Location: Plant Science ResearchTitle: Application and further characterization of the snap bean S156/R123 ozone biomonitoring system in relation to ambient air temperature
|AGATHOKLEOUS, EVGENIOS - Hokkaido University|
|SAITANIS, COSTAS - Agricultural University Of Athens|
|NTATSI, GEORGIA - Agricultural University Of Athens|
|VOUGELEKA, VASILIKI - Agricultural University Of Athens|
|MASHAHEET, AL-SAYED - North Carolina State University|
|PALLIDES, ANDREAS - Agricultural Research Institute Of Cyprus|
Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2016
Publication Date: 2/15/2017
Citation: Agathokleous, E., Saitanis, C., Burkey, K.O., Ntatsi, G., Vougeleka, V., Mashaheet, A., Pallides, A. 2017. Application and further characterization of the snap bean S156/R123 ozone biomonitoring system in relation to ambient air temperature. Science of the Total Environment. 580:1046-1055.
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 agricultural, forestry and native 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. Plants exhibiting differences in ozone sensitivity are being developed as bio-indicators to assess local ambient ozone impacts on vegetation. In this study, ozone sensitive (S156) and tolerant (R123) genotypes of snap bean originally developed by USDA-ARS scientists in Raleigh, NC were further characterized as an ozone bio-indicator system. A team of researchers from Greece, Japan, Cyprus, and USDA-ARS conducted field trials in Athens, Greece and complementary controlled environment studies in the United States that showed the snap bean system to be a useful tool to assess ozone impacts on vegetation. The S156/R123 pod yield ratio was identified as a useful measurement to assess air pollution impacts except in environments where high temperature limits pod formation. For high temperature situations, differences in ozone-induced foliar injury between S156 and R123 provide an alternative approach to assess air pollution effects in settings ranging from highly managed experimental plots to agricultural fields.
Technical Abstract: Increased mixing ratios of ground-level ozone threaten individual plants, plant communities and ecosystems. In this sense, ozone biomonitoring is of great interest. The ozone-sensitive S156 and the ozone-tolerant R123 genotypes of snap bean (Phaseolus vulgaris L.) have been proposed as a potential tool for active biomonitoring of ambient ozone. In the present study, we conducted ozone biomonitoring, with the S156/R123 tool, along with a monitoring of ozone and other environmental conditions in an urban area, in Athens, Greece, during the growing seasons of 2012 and 2013. Plant yield was evaluated to assess the effectiveness of AOT40 in interpreting ozone-induced phytotoxicity. Across the two genotypes, we found an approximately two times lower total number of pods –and consequently lower bulk mass of seeds– in 2012 than in 2013, although there was no significant difference in the final AOT40 between the two years. No significant differences were observed in stomatal density or in stomatal conductance between the two genotypes. However, it was estimated that the abaxial surface contributes 2.7 fold to ozone intake in comparison to the abaxial one. By testing the role of ambient air temperature in outdoor plant environment chambers (OPECs), we found that temperature limits mature pod formation and complicates interpretation of ozone impacts in terms of S156/R123 yields ratios and AOT40 in interpreting O3-induced phytotoxicity. This is the first study providing evidence for a hormetic effect of ambient air temperature on plants. This study also points out the complexity of using yield as a measure of ozone impact across different environments with the snap bean system, whereas visible foliar injury is more consistently related to ozone alone.