A new mechanism for tree mortality due to drought and heatwaves

Plants tend to die earlier in hot and drought conditions, but the underlying mechanisms are not yet understood.I propose here a new mechanism by which excessive residual water losses caused by high cuticular permeabilities and a high leaf-to-air vapor pressure deficits would trigger uncontrolled and sudden cavitation events.The combination of heat and drought stresses may therefore lead to an unsuspected risk of hydraulic failure.I explored this hypothesis with a new mechanistic model.The simulations support this hypothesis and highlight the critical role played by the cuticle phase transition temperature.Experiments are now awaited to confirm these predictions.