REPORT OF THE SECRETARY

NE -1013 Annual Technical Committee Meeting

May 19-20, 2005

Asheville, NC

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. R. Knighton, the National Program Leader for Air Quality and the NE-1013 CSREES/USDA advisor, remarked that the budget proposal in Washington requested reducing Hatch Funds by half in the coming year and eliminating these funds entirely in the following year. The House budget proposed increased funding by $100K and the status of the Funds remains to be determined. The NRI competitive program in air quality has a deadline of June 15, 2005 for proposals. The principal focus of the program is agricultural emissions impacting air quality, not the impacts of air quality on agricultural production. A National Air Quality Workshop will be held June 5-8, 2006.

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. There are numerous ozone monitoring locations throughout the region, and the data are used as input into a vegetation effects model and to increase public awareness of air quality problems. 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. Changes in air quality in the southeast from 1995 to 2001 have been documented by SAMI. The North Carolina Clean Smokestack Bill, reductions in emissions by TVA, the Clean Air Interstate Rule and Knoxville’s 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. In addition, the pH of rainwater averages around 4.5 and mean visibility in the summer is only nine miles. 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.

D. Decoteau (PA) discussed the Air Quality Learning and Demonstration Center at Penn State University. A three-credit summer course is given to K-12 science teachers that is required by the state to maintain certification. An open top chamber study demonstrated that foliar symptoms on Chambourcin grapes is caused by ambient ozone. The ozone effects on wine production and quality are being evaluated.

M. McGrath (NY) summarized results of research conducted in 2004 to assess the impact of ambient ozone on sensitive and tolerant snap bean lines growing on Long Island, NY. 2004 was a low ozone year, but injury and defoliation still occurred on the sensitive genotype. Yield reduction of fresh pod weight for both harvests 1 and 2 was 46% compared to the tolerant line. In the three previous years, with higher ozone concentrations (2195 ppb*h versus 1601 ppb*h), pod yield reductions were only 36%. Several committee members suggested that ozone flux to the leaf interior may be responsible for these unusual results and that moisture during the growing season should be evaluated.

R. Muntifering (AL) presented data on studies of biomass production and nutrient quality of gamma grass in open top chambers (OTC) with CF, NF and 2X ambient ozone. Biomass was 7.3, 9.5 and 14.1 g/pot in CF, NF and 2X ambient ozone which was an unusual response. However NDF (neutral detergent fiber) increased and RVF (relative food value) decreased by 6% which is significant for product price and animal nutrition. In the re-growth samples, lignin increased from 1.7 to 2.5% and RVF decreased from 90 to 75% in 2X chambers compared to CF chambers. Re-growth biomass was 7.9, 10, and 7.7 g/pot in CF, NF and 2X treatments. Nutrient quality of Trifolium species was also investigated in OTCs in response to N application of 5, 15 and 30 kg/ha. Across all treatments, exposure to NF + 40 ppb ozone decreased nutritive quality of Trifolium species by an average of 13% compared to CF and NF treatments. This decrease occurred at ozone concentrations 60% less than the UN/ECE Critical level of AOT40 = 3000 ppb*h for protection of semi-natural vegetation. Trifolium species are substantially more sensitive to ozone with respect to nutrient quality than gamma grass.

S. Krupa (MN) discussed alfalfa response to ambient air quality and climate variables at three study sites in Alberta, Canada over a five-year cycle. A total of 68 harvests (two harvests each year) were used to model alfalfa growth rates and biomass yield in relation to ozone, SO₂, NO_x and various meteorological variables. Growth rates, biomass, stem count and weeds were monitored as plant variables. Biomass harvests that differed between the harvests, sites and years, were categorized as “low” or “high”. A multivariate statistical model demonstrated that ozone, SO₂, NO_x, climate and unknown variables contributed to 26, 25, 26, and 23%, respectively, of the yield effects and that ozone was the most important air pollutant reducing biomass. The second harvest was less affected by ozone than the first harvest. The amount of weeds in the plots did not affect growth rate or yield. Since SO₂ and NO_x, in low concentrations can act as nutrients, it was not known whether these pollutants had positive or negative effects on alfalfa growth.

