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Silva-Perez V, Shunmugam ASK, Rao S, Cossani CM, Tefera AT, Fitzgerald GJ, Armstrong R, Rosewarne GM. Breeding has selected for architectural and photosynthetic traits in lentils. Front Plant Sci 2022; 13:925987. [PMID: 36092438 PMCID: PMC9453451 DOI: 10.3389/fpls.2022.925987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/10/2022] [Indexed: 06/15/2023]
Abstract
Genetic progress in seed yield in lentils (Lens culinaris Medik) has increased by 1.1% per year in Australia over the past 27 years. Knowing which plant traits have changed through breeding during this time can give important insights as to how lentil yield has increased. This study aims to identify morphological and physiological traits that were directly or indirectly selected between 1993 and 2020 in the Australian lentil breeding program using 2 years of experimental data. Major changes occurred in plant architecture during this period. Divergent selection has seen the release of varieties that have sprawling to very upright types of canopies. Despite this genetic diversity in recently released varieties, there is an overall tendency of recently released varieties having increased plant height and leaf size with reduced number of branches. Increased light interception was positively correlated with year of release (YOR) and yield, and likely results from indirect selection of yield and taller plant types. There is an indication that recently released varieties have lower CO2 assimilation rate, stomatal conductance and canopy temperature depression (CTD) at high ambient temperatures (~30°C). Understanding lentil physiology will assist in identifying traits to increase yield in a changing climate with extreme weather events.
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Affiliation(s)
| | | | | | - C. Mariano Cossani
- School of Agriculture, Food and Wine, South Australian Research and Development Institute, The University of Adelaide, Urrbrae, SA, Australia
| | | | - Glenn J. Fitzgerald
- Agriculture Victoria, Horsham, VIC, Australia
- Centre for Agricultural Innovation, School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Roger Armstrong
- Agriculture Victoria, Horsham, VIC, Australia
- Department of Animal, Plant and Soil Sciences, La Trobe University, Melbourne, VIC, Australia
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2
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Bourgault M, Webber HA, Chenu K, O'Leary GJ, Gaiser T, Siebert S, Dreccer F, Huth N, Fitzgerald GJ, Tausz M, Ewert F. Early vigour in wheat: Could it lead to more severe terminal drought stress under elevated atmospheric [CO 2 ] and semi-arid conditions? Glob Chang Biol 2020; 26:4079-4093. [PMID: 32320514 DOI: 10.1111/gcb.15128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/19/2020] [Indexed: 06/11/2023]
Abstract
Early vigour in wheat is a trait that has received attention for its benefits reducing evaporation from the soil surface early in the season. However, with the growth enhancement common to crops grown under elevated atmospheric CO2 concentrations (e[CO2 ]), there is a risk that too much early growth might deplete soil water and lead to more severe terminal drought stress in environments where production relies on stored soil water content. If this is the case, the incorporation of such a trait in wheat breeding programmes might have unintended negative consequences in the future, especially in dry years. We used selected data from cultivars with proven expression of high and low early vigour from the Australian Grains Free Air CO2 Enrichment (AGFACE) facility, and complemented this analysis with simulation results from two crop growth models which differ in the modelling of leaf area development and crop water use. Grain yield responses to e[CO2 ] were lower in the high early vigour group compared to the low early vigour group, and although these differences were not significant, they were corroborated by simulation model results. However, the simulated lower response with high early vigour lines was not caused by an earlier or greater depletion of soil water under e[CO2 ] and the mechanisms responsible appear to be related to an earlier saturation of the radiation intercepted. Whether this is the case in the field needs to be further investigated. In addition, there was some evidence that the timing of the drought stress during crop growth influenced the effect of e[CO2 ] regardless of the early vigour trait. There is a need for FACE investigations of the value of traits for drought adaptation to be conducted under more severe drought conditions and variable timing of drought stress, a risky but necessary endeavour.
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Affiliation(s)
- Maryse Bourgault
- Northern Agricultural Research Center, Montana State University, Havre, MT, USA
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Creswick, Vic., Australia
| | - Heidi A Webber
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
- Leibniz Centre for Agricultural Landscape Research (ZALF), Brandenburg, Germany
| | - Karine Chenu
- Queensland Alliance for Agriculture and Food Innovation (QAAFI), University of Queensland, Toowoomba, Qld, Australia
| | - Garry J O'Leary
- Agriculture Victoria, Grains Innovation Park, Horsham, Vic., Australia
| | - Thomas Gaiser
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
| | - Stefan Siebert
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
- Department of Crop Sciences, University of Göttingen, Göttingen, Germany
| | - Fernanda Dreccer
- CSIRO Agriculture and Food, Cooper Laboratory, University of Queensland, Gatton, Qld, Australia
| | - Neil Huth
- CSIRO Agriculture and Food, Toowoomba, Qld, Australia
| | - Glenn J Fitzgerald
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Creswick, Vic., Australia
- Agriculture Victoria, Grains Innovation Park, Horsham, Vic., Australia
| | - Michael Tausz
- Department of Agriculture, Science and the Environment, CQ University, Norman Gardens, Qld, Australia
| | - Frank Ewert
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
- Leibniz Centre for Agricultural Landscape Research (ZALF), Brandenburg, Germany
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3
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Houshmandfar A, Ota N, O'Leary GJ, Zheng B, Chen Y, Tausz-Posch S, Fitzgerald GJ, Richards R, Rebetzke GJ, Tausz M. A reduced-tillering trait shows small but important yield gains in dryland wheat production. Glob Chang Biol 2020; 26:4056-4067. [PMID: 32237246 DOI: 10.1111/gcb.15105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 03/13/2020] [Accepted: 03/24/2020] [Indexed: 06/11/2023]
Abstract
Reducing the number of tillers per plant using a tiller inhibition (tin) gene has been considered as an important trait for wheat production in dryland environments. We used a spatial analysis approach with a daily time-step coupled radiation and transpiration efficiency model to simulate the impact of the reduced-tillering trait on wheat yield under different climate change scenarios across Australia's arable land. Our results show a small but consistent yield advantage of the reduced-tillering trait in the most water-limited environments both under current and likely future conditions. Our climate scenarios show that whilst elevated [CO2 ] (e[CO2 ]) alone might limit the area where the reduced-tillering trait is advantageous, the most likely climate scenario of e[CO2 ] combined with increased temperature and reduced rainfall consistently increased the area where restricted tillering has an advantage. Whilst long-term average yield advantages were small (ranged from 31 to 51 kg ha-1 year-1 ), across large dryland areas the value is large (potential cost-benefits ranged from Australian dollar 23 to 60 MIL/year). It seems therefore worthwhile to further explore this reduced-tillering trait in relation to a range of different environments and climates, because its benefits are likely to grow in future dry environments where wheat is grown around the world.
