Coat Protein-Mediated Protection Against White Clover Mosaic Virus And Potato Virus X In Tobacco,
2024
Horticulture and Food Research Institute of NZ
Coat Protein-Mediated Protection Against White Clover Mosaic Virus And Potato Virus X In Tobacco, D L. Beck, C J. Van Dolleweerd, B Dudas, D R.W White, R.L S. Forster
IGC Proceedings (1977-2023)
The coat protein genes of the potexviruses white clover mosaic virus (WClMY) or potato virus X (PVX) were introduced into Nicotiana benthamiana plants by gene transfer. Transgenic plants expressing the coal protein gene of WCIMY or PYX were highly resistant to infection when challenge-inoculated with the virus from which the coat protein gene was obtained (homologous challenge). Similar resistance was obtained when homologous viral RNA was used as inoculum, The transgenic plants were also protected against infection with the heterologous virus, but only at low inoculum concentrations. The level of protection in PYX transgenic plants was directly correlated with the …
Transformation Of White Clover With A Gene Encoding A Lepidopteran-Active- Endotoxin From Bacillus Thuringiensis Var. Berliner 1715,
2024
AgResearch, NZ
Transformation Of White Clover With A Gene Encoding A Lepidopteran-Active- Endotoxin From Bacillus Thuringiensis Var. Berliner 1715, C R. Voisey, D.W R. White, P G. Mcgregor, B L. Barker
IGC Proceedings (1977-2023)
During sporulation, Bacillus thuringiensis var. berliner 1715 produces insecticidal proteins (6-endotoxins) that are lethal specifically to Lepidopternn insects. Agrobacterium tumefaciens-mediated T-DNA transfer has been used to introduce a cry/A(b) li-endotoxin gene (the 812 gene) from this B. thuringiensis strain into a genotype of white clover (WR8). The aim is to protect white clover (Trifolium repens L.) from damage caused by Lepidopteran insects, including the pasture pests porina (Wiseana spp.) and sod-web worms (Crombidae), White clover plants were transformed with a binary vector (pGSH 163) containing the bidirectional mannopine synthase promoter which directs simultaneous expression of both …
Prediction Of Grassland Plant Responses To Global Change,
2024
AgResearch, NZ
Prediction Of Grassland Plant Responses To Global Change, B D. Campbell, J P. Grime
IGC Proceedings (1977-2023)
Global change is challenging the predictive power of biology. Increasingly, biologists are being asked to draw together existing knowledge and new experimental data, in order to provide predictions of the effects of global change at regional, national and global scales. In this paper we examine how well global change effects on grassland plants can be predicted, and what avenues might be used in future to improve predictive capabilities. Broad predictions of the direction of change in grassland vegetation can be made quite simply and from a limited set of data. Predictions of the rate and magnitude of change are more …
Climate Change And Grasslands: Ecosystem-Level Responses To Elevated Carbon Dioxide,
2024
Kansas State University
Climate Change And Grasslands: Ecosystem-Level Responses To Elevated Carbon Dioxide, Clenton E. Owensby
IGC Proceedings (1977-2023)
Elevated CO2 is the major greenhouse gas associated with global climate change. The impact of increasing atmospheric CO2 on grassland ecosystems has been studied little. Studies with single plants or populations in controlled environments have provided knowledge of the mechanisms involved in plant response to elevated CO21 but without ecosystem-level studies over an extended period, we will be unable to make any valid predictions. Primary production of grassland ecosystems under elevated CO2 will likely increase, with the greatest increase coming with C3-dominated plant communities, or plant communities that are .subjected to frequent drought stress. Increased nitrogen-use efficiency and reduced nitrogen …
Variation In The Response Of Pasture Plants To Carbon Dioxide,
2024
AgResearch, NZ
Variation In The Response Of Pasture Plants To Carbon Dioxide, B D. Campbell, W A. Laing, P.C D. Newton
IGC Proceedings (1977-2023)
