Brief Summary of Minutes of Annual Meeting

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. He stated that multi-state projects require impact statements as part of the annual reports for USDA purposes and that a change in the AES administrative advisor position may be forthcoming. 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. Formula funding from Washington should stay level, but NRI funding will be low. The NE 176 termination report will require impact benefits to society. S. Krupa (MN) remarked that target audiences for the project are detailed in the recent Plant Disease article authored by several project members. 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 O3 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

S. Krupa (MN) discussed an approach to modeling ozone exposure-crop response relationships under field conditions, using as an example, alfalfa response to ambient air quality in Alberta, Canada at three study sites over a five-year cycle. A total of 67 harvests (two harvests each year) were used to model alfalfa growth rates and biomass yield in relation to O3, SO2, NOx and various meteorological variables. Growth rates and biomass differed between the harvests, sites and years and were categorized into low or high groups. A multivariate statistical model demonstrated that air quality contributed to 50% of the yield effects and that O3 was the most important air pollutant reducing biomass. W. Manning (MA) presented results on apple seedling, snapbean and bioindicator plant responses to O3 in both open-top chamber (OTC) and ambient air studies. OTCs affected apple seedling growth irrespective of pollutant concentration and, therefore, chambers may be unsuitable for examining O3 effects on some tree species. Snapbean selections R331 (O3 tolerant) and S156 (O3 sensitive) were exposed to ambient O3 for only one harvest period during 2003. Fresh weight of bean pods was reduced by 65% in the sensitive line. Several O3 bioindicator plants were identified including Lyonia ligustrina (purple-reddish coloration on the upper leaf surface), Pinus cembra, a native pine of eastern Europe (chlorotic mottle), N. tabacum Orinoco (small, whitish lesions on upper leaf surface) and garden okra of unknown variety (purple stippling). H. Neufeld (NC, Appalachian State Univ.) discussed research results from both NC and AL (A. Chappelka) on coneflower (Rudbeckia laciniata) response to ambient O3 in the Smoky Mountains National Park. In severely injured leaves, cell wall lignin increased significantly which lowered digestibility by 33% and demonstrated that O3 can affect nutritive quality of plant material. RFLP analysis of coneflowers selected from different sites in the Smoky Mountains Park indicated that at least twenty-three different populations exist in the area. Ozone sensitivities of the different genotypes are not known presently. Physiological studies showed that net photosynthesis in coneflower decreased with increasing foliar O3 injury and with leaf age. In chamber studies, no growth effect from O3 was observed, however, CO2 uptake was reduced in fumigated plants. A. Davison (Univ. of Newcastle, UK) presented results on the use of genetic selection of Brassica rapa in O3 research. B. rapa lines were selected over three generations for differences in acute injury (150 ppb O3), growth in 70 ppb O3 and total leaf ascorbate. Selection of each character resulted in significant differences for that specific character as well as some of the others. Plants sensitive to a high O3 concentration showed foliar injury, reduced growth and lower ascorbate (20%). However, selection for high and low ascorbate resulted in ascorbate differences of 250% between lines, but no effect on visible symptom expression. The experiments demonstrated that B. rapa can be utilized for investigating O3 effects and raises questions concerning the cellular compartmentation and role of ascorbate in influencing the oxidative stress response in plants. B. Momen (MD) discussed the effects of 100 ppb O3 on leaf and stem metabolic heat rate (q) and total dry biomass in