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Affiliation(s)
- Alireza Houshmandfar
- CSIRO Agriculture and Food, Centre for Environment and Life Sciences, Floreat, WA, Australia
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, Vic., Australia
| | - Noboru Ota
- CSIRO Health and Biosecurity, Canberra, ACT, Australia
| | - Garry J O'Leary
- Agriculture Victoria, Horsham, Vic., Australia
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Vic., Australia
| | - Bangyou Zheng
- CSIRO Agriculture and Food, Queensland Bioscience Precinct, St. Lucia, Qld, Australia
| | - Yang Chen
- Goods Shed North, CSIRO Data61, Docklands, Vic., Australia
| | - Sabine Tausz-Posch
- Department of Agriculture, Science and the Environment, School of Health, Medical and Applied Science, CQUniversity Australia, Rockhampton, Qld, Australia
| | - Glenn J Fitzgerald
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, Vic., Australia
- Agriculture Victoria, Horsham, Vic., Australia
| | | | | | - Michael Tausz
- Goods Shed North, CSIRO Data61, Docklands, Vic., Australia
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4
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Parvin S, Uddin S, Bourgault M, Delahunty A, Nuttall J, Brand J, O'Leary G, Fitzgerald GJ, Armstrong R, Tausz M. Effect of heat wave on N 2 fixation and N remobilisation of lentil (Lens culinaris MEDIK) grown under free air CO 2 enrichment in a mediterranean-type environment. Plant Biol (Stuttg) 2020; 22 Suppl 1:123-132. [PMID: 31532043 DOI: 10.1111/plb.13047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 09/06/2019] [Indexed: 05/14/2023]
Abstract
The stimulatory effect of elevated [CO2 ] (e[CO2 ]) on crop production in future climates is likely to be cancelled out by predicted increases in average temperatures. This effect may become stronger through more frequent and severe heat waves, which are predicted to increase in most climate change scenarios. Whilst the growth and yield response of some legumes grown under the interactive effect of e[CO2 ] and heat waves has been studied, little is known about how N2 fixation and overall N metabolism is affected by this combination. To address these knowledge gaps, two lentil genotypes were grown under ambient [CO2 ] (a[CO2 ], ~400 µmol·mol-1 ) and e[CO2 ] (~550 µmol·mol-1 ) in the Australian Grains Free Air CO2 Enrichment facility and exposed to a simulated heat wave (3-day periods of high temperatures ~40 °C) at flat pod stage. Nodulation and concentrations of water-soluble carbohydrates (WSC), total free amino acids, N and N2 fixation were assessed following the imposition of the heat wave until crop maturity. Elevated [CO2 ] stimulated N2 fixation so that total N2 fixation in e[CO2 ]-grown plants was always higher than in a[CO2 ], non-stressed control plants. Heat wave triggered a significant decrease in active nodules and WSC concentrations, but e[CO2 ] had the opposite effect. Leaf N remobilization and grain N improved under interaction of e[CO2 ] and heat wave. These results suggested that larger WSC pools and nodulation under e[CO2 ] can support post-heat wave recovery of N2 fixation. Elevated [CO2 ]-induced accelerated leaf N remobilisation might contribute to restore grain N concentration following a heat wave.
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Affiliation(s)
- S Parvin
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, Australia
- School of Ecosystem and Forest Sciences, The University of Melbourne, Creswick, Vic., Australia
- Department of Agronomy, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - S Uddin
- Department of Agronomy, Bangladesh Agricultural University, Mymensingh, Bangladesh
- NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, Australia
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, Vic., Australia
| | - M Bourgault
- Northern Agricultural Research Centre, Montana State University, Havre, MT, USA
| | - A Delahunty
- Agriculture Victoria Research, Horsham, Vic., Australia
| | - J Nuttall
- Agriculture Victoria Research, Horsham, Vic., Australia
| | - J Brand
- Agriculture Victoria Research, Horsham, Vic., Australia
| | - G O'Leary
- Agriculture Victoria Research, Horsham, Vic., Australia
| | - G J Fitzgerald
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, Vic., Australia
- Agriculture Victoria Research, Horsham, Vic., Australia
| | - R Armstrong
- Agriculture Victoria Research, Horsham, Vic., Australia
- Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Vic., Australia
| | - M Tausz
- Department of Agriculture, Science and the Environment, School of Health, Medical and Applied Science, CQUniversity Australia, Rockhampton, Qld, Australia
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5
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Asseng S, Martre P, Maiorano A, Rötter RP, O'Leary GJ, Fitzgerald GJ, Girousse C, Motzo R, Giunta F, Babar MA, Reynolds MP, Kheir AMS, Thorburn PJ, Waha K, Ruane AC, Aggarwal PK, Ahmed M, Balkovič J, Basso B, Biernath C, Bindi M, Cammarano D, Challinor AJ, De Sanctis G, Dumont B, Eyshi Rezaei E, Fereres E, Ferrise R, Garcia-Vila M, Gayler S, Gao Y, Horan H, Hoogenboom G, Izaurralde RC, Jabloun M, Jones CD, Kassie BT, Kersebaum KC, Klein C, Koehler AK, Liu B, Minoli S, Montesino San Martin M, Müller C, Naresh Kumar S, Nendel C, Olesen JE, Palosuo T, Porter JR, Priesack E, Ripoche D, Semenov MA, Stöckle C, Stratonovitch P, Streck T, Supit I, Tao F, Van der Velde M, Wallach D, Wang E, Webber H, Wolf J, Xiao L, Zhang Z, Zhao Z, Zhu Y, Ewert F. Climate change impact and adaptation for wheat protein. Glob Chang Biol 2019; 25:155-173. [PMID: 30549200 DOI: 10.1111/gcb.14481] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 09/06/2018] [Indexed: 05/20/2023]
Abstract
Wheat grain protein concentration is an important determinant of wheat quality for human nutrition that is often overlooked in efforts to improve crop production. We tested and applied a 32-multi-model ensemble to simulate global wheat yield and quality in a changing climate. Potential benefits of elevated atmospheric CO2 concentration by 2050 on global wheat grain and protein yield are likely to be negated by impacts from rising temperature and changes in rainfall, but with considerable disparities between regions. Grain and protein yields are expected to be lower and more variable in most low-rainfall regions, with nitrogen availability limiting growth stimulus from elevated CO2 . Introducing genotypes adapted to warmer temperatures (and also considering changes in CO2 and rainfall) could boost global wheat yield by 7% and protein yield by 2%, but grain protein concentration would be reduced by -1.1 percentage points, representing a relative change of -8.6%. Climate change adaptations that benefit grain yield are not always positive for grain quality, putting additional pressure on global wheat production.
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Affiliation(s)
- Senthold Asseng
- Agricultural & Biological Engineering Department, University of Florida, Gainesville, Florida
| | - Pierre Martre
- LEPSE, Université Montpellier INRA, Montpellier SupAgro, Montpellier, France
| | - Andrea Maiorano
- LEPSE, Université Montpellier INRA, Montpellier SupAgro, Montpellier, France
| | - Reimund P Rötter
- Tropical Plant Production and Agricultural Systems Modelling (TROPAGS), University of Göttingen, Göttingen, Germany
- Centre of Biodiversity and Sustainable Land Use (CBL), University of Göttingen, Göttingen, Germany
| | - Garry J O'Leary
- Department of Economic Development Jobs, Transport and Resources, Grains Innovation Park, Agriculture Victoria Research, Horsham, Victoria, Australia
| | - Glenn J Fitzgerald
- Department of Economic Development, Jobs, Transport and Resources, Agriculture Victoria Research, Horsham, Victoria, Australia
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, Victoria, Australia
| | | | - Rosella Motzo
- Department of Agricultural Sciences, University of Sassari, Sassari, Italy
| | - Francesco Giunta
- Department of Agricultural Sciences, University of Sassari, Sassari, Italy
| | - M Ali Babar
- World Food Crops Breeding, Department of Agronomy, IFAS, University of Florida, Gainesville, Florida
| | | | - Ahmed M S Kheir
- Soils, Water and Environment Research Institute, Agricultural Research Center, Giza, Egypt
| | | | - Katharina Waha
- CSIRO Agriculture and Food, Brisbane, Queensland, Australia