The percentage increases in growth resulting from a doubling of atmospheric CO2 concentration were measured for 37 common pasture plants under strictly controlled conditions of temperature, nutrient supply and irradiance. A wide range of variation in potential response lo CO2 was detected in the day/night temperature range 12n°c to 28/ 23°C. C4 species responded litlle to elevated CO2 The mean ± standard deviation of the distribution of c3 species responses ranged from l±21% at 1m•c to 90±40% at 28/23°C. These responses varied with the stage of plant development. The response by Lolium perenne cv. Grasslands Nui was of intermediate size …
Will Subtropical Grasses Keep Spreading Through New Zealand?,
2024
AgResearch, NZ
Will Subtropical Grasses Keep Spreading Through New Zealand?, B D. Campbell, R.J M. Hay
IGC Proceedings (1977-2023)
n this paper we briefly examine the effects that rising temperature and atmospheric CO2 concentrations may have on the spread of subtropical grasses in New Zealand. Data are presented from controlled-environment experiments measuring the growth and competitive suppression of white clover by a variety of local temperate and subtropical grasses at CO2 concentrations of 3S0 ppm and 700 ppm. These data support the prediction that some subtropical grasses may decline in aggressiveness relative to temperate species in New Zealand in the future as atmospheric CO2 levels rise. Some of the factors likely to modify the expression of temperature and CO2 …
Effect Of Carbon Dioxide Concentration On The Competitive Ability Of Clover: Measurements Of Growth And Rubisco,
2024
HortResearch, NZ
Effect Of Carbon Dioxide Concentration On The Competitive Ability Of Clover: Measurements Of Growth And Rubisco, W A. Laing, D H. Greer, B D. Campbell
IGC Proceedings (1977-2023)
White clover (Trifolium repens cv. Grasslands Huia) was grown in competition with one of 10 established grass species or else grown alone. Plants were grown at either 350 or 700 ppm CO2, at 28/23°C and 700 µmol/m1/sec photon flux density. Plant growth and extractable ribulose bisphosphate carboxylase (rubisCO) were measured. Grass growth responded less to CO2 than clover. In the absence of grass competition, clover growth Increased 30% under 700 ppm CO2 compared with 350 ppm, but the response varied from 0% to 100% • when grass competition was present. Increased CO2 reduced extractable rubisCO activity (expressed on a …
Response Of Natural Turves Of Pasture To Elevated Carbon Dioxide In A Controlled Environment,
2024
AgResearch, NZ
Response Of Natural Turves Of Pasture To Elevated Carbon Dioxide In A Controlled Environment, P.C D. Newton, H Clark, C C. Bell, E M. Glasgow
IGC Proceedings (1977-2023)
Large natural turves from a ryegrass-white clover (Lolium pernne, trifolium repens) pasture were exposed to increasing day/nighl temperatures at 350 and 700 µVI CO2 over a 7•month period. Growth rate al the highest temperature (22/16°C day/night) was IS% higher at the elevated CO2 level; at lower temperatures the response to CO2 was reduced or even negative (-6% at 10/4°C). The growth rate of ryegrass was much lower at elevated CO2 while that of white clover and other grasses was increased. These results are compared with previous studies using synthetic communities, and the limited response to CO2 is noted …
Implications Of A Doubling In Ambient Carbon Dioxide Levels Of Herbage Quality In Perennial Ryegrass And White Clover,
2024
AgResearch, NZ
Implications Of A Doubling In Ambient Carbon Dioxide Levels Of Herbage Quality In Perennial Ryegrass And White Clover, H Clark, C C. Bell, P.C D. Newton, B D. Campbell
IGC Proceedings (1977-2023)
Digestibility (DMD) and crude protein (CP) percentage in leaf and stem of 4 cultivars each of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) grown at 3 day/night temperatures (12f7, 18/ 13, 28/23°C) and 2 CO2 concentrations (35 0 or 700 ppm) was estimated using near infrared reflectance spectroscopy (N[RS). Differences between cultivars in DMD and CP were small and non-significant. Higher temperatures reduced DMD andCP in both species. DMD was unaffected by CO2 concentration in either species. The higher concentration of CO2 reduced leaf and stem CP by 14.6 and 10% respectively in white clover …
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 …
