2005 Annual Report 1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? General circulation models predict temperature rises of 1.4-5.8°C by 2100, associated with carbon dioxide increases to 540-970 parts per million. Doubling CO2 increases C3 seed yields by ~33%. But previous research at Gainesville showed that increasing temperatures 10°C above optimum decreased seed yield to zero, a decline of 10% per 1°C. Yield declines are always related to pollination failures and sometimes to partial seed-fill failure. Thus, the major problem or issue is the serious negative impact that projected global warming would have on productivity and yield of seed crops that provide food for humans and feed for animals. We will seek to resolve this problem in three ways. Specifically, we will (a) search for and identify cultivars of selected crops (especially soybean and grain sorghum) that demonstrate high temperature tolerance via adaptations in pollen development or fertilization processes (tolerance), or in early time-of-day of flowering (avoidance); (b) determine if starch metabolism failures in pollen development contribute to reproductive failures of grain sorghum and maize under high temperatures and if heat tolerance is mediated through altered control of gene expression in the sucrose ¿ starch pathway that leads to starch-deficient pollen and pollen abortion; (c) determine if reproductive failures under high temperatures are mediated or exacerbated by low internal oxygen concentration in reproductive tissues. The progressive failure of seed yield with increasing temperature could be a serious threat to food availability and security, and we should determine how serious the matter is now, and if there genetic traits available to alleviate the problems in the future. We will cooperate with the University of Florida and the ARS Phytonutrients Laboratory in Beltsville to determine treatment effects on viability and nutritive value of seeds. We will collaborate with ARS Environmental and Plant Dynamics Research in Phoenix on development of improved components of crop models. Another major problem or issue is that certain specialized photosynthetic pathway plants have shown moderate but unexpected responses to elevated carbon dioxide and temperature. We will search for the reason behind these moderate responses by measuring photosynthetic and sucrose metabolism enzyme amounts and activities in various stages of leaf development in grain sorghum and maize. Since cereal grain crops such as maize and grain sorghum are among the worlds most important crops, we need to understand how they might respond positively to rising carbon dioxide. The above studies will be conducted in specialized controlled-environment plant growth chambers located outdoors in natural sunlight or in computer-controlled temperature-gradient greenhouses. This research is directly related to the Global Change National Program 204 and to Strategic Planning Codes 1.1.1.1 and 1.1.2.1. Research on grain sorghum and maize photosynthetic acclimation to elevated CO2 and temperature, and reproductive and seed yield responses of soybean, grain sorghum, maize, and dry bean to high temperature and elevated CO2 support the program component "Global Change Effects on Plants and Ecosystem Processes.” The research falls under National Programs 204 (Global Change) and 305 (Crop Production), and addresses Problem Areas and Goals as described in the National Program Action Plan. Specifically, these are: The Cropping Systems Problem Area of Component III: Agricultural Ecosystems Impacts of NP204 (Global Change), and the Sustainable Cropping Systems Problem Area of Component I: Integrated Cropping Systems of NP305 (Crop Production). In addition, this research addresses the following policy-relevant science questions in the Strategic Plan for the U.S. Climate Change Science Program (2003; http://www.climatescience.gov/Library/stratplan2003/default.htm). Question 8.2: What are the potential consequences of global change for ecological systems? Question 8.3: What are the options for sustaining and improving ecological systems and related goods and services, given projected global changes? 