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Dissertations / Theses on the topic 'Grasspea'

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Published: 4 June 2021

Last updated: 2 February 2022

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1

Chowdhury, Mahboob Alam. "Inheritance and linkage of morphological, isozyme and RAPD markers in grasspea." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq24008.pdf.

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2

Kearney, John P. "Wild Lathyrus species as genetic resource for improvement of Grasspea (L.sativus)." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239935.

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3

Reeder, John R., and Charlotte G. Reeder. "Notes on Arizona Grasses." University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/554184.

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4

Winkel, Von Kenneth. "Effects of seedbed modification, sowing depth and soil water on emergence of warm-season grasses." Diss., The University of Arizona, 1990. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1990_108_sip1_w.pdf&type=application/pdf.

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5

Mintenko, Anthony Scott. "Turfgrass evaluation of native grasses." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0025/MQ51771.pdf.

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6

Liebenberg, Louis Christian Cronje. "Studies on the seed-setting and on the germination of the seed of indigenous grasses with particular reference to methods for overcoming delayed germination." Pretoria : [s.n.], 1990. http://upetd.up.ac.za/thesis/available/etd-06042007-134353.

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7

Bäckström, Magnus. "Grassed swales for urban storm drainage /." Luleå, 2002. http://epubl.luth.se/1402-1544/2002/06/index.html.

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8

Leach, Carolyn R. "Studies on self-incompatibility in grasses /." Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09PH/09phl4341.pdf.

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9

Kopec, David, and Kai Umeda. "Overseeding Winter Grasses into Bermudagrass Turf." College of Agriculture, University of Arizona (Tucson, AZ), 2015. http://hdl.handle.net/10150/579520.

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2 pp.
Describes the proper timing of overseeding, selecting winter grasses, and procedures to prepare for overseeding with the amount of seed to use followed by irrigating, fertilizing, and mowing.

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10

Zhang, Jin-Tun. "Ecological relationships of some montane grasses." Thesis, Bangor University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292852.

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11

Howard, Claire L. "Comparative ecology of four brome grasses." Thesis, University of Liverpool, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316635.

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12

Bäckström, Magnus. "Grassed swales for urban storm drainage." Doctoral thesis, Luleå, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25702.

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This thesis investigates the environmental, economic and functional aspects of using grassed swales for the conveyance and treatment of stormwater. A grassed swale is a shallow, grass-lined channel. The environmental aspects relate to the transport and retention of stormwater pollutants in grassed swales and the utilisation of natural resources for the construction and operation of different stormwater transport systems (e.g. grassed swales). The economic aspects considered are the costs needed to construct and operate stormwater transport systems. The investigated functional aspects of grassed swales relate to conveyance and infiltration. Two full-scale studies were performed: 1) a study of sediment removal in a 70-m long grassed swale (Gammelstad, Luleå) and 2) a study of the transport and retention of suspended solids and heavy metals in a 110-m roadside grassed swale (Södra Hamnleden, Luleå). Particle trapping and flow conditions in different grassed swales were analysed using a standardised runoff event simulation procedure where water and road sediment were mixed in a 1-m3 tank and then pumped into a swale. The utilisation of resources of a pipe system and a swale system was analysed. It was suggested that the use of physical resources (in terms of exergy) could be one indicator on environmental sustainability and that a cost analysis would measure how society (human beings) valued these resources. Grassed swales with fully developed turfs and mild bottom slopes (<7%) provide high flow resistance. Grassed swales require lower amounts of natural resources, in terms of exergy, than a comparable stormwater pipe system. A grassed swale is more cost-efficient than a pipe system in areas with low land prices and good topsoil. The variations in pollutant removal efficiency of a grassed swale could be explained by the variations in influent pollutant concentrations. In general, grassed swales may be regarded as facilities that even out the peaks in pollutant loads without being capable of producing consistent high removal rates. Low to moderate removal efficiencies could be expected for heavy metals, especially metals in solution (i.e. the dissolved phase). Pollutant load reductions in grassed swales may be considerable over an extended time period with several successive rain events. This thesis shows that there are exponential relationships between grassed swale sediment removal potential and mean hydraulic detention time. Furthermore, surface loading or specific swale area (i.e. the ratio between swale area and contributing impervious drainage area) might be used as design parameters when constructing grassed swales for pollution control.
Godkänd; 2002; 20061113 (haneit)

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13

Hands, Philip Stuart. "Comparative grain development in temperate grasses." Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/27807.

