Leaf economics spectrum of wheat in response to multigenerational atmospheric elevated CO2

While numerous studies have explored the impacts of elevated atmospheric CO₂ concentration (e[CO₂]) on leaf traits in plants within a single life cycle, the effects of multigenerational e[CO₂] on leaf functional traits and their interrelationships remain obscure in major crops. Leaf economics spectrum (LES) comprises a group of leaf traits, which describes trade-offs between the leaf characteristics that reflect carbon economy or returns on the investments of nutrients and dry mass. In this study, the wheat seeds harvested from a 7-generation experiment under the e[CO₂] (800 μmol L⁻¹) or the ambient CO₂ concentration were planted to assess changes in the LES. Our results revealed a consistent increase in mass-normalized leaf nitrogen and phosphorus concentration under the e[CO₂] over the generations. Photosynthetic phosphorus use efficiency was positively correlated with photosynthetic rate per unit mass, dark respiration per unit mass, photosynthetic rate per unit area, leaf phosphorus per unit area, and dark respiration per unit area. Moreover, we used structural equation model to illustrate the network of relationships among LES traits and shoot dry weight, providing insights into the effects of the multigenerational e[CO₂] on wheat growth. This study contributes novel perspectives to our understandings of wheat responses to long-term climate change.