Plant Biology Commons^™

Climate Change And Legume Performance In Grassland Agroecosystems, Lynn E. Sollenberger, M. M. Kohmann

IGC Proceedings (1977-2023)

We reviewed the literature to assess the effect of climate change factors on forage legumes. Whether growing in monoculture or mixtures with grasses, exposing legumes to elevated CO₂ (eCO₂) generally leads to sustained increases in forage accumulation (FA) and N fixation, but elevated temperature (eT) in conjunction with eCO₂ usually reduces magnitude of these responses. In legumes, nodules represent large C sinks, precluding photosynthetic acclimation to eCO₂ observed in non-N fixing plants. Greater N fixation in legume-grass mixtures exposed to eCO₂ is due to greater percentage of legume N derived from symbiotic fixation and …

Cool-Season Perennials And Stability In Year-Round Forage Production Systems, C. D. Teutsch

IGC Proceedings (1977-2023)

Changes in long-term climate normals have resulted in warmer and wetter summers and milder winters in the humid eastern United States. This will likely impact regional forage species adaptation in the long-term and varietal adaptation in the short term. Variety evaluation has been occurring at the University of Kentucky for almost 100 years. There are several considerations for selecting forage species and varieties including regional and local adaptation, productivity, distribution of growth, palatability, nutritive value, anti-quality factors, tolerance to stress, and persistence. Two of the most important criteria are long-term productivity and persistence under grazing, both of which are currently …

Discrepancies Between Observed And Predicted Climate-Driven Net Herbage Accumulation, Alec D. Mackay, Michael B. Dodd, K. J. Hutchinson, Ronaldo Vibart, F. Bilotto

IGC Proceedings (1977-2023)

The decline in net herbage accumulation (NHA) on the high phosphorus (P) fertilizer farmlet (HF) of a long-term P fertilizer and associated sheep grazing experiment in the last 25 years, aligns with the necessity to reduce the on-site nominal sheep stocking rates over the same period on this farmlet. This finding appears at odds with projected climate change driven modelling that forecast a largely positive outcome on pasture growth in summer moist environments. In this paper we explore the apparent discrepancies between the observed and predicted climate-driven NHA by using a climate-driven pasture growth module within a larger process-based model …

Length Of Multi-Year Precipitation And Primary Production Relationships Vary Regionally Across Grasslands In The Central U.S., A. R. Hudson, D. P.C. Peters

IGC Proceedings (1977-2023)

Grasslands in the central United States span large temperature and aridity gradients and regionally differ in their drivers of water availability. These differences likely determine how drought event periodicity and duration can influence grassland growth, and are important to consider as global warming changes energy and water distribution across these systems. Here, we explored frequency patterns in annual grassland plant growth (aboveground net primary productivity (ANPP)) and precipitation (PPT) relationships for over 20 years at six long-term research sites spatially distributed across the central grassland region. We identified the periods (>1 year) these relationships are strongest- and when they …

Response Of Reproductive Phenology To Soil Water Content Of Stipa Breviflora Under Warming And Nitrogen Application, L. Bai, H. Y. Ren, G. D. Han

IGC Proceedings (1977-2023)

Plant phenology is considered as the most direct and sensitive characteristic indicators of plant response to regional climate change. Based on the observation data of phenology and soil water content of Stipa breviflora in an experimental platform of warming and nitrogen application in Inner Mongolia desert steppe from 2009 to 2019. The results showed that warming and nitrogen application significantly advanced the reproductive phenological period (P < 0.001), and the interaction of warming and nitrogen application promoted the advance of reproductive phenological period (P < 0.05).

