BRENDEL Oliver Research Unit: SILVA Research Team: PHARE ‘Physiology of the tree in its environment’ Centre INRAE Grand Est -Nancy F-54280 CHAMPENOUX (France) oliver.brendel@inrae.fr +33 (0) 3 83 39 41 00

Field of expertise: 

The combination of forest tree ecophysiology and intra-specific diversity

Main areas of interest:

My main area of interest is the genetic diversity of traits that are related in forest trees to the carbon / water balance in general and to the responses to soil water deficit more specifically. I used also to work on the other extreme soil water condition : water logging and the resulting root hypoxic conditions, however this subject has been slowing down lately.

I'm interested in characterising intra-species diversity in forest trees and the geographical structure of such a diversity, where geographical structure ranges from differences among provenances to micro-scale variation of trees and seedlings that grow a few meters to a km apart.

I focussed in the past on leaf level traits relating to water use efficiency, the ratio between biomass accumulation and transpired water. Thus recent studies (e.g. Vialet-Chabrand et al 2013) have for example explored the diversity of temporal responses of stomata to irradiance and how this effects daily time-courses of water-use efficiency. More recent and future research now investigates how these daily time courses relate to whole plant water use efficiency.

As screening of diversity is much easier using genes that have an adaptive impact, some of my research in collaboration with geneticist colleagues aims to determine such genes for water use efficiency. Some recent advances of QTL detection for water use efficiency and related traits in different forest tree species (e.g. maritime Pine Marguerit et al 2014, Eucalyptus Bartholomé et al 2015), especially in combination with available genome sequences, have resulted in list of genes or at least functions (gene ontology).

The screening of ecophysiological traits on a large number of individuals is complicated by the rapid (minutes to hours) responses of many of these traits to slight environmental changes (temperature, irradiance, vapour pressure deficit). The estimation of water use efficiency is facilitated by the Farquhar model, which is relating it to variation in carbon isotope discrimination between atmospheric CO2 and carbon in the plants. The plant carbon isotope composition can therefore be used as an estimator of leaf level water use efficiency. It can be measured on different organic material such as leaves and wood, where tree rings constitute a temporal archive of water use efficiency. Carbon isotope composition of wood can therefore not only be used to screen a large number of individuals, but also to study the diversity of plasticity to past environmental changes. I have therefore developed some competences in the use of carbon isotopes to estimate water use efficiency.

Most of these scientific subjects have recently been put together in a scientific five-year project on diversity of water use efficiency in pedonculate and sessile oak : H2Oak.

Keywords

• water use efficiency
• local adaptation of populations
• dynamic responses of stomata to rapid environmental variations
• drought responses of trees

Publications from HAL: https://cv.archives-ouvertes.fr/oliver-brendel