| | - Alex C Ruane
- NASA Goddard Institute for Space Studies, New York, New York
| | - Pramod K Aggarwal
- CGIAR Research Program on Climate Change, Agriculture and Food Security, BISA-CIMMYT, New Delhi, India
| | - Mukhtar Ahmed
- Biological Systems Engineering, Washington State University, Pullman, Washington
- Department of Agronomy, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan
| | - Juraj Balkovič
- International Institute for Applied Systems Analysis, Ecosystem Services and Management Program, Laxenburg, Austria
- Department of Soil Science, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Bruno Basso
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, Michigan
- W.K. Kellogg Biological Station, Michigan State University, East Lansing, Michigan
| | - Christian Biernath
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Marco Bindi
- Department of Agri-food Production and Environmental Sciences (DISPAA), University of Florence, Florence, Italy
| | | | - Andrew J Challinor
- Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
- Collaborative Research Program from CGIAR and Future Earth on Climate Change, Agriculture and Food Security (CCAFS), International Centre for Tropical Agriculture (CIAT), Cali, Colombia
| | | | - Benjamin Dumont
- Department Terra & AgroBioChem, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium
| | - Ehsan Eyshi Rezaei
- Institute of Crop Science and Resource Conservation INRES, University of Bonn, Bonn, Germany
- Department of Crop Sciences, University of Göttingen, Göttingen, Germany
| | | | - Roberto Ferrise
- Department of Agri-food Production and Environmental Sciences (DISPAA), University of Florence, Florence, Italy
| | | | - Sebastian Gayler
- Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
| | - Yujing Gao
- Agricultural & Biological Engineering Department, University of Florida, Gainesville, Florida
| | - Heidi Horan
- CSIRO Agriculture and Food, Brisbane, Queensland, Australia
| | - Gerrit Hoogenboom
- Agricultural & Biological Engineering Department, University of Florida, Gainesville, Florida
- Institute for Sustainable Food Systems, University of Florida, Gainesville, Florida
| | - R César Izaurralde
- Department of Geographical Sciences, University of Maryland, College Park, Maryland
- Texas A&M AgriLife Research and Extension Center, Texas A&M University, Temple, Texas
| | - Mohamed Jabloun
- Department of Agroecology, Aarhus University, Tjele, Denmark
| | - Curtis D Jones
- Department of Geographical Sciences, University of Maryland, College Park, Maryland
| | - Belay T Kassie
- Agricultural & Biological Engineering Department, University of Florida, Gainesville, Florida
| | | | - Christian Klein
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Ann-Kristin Koehler
- Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
| | - Bing Liu
- Agricultural & Biological Engineering Department, University of Florida, Gainesville, Florida
- National Engineering and Technology Center for Information Agriculture, Key Laboratory for Crop System Analysis and Decision Making, Ministry of Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, China
| | - Sara Minoli
- Potsdam Institute for Climate Impact Research, Member of the Leibniz Association, Potsdam, Germany
| | | | - Christoph Müller
- Potsdam Institute for Climate Impact Research, Member of the Leibniz Association, Potsdam, Germany
| | - Soora Naresh Kumar
- Centre for Environment Science and Climate Resilient Agriculture, Indian Agricultural Research Institute, IARI PUSA, New Delhi, India
| | - Claas Nendel
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | | | - Taru Palosuo
- Montpellier SupAgro, INRA, CIHEAM-IAMM, CIRAD, University Montpellier, Montpellier, France
| | - John R Porter
- Plant & Environment Sciences, University Copenhagen, Taastrup, Denmark
- Lincoln University, Lincoln, New Zealand
- Montpellier SupAgro, INRA, CIHEAM-IAMM, CIRAD, University Montpellier, Montpellier, France
| | - Eckart Priesack
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | | | | | - Claudio Stöckle
- Biological Systems Engineering, Washington State University, Pullman, Washington
| | | | - Thilo Streck
- Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
| | - Iwan Supit
- Water & Food and Water Systems & Global Change Group, Wageningen University, Wageningen, The Netherlands
| | - Fulu Tao
- Natural Resources Institute Finland (Luke), Helsinki, Finland
- Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Science, Beijing, China
| | | | | | - Enli Wang
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia
| | - Heidi Webber
- Institute of Crop Science and Resource Conservation INRES, University of Bonn, Bonn, Germany
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Joost Wolf
- Plant Production Systems, Wageningen University, Wageningen, The Netherlands
| | - Liujun Xiao
- National Engineering and Technology Center for Information Agriculture, Key Laboratory for Crop System Analysis and Decision Making, Ministry of Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, China
| | - Zhao Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Zhigan Zhao
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia
- Department of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Yan Zhu
- National Engineering and Technology Center for Information Agriculture, Key Laboratory for Crop System Analysis and Decision Making, Ministry of Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, China
| | - Frank Ewert
- Institute of Crop Science and Resource Conservation INRES, University of Bonn, Bonn, Germany
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
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6
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Wallach D, Martre P, Liu B, Asseng S, Ewert F, Thorburn PJ, van Ittersum M, Aggarwal PK, Ahmed M, Basso B, Biernath C, Cammarano D, Challinor AJ, De Sanctis G, Dumont B, Eyshi Rezaei E, Fereres E, Fitzgerald GJ, Gao Y, Garcia-Vila M, Gayler S, Girousse C, Hoogenboom G, Horan H, Izaurralde RC, Jones CD, Kassie BT, Kersebaum KC, Klein C, Koehler AK, Maiorano A, Minoli S, Müller C, Naresh Kumar S, Nendel C, O'Leary GJ, Palosuo T, Priesack E, Ripoche D, Rötter RP, Semenov MA, Stöckle C, Stratonovitch P, Streck T, Supit I, Tao F, Wolf J, Zhang Z. Multimodel ensembles improve predictions of crop-environment-management interactions. Glob Chang Biol 2018; 24:5072-5083. [PMID: 30055118 DOI: 10.1111/gcb.14411] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 07/01/2018] [Accepted: 07/05/2018] [Indexed: 06/08/2023]
Abstract
A recent innovation in assessment of climate change impact on agricultural production has been to use crop multimodel ensembles (MMEs). These studies usually find large variability between individual models but that the ensemble mean (e-mean) and median (e-median) often seem to predict quite well. However, few studies have specifically been concerned with the predictive quality of those ensemble predictors. We ask what is the predictive quality of e-mean and e-median, and how does that depend on the ensemble characteristics. Our empirical results are based on five MME studies applied to wheat, using different data sets but the same 25 crop models. We show that the ensemble predictors have quite high skill and are better than most and sometimes all individual models for most groups of environments and most response variables. Mean squared error of e-mean decreases monotonically with the size of the ensemble if models are added at random, but has a minimum at usually 2-6 models if best-fit models are added first. Our theoretical results describe the ensemble using four parameters: average bias, model effect variance, environment effect variance, and interaction variance. We show analytically that mean squared error of prediction (MSEP) of e-mean will always be smaller than MSEP averaged over models and will be less than MSEP of the best model if squared bias is less than the interaction variance. If models are added to the ensemble at random, MSEP of e-mean will decrease as the inverse of ensemble size, with a minimum equal to squared bias plus interaction variance. This minimum value is not necessarily small, and so it is important to evaluate the predictive quality of e-mean for each target population of environments. These results provide new information on the advantages of ensemble predictors, but also show their limitations.