Is Climate Change Causing The Range Contraction Of Cape Rock-Jumpers (Chaetops Frenatus)?, Gregory D. Duckworth, Raquel A. Garcia, Rheinhardt Scholtz, Res Altwegg

Department of Agronomy and Horticulture: Faculty Publications

Species distribution models often suggest strong links between climate and species' distribution boundaries and project large distribution shifts in response to climate change. However, attributing distribution shifts to climate change requires more than correlative models. One idea is to examine correlates of the processes that cause distribution shifts, namely colonization and local extinction, by using dynamic occupancy models. The Cape Rock-jumper (Chaetops frenatus) has disappeared over most of its distribution where temperatures are the highest. We used dynamic occupancy models to analyse Cape Rock-jumper distribution with respect to climate (mean temperature and precipitation over the warmest annual quarter), …

Structural Diversity And Stress Regulation Of The Plant Immunity-Associated Calmodulin-Binding Protein 60 (Cbp60) Family Of Transcription Factors In Solanum Lycopersicum (Tomato), Vanessa Shivnauth, Sonya Pretheepkumar, Eric J. R. Marchetta, Christina A. M. Rossi, Keaun Amani, Christian Castroverde

Biology Faculty Publications

Cellular signaling generates calcium (Ca2+) ions, which are ubiquitous secondary messengers decoded by calcium-dependent protein kinases, calcineurins, calreticulin, calmodulins (CAMs), and CAM-binding proteins. Previous studies in the model plant Arabidopsis thaliana have shown the critical roles of the CAM-BINDING PROTEIN 60 (CBP60) protein family in plant growth, stress responses, and immunity. Certain CBP60 factors can regulate plant immune responses, like pattern-triggered immunity, effector-triggered immunity, and synthesis of major plant immune-activating metabolites salicylic acid (SA) and N-hydroxypipecolic acid (NHP). Although homologous CBP60 sequences have been identified in the plant kingdom, their function and regulation in most species remain unclear. In …

Potential Climate Change Impacts On Beef Production Systems In Australia, David H. Cobon, K. L. Bell, G. M. Mckeon, J. F. Clewett, S. Crimp

IGC Proceedings (1977-2023)

There is increasing evidence suggesting that Australia's climate is changing due to enhanced levels of greenhouse gases and that it will continue to change (Pittock 2003). Climate changes are partly established, however the impact on systems, industries and process are unclear. Industry distribution reflects climatically imposed boundaries and the relative profitability of alternative land use. Climate change may negatively impact some existing industries but create opportunities for others. This study provides an assessment of the likely impacts of plausible climate change on the beef industry in central Queensland.

Yield Progress Of Perennial Ryegrass And Silage Maize - Genetic Gain Or Climate Change?, Antje Herrmann, A. Kornher, Friedhelm Taube

IGC Proceedings (1977-2023)

Gains in annual dry matter yield (DMY) from breeding achieved during the last decades are reported to range between 2.5 and 6% per decade for perennial ryegrass (Wilkins & Humphreys, 2003). In contrast, accelerated progress in improving DMY has been achieved for silage maize, varying between 8 and 13% per decade (Lauer et al., 2001). These gains are mainly attributed to (i) genetic yield potential increase, (ii) improved crop management and (iii) increased stress tolerance. The potential impact of climate change on yield progress, however, is disregarded in most studies. The objective of this study therefore was to quantify …

Shifts In N-Efficiency Of Different Farm Types In Response To Climate Change, S. Dueri, P. L. Calanca, Juerg Fuhrer

IGC Proceedings (1977-2023)

Climate change may affect European farms, but in contrast to individual crops - the sensitivity of whole farming systems has not been the subject of much research. At the farm level, where different farm units are linked through the availability and flow of nitrogen (N), effects on individual crops are interlinked, and through shifts in grasslands and related animal production with altered nutrient flows. Ideally, N flows into the system and N-export with products should be equal, and thus N-use-efficiency (NUE), expressed as the ratio of N export to N loss, would be maximal. The objective of this study was …

The Effect Of Extremes In Soil Moisture Content On Perennial Ryegrass Growth, A. Scott Laidlaw

IGC Proceedings (1977-2023)

Seasonal distribution of rainfall in the UK and Ireland is predicted to become more variable (Sweeney, 2003). The problems of excessive soil moisture on grass utilisation and the effect of deficit in soil moisture on grass growth are well known. However the effect of excess rainfall on the growth of sown grass is less clear and is usually not taken into account in grass growth models. This study was carried out to investigate the potential impact of excess moisture on perennial ryegrass growth in the field and to investigate the relative effect of soil moisture varying from deficit to excess …

