Team : MECA

PhD student :  GOURICHON Lucie

Thesis supervisors : BADEL Eric  (Université Clermont Auvergne/INRAe, PIAF, Clermont-Ferrand), Bruno Clair (Université Montpellier/CNRS, LMGC, Montpellier)

Dates : October 2023 - October 2026

Description

More than half of terrestrial biomass comes from cambial activity, mainly in the form of wood (Bond-Lamberty and Thomson 2010). Located just beneath the bark, the cambium is the secondary meristem responsible for producing two tissues that are essential to trees: phloem (bast or inner bark) on the outside and xylem (wood) on the inside (Groover 2016). In a pivotal century, where choices must be made to prevent climate disasters, the process of wood formation is proving to be an important CO2 sink throughout the life of a tree (Pan et al. 2011). It is therefore crucial to understand the fundamental processes of this immense natural carbon storage factory that is cambial growth, as it determines both the quantity and quality of the wood produced.

Cambial activity defines the cellular organisation of wood. In practice, this mechanism is governed by two main factors: the tree's genetic makeup and the growing conditions to which it is subjected. Numerous studies have sought to establish a link, often statistical, between environmental factors and secondary tree growth (Buttò et al. 2021, Rathgeber et al. 2022), but few have focused on the physical mechanisms that govern its functioning. This thesis aims to understand how the local and specific mechanical environment of the cambium, confined between the rigid xylem and the bark (including the phloem), can play a decisive role in the processes of cell division and expansion, made possible by the action of turgor pressure. This work is part of the ANR CEMACam project.