Growth and metabolic responses to the transgenerational exposure to elevated [CO2] in wheat.

Climate change poses a major threat to global crop production, with rising atmospheric carbon dioxide concentrations ([CO2]) expected to directly influence plant growth, physiology, and phenology. While these effects are commonly studied in single-generation experiments, these studies do not address the potential for transgenerational responses, where the environmental conditions experienced by parent plants shape the performance of their offspring. To shed light on this aspect, we cultivated wheat under ambient and elevated [CO2] over two generations, with seeds harvested in the first year planted in both growing environments the second year. As expected, within an individual generation, plants exposed to elevated [CO2] showed increased total biomass and carbon allocation and a slight reduction in nitrogen concentration (∼9%). However, the second generation differently responded to elevated [CO2]. Although elevated [CO2] over two generations still enhanced plant growth, some sugars and organic acids decreased, together with a strong reduction in nitrogen concentration (∼58%) and most amino acids, associated with an imbalance of plant energy status. Our results uncover a transgenerational effect of elevated [CO2] that dampens the metabolic flexibility of wheat plants under continued CO2 enrichment. This finding underscores the lasting influence of the maternal environment and emphasizes its pivotal role in shaping plant responses to future climate scenarios.