DRIM: understanding the mechanism of drought-induced mortality in trees
Three different physiological mechanisms have been proposed to explain drought-induced mortality in trees: hydraulic failure (HFH), carbon starvation (CSH) and phloem impairment (PIH).
While there is convincing support for the HFH for some species, the support of the CSH remains tentative and the validity of this hypothesis has been recently put into question. The PIH is a new hypothesis we develop in this proposal.
Our main aim is to test these three different hypotheses and characterize the combinations of species and environmental conditions under which each of them is more likely to occur.
In order to achieve that we propose to combine three different approaches: observational studies and experimental manipulations in field populations currently suffering drought-induced mortality, detailed studies in the greenhouse under more controlled conditions, and a realistic modelling of phloem transport in trees incorporating xylem-phloem interactions.