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Affiliation(s)
| | - Pierre Martre
- UMR LEPSE, INRA, Montpellier SupAgro, Montpellier, France
| | - Bing Liu
- National Engineering and Technology Center for Information Agriculture, Key Laboratory for Crop System Analysis and Decision Making, Ministry of Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, Jiangsu, China
- Agricultural and Biological Engineering Department, University of Florida, Gainesville, Florida
| | - Senthold Asseng
- Agricultural and Biological Engineering Department, University of Florida, Gainesville, Florida
| | - Frank Ewert
- Institute of Crop Science and Resource Conservation INRES, University of, Bonn, Germany
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Peter J Thorburn
- CSIRO Agriculture and Food Brisbane, St Lucia, Queensland, Australia
| | - Martin van Ittersum
- Plant Production Systems Group, Wageningen University, Wageningen, The Netherlands
| | - Pramod K Aggarwal
- CGIAR Research Program on Climate Change, Agriculture and Food Security, BISA-CIMMYT, New Delhi, India
| | - Mukhtar Ahmed
- Biological Systems Engineering, Washington State University, Pullman, Washington
- Department of Agronomy, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan
| | - Bruno Basso
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, Michigan
- W.K. Kellogg Biological Station, Michigan State University, East Lansing, Michigan
| | - Christian Biernath
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | | | - Andrew J Challinor
- Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
- CGIAR-ESSP Program on Climate Change, Agriculture and Food Security, International Centre for Tropical Agriculture (CIAT), Cali, Colombia
| | | | - Benjamin Dumont
- Department Terra & AgroBioChem, Gembloux Agro-Bio Tech, University of Liege, Liege, Belgium
| | - Ehsan Eyshi Rezaei
- Institute of Crop Science and Resource Conservation INRES, University of, Bonn, Germany
- Center for Development Research (ZEF), Bonn, Germany
| | | | - Glenn J Fitzgerald
- Agriculture Victoria Research, Department of Economic Development, Jobs, Transport and Resources, Ballarat, Victoria, Australia
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, Victoria, Australia
| | - Y Gao
- Agricultural and Biological Engineering Department, University of Florida, Gainesville, Florida
| | | | - Sebastian Gayler
- Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
| | | | - Gerrit Hoogenboom
- Agricultural and Biological Engineering Department, University of Florida, Gainesville, Florida
- Institute for Sustainable Food Systems, University of Florida, Gainesville, Florida
| | - Heidi Horan
- CSIRO Agriculture and Food Brisbane, St Lucia, Queensland, Australia
| | - Roberto C Izaurralde
- Department of Geographical Sciences, University of Maryland, College Park, Maryland
- Texas A&M AgriLife Research and Extension Center, Texas A&M University, Temple, Texas
| | - Curtis D Jones
- Texas A&M AgriLife Research and Extension Center, Texas A&M University, Temple, Texas
| | - Belay T Kassie
- Agricultural and Biological Engineering Department, University of Florida, Gainesville, Florida
| | - Kurt C Kersebaum
- Institute of Landscape Systems Analysis, Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Christian Klein
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Ann-Kristin Koehler
- Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
| | | | - Sara Minoli
- Potsdam Institute for Climate Impact Research, Potsdam, Germany
| | | | - Soora Naresh Kumar
- Centre for Environment Science and Climate Resilient Agriculture, Indian Agricultural Research Institute, IARI PUSA, New Delhi, India
| | - Claas Nendel
- Institute of Landscape Systems Analysis, Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Garry J O'Leary
- Grains Innovation Park, Department of Economic Development, Jobs, Transport and Resources, Agriculture Victoria Research, Horsham, Victoria, Australia
| | - Taru Palosuo
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Eckart Priesack
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | | | - Reimund P Rötter
- Tropical Plant Production and Agricultural Systems Modelling (TROPAGS), University of Göttingen, Göttingen, Germany
- Centre of Biodiversity and Sustainable Land Use (CBL), University of Göttingen, Göttingen, Germany
| | - Mikhail A Semenov
- Computational and Systems Biology Department, Rothamsted Research, Harpenden, Herts, UK
| | - Claudio Stöckle
- Biological Systems Engineering, Washington State University, Pullman, Washington
| | - Pierre Stratonovitch
- Computational and Systems Biology Department, Rothamsted Research, Harpenden, Herts, UK
| | - Thilo Streck
- Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
| | - Iwan Supit
- Water & Food and Water Systems & Global Change Group, Wageningen University, Wageningen, The Netherlands
| | - Fulu Tao
- Natural Resources Institute Finland (Luke), Helsinki, Finland
- Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Science, Beijing, China
| | - Joost Wolf
- Plant Production Systems, Wageningen University, Wageningen, The Netherlands
| | - Zhao Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China
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7
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Uddin S, Parvin S, Löw M, Fitzgerald GJ, Tausz-Posch S, Armstrong R, Tausz M. The water use dynamics of canola cultivars grown under elevated CO 2 are linked to their leaf area development. J Plant Physiol 2018; 229:164-169. [PMID: 30103086 DOI: 10.1016/j.jplph.2018.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/30/2018] [Accepted: 08/03/2018] [Indexed: 06/08/2023]
Abstract
The 'CO2 fertilisation effect' is often predicted to be greater under drier than wetter conditions, mainly due to hypothesised early season water savings under elevated [CO2] (e[CO2]). However, water savings largely depend on the balance between CO2-induced improvement of leaf-level water use efficiency and CO2-stimulation of transpiring leaf area. The dynamics of water use during the growing season can therefore vary depending on leaf area development. Two canola (Brassica napus L.) cultivars of contrasting growth and vigour (vigorous hybrid cv. Hyola 50 and non-hybrid cv. Thumper) were grown under ambient [CO2] (a[CO2], ∼400 μmol mol-1) or e[CO2] (∼700 μmol mol-1) with two water treatments (well-watered and mild drought) in a glasshouse to investigate the interdependence of leaf area development and water use. Dynamics of water use during the growing season varied depending on [CO2] and cultivars. Early stimulation of leaf growth under e[CO2], which also depended on cultivar, overcompensated for the effect of increased leaf-level water use efficiency, so that weekly water use was greater and water depletion from soil greater under e[CO2] than a[CO2]. This result shows that the balance between leaf area and water use efficiency stimulation by e[CO2] can tip towards early depletion of available soil water, so that e[CO2] does not lead to water savings, and the 'CO2 fertilisation effect' is not greater under drier conditions.
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Affiliation(s)
- Shihab Uddin
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia; Department of Agronomy, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh.
| | - Shahnaj Parvin
- Department of Agronomy, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh; School of Ecosystem and Forest Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia
| | - Markus Löw
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia
| | - Glenn J Fitzgerald
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia; Department of Economic Development, Jobs, Transport and Resources, Private Bag 260, Horsham, VIC 3401, Australia
| | - Sabine Tausz-Posch
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia; School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Roger Armstrong
- Department of Economic Development, Jobs, Transport and Resources, Private Bag 260, Horsham, VIC 3401, Australia; Department of Animal, Plant and Soil Sciences, Centre for AgriBioscience, La Trobe University, Bundoora, VIC 3086, Australia
| | - Michael Tausz
- School of Ecosystem and Forest Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia; Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
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8
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Houshmandfar A, Fitzgerald GJ, O'Leary G, Tausz-Posch S, Fletcher A, Tausz M. The relationship between transpiration and nutrient uptake in wheat changes under elevated atmospheric CO 2. Physiol Plant 2018; 163:516-529. [PMID: 29205382 DOI: 10.1111/ppl.12676] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/20/2017] [Indexed: 05/26/2023]
Abstract
The impact of elevated [CO2 ] (e[CO2 ]) on crops often includes a decrease in their nutrient concentrations where reduced transpiration-driven mass flow of nutrients has been suggested to play a role. We used two independent approaches, a free-air CO2 enrichment (FACE) experiment in the South Eastern wheat belt of Australia and a simulation study employing the agricultural production systems simulator (APSIM), to show that transpiration (mm) and nutrient uptake (g m-2 ) of nitrogen (N), potassium (K), sulfur (S), calcium (Ca), magnesium (Mg) and manganese (Mn) in wheat are correlated under e[CO2 ], but that nutrient uptake per unit water transpired is higher under e[CO2 ] than under ambient [CO2 ] (a[CO2 ]). This result suggests that transpiration-driven mass flow of nutrients contributes to decreases in nutrient concentrations under e[CO2 ], but cannot solely explain the overall decline.
