Brief Summary of Minutes of Annual Meeting

Annual meeting dates and locations: May 8-9, 2003 (Raleigh, NC); May 20-22, 2004 (Fresno, CA); May 19-20, 2005 (Asheville, NC); June 19-20, 2006 (Champaign, IL); May 21-22, 2007 (Rhinelander, WI). CSREES Multistate Research Project Project No. NE-1013 Mechanisms of Plant Responses to Ozone in the Northeastern US NE-1013 ANNUAL TECHNICAL COMMITTEE MEETING Raleigh, North Carolina 8-9 May 2003 Minutes of the 2003 Annual Meeting Meeting Attendees Fitzgerald Booker, USDA-ARS, Raleigh, NC; Kent Burkey, USDA-ARS, Raleigh, NC; Art Chappelka, Auburn University, Auburn, AL; Boris Chevone, Virginia Polytechnic Institute, Blacksburg, VA; Vahram Elagoz, University of Massachusetts, Amherst, MA; Edwin Fiscus, USDA-ARS, Raleigh, North Carolina; David Grantz, Kearney Agricultural Center and UC-Riverside, Parlier, CA; Sagar Krupa, University of Minnesota, St. Paul, MN; Tim Lewis, US EPA, Research Triangle Park, NC; Bill Manning, University of Massachusetts, Amherst, MA; Meg McGrath, Cornell University, Riverhead, NY; Bahram Momen, University of Maryland, College Park, MD; Charles Mulchi, University of Maryland, College Park, MD; Russell Muntifering, Auburn University, Auburn, AL; Howard Neufeld, Appalachian State University, Boone, NC; Mike Robinson, USDA-ARS, Beltsville, MD; Marcus Schaub, Swiss Federal Research Institute, Switzerland; Bob Seem, Cornell University, Ithaca, NY; John Skelly, The Pennsylvania State University, State College, PA; The Technical Committee of NE-1013 was called to order by Chair F. Booker at 8:30 AM on May 8, 2003 in Raleigh, NC. Dr. Seem, Project Administrator, discussed final completion of the NE 176 project. All members were requested to send a publication list from annual reports 1996 to 2002 to Dr. Seem who will use this information to compile the termination report. Dr. Krupa raised concern about the lack of attendance of our CSREES representative from Washington at the past two meetings. Dr. Seem stated that this was not uncommon due to funding issues and interest of the CSREES representative. The possibility of recommending another individual from CSREES would be addressed by Dr. Seem. The comment was made that the current annual report should mention that about 50% of committee members in attendance were involved in writing or reviewing the new Ozone Criteria Document for EPA. This should be developed as an impact statement reflecting the outreach component of the Regional Project. Station research reports were then presented by respective members for the remainder of May 8 and continued on May 9. Dr. Burkey discussed the collaborative bean project utilizing tolerant and sensitive snapbeans. The experimental protocols for the bean project were presented to collaborating members and comments should be sent to Dr. Burkey prior to planting at the respective stations. A discussion of the next meeting concerned issues of attendance of the European members. A suggestion was made to hold the Technical Committee Meeting in conjunction with the Air Pollution Workshop. No consensus was reached. The meeting site and date was to be decided by Dr. Grantz after corresponding with committee members. New European members to NE 1013 included M. Schwab, J. Jaeger. A. Davidson and H. Sandermann. A motion was made and passed that two levels of membership to the committee be established: 1) full members and 2) corresponding members. Corresponding members would be those individuals interested in the research of the NE 1013 Regional Project, but are unable to attend meetings on a regular basis. Motion before the NE-1013 Technical Committee May 2003 Guidelines for NE-1013 membership and meeting attendance In order to encourage attendance at NE-1013 Annual Meetings of the Technical Committee, and to provide opportunities for collaboration and project coordination, and to provide a mechanism for maintaining current membership rolls, the following motion is proposed. Attendance by members (or a representative of that members laboratory) of one annual NE-1013 technical committee meeting within three consecutive years is encouraged. If attendance guidelines are not met, then the executive committee shall inquire into that members commitment to the project either directly or through the administrative director. If a member cannot attend regular meetings, but would like to remain affiliated with the group, a member may be classified as an adjunct member who would be kept apprised of the groups activities. This proposal is not meant to exclude or restrict membership to NE-1013, nor does it terminate membership if attendance guidelines are not met. It is intended to foster participation in the group and to provide a mechanism that allows the Executive Committee to maintain a current membership roll. Dr. Skelly requested that the committee write a letter to the PAES director stating the importance of maintaining an air pollution position at Penn State upon his retirement. The motion was made and passed that this be done and that Dr. Booker write the letter on behalf of the committee. The meeting was adjourned at 12 N on May 9, 2003. Respectfully submitted, Boris Chevone Secretary, NE 1013 CSREES Multistate Research Project Project No. NE-1013 Mechanisms of Plant Responses to Ozone in the Northeastern US NE-1013 ANNUAL TECHNICAL COMMITTEE MEETING Fresno, Parlier and Sequoia National Park, California 20-22 May 2004 Minutes of the 2004 Annual Meeting Meeting Attendees Fitzgerald Booker, USDA-ARS, Raleigh, NC; Kent Burkey, USDA-ARS, Raleigh, NC; Andrzej Bytnerowicz, USDA Forest Service, Riverside, CA; Boris Chevone, Virginia Polytechnic Institute, Blacksburg, VA; Alan Davison, Newcastle University, Newcastle upon Tyne, U.K. Dennis Decoteau, Pennsylvania State University, PA; Annie Esperanza, US National Park Service, Sequoia National Park, CA; David Grantz, Kearney Agricultural Center and UC-Riverside, Parlier, CA; Nancy Grulke USDA Forest Service, Riverside, CA; Sagar Krupa, University of Minnesota, St. Paul, MN; Tim Lewis, US EPA, Research Triangle Park, NC; Bill Manning, University