Brief Summary of Minutes of Annual Meeting

The meeting was called to order at 9:00 a.m. on Monday, May 21, 2007 by Fitz Booker, Chair of the Technical Committee, who introduced committee members and presented the history, objectives and collaborative projects of NE-1013. Ray Knighton informed the group that the renewal project NE-1030 had been approved for a new 5-year period through September 30, 2012, and presented a number of federal budgetary items and funding opportunities that are pertinent to research and outreach activities of the Technical Committee. Stations reports were then presented. R. Muntifering (AL) reported that a long-term experiment in a sub-alpine pasture in Switzerland found that with high N input, nutritive quality was 7% lower for elevated O3 treatments, likely due to cell-wall compositional changes. D. Decoteau (PA) reported that development continues on teaching and outreach materials for use by public-school teachers and at the Air Quality Learning and Demonstration Center. M. McGrath (NY) showed that ambient O3 caused severe injury to leaves and defoliation in an ozone-sensitive snap bean cultivar, S156. H. Neufeld (NC) reported that there were no statistically significant short-term O3 effects in leaves of tulip poplar although foliar injury has been observed in the field. Multiple O3-exposure episodes may be required before measurable responses in this species can be detected. N. Grulke (CA) described a new-gas exchange system that directly measures O3 flux into a leaf. D. Grantz (CA) reported that exposure of Pima cotton to O3 led to genotoxic impacts on root tips while application of methyl jasmonate caused a suite of developmental changes reminiscent of O3 exposure. In addition, glyphosate-resistant horseweed was less susceptible to being driven out of the population by the combination of high O3 and glyphosate. F. Booker (NC) showed that elevated CO2 ameliorated O3 effects on soybean yield while treatment effects on biomass production dominated potential impacts on soil C dynamics. L. Ainsworth (IL) reported that tests at SoyFACE of soybean cultivars that have been released over a 50-year period found no relationship between O3 tolerance and year of release. K. Burkey (NC) reported that screening of 30 soybean ancestors for O3-induced foliar injury was not always a good predictor of yield loss in open-top chambers. Cosima Wiese (PA) discussed the role of the leaf apoplast in plant defense responses to oxidative stress. Barbara Zilinskas (NJ) reported that yield reduction due to ambient O3 in the O3-sensitive S156 snapbean line was close to 50% in dry weight of pods and seeds. Barbaras group is also investigating the role of glutathione peroxidase in O3 signal transduction pathways. Heinrich Sandermann (Germany) summarized present knowledge on the mechanisms of O3 phytotoxicity. Tuesday, May 22: Dave Karnosky (MI), local host for the meeting and director of the Aspen FACE project, gave an overview of the Aspen FACE research, which is testing how O3 alters the response of northern forest ecosystems to elevated CO2. John King (NC) reported that northern forests have the capacity for sustained growth stimulation due to elevated CO2, and that concurrent exposure to moderate levels of tropospheric O3 partially or totally compromises growth stimulation from elevated CO2. Mark Kubiske (WI) showed that inter-annual variation in relative aspen growth responses to elevated CO2 and O3 at AspenFACE was highly correlated with average daily solar radiation in July and temperature in October. Rainer Mayssek (Germany) described a free-air O3 fumigation experiment with 60-year-old Norway spruce and European beech at Kranzberg Forest. Ozone induced leaf injury in beech, enhanced soil respiration and fine-root production and turnover, but did not cause consistent damage patterns in beech and spruce foliage across years. Kevin Percy (Canada) showed that elevated CO2 and O3 continue to affect in opposite ways leaf surface characteristics in the five aspen clones at AspenFACE. Leaves expanded under O3 had significantly lower leaf miner egg densities, which was partly attributable to effects on epicuticular wax. John Carlson (PA) presented an overview of research in the Schatz Center for Tree Molecular Genetics at Penn State, which he directs, and described a study using hybrid poplar and black cherry genotypes that differ in O3 sensitivity to determine the role of gene expression in O3 sensitivity. Percy et al. also used data from Aspen FACE to develop exposure-based metrics for prediction of O3 damage to aspen. Regression techniques using five years of O3, meteorology and growth data showed that the current EPA primary NAAQS should be considered in a slightly altered form (growing season) as a candidate for a new Secondary standard to protect vegetation. The group adjourned and toured the Aspen FACE site for the remainder of the day. The following items were addressed during the business meeting: 1. NE-1030 was officially approved on 5/14/07. 2. David Grantz, Chair-Elect, will take over the position of Chair after next years 2008 meeting and will preside over the 2009 and 2010 meetings. A new Chair-Elect will be elected at the 2008 meeting. 3. The US Forest Service has created the Paul Miller Clean Air Award, a national award for Forest Service employees to honor his memory. US Forest Service members on the Technical Committee were encouraged to consider nominating deserving USFS individuals for this recognition. 4. The NE-1013 termination report is due March 31, 2008. Station termination reports should be sent to Fitz by February 15, 2008. The following people agreed to help compile the final report: Objective 1  M. McGrath, D. Decoteau Objective 2  R. Muntifering, H. Neufeld Objective 3  F. Booker, D. Grantz Objective 4  B. Zilinskas, K. Burkey Objective 5  S. Krupa 5. K. Burkey provided an update on the snap bean project status. MN, NJ, NC, PA, and NY will continue this research in 2007. 7. M. McGrath was elected Secretary for the 2008 meeting. 8. Next years meeting of the new NE-1030 project will be held at Auburn University, hosted by A. Chappelka and R. Muntifering.

