Role of stomatal and leaf anatomical features in defining plant performance under elevated carbon dioxide and ozone,...

This research investigates the interactive effects of elevated ozone (eO₃) and carbon dioxide (eCO₂) on stomatal morphology and leaf anatomical characteristics in two wheat cultivars with varying O₃ sensitivities. Elevated O₃ increased stomatal density and conductance, causing oxidative stress and cellular damage, particularly in the O₃-sensitive cultivar PBW-550 (PW), compared to HUW-55 (HW). Conversely, eCO₂ reduced stomatal density and pore size, mitigating O₃-induced damage by limiting O₃ influx. Ultrastructural analysis showed that eO₃ increased plastoglobule density and damaged chloroplast structure, while eCO₂ preserved chloroplast integrity and enhanced photosynthetic efficiency. Additionally, eCO₂ increased leaf thickness and improved mesophyll conductance, counteracting the negative effects of O₃ on leaf anatomy. The CO₂-induced modifications in stomatal and leaf anatomy significantly impacted plant physiology by altering stomatal conductance and O₃ uptake. The protective effect of eCO₂ was more pronounced in the O₃-sensitive cultivar PW than in the O₃-tolerant HW. These findings provide insights into the stomatal and leaf anatomical responses of plants under future climate conditions, aiding in the developing strategies to improve crop resilience and productivity under O₃ stress.