tolerant (R331) and sensitive (S156) snapbean cultivars. Cultivar by O3 effect was not significant for stem q, leaf q, and total leaf biomass. However, O3 caused an increase in leaf q in both cultivars indicating decreased metabolic efficiency and/or increased demand for repair and cell maintenance since growth rate was unaffected. A. Bytnerowicz (USDA/FS, CA) presented results from a Sierra Nevada O3 study using passive samplers and visual evaluation of injury to Ponderosa pine at the sampling sites. Ambient O3 concentrations were highly variable on a spatial basis, but less so on a temporal basis. The SW and W portions of the northern Sierras experienced long-term elevated O3 exposures. Ponderosa pines in the Lake Tahoe Basin were slightly injured with 23% of the trees showing foliar O3 symptoms. The Desolation Wilderness creates a barrier that prevents polluted air masses from the California Central Valley and the Bay Area from entering the Lake Tahoe Basin. However, in the southern Sierras, polluted air from the Central Valley crosses the mountains along the Sa Joaquin River drainage causing elevated O3 concentrations in the Mammoth Lakes and Mono Lake areas. K. Burkey (USDA, NC) discussed results from studies with snapbean and apoplastic ascorbate in relation to O3 sensitivity. Tolerant snapbean cultivar (R331) is susceptible to sun scald injury and does show some O3 damage, however, much less than the sensitive cultivar S156. Pod yields in S156, exposed to ambient O3 concentrations, were 70% less than in R331. Apoplastic ascorbate does not seem to relate to O3 sensitivity and other antioxidants, such as ferulic acid, that may be present in the cell wall. In milkweed, cone flower and crownbeard, only apoplastic ascorbate in cone flower correlated with O3 sensitivity. Crownbeard had virtually no cell wall ascorbate. In coneflower, there are numerous antioxidant compounds present in the apoplastic compartment and the concentrations increase in proportion to leaf injury. R. Zaleski (NJ) reported results from a CO2, O3 and drought study using two winter wheat cultivars, Gore (O3 sensitive) and Susquehanna (O3 tolerant) in open-top chambers. Antioxidant enzyme activity was higher in Gore than Susquehanna under control conditions, however, total antioxidants were higher in Susquehanna. Gore was not responsive to O3, whereas ascorbate peroxidase activity and ascorbate increased in Susquehanna. Drought decreased stomatal conductance, but increased glutathione content in both cultivars. The cultivars showed a differential response to the oxidative stresses, with Susquehanna increasing antioxidant activity, but Gore remaining unchanged. B. Chevone (VA) discussed ascorbate biosynthesis in Arabidopsis vtc mutants which are O3 sensitive and have low total ascorbate content compared with wild type plants. Addition of the GLOase gene from rat, which encodes the last enzyme in the animal pathway, into the vtc mutants resulted in rescued ascorbate levels, indicating that more than one biosynthetic pathway exist in plants. Cloning of a myo-inositol oxygenase (MIOX) gene from Arabidopsis and constitutive expression in transgenic plants increased ascorbate content two to fourfold, again demonstrating the existence of more than one route for ascorbate synthesis. An RNAi knockout of all four MIOX genes in Arabidopsis, resulted in arrested growth at the cotyledon stage in transformants, indicating the importance of MIOX to cell wall biosynthesis and ascorbate production. Since some low ascorbate mutants are not O3 sensitive, other biochemical factors must contribute to O3 tolerance. F. Booker (UDSA, NC) reported on the differential responses of G-protein Arabidopsis mutants to O3 exposures. Mutants lacking the alpha subunit of the heterotrimeric G-protein did not display leaf epinasty after O3 treatment. These results are consistent with a role for G-proteins as a signaling link relaying information into the cell from the extracellular site of O3 perception and are critically involved in the expression of O3 effects in plants. Further studies are required to determine if G-proteins