Teams : MEA, Sureau

Project manager :   AMEGLIO Thierry

Project link : https://anr.fr/Projet-ANR-20-CE91-0008

Présentation

Frost stress is the main factor determining the distribution of plants at high latitudes and high altitudes. Climate change will not only lead to changes in precipitation patterns and earlier snowmelt, but also to increased climatic extremes, which could lead to increased winter drought and frost stress in woody plants. Frost has been shown to affect living and dead wood tissues and alter their hydraulic function by inducing emboli. Emboli (air bubbles trapped in wood tissues) block water transport and thus impede water supply to the crown. Plants must cope with this hydraulic limitation by repairing dysfunctional wood or by forming new woody tissue.
Building on the "Acoufreeze" project, which focused on the processes and dynamics during ice formation in wood, the "Acoufollow" project aims to better understand how plants overcome wood dysfunction following frost stress. The repair of frost-induced embolism will be investigated in six contrasting model species (Acer pseudoplatanus, Larix decidua, Picea abies, Juniperus communis, Rhododendron ferrugineum, Sorbus aucuparia) both in temperature-controlled chamber experiments and in the field. At the high-altitude field sites, monitoring under natural conditions and snow manipulation experiments are planned. The analyses are based on ultrasonic acoustic emission and stem diameter measurements, wood core measurements, and various complementary methods (wood pressure probes, infrared thermography, hydraulics, micrometeorology, etc.). The use of ultrasonic systems and rod diameter measurement will be particularly difficult here in harsh winter conditions.
Experiments, numerical simulations, and field monitoring are expected to unravel the complex spatiotemporal dynamics of wood pressure during freeze-thaw cycles and embolism recovery. Snow monitoring and manipulation approaches will allow the analysis of embolism formation and repair under highly stressful environmental conditions and varying snow depth situations. Accordingly, relevant climate parameters will be linked to the multi-decadal growth responses of the studied species to enable projections of future critical conditions for wood dysfunction and repair.The project is based on a cooperation between UMR PIAF (INRA-Université Clermont Auvergne, Clermont-Ferrand, France), Geolab (CNRS-Université Clermont Auvergne, Clermont-Ferrand, France), the Department of Botany (University of Innsbruck, Austria) and the Department of Botany of BOKU University (University of Natural Resources and Life Sciences, Vienna, Austria). The close collaboration of the partners involved, who bring their expertise in different methodological and scientific aspects, will allow a better understanding of the underlying processes during and after freezing of plant wood and its importance for plants in a changing climate. The results will provide a better understanding of freezing in the studied species and its relevance for plant life at high altitudes, but also improve our knowledge of frost tolerance and resilience of plants in general.

Partners

GEOLAB LABORATOIRE DE GÉOGRAPHIE PHYSIQUE ET ENVIRONNEMENTALE
UIBK University of Innsbruck / Department of Botany

Funding source

Agence Nationale de la Recherche (ANR)

Projet-ANR-20-CE91-0008