Hydraulic failure in Cerrado plants is reduced by plasticity in water loss, not water storage or embolism vulnerability

Increasingly frequent and intense drought events are challenging the survival of several forest species worldwide. Yet, the extent to which plants can postpone drought-induced mortality (DIM) through plastic adjustments in traits linked to hydraulic failure (HF) remains unclear. Here, we explored how the coordinated drought-induced plasticity in traits controlling water loss (WL), water storage capacity (WS), and drought tolerance (DT) influences the time to HF in a group of representative Cerrado species. Long-term exposure to drought induced marked morphoanatomical alterations in all the studied species, which minimized the impairments to their growth, while simultaneously reducing the risk of HF. However, those changes occurred almost exclusively in traits associated with the control of WL, both before and after complete stomatal closure, whereas traits related to WS and DT exhibited limited phenotypic plasticity. Despite this limited plasticity in hydraulic traits, all species showed inherently high hydraulic safety margins, achieved through a combination of early stomatal closure and high resistance to embolism, likely reflecting evolutionary pressures imposed by recurrent seasonal droughts in the Cerrado. Overall, our results highlight the necessity to embrace the complexity of drought acclimation mechanisms to improve the predictions of plant performance and survival under extreme weather events.