Progress 07/01/03 to 05/26/05
Outputs
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? The concentration of carbon dioxide in the atmosphere is increasing rapidly. In addition to its role in global warming, increased carbon dioxide has many direct effects on plants, including changes in growth rate and the nutritional value of plant products. One of the changes expected with increased carbon dioxide is a reduction in water loss from leaves. This could have an impact on crop water use and on climate. However, the effects of elevated carbon dioxide on plants differ greatly among species and with other environmental factors such as high temperature and drought and, because the mechanisms of responses are not sufficiently understood, have proven very difficult to predict under field conditions. The purpose of this work is to enhance our understanding of crop and weed responses to the
continuing increase in atmospheric carbon dioxide concentration and how responses of plants may affect global climate, crop/weed competition, and crop yield, and to increase our ability to adapt crops to the rising atmospheric carbon dioxide concentration. This work is part of NP204, Global Change. 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met, substantially met, or not met. If not met, why. 1. There were no milestones listed beyond 2003. The project was terminated in June, 2005. Milestone Not Met Other 3b List the milestones that you expect to address over the next 3 years (FY 2006, 2007, and 2008). What do you expect to accomplish, year by year, over the next 3 years under each milestone? None. The project was terminated in June, 2005. 4a What was the single most significant accomplishment this past year? "CO2 at night affects multiple plant processes." Work in the Crop Systems and Global Change
Laboratory has shown that carbon dioxide concentration in the dark affects respiration, translocation and nitrate reduction. This work indicates that the view that carbon dioxide concentration is important to plants only in the daytime and that it directly affects only photosynthesis and stomatal conductance is not correct. This work will help researchers design more realistic experiments concerning crop responses to rising atmospheric carbon dioxide. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Identified reduced hydraulic conductance as a common response of plants to growth at elevated carbon dioxide, which explains why plant water relations are often not improved by elevated carbon dioxide. This has a major impact on modeling plant growth responses to increasing atmospheric carbon dioxide. Determined that elevated carbon dioxide decreases the ratio of respiration to photosynthesis, but that growth temperature does
not affect the ratio. The ratio of respiration to photosynthesis has an impact on the plant growth and global carbon balance, and knowledge of how these respond to elevated carbon dioxide and temperature will help to predict and prepare agriculture for global change. Better defined the response of stomatal conductance to carbon dioxide concentration, in terms of interactions with humidity and growth environment. This information will improve the ability to predict the impact of increasing atmospheric carbon dioxide concentration on climate. Demonstrated that photosynthetic acclimation to elevated carbon dioxide occurred under field conditions in winter wheat and barley, and identified premature senescence as a factor in this acclimation. This information will improve the ability to predict the impact of increasing atmospheric carbon dioxide concentration on crop growth. Demonstrated that significant variation exists among modern cultivars of soybean in the response of seed yield to
elevated carbon dioxide. This information will aid breeders adapting crops to increasing atmospheric carbon dioxide. Determined that growth at elevated carbon dioxide causes acclimation of light-limited photosynthesis in some species, and that in potato acclimation of light- saturated photosynthesis to elevated carbon dioxide involves lower activity but not content of the rubisco enzyme. This information will aid scientists predicting how crop growth would respond to increasing atmospheric carbon dioxide concentrations. Demonstrated under greenhouse conditions that elevated carbon dioxide reduces the effectiveness of glyphosate in controlling some weeds. Determined that seed yield losses in soybeans caused by weeds increased with elevated carbon dioxide in field trials. These results indicate that weed control may become more difficult as atmospheric carbon dioxide increases. Determined the effect of increasing atmospheric carbon dioxide on water loss from soybean and corn fields, and
