ROS production and its detoxification in early and late sown cultivars of wheat under future O3 concentration

• Published in: The Science of the total environment Vol. 659; pp. 200 - 210
• Main Authors: Yadav, Durgesh Singh, Rai, Richa, Mishra, Amit Kumar, Chaudhary, Nivedita, Mukherjee, Arideep, Agrawal, S.B., Agrawal, Madhoolika
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2019
• Subjects: Enzymatic antioxidants; Non-enzymatic antioxidants; Ozone; ROS; Stomatal flux; Wheat cultivars; Ozone; Enzymatic antioxidants; Stomatal flux; ROS; Non-enzymatic antioxidants; Wheat cultivars
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.12.352

The present field study was planned with an objective to unravel the mechanisms behind the differential responses of early and late sown wheat cultivars with respect to their defense capacity to scavenge ROS induced under elevated O3 (EO3). Experiments were performed under ambient and elevated levels of O3 (ambient + 20 ppb) to plants inside open-top chambers (OTCs). Ozone concentrations, stomatal flux of O3 and meteorological parameters were measured throughout the experiment. Contents of superoxide radicals (O2−) and hydrogen peroxide (H2O2) and their localization, lipid peroxidation, antioxidative enzyme activities, ascorbic acid and total phenolic contents were measured at vegetative and reproductive developmental stages. EO3 exposure induced higher stomatal flux of O3 in early sown cultivars. Higher contents of O2−, H2O2 and lipid peroxidation were noticed under EO3 in all the cultivars but the magnitude of increases was higher in late sown cultivars at the reproductive stage. Activities of glutathione reductase (GR) and ascorbate peroxidase (APX) were higher in late sown cultivars under EO3. Ascorbic acid and total phenolic contents were significantly higher in early sown than late sown cultivars under EO3 treatment. The present study concludes that early sown cultivars are more efficient in their defense response due to higher induction of enzymatic and non-enzymatic antioxidants, while the induction of enzymatic antioxidants was more distinct in late sown cultivars. Non-enzymatic linked defense mechanism requires additional metabolic cost than enzymatic defense, making early sown cultivars more susceptible to EO3. Differential response of early and late sown cultivars with respect to antioxidative defense against O3 stress suggests that yield responses are governed by the time of sowing and intrinsic defense responses of the cultivars. In future with rising trend of O3, early sown cultivars are expected to be more vulnerable to oxidative stress compared to late sown cultivars. [Display omitted] •Early and late sown wheat cultivars were tested for sensitivity under elevated O3.•Stomatal flux of ozone was higher in early sown cultivars compared to late sown.•Non enzymatic antioxidants induced more in early sown cultivars under elevated O3.•In late sown cultivars enzymatic antioxidants induced more under elevated O3.•Sowing time and intrinsic defense response optimized yield in different cultivars.