Annual/Termination Reports:

[02/18/2014]

Report Information

Participants

Those attending in person were Chappelka, Art (chappah@auburn.edu)  Auburn University; Muntifering, Russ (muntirb@auburn.edu)  Auburn University; Calvete-Sogo, Hector (hector.calvete@ciemat.es)  CIEMAT/Auburn University; Wiese, Cosima (cwiese@misericordia.edu)  Misericordia University; Minocha, Subhash (sminocha@unh.edu)  University of New Hampshire; Burkey, Kent (Kent.Burkey@ars.usda.gov)  USDA-ARS .

Those attending for portions of the meeting via conference call were Grantz, David (dagrantz@ucanr.edu)  University of California, Riverside; Nancy Grulke (ngrulke@fs.fed.us)  USFS; Margaret Smith (mes25@cornell.edu )  Cornell University; Raymond Knighton (Rknighton@nifa.usda.gov) - NIFA.

Brief Summary of Minutes

Research reports were presented by Chappelka, Calvette-Sogo, Muntifering, Wiese, Burkey, and Minocha with follow-up discussion. Details are incorporated into the accomplishments section of this report.

A major topic of discussion was the question of continuing as a coordinating committee or returning a research committee organization. Many research stations do not provide travel funding to attend coordinating committee meetings, and as a result participation in this NECC-1013 Coordinating Committee has declined relative to the former NE-1030 Multi-state Research Committee. This reality makes the long-term viability a concern for this group. Being able to meet in person periodically is important to many of those currently involved in the committee. There was a general consensus of members participating in the discussion to return to the research format with two considerations: (1) increase membership by expanding the scope of a new project to include other pollutants or abiotic stressors in addition to ozone, perhaps under the umbrella of climate change, and (2) limit the number of objectives of the new project to perhaps one research objective and one outreach objective. The challenge will be to develop a single research objective that allows broad participation but provides specificity for establishing a group identity and allow formation of sub-groups to conduct specific studies. One potential research objective discussed was the concept of biomarkers for abiotic stress that might provide a common theme to allow participation of scientists from diverse disciplines (e.g. ecology, genetics, physiology, biochemistry) and ecosystems (e.g. agriculture, forests, National Parks) in a single research committee.

Margaret Smith (our Administrative Advisor) and Ray Knighton (our NIFA representative) both indicated that there should be no problem with transitioning back to a research committee before the end of the 5-year period of NECC-1013 if the group wishes to do this. Margaret Smith suggested that the current coordinating committee structure could be used as a framework to organize and write the proposal for a new research committee. Establishing a new Multi-state Research Project will require approximately 2 years. The process begins with a request to write a proposal (justification, why does group want to do this, etc.) to the Directors of a particular region (e.g. Northeast)  the earliest this could be done is the Directors spring meeting of 2014. If the request is approved, a formal project proposal would then be written and considered by the Directors of the region. The most rapid scenario would involve submission of the proposal for review by the fall of 2014, consideration by the Directors in the spring/summer of 2015, and final approval in late 2015.

Ray Knighton suggested the group also examine existing committees to determine whether other groups with common interests already exist. Following the meeting, a survey of projects in NIMSS did not reveal established groups with common interests in air pollution and/or climate change effects on vegetation. Thus, a project developed around assessing/adapting plant response to climate change may be unique and attract a large group of scientists that currently do not have a home in a Multi-state Experiment Station project.

