• Triticum (wheat);
  • ozone;
  • drought stress;
  • oxidant stress biomarkers;
  • open-top chambers


Protein content, catalase activity (CAT), non-specific peroxidase activity (POD), ascorbic acid content (AsA) and malondialdehyde content (MDA) were estimated in flag leaves of spring wheat exposed to ozone and drought stress in open-top chambers. Four harvests were carried out at different developmental stages to estimate the time course of these parameters. Senescence was enhanced by ozone which was reflected in the time course of the oxidant stress biomarkers. Protein content decreased, and POD and MDA increased only after the leaves had experienced high doses of ozone, whereas AsA levels were raised in ozone-treated plants after only a short exposure period. CAT did not significantly respond to ozone treatment, but, ozone accelerated the progress of its time course. Drought stress did not influence the time course of any of the estimated parameters, but led to somewhat increased levels of AsA.