Experiment Title: “The cost of resource use for photosynthesis drives variation in leaf nitrogen content across a climate and resource availability gradient” Institutions responsible:

Texas Tech University
Experiment Description: The purpose of this experiment was to understand variance in leaf nitrogen content across a climate (largely precipitation) and resource availability gradient in Texas. Leaf samples were collected from 520 individuals spanning 57 species across 24 undisturbed sites and used to determine leaf nitrogen content and estimate the cost of acquiring nutrients relative to water (β) using leaf d13C. Leaf samples were collected during the summer months of 2020 and 2021.
Variables being tested: Experimental Details (factorial design, replication, lab/field/ controls, vegetation type): Data availability: Study limitations:
  • Leaf nitrogen per unit leaf area (Narea)
  • Leaf nitrogen per unit leaf biomass (Nmass)
  • Leaf dry biomass per unit leaf area (LMA/Marea)
  • Cost to acquire and use nitrogen relative to water (i.e. β, calculated from leaf d13C)
  • Leaf Ci:Ca, calculated through leaf d13C (i.e. χ)
  Environmental gradient study conducted in summer months of 2020 and 2021 along a 454-km longitudinal transect in Texas, United States. Sites were open savanna/grassland vegetation with leaf samples collected from mostly graminoids or annual forb/herbaceous species. Study contains 520 collected leaf samples across the gradient and have some diversity in photosynthetic pathway (C3, C4) and acquisition strategy (mainly AMF species, but some N-fixing species as well) Data are available on Zenodo: here

 

  Soil N availability is a one-time snapshot measurement and are included as site means. Soil moisture are not directly measured and were estimated using the SPLASH model using climate data downloaded from the PRISM climate dataset (daily 4-km gridded data product for coterminous United States)