettable pores induced a substantial decrease in soil wettability, indicated by a transition of water drop penetration time from milliseconds to minutes. Although most experiments presented here were based on simplified systems, such as mucilage amended porous media, we propose that the release of highly polymeric blends into the soil pore space represents a universal strategy of soil organisms. Plants and bacteria engineer the physical properties of their local environment in very similar and astoundingly effective ways. The mechanisms discovered in this thesis lead to hydraulic decoupling of biological hotspots (e.g. the rhizosphere or biocrust) and buffer the erratic fluctuations experienced by soil organisms in these microhydrological niches.
- Published
- 2019
- Full Text
- View/download PDF
14. Impact of Pore-Scale Wettability on Rhizosphere Rewetting
- Author
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Benard, Pascal, Zarebanadkouki, Mohsen, and Carminati, Andrea
- Subjects
General Environmental Science - Published
- 2018
- Full Text
- View/download PDF
15. Bypass and hyperbole in soil science: A perspective from the next generation of soil scientists.
- Author
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Portell, Xavier, Sauzet, Ophélie, Balseiro‐Romero, María, Benard, Pascal, Cardinael, Rémi, Couradeau, Estelle, Danra, Dieudonné D., Evans, Daniel L., Fry, Ellen L., Hammer, Edith C., Mamba, Danielle, Merino‐Martín, Luis, Mueller, Carsten W., Paradelo, Marcos, Rees, Frédéric, Rossi, Lorenzo, Schmidt, Hannes, Schnee, Laura S., Védère, Charlotte, and Vidal, Alix
- Subjects
SOIL science ,SOIL scientists ,HYPERBOLE - Abstract
Here, we present our collective musings on soil research challenges and opportunities and, in particular, the points raised by Philippe Baveye (Baveye, 2020a, 2020b) and Johan Bouma (Bouma, 2020) on I bypass i and I hyperbole i in soil science. Furthermore, developing a healthy and constructive post-publication peer-review system, where bypasses and hyperbolic approaches can be identified and discussed, would ultimately boost publication quality and contribute to a more open discourse in soil science. [Extracted from the article]
- Published
- 2021
- Full Text
- View/download PDF
16. Physics and hydraulics of the rhizosphere network.
- Author
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Benard, Pascal, Zarebanadkouki, Mohsen, and Carminati, Andrea
- Subjects
- *
HYDRAULICS , *RHIZOSPHERE , *MUCILAGE , *WATER , *SOIL solutions - Abstract
Take home messageMucilage secreted by roots and EPS produced by microorganisms alter the physical properties of the soil solution and impact the water dynamics in the rhizosphere. The high viscosity of mucilage and EPS is responsible for the formation of thin filaments and interconnected thin lamellae that span throughout the soil matrix maintaining the continuity of the liquid phase across the pore space even during severe drying. The impact of these mechanisms on plant and microorganisms needs to be explored. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
17. Mucilage Facilitates Nutrient Diffusion in the Drying Rhizosphere.
- Author
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Zarebanadkouki, Mohsen, Fink, Theresa, Benard, Pascal, and Banfield, Callum C.
- Abstract
Core Ideas: Our aim was to test whether mucilage promotes diffusion of nutrients in dry soil.Mucilage favors transport of nutrients in drying soil and their uptake by plant.Mucilage increases the soil moisture in the rhizosphere as soil dries.Mucilage maintains the connectivity of liquid phase in the rhizosphere as soil dries. Despite detailed investigations of its distinct biochemical properties and their effects on the availability of nutrients for plants, the biophysical aspects of the rhizosphere, particularly the effect of mucilage on the transport of water and nutrients, are poorly understood. The aim of this study was to investigate the effect of mucilage on the diffusion of nutrients and consequently their transport through the rhizosphere into the plant roots. Phosphor imaging technique determined the temporospatial distribution of 137Cs in a model rhizosphere (a sandy soil mixed with chia seed (Salvia hispanica L) mucilage. The observed profiles of activities were used to estimate the diffusion coefficient of K in soils. A diffusion–convection equation was numerically solved to predict the transport of K and its uptake by a single plant root in drying soil. The results suggest that mucilage (i) keeps the rhizosphere wet and (ii) maintains the connectivity of the liquid phase in drying soil. In these ways, mucilage moderates the drop in diffusive transport. The modeling results showed that the presence of mucilage in the rhizosphere (i) prevents depletion of nutrients in soils with a low nutrient concentration in the soil solution and (ii) delays the risk of nutrient and/or salt accumulation in the vicinity of the root in soils with a high concentration nutrient and/or salt the soil solution. In conclusion, mucilage appears to mitigate the risk of nutrient deficiency and salinity stress as it enhances the diffusive transport in drying soil. In this way, mucilage may favor the transport of nutrients within the rhizosphere and their uptake by plant roots in drying soil. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
