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

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.