INTERACTIVE EFFECTS OF ELEVATED CO2 AND SALINITY ON THREE

Abstract

Atmospheric carbon dioxide (CO2) has increased steadily since Pre-Industrial times. The need for a better understanding of the effects of ele-vated CO2 on plant physiology is clear, particularly in the context of other changes and stresses. Previous studies have focused on how plants are af-fected by either elevated CO2 or salinity, one of many plant stresses. How-ever, little is known about the interaction of these two factors on plant growth. In my project, plants were exposed to both elevated CO2 and salini-ty, so that the effects of either factor and the interaction of the two on common grass species could be examined. Three grass species were sub-jects for my experiment. Kentucky bluegrass (Poa pratensis L.) and red fes-cue (Festuca rubra L.), both C3 cool season grasses, as well as buffalo grass(Buchloe dactyloides (Nutt.)Engelm.), a C4 warm season grass, were studied. The CO2 levels were set to 400 μmol mol-1, close to the current concentration, or 760 μmol mol-1, projected to be reached by the end of this century. The salt concentrations were 0, 25, 50, 75, and 100 mM NaCl with CaCl2 added at lower rates (1% of each respective molarity for NaCl). Five replicates per treatment (a total of 150 pots) were grown for 100 days. My results demonstrated stimulated growth at elevated CO2 and inhibited growth with increasing salinity. Collection and statistical analysis of data for variance is being performed to determine which, if any, of the fixed factors had significant effects on the given parameters. My results will improve the understanding of plant responses to multiple environmental changes in the future.