J. Skelly (PA, retired) presented a brief review of the Air Pollution Workshop which began in 1969. The 38th workshop will be held in Charlottesville, VA in 2006 with the theme “Air Quality Issues within National Parks and Wilderness Areas.”

W. Manning (MA) stated that most of southern New England is in non-attainment for ozone with the Quabbin Reservoir in central Massachusetts having the highest ozone concentrations in the state. The snapbean varieties S156 (ozone sensitive) and R123 (ozone tolerant) have different phenotypic characteristics. R123 are large plants with large leaves and show little foliar visible injury when exposed to ambient ozone. In contrast, S156 are smaller plants with small leaves and considerably more leaf injury. S156 however, has more stomates/mm2 and a higher leaf conductance than R123. When ozone exposures were increased from 30 ppb to 60 ppb, stomatal density increased in S156, but was unchanged in R123. Stomatal density and aperture are different in the two bean selections and may allow a greater ozone flux into the leaf interior in S156 which could account, in part, for the greater sensitivity of this genotype.

H. Neufeld (NC, Appalachian State Univ.) discussed research results on stomatal behavior and reproduction in ozone tolerant and sensitive genotypes of coneflower (Rudbeckia laciniata). During mid-day, coneflowers wilt, however there is a ten minute delay between wilting and a reduction in stomatal conductance. Assessment of the role of leaf conductance in ozone sensitivity indicated that there is no difference in stomatal density between the two genotypes, but that sensitive plants have lower conductance. The sensitive genotype also had lower quantum efficiency, net photosynthetic rate (30%) and a higher CO₂ compensation point than insensitive plants. The VPD response of stomata was also different between the genotypes, being less responsive in the sensitive plants. The net photosynthetic rate declines more in sensitive plants than insensitive ones as the leaf ages and therefore less CO₂ is fixed. Sensitive plants had 34% fewer flower heads and 30% fewer seeds per flower head than insensitive plants, thereby producing 56% fewer seeds per plant.

A. Davison (Univ. of Newcastle, UK) presented results on ozone effects in the field on cone flower net photosynthesis and chlorophyll fluorescence (Fv/Fm and fluorescence area, FA). A significant relationship between leaf injury and FA was noted, but the association between Fv/Fm and net photosynthesis was weaker. FA does appear to be a useful measure of ozone effects and light saturated net photosynthesis.

S. Long (IL) discussed research at the FACE site in Illinois with CO₂, O₃ and CO₂ + O₃ treatments. Soybean yield loss to ozone was 40% at 50 to 60 ppb for 7 h daily. Ozone effects included a lower electron transport rate and lower net photosynthesis to xanthophyll ratio. CO₂ treatment delayed development by seven days. CO₂ lowered soybean Ca content but no effect on Ca occurred with ozone exposure. However, ozone lowered net photosynthesis, Rubisco content, seed number and shoot and root biomass which all contributed to the yield loss. In Arabidopsis, low ozone concentrations down-regulated more genes than in control treatments.

P. Morgan (IL) presented results of elevated ozone (70 ppb, 7 h/day) effects on soybean growth and photosynthetic capacity. Ozone caused a 20% loss in seed yield. In youngest, fully expanded leaves at the top of the canopy, ozone did not affect light-saturated photosynthesis, carboxylation efficiency or maximum electron transport. Leaves formed during vegetative growth did not lose photosynthetic capacity as they aged, however, leaves formed during reproductive growth showed a 20 to 30% loss in carbon fixation capacity as they aged. This loss in carbon assimilation during reproductive growth will affect final yield in ozone-stressed soybean.

F. Booker (UDSA, NC) reported that ozone flux to soybean leaves growing in pots in open-top chambers was suppressed by elevated CO₂. High CO₂ reduced ozone injury and induced partial stomatal closure. Elevated ozone contributed to protein loss, but increased ascorbic acid levels and peroxidase activity. Elevated CO₂ protected plants from ozone injury, but apparently by mechanisms not just involving a reduction in ozone flux. The mechanisms may be related to increased net carbon assimilation and ascorbic acid levels at elevated CO₂.