quantified the changes on crop microclimate, and the feedback between direct crop responses to carbon dioxide and climate feedback systems. This information will be of use in predicting climate and crop water use as atmospheric carbon dioxide increases. Demonstrated that the increase in atmospheric CO2 since 1900 altered the growth and morphology of Canada thistle, a widely recognized invasive weed. These results suggest that as CO2 increases, control efforts for this weed could be more difficult. Demonstrated that production losses due to weeds are exacerbated at elevated CO2 for a widely grown C4 crop, grain sorghum. This result confirms earlier work showing that weeds may show a stronger increase in growth with rising CO2 than some crop species. Showed that carbon dioxide concentration during the dark affects translocation from leaves, indicating that changes in dark respiration caused by carbon dioxide concentration have physiological ramifications. Determined that exogenous
trehalose changed the expression of over thirty genes in Arabidopsis thaliana. These genes were mostly involved in cellular metabolism and development. Three genes encoding nitrilases (Nit1, Nit2 and Nit4) were repressed by trehalose. Nit1 and Nit2 are involved in indole metabolism (plant hormones), whereas Nit4 detoxifies cyanide (plant defense). These results indicated that exogenous trehalose is a powerful regulator of plant gene expression. Determined that photosynthetic down-regulation at elevated carbon dioxide in collards was caused directly by the accumulation of soluble carbohydrates and its magnitude and occurrence under field conditions varied predictably with the weather. Down-regulation of photosynthesis at elevated carbon dioxide strongly affects how crop yields respond, and our inability to predict its occurrence has been a major limitation in forecasting crop responses to global change. Demonstrated that projected changes in carbon dioxide concentration and temperature
for the globe as a whole are already occurring in urban environments, with impacts on plants, such as increasing ragweed pollen production. Comparing plants in urban and rural environments could aid in forecasting the combined effects of increased carbon dioxide and temperature on crop and weed growth. The effects of inorganic phosphate (Pi) insufficiency and of carbon dioxide enrichment on assimilate partitioning in barley roots were studied using nine to 17- day old plants. Enhanced carbon dioxide partially reversed the inhibition of growth imposed by Pi insufficiency. Both carbon dioxide enrichment and Pi insufficiency increased soluble carbohydrate levels in barley roots and the combined effects of these two treatments were additive. This indicated that the capacity of barley roots to utilize carbohydrates from shoots was inadequate under both Pi insufficiency and under carbon dioxide enrichment. These findings also emphasize the importance of avoiding nutrient stress during
carbon dioxide enrichment experiments.
Impacts
(N/A)
Publications
- Wang, S.Y., Bunce, J.A. 2004. Elevated carbon dioxide affects fruit quality and aroma volatile composition in field-grown strawberries (fragaria x ananassa duch).. Journal of the Science of Food and Agriculture. 51:4315-4320.
- Bae, H., Herman, E.M., Sicher Jr, R.C. 2005. Exogenous trehalose induces chemical detoxification and stress response proteins and promotes nonstructural carbohydrate accumulation in arabidopsis thaliana grown in liquid culture. Plant Science.168:1293-1301.
- Bunce, J.A. 2005. Respiration of mature soybean leaves grown at ambient and elevated carbon dioxide concentrations under field conditions. Annals Of Botany. 95:1059-1066.
- Ziska, L.H., Reeves III, J.B., Blank, R.R. 2005. The impact of recent increases in atmospheric co2 on biomass production and vegetative retention of cheatgrass (bromus tectorum): implications for fire disturbance. Global Change Biology. 11:1325-1332.
- Ziska, L.H. 2004. Rising carbon dioxide and weed ecology. Weed Ecology and Management. pp. 159-176
- Ziska, L.H., Morris, C.F., Goins, E.W. 2004. Responses of wheat varieties released since 1903 to increasing atmospheric carbon dioxide:is empirical selection sufficient to maximize production. Global Change Biology. 10:810- 1819.
- Bunce, J.A. 2004. A comparison of the effects of carbon dioxide concentration and temperature on respiration, translocation, and nitrate reduction in darkened soybean leaves. Annals Of Botany. 93:665-669.
- Bunce, J.A. 2004. Carbon dioxide effects on stomatal responses to the environment and water use by crops under field conditions. Oecologia. 140:1-10.