of Massachusetts, Amherst, MA; Meg McGrath, Cornell University, Riverhead, NY; Bahram Momen, University of Maryland, College Park, MD; Howard Neufeld, Appalachian State University, Boone, NC; Heinrich Sandermann, Institut fuer Biochemische Pflanzenpathologie, Neuherberg, Germany; Anil Shrestha, Kearney Agricultural Center, Parlier, CA; Bob Seem, Cornell University, Ithaca, NY; Rosemary Zaleski, Exxon Mobil Biomedical Science, Annandale, NJ; Barbara Zilinskas, Rutgers University, New Brunswick, NJ; SECRETARY'S REPORT The NE-1013 Annual Technical Committee Meeting was called to order at 8:15 AM PST on May 20, 2004 by presiding chair F. Booker (USDA, NC). Welcoming comments were made by F. Booker and D. Grantz (Kearny Research Center, UC, CA), the local host, followed by introductions of the attending members. R. Seem, AES administrative advisor, remarked that the new project had been approved and is now formally operational. Ray Knighton has been designated as the new CSREES advisor to the project in Washington, DC, but could not attend the meeting due to prior commitments. Mr. Evan Shipp, meteorologist with the San Joaquin Valley, APCD, presented a talk on air quality in the valley. Violations of the 1 hr and 8 hr ozone national air quality standard are common, with 160 ppb ozone typical for 1 hr high concentrations and 155 ppb for 8 hr concentrations. In the summer, the 8 hr standard is violated almost every day downwind from the Fresno/Bakersfield metro centers. Contributing to the high ozone concentrations are NOx, reactive organic compounds, high solar radiation, weak winds/strong inversions and recirculation of air masses. Following Mr. Shipps presentation, station reports commenced. At the conclusion of the station reports, the cooperative bean project was discussed. Stations involved in the project include NC, MD, NY, MA and MN. S. Krupa (MN) indicated that environmental and air quality data are necessary for modeling efforts. He would provide the other stations with a list of minimum data required. Another potential cooperative project was proposed concerning the role of ascorbate in ozone tolerance. This project is in the developmental stages at present. Dennis Decoteau (PA), replacing J. Skelly, and Lew Ziska (USDA, MD), replacing M. Robinson, were formally accepted as members. Steve Long (IL) was unanimously approved to join the project and a letter of invitation would be extended to him by F. Booker (USDA, NC). D. Decoteau was elected as vice-chair and B. Chevone (VA) agreed to remain as secretary for the next two years. Asheville, NC was approved as the site for the 2005 meeting and H. Neufeld (NC) and A. Chappelka (AL) would serve as local hosts. F. Booker (USDA, NC) passed the gavel to H. Neufeld (NC) as the incoming chair and H. Neufeld (NC) adjourned the meeting at noon on May 21, 2004. A field tour of the Kearny Research Station followed the formal meeting, with dinner at the Grantzs home. On May 22, a tour of ozone-impacted areas in the Sequoia National Park was led by Annie Esperanza (NPS) and Nancy Grulke (USDA/FS). Respectfully submitted by, Boris Chevone Secretary, NE-1013 July 21, 2004 REPORT OF THE SECRETARY NE-1013 Annual Technical Committee Meeting May 19-20, 2005 Asheville, NC Minutes of the 2005 Annual Meeting Attendees of the NE1013 Technical Committee Meeting, 2005 Boris Chevone, VPI; Margaret Pippin, NASA Langely; Irene Ladd, NASA Langely; Jack Fishman, NASA Langely; Kirk Overmyer, NC, UNC-CH; Heinrich Sandermann, GSF, Germany; Bill Manning, MA; Kent Burkey, NC, USDA Raleigh; Margaret McGrath, NY; Don Davis, PA, PSU; Dennis Decoteau, PA; Fitz Booker, NC, USDA Raleigh; Pat Morgan, NC, USDA Raleigh; Stephanie Pilgrim, AL; Callie Nunley, AL; Steve Long , IL; John Skelly, retired, PA; John Lin, AL; Russ Muntifering, AL; Alan Davison, UK, Newcastle, U.K.; David Grantz, CA; Ray Knighton, CSREES/USDA; Cosima Wiese, PA, College Misericordia; The NE-1013 Annual Technical Committee Meeting was called to order at 8:15 AM EST on May 19, 2005 by presiding chair H. Neufeld (NC, Appalachian State Univ.). Welcoming comments were made by H. Neufeld, also the local host, followed by introductions of the attending members. Bill Jackson, USDA-FS discussed ozone impacts in Class I wilderness areas in the southeastern U.S. High ozone concentrations occur in these areas but are dependent upon weather conditions. The concentrations are sufficient to cause foliar symptoms on milkweed and tulip poplar. Ten years of ozone data across the U.S. will soon be on the web from both high and low elevation sites. To date, the TREGRO model has shown that growth of red oak and red maple are not affected by current ambient ozone concentrations. The North Carolina Clean Smokestack Bill, reductions in emissions by TVA, the Clean Air Interstate Rule and Knoxvilles attainment of the ozone NAAQS should contribute to a reduction in ambient ozone concentrations in nearby Class I areas. Ms. Irene Ladd of the GLOBE outreach project, NASA Langley, then presented aspects of the program. One objective is to develop a common level of knowledge by the public of air pollution problems in the U.S. This education is directed toward developing an interest in young people to become air pollution scientists. The program involves surface measurement of ozone using ozone sampling strips and planting ozone bio-indicator gardens. Ms. Susan Sachs from the National Park Service discussed the ozone bio-monitoring gardens in the Great Smoky Mts. There is more SOx and NOx in the Smokies than in any other National Parks. Three species have been planted in the indicator gardens and include crownbeard (Verbesina occidentalis), cutleaf coneflower (Rudbeckia laciniata) and tall milkweed (Asclepias exaltata). Symptoms of stippling, chlorosis and necrosis are recorded weekly at three elevations and are animated over time to show the progression of foliar injury during the summer. Following Ms. Sachs presentation, station reports commenced. At the conclusion of the station reports, F. Booker (USDA, NC) discussed the NE1013 web page. The page has links