Plasticity in plant hydraulic traits: An evaluation of a common-taxa experiment across a climatic gradient in the Western U.S.

Drought impacts plant productivity, ecosystem function, and the global carbon cycle, with many species-level responses remaining unknown. Variable responses to water availability exist among plant species and across biomes. This research utilized a coordinated water deficit experiment of horticultural taxa across three sites in the Western U.S. to assess taxa-level plasticity to water availability and location. Four taxa (*Cercis occidentalis, Cercis canadensis, Physocarpus ‘*Diabolo’, and *Physocarpus ‘*Little Devil’) were measured for physiological and morphological traits affecting plant hydraulic conductivity under two water deficit treatments. Full gas exchange, specific leaf area, vessel diameter, theoretical hydraulic conductance, and ΦPSII were collected, and water use efficiencies calculated for each taxon at each location. Impacts of site, treatment, and taxa were analyzed on this suite of traits. Results show differences in taxa performance by climatic location (p < 0.001)..., Leaf physiology
End of season measurements of stomatal conductance to water vapor (gsw, mol m-2 s-1) and ΦPSII were taken with a LI-600 Porometer/Fluorometer (LI-COR Biosciences, Lincoln, NE, USA) during midday (11:30-1:30pm, to reduce risk of variable weather influence) at the three sites. The LI-600 configuration was set to automode with fast gs, fluorescence and flowrate, with matching to ambient conditions set to every 10 minutes. Midday instantaneous gas exchange survey measurements were taken with a portable photosynthesis system (LI-6400XT at OSU and LI6800 at UW and USU; LI-COR Biosciences, Lincoln, NE, USA) with a 2 cm2 chamber head and parameters set to 420 mmol mol -1 CO2; flow rate 500 mmol s-1, PAR at 2000 mmol m-2 s-1. Full gas exchange survey measurements were used to calculate instantaneous water use efficiency (WUE; mmol mol-1) as photosynthetic rate over transpiration rate (A/E) and intrinsic water use efficiency (iWUE; mmol mol-1) calculated as photosynthetic rate ove..., , # Data from: Plasticity in plant hydraulic traits: An evaluation of a common-taxa experiment across a climatic gradient in the Western U.S.

[https://doi.org/10.5061/dryad.sf7m0cggx](https://doi.org/10.5061/dryad.sf7m0cggx)

## Description of the data and file structure

Data (CRLP_2023_endcore.csv) includes physiological and morphological data collected at 3 sites in the Climate Ready Landscape Plants project in 2023: University of Washington (UW) Center for Urban Horticulture, Oregon State University (OSU) North Willamette Research and Extension Center and Utah State University (USU) Logan Research Farm. Four target taxa were selected, being grown at all 3 sites: *Cercis canadensis,* *Cercis occidentalis*, *Physocarpus*  'Little Devil' and *Physocarpus* 'Diabolo'. Replicates of each taxa were randomly assigned to receive an irrigation deficit treatment calculated as percent evapotranspiration with the high treatment (H) at 80% EtO and the low treatment (L) at 20% EtO. All data were co...,