- Ziska, L.H., Faulkner, S.S., Lydon, J. 2004. Changes in biomass and root:shoot ratio in a field-grown, noxious perennial weed, canada thistle (cirsium arvense l. scop.) with elevated co2: implications for chemical control by glyphosate. Weed Science. 52:584-588.
- Ziska, L.H., George, K. 2004. Rising carbon dioxide and invasive, noxious plants: Potential threats and consequences. World Resource Review. 16:427- 447.
- Ziska, L.H. 2003. Rising Carbon Dioxide & Implications for Weed-Crop Management. New, T.W., Bear, D.S., Peny, S., Dawe, D. & Hady, B. Rice Science: Innovations and Impact for Livelihood. Manila, Philippines: IRRI Press. p. 615-634.
- Sicher Jr, R.C. 2005. Interactive effects of inorganic phosphate nutrition and carbon dioxide enrichment on assimilate partitioning in barley roots. Physiologia Plantarum. 123:219-226.
- Singer, B.D., Ziska, L.H., Frenz, D.A., Gebhard, D.E., Straka, J.G. 2005. Increasing amb a 1 content in common ragweed (ambrosia artemisiifolia l.) pollen as a function of rising atmospheric co2 concentration. Functional Plant Biology. 32:667-670.
- Baligar, V.C., Bunce, J.A., Bailey, B.A., Machado, R.C., Pomella, A.W. 2004. Carbon dioxide and photosynthetic photon flux density effects on growth and mineral uptake parameters of cacao. Journal of Food Agriculture and the Environment 3:142-147.
|
Progress 10/01/03 to 09/30/04
Outputs
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? The concentration of carbon dioxide in the atmosphere is increasing rapidly. In addition to its role in global warming, increased carbon dioxide has many direct effects on plants, including changes in growth rate and the nutritional value of plant products. One of the changes expected with increased carbon dioxide is a reduction in water loss from leaves. This could have an impact on crop water use and on climate. However, the effects of elevated carbon dioxide on plants differ greatly among species and with other environmental factors such as high temperature and drought and, because the mechanisms of responses are not sufficiently understood, have proven very difficult to predict under field conditions. The purpose of this work is to enhance our understanding of crop and weed responses to the
continuing increase in atmospheric carbon dioxide concentration and how responses of plants may affect global climate, crop/weed competition, and crop yield, and to increase our ability to adapt crops to the rising atmospheric carbon dioxide concentration. 2. List the milestones (indicators of progress) from your Project Plan. Increase our ability to predict the response of crops and weeds to the ongoing increase in carbon dioxide in the atmosphere. Determine how responses are modified by other environmental factors. Determine how crop water use may be affected. Identify traits which improve the response of the growth of crop plants to increasing atmospheric carbon dioxide. There were no milestones listed beyond 2003, the planned expiration date. A draft CRIS project plan with new milestones beginning with 2005 is under review. 3. Milestones: A. 2004: The existing CRIS had milestones only through 2003 (its scheduled termination date) and the draft new project plan is under
review. In 2004, our accomplishments were all consistent with the objectives of the current CRIS: Increase our ability to predict the response of crops and weeds to the ongoing increase in carbon dioxide in the atmosphere. Determine how responses are modified by other environmental factors. Determine how crop water use may be affected. Identify traits which improve the response of the growth of crop plants to increasing atmospheric carbon dioxide. Substantial progress was made on all of these objectives in 2004. B. 2005 (Based on the draft project plan which has not yet been approved) : Characterize the effects of carbon dioxide enrichment on various antioxidants involved in preventing oxygen damage during photosynthesis. Generate transformed plants with modified levels of proteins that respond to elevated atmospheric carbon dioxide. Examine changes in secondary succession with increasing carbon dioxide and temperature. Determine whether increasing carbon dioxide affects