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Affiliation(s)
- Alireza Houshmandfar
- CSIRO Agriculture and Food, Private Bag 5, P.O., Wembley, WA, 6913, Australia
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Creswick, VIC, 3363, Australia
| | - Glenn J Fitzgerald
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Creswick, VIC, 3363, Australia
- Agriculture Victoria, Victoria State Department of Economic Development, Jobs, Transport and Resources, Horsham, 3401, Australia
| | - Garry O'Leary
- Agriculture Victoria, Victoria State Department of Economic Development, Jobs, Transport and Resources, Horsham, 3401, Australia
| | - Sabine Tausz-Posch
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Creswick, VIC, 3363, Australia
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Andrew Fletcher
- CSIRO Agriculture and Food, Private Bag 5, P.O., Wembley, WA, 6913, Australia
| | - Michael Tausz
- Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Department of Ecosystem and Forest Sciences, University of Melbourne, Creswick, Victoria, 3363, Australia
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9
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Uddin S, Löw M, Parvin S, Fitzgerald GJ, Tausz-Posch S, Armstrong R, O’Leary G, Tausz M. Elevated [CO2] mitigates the effect of surface drought by stimulating root growth to access sub-soil water. PLoS One 2018; 13:e0198928. [PMID: 29902235 PMCID: PMC6002051 DOI: 10.1371/journal.pone.0198928] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 05/29/2018] [Indexed: 01/26/2023] Open
Abstract
Through stimulation of root growth, increasing atmospheric CO2 concentration ([CO2]) may facilitate access of crops to sub-soil water, which could potentially prolong physiological activity in dryland environments, particularly because crops are more water use efficient under elevated [CO2] (e[CO2]). This study investigated the effect of drought in shallow soil versus sub-soil on agronomic and physiological responses of wheat to e[CO2] in a glasshouse experiment. Wheat (Triticum aestivum L. cv. Yitpi) was grown in split-columns with the top (0-30 cm) and bottom (31-60 cm; 'sub-soil') soil layer hydraulically separated by a wax-coated, root-penetrable layer under ambient [CO2] (a[CO2], ∼400 μmol mol-1) or e[CO2] (∼700 μmol mol-1) [CO2]. Drought was imposed from stem-elongation in either the top or bottom soil layer or both by withholding 33% of the irrigation, resulting in four water treatments (WW, WD, DW, DD; D = drought, W = well-watered, letters denote water treatment in top and bottom soil layer, respectively). Leaf gas exchange was measured weekly from stem-elongation until anthesis. Above-and belowground biomass, grain yield and yield components were evaluated at three developmental stages (stem-elongation, anthesis and maturity). Compared with a[CO2], net assimilation rate was higher and stomatal conductance was lower under e[CO2], resulting in greater intrinsic water use efficiency. Elevated [CO2] stimulated both above- and belowground biomass as well as grain yield, however, this stimulation was greater under well-watered (WW) than drought (DD) throughout the whole soil profile. Imposition of drought in either or both soil layers decreased aboveground biomass and grain yield under both [CO2] compared to the well-watered treatment. However, the greatest 'CO2 fertilisation effect' was observed when drought was imposed in the top soil layer only (DW), and this was associated with e[CO2]-stimulation of root growth especially in the well-watered bottom layer. We suggest that stimulation of belowground biomass under e[CO2] will allow better access to sub-soil water during grain filling period, when additional water is converted into additional yield with high efficiency in Mediterranean-type dryland agro-ecosystems. If sufficient water is available in the sub-soil, e[CO2] may help mitigating the effect of drying surface soil.
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Affiliation(s)
- Shihab Uddin
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, Victoria, Australia
- Department of Agronomy, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Markus Löw
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, Victoria, Australia
| | - Shahnaj Parvin
- Department of Agronomy, Bangladesh Agricultural University, Mymensingh, Bangladesh
- School of Ecosystem and Forest Sciences, The University of Melbourne, Creswick, Victoria, Australia
| | - Glenn J. Fitzgerald
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, Victoria, Australia
- Department of Economic Development, Jobs, Transport and Resources, Horsham, Victoria, Australia
| | - Sabine Tausz-Posch
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, Victoria, Australia
| | - Roger Armstrong
- Department of Economic Development, Jobs, Transport and Resources, Horsham, Victoria, Australia
- Department of Animal, Plant and Soil Sciences, Centre for AgriBioscience, La Trobe University, Bundoora, Victoria, Australia
| | - Garry O’Leary
- Department of Economic Development, Jobs, Transport and Resources, Horsham, Victoria, Australia
| | - Michael Tausz
- School of Ecosystem and Forest Sciences, The University of Melbourne, Creswick, Victoria, Australia
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10
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Bahrami H, De Kok LJ, Armstrong R, Fitzgerald GJ, Bourgault M, Henty S, Tausz M, Tausz-Posch S. The proportion of nitrate in leaf nitrogen, but not changes in root growth, are associated with decreased grain protein in wheat under elevated [CO 2]. J Plant Physiol 2017; 216:44-51. [PMID: 28575746 DOI: 10.1016/j.jplph.2017.05.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 05/26/2023]
Abstract
The atmospheric CO2 concentration ([CO2]) is increasing and predicted to reach ∼550ppm by 2050. Increasing [CO2] typically stimulates crop growth and yield, but decreases concentrations of nutrients, such as nitrogen ([N]), and therefore protein, in plant tissues and grains. Such changes in grain composition are expected to have negative implications for the nutritional and economic value of grains. This study addresses two mechanisms potentially accountable for the phenomenon of elevated [CO2]-induced decreases in [N]: N uptake per unit length of roots as well as inhibition of the assimilation of nitrate (NO3-) into protein are investigated and related to grain protein. We analysed two wheat cultivars from a similar genetic background but contrasting in agronomic features (Triticum aestivum L. cv. Scout and Yitpi). Plants were field-grown within the Australian Grains Free Air CO2 Enrichment (AGFACE) facility under two atmospheric [CO2] (ambient, ∼400ppm, and elevated, ∼550ppm) and two water treatments (rain-fed and well-watered). Aboveground dry weight (ADW) and root length (RL, captured by a mini-rhizotron root growth monitoring system), as well as [N] and NO3- concentrations ([NO3-]) were monitored throughout the growing season and related to grain protein at harvest. RL generally increased under e[CO2] and varied between water supply and cultivars. The ratio of total aboveground N (TN) taken up per RL was affected by CO2 treatment only later in the season and there was no significant correlation between TN/RL and grain protein concentration across cultivars and [CO2] treatments. In contrast, a greater percentage of N remained as unassimilated [NO3-] in the tissue of e[CO2] grown crops (expressed as the ratio of NO3- to total N) and this was significantly correlated with decreased grain protein. These findings suggest that e[CO2] directly affects the nitrate assimilation capacity of wheat with direct negative implications for grain quality.
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Affiliation(s)
- Helale Bahrami
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, 3363 Victoria, Australia
| | - Luit J De Kok
- Laboratory of Plant Physiology, University of Groningen, 9747 AG Groningen, The Netherlands; Department of Ecosystem and Forest Sciences, The University of Melbourne, Creswick, 3363 Victoria, Australia
| | - Roger Armstrong
- Department of Economic Development, Jobs, Transport & Resources, Horsham, 3401 Victoria, Australia; Department of Animal, Plant & Soil Sciences, La Trobe University, 3086 Victoria, Australia
| | - Glenn J Fitzgerald
- Department of Economic Development, Jobs, Transport & Resources, Horsham, 3401 Victoria, Australia
| | - Maryse Bourgault
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, 3363 Victoria, Australia; Northern Agricultural Research Center, Montana State University, Havre, MT, USA
| | - Samuel Henty
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, 3363 Victoria, Australia
| | - Michael Tausz
- Department of Ecosystem and Forest Sciences, The University of Melbourne, Creswick, 3363 Victoria, Australia; School of Biosciences, University of Birmingham, Edgbaston, Birmingham B152TT, UK
| | - Sabine Tausz-Posch
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, 3363 Victoria, Australia; School of Biosciences, University of Birmingham, Edgbaston, Birmingham B152TT, UK.
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11
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Trębicki P, Nancarrow N, Bosque-Pérez NA, Rodoni B, Aftab M, Freeman A, Yen A, Fitzgerald GJ. Virus incidence in wheat increases under elevated CO 2: A 4-year study of yellow dwarf viruses from a free air carbon dioxide facility. Virus Res 2017; 241:137-144. [PMID: 28684156 DOI: 10.1016/j.virusres.2017.06.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/05/2017] [Accepted: 06/26/2017] [Indexed: 11/19/2022]
Abstract
The complexities behind the mechanisms associated with virus-host-vector interactions of vector-transmitted viruses, and their consequences for disease development need to be understood to reduce virus spread and disease severity. Climate has a substantial effect on viruses, vectors, host plants and their interactions. Increased atmospheric carbon dioxide (CO2) is predicted to impact the interactions between them. This study, conducted under ambient and elevated CO2 (550μmolmol-1), in the Australian Grains Free Air Carbon Enrichment facility reports on natural yellow dwarf virus incidence on wheat (including Barley/Cereal yellow dwarf viruses (B/CYDV)). A range of wheat cultivars was tested using tissue blot immunoassay to determine the incidence of four yellow dwarf virus species from 2013 to 2016. In 2013, 2014 and 2016, virus incidence was high, reaching upwards of 50%, while in 2015 it was relatively low, with a maximum incidence of 3%. Across all years and most cultivars, BYDV-PAV was the most prevalent virus species. In the years with high virus incidence, a majority plots with the elevated levels of CO2 (eCO2) were associated with increased levels of virus relative to the plots with ambient CO2. In 2013, 2014 and 2016 the recorded mean percent virus incidence was higher under elevated CO2 when compared to ambient CO2 by 33%, 14% and 34%, respectively. The mechanism behind increased yellow dwarf virus incidence under elevated CO2 is not well understood. Potential factors involved in the higher virus incidence under elevated CO2 conditions are discussed.
