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X-ray Computed Tomography and image-based modelling of plant, root and soil systems, for better understanding of phosphate uptake

X-ray Computed Tomography and image-based modelling of plant, root and soil systems, for better understanding of phosphate uptake
X-ray Computed Tomography and image-based modelling of plant, root and soil systems, for better understanding of phosphate uptake
A major constraint to crop growth is the poor bioavailability of edaphic nutrients, especially phosphate (P). Improving the nutrient acquisition efficiency of crops is crucial in addressing pressing global food-security issues arising from increasing world population, reduced fertile land and changes in the climate. Despite the undoubted importance of root architecture and root/soil interactions to nutrient uptake, there is a lack of approaches for quantifying plant roots non-invasively at all scales. Mathematical models have allowed our understanding of root and soil interactions to be improved, but are almost invariably reliant on idealised geometries or virtual root growth models. In order to improve phenotyping of advantageous traits for low-P conditions and improve the accuracy of root growth and uptake models, more sophisticated and robust approaches to in vivo root and soil characterisation are needed. Microfocus X-ray Computed Tomography (?-CT) is a methodology that has shown promise for noninvasive imaging of roots and soil at various scales. However, this potential has not been extended to consideration of either very small (rhizosphere scale) or large (mature root system scale) samples. This thesis combines discovery experiments and method development in order to achieve two primary objectives:

• The development of more robust, well-described approaches to root and soil ?-CT imaging. Chapters 2 and 3 explore the potential of clinical contrasting methods in root investigation, and show how careful consideration of imaging parameters combined with development of user invariant image-processing protocol can improve measurement of macro-porous volume fraction, a key soil parameter.

• Chapter 4 develops an assay for first-time 3D imaging of root hairs in situ within the rhizosphere. The resulting data is used to parameterise an explicit P uptake model at the hair scale, suggesting a different contribution of hairs to uptake than was predicted using idealised geometries. Chapter 5 then extends the paradigm for root hair imaging and model generation, building a robust, modular workflow for investigating P dynamics in the rhizosphere that can accommodate non-optimal soil-water states.
University of Southampton
Keyes, Samuel
ed3ee62b-e257-4b92-922c-023b232e8145
Keyes, Samuel
ed3ee62b-e257-4b92-922c-023b232e8145
Sinclair, Ian
6005f6c1-f478-434e-a52d-d310c18ade0d
Marchant, Alan
3e54d51c-53b0-4df0-b428-2e73b071ee8e
Roose, Tina
56ea125d-ea3b-4b7c-8af0-9e1c48b2489c

(2013) X-ray Computed Tomography and image-based modelling of plant, root and soil systems, for better understanding of phosphate uptake. University of Southampton, Engineering and the Environment, Doctoral Thesis, 262pp.

Record type: Thesis (Doctoral)

Abstract

A major constraint to crop growth is the poor bioavailability of edaphic nutrients, especially phosphate (P). Improving the nutrient acquisition efficiency of crops is crucial in addressing pressing global food-security issues arising from increasing world population, reduced fertile land and changes in the climate. Despite the undoubted importance of root architecture and root/soil interactions to nutrient uptake, there is a lack of approaches for quantifying plant roots non-invasively at all scales. Mathematical models have allowed our understanding of root and soil interactions to be improved, but are almost invariably reliant on idealised geometries or virtual root growth models. In order to improve phenotyping of advantageous traits for low-P conditions and improve the accuracy of root growth and uptake models, more sophisticated and robust approaches to in vivo root and soil characterisation are needed. Microfocus X-ray Computed Tomography (?-CT) is a methodology that has shown promise for noninvasive imaging of roots and soil at various scales. However, this potential has not been extended to consideration of either very small (rhizosphere scale) or large (mature root system scale) samples. This thesis combines discovery experiments and method development in order to achieve two primary objectives:

• The development of more robust, well-described approaches to root and soil ?-CT imaging. Chapters 2 and 3 explore the potential of clinical contrasting methods in root investigation, and show how careful consideration of imaging parameters combined with development of user invariant image-processing protocol can improve measurement of macro-porous volume fraction, a key soil parameter.

• Chapter 4 develops an assay for first-time 3D imaging of root hairs in situ within the rhizosphere. The resulting data is used to parameterise an explicit P uptake model at the hair scale, suggesting a different contribution of hairs to uptake than was predicted using idealised geometries. Chapter 5 then extends the paradigm for root hair imaging and model generation, building a robust, modular workflow for investigating P dynamics in the rhizosphere that can accommodate non-optimal soil-water states.

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More information

Published date: 31 December 2013
Organisations: University of Southampton, Engineering Mats & Surface Engineerg Gp, Bioengineering Group

Identifiers

Local EPrints ID: 364786
URI: http://eprints.soton.ac.uk/id/eprint/364786
PURE UUID: d7ca8114-be62-4b7a-a442-65c1f0d246a9
ORCID for Samuel Keyes: ORCID iD orcid.org/0000-0002-4129-2228

Catalogue record

Date deposited: 02 Jun 2014 11:06
Last modified: 06 Jun 2018 12:31

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Contributors

Author: Samuel Keyes ORCID iD
Thesis advisor: Ian Sinclair
Thesis advisor: Alan Marchant
Thesis advisor: Tina Roose

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