Forage Grass Phenology In Relation To Climate Change, G. Żurek

IGC Proceedings (1977-2023)

Phenological phases of plants, such as heading or flowering are mainly driven by environmental factors such as pests, diseases, competition, soil properties, genetics, age and, most importantly, weather conditions (Menzel & Fabian, 1999; Menzel 2000). At the end of the last century there was an emerging recognition that phenological records can be especially useful in environmental monitoring and it has gained the UK government approval as an indicator of climate change (Sparks et al., 2000). The aim of this work was to analyse long-term trends in the mean heading date for Polish ecotypes of three forage grass species.

Long-Term Responses Of A Mesic Grassland To Manipulation Of Rainfall Quantity And Pattern, A. K. Knapp, J M. Blair, P. A. Fay, M. D. Smith, S. L. Collins, J. M. Briggs

IGC Proceedings (1977-2023)

Climatic variability is an inherent feature of grassland biomes, with large fluctuations in temperatures combined with precipitation regimes characterised by floods and severe drought occurring on both an interannual and seasonal scale. Global climate models and emerging data indicate that extremes in precipitation regimes are increasing worldwide coupled with increases in temperature. Thus, variability in spatial and temporal patterns of water availability in grasslands, as directly influenced by altered precipitation patterns and indirectly by increased temperatures, will likely increase in the future. The objectives of our experiments were to experimentally manipulate rainfall amount and temporal patterns (amount and timing of …

Sources And Sinks Of Greenhouse Gases From European Grasslands And Mitigation Options: The ‘Greengrass’ Project, Jean-François Soussana, V. Allard, P. Ambus, C. Amman, P. Berbigier, C. Campbell, P. Cellier, E. Ceschia, P. Ciais, J. Clifton-Brown, S. Czóbel, R. Domingues, T. De Groot, R. Falcimagne, C. Flechard, J. Fuhrer, G. Gaborit, L. Horváth, A. Hensen, M. B. Jones, S. Jones, G. Kasper, K. Klumpp, P. Laville, C. Martin, C. Milford, Z. Nagy, A. Neftel, E. Nemitz, J. E. Olesen, A. Patterson, K. Pilegaard, A. Raschi, R. Rees, U. Skiba, P. Stefani, S. Salètes, P. Smith, M. A. Sutton, Z. Tuba, A. Van Amstel, A. Van Den Pol-Van Dasselaar, N. Viovy, N. Vuichard, M. Wattenbach, T. Wedinger

IGC Proceedings (1977-2023)

Adapting the management of grasslands may be used to enhance carbon sequestration into soil, but could also increase N₂O and CH₄ emissions. In support of the European post-Kyoto policy, the European 'GreenGrass' project (EC FP5, EVK2-CT2001-00105) has three main objectives: i) to reduce the large uncertainties concerning the estimates of CO₂, N₂O and CH₄ fluxes to and from grassland plots under different climatic conditions and assess their global warming potential, ii) to measure net greenhouse gas (GHG) fluxes for different management which reflect potential mitigation options, iii) to construct a model of …

Impact Of Climate Change On Potential Distribution And Relative Abundance Of The Migratory Grasshopper (Orthoptera: Acrididae) In The Prairie Ecosystem Of Canada, Owen Olfert, R. Weiss

IGC Proceedings (1977-2023)

Climate is the dominant force determining the distribution and abundance of most insect pest species. There has been considerable concern in recent years about climatic warming caused by human activities and the affects of these changes on agriculture in North America. Warming conditions may affect insect populations by altering timing of emergence, increased growth and development rates, shorter generation times and reduced overwintering mortality (McCarthy et al. 2001). Given that the magnitude of predicted temperature change associated with global warming is beyond the historical experience of modern agriculture computer models are one method by which researchers can study the possible …

Irish Dairy Farming: Effects Of Introducing A Maize Component On Grassland Management Over The Next 50 Years, A. J. Brereton, N. M. Holden

IGC Proceedings (1977-2023)

Typical management of Irish dairy units is based on a low-cost spring-calving strategy with 90% of annual feed derived from grass grown on the farm. Almost 70% of feed is from grazed grass managed by rotational grazing, the remainder is conserved forage and concentrates. The objectives of the work were to examine how the management system has to be modified when part of the dairy unit land is allocated to maize silage instead of grass silage production, and to examine how climate change over the next 50 years will impact on grass and maize management within the production system.