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Affiliation(s)
- Piotr Trębicki
- Biosciences Research, Department of Economic Development Jobs, Transport and Resources, (DEDJTR), 110 Natimuk Rd, Horsham, VIC, 3400, Australia.
| | - Narelle Nancarrow
- Biosciences Research, Department of Economic Development Jobs, Transport and Resources, (DEDJTR), 110 Natimuk Rd, Horsham, VIC, 3400, Australia
| | - Nilsa A Bosque-Pérez
- Department of Plant, Soil and Entomological Sciences, University of Idaho,875 Perimeter Drive MS 2339, Moscow, ID 83844-2339, USA
| | - Brendan Rodoni
- Biosciences Research, DEDJTR, AgriBio Centre,5 Ring Road, La Trobe University, Bundoora, VIC, 3083, Australia
| | - Mohammad Aftab
- Biosciences Research, Department of Economic Development Jobs, Transport and Resources, (DEDJTR), 110 Natimuk Rd, Horsham, VIC, 3400, Australia
| | - Angela Freeman
- Biosciences Research, DEDJTR, AgriBio Centre,5 Ring Road, La Trobe University, Bundoora, VIC, 3083, Australia
| | - Alan Yen
- Biosciences Research, DEDJTR, AgriBio Centre,5 Ring Road, La Trobe University, Bundoora, VIC, 3083, Australia
| | - Glenn J Fitzgerald
- DEDJTR, Agricultural Research, 402-404 Mair St, Ballarat, Victoria, 3350, Australia; Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick Victoria 3363, Australia
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12
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Fitzgerald GJ, Tausz M, O'Leary G, Mollah MR, Tausz-Posch S, Seneweera S, Mock I, Löw M, Partington DL, McNeil D, Norton RM. Elevated atmospheric [CO2 ] can dramatically increase wheat yields in semi-arid environments and buffer against heat waves. Glob Chang Biol 2016; 22:2269-84. [PMID: 28715112 DOI: 10.1111/gcb.13263] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 02/07/2016] [Accepted: 02/10/2016] [Indexed: 05/03/2023]
Abstract
Wheat production will be impacted by increasing concentration of atmospheric CO2 [CO2 ], which is expected to rise from about 400 μmol mol(-1) in 2015 to 550 μmol mol(-1) by 2050. Changes to plant physiology and crop responses from elevated [CO2 ] (e[CO2 ]) are well documented for some environments, but field-level responses in dryland Mediterranean environments with terminal drought and heat waves are scarce. The Australian Grains Free Air CO2 Enrichment facility was established to compare wheat (Triticum aestivum) growth and yield under ambient (~370 μmol(-1) in 2007) and e[CO2 ] (550 μmol(-1) ) in semi-arid environments. Experiments were undertaken at two dryland sites (Horsham and Walpeup) across three years with two cultivars, two sowing times and two irrigation treatments. Mean yield stimulation due to e[CO2 ] was 24% at Horsham and 53% at Walpeup, with some treatment responses greater than 70%, depending on environment. Under supplemental irrigation, e[CO2 ] stimulated yields at Horsham by 37% compared to 13% under rainfed conditions, showing that water limited growth and yield response to e[CO2 ]. Heat wave effects were ameliorated under e[CO2 ] as shown by reductions of 31% and 54% in screenings and 10% and 12% larger kernels (Horsham and Walpeup). Greatest yield stimulations occurred in the e[CO2 ] late sowing and heat stressed treatments, when supplied with more water. There were no clear differences in cultivar response due to e[CO2 ]. Multiple regression showed that yield response to e[CO2 ] depended on temperatures and water availability before and after anthesis. Thus, timing of temperature and water and the crop's ability to translocate carbohydrates to the grain postanthesis were all important in determining the e[CO2 ] response. The large responses to e[CO2 ] under dryland conditions have not been previously reported and underscore the need for field level research to provide mechanistic understanding for adapting crops to a changing climate.
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Affiliation(s)
- Glenn J Fitzgerald
- Victorian Department of Economic Development, Jobs, Transport and Resources, Private Bag 260, Horsham, Vic., 3401, Australia
| | - Michael Tausz
- Department of Forest and Ecosystem Science, The University of Melbourne, 4 Water Street, Creswick, Vic., 3363, Australia
| | - Garry O'Leary
- Victorian Department of Economic Development, Jobs, Transport and Resources, Private Bag 260, Horsham, Vic., 3401, Australia
| | - Mahabubur R Mollah
- Victorian Department of Economic Development, Jobs, Transport and Resources, Private Bag 260, Horsham, Vic., 3401, Australia
| | - Sabine Tausz-Posch
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, Vic., 3363, Australia
| | - Saman Seneweera
- Centre for Crop Health, University of Southern Queensland, Toowoomba, Qld, 4350, Australia
| | - Ivan Mock
- Victorian Department of Economic Development, Jobs, Transport and Resources, Private Bag 260, Horsham, Vic., 3401, Australia
- Dodgshun Medlin Agricultural Management, 348 Campbell St, Swan Hill, Vic., 3585, Australia
| | - Markus Löw
- Department of Forest and Ecosystem Science, The University of Melbourne, 4 Water Street, Creswick, Vic., 3363, Australia
| | - Debra L Partington
- Victorian Department of Economic Development, Jobs, Transport and Resources, Hamilton Centre, Mount Napier Road, Hamilton, Vic., 3300, Australia
| | - David McNeil
- Tasmanian Institute of Agriculture, Private Bag 98, Hobart, Tas., 7001, Australia
| | - Robert M Norton
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, Vic., 3363, Australia
- International Plant Nutrition Institute, 54 Florence St, Horsham, Vic., Australia
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13
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Trębicki P, Vandegeer RK, Bosque-Pérez NA, Powell KS, Dader B, Freeman AJ, Yen AL, Fitzgerald GJ, Luck JE. Virus infection mediates the effects of elevated CO2 on plants and vectors. Sci Rep 2016; 6:22785. [PMID: 26941044 PMCID: PMC4778167 DOI: 10.1038/srep22785] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/19/2016] [Indexed: 11/16/2022] Open
Abstract
Atmospheric carbon dioxide (CO2) concentration has increased significantly and is projected to double by 2100. To increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing CO2 is imperative. We investigated the effects of elevated CO2 (eCO2) on the interactions among wheat (cv. Yitpi), Barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (Rhopalosiphum padi), by examining aphid life history, feeding behavior and plant physiology and biochemistry. Our results showed for the first time that virus infection can mediate effects of eCO2 on plants and pathogen vectors. Changes in plant N concentration influenced aphid life history and behavior, and N concentration was affected by virus infection under eCO2. We observed a reduction in aphid population size and increased feeding damage on noninfected plants under eCO2 but no changes to population and feeding on virus-infected plants irrespective of CO2 treatment. We expect potentially lower future aphid populations on noninfected plants but no change or increased aphid populations on virus-infected plants therefore subsequent virus spread. Our findings underscore the complexity of interactions between plants, insects and viruses under future climate with implications for plant disease epidemiology and crop production.