Accomplishments

Effect of pH on Photosynthesis in the Aquatic Plant Duckweed (Lemna spp.). Acid precipitation and acid mine drainage is known to change the pH of aquatic ecosystems, and may be acting as a stressor to aquatic plants. This study investigated the effect of an altered environmental pH on the aquatic plant duckweed Lemna minor. L. minor plants were grown in aerated flasks with a modified Hoaglands solution in an environmental chamber with a 16 hr photoperiod for 14 days. Three replicate samples were allowed to grow in each of three pH levels: pH 4, pH 5.3, and pH 6.5. Reduced biomass, growth rate, and leaf color was observed in pH 4 solutions as compared to pH 5.3 and pH6.5. Further experimentation to assess plant metabolism encompassed investigation of photosynthetic capacity by quantification of products necessary for successful photosynthesis, including chlorophyll a, chlorophyll b, and Rubisco. The quantity of chlorophyll b was significantly reduced in plants grown in pH 4 as compared to controls; changes in Rubisco quantity as a result of exposure to acidic pH are still being investigated. The impacts on chlorophyll quantity are being further analyzed by determining whether changes in gene expression of chlorophyll synthase, the enzyme which catalyzes the final step in chlorophyll a synthesis, may contribute to decreases in total chlorophyll. Additional work is also underway to evaluate whether exposure to acidic conditions increases oxidative stress in the plant, which would result in negative impacts on plant growth and reproduction. [Misericordia University]<br /> <br /> Effect of elevated tropospheric ozone (O3) and atmospheric nitrogen (N) deposition on productivity and nutritive quality of a semi-natural, species-rich, grassland community. An experiment was conducted near Madrid, Spain in the autonomous community of Castile-La Mancha, Province of Toledo, that comprised 15 open-top chambers (OTC) for controlled fumigation with O3 concentrations to simulate a full range of air-quality scenarios from pristine to polluted. From mid-April through mid-June 2012, the following O3 treatments were applied to mesocosms of a grassland community: charcoal-filtered air (CFA), non-filtered ambient air (NFA), or NFA supplemented with 25, 40 or 55 nl·l-1 O3 from 7:00 a.m. to 5:00 p.m. daily (3 OTC or main plots/air treatment); sub-plots within each OTC received applications of different doses of NH4NO3 solution every 15 days to achieve cumulative deposition by the end of the growing season of 0, 10, 30 or 60 kg N·ha-1. Plant material was harvested in early May and again in mid-June in during the 2013 growing season. Sixty forage samples (5 air treatments × 4 N treatments × 3 OTC) were taken by destructive harvest at each time. Samples are undergoing analysis for foliar concentrations of dry matter and N according to AOAC (1995); total cell-wall constituents (cellulose, hemicellulose and lignin) according to Van Soest et al. (1991); and in vitro digestibility according to Van Soest et al. (1991). Nitrogen deposition and O3 exposure effects on nutritive quality parameters will be evaluated by two-way ANOVA, and significant (P < 0.05) differences among treatments by Tukeys honest significant-difference test. [Auburn University]<br /> <br /> Effects of ozone on loblolly pine decline. The hypothesis is exposure to changing climatic conditions including increases in water deficit and concentrations of ozone weakens Pinus taeda seedlings and exacerbates loblolly pine decline by reducing tree vigor and increasing susceptibility to colonization by Leptographium terebrantis and/or Grosmannia huntii, causal agents associated with this disease complex. To accomplish this goal 9 large (4.8 m height × 4.5 m diameter) OTCs were used in 2013. Two experiments will be conducted: In 2013, four loblolly families (2 tolerant and 2 susceptible) infected with two fungal associates of the decline will be exposed to three ozone treatments [carbon-filtered, non-filtered (NF, ambient) and 2.0 × NF] replicated three times for 3 (with fungus)-4 months (total). In addition, a plate study was designed to examine the effects of varying ozone concentrations directly on the growth of fungi associated with loblolly pine decline. The fungi used included Leptographium terebrantis, L. procerum, G. huntii and G. alacris. The study was terminated in September and the data are currently being analyzed. [Auburn University]<br /> <br /> Effects of climate change on wheat-rust interactions. Four wheat varieties with different levels of susceptibility/resistance to wheat leaf rust, Puccinia triticina, were vernalized and grown under combinations of elevated carbon dioxide and ozone in our outdoor plant environment chambers. Optimized temperature and relative humidity conditions provided conditions to facilitate pathogen infection and development on plants. Disease latency and intensity, foliar symptoms caused by both ozone and pathogen infection, biomass, seed yield and seed quality were measured. Preliminary assessment of the data suggests there are significant interactions between genotype, gas treatment, and pathogen infection. [USDA-ARS at North Carolina State University]<br /> <br /> Technology for studying elevated temperature effects in field plots. Additional improvements were made in our Air Exclusion System (AES), an exposure system designed to provide a clean-air (charcoal-filtered) environment along with elevated temperature, ozone and CO2 treatments in field plots. The original passive solar heating units were replaced with additional water-to-air solar heat exchangers so that each heated plot now has a total of four heat exchangers in addition to the electrical resistance heating system. Experience to date suggests that the current design will provide an elevated temperature treatment of 3.5 to 4.5 degrees Celsius above ambient conditions. Replacement of the passive solar units significantly reduced the foot print of each plot so that the field can now accommodate additional experimental plots. AES heated plots are being compared with AES controls and