Modelling the Mechanical Interactions between Plant Root Growth and the Soil

Description of the thesis subject

This PhD project focuses on developing a multiscale computational model to understand plant root growth in interaction with soil. It combines morphoelasticity (root response to mechanical stimuli [4]) and elastoplasticity (inelastic soil behaviour). The aim is to connect a root environment model, capturing detailed root growth and root-soil interaction, to a 3D model of the whole root capturing its large-scale behaviour (coiling and skewing) [4], which is influenced by what happens at the tip. The resulting multiscale model is used to incorporate the root’s responses to gravity and touch. The PhD student will develop a model at LIPhy (see e.g. [2], [3]) and work with 3SR’s experimental team, whose experiments (see e.g. [1]) will be used to validate the model predictions. Studying the interaction of a growing root against an elastoplastic soil, where the root generates stress and soil relaxes it, is a novel perspective at the frontier between mechanics and biophysics in which competing deformation mechanisms strive for mutual equilibrium. This new understanding may lead to the development of bio-inspired self-propelled sensors moving in soil for agriculture or civil engineering applications, as well as the reinforcement of soils by roots to stabilise them against erosion or for construction. 

References 

[1] Floriana Anselmucci, Edward Andò, Gioacchino Viggiani, Nicolas Lenoir, Chloé Arson, and Luc Sibille. “Imaging local soil kinematics during the first days of maize root growth in sand”. In: Scientific reports 11.1 (2021), p. 22262. https://doi.org/10.1038/s41598-021-01056-1 . 

[2] Finn Box, Alexander Erlich, Jian H Guan, and Chris Thorogood. “Gigantic floating leaves occupy a large surface area at an economical material cost”. In: Science Advances 8.6 (2022), eabg3790. https://doi.org/10.1126/sciadv.abg3790 . 

[3] Alexander Erlich and Pierre Recho. “Mechanical feedback in regulating the size of growing multicellular spheroids”. In: Journal of the Mechanics and Physics of Solids (2023), p. 105342. https://doi.org/10.1016/j.jmps.2023.105342 . 

[4] Amir Porat, Arman Tekinalp, Yashraj Bhosale, Mattia Gazzola, and Yasmine Meroz. “On the mechanical origins of waving, coiling and skewing in Arabidopsis thaliana roots”. In: Proceedings of the National Academy of Sciences 121.11 (2024), e2312761121. doi: https://doi.org/10.1073/pnas.2312761121 .

Work environment

Grenoble is the unique conjunction of a well-established university with world-class research groups, within a great mountain landscape. 

The LIPhy is a mixed research unit CNRS - UGA. It is  a highly interdisciplinary laboratory (solid/fluid mechanics, statistical physics, optics, applied mathematics, biology) mande up of nine groups. 

You will be part of the group MC2 (Cell Mechanics in Complex Media) and you will be supervised by Alexander Erlich and Pierre Recho as part of the CNRS 80 PRIME programme, funded for three years. 

Further information

This project will combine cutting-edge experiments led by C. Viggiani and L. Sibille and sophisticated modelling/simulation under the guidance of A. Erlich and P. Recho, with an aim to understand the fundamental mechanics governing root-soil interactions. High-performance computing clusters are available. 

The candidate should have a background in mechanical engineering, physics, or applied mathematics. The ideal candidate has experience in coding numerical solutions to partial differential equations via the finite element method / finite differences schemes and programming skills in Mathematica, Matlab, Python, or Julia. Additionally, modelling skills in a finite element framework such as Comsol Multiphysics are highly desirable. 

The gross salary is 2135 € / month.

If you would like more information, please contact us at alexander.erlich@univ-grenoble-alpes.fr .

How to apply

To apply, you will need to send us your CV and covering letter.

If you wish, you can also send us :

• an example of academic writing, a dissertation chapter or a draft article

• the names and contact details of people we could contact for references.

Please note that applications must be submitted via the CNRS job portal, via the following link: https://emploi.cnrs.fr/Offres/Doctorant/UMR5588-ALEERL-004/Default.aspx 

No applications will be accepted by e-mail.

Applications will be accepted until the position is filled.