No Detectable Maternal Effects of Elevated CO2 on Arabidopsis thaliana Over 15 Generations

Maternal environment has been demonstrated to produce considerable impact on offspring growth. However, few studies have been carried out to investigate multi-generational maternal effects of elevated CO₂ on plant growth and development. Here we present the first report on the responses of plant reproductive, photosynthetic, and cellular characteristics to elevated CO₂ over 15 generations using Arabidopsis thaliana as a model system. We found that within an individual generation, elevated CO₂ significantly advanced plant flowering, increased photosynthetic rate, increased the size and number of starch grains per chloroplast, reduced stomatal density, stomatal conductance, and transpiration rate, and resulted in a higher reproductive mass. Elevated CO₂ did not significantly influence silique length and number of seeds per silique. Across 15 generations grown at elevated CO₂ concentrations, however, there were no significant differences in these traits. In addition, a reciprocal sowing experiment demonstrated that elevated CO₂ did not produce detectable maternal effects on the offspring after fifteen generations. Taken together, these results suggested that the maternal effects of elevated CO₂ failed to extend to the offspring due to the potential lack of genetic variation for CO₂ responsiveness, and future plants may not evolve specific adaptations to elevated CO₂ concentrations.