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Physical characterisation of chia mucilage polymeric gel and its implications on rhizosphere science - integrating imaging, MRI, and modelling to gain insights into plant and microbial amended soils

Physical characterisation of chia mucilage polymeric gel and its implications on rhizosphere science - integrating imaging, MRI, and modelling to gain insights into plant and microbial amended soils
Physical characterisation of chia mucilage polymeric gel and its implications on rhizosphere science - integrating imaging, MRI, and modelling to gain insights into plant and microbial amended soils
Root-secreted mucilage and microbial produced extracellular polymeric substances (EPS) modify soil physical and biogeochemical processes. Most studies infer the effects of these polymeric substances from soil bulk behaviour rather than investigating the pore scale. This investigation quantified the isolated physical behaviour of mucilage in a simplified pore-scale setup. We placed drops of mucilage of different concentrations between two flat surfaces to form liquid bridges and monitored their drying using optical imaging and magnetic resonance imaging (MRI). We used our observations to validate a polymer-based multi-phase model that characterises the gel-water-air interactions. In the experiments, while pure water liquid bridges rupture, the mucilage buckled under drying, but maintained connection between the surfaces. MRI showed more water was lost from the central region in the middle of the two plates. In the model, mucilage gel accumulated near the boundaries where surface adhesion occurs. The modelled accumulation times overlapped with monitored bridge buckling for the different concentrations, showing the model can predict the observed transition at which the mixture no longer behaves like a pure liquid. Results suggest that the earlier phase transitions observed for higher mucilage concentrations show a potential mechanism for the greater drought tolerance for plant roots and increase the soil water holding capacity. Furthermore, we discuss potential applications of our model for describing the impacts that microbial biofilms may have on soil structure along with impacts of soil fauna on soil physical functions.
EPS, fluid mechanics, mucilage, nuclear magnetic resonance, polymer physics, rhizosphere, soil
0038-0717
Williams, Katherine
a13f30b4-2f53-4a14-ad38-c733923a6450
Ruiz, Siul Aljadi
d79b3b82-7c0d-47cc-9616-11d29e6a41bd
Petroselli, Chiara
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Walker, N
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Mckay Fletcher, Daniel
db06e7e0-69af-4fa2-89b3-26f6599e43d4
Pileio, Giuseppe
13f78e66-0707-4438-b9c9-6dbd3eb7d4e8
Roose, Tiina
3581ab5b-71e1-4897-8d88-59f13f3bccfe
Williams, Katherine
a13f30b4-2f53-4a14-ad38-c733923a6450
Ruiz, Siul Aljadi
d79b3b82-7c0d-47cc-9616-11d29e6a41bd
Petroselli, Chiara
19266726-2dc0-4790-af77-7ccdc45865eb
Walker, N
2b07a7ad-150d-4434-9972-7b234804e209
Mckay Fletcher, Daniel
db06e7e0-69af-4fa2-89b3-26f6599e43d4
Pileio, Giuseppe
13f78e66-0707-4438-b9c9-6dbd3eb7d4e8
Roose, Tiina
3581ab5b-71e1-4897-8d88-59f13f3bccfe

Williams, Katherine, Ruiz, Siul Aljadi, Petroselli, Chiara, Walker, N, Mckay Fletcher, Daniel, Pileio, Giuseppe and Roose, Tiina (2021) Physical characterisation of chia mucilage polymeric gel and its implications on rhizosphere science - integrating imaging, MRI, and modelling to gain insights into plant and microbial amended soils. Soil Biology and Biochemistry, 162, [108404]. (doi:10.1016/j.soilbio.2021.108404).

Record type: Article

Abstract

Root-secreted mucilage and microbial produced extracellular polymeric substances (EPS) modify soil physical and biogeochemical processes. Most studies infer the effects of these polymeric substances from soil bulk behaviour rather than investigating the pore scale. This investigation quantified the isolated physical behaviour of mucilage in a simplified pore-scale setup. We placed drops of mucilage of different concentrations between two flat surfaces to form liquid bridges and monitored their drying using optical imaging and magnetic resonance imaging (MRI). We used our observations to validate a polymer-based multi-phase model that characterises the gel-water-air interactions. In the experiments, while pure water liquid bridges rupture, the mucilage buckled under drying, but maintained connection between the surfaces. MRI showed more water was lost from the central region in the middle of the two plates. In the model, mucilage gel accumulated near the boundaries where surface adhesion occurs. The modelled accumulation times overlapped with monitored bridge buckling for the different concentrations, showing the model can predict the observed transition at which the mixture no longer behaves like a pure liquid. Results suggest that the earlier phase transitions observed for higher mucilage concentrations show a potential mechanism for the greater drought tolerance for plant roots and increase the soil water holding capacity. Furthermore, we discuss potential applications of our model for describing the impacts that microbial biofilms may have on soil structure along with impacts of soil fauna on soil physical functions.

Text
Chia_mucilage_paper_nomarkup_figsend - Accepted Manuscript
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More information

Accepted/In Press date: 27 August 2021
e-pub ahead of print date: 2 September 2021
Keywords: EPS, fluid mechanics, mucilage, nuclear magnetic resonance, polymer physics, rhizosphere, soil

Identifiers

Local EPrints ID: 451339
URI: http://eprints.soton.ac.uk/id/eprint/451339
ISSN: 0038-0717
PURE UUID: 31f56caa-a14c-4291-b817-0f97e704f3b3
ORCID for Katherine Williams: ORCID iD orcid.org/0000-0001-6827-9261
ORCID for Daniel Mckay Fletcher: ORCID iD orcid.org/0000-0001-6569-2931
ORCID for Giuseppe Pileio: ORCID iD orcid.org/0000-0001-9223-3896
ORCID for Tiina Roose: ORCID iD orcid.org/0000-0001-8710-1063

Catalogue record

Date deposited: 21 Sep 2021 16:31
Last modified: 23 Sep 2021 05:31

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Contributors

Author: Chiara Petroselli
Author: N Walker
Author: Daniel Mckay Fletcher ORCID iD
Author: Giuseppe Pileio ORCID iD
Author: Tiina Roose ORCID iD

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