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Affiliation(s)
- Piotr Trębicki
- Biosciences Research, Department of Economic Development, (DED), 110 Natimuk Rd, Horsham, VIC, 3400, Australia
| | - Rebecca K Vandegeer
- Biosciences Research, DED, 5 Ring Road, La Trobe University, Bundoora, VIC, 3083, Australia
| | - Nilsa A Bosque-Pérez
- Department of Plant, Soil and Entomological Sciences, University of Idaho, 875 Perimeter Drive, MS 2339, Moscow, ID 83844-2339 USA
| | - Kevin S Powell
- Biosciences Research, DED, 124, Chiltern Valley Road, Rutherglen, VIC, 3685, Australia
| | - Beatriz Dader
- Biosciences Research, Department of Economic Development, (DED), 110 Natimuk Rd, Horsham, VIC, 3400, Australia.,Institute of Agricultural Sciences-CSIC, Calle Serrano 115 dpdo., 28006, Madrid, Spain
| | - Angela J Freeman
- Biosciences Research, DED, 5 Ring Road, La Trobe University, Bundoora, VIC, 3083, Australia
| | - Alan L Yen
- Biosciences Research, DED, 5 Ring Road, La Trobe University, Bundoora, VIC, 3083, Australia
| | - Glenn J Fitzgerald
- Agriculture Research, DED, 110 Natimuk Rd, Horsham, VIC, 3400, Australia
| | - Jo E Luck
- Plant Biosecurity Cooperative Research Centre, LPO Box 5012, Bruce ACT, Australia
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14
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Trębicki P, Nancarrow N, Cole E, Bosque-Pérez NA, Constable FE, Freeman AJ, Rodoni B, Yen AL, Luck JE, Fitzgerald GJ. Virus disease in wheat predicted to increase with a changing climate. Glob Chang Biol 2015; 21:3511-3519. [PMID: 25846559 DOI: 10.1111/gcb.12941] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/28/2015] [Accepted: 03/30/2015] [Indexed: 06/04/2023]
Abstract
Current atmospheric CO2 levels are about 400 μmol mol(-1) and are predicted to rise to 650 μmol mol(-1) later this century. Although the positive and negative impacts of CO2 on plants are well documented, little is known about interactions with pests and diseases. If disease severity increases under future environmental conditions, then it becomes imperative to understand the impacts of pathogens on crop production in order to minimize crop losses and maximize food production. Barley yellow dwarf virus (BYDV) adversely affects the yield and quality of economically important crops including wheat, barley and oats. It is transmitted by numerous aphid species and causes a serious disease of cereal crops worldwide. This study examined the effects of ambient (aCO2 ; 400 μmol mol(-1) ) and elevated CO2 (eCO2 ; 650 μmol mol(-1) ) on noninfected and BYDV-infected wheat. Using a RT-qPCR technique, we measured virus titre from aCO2 and eCO2 treatments. BYDV titre increased significantly by 36.8% in leaves of wheat grown under eCO2 conditions compared to aCO2 . Plant growth parameters including height, tiller number, leaf area and biomass were generally higher in plants exposed to higher CO2 levels but increased growth did not explain the increase in BYDV titre in these plants. High virus titre in plants has been shown to have a significant negative effect on plant yield and causes earlier and more pronounced symptom expression increasing the probability of virus spread by insects. The combination of these factors could negatively impact food production in Australia and worldwide under future climate conditions. This is the first quantitative evidence that BYDV titre increases in plants grown under elevated CO2 levels.
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Affiliation(s)
- Piotr Trębicki
- Biosciences Research Division, Department of Economic Development, (DED), 110 Natimuk Rd, Horsham, Vic., 3400, Australia
| | - Narelle Nancarrow
- Biosciences Research Division, DED, La Trobe University, 5 Ring Road, Bundoora, Vic., 3083, Australia
| | - Ellen Cole
- Department of Biology, Loyola University Chicago, 1032 West Sheridan Road, Chicago, IL, 60660, USA
| | - Nilsa A Bosque-Pérez
- Department of Plant, Soil and Entomological Sciences, University of Idaho, 875 Perimeter Drive MS 2339, Moscow, ID, 83844-2339, USA
| | - Fiona E Constable
- Biosciences Research Division, DED, La Trobe University, 5 Ring Road, Bundoora, Vic., 3083, Australia
| | - Angela J Freeman
- Biosciences Research Division, Department of Economic Development, (DED), 110 Natimuk Rd, Horsham, Vic., 3400, Australia
| | - Brendan Rodoni
- Biosciences Research Division, DED, La Trobe University, 5 Ring Road, Bundoora, Vic., 3083, Australia
| | - Alan L Yen
- Biosciences Research Division, DED, La Trobe University, 5 Ring Road, Bundoora, Vic., 3083, Australia
- School of Applied Systems Biology, La Trobe University, Bundoora, Vic., 3083, Australia
| | - Jo E Luck
- Plant Biosecurity Cooperative Research Centre, LPO Box 5012, Bruce, ACT, Australia
| | - Glenn J Fitzgerald
- Agriculture Research Division, DED, 110 Natimuk Rd, Horsham, Vic., 3400, Australia
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15
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Buchner P, Tausz M, Ford R, Leo A, Fitzgerald GJ, Hawkesford MJ, Tausz-Posch S. Expression patterns of C- and N-metabolism related genes in wheat are changed during senescence under elevated CO2 in dry-land agriculture. Plant Sci 2015; 236:239-249. [PMID: 26025537 DOI: 10.1016/j.plantsci.2015.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/09/2015] [Accepted: 04/10/2015] [Indexed: 06/04/2023]
Abstract
Projected climatic impacts on crop yield and quality, and increased demands for production, require targeted research to optimise nutrition of crop plants. For wheat, post-anthesis carbon and nitrogen remobilisation from vegetative plant parts and translocation to grains directly affects grain carbon (C), nitrogen (N) and protein levels. We analysed the influence of increased atmospheric CO2 on the expression of genes involved in senescence, leaf carbohydrate and nitrogen metabolism and assimilate transport in wheat under field conditions (Australian Grains Free Air CO2 Enrichment; AGFACE) over a time course from anthesis to maturity, the key period for grain filling. Wheat grown under CO2 enrichment had lower N concentrations and a tendency towards greater C/N ratios. A general acceleration of the senescence process by elevated CO2 was not confirmed. The expression patterns of genes involved in carbohydrate metabolism, nitrate reduction and metabolite transport differed between CO2 treatments, and this CO2 effect was different between pre-senescence and during senescence. The results suggest up-regulation of N remobilisation and down-regulation of C remobilisation during senescence under elevated CO2, which is consistent with greater grain N-sink strength of developing grains.
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Affiliation(s)
- Peter Buchner
- Plant Biology and Crop Science Department, Rothamsted Research, Harpenden AL5 4TX, UK.
| | - Michael Tausz
- School of Ecosystem and Forest Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia.
| | - Rebecca Ford
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville Campus, Melbourne, VIC 3010, Australia.
| | - Audrey Leo
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville Campus, Melbourne, VIC 3010, Australia.
| | - Glenn J Fitzgerald
- Department of Economic Development, Jobs, Transport and Resources, 110 Natimuk Road, Horsham, VIC 3400, Australia.
| | - Malcolm J Hawkesford
- Plant Biology and Crop Science Department, Rothamsted Research, Harpenden AL5 4TX, UK.
| | - Sabine Tausz-Posch
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville Campus, Melbourne, VIC 3010, Australia.
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16
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Thilakarathne CL, Tausz-Posch S, Cane K, Norton RM, Fitzgerald GJ, Tausz M, Seneweera S. Intraspecific variation in leaf growth of wheat (Triticum aestivum) under Australian Grain Free Air CO 2 Enrichment (AGFACE): is it regulated through carbon and/or nitrogen supply? Funct Plant Biol 2015; 42:299-308. [PMID: 32480675 DOI: 10.1071/fp14125] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 10/13/2014] [Indexed: 05/18/2023]
Abstract
Underlying physiological mechanisms of intraspecific variation in growth response to elevated CO2 concentration [CO2] were investigated using two spring wheat (Triticum aestivum L.) cultivars: Yitpi and H45. Leaf blade elongation rate (LER), leaf carbon (C), nitrogen (N) in the expanding leaf blade (ELB, sink) and photosynthesis (A) and C and N status in the last fully expanded leaf blade (LFELB, source) were measured. Plants were grown at ambient [CO2] (~384µmolmol-1) and elevated [CO2] (~550µmolmol-1) in the Australian Grains Free Air CO2 Enrichment facility. Elevated [CO2] increased leaf area and total dry mass production, respectively, by 42 and 53% for Yitpi compared with 2 and 13% for H45. Elevated [CO2] also stimulated the LER by 36% for Yitpi compared with 5% for H45. Yitpi showed a 99% increase in A at elevated [CO2] but no A stimulation was found for H45. There was a strong correlation (r2=0.807) between LER of the ELB and soluble carbohydrate concentration in LFELB. In ELB, the highest spatial N concentration was observed in the cell division zone, where N concentrations were 67.3 and 60.6mg g-1 for Yitpi compared with 51.1 and 39.2mg g-1 for H45 at ambient and elevated [CO2]. In contrast, C concentration increased only in the cell division and cell expansion zone of the ELB of Yitpi. These findings suggest that C supply from the source (LFELB) is cultivar dependent and well correlated with LER, leaf area expansion and whole-plant growth response to elevated [CO2].
