Mechanical modelling quantifies the functional importance of outer tissue layers during root elongation and bending

Dyson, Rosemary J. and Vizcay-Barrena, Gema and Band, Leah R. and Fernandes, Anwesha N. and French, Andrew P. and Fozard, John A. and Hodgman, T. Charlie and Kenobi, Kim and Pridmore, Tony P. and Stout, Michael and Wells, Darren M. and Wilson, Michael H. and Bennett, Malcolm J. and Jensen, Oliver E. (2014) Mechanical modelling quantifies the functional importance of outer tissue layers during root elongation and bending. New Phytologist, 202 (4). pp. 1212-1222. ISSN 1469-8137

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Abstract

Root elongation and bending require the coordinated expansion of multiple cells of different types. These processes are regulated by the action of hormones that can target distinct cell layers. We use a mathematical model to characterise the influence of the biomechanical properties of individual cell walls on the properties of the whole tissue.

Taking a simple constitutive model at the cell scale which characterises cell walls via yield and extensibility parameters, we derive the analogous tissue-level model to describe elongation and bending. To accurately parameterise the model, we take detailed measurements of cell turgor, cell geometries and wall thicknesses.

The model demonstrates how cell properties and shapes contribute to tissue-level extensibility and yield. Exploiting the highly organised structure of the elongation zone (EZ) of the Arabidopsis root, we quantify the contributions of different cell layers, using the measured parameters. We show how distributions of material and geometric properties across the root cross-section contribute to the generation of curvature, and relate the angle of a gravitropic bend to the magnitude and duration of asymmetric wall softening.

We quantify the geometric factors which lead to the predominant contribution of the outer cell files in driving root elongation and bending.

Item Type: Article
Keywords: Arabidopsis thaliana, Elongation, Extensibility, Gravitropism, Mechanical modelling, Multiscale
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Biosciences
Identification Number: 10.1111/nph.12764
Depositing User: Eprints, Support
Date Deposited: 29 Jun 2017 11:58
Last Modified: 12 Oct 2017 23:51
URI: http://eprints.nottingham.ac.uk/id/eprint/43869

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