The study looked at how long-term exposure to ozone affects the photosynthesis of winter wheat plants. They exposed the plants to different ozone levels and measured their chlorophyll fluorescence and gas exchange. The results showed that ozone stress led to a decrease in photosynthesis and damage to the plants' photosystems. The plants tried to protect themselves by adjusting their antioxidant system, but the excess ozone still caused significant harm. Overall, the study found that high ozone levels can significantly reduce the ability of winter wheat plants to photosynthesize, especially during certain growth stages.