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 …
Genetic Engineering Of Pasture Legume And Grasses For Reduced Lignin Content And Increased Digestibility,
2024
CSIRO
Genetic Engineering Of Pasture Legume And Grasses For Reduced Lignin Content And Increased Digestibility, C Lynne Mcintyre, J M. Manners, J R. Wilson, H Way, D Sharp
IGC Proceedings (1977-2023)
Plants of tropical pastures have a higher lignin content than those of temperate pastures, which limits the digestibility and nutritive value of these forages. Ribozyme and antisense RNA technology is being investigated as a method of reducing lignin levels and increasing digestibility in the tropical forage Stylosanthes spp, and in the model system tobacco. Ribozymes to the tobacco anionic peroxidase mRNA have been designed and shown to be capable of cleaving this mRNA in vitro. Constructs for the expression of antisense and ribozyme RNA to reduce peroxidase gene expression have been prepared, Transgenic tobacco plants containing these constructs have been …
Sulphur-Rich Protein Gene Modification For Optimized Expression In Transgenic White Clover,
2024
AgResearch, NZ
Sulphur-Rich Protein Gene Modification For Optimized Expression In Transgenic White Clover, Paul M. Ealing, K Hancock, D.W R. White, T/J V. Higgins
IGC Proceedings (1977-2023)
A gene encoding the sulphur-rich pea seed storage protein pea albumin I (PAI), transcriptionally fused to the CaMV 35S promoter has been introduced into Nicotiana Iabacum and white clover (Trifolium repens L.) using Agrobacterium-mediated transformation. PA I mRNA expression has been confirmed in transgenic tobacco and white clover plants. However, PAI protein accumulation, as assessed by ELISA using an anti-PAI monoclonal antibody, is either low or the antibody does not have the required avidity or titre. Strategies for improved accumulation and immunological surveillance of this protein in leaf tissue are described, including the construction of PA …
Modeling The Effects Of Climate Variability And Climate Change On A Pastoral Farming System,
2024
New Zealand Institute for Crop and Food Research
Modeling The Effects Of Climate Variability And Climate Change On A Pastoral Farming System, R J. Martin, D B. Baird, M J. Salinger, P R. Van Gardingen, D G. Mccall
IGC Proceedings (1977-2023)
A simulation model was used to investigate the pasture and animal production and gross margins of a typical all sheep permanent pasture farm in South Canterbury, New Zealand, using 60 years of current climate data, and also a climate change scenario. The model was run on a fixed management system at different stocking rates with and without destocking during feed shortages. Mean annual pasture production was 8060 kg/ha, with a coefficient of variation of 22%. Destocking enabled more stock to be carried on average, with higher, but rh.ore variable, returns. A climate change scenario of a 75% increase in CO2' …
Changes To Sheep Grazing Systems In Response To Climate Change,
2024
Massey University
Changes To Sheep Grazing Systems In Response To Climate Change, B M. Butler, S T. Morris, R S. Morris
IGC Proceedings (1977-2023)
Simulation models were used to predict changes in pasture growth and sheep farming systems as a result of changes in climate due to global warming. The results of long•lerm mean climate and 10 years' individual climate simulations show Iha! increases in stocking rate of up to 40% may be possible with climate change. Benefits of climate change included increased lamb carcass weight and pasture cover. Climate change also resulted in the feasibility of autumn lambing systems in an environment in which these systems are currently difficult lo maintain. A change from 100% spring lambing to 40% of the flock lambing …
Influence Of The Photochemical Air Pollutant, Ozone, On Grass-Clover Plots Using An Open Air Fumigation System,
2024
University of Newcastle-upon-Tyne
Influence Of The Photochemical Air Pollutant, Ozone, On Grass-Clover Plots Using An Open Air Fumigation System, S Wilbourn, A Davison, J Ollerenshaw
IGC Proceedings (1977-2023)
Fumigation of perennial ryegrass-white clover (Lolirim perenne - Trifolium repens) plots with moderate ozone (03) concentrations caused a decline in the clover content and a reduction in total seasonal yield of the swards. There was no significant interaction between defoliation treatment and 03 fumigation. The ryegrass population benefited from the reduction in competition from the clover in 03-treated plots. These results, obtained from an open air field fumigation system confirm the findings of other experiments which used different grass-legume mixtures grown in open-top chambers or in controlled environments. Fumigation with 03 in summer caused a significant reduction in …
Climate Change And Grasslands: A Life-Zone And Biota Perspective,
2024
Texas A&M University
Climate Change And Grasslands: A Life-Zone And Biota Perspective, Steven Archer
IGC Proceedings (1977-2023)
