Stable carbon isotope and biomass values of plants grown under different levels of soil moisture and atmospheric CO₂

Stable carbon isotope and biomass measurements of Arabidopsis thaliana grown in controlled growth chambers within laboratory conditions under varying soil moisture (theta) and atmospheric CO2 level. Measurements of above-ground plant tissues were made just prior to flowering (27-30 days after seed sowing). The purpose of this study was to investigate the effects of soil moisture and CO₂ level on plant carbon isotope value and biomass. The above-ground tissues from each plant were harvested and dried at 60 °C, then weighed to assess the biomass of each plant (± 0.1 mg). The stable carbon isotope values for each plant were then analyzed using a Delta V Advantage Isotope Ratio Mass Spectrometer (Thermo Fisher, Bremen, Germany) coupled to a Costech ECS 4010 Elemental Analyzer with a zero-blank autosampler (Costech Analytical, Valencia, CA, USA). Data were normalized to the Vienna Pee Dee Belemnite (VPDB) scale using internal lab reference materials (JGLUT: δ13C = -13.43‰; JGLY: δ13C = -43.51‰). In order to assess the accuracy and precision of the analyses, six capsules of quality-assurance standards (JRICE) were analyzed as unknowns with each batch run. Across all analyses, the JRICE quality assurance sample averaged δ13C = -27.37 ± 0.05‰ (n = 60), which is in agreement with the calibrated value of -27.37‰.