The Potential Of Grassland And Associated Forages To Produce Fibre, Biomass, Energy Or Other Feedstocks For Non-Food And Other Sectors: New Uses For A Global Resource, M. F. Askew

IGC Proceedings (1977-2023)

1. In developed countries increased areas of land will become available for non-food production. Recent reforms of the Common Agricultural Policy will further intensify this trend in Europe.
2. There is potential for grassland and associated species to contribute to large tonnage markets of energy and bulk fibres, to the supply of fermentation products and to speciality markets, but processes and approaches to the market are not as yet developed.
3. There is potential for the establishment of Graminaceous species - specifically for non- food use. For European conditions particular attention is being given to Miscanthus sinensis (Miscanthus), Arundo donax (Giant Reed), Phalaris …

Molecular Regulation Of The Salicylic Acid Hormone Pathway In Plants Under Changing Environmental Conditions, Christina A. M. Rossi, Eric J. R. Marchetta, Jong Hum Kim, Christian Castroverde

Biology Faculty Publications

Salicylic acid (SA) is a central plant hormone mediating immunity, growth, and development. Recently, studies have highlighted the sensitivity of the SA pathway to changing climatic factors and the plant microbiome. Here we summarize organizing principles and themes in the regulation of SA biosynthesis, signaling, and metabolism by changing abiotic/biotic environments, focusing on molecular nodes governing SA pathway vulnerability or resilience. We especially highlight advances in the thermosensitive mechanisms underpinning SA-mediated immunity, including differential regulation of key transcription factors (e.g., CAMTAs, CBP60g, SARD1, bHLH059), selective protein–protein interactions of the SA receptor NPR1, and dynamic phase separation of the recently identified …

Natural Variation In Temperature-Modulated Immunity To Pseudomonas Syringae Pv. Tomato (Pst Dc3000) In Arabidopsis Thaliana Plants, Christina A. M. Rossi

Theses and Dissertations (Comprehensive)

Studies conducted on the model plant-pathogen system Arabidopsis thaliana-Pseudomonas syringae pv. tomato (Pst) showed that elevated temperature suppresses the pathogen-induced production of salicylic acid (SA), which is a key plant defence hormone. This increased host vulnerability at higher temperatures is due to downregulated expression of CALMODULIN BINDING PROTEIN 60-LIKE G (CBP60g) and SYSTEMIC ACQUIRED RESISTANCE DEFICIENT 1 (SARD1), which encode master regulators of SA production. Collectively, these previous studies only focused on one natural accession of Arabidopsis called Columbia-0 (Col-0). However, the intraspecific variation in Arabidopsis immunity phenotypes under elevated temperature remains unknown. To fill this critical knowledge gap, my …

Quantifying The Carbon Stored And Sequestered By The Trees On Pomona College’S Campus, Paola A. Giron-Carson

Scripps Senior Theses

We are experiencing a climate crisis that must be confronted with strategic mitigation. Pomona College contributes to the climate crisis through its emissions for which there is a baseline record. However there is no baseline record of the climate mitigation currently performed by the trees on Pomona’s campus through carbon storage. This study seeks to determine a current baseline quantity of carbon stored and sequestrated by Pomona’s trees as well as possible courses of climate mitigation for Pomona College to take. Initial information gathering was conducted through interviews with several stakeholders. This study was conducted using data collected prior to …

Changes In Ecosystem Processes And Functional Traits Over An Elevational Gradient, Tiana Issa

