co2-response
CO2 response refers to the physiological and molecular mechanisms by which plants detect and react to changes in atmospheric carbon dioxide concentrations. As CO2 is a primary substrate for photosynthesis, plants have evolved complex signaling pathways that regulate stomatal aperture, carbon fixation rates, and gene expression in response to CO2 fluctuations. Understanding these responses is critical for predicting how plants will adapt to rising atmospheric CO2 levels and for engineering crops with improved photosynthetic efficiency and water-use efficiency.
open_in_new WikipediaPubMed · 2026-01-01
Plants universally reduce the number of leaf pores (stomata) as CO₂ levels rise, regardless of whether they evolved in high or low CO₂ environments. However, local stressors like heat and low humidity can override this pattern, complicating predictions about how vegetation will respond to a CO₂-rich future.
Stomatal frequency decreased with rising CO₂ (30 vs. 42 Pa) in all tested C₃ plants, regardless of their CO₂ acclimation history
Plants grown at reduced CO₂ (~30 Pa) developed smaller stomatal apertures than those at ambient CO₂ (~40 Pa), and also produced less above-ground biomass
No significant difference in stomatal frequency was found between plants naturally acclimated at 2,970 m altitude versus 540 m, suggesting local environmental factors (temperature, humidity) can mask the CO₂ signal