Objective 1. Describe the spatial  temporal variability of the adverse effects of O3 on crops and forests 1. Ambient O3 caused severe injury to leaves and defoliation in the O3-sensitive snap bean cultivar, S156. Total weight of bean pods harvested for fresh-market consumption was 40 to 50% lower for S156 compared with the tolerant genotype (R331) (NY, NC, PA, NJ, MD). 2. Testing at SoyFACE of soybean cultivars released over a 50-year period found no relationship between O3 tolerance and year of release. Some of the newest cultivars were found to be as sensitive to O3 as other cultivars released 50 years ago. (IL). 3. A potential bio-energy crop, sugarcane, was found to be moderately sensitive to O3. This suggests a further challenge, in addition to chilling and salinity stresses, in introducing these tropical crops into the arid western valleys. It also indicates that conventional wisdom regarding inherent O3 resistance among C4 species may need reexamination. In this case sensitivity was similar to that observed in moderately O3-sensitive cultivars of commercial cotton. (CA). Objective 2. Assess the effects of O3 on structure, function and diversity of plant communities 1. Results from a five-year experiment with Swiss collaborators in a species-rich, sub-alpine pasture exposed to three concentrations of O3 and five levels of N deposition showed that with high N input, nutritive quality was 7% lower for elevated O3 treatments. Cell-wall compositional changes are likely involved in this response. In addition, altered nutritive quality was associated with shifts in proportions of plant functional groups (grasses, forbs and legumes) due to O3. During the experiment, forbs increased from 23 to 36%, grasses decreased from 68 to 60%, and legumes decreased from 9 to 3% of biomass harvested from the O3-enriched plots. Decreased forage nutritive quality often leads to lower milk and meat production, thus linking air quality with impacts on animal production systems. (AL). 2. In controlled environment experiments, there were no statistically significant short-term O3 effects in leaves of tulip poplar although foliar injury has been observed in the field. Multiple O3 episodes during a growing season are probably necessary before measurable responses in this species can be detected. (NC). Objective 3. Examine the joint effects of O3 with other growth regulating factors on crop and tree growth and productivity. 1. Glyphosate-resistant horseweed, which has almost completely replaced the susceptible biotype in the San Joaquin Valley, was found to be less likely than the susceptible genotype to being driven out of the population by the combination of high O3 and application of glyphosate. Ozone pollution may thus contribute to crop production costs due to a need for increased weed control practices as well as by curtailing yield. (CA). 2. An experiment designed to test the effects of elevated CO2 and O3 on soil carbon and nitrogen dynamics in a soybean-wheat no-till system using open-top chambers showed that elevated CO2 (550 ppm) increased soybean and wheat yield by 10 to 25% while O3 (1.4 × ambient, 68 ppb) suppressed soybean yield by 11 to 27%. In combination, elevated CO2 ameliorated O3 effects on soybean yield. Treatment effects on biomass production dominated potential impacts on soil C dynamics as evidenced by litter levels in the treatment plots and minirhizotron images of root production. (NC). 3. The AspenFACE experiment indicated that northern forests have the capacity for sustained growth stimulation due to elevated CO2, and that concurrent exposure to moderate levels of tropospheric O3 partially or totally compromises growth stimulation from elevated CO2. Also, elevated CO2 and O3 have small effects on litter chemistry and specific rates of decomposition, while changes in litter inputs under elevated CO2 and O3 will likely have large effects on soil organic matter. (NC). Objective 4. Examine the molecular and physiological basis of O3 toxicity and tolerance in plants 1. Application of methyl jasmonate, a phytohormone, to Pima cotton caused a suite of changes reminiscent of O3 exposure, including reduced root/shoot biomass allocation, reduced plant biomass production, and leaf lesions. However, applications of methyl jasmonate did not alter plant responses to O3. Further experiments are underway to investigate potential interactions between methyl jasmonate and O3 in plants. (CA). 2. In an old commercial cultivar of Pima cotton (S-6), exposure of the shoots to O3 led to genetic damage in root tips. An alkaline single cell electrophoretic assay of isolated root tip cells was used to visualize damaged DNA strands. A significant dose response of comet length, indicating damage, was found with increasing O3 exposure. These data clearly indicate that O3 impacts are systemic, and suggest that translocated products of ozonation are involved in reducing root proliferation following shoot exposure to O3. (CA). 3. Screening of 30 soybean ancestors for O3-induced foliar injury in the greenhouse was a good predictor of injury in the field using open-top chambers. However, foliar injury was not a good predictor of seed yield loss in open-top chamber studies. Specific ancestors exhibited low foliar injury with 25-30% yield loss whereas others were extensively injured with only 10% yield loss. Ozone effects on seed yield components were complex and included combinations of reduced seed size and reduced pod/seed number. These results suggest that screening of germplasm for O3-tolerance based on foliar injury alone may not take into account the full range of O3 effects on yield. (NC). Outreach 1. A picture archive of foliar O3 injury was developed at the Air Quality Learning and Demonstration Center using common milkweed as the representative plant. Concurrent with the documentation of foliar injury, air pollution levels and other meteorological data were recorded. These data enable us to train teachers and students about the progression of O3 injury development and attempt to associate O3 levels and weather patterns during symptom development. (PA)

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