KIT-Campus Alpin

1 INTRODUCTION Water-use efficiency (WUE) reflects the balance between carbon gain and water loss in plants (Leakey et al. 2019; Brendel et al. 2021; Vadez et al. 2023). Intrinsic water-use efficiency (iWUE) indicates a momentary balance of leaf carbon and water fluxes and corresponds to the ratio of net CO2 assimilation rate (An) to stomatal conductance to water vapour (gs) (Roussel et al. 2009; Petek-Petrik et al. 2023).

Drought stress challenges tree function and survival. The degree of such challenges depends on tree life traits (LTs), spanning from hydraulic structure to management of carbohydrate reserves, to structural adjustments. In their work, Ziegler et al. (2024) combine observations with modelling to investigate the relevance of several LTs during dehydration in 12 rainforest tree species.

1 INTRODUCTION Xylem embolism is a process in which air bubbles block the water-conducting elements of a plant. This happens when the tension in the functional xylem conduits becomes extreme, either due to a decrease in soil water availability or increased atmospheric demand (i.e., vapor pressure deficit; VPD).