Grasslands experiencing climatic and atmospheric change may be altered with respect to: (1) geographic extent and location of local/ regional boundaries; (2) productivity, organic matter dynamics and nutrient cycling; and (3) the relative abundance of constituent life forms (woody v. herbaceous), growth forms (tall vs. shorl-statured grasses), and/or photosynthetic physiologies (C3 v. C4). Classification models based on vegetation-climate correlations predict an increase in the global acreage of grassland and savanna at the expense of boceal forest and dry tropical forest. However, extrapolation of these relationships to climates with atmospheric CO2 concentrations without present-day analogues is suspect. Dynamic models of plant …
Climate Change And Variability: Impacts On New Zealand Pastures,
2024
NIWAR
Climate Change And Variability: Impacts On New Zealand Pastures, M J. Salinger, A S. Porteous
IGC Proceedings (1977-2023)
Climate change and variability influence the productivity and distribution of New Zealand pasture species. Temperature and rainfall scenarios are used to explore the sensitivity of New Zealand pastures to potential climate warming next century. Temperature affects the length of the growing season with present pasture species extending 200 m higher in altitude for every 1 •c temperature increase. The greater area of New Zealand that becomes frost free allows the spread of subtropical pasture grasses southwards. However, where low rainfall limits pasture production, changes to the rainfall amount have a significant effect. A rainfall change of I 0% changes the …
A Climate Change Perspective On Grasslands,
2024
CSIRO
A Climate Change Perspective On Grasslands, A Barrie Pottock
IGC Proceedings (1977-2023)
Grasslands are the result of interactions between climate, soil, interspecies competition and natural or humnn distucbance. They are vital to human sustenance but vulnerable to human mismanagement and climatic stress.• Thece is now a strong scientific consensus that climate will change during the next century at a rate unprecedented since the end of the last glaciation. Expected climatic changes include not only increasing temperatures, but also changes in total rainfall and its seasonality, and systematic increases in rainfall intensity. Along with the direct effects of increasing carbon dioxide concentrations on plants, and changes in fire frequency, these environmental influences will …
Structure Of White Clover Populations And Plants In Pastures Grazed By Beef Cattle,
2024
AgResearch, NZ
Structure Of White Clover Populations And Plants In Pastures Grazed By Beef Cattle, I Pinxterhuis, D F. Chapman, M.J M. Hay
IGC Proceedings (1977-2023)
Seasonal variation in the structure of white clover (Trifolium repens) populations and the morphology of individual plants was studied in permanent pastures grazed by beef bulls. Three grazing regimes were applied: set stocking with 5.0 bulls/ha and rotational grazing with either, 5.0 or 7 .5 bulls/ha, Management had little effect on the structure of the plants or the stolon branching structure of the population. On average, 45% of the plants were of 2nd order; this value remained relatively constant throughout the year. The proportion of 1st-order plants increased ��nd the proportion of plants of 3rd- and highCl' order …
Effects Of Defoliation Height And Time Of Initital Defoliation On Regrowth Components In A Poa Pratensis- Dominated Sward,
2024
Swedish University of Agricultural Sciences
Effects Of Defoliation Height And Time Of Initital Defoliation On Regrowth Components In A Poa Pratensis- Dominated Sward, B E. Frankow-Lindberg
IGC Proceedings (1977-2023)
Two experiments on swards dominated by Poa pratensis L. were conducted in 2 climatically contrasting (wann/dry and cold/wet) years. There were either 4 or 3 initial defoliation dates in spring and 3 defoliation heights (2, 6 and 10 cm). Regrowths were harvested 4 weeks after the initial defoliation. The swards received a total of 80 kg/ha nitrogen split into 2 dressings. Regrowth characteristics, based on samples cut to ground level, depended on weather conditions. The yield of vegetative shoots was affected most by shoot size, which in turn was determined by initial defoliation date, in the dry year. In the …
Comparative Growth Of Arrowleaf, Crimson, Rose And Subterranean Clovers In East Texas,
2024
Texas Agricultural Experiment Station
Comparative Growth Of Arrowleaf, Crimson, Rose And Subterranean Clovers In East Texas, G W. Evers
IGC Proceedings (1977-2023)
Annual clovers (Trlfolium sp.) differ in maturity and plant growth during the growing season. Undefoliated plots of Yuchi arrowleaf (T. vesiculosum Savi,), Tibbee crimson (T. incarnatum L.), Overton R18 rose (T. hurtim All.), and Mt. Barker subterranean (T. subterneum L.) clovers were sampled biweekly throughout the growing season in east Texas to study shoot and root weight. Species ranking for shoot weight during the first 100 days was crimson > subterranean > arrowleaf > rose. Ranking for root weight was the same except crimson and subterranean clovers had similar root weights for the first 49 days. Shoot weight increased rapidly in spring in …
Tiller Dynamics Of Perennation In Three Herbage Grasses,
2024
Massey University
Tiller Dynamics Of Perennation In Three Herbage Grasses, C Matthew, C K. Black, B M. Butler
IGC Proceedings (1977-2023)
