Thématiques de recherches

Physico-chemical defenses of Mediterranean forests to cope with climate change : example of (Quercus pubescens)

Current forecasts predict that global warming will modify the physiology of trees, impacting their growth and therefore their survival. In the Mediterranean region, climate models predict a reduction of about 30% in annual precipitation by the end of the twenty-first century, with longer drought periods and a recurrence of dry years. These rapid changes may therefore impact forests by limiting their ecosystem and societal services.

My PhD thesis is part of this context and aims to evaluate the physiological stress of downy oaks (Quercus pubescens) exposed to restrictions of precipitation (-30%) and the different defenses (physical and metabolic) that take place at the leaf level to cope with water stress (see “research area" section)

The project

The METAPHORES project (METAbolomic and MorPHOlogical adaptations of a Downy oak forest to long-term rain REStriction in natura) aims to identify leaf physico-chemical strategies of downy oaks to adapt to recurrent water deficit after 8-9 years of restriction of precipitations in natural environment under Mediterranean climate.
The PhD is funded by the MITI-CNRS (Mission pour les Initiatives Transverses et Interdisciplinaires) grant of 200K € and brings together several scientific actors from various fields such as radical chemistry, optical physics, plant physiology, metabolomic and ecology.
As listed below, several scientific partners and collaborators contribute to the interdisciplinarity of this project :
Partners :
-  Dr Michel HAVAUX and Brigitte KSAS (CEA, BIAM, Cadarache)
-  Dr Sophie BRASSELET (Institut Fresnel, Marseille)
-  Dr Béatrice TUCCIO-LAURICELLA (Institut de Chimie Radicalaire, Marseille)
Collaborators :
-  Dr Guillermo GEA IZQUIERDO (INIA, CIFOR, Madrid)
-  Dr Guillaume LEDUC (Cerege, Aix-en-Provence)

The experimental site

Leaf sampling is done in the Quercus pubescens forest at the O3HP (Oak Observatory at the OHP) experimental site located 100 km north of Marseille (https://www.eccorev.fr/spip.php?rubrique8). On this site, an experimental rain exclusion system allows to change, on a given plot of land comprising several dozen trees, the precipitation regime by modifying the summer drought period.
The plot subjected to restriction of precipitations is thus compared to an adjacent « control » plot. The aim is to reduce the total annual precipitation by 30% simulating an aggravated and recurrent water stress (see pictures). The whole area is equipped with a network of sensors (temperature and humidity at ground level and in the canopy, sap flow, etc.).

Reasearch area of METAPHORES project