Jérôme Chopard

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Plants continuously generate new organs through the activity of populations of stem cells called meristems. The shoot apical meristem initiates leaves, flowers, and lateral meristems in highly ordered, spiralled, or whorled patterns via a process called phyllotaxis. It is commonly accepted that the active transport of the plant hormone auxin plays a major(More)
In this paper, we present PlantGL, an open-source graphic toolkit for the creation, simulation and analysis of 3D virtual plants. This C++ geometric library is embedded in the Python language which makes it a powerful user-interactive platform for plant modeling in various biological application domains. PlantGL makes it possible to build and manipulate(More)
As multicellular organisms grow, positional information is continually needed to regulate the pattern in which cells are arranged. In the Arabidopsis root, most cell types are organized in a radially symmetric pattern; however, a symmetry-breaking event generates bisymmetric auxin and cytokinin signaling domains in the stele. Bidirectional cross-talk(More)
Actinorhizal symbioses are mutualistic interactions between plants and the soil bacteria Frankia that lead to the formation of nitrogen-fixing root nodules. Little is known about the signaling mechanisms controlling the different steps of the establishment of the symbiosis. The plant hormone auxin has been suggested to play a role. Here we report that auxin(More)
The link between genetic regulation and the definition of form and size during morphogenesis remains largely an open question in both plant and animal biology. This is partially due to the complexity of the process, involving extensive molecular networks, multiple feedbacks between different scales of organization and physical forces operating at multiple(More)
Camilo La Rota,a Jérôme Chopard,b Pradeep Das,c Sandrine Paindavoine,c Frédérique Rozier,c Etienne Farcot,b Christophe Godin,b Jan Traas,c and Françoise Monégerc,1 a Laboratoire de l’Informatique du Parallélisme, Ecole Normale Supérieure Lyon, 69364 Lyon, cedex 07, France b Institut National de Recherche en Informatique et Automatique Project Team Virtual(More)
Because of the difficulty and time involved in making exhaustive measurements of the geometric parameters of large tree crowns, simplifying hypotheses are often used in 3D virtual plant modelling, but the effects on the radiation balance of each approximation are rarely assessed. Three hybrid walnut trees aged 7–9 years were digitized to analyse the effect(More)
Shoot apical meristems are small groups of rapidly dividing, undifferentiated cells, which generate all aerial parts of the plants. Recently, spectacul ar advances in molecular biology and genetics have provided a wealth of information on meristem functioning. However, the amount of available information is now such, that an integrated view is no longer(More)