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Dernière mise à jour : Mai 2018

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MECA (Effects of MEChanical stresses on the Activity of growth zones )

 Leader: Dr. Nathalie LEBLANC-FOURNIER


MECA is an interdisciplinary group including biomechanicians, ecophysiologists and molecular physiologists in a project of Integrative Plant Bio- Mechanics (i.e. biomechanics and mechanobiology). 8 permanent scientific researchers (3 from INRA and 5 from the Blaise Pascal University), 1 post-doc and 4 PhD students are currently involved in this project that focuses on the general question " how do trees stand upright for so long while growing and displaying their architecture in a mechanically challenging environment ?".It has been shown in the recent years that the function of mechanical stability is active and fully coupled with growth. Indeed the size and mechanical attributes of stems (height, girth, tissue stiffness, anchorage by the root system) are controlled by the mechanical loads experienced by the plant through the process of thigmomorphogenesis. Moreover the plant posture is controlled by active straightening processes including gravitropism, that enable the plant to recover it habit upon mechanical hazards (as long as wounding is moderate). And only the interplay of these two processes can produce the long lasting stability of plant architecture through its plastic acclimation to the mechanical environment. In the context of the forecast of increasing storms frequency due to Global Climatic Changes, a better understanding of this interplay is necessary. Additionally, environmental-friendly techniques can be derived in arboriculture (branch arching and bending) and for the improved production of tree seedlings in the field or in greenhouse without using chemical growth substances. However, very little is still known about the underlying mechanisms and their consequences for plant growth.

A key point in these two processes is the mechanoperception of strains and inclination angles induced by gravity, wind or manipulations. We are developing biomechanical models of mechanoperception and response, as tools to identify, rank and formalize the physical and biological mechanisms involved. Focus is put on the identification of the internal variables that are perceived, and on the mechanistic study of the accommodation of mechanosensitivity to the loading regimes. And genes involved in the early steps of mechanoperception are under study, in particular transcription factors.

Such Integrative Bio-Mechanical studies involves complementary methods such as morphometrics (continuous growth measurements, 3D digitizing), structure mechanics (controlled loading, mechanical tests, modeling), molecular biology and bioinformatics.

Targeted applications belongs to the areas of the managements of forest, arboricultural and even urban trees (mechanical security and growth, pruning or thinning, staking, arching ?) as well of the production of mechanically acclimated tree seedlings.


Presentation of MECA methods

©Photos PIAF