to members of the project and to other sites showing ozone effects to vegetation. The URL is: http://www.ncsu.edu/project/usda-ne-1013/. Illinois was selected as the site of the next meeting and S. Long would be the local host. The project renewal was then discussed and has to be submitted by September 2006. The committee to develop the renewal consisted of D. Decoteau, chair (PA), S.Krupa (MN), B. Chevone (VA), A. Chappelka (AL) and D. Grantz (CA). A draft of the renewal is to be completed by the May Technical Committee Meeting, 2006. H. Neufeld formally closed the meeting at 12 noon, May 20, 2005. Formally submitted by, Boris Chevone Secretary, NE-1013 July 28, 2005 REPORT OF THE SECRETARY NE-1013 Annual Technical Committee Meeting June 19-20, 2006 Champaign, IL Minutes of the 2006 Annual Meeting Meeting Attendees Ainsworth, Lisa - University of Illinois; Bernacchi, Carl - Illinois State Water Survey; Burkey, Kent - USDA ARS; Chappelka, Arthur - Auburn University; Chevone, Boris - Virginia Polytechnic Institute; Decoteau, Dennis - Pennsylvania State University; Knighton, Raymond - USDA CSREES; Krupa, Sagar - University of Minnesota; Leakey, Andrew - University of Illinois; Long, Steve - University of Illinois; Manning, William - University of Massachusetts; Morgan, Patrick - USDA ARS; Sandermann, Heinrich - Frieburg, Germany; Wittig, Victoria - University of Illinois; Zilinskas, Barbara - Rutgers University; The NE-1013 Annual Technical Committee Meeting was called to order at 8:15 AM EST on June 19, 2006 by S. Long (IL) as presiding chair-elect D. Decoteau (PA) was delayed by inclement weather. Committee chair Howard Neufeld was unable to attend the meeting due to weather. Welcoming comments were made by S. Long the local host who mentioned the continuous crop plots started in the 1870s at the University of Illinois and the current SoyFACE project where a 20% yield loss of soybean has been observed under ambient ozone concentrations. Introductions by the attending members then followed. S. Krupa (MN) briefly discussed the draft renewal of NE1013 project. R. Knighton, the National Program Leader for Air Quality and the NE-1013 CSREES/USDA advisor, remarked that a major program concern was the contribution of agriculture to air quality. He further commented that the emission of ammonia, particulates and animal-produced reactive VOCs in relation to ozone production was an important consideration. Ammonium in rainwater is increasing and the contribution from crop production is not known. Several committee members then raised a concern that the research focus of NE-1013 has been the effects of air quality (ozone) on crop production and the health of native vegetation. Most members expressed concern about continuing in the program if research emphasis shifted to a monitoring/modeling effort from an effects/mitigation effort. Station reports were then presented. After the station reports, discussion ensued concerning the collaborative effort of the snapbean project. One purpose of the project was to determine the contribution of ambient ozone levels to yield loss of the sensitive cultivar compared to the tolerant one. This information was deemed important to US EPA to consider when setting the ozone standard. A discussion then began on the renewal of NE-1013. Several areas were mentioned for inclusion in the renewal and the topics/coordinators were natural vegetation/A. Chappelka; water quality/air quality/B. Momen (MD); mechanisms and adaptation/S. Long and K. Burkey; education and outreach/D. Decoteau; and biomonitoring/W. Manning. R. Knighton suggested in the future that station reports, either oral or written, should be directed toward specific objectives of the existing proposal. Potential new members included N. Grulke (USFS, CA) and D. Karnosky (Michigan Tech, MI). The meeting site for next year was selected as Rhinelander, WI. D. Decoteau adjourned the meeting at 12N on June 20, 2006. Respectfully submitted, B. Chevone Secretary NE1013 Virginia Tech Blacksburg, VA CSREES Multi-State Research Project NE-1013 Mechanisms of Plant Response to Ozone in the Northeastern US Holiday Inn Express, Rhinelander, WI May 21-22, 2007 Minutes of the Meeting of the Technical Committee Attendees: Lisa Ainsworth, USDA-ARS, Urbana, IL; Fitzgerald Booker, USDA-ARS, Raleigh, NC; Kent Burkey, USDA-ARS, Raleigh, NC; John Carlson, Pennsylvania State University; Dennis Decoteau, Pennsylvania State University; David Grantz, University of California, Riverside; Nancy Grulke, US Forest Service, Riverside; Dave Karnosky, Michigan Technological University; John King, NC State University; Raymond Knighton, USDA-CSREES, Beltsville, MD; Mark Kubiske, US Forest Service, Rhinelander; Rainer Matyssek, Technical University of Munich, Germany; Margaret McGrath, Cornell University; Russ Muntifering, Auburn University; Neil Nelson, US Forest Service, Rhinelander; Howard Neufeld, Appalachian State University; Kevin Percy, Canadian Forest Service; Heinrich Sandermann, Ecotox, Germany; Cosima Wiese, College Misericordia; Barbara Zilinskas, Rutgers University; The meeting was called to order on May 21, 2007 at 9:00 a.m. 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. The committee was invited to submit information to Ray about ozone effects on specialty crops that he could take into consideration when formulating the RFPs for the new USDA initiative on specialty crops. Station reports were then presented. 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 need to be approved in 2008. 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. NE-1013 Annual Reports for the period of June 2006 to May 2007 are due to F. Booker by June 25, 2007. All committee members from land grant universities are required to submit annual reports, which basically contain the same information as annual CRIS Form AD-421, including publications. Fitz will summarize and submit along with meeting minutes. 