2.List the milestones (indicators of progress) from your Project Plan. Milestones for the new project are listed below as extracted from the Project Plan approved by OSQR and initiated January 20, 2005. Milestones Year 1 (FY 2005) 1.Complete experiment for evaluating 20 selected soybean cultivar responses to elevated temperature and CO2 in Temperature-Gradient Greenhouses. 2.Evaluate new Infrared Heaters in Soil-Plant-Atmosphere Research chambers for future use in establishing temperature treatments in open field Free-Air CO2 Enrichments systems. 3.Determine physiological and genetic control factors on grain sorghum and maize pollen fertility at controlled elevated temperatures of plants grown in Soil-Plant-Atmosphere Research units. 4.Procure and evaluate microprobe oxygen sensors for use on reproductive tissues and developing crop seeds. 5.Prepare and send samples of final harvest seeds to the Phytonutrients Laboratory collaborators in Beltsville for analyses of elevated temperature and CO2 impacts on specific nutritional factors. 6.Prepare samples of final harvest seeds for University of Florida collaborators for analyses of elevated temperature and CO2 impacts on seed quality and germination/emergence capabilities. 7.Consult and share data with collaborators (ARS in Phoenix and University of Florida) on crop model development for improved prediction of crop response to elevated temperature and CO2. 8.Test hypothesis that the unanticipated increase of plant biomass of C4 photosynthetic pathway plants in response to elevated CO2 is controlled by improved photosynthetic rates of leaves at specific stages of development due to changes in activities and amounts of various photosynthetic enzymes and sucrose metabolism enzymes. Year 2 (FY 2006) 1.Evaluate pollination and seed yield tolerance of 20 selected soybean cultivars to impacts of elevated temperatures and CO2. 2.Complete experiment for evaluating sorghum and maize cultivar responses to elevated temperature and CO2 in Temperature-Gradient Greenhouses. 3.Analyze foliage temperatures and evapotranspiration data obtained in use of a new Infrared Heaters technology for use in temperature treatment studies in open field Free-Air CO2 Enrichments systems. 4.Repeat for second year and revise if necessary the determination of physiological and genetic control factors on grain sorghum and maize pollen fertility at controlled elevated temperatures of plants grown in Soil-Plant-Atmosphere Research chambers. 5.Recondition Soil-Plant-Atmosphere Research chamber system for controlled levels of oxygen concentration. Confirm function with preliminary crop. 6.Continue preparation and sending seeds to the Phytonutrients Laboratory collaborators in Beltsville for analyses of elevated temperature and CO2 impacts on specific nutritional factors. 7.Continue preparation of seeds for University of Florida collaborators for analyses of impacts of elevated temperatures and CO2 on seed quality and germination/emergence capabilities. 8.Continue consultation and sharing data with collaborators (ARS in Phoenix and University of Florida) on crop model development for improved prediction of crop responses to elevated temperatures and CO2. 9.Repeat and reconfirm (and adjust if necessary) experiments of testing the hypothesis that the unanticipated increase of plant biomass of C4 photosynthetic pathway plants in response to elevated CO2 is controlled by improved photosynthetic rates of leaves at specific stages of development due to changes in activities and amounts of various photosynthetic enzymes and sucrose metabolism enzymes. Year 3 (FY 2007) 1.Prepare and submit manuscript(s) that report the range of tolerance of 20 selected cultivars of soybean seed yields to impacts of elevated temperatures and CO2, and interpret options for amelioration in f ace of potential global climate change. Share data with collaborators for improving crop simulation models. 2.Evaluate pollination and seed yield tolerance of 20 selected sorghum and maize cultivars to impacts of elevated temperatures and CO2. 3.Evaluate hypothesis of limiting sugar-starch metabolism at high temperatures on control of physiological and genetic factors on grain sorghum and maize pollen fertility of plants grown at controlled elevated temperatures. 