have a direct role in O3 signal transduction. H. Sandermann (GSF, Munich) presented conceptual aspects of the O3 dose- response chain-of-events in plants. The internal dose is what is critical and is controlled by the stomata. Ozone can produce an oxidative burst through the NADPH oxidase and generate second messengers such as hydrogen peroxide. Also other genes can be induced, such as stilbene synthase, and compounds produced, such as lipid peroxides, ethylene, and nitrous oxide, that activate defense genes. Therefore, O3 is not generally present at the active site. Ozone induces a metabolic disturbance that generates active oxygen species which, in turn, activate defense systems that result in resistance toward viral, bacterial and fungal pathogens. M. McGrath (NY) summarized results of research conducted since 1998 to assess the impact of ambient O3 on plants growing on Long Island, NY, using sensitive and tolerant snap bean lines. Average reduction in yield of the sensitive line, S156, compared to the tolerant line, R331, was 36% ((31-47%) for weight of pods harvested for fresh-market consumption, 37% (24-59%) for number of pods harvested at maturity, 49% (39-66%) for number of mature seeds, and 27% (21-30%) for mature seed weight. Although ambient ozone concentrations were lower in 2003 than during the previous 8 years, productivity of S156 was reduced comparatively to other years. Application of an insecticide and herbicide were examined to determine if the bean system for assessing ozone impact would be affected. Ozone effect on bean productivity was estimated to be greater for pesticide-treated than non-treated plants: 31% vs 23% reduction in fresh-market yield of S156 compared to R123, 42% vs 21% reduction in number of pods at maturity, and 52% vs 26% reduction in number of seeds at maturity. D. Grantz and A. Shrestha (CA) discussed O3 effects on weed/crop competition and carbohydrate export from photosynthetic tissue. In Pima cotton, O3 reduced growth of fine roots rather than mature roots and could alter water relations and nutrient uptake. Also, O3 affected carbon export from leaf tissue more than net photosynthesis. Ozone decreased the ratio of sucrose to raffinose/stachyose. Since sucrose is apoplastically transported into the phloem tissue, O3 appears to be affecting membrane transport in some manner. In competition studies, O3 affected aboveground growth of cotton more than nightshade, allowing increased nightshade biomass. In tomato/yellow nutsedge competition studies, O3 caused a decrease in tomato height and increased leaf turnover, but decreased root and shoot biomass in both species. Tomato and nutsedge appear to be equally sensitive to O3. In cotton/yellow nutsedge studies, nutsedge outcompeted cotton because cotton in more O3 sensitive.

Booker, FL. 2004. Influence of ozone on ribonuclease activity in wheat (Triticum aestivum L.) leaves. Physiologia Plantarum 120:249-255. Booker, FL, KO Burkey, K Overmyer, AM Jones. 2004. Differential responses of G-protein Arabidopsis thaliana mutants to ozone. New Phytologist 162:633-641 Booker, FL, EL Fiscus, JE Miller. 2004. Combined effects of elevated atmospheric carbon dioxide and ozone on soybean whole-plant water use. Environmental Management 33:S355-S362. Bytnerowicz, A, B Godzik, K Grodzinska, W Frczek, R Musselman, W Manning, O Badea, F Popescu, P Fleischer. 2004. Ambient ozone in forests of the Central and Eastern European mountains. Environmental Pollution 130: 5-16. Estes, BL, SA Enebak, AH Chappelka. 2004. Loblolly pine seedling growth after inoculation with plant growth-promoting rhizobacteria and ozone exposure. Canadian Journal of Forest Research 34:1410-1416. Finkelstein, PL, AW Davison, HS Neufeld, TP Meyers, AH Chappelka. 2004. Sub-canopy deposition of ozone in a stand of cutleaf coneflower. Environmental Pollution 131:295-303. Grantz, DA and MJ Sanz. 2004. Common co-occurrence of citriculture and ozone air pollution: Potential for yield reductions. Proceedings 10th International Society of Citriculture Congress. Paper No. 97. Grantz, DA and AK Murray. 