5. An NE-1013 termination report is due for submission to our CSREES administrator no later than March 31, 2008. Station termination reports should be sent to Fitz by February 15, 2008. The termination report is very similar to the annual report except that accomplishments, impacts and publications cover the entire span of the project. The following people agreed to help compose the termination report: Objective 1. (Describe the spatial - temporal variability of the adverse effects of ozone on crops and forests - Meg McGrath and Dennis Decoteau; Objective 2. (Assess the effects of ozone on structure, function and diversity of plant communities) - Russ Muntifering and Howie Neufeld; Objective 3. (Examine the joint effects of ozone with other growth regulating factors on crop and tree growth and productivity)- Fitz Booker and Dave Grantz; Objective 4. (Examine the molecular and physiological basis of ozone toxicity and tolerance in plants) - Barbara Zilinskas, Kent Burkey; Objective 5. (Develop numerical models to establish relationships between ambient O3 exposures and plant responses) - Sagar Krupa. 5. A report of the meeting is required by the EPA for funding that has been received. Howie Neufeld has $10,000 for travel. He needs official receipts for airplane, hotel and other expenses, except food receipts. He can handle partial reimbursement requests. 6. Kent Burkey provided an update on the snap bean project status. NJ, NC, PA, and NY will continue this research in 2007. The experiment may also be conducted in CA; however, the excessive heat occurring when ozone concentrations are highest may necessitate doing the work during the winter vegetable growing season when ozone levels are much lower. 7. Meg McGrath was elected next Secretary to replace Russ Muntifering, the current Secretary. 8. Potential meeting locations were discussed. Next years meeting of the new NE-1030 project will be in the spring of 2008 at Auburn University, hosted by Art Chappelka and Russ Muntifering. 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 attempting to see how ozone alters the response of Northern forest ecosystems to elevated carbon dioxide. He discussed the variability displayed in growth responses to these two interacting gases, both interspecific and intraspecific. Later in the program, Dave led a field trip to the Aspen FACE project, which included a walk through of the four rings in the north replicate of the 12-ring experiment that covers some 20 ha on the USFS Harshaw Farm. Respectfully submitted, R. Muntifering Secretary NE1013 Auburn University Auburn, AL

The NE-1013 Project was organized into five distinct objectives. The Accomplishments of this successful collaboration are presented by Objective, below. The Impacts of these activities are then presented, integrated over all Objectives. At the conclusion of this 5-year project, the membership successfully prepared a renewal application, approved as NE-1030 for the 5-year period through September 30, 2012. This project has been fundamental to increased understanding of ozone effects on plants. The collaborative effort has been the primary vehicle for such research in North America during this period. Meeting participants came together from 15 universities, two federal agencies and four foreign countries, produced 120 peer-reviewed publications on ozone impacts, numerous book chapters, and four theses, and conducted a wide array of research and outreach activities. Several of the Technical Committee Members served as peer reviewers of the US. EPA 2006 Criteria Document for Ozone and Other Photochemical Oxidants. Much of the relevant new data regarding Welfare Effects and the associated Secondary Air Quality Standard for Ambient Ozone was developed by members of this project. Additionally, the project provided background briefing documents to the USDA Air Quality Task Force on Ozone Research and Vegetative Impacts and on Ozone Effects on Specialty Crops, to support preparation of the 2008 Farm Bill and to use in advising the Secretary of Agriculture regarding air quality policy. We also participated in reviews of the IPCC Fourth Assessment Report on Climate Change. The project has maintained a comprehensive web page since 2005, and regularly updates the site (http://www.ncsu.edu/project/usda-ne-1013/index.htm) with current information. Objective 1. Describe the spatial - temporal variability of the adverse effects of ozone on crops and forests. Adverse effects of ozone on crops and forests were investigated through experiments conducted with plants exposed to ambient ozone in various locations and time periods to achieve a diversity of ozone exposures. For example, the behavior of bean (Phaseolus vulgaris L.) selections R331 (tolerant to ozone) and S156 (susceptible to ozone) were compared in field plot evaluations over several planting dates, years and locations (states). Ambient ozone caused severe injury to leaves and defoliation in the ozone-sensitive snap bean cultivar, S156, across all of the tested locations and years. Total weight of bean pods harvested for fresh-market consumption was 40 to 56% lower for S156 compared with the tolerant genotype when ozone concentrations were considered to be moderate to high. The R331 and S156 lines typically yielded similarly under low ozone concentrations, which usually occurred during the first or last planting dates at some of the sites. Overall, there was little spatial or temporal variability in the response of these bean lines to ambient ozone. Damage occurred at ambient ozone levels in the sensitive line at a number of locations and over several years except when ozone concentrations were low. In a similar type of study, biomass production of ozone-sensitive and ozone-resistant clones of the commercial white clover line (Regal) were compared in New York. The sensitive clone was more severely injured and exhibited up to 26% reduction in biomass production relative to the resistant clone when ambient ozone concentrations were high. The clones grew similarly when concentrations were low. In contrast to the bean and clover studies, the amount of injury observed on grape foliage varied from year to year and was influenced by weather conditions. A study with Charbourcin