Leaf habit determines the hydraulic and resource-use strategies in tree saplings from the Sonoran Desert.

This article investigates how saplings of seven Sonoran Desert tree species with different leaf habits (LH)—deciduous versus evergreen—differ in morphological and physiological responses to drought. The study found that deciduous saplings exhibit isohydric behavior characterized by tighter stomatal control, higher maximum stomatal conductance and CO₂ assimilation rates, faster growth, and traits associated with rapid resource use under well-watered conditions, but they strongly reduce gas exchange under drought. In contrast, evergreen saplings display anisohydric behavior with lower and more constant stomatal conductance and assimilation rates regardless of water availability, coupled with traits indicating slower resource use and greater drought resistance. These contrasting strategies align with the iso-anisohydric continuum and the fast–slow plant economics spectrum, reflecting adaptations to the highly seasonal and arid environment of the Sonoran Desert.