2004. Effect of ozone on phloem transport in cotton. Proceedings of the 2004 Beltwide Cotton Conferences, San Antonio, TX. January 2004. Pp. 2144-2149. Grantz, DA and A Shrestha. 2004. Ozone affects competition between cotton and nutsedge. Proceedings of the 2004 Beltwide Cotton Conferences, San Antonio, TX. January 2004. Pp. 2877-2882. Gravano, E, F Bussotti, RJ Strasser, M Schaub, K Novak, JM Skelly, C Tani. 2004. Ozone symptoms in leaves of woody plants in open-top chambers: ultrastructural and physiological characteristics. Physiologia Plantarum 121:620-633. Grünhage, L, SV Krupa, AH Legge, HJ Jäger. 2004. Ambient flux-based critical values of ozone for protecting vegetation: differing spatial scales and uncertainties in risk assessment. Atmospheric Environment 38:2433-2437. Krupa, SV, R Muntifering, AH Chappelka. 2004. Effects of ozone on plant nutritive quality characteristics for ruminant animals. The Botanica 54:1-12. Long SP, EA Ainsworth, A Rogers, DR Ort. 2004. Rising atmospheric carbon dioxide: plants FACE the future. Annual Review of Plant Biology 55:591-628. Lorence, A, BI Chevone, P Mendes, CL Nessler. 2004. Myo-inositol oxygenase offers a possible entry point into plant ascorbate biosynthesis. Plant Physiology 134:1200-1205. Manning, WJ, CJ Bergweiler. 2004. Assessing plant response to ambient ozone: growth of young apple trees in open-top chambers and corresponding ambient air plots. Environmental Pollution 132:503-508. Manning, WJ, B Godzik. 2004. Bioindicator plants for ambient ozone in Central and Eastern Europe. Environmental Pollution 130:33-39. Morgan PB, CJ Bernacchi, DR Ort, SP Long. 2004. An in vivo analysis of the effect of season-long open-air elevation of ozone to anticipated 2050 levels on photosynthesis in soybean. Plant Physiology 135:2348-2357. Murray, AK and DA Grantz. 2004. Carbohydrate composition of cotton aphid honeydew. Proceedings of the 2004 Beltwide Cotton Conferences, San Antonio, TX. January 2004. Pp. 1590-1593. Niyogi, D, H-I Chang, VK Saxena, T Holt, K Alapaty, FL Booker, F Chen, KJ Davis, B Holben, T Matsui, T Meyers, WC Oechel, RA Pielke, Sr, R Wells, K Wilson, Y Xue. 2004. Direct observations of the effects of aerosol loading on net ecosystem CO2 exchanges over different landscapes. Geophysical Research Letters 31: L20506, doi: 10.1029/2004GL020915. Robinson, JM, J Lydon, CA Murphy, R Rowland, R Smith. 2004. Effect of Pseudomonas syringae pv. tagetis infection on sunflower leaf photosynthesis and ascorbic acid relations. International Journal of Plant Science. 165:263-271. Robinson, JM, RC Sicher Jr. 2004. Antioxidant levels decline in primary leaves of barley during growth at ambient and elevated carbon dioxide levels. International Journal Of Plant Science. 165:965-972. Sandermann, H. (ed). 2004. Molecular Ecotoxicology of Plants. Berlin: Springer. 241 pp. Sanz, J, RB Muntifering, BS Gimeno, V Bermejo. 2004. Nutritive quality and growth of Trifolium subterrraneum are modulated by ambient ozone concentrations and nitrogen fertilization. In: Garcia Criado, B, Garcia Cuidad, B, Vasquez de Aldana, A, Zabagogeazcoa, I. (eds.). Proceedings Spanish Society for Pasture Studies, Salamanca, Spain. 10-14 May. Pp. 197-201. Schaub, M, JM Skelly, KC Steiner, DD Davis, SP Pennypacker, J.Zhang, JA Ferdinand, JE Savage, RE Stevenson. 2004. Physiological and foliar responses of Prunum serotina, Fraxinus americana and Acer rubrum seedlings to varying soil moisture and ozone. Environmental Pollution 124:307-320. Skelly JM, DD Davis, DR Decoteau. 2004. Development of an air quality learning and demonstration center at the arboretum at Penn State. HortScience 39:810. Wei, C, JM Skelly, SP Pennypacker, JA Ferdinand, JE Savage, RE Stevenson, DD Davis. 2004. Responses of hybrid poplar clones and red maple seedlings to ambient ozone under differing light within a mixed hardwood forest. Environmental Pollution 130:199-214. Wei, C, JM Skelly, SP Pennypacker, JA Ferdinand, JE Savage, RE Stevenson, DD Davis. 2004. Influence of light fleck and low light on foliar injury and physiological responses of two hybrid poplar clones to ozone. Environmental Pollution 130:215-227.