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Temperate or pooid cereal crops, such as wheat, barley and oat, represent a major world food source much of which is attributable to the storage capabilities of the cereal endosperm and influences of domestication selection. Brachypodium distachyon has recently become established as a genome-sequenced model system and the first wild member of the Pooideae be studied in detail. We provide the first detailed description of grain development in Brachypodium assessing its suitability as a model for grain development in crop species. Cellular and molecular mapping of developing Brachypodium endosperm domains reveals significant differences in aleurone differentiation reflecting differences in grain filling and endosperm storage reserves. We extend this survey of grain morphology and endosperm organisation to a wider sample of the Pooideae incorporating both wild and cultivated species. Focusing on the functionally important aleurone domains, distinct patterns of grain tissue organisation are described. Results indicate that organizational features are correlated to species’ ecological and grain quality characters and that the modified aleurone region, absent in Brachypodium, may be a feature of only a subset of cereals, specifically the Triticeae tribe. A more systematic candidate gene approach focusing on transcription factors was initiated in attempts to find the genes underpinning this variation. The identification of orthologous key regulatory genes with both similar and contrasting patterns of expression provides information on the differences and conservation of grain developmental pathways amongst the Pooideae. To investigate function of candidate genes, publically available insertional mutants for major MADS-box and YABBY genes were obtained and characterized, while simultaneously attempting to establish genetic transformation protocols to enable RNAi analyses of other candidate genes.

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14

Verboom, George Anthony. "Ovular features of African arundinoid grasses." Thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/26032.

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15

Engelbrecht, Nicolaas Carel Marthinus. "Foggage value of sub-tropical grasses." Diss., University of Pretoria, 2002. http://hdl.handle.net/2263/28505.

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The use of foggage as winter feed for animal maintenance is unlikely to totally replace hay and/or silage, but should be used as an alternative for the early winter. The most important objective in producing foggage is to feed animals to at least maintain body weight through the winter season. As foggage is generally not a high quality feed, it usually can not be used for producing animals without supplementation. Using foggage can also mininise expensive inputs, such as labour and machinery. This is the single most outstanding advantage of using pasture foggage over hay, haylage, crop residues or silage. Although pastures also have establishment and fertilizer costs, these are less than costs associated with intensive annual crops. Many pastures are also perennial, which means less establishment costs. This emphasises the importance for less intensive farming systems. Depending on what the objectives of the farmer are, he can manage foggage to produce a high yield with a lower quality or vice versa. Thus it is critical to maintain a balance between yield and quality. Foggage quality was inversely related to the growing season after the pasture was closed-up and thus the quality will be lower with earlier closing-up time. Fertilisation, especially with nitrogen, will increase the nutritive value of the product (6% - 12%CP). The aim of this study was to determine which pasture provides the best foggage in different scenarios. The conclusion is, therefore, that a farmer must first decide on his management plan and where his foggage will fit in. Then it is recommended to choose the species (or accession) that is best adapted to his specific area of farming. Silk sorghum and Coastcross II had the best yields recorded. Smutsfinger grass was very palatable, had high digestibility and would, therefore, be recommended for quality in the higher rainfall eastern parts of the country. Because of their drought resistance, Molopo and Kleingrass will be recommended for the warmer areas with less rainfall and Molopo especially for small farmers who lack overall grazing management skills or infrastructure.
Dissertation (MSc (Agric) Pasture Science)--University of Pretoria, 2002.
Plant Production and Soil Science
unrestricted

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16

Frole, Kristen Marie. "Drought responses of C3 and C4 (NADP-ME) Panicoid grasses." Thesis, Rhodes University, 2008. http://eprints.ru.ac.za/1716/.

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17

Baluta, Daniel. "Competitive hierarchies amongst twelve native prairie grasses." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ41679.pdf.

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18

Baines, R. N. "Interactions between white clover and pasture grasses." Thesis, University of Reading, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383598.

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19

Seffen, Mongi. "Synthèse catalytique d'amines grasses à partir d'esters." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37601130t.

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20

Hackel, Jan. "Molecular biogeography of grasses and tropical grasslands." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30222.

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Les graminées (Poaceae) sont une très grande famille cosmopolite de plantes. Dans la thèse présentée ici, j'ai utilisé des méthodes moléculaires pour analyser leur histoire biogéographique. Le premier chapitre s'intéresse aux déterminants de la dispersion dans la sous-tribu tempérée Loliinae. La distance apparaît comme le facteur dominant. Le deuxième chapitre présente une analyse des origines des graminées de Madagascar. Les résultats montrent deux grandes radiations in situ de graminées C3 et une immigration répétée de graminées C4, soutenant l'existence de savanes malgaches avant la présence humaine. Le troisième chapitre résout la position d'une lignée C3 d'Asie à l'aide de la phylogénomique, avec des implications pour l'évolution de la photosynthèse C4 et des savanes tropicales. Le quatrième chapitre présente une méthode de méta-barcoding pour l'analyse des communautés d'endophytes fongiques associées aux graminées à Madagascar, démontrant des limitations méthodologiques
Grasses (Poaceae) are a large, cosmopolitan plant family. In this dissertation, I used molecular methods to study their biogeographic history. The first chapter focuses on determinants of lineage dispersal in the temperate subtribe Loliinae, with distance found to be the dominant factor. The second chapter analyses the origins of Madagascar's grass flora. Two large in situ radiations of C3 grasses were found while C4 grasses immigrated more frequently and support the pre-human presence of grasslands in Madagascar. The third chapter resolves relationships of an Asian C3 lineage using phylogenomic methods, with implications for C4 photosynthesis evolution and the assembly of tropical grasslands. The fourth and final chapter developed a metabarcoding method for the analysis of fungal endophyte communities associated to grasses in Madagascar, with results highlighting methodological limitations

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21

Knowles, Tim C., and Michael J. Ottman. "Sudangrass Hay Production in the Irrigated Deserts of Arizona and California." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/147028.