Honors Theses

Elevation gradients have been used to understand how climate change impacts various ecosystems processes by substituting distance across elevation with time, reflecting a previous, colder climate. To monitor the changes in soil organic carbon (SOC), plant community, and functional traits across time in the face of climate change, this study used space-for-time substitution to emulate a long-term study with elevational gradients and revisited the same gradient for nearly two decades to monitor elevational effects across time. With this research, I aim to answer the following questions: (1) How does elevation impact ecosystem processes and alpine plant traits? (2) How does …

Bison Movements Change With Weather: Implications For Their Continued Conservation In The Anthropocene, Nicholas A. Mcmillan, Samuel D. Fuhlendorf, Barney Luttbeg, Laura E. Goodman, Craig A. Davis, Brady W. Allred, Robert G. Hamilton

Department of Agronomy and Horticulture: Faculty Publications

Animal movement patterns are affected by complex interactions between biotic and abiotic landscape conditions, and these patterns are being altered by weather variability associated with a changing climate. Some animals, like the American plains bison (Bison bison L.; hereafter, plains bison), are considered keystone species, thus their response to weather variability may alter ecosystem structure and biodiversity patterns. Many movement studies of plains bison and other ungulates have focused on point-pattern analyses (e.g., resource-selection) that have provided information about where these animals move, but information about when or why these animals move is limited. For example, information surrounding the …

Chromosome Number Evolution, Phylogeography, And The Effects Of Climate Change On Species Distributions In Polyploid Plant Systems, Courtney H. Babin

LSU New Orleans Theses and Dissertations

Polyploidy, a term used to describe organisms with cells having more than two paired sets of chromosomes, is a significant driver of diversification among land plants. Over a century of research has advanced our understanding of polyploidization in some taxa, but polyploid organisms remain understudied. In this dissertation, I investigate chromosome number evolution, phylogeographic structure, genetic differentiation, and the effects of climate change on ploidy level distribution using polyploid plant systems. In the first chapter, I inferred a molecular phylogeny of Allium, an economically important genus that includes cultivated crops and ornamentals, to investigate evolutionary transitions in chromosome number …

Differential Regulation Of Flower Transpiration During Abiotic Stress In Annual Plants, Ranjita Sinha, Sara I. Zandalinas, Yosef Fichman, Sidharth Sen, Shuai Zeng, Aurelio Gómez-Cadenas, Trupti Joshi, Felix B. Fritschi, Ron Mittler

Biomedical Sciences

Heat waves occurring during droughts can have a devastating impact on yield, especially if they happen during the flowering and seed set stages of the crop cycle. Global warming and climate change are driving an alarming increase in the frequency and intensity of combined drought and heat stress episodes, critically threatening global food security. Because high temperature is detrimental to reproductive processes, essential for plant yield, we measured the inner temperature, transpiration, sepal stomatal aperture, hormone concentrations and transcriptomic response of closed soybean flowers developing on plants subjected to a combination of drought and heat stress. Here, we report that, …

Increasing The Resilience Of Plant Immunity To A Warming Climate, Jong Hum Kim, Christian Castroverde, Shuai Huang, Chao Li, Richard Hilleary, Adam Seroka, Reza Sohrabi, Diana Medina-Yerena, Bethany Huot, Jie Wang, Sharon Marr, Mary Wildermuth, Tao Chen, John Macmicking, Sheng Yang He

Biology Faculty Publications

Extreme weather conditions associated with climate change affect many aspects of plant and animal life, including the response to infectious diseases. Production of salicylic acid (SA), a central plant defence hormone, is particularly vulnerable to suppression by short periods of hot weather above the normal plant growth temperature range via an unknown mechanism. Here we show that suppression of SA production in Arabidopsis thaliana at 28 °C is independent of PHYTOCHROME B (phyB) and EARLY FLOWERING 3 (ELF3), which regulate thermo-responsive plant growth and development. Instead, we found that formation of GUANYLATE BINDING PROTEIN-LIKE 3 (GBPL3) defence-activated biomolecular condensates (GDACs) …

