High CO₂ effects on growth and biometal contents in the pioneer species Senna reticulata: climate change predictions

The aim of the present study consisted in evaluating the effects of CO₂ enrichment on the growth and biometal/nutrient content and accumulation in Senna reticulata germinated under two different carbon dioxide concentrations: atmospheric (360 mg L^-1) and elevated (720 mg L^-1). Biometal/nutrient determinations were performed on three different plant portions (leaflets, stem and root) using flame atomic absorption spectrometry. In general, the biometal and nutrient stoichiometries in roots were increased, probably due to reduced transpiration, and consequent biometal accumulation. An Artifical Neural Network analysis suggests that Mg, Na and Fe display the most different behavior when comparing plants germinated at atmospheric and elevated CO₂ conditions. Biomass and growth increases and certain elemental levels indicate that S. reticulata benefits from increased CO₂ levels, however some results indicate the contrary, making further studies in this context necessary, as these changes may lead to direct effects on food safety, crop yields, and phytoremediation efficiency.