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22

Rudmann, Silvia Graciela. "Resource utilization of C4 tropical grasses at elevated CO2 /." View thesis View thesis, 2000. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030428.144722/index.html.

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Thesis (Ph.D.) -- University of Western Sydney, Hawkesbury, 2000.
Thesis submitted in fulfilment of the requirement for the degree of Doctor of Philosophy, Centre For Horticulture and Plant Sciences, University of Western Sydney, 2000. Bibliography : leaves 215-231.

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23

TAISNE, PHILIPPE. "Les cosmetiques de la peau grasse." Lille 2, 1988. http://www.theses.fr/1988LIL2M074.

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24

Martin, Tarryn. "Photosynthetic and evolutionary determinants of the response of selected C3 and C4 (NADP-ME) grasses to fire." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1003780.

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Species possess characteristics that are considered adapted to burning and these allow them to outcompete species and dominate in fire prone environments. It has therefore been proposed that fire might have played a critical role in the observed expansion of the grasslands, during the late Miocene. The aim of this study was (i) to investigate whether plant response to fire was a result of physiology or (ii) whether it was due to phylogenetic history. This was achieved by doing a pair-wise comparison between Panicoideae (and Panicoideae) and non-Panicoideae (Danthonioideae and Aristidoideae) species. Pre-fire characteristics, that would enhance fire frequency and assist with plant recovery after burning, were compared across phylogenies and photosynthetic type. Post fire plant recovery was then followed in a field and pot comparison which examined the re-growth of the leaf canopy area, leaf mass, above-ground biomass and the cost of this to the below-ground biomass. The pre-fire characteristics showed both a photosynthetic and phylogenetic response. It was found that the species showed a greater canopy death during winter and had a lower moisture content than the species. These characteristics would potentially contribute towards a larger fuel load in the species. However, the comparison of the dead standing biomass at the end of winter and the below-ground biomass, showed a phylogenetic response with the Panicoideae having a proportionally larger dead standing biomass and below-ground biomass than the non-Panicoideae. These results suggest that not only did the Panicoideae have a larger potential fuel load but that they also shunted carbon below-ground, enabling a fast recovery after being burned. The post-fire results were more strongly determined by phylogeny than by photosynthetic type. The Panicoideae recovered faster and more completely than the non-Panicoideae grasses, possibly contributing to their success and expansion under conditions of increased fire frequency. Although recovery of the and Panicoideae were similar, frequently burnt grasslands are dominated by the Panicoideae. Hence, this dominance cannot be explained by differences in their fire responses and may be determined by the post-fire environmental conditions that potentially advantage species possessing the photosynthetic pathway. Panicoideae dominance is limited to mesic environments where fire is the likely driver of grassland expansion while more arid environments are dominated by non-Panicoideae species. Representative species from these non-Panicoid subfamilies showed poor recovery after fire. This suggests that factors other than fire were the likely drivers of these xeric grassland expansions. The ability of these subfamilies, and particularly the species, to cope with drought remains a likely selective mechanism that requires further research.

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25

Livingston, Margaret. "Factors influencing germination and establishment of Arizona cottontop, bush muhly, and plains lovegrass in southern Arizona." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/186068.

