How plants respond and adjust to rising Carbon dioxide (CO2) levels varies between species and genotypes. The most notable differences are found between C3 versus C4 plants; however, a mechanistic understanding of how these plant species respond to increased CO2 levels is missing. In this study, accessions of Brachypodiumdistachyon Bd21 (a C3 model grass) and Setaria viridis A10.1 (a C4 model grass) were grown under ambient and elevated CO2 levels and monitored non-invasively in a novel, image-based Dynamic Environmental Photosynthesis Imager (DEPI) chamber capable of revealing new transient or environment-specific phenotypes. Using the DEPI system, several chlorophyll fluorescence-derived photosynthetic parameters were imaged and analyzed. Our results revealed distinct alterations in photosynthesis-specific parameters, including quantum efficiency of PSII photochemistry (ΦII) and non-photochemical quenching (NPQ), as well as the rapidly relaxing (qE) and slowly relaxing (qI) components of NPQ during the plant life cycle. To further link the observed phenotypic traits at the organismal level to molecular phenotypes, the photosynthetic observations were complemented with gene expression, protein and metabolite profiling. Data analysis and integration from these experiments are in progress and will be presented and discussed. Our approach of integrating photosynthetic traits from nondestructive plant imaging over time with the internal phenotypes derived from omics profiles provides new opportunities to obtain detailed information on how plant traits respond to elevated environmental CO2 levels, knowledge which are of high agricultural relevance.