grape in Pennsylvania found that ambient ozone injury included adaxial stipple and yellowing and defoliation of the older leaves. The drought of 2005 may have reduced foliar ozone injury compared with other years due to lowered ozone uptake. Also wet and cloudy conditions of 2003 and 2004 contributed to reduced seasonal ambient ozone levels, which coincided with less injury. The Vidal variety of grape, which is considered tolerant to ozone injury, typically exhibited no foliar injury to ambient ozone levels. Ambient ozone levels in the forests of western Virginia are sufficient to cause differential responses in ozone-sensitive and tolerant black cherry trees. Sensitive black cherry exhibited greater foliar injury symptoms and lower photosynthetic rates. These results demonstrate that even low ozone levels (in the 50 to 60 ppb range) can damage carbon assimilation processes in sensitive trees. Surprisingly, in Alabama, tree ring data from black cherry indicated that radial growth did not vary among ozone sensitivity groups during any time period analyzed. In a study of native cutleaf coneflower (Rudbeckia laciniata) in the Great Smoky Mountain National Park, we found ozone injury to vary both spatially and temporally. These responses were not well correlated with ozone concentrations. In fact, injury was observed in relatively low-ozone years, indicating that this native plant can be quite sensitive to ozone, depending on other environmental conditions. Micro-site (seasonal rainfall or temperature patterns) and genetic factors influence plant sensitivity to ozone. In addition, it was found that sensitive coneflower developed injury earlier in the season than insensitive plants. Older leaf cohorts were more likely to exhibit the greatest percent injury by the end of the growing season. Also, leaf loss was more likely for older cohorts and lower leaf positions than in younger cohorts and upper leaves, respectively. Failure to take these factors into account can result in underestimation of the effects of ozone on these plants. Clearly, these results showed that medium to high ambient ozone concentrations can damage vegetation and reduce yields, but that genetic and environmental factors strongly modulate the responses. Objective 2. Assess the effects of ozone on structure, function and diversity of plant communities. The overall goal of Objective 2 was to assess the effects of ozone on structure, function and diversity of plant communities, notably forests and grasslands. Results have provided critically needed data on physiological and growth responses of mature trees and understory herbaceous species in the field under a range of ambient ozone exposure regimes. We determined changes in tree growth under ambient ozone conditions and elucidated underlying mechanisms responsible for differences in sensitivity of native wildflower species. Also, we characterized alterations in cell-wall constituents and secondary metabolites in ozone-exposed herbaceous vegetation that have implications to the nutritional ecology of economically important ruminant animals. Information needs in these areas have been identified as critical for the assessment of ozone pollution effects in natural ecosystems. One of the fundamental differences identified by testing responsiveness of understory herbaceous species to rapid changes in light is that ozone-sensitive plants, such as cutleaf coneflower, have impaired stomatal functioning, such as non-responsiveness to changes in humidity or light compared to ozone-insensitive plants. It was found that ozone-sensitive plants fail to close their stomata under conditions where insensitive plants would, leading to reductions in water use efficiency and continued uptake of ozone by the plant, which contributes to ozone injury. Ecosystem function can be altered by several processes, one of which is differential reproductive success. We found that reproductive effort of selected native plant species was affected by ozone. These effects can be translated into alterations in flowering patterns and abortion of seeds/fruits, and have implications regarding establishment, survival, genetic stability and vigor of these species. Ozone reduces photosynthesis in native plants, especially in their older leaves, which translates into reduced starch reserves in these leaves and the underground rhizomes. Plants known to be sensitive suffer greater reductions in photosynthesis than those that are insensitive. Sensitivity in one herbaceous species was linked to extracellular levels of the antioxidant ascorbic acid, suggesting that both uptake and biochemical detoxification are important mechanisms of response in these native plants. Research under this objective has shown that, as a result of accumulation of secondary phenolic compounds, increased deposition and lignification of cell-wall constituents and decreased in vitro digestibility in a number of ozone-sensitive plant species, predicted loss of forage nutritive quality for ruminant animals due to ozone injury can readily approach the same order of magnitude as that observed for biomass yield depression (ca. 5-15%). These are extremely important findings because total loss of consumable food value (fractional reduction in yield × fractional reduction in nutritive quality for ruminants) can be much more significant than biomass yield reductions alone in the assessment of the true economic impact of ozone on forages under current and future global-climate scenarios. Using ethylene diurea (EDU, an antioxidant protectant for plants) it was found that in purple coneflower (Echinacea purpurea), EDU could ameliorate the deleterious effect of ozone on nutritive quality. Further testing is needed in this area to determine if this is response is evident among other plant species. Until recently, economic assessment models have included only the effects of yield depression. Results of research under this objective also illustrate the value of both 'real-world' and manipulative experiments, and the importance in climate-change/nutritional ecology research of assessing