antioxidant levels in fruits and vegetables. Determine whether the change in atmospheric carbon dioxide that has already occurred has resulted in changes in the quality of wheat flour. Examine variation among soybean cultivars in the response to high temperature stress in combination with elevated carbon dioxide. 2006: Determine whether elevated concentrations of CO2 and warmer temperatures accelerate successional development of plant communities. Determine whether plant growth in elevated carbon dioxide effects the ability of plants to withstand antioxidant stress. Examine variation among soybean cultivars in the response of seed yield to drought in combination with elevated carbon dioxide. 2007: Examine metabolic profiles of Arabidopsis and soybean plants grown at ambient and elevated carbon dioxide concentrations using derivitization, gas chromatography and mass spectrometry to quantify eight different compounds in a single sample. Determine effects of elevated carbon dioxide
on the yield and persistence of alfalfa. Examine the effect of elevated carbon dioxide on the efficacy of glyphosate in controlling noxious weeds. 4. What were the most significant accomplishments this past year? A. As the atmospheric carbon dioxide concentration rose during the last century, the economic impact of invasive weeds increased dramatically. Research at Beltsville has shown that the growth rate of several of the most important invasive weeds has increased much more with the past increase in carbon dioxide concentration than any other species which have been studied. This suggests that rising atmospheric carbon dioxide was a factor in the success of invasive weeds, and that there has already been a significant economic cost of this global change. B. None C. None D. None 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Identified reduced hydraulic conductance as a common response of plants to growth at elevated
carbon dioxide, which explains why plant water relations are often not improved by elevated carbon dioxide. This has a major impact on modeling plant growth responses to increasing atmospheric carbon dioxide. Determined that elevated carbon dioxide decreases the ratio of respiration to photosynthesis, but that growth temperature does not affect the ratio. The ratio of respiration to photosynthesis has an impact on the plant growth and global carbon balance, and knowledge of how these respond to elevated carbon dioxide and temperature will help to predict and prepare agriculture for global change. Better defined the response of stomatal conductance to carbon dioxide concentration, in terms of interactions with humidity and growth environment. This information will improve the ability to predict the impact of increasing atmospheric carbon dioxide concentration on climate. Demonstrated that photosynthetic acclimation to elevated carbon dioxide occurred under field conditions in
winter wheat and barley, and identified premature senescence as a factor in this acclimation. This information will improve the ability to predict the impact of increasing atmospheric carbon dioxide concentration on crop growth. Demonstrated that significant variation exists among modern cultivars of soybean in the response of seed yield to elevated carbon dioxide. This information will aid breeders adapting crops to increasing atmospheric carbon dioxide. Determined that growth at elevated carbon dioxide causes acclimation of light-limited photosynthesis in some species, and that in potato acclimation of light-saturated photosynthesis to elevated carbon dioxide involves lower activity but not content of the rubisco enzyme. This information will aid scientists predicting how crop growth would respond to increasing atmospheric carbon dioxide concentrations. Demonstrated under greenhouse conditions that elevated carbon dioxide reduces the effectiveness of glyphosate in controlling
some weeds. Determined that seed yield losses in soybeans caused by weeds increased with elevated carbon dioxide in field trials. These results indicate that weed control may become more difficult as atmospheric carbon dioxide increases. Determined the effect of increasing atmospheric carbon dioxide on water loss from soybean and corn fields, and quantified the changes on crop microclimate, and the feedback between direct crop responses to carbon dioxide and climate feedback systems. This information will be of use in predicting climate and crop water use as atmospheric carbon dioxide increases. Demonstrated that the increase in atmospheric CO2 since 1900 altered the growth and morphology of Canada thistle, a widely recognized invasive weed. These results suggest that as CO2 increases, control efforts for this weed could be more difficult. Demonstrated that production loses due to weeds are exacerbated at elevated CO2 for a widely grown C4 crop, grain sorghum. This result
