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Accueil du site > Emplois et Stages > Sujets de Thèses > PhD Project : « Unraveling the physical basis of morphogenesis in plants through a three-dimensional map of mechanical properties »

PhD Project : « Unraveling the physical basis of morphogenesis in plants through a three-dimensional map of mechanical properties »

Institute :

Laboratoires Joliot-Curie and Reproduction et Développement des Plantes, ENS Lyon

PhD supervisor :

Arezki BOUDAOUD

Email adress and phone number :

Arezki.Boudaoud(A)ens-lyon.fr, 04 72 72 88 75

Team members involved :

Olivier HAMANT and Arezki BOUDAOUD

Project description :

The emergence of shape in an organism involves changes in its structural elements — adding new materials and remodeling old materials. In this context, morphogenesis appears as a physical process guided by the activity of cells. Therefore the investigation of morphogenesis must also address the mechanical properties of the structural elements of the organism during its development. Plants are perfectly suited for such an investigation, as their shape is mostly imposed by the stiff cell walls that surround cells and by the osmotic pressure that inflates cells. The main goal of the project is to establish a three-dimensional map of the mechanical properties of the plant tissues. On the one hand, the use of an atomic microscope will enable the measurement of elastic properties and osmotic pressure for epidermal cells. On the other hand, micromechanical manipulations combined with confocal imaging will allow to determine the strain field under loading and to infer the relative value of elastic moduli in three dimensions. The team has already obtained preliminary results showing the feasibility of these approaches. Three-dimensional maps will be first obtained for cylindrical organs (stems and roots), for which the interpretation is easier, and then the method will be applied to organogenetic regions (the stem apex). The next step will be to compare measurements with the knowledge on the genetic identity of cells and on growth. For instance, does the genetic identity correspond to a mechanical identity ? Will a softer region grow more ? More generally, the PhD work will help building a new framework for morphogenesis.