Submitted to: Environmental Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2012
Publication Date: 4/20/2012
Citation: Burkey, K.O., Booker, F.L., Ainsworth, E.A., Nelson, R.L. 2012. Field assessment of a snap bean ozone bioindicator system under elevated ozone and carbon dioxide in a free air system. Environmental Pollution. 166:167-171.
Interpretive Summary: Ozone is an air pollutant that is toxic to plants, causing visible injury to foliage and a reduction in the growth and yield of many agronomic, horticultural and forest species. Ground level ozone is formed during reactions catalyzed by sunlight between oxygen in the air and volatile hydrocarbons and nitrogen oxides produced during fossil fuel combustion. Although frequently considered an urban problem, ozone is actually a regional problem because weather systems transport the pollutants into agricultural areas and forests. The impact of ozone for a specific location and growing season is difficult to assess due to the lack of an appropriate “clean air” reference. In this study, ozone sensitive (S156) and tolerant (R123) genotypes of snap bean that produce similar yields under “clean air” conditions were tested for development of a plant bioindicator system capable of detecting ozone effects at current levels of air pollution. Plants were exposed under field conditions to elevated levels of ozone, carbon dioxide, and the two gases in combination using Free Air Concentration Enrichment (FACE) technology at the SoyFACE site in Illinois. Elevated ozone reduced pod yield for S156 by 63%, but did not affect R123 yield. The S156/R123 yield ratio was identified as a potentially useful measurement to assess air pollution impacts on crops in a range of settings from highly managed experimental plots to agricultural fields.
Technical Abstract: Ozone-sensitive (S156) and -tolerant (R123 and R331) genotypes of snap bean (Phaseolus vulgaris L.) were tested as a plant bioindicator system for detecting O3 effects at current and future levels of tropospheric O3 and atmospheric CO2 under field conditions. Plants were exposed to reciprocal combinations of ambient and elevated levels of O3 and CO2 using Free Air Concentration Enrichment technology. Under seasonal ambient O3 concentrations marginal for injury, pod yields were not significantly different among genotypes. However, elevated O3 reduced pod yields for S156 (63%) and R331 (37%), but did not affect R123 yield. Complete amelioration of the O3 effect occurred in the O3+CO2 treatment. The S156/R123 yield ratio was identified as a useful measurement to assess O3 impacts with potential applications in diverse settings from highly managed experimental plots to agricultural fields.