ambient air plots in a replicated soybean study in 2013. The irrigation approach will target common soil moisture content across all plots, replacing simulated uniform rainfall events, to compensate for greater water usage in heated plots and reduce confounding effects of temperature and drought. Harvest and environmental data are being collected for use in a crop growth computer model. [USDA-ARS at North Carolina State University]<br /> <br /> Mapping ozone tolerance genes in soybean. A population of 240 recombinant inbred lines derived from a cross between Fiskeby III (ozone-tolerant) and Mandarin Ottawa (ozone-sensitive) genotypes was advanced. Single nucleotide polymorphism DNA markers were used to construct the linkage map. Data from screening of the population for ozone-induced foliar injury were finalized and formatted quantitative trait loci (QTL) analysis. Mapping software was used to identify QTLs for ozone response on several chromosomes. [USDA-ARS at North Carolina State University]<br /> <br /> Diurnal cycles regulating plant responses to ozone. Inherent plant defense capacity against O3 stress was shown to vary diurnally, and the mechanism explored using Pima cotton, cv. S-6, grown in a greenhouse. Injury was determined from digital photo analysis of necrosis, chlorophyll content and summed abaxial and adaxial stomatal conductance 6-7 days after exposure. Leaves were most sensitive near 3:00 p.m. in repeated experiments. Antioxidant levels of foliar ascorbic acid and of total foliar antioxidant capacity exhibited a moderate peak near midday, but leaf injury was also greatest at this time. Regression relationships between sensitivity to O3 injury and various measures of antioxidant status were not significant. While the diurnal nature of O3 sensitivity is confirmed, the mechanism remains to be elucidated. These data indicate that parameterization of models of O3 injury to vegetation will require measures of inherent defense capability, for which time of day may be a key determinant. [University of California  Riverside; USDA-ARS at North Carolina State University]<br /> <br /> Ambient ozone does not contribute to perchlorate accumulation in plants. Perchlorate in the environment is toxic to human health and is now detected across large areas, particularly in arid regions. Although potential sources include rocket fuel, fireworks, highway flares, and Chilean nitrate fertilizer, perchlorate is now showing up in areas that cannot be attributed to these sources. It has been suggested that plants growing in O3 polluted atmospheres may be a source of de novo synthesis of perchlorate. Ten species of plants were grown in Greenhouse CSTRs and exposed to O3. The average for all ten species measured, suggested that there was no O3 effect on foliar perchlorate levels of daily fumigation over a range of 0 to 120 ppb, 12 hour mean. There were substantial differences in perchlorate accumulation among plants, the source being the fertilizer used to provide nutrients for plant growth. Sugarcane consistently accumulated perchlorate to less than 100 µg/g, whereas broccoli and cotton accumulated between 350-675 µg/g, and spinach accumulated over 675 µg/g, representing differences in uptake or exclusion from the rhizosphere. There is no robust relationship between foliar perchlorate and O3 exposure of a magnitude that could contribute meaningfully to the widespread environmental contamination by perchlorate observed. [University of California  Riverside; USDA-ARS at North Carolina State University]<br /> <br /> Ailanthus altissima as an ozone bio-indicator plant. A series of greenhouse exposures and field studies were conducted to evaluate the usefulness of Ailanthus altissima to function as a bioindicator plant species for detecting phytotoxic levels of ambient ground-level ozone in rural areas. Ailanthus seedlings that originated from seed collected near Corvallis, Oregon (OR) were significantly more susceptible to ozone than seedlings from other seed sources, and symptom severity was directly related to concentration and duration of ozone exposure. In the field, Ailanthus seedlings from the OR seed source were out-planted in central Pennsylvania where they developed ozone-induced foliar symptoms from low levels of ambient ozone. Results of this study should help clarify exposure/response relationships between ambient ozone levels and foliar symptoms on Ailanthus, as well as provide useful data for setting the National Ambient Air Quality Standard (NAAQS) for ozone. [Penn State University]<br /> <br /> Characterization of molecular basis of O3-tolerance/-sensitivity in forest tree species. For the past 4 years, leaf tissue of control and ozone-treated seedlings of black cherry (Prunus Serotina), northern red oak (Quercus rubra L.), black walnut (Juglans nigra), green ash (Fraxinus pennsylvanica), Tulip poplar (Liriodendron tulipifera L. ), and Black gum (Nyssa sylvatica) was collected for RNA extraction and cDNA library preparation and sequencing. After genome assembly and annotation we found that 12-13% of the EST sequences were from genes known to be involved in response to biotic and abiotic stresses (with almost no difference among species). Expression of stress-response genes was generally up-regulated, while more genes in the mitochondria were down-regulated than up-regulated. Genes encoding for heat shock proteins were mostly up-regulated; these genes are also known to be involved in drought and cold tolerance. Expression of salt-responsive genes was found to be up-regulated while regulatory factors involved in stomatal closure were down-regulated. Transcription factors involved in leaf senescence were up-regulated in more sensitive species (black cherry, black walnut, green ash, and tulip poplar) and down-regulated in Northern red oak and Black gum which were more tolerant species (e.g. at the end of treatment did not show visible injury). The comparative hardwoods transcriptome analysis indicates that ozone stress triggers pathways that are similar to those triggered by other known abiotic stressors. [Penn State University]