18. How mucilage and EPS shape the spatial configuration of the liquid phase in the rhizosphere and other soil hotspots.
- Author
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Carminati, Andrea, Benard, Pascal, Schepers, Judith, and Zarebanadkouki, Mohsen
- Subjects
- *
MUCILAGE , *GEOLOGIC hot spots , *SOIL moisture , *MICROBIAL exopolysaccharides , *SOIL dynamics , *POROUS materials - Abstract
Plant roots and bacteria are capable of altering their local soil environment by releasing a diverse, highly polymeric blend of substances (e.g. extracellular polymeric substances EPS and mucilage). Despite the importance of EPS and mucilage for plants and microorganisms is well accepted, the physical mechanisms by which EPS and mucilage interact with the soil matrix and determine the soil water dynamics remain unclear. High-resolution X-ray CT revealed that upon drying in porous media mucilage and EPS form one-dimensional filaments and two-dimensional interconnected structures spanning across multiple pores. Unlike water, these mucilage and EPS structures connecting soil particles did not break up upon drying, which is explained by the high viscosity and low surface tension of EPS and mucilage. During drying the polymers are progressively stretched and their viscosity exponentially increases until a critical point when the polymers can no longer follow the receding air-liquid interface. At this critical point the polymers start to behave as a solid matrix that enhances the soil water retention and connectivity of the liquid phase. A model is introduced to predict the formation these one- and two-dimensional polymer structures in drying porous media. Viscosity of the soil solution, drying rate and specific soil surface are the key parameters determining the transition from one- to two-dimensional structures. The model also explains the apparent hysteresis in the relation between water content and water potential in soils embedded with root mucilage. We propose that the release of viscous polymeric substances and the consequent creation of a network bridging the soil pore space represent a universal strategy of plants and bacteria to engineer their own soil micro-hydrological niches where stable conditions for life are preserved. [ABSTRACT FROM AUTHOR]
- Published
- 2019
19. Micro-hydrological niches in soils: how mucilage and EPS alter the biophysical properties of the rhizosphere and other biological hot spots.
- Author
-
Benard, Pascal, Zarebandkouki, Mohsen, Brax, Mathilde, Kaltenbach, Robin, Jerjen, Iwan, Marone, Federica, Couradeau, Estelle, Felde, Vincent, Kaestner, Anders, and Carminati, Andrea
- Subjects
- *
MUCILAGE , *GEOLOGIC hot spots , *SOIL moisture , *MICROBIAL exopolysaccharides , *SOIL dynamics , *POROUS materials - Abstract
Plant roots and bacteria are capable of buffering erratic fluctuations of water content in their local soil environment by releasing a diverse, highly polymeric blend of substances (e.g. extracellular polymeric substances EPS and mucilage). Despite this concept is well accepted, the physical mechanisms by which EPS and mucilage interact with the soil matrix and determine the soil water dynamics remain unclear. High-resolution X-ray CT revealed that upon drying in porous media mucilage (from maize roots) and EPS (from intact biocrusts) form filaments and two-dimensional interconnected structures spanning across multiple pores. Unlike water, these mucilage and EPS structures connecting soil particles did not break up upon drying, which is explained by the high viscosity and low surface tension of EPS and mucilage. Measurements of water retention and evaporation with soils mixed with seed mucilage show how these one- and two-dimensional pore-scale structures impact macroscopic hydraulic properties: i.e. they enhance water retention, preserve the continuity of the liquid phase in drying soils and decreases vapor diffusivity and local drying rates. In conclusion, we propose that the release of viscous polymeric substances and the consequent creation of a network bridging the soil pore space represent a universal strategy of plants and bacteria to engineer their own soil micro-hydrological niches where stable conditions for life are preserved. [ABSTRACT FROM AUTHOR]
- Published
- 2019
20. How mucilage may affect nutrient diffusion in the drying rhizosphere.
- Author
-
Zarebanadkouki, Mohsen, Fink, Theresa, Benard, Pascal, and Banfield, Callum
- Published
- 2019
21. Mucilage Facilitates Nutrient Diffusion in the Drying Rhizosphere
- Author
-
Zarebanadkouki, Mohsen, Fink, Theresa, Benard, Pascal, and Banfield, Callum C.
