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

Dyson, Rosemary J.; Vizcay-Barrena, Gema; Band, Leah R.; Fernandes, Anwesha N.; French, Andrew P.; Fozard, John A.; Hodgman, T. Charlie; Kenobi, Kim; Pridmore, Tony P.; Stout, Michael; Wells, Darren M.; Wilson, Michael H.; Bennett, Malcolm J.; Jensen, Oliver E.

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.

Citation

Dyson, R. J., Vizcay-Barrena, G., Band, L. R., Fernandes, A. N., French, A. P., Fozard, J. A., Hodgman, T. C., Kenobi, K., Pridmore, T. P., Stout, M., Wells, D. M., Wilson, M. H., Bennett, M. J., & Jensen, O. E. (2014). Mechanical modelling quantifies the functional importance of outer tissue layers during root elongation and bending. New Phytologist, 202(4), 1212-1222. https://doi.org/10.1111/nph.12764

• Journal Article Type: Article
• Acceptance Date: Feb 2, 2014
• Online Publication Date: Mar 18, 2014
• Publication Date: Jan 1, 2014
• Deposit Date: Jun 29, 2017
• Publicly Available Date: Jun 29, 2017
• Journal: New Phytologist
• Print ISSN: 0028-646X
• Electronic ISSN: 1469-8137
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 202
• Issue: 4
• Pages: 1212-1222
• DOI: https://doi.org/10.1111/nph.12764
• Keywords: Arabidopsis thaliana, Elongation, Extensibility, Gravitropism, Mechanical modelling, Multiscale
• Public URL: https://nottingham-repository.worktribe.com/output/728980
• Publisher URL: https://doi.org/10.1111/nph.12764
• Additional Information: Published Online: 2014-03-18
• Contract Date: Jun 29, 2017