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Germination and establishment was evaluated in Arizona cottontop (Digitaria californica (Benth.) Chase), bush muhly (Muhlenbergia porteri Scribn.) and plains lovegrass (Eragrostis intermedia Hitchc.) from southern Arizona. Germination was determined in different aged seed harvested from native and irrigated plots of various populations. Results indicated variability in germination characteristics of study species that appeared unrelated to afterripening or dormancy. Germination ranged from 62 to 96% for Arizona cottontop, 34 to 99% for plains lovegrass, and 75 to 99% for bush muhly. Bush muhly had highest average velocity of germination (58.0 ± 4.1), followed by plains lovegrass (35.9 ± 1.91), and Arizona cottontop (31.4 ± 1.13). Effects of 3 surface treatments (furrows, gravel, litter) and 2 cultivation treatments on establishment of study species and yellow bluestem (Bothriochloa ischaemum (L.) Keng var. ischaemum) was investigated in the field. Bush muhly did not emerge and plains lovegrass had minimal emergence. Arizona cottontop had similar emergence in cultivated and uncultivated plots whereas yellow bluestem had greater emergence in cultivated plots. Litter promoted greater survival of Arizona cottontop. Lower survival in furrows may have resulted from fewer days with available soil moisture and interference from greater density of non-seeded species. Soil covers appear to positively influence survival rather than emergence. Effect of rainfall distribution on germination was investigated using 2 seed retrieval methods. Arizona cottontop and bush muhly germinated after at least 3 days of available soil moisture. Plains lovegrass seeds did not germinate in the field but retrieved seeds had 83% germination, possibly due to light exposure under laboratory conditions. Another study determined whether species have different density and cover under overstory species compared to open areas. Arizona cottontop had either greater, less, or no differences in density under canopied versus open areas. Cover of Arizona cottontop was greater or similar among canopied and open areas. Plains lovegrass had lower or similar density and cover under canopies than in open areas. Bush muhly had greater density and cover under canopies. Overall, studies suggested that species are easily germinated, but accept relatively narrow ranges of environmental conditions for establishment. Establishment may be enhanced by sowing species when rainfall is consistent, extending available moisture through use of soil covers, or mimicking microsites where a species occurs naturally.

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26

Puhr, RoseMary Allyson. "Evolution of the Sparse inflorescence1 lineage in grasses." Thesis, California State University, Long Beach, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1523069.

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Auxin is a phytohormone that has long been known to control many aspects of plant growth and development. The YUCCA (YUC) gene family is a large group of genes that catalyze auxin biosynthesis and have been shown to be critical for vegetative growth and inflorescence development in grasses. There is genetic redundancy present with Arabidopsis YUCs, but in Zea mays (maize), a single gene knockout of ZmSPI1 causes a severe inflorescence phenotype. Since Oryza sativa (rice), another grass species, does not show an inflorescence phenotype when OsYUC1/SPI1 is knocked down, SPI1 appears to have undergone an evolutionary shift in function within the grass family. This study shows that SPI1 expression in PACMAD (Panicoideae, Arundinoideae, Chlorodoideae, Micrairoideae, Aristidoideae, and Danthoniodeae subfamilies) clade grasses Sorghum bicolor and Setaria italica occurs at sites of inflorescence branching and is consistent with maize, but in BEP (Bambusoideae, Ehrhartoideae, and Pooideae subfamilies) clade grasses rice and Brachypodium distachyon SPI1 shifts from localized expression to more generalized expression and potentially becomes weaker. Artificial microRNA (amiRNA) knockdowns of SPI1 expression in Brachypodium did not show a phenotype when expression was reduced to 28.01% (+/- 6.39%) of wild type. In rice and Brachypodium, other YUC genes were shown to be expressed in the inflorescence by quantitative RT-PCR (qPCR), suggesting YUC proteins are more redundant in BEP grasses such as B. distachyon and O. sativa, than in maize and potentially its relatives.

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27

Rodgers, Cassandra Sue Anderson Roger C. "Establishment of prairie grasses on strip mine spoils." Normal, Ill. Illinois State University, 1987. http://wwwlib.umi.com/cr/ilstu/fullcit?p8806867.

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Thesis (Ph. D.)--Illinois State University, 1987.
Title from title page screen, viewed August 31, 2005. Dissertation Committee: Roger C. Anderson (chair), Dale E. Brickenholz, Anthony E. Liberta, Alan J. Katz, Jerome R. Cain. Includes bibliographical references (leaves 91-102) and abstract. Also available in print.

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28

Babu, Jacob. "Bioactive Chemicals of Importance in Endophyte-Infected Grasses." The University of Waikato, 2009. http://hdl.handle.net/10289/2608.