- Subjects
2. Zero hunger ,15. Life on land
22. Bypass and hyperbole in soil science: A perspective from the next generation of soil scientists
- Author
-
Portell, Xavier, Sauzet, Ophélie, Balseiro‐Romero, María, Benard, Pascal, Cardinael, Rémi, Couradeau, Estelle, Danra, Dieudonné D., Evans, Daniel L., Fry, Ellen L., Hammer, Edith C., Mamba, Danielle, Merino‐Martín, Luis, Mueller, Carsten W., Paradelo, Marcos, Rees, Frédéric, Rossi, Lorenzo, Schmidt, Hannes, Schnee, Laura S., Védère, Charlotte, and Vidal, Alix
- Subjects
13. Climate action - Abstract
European Journal of Soil Science, 72 (1), ISSN:1351-0754, ISSN:1365-2389
23. Microhydrological Niches in Soils: How Mucilage and EPS Alter the Biophysical Properties of the Rhizosphere and Other Biological Hotspots
- Author
-
Benard, Pascal, Zarebanadkouki, Mohsen, Brax, Mathilde, Kaltenbach, Robin, Jerjen, Iwan, Marone, Federica, Couradeau, Estelle, Felde, Vincent J.M.N.L., Kaestner, Anders, and Carminati, Andrea
- Subjects
13. Climate action ,15. Life on land - Abstract
Plant roots and bacteria are capable of buffering erratic fluctuations of water content in their local soil environment by releasing a diverse, highly polymeric blend of substances (e.g. extracellular polymeric substances [EPS] and mucilage). Although this concept is well accepted, the physical mechanisms by which EPS and mucilage interact with the soil matrix and determine the soil water dynamics remain unclear. High-resolution X-ray computed tomography revealed that upon drying in porous media, mucilage (from maize [Zea mays L.] roots) and EPS (from intact biocrusts) form filaments and two-dimensional interconnected structures spanning across multiple pores. Unlike water, these mucilage and EPS structures connecting soil particles did not break up upon drying, which is explained by the high viscosity and low surface tension of EPS and mucilage. Measurements of water retention and evaporation with soils mixed with seed mucilage show how these one- and two-dimensional pore-scale structures affect macroscopic hydraulic properties (i.e., they enhance water retention, preserve the continuity of the liquid phase in drying soils, and decrease vapor diffusivity and local drying rates). In conclusion, we propose that the release of viscous polymeric substances and the consequent creation of a network bridging the soil pore space represent a universal strategy of plants and bacteria to engineer their own soil microhydrological niches where stable conditions for life are preserved., Vadose Zone Journal, 18 (1), ISSN:1539-1663
24. Microhydrological Niches in Soils : How Mucilage and EPS Alter the Biophysical Properties of the Rhizosphere and Other Biological Hotspots
- Author
-
Benard, Pascal, Zarebanadkouki, Mohsen, Brax, Mathilde, Kaltenbach, Robin, Jerjen, Iwan, Marone, Federica, Couradeau, Estelle, Felde, J. M. N. L., Kaestner, Anders, and Carminati, Andrea
- Subjects
13. Climate action ,15. Life on land - Abstract
Plant roots and bacteria are capable of buffering erratic fluctuations of water content in their local soil environment by releasing a diverse, highly polymeric blend of substances (e.g. extracellular polymeric substances [EPS] and mucilage). Although this concept is well accepted, the physical mechanisms by which EPS and mucilage interact with the soil matrix and determine the soil water dynamics remain unclear. High-resolution X-ray computed tomography revealed that upon drying in porous media, mucilage (from maize [Zea mays L.] roots) and EPS (from intact biocrusts) form filaments and two-dimensional interconnected structures spanning across multiple pores. Unlike water, these mucilage and EPS structures connecting soil particles did not break up upon drying, which is explained by the high viscosity and low surface tension of EPS and mucilage. Measurements of water retention and evaporation with soils mixed with seed mucilage show how these one- and two-dimensional pore-scale structures affect macroscopic hydraulic properties (i.e., they enhance water retention, preserve the continuity of the liquid phase in drying soils, and decrease vapor diffusivity and local drying rates). In conclusion, we propose that the release of viscous polymeric substances and the consequent creation of a network bridging the soil pore space represent a universal strategy of plants and bacteria to engineer their own soil microhydrological niches where stable conditions for life are preserved.
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