confirms earlier work showing that weeds may show a stronger increase in growth with rising CO2 than some crop species. Showed that carbon dioxide concentration during the dark affects translocation from leaves, indicating that changes in dark respiration caused by carbon dioxide concentration have physiological ramifications. Determined that exogenous trehalose changed the expression of over thirty genes in Arabidopsis thaliana. These genes were mostly involved in cellular metabolism and development. Three genes encoding nitrilases (Nit1, Nit2 and Nit4) were repressed by trehalose. Nit1 and Nit2 are involved in indole metabolism (plant hormones), whereas Nit4 detoxifies cyanide (plant defense). These results indicated that exogenous trehalose is a powerful regulator of plant gene expression. Identified six proteins that were modified by growth at elevated carbon dioxide in Arabidopsis: myrosinase precursor, luminal binding protein 2, putative 3-beta hydroxysteroid
dehydrogenase/isomerase protein, nucleoside dikinase II, major latex protein-related, and photosystem-II oxygen evolving complex 23. Four of these proteins have known functions, whereas the functions of the others cannot be identified with certainty from the genome database. These findings indicate that, in addition to photosynthesis, carbon dioxide enrichment affected genes involved in plant defense and in the regulation of development. Determined that photosynthetic down-regulation at elevated carbon dioxide in collards was caused directly by the accumulation of soluble carbohydrates and its magnitude and occurrence under field conditions varied predictably with the weather. Down-regulation of photosynthesis at elevated carbon dioxide strongly affects how crop yields respond, and our inability to predict its occurrence has been a major limitation in forecasting crop responses to global change. Demonstrated that projected changes in carbon dioxide concentration and temperature
for the globe as a whole are already occurring in urban environments, with impacts on plants, such as increasing ragweed pollen production. Comparing plants in urban and rural environments could aid in forecasting the combined effects of increased carbon dioxide and temperature on crop and weed growth. 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? Knowledge of the responses of fruit yield of strawberry plants and photosynthesis of pepper plants to elevated carbon dioxide was transferred to private companies seeking to commercialize carbon dioxide fertilization for the production of field-grown strawberries and peppers.
Impacts
(N/A)
Publications
- Zhou, R., Sicher Jr, R.C., Cheng, L., Quebedeaux, B. 2003. Regulation of apple leaf aldose-6-phosphate reductase activity by inorganic phosphate and divalent cations. Functional Plant Biology. 30:1037-1043.
- Ziska, L.H., Gebhard, D.E., Frenz, D.A., Faulkner, S.S., Singer, B.D., Straka, J.G. 2003. Cities as harbingers of climate change: common ragweed, urbanization and public health. Journal of Allergy Clinical Immunology. 111(2):290-295.
- Ziska, L.H. 2003. Evaluation of yield loss in field-grown sorghum from a c3 and c4 weed as a function of increasing atmospheric carbon dioxide. Weed Science. 51:914-918.
- Ziska, L.H. 2003. Climate change, plant biology and public health. World Resource Review. 15(3):271-288.
- Bunce, J.A. 2003. Responses of seedling growth to daytime or continuous elevation of carbon dioxide. International Journal of Plant Science. 164:377-382.
- Wang, S.Y., Bunce, J.A., Maas, J. 2003. Elevated carbon dioxide increases contents of antioxidant compounds in field-grown strawberries. Journal of Agricultural and Food Chemistry. 51:4315-4320.
- Bunce, J.A., Sicher Jr, R.C. 2004. Daily irradiance and feedback inhibition of photosynthesis of elevated carbon dioxide in brassica oleracea. Photosynthesis Research. 41:481-488.
- Ziska, L.H., Bunce, J.A., Goins, E.W. 2004. Initial changes in plant population and productivity during secondary succession along an in situ gradient of carbon dioxide and temperature. Oecologia. 139:454-458.
- Ziska, L.H. 2003. Evaluation of the response of invasive species to past, present and future co2. Journal of Experimental Botany. 54:395-404.
- Ziska, L.H. 2003. Canada thistle (cirsium arvense l. scop.) to recent increases in atmospheric carbon dioxide. Physiologia Plantarum. 119:105- 112.
|