Climate Change And Management Impacts On Soybean N Fixation, Soil N Mineralization, N2O Emissions, And Seed Yield, Elvis F. Elli, Ignacio A. Ciampitti, Michael J. Castellano, Larry C. Purcell, Seth Naeve, Patricio Grassini, Nicolas C. La Menza, Luiz Moro Rosso, André F. De Borja Reis, Péter Kovács, Sotirios V. Archontoulis

Department of Agronomy and Horticulture: Faculty Publications

Limited knowledge about how nitrogen (N) dynamics are affected by climate change, weather variability, and crop management is a major barrier to improving the productivity and environmental performance of soybean-based cropping systems. To fill this knowledge gap, we created a systems understanding of agroecosystem N dynamics and quantified the impact of controllable (management) and uncontrollable (weather, climate) factors on N fluxes and soybean yields. We performed a simulation experiment across 10 soybean production environments in the United States using the Agricultural Production Systems sIMulator (APSIM) model and future climate projections from five global circulation models. Climate change (2020–2080) increased N …

Methane And Nitrous Oxide Emissions From Grazed Grasslands, Harry Clark, C. Pinares-Patiño, C. De Klein

IGC Proceedings (1977-2023)

Key points

1. Emissions of methane (CH₄) and nitrous oxide (N₂O) from grasslands make a substantial contribution to total agricultural emissions of these two gases.

2. At present practical mitigation options that relate to grazing ruminants and grazed pastures are limited.

3. Research into agricultural greenhouse gas emissions is of low priority in most developed countries.

4. Direct manipulation of the rumen ecosystem provides the best opportunity for large reductions in CH₄ in the long term.

5. Reducing the amount of nitrogen (N) excreted by grazing animals is a priority in N₂O research, …

Global Atmospheric Change And Its Effect On Managed Grassland Systems, Andreas Lüscher, J. Fuhrer, P. C. D. Newton

IGC Proceedings (1977-2023)

Key points

1. Increasing atmospheric CO2 concentration and a trend to warmer mean temperatures are the most reliable aspects of global atmospheric change. Projections of the extent of climate change and the frequency of extreme weather conditions remain uncertain.

2. Research has considerably reduced the uncertainty about effects of global atmospheric change on physiology of plants, productivity and species composition of plant communities.

3. Other factors (e.g. nutrient availability, soil type) and long-term adaptation of the ecosystem (e.g. nutrient cycling and sequestration) influence the response of plant communities to global atmospheric change. Generalisation is not possible with respect to the …

The Potential Of Grassland And Associated Forages To Produce Fibre, Biomass, Energy Or Other Feedstocks For Non-Food And Other Sectors: New Uses For A Global Resource, M. F. Askew

IGC Proceedings (1977-2023)

Key points

1. In developed countries increased areas of land will become available for non-food production. Recent reforms of the Common Agricultural Policy will further intensify this trend in Europe.

2. There is potential for grassland and associated species to contribute to large tonnage markets of energy and bulk fibres, to the supply of fermentation products and to speciality markets, but processes and approaches to the market are not as yet developed.

3. There is potential for the establishment of Graminaceous species - specifically for nonfood use. For European conditions particular attention is being given to Miscanthus sinensis (Miscanthus), Arundo …

Estimation Of The Optimal Nitrogen Dose In A Brachiaria Humidicola-Corn Rotation System In The Colombian Eastern Plains, K. Enciso, S. Burkart

IGC Proceedings (1977-2023)

Improving nitrogen (N) use efficiency by optimizing the N fertilizer application dose is one way to reduce greenhouse gas (GHG) emissions in agriculture and livestock production, especially in higher demanding crops such as corn. Taking a Brachiaria humidicola (Bh)-corn rotation system in the Colombian Eastern Plains, we seek to determine both the optimal economic dose (OED) and the optimal technical dose (OTD) of N, which allow to maximize income at producer level and minimize environmental impacts. This particular rotation system was chosen as research subject given the presence of the residual effect of Biological Nitrogen Inhibition (BNI) in …