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Affiliation(s)
- Chamindathee L Thilakarathne
- Department of Agriculture and Food Systems, Melbourne School of Land and Environment, The University of Melbourne, Water Street, Creswick, Vic. 3363, Australia
| | - Sabine Tausz-Posch
- Department of Agriculture and Food Systems, Melbourne School of Land and Environment, The University of Melbourne, Water Street, Creswick, Vic. 3363, Australia
| | - Karen Cane
- Department of Environment and Primary Industries, Horsham, Vic. 3400, Australia
| | - Robert M Norton
- International Plant Nutrition Institute, Horsham, Vic. 3400, Australia
| | - Glenn J Fitzgerald
- Department of Environment and Primary Industries, Horsham, Vic. 3400, Australia
| | - Michael Tausz
- Department of Agriculture and Food Systems, Melbourne School of Land and Environment, The University of Melbourne, Water Street, Creswick, Vic. 3363, Australia
| | - Saman Seneweera
- Department of Agriculture and Food Systems, Melbourne School of Land and Environment, The University of Melbourne, Water Street, Creswick, Vic. 3363, Australia
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17
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Houshmandfar A, Fitzgerald GJ, Tausz M. Elevated CO2 decreases both transpiration flow and concentrations of Ca and Mg in the xylem sap of wheat. J Plant Physiol 2015; 174:157-60. [PMID: 25462978 DOI: 10.1016/j.jplph.2014.10.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 10/17/2014] [Accepted: 10/17/2014] [Indexed: 05/14/2023]
Abstract
The impact of elevated atmospheric [CO2] (e[CO2]) on plants often includes a decrease in their nutrient status, including Ca and Mg, but the reasons for this decline have not been clearly identified. One of the proposed hypotheses is a decrease in transpiration-driven mass flow of nutrients due to decreased stomatal conductance. We used glasshouse and Free Air CO2 Enrichment (FACE) experiments with wheat to show that, in addition to decrease in transpiration rate, e[CO2] decreased the concentrations of Ca and Mg in the xylem sap. This result suggests that uptake of nutrients is not only decreased by reduced transpiration-driven mass flow, but also by as yet unidentified mechanisms that lead to reduced concentrations in the xylem sap.
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Affiliation(s)
- Alireza Houshmandfar
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, Victoria 3363, Australia.
| | - Glenn J Fitzgerald
- Department of Environment and Primary Industries, Horsham, Victoria 3401, Australia.
| | - Michael Tausz
- Department of Forest and Ecosystem Science, The University of Melbourne, 4 Water Street, Creswick, Victoria 3363, Australia.
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18
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Fernando N, Panozzo J, Tausz M, Norton RM, Fitzgerald GJ, Myers S, Nicolas ME, Seneweera S. Intra-specific variation of wheat grain quality in response to elevated [CO2] at two sowing times under rain-fed and irrigation treatments. J Cereal Sci 2014. [DOI: 10.1016/j.jcs.2013.12.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Tausz-Posch S, Norton RM, Seneweera S, Fitzgerald GJ, Tausz M. Will intra-specific differences in transpiration efficiency in wheat be maintained in a high CO₂ world? A FACE study. Physiol Plant 2013; 148:232-45. [PMID: 23035842 DOI: 10.1111/j.1399-3054.2012.01701.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 08/21/2012] [Accepted: 09/01/2012] [Indexed: 05/03/2023]
Abstract
This study evaluates whether the target breeding trait of superior leaf level transpiration efficiency is still appropriate under increasing carbon dioxide levels of a future climate using a semi-arid cropping system as a model. Specifically, we investigated whether physiological traits governing leaf level transpiration efficiency, such as net assimilation rates (A(net)), stomatal conductance (g(s)) or stomatal sensitivity were affected differently between two Triticum aestivum L. cultivars differing in transpiration efficiency (cv. Drysdale, superior; cv. Hartog, low). Plants were grown under Free Air Carbon dioxide Enrichment (FACE, approximately 550 µmol mol⁻¹ or ambient CO₂ concentrations (approximately 390 µmol mol⁻¹). Mean A(net) (approximately 15% increase) and gs (approximately 25% decrease) were less affected by elevated [CO₂] than previously found in FACE-grown wheat (approximately 25% increase and approximately 32% decrease, respectively), potentially reflecting growth in a dry-land cropping system. In contrast to previous FACE studies, analyses of the Ball et al. model revealed an elevated [CO₂] effect on the slope of the linear regression by 12% indicating a decrease in stomatal sensitivity to the combination of [CO₂], photosynthesis rate and humidity. Differences between cultivars indicated greater transpiration efficiency for Drysdale with growth under elevated [CO₂] potentially increasing the response of this trait. This knowledge adds valuable information for crop germplasm improvement for future climates.
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Affiliation(s)
- Sabine Tausz-Posch
- Department of Agriculture and Food Systems, The University of Melbourne, Creswick, VIC 3363, Australia.
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20
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Affiliation(s)
- C Rico
- Département de biologie, Université Laval, Cite universitaire Quebec, Canada
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21
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Abstract
All patients with primary cardiac disease presenting with out-of-hospital sudden cardiac death (OH-SCD) to a provincial hospital were reviewed retrospectively over a 5-year period from 1985 to 1989. This coincided with the introduction of out-of-hospital defibrillation (OH-DEFIB) by ambulance officers. Of 215 patients, 17 (9%) survived to leave hospital alive, 15 of whom underwent OH-DEFIB. There was an increase in survivors from 4%, prior to OH-DEFIB, to 9% of all cardiac arrests, but this was not statistically significant (P = 0.3). However, long term survival amongst immediate survivors was associated with a statistically significant improvement following the introduction of OH-DEFIB (15 of 30 (50%) vs. 2 of 19 (10.5%), P < 0.01). Mean call-out, at-scene and transfer times did not significantly vary between survivors and non-survivors. A total of 155 (72%) had a known cardiac history, with the majority (74%) of arrests occurring at home. Of 134 witnessed arrests, only 46 (34%) underwent bystander-initiated cardiopulmonary resuscitation (CPR). A programme in CPR aimed at relatives of known cardiac patients, and the adoption of a paramedic protocol which improves oxygenation at the time of arrest are recommended.
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Affiliation(s)
- I A Scott
- Ipswich General Hospital, Queensland, Australia
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22
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Abstract
The perceived urgency of 2000 consecutive patients attending the Accident and Emergency Department of the Royal Infirmary, Edinburgh, was assessed using a Linear Analogue Scale. Each patient was assessed by the receptionist, the receiving nurse and the treating doctor. The distribution of urgency rating produced for this patient group was shown to be comparable for each status of assessor, and to correlate with other outcome criteria such as admission and referral rates. The linear scale was also shown to correlate with retrospective assessment using a time-guided category scale. The accident and emergency department workload is predominantly of low urgency (90% less than 5 on a 0-10 scale). Older patients tend to have higher urgency ratings than younger patients and those referred by ambulance, either via general practitioner or 999 calls, have similarly higher urgency distributions. This study provides a basis for the development of a guided category scale for functional triage of accident and emergency departments. Other scoring systems have attempted to similarly quantify the medical component of the workload (Coira & Rothstein, 1983; Peel et al., 1962). However, the complexity of many of these scales, together with the difficulty in usage of so many different scales, begs a reappraisal of the overall triage of patients attending the emergency department. The aim of this study was to look at the perceived urgency distribution of patients presenting to the emergency department. We wished to compare the relative assessment of urgency by various levels of treating staff and to compare those assessments with the referral and outcome of these patients to provide the basis for the development of a comparative Triage Scale.
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