effects of co-exposure to environmentally relevant levels of multiple air pollutants. For example, ground-level ozone, temperature and precipitation were observed to be the most important determinants of nutritive quality in a 5-year study with alfalfa grown under ambient concentrations of multiple air pollutants (ozone, nitrogen oxides, sulfur dioxide) and prevailing meteorological conditions, but their relative importance was largely dependent on yield such that ozone exposure was the most important determinant of quality in high-yielding but not in low-yielding alfalfa. We have observed in both intensively managed and semi-natural systems that adverse effects of ozone on forage quality may be amplified by high soil fertility or exposure to growth-stimulating levels of atmospheric N deposition compared with low soil fertility or growth-limiting levels of N deposition, respectively. We have discovered in our work with red (Trifolium pratense) and white (Trifolium repens) clover that, in contrast to recent reports of a protective effect of elevated atmospheric carbon dioxide against yield reduction in plants under ozone stress, future increases in atmospheric carbon dioxide concentration might not be expected to ameliorate the negative impact of elevated ozone on nutritive quality under global chemical-climate scenarios projected for the Northern Hemisphere through at least the first half of the 21st Century. Objective 3. Examine the joint effects of ozone with other growth regulating factors on crop and tree growth and productivity Nutrition The atmosphere has become a source of bioavailable N as well as oxidizing species such as ozone. Observations in a long-term experiment in a sub-alpine pasture in Switzerland examined the impact on pasture nutritive quality of the combined impacts of ozone and high N input. A pasture exposed to ozone and N deposition in Switzerland showed that nutritive quality was 7% lower for elevated ozone treatments due to altered cell-wall chemical composition. There were long term changes in vegetative composition as well, with forbs increasing from 23 to 36%, and grasses and legumes both decreasing (from 68 to 60%, and from 9 to 3% of biomass, respectively). Weeds and Invasive Vegetation Competition relationships between crops and weeds can be altered by concurrent exposure to ozone. However, knowledge of the ozone tolerance of individual species has not proven useful in predicting the outcome of inter-specific plant competition in open top chambers studies in the San Joaquin Valley of California. For example, competition between Pima cotton and the globally significant C4 weed, yellow nutsedge (Cyperus esculentus L.) was affected substantially by ozone exposure. Cotton was generally more sensitive to ozone than nutsedge, and both competition from nutsedge and exposure to ozone reduced productivity of cotton. The two species inhibited the growth of each other to similar extents. At a high ozone concentration productivity of cotton was low, but the relative reduction by nutsedge competition at high ozone was similar to that at low ozone concentration. Growth of nutsedge in competition with cotton was greatest at high ozone, as the vigor of cotton declined. In contrast, similar competition studies with tomato, which is somewhat more ozone tolerant than cotton, led to differing results. Tomato became more competitive at high ozone. Tomato growth was inhibited at the highest ozone concentration at all levels of nutsedge competition, while nutsedge was less affected. Nutsedge reduced tomato productivity under low and moderate ozone concentrations, but tomato was more competitive at high ozone concentrations. Nutsedge allocated greater resources to reproductive tubers at the highest ozone exposure which could make it even more invasive in future environments. Horseweed is an economically important C4 weed that is becoming increasingly invasive in areas like the San Joaquin Valley. Glyphosate-resistant horseweed has almost completely replaced the wild-type, glyphosate-susceptible, biotype. Results of research conducted by this project suggest that ozone may be a significant contributor to this rapidly changing population structure. Responses to ozone are similar in glyphosate-sensitive and -resistant lines. However, additive effect of ozone and glyphosate is sufficient to drive the glyphosate-sensitive population to extinction. The resistant biotype was less likely than the susceptible biotype to being driven out of the population by the combination of high ozone and glyphosate. Thus ozone may contribute to the rapid evolution of herbicide resistance and to rising crop production costs due to increased need for vegetation management, in addition to the well known effect of reducing yield directly. This is the first indication that tropospheric ozone may be a contributory factor in development of a serious agricultural pest through altered population structure. Elevated Carbon Dioxide Ozone is a component of the changing atmosphere, and will play a part in ongoing Global Change. A soybean-corn rotation open-air exposure experiment showed that for soybean, elevated carbon dioxide increased biomass and seed yield, elevated ozone decreased biomass and yield, and the deleterious effects of ozone were partially ameliorated by carbon dioxide when the two gas treatments were combined. This and other studies have indicated that protection against ozone injury in many crops by elevated carbon dioxide can be attributed to reduced ozone uptake and possibly other factors, but there has been little direct testing of these hypotheses. Manipulation of ozone concentrations and estimates of plant ozone uptake indicated that equivalent ozone fluxes that suppressed net photosynthesis, growth, and yield at ambient concentrations of carbon dioxide were generally much less detrimental to plants treated concurrently with elevated carbon dioxide. These responses appeared unrelated to effects on antioxidant metabolism. Plants treated with elevated carbon dioxide had higher rates of net photosynthesis due to higher