SurEau: a mechanistic model of plant water relations under extreme drought

Abstract Key message A new process-based model, SurEau , is described. It predicts the risk of xylem hydraulic failure under drought. Context The increase in drought intensity due to climate change will accentuate tree mortality. But very few models are currently able predict this mortality risk. Aims We describe operating principle a mechanistic model that computes water balance, relations, and hydraulics plant extreme Methods based on formalization key physiological processes response stress. hydric functioning at core which focuses both flows (i.e., hydraulic) pools hydric) using variable conductances. considers elementary flow from soil atmosphere through different organs described by their symplasmic apoplasmic compartments. For each organ, symplasm pressure-volume curve apoplasm its vulnerability cavitation. evaluated mature oak trees exposed Results On tested trees, captures well observed level embolism. sensitivity analysis reveals embolism strongly determined air VPD traits such as cuticular transpiration, resistance cavitation, leaf area. Conclusion offers opportunities evaluate how species or genotypes respond future climatic conditions.