Comparative Apparent Hydraulic Conductance, Leaf Gas Exchange, and Water Resource Partitioning of Populus euphratica Trees and Saplings

Water acquisition via the root system of woody species is a key factor governing plant physiology. In order to compare impact water on hydraulic and photosynthetic characteristics different-sized Populus euphratic, which desert riparian tree species, we quantified leaf conductance (KL), stomatal (gs), net rate (PN), predawn midday potential (Ψ), stem δ18O saplings mature trees. The results showed that had lower (Ψpd) soil-to-leaf gradient (ΔΨ) higher KL than trees but similar gs PN arid zones, probably due limitation, were more likely use unreliable topsoil (<80 cm), whereas typically uptake reliable deep soil (>80 cm) groundwater having deeper systems. unreliability supply might make hold ensure transported efficiently leaves satisfy their transpiration need. contrast, trees, resources, relatively low leaf-specific because increased path length versus saplings. However, adult can maintain by upregulating ΔΨ, thereby facilitating ability carbon assimilation This regulating behavior benefits trees’ gain, it comes at expense an risk failure. These imply top priority for should be functioning, whereas, assure stable gain growth.