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Janthitrems are believed to be involved in the observed sporadic cases of AR37- infected perennial ryegrass staggers. Investigations into the role of janthitrems in perennial ryegrass staggers are difficult as isolation of the compounds from the ryegrass is hindered by the inherent instability of these compounds. Therefore attempts were made to isolate janthitrems from an alternative source, allowing these janthitrem analogues to be used as surrogates for endophyte produced janthitrems. Analysis of a series of Penicillium janthinellum cultures revealed the presence of janthitrems in a number of strains, including janthitrem B, janthitrem C and two novel janthitrem compounds. Detailed one- and two-dimensional NMR and mass spectral techniques identified the two novel compounds as 11,12- epoxyjanthitrems B and C, which were subsequently given the trivial names janthitrems A and D, respectively. Janthitrems B and C were isolated and identified by NMR and revisions of some previously reported chemical shift assignments were proposed. In addition to the janthitrems, penitrems were also identified in two strains of P. janthinellum. The isolated janthitrem B was utilised for the development of efficient extraction procedures, and for the determination of ideal storage conditions for janthitrem compounds. A method for the extraction and isolation of janthitrem B from a P. janthinellum culture was developed and optimised to yield 6 mg of janthitrem B from 900 mL of fungal culture in two days. Stability studies of janthitrem B indicated the ideal storage condition which minimised degradation was dry at −80 C where only 7% sample loss was observed over 300 days. Bioactivity studies of janthitrems A and B found these compounds to be tremorgenic to mice, with janthitrem A (an epoxyjanthitrem) inducing more severe tremors than janthitrem B. Insect testing also showed that both janthitrems A and B displayed anti-insect activity to porina larvae. Since the epoxyjanthitrems, which are associated with AR37 endophyte-infected ryegrass, were also shown to be tremorgenic and to display anti-insect activity, the insect resistance and the sporadic cases of ryegrass staggers displayed by AR37 may be related to the presence of epoxyjanthitrem compounds. LC-UV-MS analysis of janthitrems A-D, penitrems A-F, lolitrem B, paspalinine, paxilline and terpendole C found these indole-diterpenoids to be more sensitive by analysis using an APCI source as opposed to an ESI source. APCI negative ion LC-UV-MS required source induced dissociation in combination with increased collision energy to suppress an acetate adduct peak, sourced from the acetic acid buffer. Negative ion MS2 and MS3 data produced more informative fragments compared to the conventional positive ion MS2 and MS3 data. The availability of both positive and negative ion LC-UV-MS methodologies will allow future endophyte products to be more thoroughly screened for different classes of secondary metabolites. Extracts of mouldy walnuts were analysed for the presence of tremorgenic mycotoxins after a dog was found to exhibit symptoms characteristic of tremorgenic mycotoxicosis. LC-UV-MS analysis of the mouldy walnuts identified the tremorgenic mycotoxins penitrems A-F, thus confirming the veterinarian's tentative diagnosis of canine tremorgenic mycotoxicosis the first reported case in New Zealand.

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29

Vicari, Mark. "Interactions between grasses, their fungal invaders, and herbivores." Thesis, Lancaster University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264680.

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30

Thomas, Alan. "Low temperature growth in forage grasses and cereals." Thesis, Bangor University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278780.

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31

Jones, Valerie. "Physiological response of turf grasses to trampling pressure." Thesis, Keele University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328049.

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Some responses of turfgrasses to trampling stress were examined using simulated trampling methods in greenhouse and laboratory studies. Subsidiary experimental field studies indicated that the laboratory results were relevant to the natural situation. Shoot yield, 002 exchange and water relation parameters were measured, concentrating on the short term response to simulated trampling. A range of turf grass species and cultivars were included so comparison of wear tolerant and wear susceptible cultivar response was possible. An electrolyte release method was developed to ascertain plant injury following simulated trampling. Differences in injury index were related to levels of wear tolerance of the species and cultivars. Shoot yield was reduced with simulated trampling in all species and cultivars tested. Decrease in shoot yield correlated significantly with increasing intensity of trampling and increased injury index. Differences in amount of shoot decrease between species and cultivars related to ratings of wear tolerance in the literature. Net photosynthesis of Lolium perenne S23 decreased significantly with simulated trampling and a slight increase in respiration was recorded. Net photosynthesis correlated with injury level. Continuous monitoring over the initial few hours after treatment revealed a sharp decline in photosynthesis rates, followed by gradual recovery. Selected cultivars had a lower shoot water content two hours after treatment, the higher the intensity of simulated trampling the lower was the water content. SEM studies indicated disruption of epicuticular wax, therefore reducing cuticular resistance to water loss. Transpiration rates were reduced with simulated trampling and calculations showed a reduced hydraulic conductivity. These findings were related to relevant observations of response of plants to other stresses, particularly wind. A model is presented suggesting how observed and hypothetical responses, both short term and long term, may contribute to the survival or death of grass following trampling.

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32

Zare, Abbas Ghamari. "Anther culture in intergeneric hybrids of forage grasses." Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417963.

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33

Masubelele, Mmoto Leonard. "Decomposition of grasses in a South African savanna." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/6132.

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Includes bibliographical references (leaves 108-124)
Tropical and subtropical grasslands ecologists have ignored decomposition, because of the important role it plays in nutrient cycling, in terms of understanding how grass litter gets to the soil during the dry season. The major flaw is in the methods employed to investigate decomposition. In the prairies and steppes, litterbag methods employed investigate decomposition when litter is on the soil, even though the importance of carryover from standing litter is recognized. Standing litter results in high carryover which slows down decomposition thereby hindering productivity in the next growing season. I therefore decided to investigate the processes of photodegradation and microbial decomposition, as well as carryover and also how these processes differ between mesic and semi-arid grasslands. Since previous studies suggest that tallgrass prairies experience more carryover and slower decomposition than shortgrass prairies, I therefore hypothesized in this thesis that mesic grasslands will experience carryover and slower decomposition than semi-arid grasslands.