4.Conduct study of impact of temperature and ambient oxygen concentration on the pO2 of developing reproductive tissues and developing seeds of soybean and dry bean grown in a range of temperatures at two oxygen concentration (21 and 32 kPa) for examining the hypothesis that elevated temperatures lead to oxygen limitations because of lowered oxygen solubility and increased respiratory oxygen demand. 5.Continue preparation and sending seeds to the Phytonutrients Laboratory collaborators in Beltsville for analyses of elevated temperature and CO2 impacts on specific nutritional factors. 6.Continue preparation of seeds for University of Florida collaborators for analyses of impacts of elevated temperatures and CO2 on seed quality and germination/emergence capabilities. 7.Continue consultation and sharing data with collaborators (ARS in Phoenix and University of Florida) on crop model development for improved prediction of crop responses to elevated temperatures and CO2. 8.Prepare and submit manuscript(s) reporting plant biomass, photosynthetic rates, and changes in activities and amounts of various photosynthetic enzymes and sucrose metabolism enzymes of C4 photosynthetic pathway plants in response to elevated CO2. Support or deny the hypothesis that conditions at specific stages of leaf development provide the unanticipated boost of response to elevated CO2. 9.Characterize the photosynthetic mechanisms of the leaf stage(s) that respond to elevated CO2. 10.Assess carbohydrate metabolism efficiency in C4 plants. Year 4 (FY 2008) 1.Prepare and submit manuscript(s) that report the range of tolerance of selected cultivars of grain sorghum and maize seed yields to impacts of elevated temperatures and CO2, and interpret options for adapting or amelioration using heat-tolerant cultivars in face of potential global climate change. Share data with collaborators for improving crop simulation models. 2.Prepare and submit manuscript(s) evaluating the hypothesis of limiting sugar-starch metabolism at high temperatures on control of physiological and genetic factors on grain sorghum and maize pollen fertility of plants grown at controlled elevated temperatures. 3.Conduct second study of impact of temperature and ambient oxygen concentration on the pO2 of reproductive tissues and developing seeds of soybean and dry bean grown in a range of temperatures at two oxygen concentration (21 and 32 kPa) for examining the hypothesis that elevated temperatures lead to oxygen limitations because of lowered oxygen solubility and increased respiratory oxygen demand. 4.Evaluate impacts of elevated temperatures and CO2 on specific nutritional factors of seeds by the Phytonutrients Laboratory collaborators in Beltsville. 5.Analyzed data and evaluate impacts of elevated temperatures and CO2 on seed quality and germination/emergence capabilities of final harvest seeds by University of Florida collaborators. 6.Evaluate improved crop model capabilities for predicting plant growth and yield responses of current and heat-tolerant cultivars to future anticipated climate conditions by collaborators (ARS in Phoenix and University of Florida). 7.Prepare and submit manuscript(s) reporting the characteristics of the photosynthetic mechanisms of the leaf stage(s) that respond to elevated CO2. 8.Prepare and submit manuscript(s) reporting carbohydrate metabolism efficiency in C4 plants. Year 5 (FY 2009) 1.Prepare and submit manuscript(s) reporting results of the hypothesis that elevated temperatures lead to oxygen limitations because of lowered oxygen solubility and increased respiratory oxygen demand. Develop recommendations for research on physiological or genetic mechanism to overcome the high temperature-induced oxygen limitations to growth and development of reproductive tissues and seeds. 2.Prepare and submit manuscript(s) quantifying impacts of elevated temperatures and CO2 on specific nutritional factors of seeds, led by the Phytonutrients Laboratory collaborators in Beltsville. 