Publications

Grantz, D.A., H.-B. Vu, R.L. Heath, and K.O. Burkey (2013) Demonstration of a diel trend in sensitivity of Gossypium to ozone: a step toward relating O3 injury to exposure or flux. Journal of Experimental Botany. 64: 1703-1713.<br /> <br /> Calvete-Sogo, H., V. Bermejo, L. Sanchez, R. Muntifering, J. Sanz, S. Elvira, I. Gonzalez-Fernandez, A. Vallejo and R. Alonso. 2013. Ozone and nitrogen effects on the annual understory vegetation of open holm oak forests. IUFRO meeting (Vegetation Response to Climate Change and Air Pollution - Unifying Evidence and Research across Northern and Southern Hemisphere), Ilhéus, Bahia, Brazil, September 1-6.

Impact Statements

1. Research at Auburn University to understand the combined effects of elevated O3 and N deposition on productivity and nutritive quality of grazinglands will assist policymakers and resource managers concerned with forage-based production systems.
2. Climate change is expected to affect plant-pathogen interactions, but the nature and magnitude of these effects are not known. Research by members of NECC-1013 to understand climate change effects on wheat-rust (USDA-ARS, Raleigh) and loblolly pine-fungus (Auburn University) interactions are specific examples of the information needed to evaluate the potential impact of climate change on plant diseases and develop management strategies for dealing with the problems that arise.
3. Adaptation of agricultural and commercial forest species to air pollution and climate change can take advantage of modern breeding and genetics approaches, but requires an understanding of the mechanisms controlling plant response as a step toward identifying genes of interest and developing screening protocols. Research on the physiological and molecular basis of ozone tolerance is being conducted on multiple species by NECC-1013 members.
4. The Air Quality Learning and Demonstration center at Penn State provided hands on learning experiences for classes at Penn State and the general public around Centre County in Pennsylvania. During 2013 approximately 200 individuals attended course lectures or public presentations on air pollution effects on terrestrial plants at the Learning Center.
5. The USDA-ARS Air Quality program demonstrated ozone injury assessment for soybeans as part of the annual Southern Soybean Breeders Tour held in Raleigh, NC during 2013. NC. The 2-day event brought together approximately 150 participants from public and private breeding programs across the Southern USA.
6. Ozone-sensitive and -tolerant snap beans developed by USDA-ARS in Raleigh, NC were used in ozone gardens at Harvard University, the St. Louis Science Center and two other locations in St. Louis, and the Goddard Science Center, Greenbelt, MD. The snap beans were also grown by a University of IL, Urbana-Champaign graduate students urban agriculture project in Chicago and are being tested as an ozone bio-indicator system at a number of locations in Europe and Asia by the ICP-Vegetation program.

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