Long-Term Exposure To Global Changes In Grassland Ecosystems: Whole-Season And Temporal Trends In Changing Productivity In Response To Increased Carbon Dioxide Level And Air Temperature,
2024
Universiteit Antwerpen
Long-Term Exposure To Global Changes In Grassland Ecosystems: Whole-Season And Temporal Trends In Changing Productivity In Response To Increased Carbon Dioxide Level And Air Temperature, I Nijs, H Teughels, I Impens, T Behaeghe
IGC Proceedings (1977-2023)
Six commercial grass cultivars were exposed to elevated CO2 level (±700 ppm), increased air temperature (+4°C) or a combination of both during an entire growing season, using a "field tracking system" for continuous simulation of outside field temperatures (or ambient 44C), inside sunlit greenhouse units. On a whole-season basis, elevated CO2 positively affected above-ground productivity, with a range of 11-30%, depending on species, although early-season stimulation was smaller than late spring CO2 gain. Effects of increased temperature were positive in spring, but decreased towards summer and became negative for almost all species, yielding a "no effect" seasonal balance. Almost no …
Effect Of Elevated Carbon Dioxide On The Performance Of Nine Coexisting Grassland Species,
2024
University of York
Effect Of Elevated Carbon Dioxide On The Performance Of Nine Coexisting Grassland Species, J Watson, J D. Graves
IGC Proceedings (1977-2023)
Microcosms were constructed to represent a neutral grassland community under traditional agricultural management. During a season of fumigation at ambient and 600 µmot/mot CO2, plant performance was recorded. An increase of biomass for the whole community resulted at elevated CO2, but the response of individual species differed, There are indications that competitive interactions may change within a community due to the effects of CO2 enrichment; this may eventually result in a change in species composition.
Effects Of Different Grass Species On Nitrogen Fixation By White Clover Under Conditions Of Elevated Carbon Dioxide And Temperature,
2024
AgResearch, NZ
Effects Of Different Grass Species On Nitrogen Fixation By White Clover Under Conditions Of Elevated Carbon Dioxide And Temperature, J R. Crush, B D. Campbell
IGC Proceedings (1977-2023)
Growing clover in binary mixtures reduced clover shoot dry matter (DM) and nitrogenase activity compared with clover in monoculture. Nitrogenase activity/g clover shoot OM increased in the mixtures to a similar extent with 5 different companion grass species. Elevated atmospheric 002 increased nitrogenase activity/g clover OM in the mixtures but specific nitrogenase activity was not changed with increased temperature. Using nitrogenase activity/unit grass OM as a competitive index showed that elevated CO2 reduced competitive stress on white clover. Two tropical grasses (Pennisetum clandestinum and Paspalum dilatatum) were less competitive to white clover at 18/13°C than 3 temperate species …
Effect Of Elevated Atmospheric Carbon Dioxide Levels On Nodule Relative Efficiency In White Clover,
2024
AgResearch, NZ
Effect Of Elevated Atmospheric Carbon Dioxide Levels On Nodule Relative Efficiency In White Clover, J R. Crush, B D. Campbell, J.P M. Evans
IGC Proceedings (1977-2023)
Plant growth, total nitrogenase activity and hydrogen evolution rates were determined for 39-, 47- and 54-day-old white clover (Trifo/ium repe11s L.) plants growing at 350 or 700 ppm CO2 with day/night temperatures of 18/13°C or 28/23°C. The three plant parameters increased with plant age, temperature and CO2 concentration. Nitrogenase activity/g plant dry matter (DM) and hydrogen evolved/ g DM decreased as plants developed, presumably as nitrogen was cycled internally and plants became less reliant on recently fixed nitrogen. Nodule relative efficiency - an expression of the energy flux to nitrogenase relative to hydrogen production - was significantly lower initially in …
Climate, Land Use And Plant Life Form Distribution In A Semi-Arid Savanna,
2024
Uppsala Universitet
Climate, Land Use And Plant Life Form Distribution In A Semi-Arid Savanna, Christina Skarpe
IGC Proceedings (1977-2023)
Number of plant species, total vegetation cover and the abundance of different life forms are compared over a rainfall gradient between savanna woodland and semi-desert. The effects of different land use intensities are superimposed on the differences in rainfall regimes. The outcome is discussed in the light of present global change scenarios,
Vegetation Response To Climate: A 35 Year Study At Bibury, Gloucestershire,
2024
The University of Sheffield
Vegetation Response To Climate: A 35 Year Study At Bibury, Gloucestershire, A J. Willis, R Hunt, J P. Grime, S R. Band, N Dunnett
IGC Proceedings (1977-2023)
Important information on the climate-responsiveness of plant species has been gleaned from an unlikely source. The annually recorded control {unsprayed) plots from a 35-year field e, experiment assessing the effects of spraying herbicide and a plant growth regulator onto the vegetation of roadside verges near Bibury, Gloucestershire, have provided an opportunity to examine the detailed effects of year-to year variations in climate on the yields of different ·species and functional types within the vegetation. The results confirm the usefulness of plant functional types and genome size as predictors of plant community response to climatic change.