3.Prepare and submit manuscript(s) quantifying impacts of elevated temperatures and CO2 on seed quality and germination/emergence capabilities of seeds, led by University of Florida collaborators. 4.Prepare and submit manuscript(s) quantifying improved crop model capabilities for predicting plant growth and yield responses of current and heat-tolerant cultivars to future anticipated climate conditions, led by collaborators (ARS in Phoenix and University of Florida). Expand evaluations of food production potentials in scenarios of global environmental changes. 5.Prepare and submit manuscript(s) on all aspects of positive responses of C4 plants to rising CO2 and temperature. 4a.What was the single most significant accomplishment this past year? Enhancement in leaf photosynthesis of the C4 grain sorghum plant under elevated growth CO2 and temperature occurs at early stages of leaf development. Grain sorghum plants were grown under ambient and double-ambient (elevated) CO2 and at daytime maximum/nighttime minimum temperatures of 30/20 Celsius (low temperature) or 36/26 Celsius (high temperature), and the photosynthetic rates and activities of the two key photosynthetic enzymes in C4 plants were measured (Rubisco and PEPC) at various stages during leaf growth and development. The purpose was to determine if there was a certain growth stage of the leaf during which photosynthetic activities were stimulated by elevated growth CO2 and high temperature. The results demonstrate that photosynthetic rates of young leaves were enhanced by elevated CO2 at both low and high temperature regimes. From 6 to 25 days after leaf emergence, photosynthetic rates of the high-CO2 plants were 10 to 24% greater at both low and high temperatures. In addition, photosynthetic rates of the top (younger) leaves were more responsive to elevated CO2 than the lower (older) leaves. Elevated CO2 also enhanced Rubisco activity in the young leaves. From 6 to 12 days after leaf emergence, high CO2 enhanced Rubisco up to 24% at low temperature and 43% at high temperature. The PEPC enzyme activity was not affected by elevated CO2 at low temperature, but was enhanced by 12% at high temperature during the 6 to 12 day after leaf emergence period. Various plant biomass parameters, determined at 50 days after seed planting, were enhanced by elevated CO2 up to 49% at low temperature and 62% at high temperature. Thus, for grain sorghum, there was enhancement in leaf photosynthetic and Rubisco by elevated CO2, or by elevated CO2-high temperature combination, at early leaf growth stages. This information about stimulation in photosynthetic activities in young leaves and subsequent biomass increases explains the unexpected responses for this C4 crop species under elevated growth CO2 and temperature (which is somewhat similar to sugarcane responses). 4b.List other significant accomplishments, if any. None. 4c.List any significant activities that support special target populations. None. 4d.Progress report. No report. 5.Describe the major accomplishments over the life of the project, including their predicted or actual impact. This project was initiate January 20, 2005, so no other new major accomplishments are available. A number of other major accomplishments may be found in earlier reports for the preceding project 11000-006-00D. 6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Information has been transferred to other scientists and policy-makers that are concerned about plant responses to global climate change that may be induced by rising greenhouse effect gases. Within the next 2 to 3 years, we should be able to provide criteria to plant breeders for selection of high temperature tolerance in seed crops. Constraints on adoption of technology is probably the rate of increase of global warming or other climate changes. 