intercellular carbon dioxide concentrations. Increased photoassimilation and decreased photorespiration with elevated carbon dioxide would promote growth and help counter detrimental effects of ozone. Increasing concentrations of atmospheric carbon dioxide will likely ameliorate ozone damage to many crops due to reduced ozone uptake and increased carbon assimilation. Our study further suggests that elevated carbon dioxide may increase the threshold ozone flux for biomass and yield loss in soybean. An experiment designed to test the effects of elevated carbon dioxide and ozone on soil carbon and nitrogen dynamics in a soybean-wheat no-till system using open-top chambers showed that elevated carbon dioxide increased soybean and wheat biomass production by 10 to 25% while ozone suppressed it by 11 to 27%. In combination, elevated carbon dioxide ameliorated ozone effects on biomass. Treatment effects on biomass production dominated potential impacts on soil carbon dynamics as evidenced by litter levels in the treatment plots and minirhizotron images of root production. Two winter-wheat cultivars, Gore and Susquehanna, were treated with elevated carbon dioxide and ozone individually and in combination. Elevated carbon dioxide resulted in stomatal closure and, under low ozone, induced antioxidant changes that could enhance defensive capacity for oxidative stress. Yield under the combination of elevated ozone and carbon dioxide tended to be greater than for elevated ozone alone. The results suggest that plant response to ozone depends upon a number of factors working together. The availability of high pools of antioxidants in wheat may further contribute to enhanced oxidative defense capabilities. The AspenFACE experiment indicated that northern forests have the capacity for sustained growth stimulation due to elevated carbon dioxide, and that concurrent exposure to moderate levels of tropospheric ozone partially or totally compromises growth stimulation from elevated carbon dioxide. Also, elevated carbon dioxide and ozone have small effects on litter chemistry and specific rates of decomposition, while changes in litter inputs under elevated carbon dioxide and ozone will likely have large effects on soil organic matter. Objective 4. Examine the molecular and physiological basis of ozone toxicity and tolerance in plants. Systemic effects of ozone Ozone immediately affects leaf tissue; however, ozone can cause systemic effects on the whole plant. In snap beans, ozone treatment increased shoot respiration based on elevated metabolic heat rates measured with a microcalorimeter. In both Pima cotton and muskmelon, ozone-induced inhibition of carbon assimilation and transport of carbohydrate from shoots to roots did not cause the expected reduction of root respiratory activity. As source strength and transport of carbohydrate to sink tissues declined, root respiration per unit fresh weight increased. The mechanism of these seemingly disparate phenomena remains unknown. However, these findings suggest that the hypothesis that substrate control of root respiration, as it is modulated by ozone impact on shoot tissues, may not be supported. In Pima cotton, exposure of the shoots to ozone led to genetic damage in root tips as visualized by an alkaline, single-cell electrophoretic assay of damaged DNA in isolated root tip cells. DNA damage increased with increasing ozone exposure. The results clearly indicate that the effects of ozone on vegetation are systemic, and suggest that translocated products of ozonation, or other signal transduction processes, are involved in reducing root proliferation following shoot exposure to ozone. Root growth is often inhibited by ozone and has been primarily attributed to reduced availability of carbon resources needed for growth. The finding that ozone induces genetic damage in root tips adds a new dimension to our understanding of the mechanisms of ozone toxicity. Methyl jasmonate caused a suite of developmental changes reminiscent of ozone exposure. These preliminary experiments were in response to recent gene expression studies that link jasmonate metabolism to ozone impacts. In our experiments, application of methyl jasmonate induced responses very similar to those of ozone. These similarities were sufficient to suggest that ozone-induced developmental or injury pathways were modulated by methyl jasmonate. However, application of methyl jasmonate in our experiments did not alter plant responses to ozone, indicating that ozone effects are propagated through a network of metabolic pathways and cellular processes that are only partly modulated by methly jasmonate. These and similar studies are important because they help us disect the biochemical and physiological mechanisms of ozone toxicity which may contribute to the engineering of ozone-tolerant crops. Stomatal conductance in relation to ozone tolerance Stomatal conductance was similar for ozone-sensitive (S156) and tolerant (R123) snap beans. While genetic variation was found for stomatal density and aperture on upper and lower leaf surfaces, these differences in stomatal characteristics did not translate into differences in conductance rates, suggesting that the observed genetic variation in ozone response is not related to differences in ozone uptake. Ascorbic acid metabolism Ascorbic acid (known also as vitamin C) is generally acknowledged to play a key role in plant response to oxidative stressors, including ozone. In Arabidopsis, a putative F-Box gene, VCF1 (Vitamin C F-box 1), was identified that appears to negatively regulate gene expression in the mannose-galactose pathway of ascorbate biosynthesis. Plants in which VCF1 was inactivated had increased leaf ascorbate content and enhanced tolerance to ozone. Photosynthesis in mature leaves of soybean was more sensitive to ozone exposure in the cultivar Forrest than in cultivar Essex. The ozone tolerance of Essex was associated with enhanced capacity to maintain ascorbate in the reduced form. The research provided further evidence that reduced ascorbate is an important antioxidant and the ascorbate-glutathione cycle plays a role in protecting the photosynthetic apparatus from ozone-induced damage. Genetic variation in ozone response Thirty soybean ancestors representing 92% of genes in modern U.S. and Canadian cultivars were screened for ozone sensitivity. Two ancestors, Fiskeby III and Fiskeby 840-7-3, exhibited minimal foliar injury when exposed for six-days to 80 ppb ozone under greenhouse conditions and maintained yield under elevated ozone treatments during season-long exposures in open-top chambers. However, foliar injury in general was not a good predictor of seed yield loss. 