Ethylenediurea (EDU) mediated protection from ambient ozone-induced oxidative stress in wheat (Triticum aestivum L.) under a high CO2 environment

Abstract

A FACE (Free Air Concentration Enrichment) study was conducted with ethylenediurea (EDU; 200 ppm) on two wheat cultivars (PBW-154, WH-1105) in high ambient ozone (AO3) stress under ambient CO2 (ACO2) and elevated CO2 (ECO2; 550 ppm). During the study period, AO3, ACO2, and ECO2 concentrations were 63 ppb, 413.69 ppm, and 553.54 ppm, respectively. Mean O3 and AOT40 concentrations were high enough to induce oxidative stress in plants. EDU treatment enhanced wheat biomass and yield under ECO2. Under ECO2, EDU-treated PBW-154 and WH-1105 showed increased photosynthesis, chlorophyll content, grain weight plant−1, grain no plant−1, and 1000 grain weight, compared to EDU-treated cultivars grown under ACO2. EDU-treated wheat showed less lipid peroxidation, high levels of antioxidants and antioxidant enzymes under ambient and ECO2 conditons. EDU significantly increased biomass (at flowering phase), antioxidant activities (at both vegetative and flowering phases), and yield in WH-1105 cultivar in comparison to EDU-treated PBW-154 under ACO2. WH-1105 cultivar was found to be more sensitive to O3. Improved growth, grain yield, and grain nutrient attributes of wheat with EDU under ECO2 environment showed that prevailing ambient O3 levels are already causing yield losses and will continue to do so in future high CO2 environment also. ECO2 negatively impacted grain nutrients in both wheat cultivars. EDU mitigated the deleterious impact of high ambient ozone-induced oxidative stress in the wheat crop grown in ECO2 environment. Further, EDU also alleviated both the negative impacts of high ambient O3 stress on grains and ECO2-caused decline in grain nutrient content in wheat.