Effects of elevated atmospheric CO₂ concentration and temperature on photosynthetic physiological mechanisms in C₃ crops

Climate change, characterized by elevated atmospheric CO₂ concentration and rising temperature, has become a globally focused issue that has significantly impacted crop production. Photosynthesis serves as the foundation of crop yield formation, while CO₂ is the substrate for photosynthesis. The increased atmospheric CO₂ concentration can promote the photosynthesis of C₃ crops, while increased air temperature generally constrains crop photosynthetic ability. However, the combined effects of elevated atmospheric CO₂ concentration and temperature on the crop photosynthetic mechanisms remain unclear. Focusing on the separate and interactive effects of elevated atmospheric CO₂ concentration and temperature, this review analyzes the changes of photosynthetic rate, chlorophyll content and stomatal conductance, as well as the phenomenon of "photosynthetic acclimation" in various crops, particularly C₃ crops. Considering regional differences in climate change, it explores the photosynthetic physiological mechanisms under concurrent elevated CO₂ concentration and temperature, with the aim of providing theoretical support for enhancing the photosynthetic capacity and ultimate productivity of C₃ crops under climate change conditions.