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ARS Home » Midwest Area » Urbana, Illinois » Global Change and Photosynthesis Research » Research » Publications at this Location » Publication #353540
Title: Tracing the fate of ozone in leaves

Author
item WEDOW, JESSICA - University Of Illinois
item EDER, ELIZABETH - Pacific Northwest National Laboratory
item WALTER, ERIC - Pacific Northwest National Laboratory
item HOYT, DAVID - Pacific Northwest National Laboratory
item Ainsworth, Elizabeth - Lisa

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/22/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Ozone is a greenhouse gas and considered the most damaging air pollutant to plants. Ozone enters leaves through the stomata, and once in the apoplast, it reacts to produce other reactive oxygen species (ROS) initiating a cellular response. The specific ROS initially formed after ozone exposure and the antioxidants involved in apoplastic detoxification vary among plant species, and even genotypes within a species. Very little is known about how maize responds to acute ozone exposure. To address this gap, maize was planted in growth chambers, under ambient air, and grown for 3 weeks with sufficient water and nutrients. After 3 weeks, plants were exposed to 200 ppb ozone and sampled after 0,1,5, and 24 hours of ozone exposure. Leaf material was taken for nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) from the youngest fully expanded leaf. A leaf section was cut and placed in a spin trapping solution and repeatedly vacuum infiltrated. Spin trapping allows for the transient and stable radicals to be detectable by EPR and NMR. EPR results showed the concentration of hydroxyl radicals in the leaves are higher under elevated ozone concentrations. Untargeted metabolomics was performed with 1H-NMR. Following initial exposure, ascorbate increased from 0 to 24 hours of exposure, while no effect on glutathione concentrations was observed. NAD+ was also significantly increased after ozone exposure. Future work will monitor in vivo measurements of ozone-induced ROS with EPR using an attached leaf within the measuring chamber of the instrument. This improved understanding of the nature and lifetime of ozone-induced ROS and antioxidant responses in maize will assist in modeling the fate of ozone and could help identify strategies for improving tolerance in C4 crops.