Response Of White Clover To Soil Phosphate Levels At Different Temperatures And Carbon Dioxide Concentrations,
2024
AgResearch, NZ
Response Of White Clover To Soil Phosphate Levels At Different Temperatures And Carbon Dioxide Concentrations, R A. Carran
IGC Proceedings (1977-2023)
Nutrient availability is generally managed to remove limitations when the effects of elevated temperature or CO2 concentrations on plants are investigated. Relating the resulls of such experiments to field situations where nutrients are frequently in short supply is difficult. Phosphorous response curves were obtained for white clover (Trifolium repens L,) seedlings grown at temperatures of 18-13 or 28-23°C, nod 350 or 700 ppm CO2. At low P, response to other variables was non-significant and at 18-13° there was no response to increased CO2, Increasing temperature to 28-23° resulted in increased gcowth, apparently due to increased P availability, and at …
The Integrated Screening Programme: Patterns Of Ecological Specialization In British Species,
2024
University of Sheffield
The Integrated Screening Programme: Patterns Of Ecological Specialization In British Species, K Thompson, J P. Grime, R Colasanti
IGC Proceedings (1977-2023)
The Integrated Screening Programme (ISP), a major part of the UCPB research programme during the period 1987-1994, applies standardised procedures for the ecological, physiological and biochemical characterisation of plant species, populations or cultivars. The objectives are: (1) to establish the range of variation in selected plant attributes; (2) to recognise recurring patterns of ecological and evolutionary specialisation; (3) to devise a functional classification of plants relevant to the analysis of communities and ecosystems and the management of vegetation .. To date, the programme has been confined largely to the herbaceous species from central northern Britain. Later, and in particular as …
Interaction Of Climate Management As Controls On Species Composition,
2024
University of Sheffield
Interaction Of Climate Management As Controls On Species Composition, S H. Hillier, F Sutton, J P. Grime, R Colasanti
IGC Proceedings (1977-2023)
A new technique for the manipulation of temperature near the soil surface without the aid of cloches or screens has been developed at UCPE. This system is being used to manipulate the length of the growing season in an experiment in which the critical interaction between growth and the timing of two important meadow management activities - cutting and grazing - is being investigated. The technique has also been used to expose synthesised meadow communities to an artificially induced mild winter. Temperature manipulations of this kind offer a new approach to understanding the role which climate plays as a mechanism …
Comparison Of Photosynthetic Responses To Carbon Dioxide In Pasture Species,
2024
HortResearch, NZ
Comparison Of Photosynthetic Responses To Carbon Dioxide In Pasture Species, D H. Greer, W A. Laing, B D. Campbell
IGC Proceedings (1977-2023)
Thirteen major pasture species were grown in controlled environments at 3 temperatures (12n, 18/13 and 28/23°C) and at 350 nnd 700 ppm CO2 for 4-8 weeks and net photosynthesis measured under these conditions. In C1 cultivars, short-term (within minutes) exposure to elevated CO2 had the greatest effect on photosynthesis, with an average of 55% higher rates than that at ambient CO2. There was also a response to long-term growth at high CO2, with a,1 average of 40% higher rates of photosynthesis than at ambient CO2 (both measured al their growth CO2) and a marked alteration in the temperature dependence Qf …
Photosynthesis And Water Relations Of A C4 And A C3 Grass Under Doubled Carbon Dioxide,
2024
Kansas State University
Photosynthesis And Water Relations Of A C4 And A C3 Grass Under Doubled Carbon Dioxide, D Nie, M B. Kirkham, E T. Kanemasu
IGC Proceedings (1977-2023)