Data on tiller demography of perennation in prairie grass (Bromus wildenowii Kunth), perennial ryegrass (Lolium perenne L.), and tall fescue (Festuca anmdinacea Schreb,) are presented. Two pathways of perennation are described: a reproductive pathway in which perennation is by production of daughter tillers from flowering tillers, and a vegetative pathway in which perennation is by tillering from surviving non• flowering tillers. Both pathways normally contribute to perennation. However, there are few quantitative reports in the literature on how the balance between the 2 pathways varies in different species, or under different defoliation managements, The ranking of species for dominance ri …
Effect Of Air Temperature On Plant Reserves And Regrowth Potential In Napiergrass (Pennisteum Purpurem),
2024
Taiwan Livestock Research Institute
Effect Of Air Temperature On Plant Reserves And Regrowth Potential In Napiergrass (Pennisteum Purpurem), Yeong Chyn Wang, Main Lian Lee
IGC Proceedings (1977-2023)
The response of plant reserves to air temperature and the relationship between these reserves and the regrowth potential of napiergrass (Penniseetum purpurem) after defoliation was examined. Two cultivars, A7007 and Taishiuh No. 1, were cut in Wagner pots and established outside. The plants were moved into the growth chamber for 3 weeks of temperature treatment, from 2 weeks before to 1 week after harvest. Pour temperature combinations were examined: 15-15°C (temperature before-after the harvest), 15-35 °C, 35-15°C and 35-35°C. High temperature (35°C) before the harvest benefited plant growth but was associated with lower plant reserves. The stubble stored more reserves …
Persistence Of Phalaris Aquatica L. In Response To Grazing,
2024
CSIRO
Persistence Of Phalaris Aquatica L. In Response To Grazing, R A. Culvenor
IGC Proceedings (1977-2023)
Cultivars of phalaris (Plialaris aquatica L.) bred in Australia for seedling vigour and winter activity are reported to be less persistent in response to heavy_ grazing than the original introduction, cv. Australian. In an experiment comparing the morphological characters of cultivars, Australian was shown to possess a morphology well adapted to grazing. In contrast, the bred cultivars formed more erect pastures with low basal area, more prone to invasion by annual grasses and retaining less leaf area after grazing. In a second experiment, sheep displayed preference during July for grazing the winter-active cultivar Sirosa over cv. Australian, probably because …
Effect Of Management On Leaf Growth And Senescence Of Three Contrasting Grass Species,
2024
Massey University
Effect Of Management On Leaf Growth And Senescence Of Three Contrasting Grass Species, B M. Butler, J Hodgson
IGC Proceedings (1977-2023)
The innuence of continuous grazing management on leaf extension, leaf senescence and tiller density of 3 grass species with contrasting tillering rates, tiller size and growth habit was examined. Perennial ryegrass (Lolium perenne L. cv. Grasslands Nui), tall fescue (Festuca arundinacea Schreb, cv. Grasslands Roa) and Yorkshire fog (Holc,,s la11allls L. cv. Massey Bnsyn) were maintained in as near a steady state as possible at sward heights of 3-10 cm. The balance between leaf extension and senescence, and tiller density resulted in net extension per unit area being generally greatest at sward heights of- 5.5 cm in Yorkshire fog and …
Whole-Stand Carbon Gains And Nitrogen Distribution In Herbaceous Stands,
2024
Utrecht University
Whole-Stand Carbon Gains And Nitrogen Distribution In Herbaceous Stands, M.J A. Werger, T Hirose
IGC Proceedings (1977-2023)
We studied canopy structure and leaf nitrogen distribution in open and dense stands of tall dicot and monocot herbs and compared the results with simulated canopy performance under uniform and optimised leaf nitrogen distributions. Dense stands showed leaf nitrogen distributions that greatly differed from those of uniform distribution but did not completely match optimum distribution. In dense stands this led to strongly enhanced potential whole canopy carbon gains, while in open stands the leaf nitrogen distribution was not very important in this respect. Dense stands of monocots kept more leaf nitrogen in the lower parts of their canopies than is …
Advances In Genetic Transformation Of Plants,
2024
Purdue University
Advances In Genetic Transformation Of Plants, Thomas K. Hodges, Keerti S. Rathore, Jianying Peng
IGC Proceedings (1977-2023)
Many plant species, including both dicots and monocots, can now be genetically engineered with individual genes isolated from any source. Methods for delivery of foreign DNA into plant cells or protoplasts utilise Agrobacterium tumefaciens (and A. gazogenes), microinjection, polyethylene glycol, electroporation and particle guns. Advantages and disadvantages of each system are discussed. At present, all systems involve i11 vitra cell or tissue culture lo some extent, and this is the most difficult and variable aspect of plant genetic engineering. In addition, all systems suffer from random insertions of the foreign DNA into the plant genome. This requires Southern blot screening …