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34

Voshell, Stephanie. "Evolutionary history of the canary grasses (Phalaris, Poaceae)." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/64289.

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Canary grasses (Phalaris, Poaceae) include 21 species widely distributed throughout temperate and subtropical regions of the world with centers of diversity in the Mediterranean Basin and western North America. The genus contains annual/perennial, endemic/cosmopolitan, wild, and invasive species with basic numbers of x=6 (diploid) and x=7 (diploid/tetraploid/hexaploid). The latter display vastly greater speciation and geographic distribution. These attributes make Phalaris an ideal platform to study species diversification, dispersal, historic hybridization, polyploidy events, and chromosome evolution in the grasses. This body of research presents the first molecular phylogenetic and phylogeographic reconstruction of the genus based on the nuclear ITS and plastid trnT-F DNA regions allowing species relationships and the importance of polyploidy in speciation to be assessed. Divergence dates for the genus were determined using Bayesian methods (BEAST, version 1.6.2) and historic patterns of dispersal were analyzed with RASP (version 2.1b). Self-incompatibility and the feasibility of hybridization between major groups within the genus were studied with a series of greenhouse experiments. Acetocarmine and fluorescent staining techniques were used to study the morphology of the chromosomes in a phylogenetic context and the nuclear DNA content (C values) was quantified using flow cytometry. Four major clades were revealed in the genus with cytological and geographic affinities leading to the establishment of two subgenera and four sections in the first comprehensive infrageneric treatment of Phalaris. Divergence dating revealed a Miocene emergence (20.6-8.4 MYA) for the genus which is concurrent with studies of other genera in the Aveneae tribe. The hypothesis stating that Phalaris originated in the Mediterranean Basin and dispersed to the New World via a western route leading to a secondary center of diversification in western North America was supported by phylogeographic and cytological analyses. An empirical study comparing the weight, length, and width of the florets by morphological type and cytotype revealed significant differences that support a dispersal advantage among the New World and Arundinacea species. The x=6 species displayed greater intraspecific C value variation, higher DNA content per haploid chromosome set, and a distinct karyotype compared with the x=7 species indicating a complex history of chromosome evolution.
Ph. D.

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Deletic, Ana. "Sediment behaviour in overland flow over grassed areas." Thesis, University of Aberdeen, 2000. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU602013.

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Grassed areas, such as grass filter strips (GFS), and grassed swales, have been used extensively for the surface water protection against erosion and polluted runoffs. In order to use grass properly for water purification, it is important to understand and model sediment behaviour in runoff over grassed areas. This project was concerned with sediment transport in non-submerged overland flow through grass. The work contains several distinctive parts, as discussed below. A broad based literature study was carried out. It was found that the literature on sediment transport in shallow non-submerged flow through grass is very restricted, although a lot has been published on GFS performance in rural environment. Usually, the published field works have not been focused on the processes involved, but rather on the overall GFS performance. Therefore, the methods currently used for modelling of sediment transport through grass are very poor. To overcome these problems the literature on related subjects was also incorporated in the study. A laboratory investigation was carried out in a flume at the Aberdeen University Fluids Laboratory, aimed at development of a new method for assessment of sediment transport in non-submerged, steady, and uniform flow through grass. A field study was conducted in order to verify the findings of the laboratory study and provide data for verification of a complex dynamic model developed in the next stage of the project. A grassed channel was formed at a well established and maintained lawn at the University campus. Three experiments were carried out with clean water (no sediment present) in order to investigate infiltration and overland flow through grass. Using similar equipment to that used in the laboratory study, six experiments were carried out in the same way as the laboratory deposition experiments. They confirmed the findings of the laboratory study. The data already gathered during both laboratory and field study may be used for various improvements of TRAVA, but new studies are needed for its further verification and development.

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Loubser, Dalene. "Molecular tagging of Thinopyrum distichum chromosomes involved in salt tolerance." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/53754.

