Antioxidant activity in mature branches of ponderosa pine (Pinus ponderosa) under long-term, low concentration ozone exposure
- Univ. of California, Davis (USA)
- Lawrence Livermore National Laboratory, CA (USA)
Antioxidant activity (superoxide dismutase, peroxidases and glutathione) is being examined in mature needle tissue of ponderosa pine exposed to elevated levels of ozone (O{sub 3}). Trees used in this study are 8-14 year-old clones produced from buds from a 70 year-old tree grafted onto seedling rootstock. Trees are exposed to O{sub 3} using a newly developed branch exposure chamber (BEC). Ozone treatments are charcoal-filtered, ambient and 2x ambient concentrations. A non-chambered branch will determine the effect of exposure chamber. Superoxide dismutase (SOD) activity measured in current-year needles in February via nitrobluetetrazolium (NBT) reduction was 138.5 {plus minus} 15 (SD) units mg{sup {minus}1} protein. The activity of guaiacol-oxidizing peroxidases was 89 {plus minus} 19 (SD) {Delta}A{sub 470} min{sup {minus}1} mg{sup {minus}1} protein. Ascorbate peroxidase and the ratio of oxidized to reduced glutathione (GSSG/GSH) are also being monitored. Antioxidant activity will be measured monthly across the ozone season (March to November) and during natural ozone episodes. Cellular antioxidant activity will be related to needle photosynthesis, respiration and stomatal conductance measured using a Licor 6200 portable photosynthesis apparatus.
- OSTI ID:
- 5628920
- Report Number(s):
- CONF-9007196--
- Journal Information:
- Plant Physiology, Supplement; (USA), Journal Name: Plant Physiology, Supplement; (USA) Vol. 93:1; ISSN PPYSA; ISSN 0079-2241
- Country of Publication:
- United States
- Language:
- English
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