Experiment Title: Leaf photosynthetic and morphological adaptations to rising CO2 levels and elevation. Institutions responsible:

Utrecht University (Astrid Ode)
Experiment Description: The aim of this experiment is to gain insight in the adaptation of leaf gas exchange- and photosynthesis traits to rising CO2 levels and elevation. Herbarium material of four species was selected over an elevational (~0 – 3500 meters) and time (~1900 – 2010) range in California, which will reflect changes in temperature, partial pressure of CO2/O2 and atmospheric CO2 concentration.  Measurements include analysis of stable carbon isotopes (to infer χ) , C:N content, LMA, and stomatal size and -density.
Variables being tested: Experimental Details (factorial design, replication, lab/field/ controls, vegetation type): Data availability: Study limitations:
  • leaf δ13Cand leaf Ci:Ca (χ)
  • leaf nitrogen and carbon content
  • stomatal density and morphology (gsmax)
  • vein density?
  • LMA
  • Needle length for the conifer species
 Samples originate from the UCU Berkeley and Jepson herbarium.  Species consist of 2 conifer (Pinus longaeva, Pinus ponderosa) and 2 broadleaf (Quercus agrifolia, Quercus chrysolepis) species originating from California. Each species has a timerange ~1900-2010, and two subsets: high and low elevation range.

Lab protocol trials were done on small sample sets.

Data of lab trials are available on a Github repository. Use of trial data on request, not yet published.

Data analysis ongoing.

 Other influences on the stable carbon isotope ratio besides Ca, mainly drought (microclimates) influences the results. Conservation status of the samples may limit microscopy results. Limited sample size because of herbarium material.