7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Presentations. Alagarswamy, G., Boote, K.J., Jones, J.W., Allen, L.H., DuToit, A.S. Evaluation of the ability of the CROPGRO-soybean model to simulate growth and yield responses to [CO2]. American Society of Agronomy 96th Annual Meeting, Seattle WA, October 31-November 4, 2004. Abstract. Allen, L.H., Albrecht, S.L., Boote, K.J., Thomas, J.M.G., Skirvin, K. Soil carbon and nitrogen sequestration potential of rhizoma perennial peanut and bahiagrass grown in elevated CO2 and temperature. American Society of Agronomy 96th Annual Meeting, Seattle WA, October 31-November 4, 2004. Abstract. Prasad, P.V.V., Boote, K.J., Allen, L.H. Impact of elevated temperature and CO2 on growth, reproductive processes, and yield of grain sorghum. American Society of Agronomy 96th Annual Meeting, Seattle WA, October 31-November 4, 2004. Abstract. Allen, L.H., Albrecht, S.L., Boote, K.J., Thomas, J.M.G., Skirvin, K., Nelson, S.D. Soil Organic Carbon and Nitrogen Accumulation of Rhizoma Perennial Peanut and Bahiagrass Grown under Elevated CO2 and Temperature. USDA Greenhouse Gas Symposium, Baltimore, MD. March 21-24, 2005. Abstract. Allen, L.H., Albrecht, S.L., Boote, K.J., Thomas, J.M.G., Skirvin, K. Soil carbon and nitrogen accumulation of rhizoma perennial peanut and bahiagrass forage crops grown in elevated CO2 and temperature. The 16th Global Warming International Conference & Expo, New York, NY, April 19-21, 2005. Abstract. Allen, L.H., Boote, K.J., Prasad, P.V.V, Baker, J.T., Gesch, R.W., Snyder, A.M., Pan, D., Thomas, J.M.G., Vu, J.C.V. Food security and agriculture: Impacts of elevated temperature and CO2 on pollination and yield of globally important seed-grain crops. The 16th Global Warming International Conference & Expo, New York, NY, April 19-21, 2005. Abstract. Allen, L.H., Albrecht, S.L., Boote, K.J., Thomas, J.M.G., Skirvin, K. Soil carbon sequestration potentials of bahiagrass and rhizome perennial peanut in Florida under current and global warming conditions. Soil and Crop Science Society of Florida 65th Annual Meeting, Boca Raton, FL. May 18-20, 2005. Abstract. Allen, L.H., Boote, K.J., Prasad, P.V.V, Gesch, R.W., Snyder, A.M., Thomas, J.M.G., Vu, J.C.V. Elevated temperature decreases yields of seed grain crops. Soil and Crop Science Society of Florida 65th Annual Meeting, Boca Raton, FL. May 18-20, 2005. Abstract. Allen, L.H., Vu, J.C.V., Ray, J.D. Elevated CO2 and temperature effects on sugarcane plant and ratoon crops. Soil and Crop Science Society of Florida 65th Annual Meeting, Boca Raton, FL. May 18-20, 2005. Abstract. Prasad, V.P.V., Vu J.C., Boote, K.J., Allen, L.H., Jr. Enhancement in leaf photosynthesis and up-regulation of Rubisco in the C4 plant sorghum under elevated growth CO2 and temperature occur at early stages of leaf ontogeny. Plant Biology 2005. Abstract 35. Thomas, J.M.G., Boote, K.J., Prasad, P.V.V., Allen, L. H. Effects of elevated temperature and CO2 on seed quality and composition of annual peanut. Soil and Crop Science Society of Florida 65th Annual Meeting, Boca Raton, FL. May 18-20, 2005. Abstract. Review Publications Baker, J.T., Allen Jr, L.H. 2005. Rice growth, yield and photosynthetic responses to elevated atmospheric carbon dioxide concentration and drought[abstract]. American Society of Agronomy Branch Meeting. Boote, K.J., Allen Jr, L.H., Prasad, P.V., Baker, J.T., Gesch, R.W., Snyder, A.M., Pan, D., Thomas, J.M. 2005. Elevated temperature and CO2 impacts on pollination, reproductive growth, and yield of several globally important crops. Journal of Agricultural Meteorology of Japan. 60:469-474. Vu, J.C.V., Allen, L.H., Jr., Gesch, R.W. 2005. Elevated growth CO2 stimulates photosynthetic enzymes and sucrose metabolism in developing sugarcane leaves. In: van der Est, A., Bruce, D., editors. Photosynthesis: Fundamental Aspects to Global Perspectives. XIIIth International Congress of Photosynthesis Proceedings. pp. 966-968. Vu, J.C.V. 2005.Photosynthesis, growth, and yield of citrus at elevated atmospheric CO2. Journal of Crop Improvement v. 13 (No. 1/2):361-376. Allen Jr, L.H., Heimburg, K.F., Bill, Jr., R.G., Bartholic, J.F., Boote, K.J. 2004. Remotely sensed temperatures and evapotranspiration from heteorogeneous grass and citrus tree-canopy surfaces. Soil and Crop Science Society of Florida Proceedings.. v. 63, p.: 1-20 Newman, Y.C., Sollenberger, L.E., Boote, K.J., Allen Jr, L.H., Vu, J.C., Hall, M.B. 2005. Temperature and carbon dioxide effects on nutritive value of rhizoma peanut herbage. Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting.v 45, p. 316-321