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Thesis (MSc)--Stellenbosch University, 2004.
ENGLISH ABSTRACT: Much has been written about the effects of soil salinity on plant growth. Its devastating effects have already been reported 2000 years BC. In the 21· century an alarming 80 million hectares of cultivated land area are affected by salt (Munns, 2002a) and represent a growing threat to agriculture. Salt tolerance is a complex trait moderately expressed in only a few plant genotypes (Ruiz, 2001). An attempt to transfer salt tolerance genes from the wild grass, Thinopyrum distichum, to triticale and éommon wheat was initiated by Marais and Marais (2003). A study of Th. distichum x rye hybrids enabled the authors to identify chromosomes 2Jld , 3Jld , 4Jld and SJld as being involved in the determination of salt tolerance. Indirect (yet unconfirmed) evidence suggested that 7Jld might also have a role. A programme aiming to transfer regions of the critical chromosomes to homoeologous triticale chromosomes, which relies heavily on the use of molecular markers, was launched. While an RFLP marker is available for each of the Thinopyrum chromosomes, these are not suited for the screening of large numbers of segregates. This study therefore represents an attempt to convert the RFLP markers into less time consuming and cost-effective SCAR markers. The published DNA sequences of the RFLP probes in question were used as templates to design PCR primers. The PCR reactions were optimised using DNA of Th. distichum, rye and their FI hybrid. When Thinopyrum specific amplification products were obtained, the primers were also tested on a panel of genotypes with and without the target chromosomes. Seemingly polymorphic bands were confirmed by Southern blotting and hybridisation with the corresponding RFLP probes. The primers were also tested on a panel of genotypes that included 'Rex' triticale to ensure that they would also detect a difference in a triticale genetic background during transfer. Polymorphic bands were then isolated and sequenced to further refine the markers. In certain eases, sequences of the same fragment amplified in triticale ('Rex') and Thinopyrum were aligned in an attempt to design more specific markers. Using this approach, it was possible to develop chromosome specific SCARs for Thinopyrum chromosomes 3Jld and 7J2 d . Three and one set(s) of PCR markers, respectively, have been developed and can be used to unequivocally detect the Thinopyrum chromosomes involved in salt tolerance against a triticale background. A SCAR marker was also found for chromosome 6J. Thus, an attempt was made to convert thirteen RFLP probes to SCAR markers. Only three were successfully converted. The main reason for the low success rate is the syntenic relationships between the genomes of the different cereals that made it an arduous- task to find discriminating primer sets. Based on the results obtained, an adapted procedure is suggested for future attempts to develop chromosome specific markers utilizing published sequence information that was obtained for a different species.
AFRIKAANSE OPSOMMING: Baie is al geskryf oor die uitwerking van grond versouting op plantproduksie. Die vernietigende gevolge van versouting is alreeds 2000 jaar VC gerapporteer. In die 21* eeu is 'n geraamde 80 miljoen hektaar (Munns, 2002a) bewerkte land-area sout-geaffekteerd. Die ontstellende verwikkelinge verteenwoordig 'n groeiende bedreiging vir die landbou. Soutverdraagsaamheid is 'n komplekse kenmerk en slegs enkele plantgenotipes met matige verdraagsaamheid kon nog ontwikkel word (Ruiz, 2001). 'n Poging om soutverdraagsaamheidsgene vanaf die wilde gras, Thinopyrum distichum, na triticale en gewone koring oor te dra, is deur Marais en Marais (2003) geïnisieer. 'n Studie van Th. distichum x rog hibriede het die skrywers in staat gestelom chromosome (2Jld, 3Jld, 4Jld en SJld) wat bydra to soutverdraagsaamheid te identifiseer. Indirekte (maar onbevestigde) aanduidings is gevind dat 7J1dook' n rol mag speel. 'n Program is daarna geloods om segmente van chromosome na homoeoloë triticale chromosome oor te dra, 'n onderneming wat swaar steun op die gebruik van molekulêre merkers. Alhoewel daar'n RFLP merker beskikbaar is vir elk van die Thinopyrum chromosome, is hierdie merkers nie geskik vir die sifting van groot getalle segregate nie. Hierdie studie verteenwoordig 'n poging om die RFLP merkers om te skakel na 'n minder tydrowende en meer koste-effektiewe SCAR merkers. Die gepubliseerde DNS-volgordes van die betrokke RFLP peilers is as templaat gebruik om PKR inleiers te ontwerp. Die PKR reaksies is geoptimiseer deur gebruik te maak van DNS van Th. distichum. rog en hulle FI hibried. In gevalle waar Thinopyrum spesifieke amplifikasie produkte verkry is, is die inleiers ook getoets op 'n paneel van genotipes met en sonder die teikenchromosoom. Skynbare polimorfiese bande is bevestig deur 'n 'Southern' klad te maak en te hibridiseer met die tersaaklike RFLP peiler. Die inleiers is ook getoets op 'n paneel van genotipes waarby 'Rex' triticale ingesluit was om te verseker dat dit ook verskille in 'n triticale genetiese agtergrond opspoor (nodig tydens oordrag). Polimorfiese bande is verder verfyn. Dit is geïsoleer en die DNS-volgorde daarvan is bepaal. Tn sekere gevalle is ooreenstemmende fragmente geamplifiseer in triticale ('Rex') en Thinopyrum. Die volgordes is dan bepaal en met mekaar vergelyk in 'n poging om meer spesifieke merkers te ontwerp. Met die gebruik van hierdie benadering was dit moontlik om chromosoom-spesifieke SCAR-merkers vir die Thinopyrum chromosome 3Jld en 7J2d te ontwikkel. Drie en een stel(le) PKR merkers is onderskeidelik ontwikkel en kan gebruik word om ondubbelsinnig te bepaal of die betrokke Thinopyrum chromosoom segregeer in 'n triticale kruising. 'n SCAR merker is ook gevind vir chromosoom 6J. Dus, daar is probeer om dertien RFLP peilers na SCAR merkers om te skakel. Slegs drie van die pogings was suksesvol. Die hoofrede vir die lae sukseskoers is die hoë graad van sintenie tussen die genome van die verskillende grane wat dit 'n moeilike taak gemaak het om diskriminerende inleierstelle te ontwerp. Op grond van die resultate word 'n ietwat gewysigde prosedure vir die toekomstige pogings om chromosoom-spesifieke merkers te ontwerp met gebruik van gepubliseerde volgorde inligting vanaf' n ander spesie, voorgestel.

