Ref HAL: hal-00867285_v3
Ref Arxiv: 1309.7432
DOI: 10.1140/epje/i2015-15033-4
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40 Citations
Résumé:

The understanding of morphogenesis in living organisms has been renewed by tremendous progressin experimental techniques that provide access to cell-scale, quantitative information both on theshapes of cells within tissues and on the genes being expressed. This information suggests that ourunderstanding of the respective contributions of gene expression and mechanics, and of their crucialentanglement, will soon leap forward. Biomechanics increasingly benefits from models, which assistthe design and interpretation of experiments, point out the main ingredients and assumptions, andultimately lead to predictions. The newly accessible local information thus calls for a reflectionon how to select suitable classes of mechanical models. We review both mechanical ingredientssuggested by the current knowledge of tissue behaviour, and modelling methods that can helpgenerate a rheological diagram or a constitutive equation. We distinguish cell scale (“intra-cell”)and tissue scale (“inter-cell”) contributions. We recall the mathematical framework developpedfor continuum materials and explain how to transform a constitutive equation into a set of partialdifferential equations amenable to numerical resolution. We show that when plastic behaviour isrelevant, the dissipation function formalism appears appropriate to generate constitutive equations;its variational nature facilitates numerical implementation, and we discuss adaptations needed in thecase of large deformations. The present article gathers theoretical methods that can readily enhancethe significance of the data to be extracted from recent or future high throughput biomechanicalexperiments.

Commentaires: 33 pages, 20 figures. This version (26 Sept. 2015) contains a few corrections to the published version, all in Appendix D.2 devoted to large deformations. An Erratum to the original article, containing the present corrections, was published under the following reference: Eur. Phys. J. E 38 115 (2015).

Ref HAL: hal-01236550_v1
DOI: 10.17660/ActaHortic.2015.1068.6
WoS: 000358012400006
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1 Citation
Résumé:

Understanding the controlling factors of fruit quality development is challenging, because fruit quality is the result of the interplay between physical and physiological processes that are under the control of genes and the environment. Although process-based models have been used to make significant progress in understanding these factors, they to a large extent ignore the shape and internal structure of the fruit. To help investigate effects of fruit shape and internal structure on quality, the aim of this work is to create a 3D virtual fruit model that integrates fruit structure and function with growth governed by environmental inputs. For this purpose, we are creating a modelling pipeline that includes the following steps: creation of a 3D volumetric mesh of the internal and external fruit structure, calculation of the fruit’s physical properties from the resulting mesh, and integration of aspects of fruit physiology into the 3D structure. We have applied this pipeline to study tomato fruit (Solanum lycopersicum) by constructing 3D volumetric meshes from two images of perpendicular fruit slices and from MRI data, and integrating water and carbon transport processes into one of these meshes. To illustrate the tomato model, we performed a simulation of one season’s of the fruit’s growth, and compared the results with an already published process-based tomato fruit model. The results of the two models were in general agreement, but our model provided additional information on the internal properties of the fruit, such as a gradient in sugar concentration. Once the model is calibrated and evaluated, our approach will be suitable for studying the effects of internal fruit heterogeneity and overall shape on fruit quality development.