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 ozone-tolerance based on foliar injury alone may not be the ideal or appropriate predictor of ozone effects on yield. Antioxidants localized in the leaf apoplast and cell wall have the potential to scavenge ozone and ozone-derived reactive oxygen species thought to be involved in initiating foliar injury responses. The leaf apoplast from ozone-sensitive and tolerant genotypes of soybean and tobacco contained low levels of ascorbic acid relative to total antioxidant capacity, evidence that soluble compounds other than ascorbate may contribute to ozone scavenging reactions. Soybean genotypes expressing differential ozone sensitivity also exhibited differences in composition of cell wall bound phenolic compounds. These results suggest that research on antioxidant mechanisms of ozone tolerance should be broadened to include other types of leaf chemistry in addition to the work being done on ascorbic acid. G-proteins The molecular signals that initiate ozone responses in plants are thought to originate in the leaf apoplast, but the mechanisms involved in sensing and propagating these signals are not known. Since GTPases (G-proteins) are involved in plant defense responses that share common features with ozone responses, Arabidopsis G-protein null mutants were tested for ozone sensitivity. Mutants with key deletions in the G-protein pathway did not exhibit the leaf epinasty observed in Columbia wild-type controls following ozone exposure, evidence that this particular phenotypic response to ozone is at least partially G-protein dependent. Biomass production, chlorophyll levels and photosynthesis rates were slightly lower in the G-protein null mutants following chronic ozone exposure. However, induction of peroxidase enzyme activity by ozone was similar in both G-protein mutants and wild-type controls. The results indicate that stimulation of peroxidase activity by ozone does not involve G-protein signaling processes. Ozone effects likely involve multiple pathways and cellular processes. Suppression of the G-protein signaling pathway in Arabidopsis did not markedly increase its sensitivity to ozone, which suggests that other processes compensated for the genomic changes or other modes of action are more critical in the etiology of ozone toxicity. Objective 5. Develop numerical models to establish relationships between ambient ozone exposures and plant responses. Alfalfa (Medicago sativa) cv. Beaver was grown under ambient conditions at multiple sites using the local grower cultivation practices. There were two harvests per growth season per plot (with 6 replicates). Since alfalfa cultivation was on a five-year rotation cycle, each year a new seeding was done on separate study plots and harvested, starting with the year after seeding and during the following four years, with a total 78 harvests, but with differing age classes (2-5 years). Alfalfa and total biomass (alfalfa + other plant species, weeds) yields varied between the two harvests at a given site during a given year and between sites and years, although there was no carry-over effect of stress from one harvest to another. Using the median yield value for all sites and years combined, separately for alfalfa and for total biomass, data were segregated into two statistically differing classes: lowand high. Alfalfa yields for low ranged from 85 to 17% of the median and from 117 to 218% for high. Similarly for total biomass yield values for lowranged from 83 to 32% of the median and from 117 to 197% for high. The lowand highwere treated separately in the yield modeling of the alfalfa and the total biomass. The air quality and meteorological variables were defined separately for each of three growth stages (time series) for use in the yield models. The independent variables in each stage were: ozone (median and 95th percentile hourly concentrations), sulfur dioxide and oxides of nitrogen exposure integrals (concentration x exposure duration) and temperature, relative humidity and global solar radiation, and precipitation depth totals. Mallows Critical Point Best regression was used to select the best yield models for further application. The initial analyses were done for alfalfa and total biomass separately, but with all yields, sites and years combined, the results giving very satisfactory values for both adjusted coefficient of variation (68-76%) and its significance p (0.000). Hourly ozone concentrations, the median and equal to or greater than the 95th percentile values were selected as important predictors of both alfalfa and total biomass yields. In addition to ozone, some of the other important predictors of yield included sulfur dioxide, oxides of nitrogen, temperature, global radiation and relative humidity. Overall the models could account for 68 to 76% of the R2 variability in the yields of alfalfa or the total biomass respectively. Air quality (ozone + sulfur dioxide + oxides of nitrogen) influenced about 50% of the total variation in all of the alfalfa yields combined, with ozone accounting for one-half of it. The remaining 50% was due to variations in the climate and parameters that were not measured. Similar results were also obtained in the case of the total biomass. These results have been disseminated to the scientific community through USDA-NE1013 Annual Technical Committee Meetings and currently three journal articles are in preparation.

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