The objective of this project was to determine during an entire season the photosynthetic rate and water potential of a C3 grass (Kentucky bluegrass, Poa pratensis L.) and a C4 grass (big bluestem, Andropogon gerardii Vitman) grown with 2 levels of CO2 (ambient or twice ambient) and 2 water levels (field capacity or no water added). Elevated CO2 increased the photosynthetic rate of Kentucky bluegrass by an average of 76%. During mid-season (11 June-16 July), photosynthetic rate of high-water big bluestem with ambient CO2 was about the same as that of low-water big bluestem with doubled CO2• Under both water …
Simulating The Impact Of Global Warming On Regional Pasture Production Environment,
2024
CSIRO
Simulating The Impact Of Global Warming On Regional Pasture Production Environment, P J. Vickery, M J. Hill, E P. Furnival
IGC Proceedings (1977-2023)
Global warming scenarios predict increases in temperatures, evaporation and summer rainfall in the northern two-thirds of Australia. Pasture production models can be combined with spatial climate data in a geographic information system to predict net primary production from pastures. We used a pasture-sheep production model for a phalaris-white clover pasture together with interpolated climatic data to predict the outcome of increases in temperature, evaporation and summer rainfall for net primary production (NPP) from pastures in northern NSW. NPP was predicted to rise in winter due to elevated temperatures, to decline slightly In spring due to increased evaporation, and to change …
Changing The Climate Of A Limestone Dale,
2024
University of Sheffield
Changing The Climate Of A Limestone Dale, S M. Buckland, J P. Grime, J R. Tippets, A Jackson, K Thompson, J G. Hodgson, P C. Thorpe, C W. Macgillivray
IGC Proceedings (1977-2023)
The Unit of Comparative Plant Ecology based at Sheffield University is manipulating the weather artificially at a field site near Buxton, Derbyshire. This experiment is enabling us to study the way in which certain plants, both in the existing vegetation and among potential invaders, may behave in the future. As well as future climate scenarios, a range of land-use conditions are recreated in the experiment. Seeds of species with different geographical distributions have been sown in and their fate is being closely followed. The experiment began in 1990 and will run until at least 1997, by which time it should …
Improving Pasture Digestibility: Low Lignin Forages,
2024
CSIRO
Improving Pasture Digestibility: Low Lignin Forages, C Lynne Mcintyre, Sharon L. Abrahams, Heather M. Bettenay, Ruth A. Sandeman, Christine Hayes, Donovan Sharp, Adrian Elliot, John M. Manners, John M. Watson
IGC Proceedings (1977-2023)
High lignin content in forages reduces dry matter digestibility and voluntary feed intake by ruminants. Ribozyme and antisense RNA technologies are being investigated as methods of reducing lignin levels and increasing digestibility in temperate and tropical forages. Pirstly, potential target genes in the lignin biosynthetic pathway, against which ribozyme and antisense contructs may be targeted, are being isolated from the temperate and tropical legumes, lucerne and Sty/osa11thes lmmilis, respectively. Secondly, promoter sequences that may direct expression of ribozyme and antisense contructs to specific cells and tissues are being isolated, Thirdly, various ribozyme design and delivery systems are being investigated in …
Transfer Of Genes Encoding Proteins With High Nutritional Value Into Pasture Legumes,
2024
CSIRO
Transfer Of Genes Encoding Proteins With High Nutritional Value Into Pasture Legumes, W C. Mcnabb, C Higgins, L Tabe, T J.V Higgins
IGC Proceedings (1977-2023)
Gene transfer systems for the forage legumes, subterranean clover (Trlfolium subterraneum) and lucerne (Medicago saltva) have been developed and optimised for current commercial cultivars. A disarmed binary vector derived from the Agrobacterium tunefaciens tumour• inducing plasmid has been used to deliver a selectable marker gene conferring resistance to phosphinothricin (the active ingredient in the herbicide, Basta) and a series of chimeric gene constructs encoding proteins that are rich in sulphur amino acids and resistant to rumen degradation. Transgenic plants expressing a gene encoding either ovalbumin or a sunflower albumin have been obtained and analyzed with respect to …
Developing A Tall Fescue For Reduced Grass Tetany Risk,
2024