D. Grantz (CA) discussed ozone effects on weed/crop competition. In the nutsedge/tomato combination, an increase in ozone levels resulted in a competitive advantage to tomato. In the cotton/nutsedge combination, increased ozone favored the competitive ability of nutsedge. In centric translocation lines of rye-wheat, location effects resulted in greater tolerance to high temperature and moisture stress. Changes in carbon allocation may be involved in this response. In wet conditions, the root/shoot ratio was 25% greater in translocation lines than control lines. The root/shoot ratio changes in the different lines indicate an alteration in the allocation coefficient. Translocation lines may be useful in studying the effects of ozone on carbohydrate allocation.

K. Burkey (USDA, NC) discussed the contribution of ascorbate to the total apoplastic antioxidant capacity and to O₃ sensitivity in soybean. In the soybean cultivars, Essex and Forrest, apoplastic ascorbate is present at moderate levels but is mostly in the oxidized state and thus not an effective antioxidant. However, the total antioxidant capacity of the apoplast was 2X greater in the tolerant cultivar, Essex, than in the sensitive cultivar, Forrest. At present, the small molecules contributing to the antioxidant capacity are not known. The oxidation state of the extracellular ascorbate pool in soybean correlated with ascorbate oxidase activity.

B. Chevone (VA) discussed the function of a novel F-Box gene (VCF1) that negatively regulates leaf ascorbate content in Arabidopsis and alters ozone sensitivity. Activation-tagged or over-expressing mutants of VCF1 had 50 to 60% less ascorbate than wild-type (wt) plants. These mutants grew slower and were more ozone sensitive than wt plants. T-DNA knockout mutants that had >2X more ascorbate than wt were more ozone tolerant. The F-Box gene is developmentally regulated and expressed least in young leaves and highest in oldest leaves. Ascorbate content was highest in young leaves and lowest in old leaves and this may contribute to the well-documented phenomenon of ozone sensitivity increasing with leaf age. In controlled growth chamber studies on growth media, mutant Arabidopsis, over-expressing the MIOX gene and having 2X more ascorbate, produced 50% more biomass than wt plants. This growth enhancement occurred with both roots and shoots.

H. Sandermann (GSF, Munich) summarized several conceptual aspects of the biochemical processes that determine responsiveness to ozone. In general, ozone inhibits primary metabolism. NADPH oxidase is upregulated by ozone and can lead to cell death and leaf necrosis. There is a time sequence of events with initial propagation and containment transmitted through hormone signals involving SA, JA and ethylene. There also appears to be an ozone memory effect with metabolites lasting over a year. Ethylene is involved in symptom development and if ACC synthase is blocked, no ethylene is produced and no lesions form. ACC can bind to cell walls and stay bound. This can be used as a marker for previous stress, but is not specific to ozone. Ozone also changes the structure of lignin subunits in conifers. The coumaroyl subunit appears to increase and changes lignin structure from conifer to deciduous. The oxidation chemistry of coneflower phenolics, chlorogenic acid and caffeic acid, is unusual in that dihydroxy compounds are formed rather than quinones.

K. Overmyer (NC, UNC) discussed ozone stress and reactive oxygen signaling in Arabidopsis. The ein2 mutant (no ethylene production) is ozone tolerant whereas ethylene biosynthesis results in ozone sensitivity. Mutants with reduced SA signaling have increased ozone tolerance, whereas mutants with no JA signaling are more ozone sensitive. The radical-induced cell death mutant (rcd1) shows foliar injury at an ozone exposure of 100 ppb for 6 h. The rcd1 mutant flowers early and displays premature senescence. It is sensitive to ozone and superoxide, but not to hydrogen peroxide or paraquat. It is ABA insensitive and has reduced sensitivity to ethylene and JA and is involved in programmed cell death. The mutation was mapped to an intron splice site resulting in a truncated protein. RCD1 belongs to the (ADP-ribosyl)transferase domain- containing subfamily of the WWE protein-protein interaction domain protein family. RCSD1 may act as an integrative node in stress hormonal signaling.

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. Attached to this report is a list of attendees and their respective affiliation.

Formally submitted by,

Boris Chevone

Secretary, NE-1013

July 28, 2005

Attendees of the NE1013 Technical Committee Meeting, 2005

Boris Chevone VA

Margaret Pippin NASA Langely

Irene Ladd NASA Langely

Jack Fishman NASA Langely

Kirk Overmyer NC, UNC

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 NY, College Misericordia