Variation in salinity tolerance and water use strategies in an introduced woody halophyte ( <i>Tamarix</i> spp.)

The form and function of terrestrial plants is largely governed by the availability water, with in water-limited environments expressing traits minimizing water loss tissue damage during drought. Areas high salinity are analogous to those low availability, even where abundant. We evaluated variation tolerance use strategies an introduced halophytic shrub, Tamarix spp measuring gas exchange rates, biomass accumulation turgor points. hypothesized that not uniformly expressed, ecotypes more conservative maximize hydraulic safety over conductance rates. studied two populations spp. along lower Colorado River, groundwater differed nearly sixfold. Cuttings collected from sites were grown a greenhouse five levels 0 32 parts per thousand (ppt), imposing increasing limitation. In situ measurements leaf potentials (Ψ) branch xylem anatomy taken on sourced high- low-salinity sites. greenhouse, rates 0–32 ppt gradient, separate dry down experiment was performed determine points stomatal responses drying soils. population accumulated 72% when at 4 compared 16 ppt, while produced 50% ppt. Net carbon assimilation greater salinities but independent population. had point exhibited control relative Synthesis. Results provide evidence for divergence related plant across gradients this recently halophyte. Local adaptation increased has implications aridland riparian ecosystems, management or drought may lead altered soil salinities. interaction trait within likely favour its continued dominance.