USDA, Agricultural Research Service
Developing A Tall Fescue For Reduced Grass Tetany Risk, H F. Mayland, D A. Sleper
IGC Proceedings (1977-2023)
Tall fescue (Festuca arundinacea Schreb,) is an important forage grass, and like other C3 grasses, has the potential to cause grass tetany in grazing ruminants. Genetic variation in cation uptake by fescue was exploited by selecting for high Mg and Ca relative to K CQncenlration in fescue, The grass tetany ratio, K/(Ca+Mg), was reduced about 18% after 2 selection cycles. The mean Mg and K/(Ca+Mg) values for 20 C1 plants, grown at pH 6.4, were weakly related (r2-0.42 and 0.48) to those of plants grown in calcareous soil pH 8.2. The P, Na, Mn, Fe, Cu, and Zn concentrations …
Volatile Constituents Of Tall Fescue Varieties In Relation To Palatability,
2024
Instituto Sperimentale Colture Foraggere
Volatile Constituents Of Tall Fescue Varieties In Relation To Palatability, Aldo Tava, Nicola Berardo, Miriam Odoardi
IGC Proceedings (1977-2023)
The chemical composition of the essential oil of tall fescue (Festuca arundinacea Schreb,), a poorly palatable species, was analysed by GC and GC-MS. The major components identified were alcohols, aldehydes and esters. The qualitative and quantitative differences detected among 6 cultivars of different geographical origin suggest the most abundant compounds may play a role in the grazing preference exhibited by animals.
Cell Wall Phenolic Content In Tissue Types Of Developing Maize Internodes,
2024
USDA, Agricultural Research Service
Cell Wall Phenolic Content In Tissue Types Of Developing Maize Internodes, T A. Morrison, D R. Buxton
IGC Proceedings (1977-2023)
Elongation and lignification was observed via daily photographs and phloroglucinol-HCI stain on internode 9 (1-9) of growth-chamber grown maize (Zea mays L.) line Mol7 x B73 to correlate internode development with lignification. 1-9 elongated sigmoidally from 8 to 130 mm in 12 days. Lignification began in the upper internode after 3 d and progressed top-down following a basipetal retreat of elongation activity. An improved acetyl bromide method was used to determine UV-absorptive cell wall phenolic concentrations in freeze. dried, ethanol and chloroform:methanol extracted pith parenchyma, pith vascular and rind vascular tissue excised from lower and upper sections of immature, lignifying, …
Partitioning Of Major Elements Concentrations In Grasses Into Four Cell Fractions Based On Enzymatic Solubility,
2024
Iwate University
Partitioning Of Major Elements Concentrations In Grasses Into Four Cell Fractions Based On Enzymatic Solubility, Suguru Saiga, Takanori Akiyama, Moegi Saski, Kiyoshi Watanabe
IGC Proceedings (1977-2023)
To investigate availability of major elements to animals, N, P, K, Ca and Mg of plant dry matter were partitioned into 4 cell fractions based on enzyme solubility. When the elemental concentration of forage was compared, Dactylis glomerata was higher in K (1.69%), Festuca aru11dinacea in N (2.35%), K (1.68%) and Mg (Q.341 %) and Lolimum perenne in N (2.54%), P (0.224%) and Ca (0.457%). When compared between plant parts, concentrations of all elements.were higher in leaf than in stem, especially P, Ca and Mg. As a result of partitioning, more than 85% of P, K and Mg resided …
Improvement Of The Feeding Value Of Senescent Grass Pastures By Molecular Genetic Manipulation,
2024
The University of Melbourne
Improvement Of The Feeding Value Of Senescent Grass Pastures By Molecular Genetic Manipulation, G D. Bonnett, K R. Stevenson, R J. Simpson
IGC Proceedings (1977-2023)
Senescent grass pasture has low feeding value end is the major limitation to animal productivity during summer in annual environments. The loss of fructan from the stems of temperate grasses as they senesce contributes significantly to the decline in feeding value of the grass, Temporary retention of fructan during senescence achieved by treating grass with a herbicide increases both the feeding value of the grass and the productivity of animals grazing the modified pasture. We have identified an enzyme responsible for initiating the loss of fructan from stems of Lolium rigidum. It has been purified, characterized and will be used …
