Time persistence as a source of large-scale fluctuations in growing tissues
Antoine Fruleux (LPTMS)
Due to the current health situation, this week’s seminar will be held online only:
Meeting ID: 962 5450 7481
In biological tissues, the space and time variations of certain properties appear greatly random. Many recent studies investigate the impact of this randomness on the development of tissues. Such studies aim, for example, at understanding its role in the self-organization of tissues or at describing how the cellular responses it induces impact the developments of organs. To better understand the role played by random fluctuations during morphogenesis, a first step is to have a better characterization of their properties. Using theoretical modeling, we predicted that the spatial extend of fluctuations is large and results from the combined effects of growth and the fluctuation’s time persistence. This prediction, which generally applies to any expending media, has strong consequences when considering biological tissues. It notably implies long ranged space correlations, which tend to give rise to random organ shapes, in contradiction with the observed robustness of many organ shapes. An explanation for this apparent paradox may be found in the fine tuning of some of the tissue properties to minimize the heterogeneity of organs, and we investigated the influence of the tissue’s response to the mechanical stress on the organ shape. Our model’s predictions prompted us to analyze the spectra of fluctuations in growing tissues, developing a novel approach that is applicable to geometrically disordered materials. After introducing the main predictions of the model, I will present the experimental evidences supporting them in plant tissues. Finally, I will express the questions raised by our findings.