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37

Cao, Mingshu. "Molecular cytogenetic analysis of genomes between Festuca mairei and Lolium perenne /." free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3012953.

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38

Day, Toby Richard. "Intermountain West native and adapted grass species and their management for turfgrass applications." Thesis, Montana State University, 2006. http://etd.lib.montana.edu/etd/2006/day/DayT0806.pdf.

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39

Taube, Melanie I. "Establishment of grassland forbs in modified urban environments /." Connect to thesis, 1998. http://eprints.unimelb.edu.au/archive/00000306.

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40

Milnes, Katharine Judith. "The responses of Briza media and Koeleria macrantha to drought and changes in nitrogen supply." Thesis, Lancaster University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301821.

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41

Shrestha, Sangita. "Molecular systematics of weedy sporobolus species of Australia /." St. Lucia, Qld, 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16398.pdf.

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42

Bruner, Joe L. "Systematics of the Schizachyrium Scoparium (Poaceae) complex in North America /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu148733076121936.

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43

Ozenne, Catherine. "Biofaçonnement de la matière grasse du lait." Montpellier 2, 1993. http://www.theses.fr/1993MON20159.

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La selectivite de cinq lipases a ete determinee par l'hydrolyse de triglycerides de matiere grasse laitiere. L'aptitude a la transacylation de ces preparations enzymatiques a ensuite ete evaluee sur un milieu test. Enfin, le biocatalyseur le plus performant a ete mis en uvre en presence de matiere grasse laitiere et d'acides gras alimentaires

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44

Marais, D. "Water use of perennial summer grasses in South Africa." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-11082006-135400.

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Thesis Ph.D. (Agric.(Pasture science))-University of Pretoria, 2005.
Included summaries in Afrikaans and English. Includes bibliographical references. Available on the Internet via the World Wide Web.

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45

Rudmann, Silvia G., of Western Sydney Hawkesbury University, Faculty of Science and Technology, and Centre for Horticulture and Plant Sciences. "Resource utilization of C4 tropical grasses at elevated CO2." THESIS_FST_HPS_Rudmann_S.xml, 2000. http://handle.uws.edu.au:8081/1959.7/65.

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The atmospheric (CO2) partial pressure is expected to continue to increase and the scenario is that the CO2 partial pressure will reach 50-70 Pa during the 21st century.The rise in CO2 will have a direct influence on plant growth and development because CO2 is the primary substrate for photosynthesis.The aim of the studies described in this thesis was to investigate the response of grasses belonging to two subtypes to a range of CO2 partial pressures under conditions where light intensity, water and N supplies were varied.Two species which are naturalized in Australia, Panicum coloratum (NAD-ME) and Cenchrus ciliaris (NADP-ME) were chosen for a series of experiments conducted in matched growth chambers. The response of C4 plants is particularly important for Australia because they dominate the tropical grasslands that occupy 75% of the continent and form the basis for the pasture industry. Following the extensive research conducted in this study, it can be concluded that the inevitable rise in atmospheric CO2 partial pressure will increase the growth of C4 grasses when other resources are not limiting.Growth of C4 grasses will be stimulated to a greater extent under conditions of drought.
Doctor of Philsophy (PhD)

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46

Gaskin, Sharyn, and sharyn gaskin@flinders edu au. "Rhizoremediation of hydrocarbon contaminated soil using Australian native grasses." Flinders University. Medicine, 2009. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20090820.111303.

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The breakdown of contaminants in soil resulting from microbial activity that is enhanced in the presence of the plant root zone, rhizosphere, has been termed rhizoremediation. To date, Australian native plants have not been assessed for their hydrocarbon rhizoremediation potential. The use of native plants offers an economically feasible and environmentally sustainable cleanup option for the rehabilitation and restoration of hydrocarbon contaminated sites in Australia. The aim of the study was to evaluate the potential of Australian native grass species for the rhizoremediation of aliphatic hydrocarbon contaminated soil from a mine site. Candidate Australian native grass species Poaceae were selected following the development of essential and desirable growth criteria. Nine perennial Australian grasses were evaluated for seedling emergence in sandy loam soil sourced from a mine site which was artificially contaminated with a 60:40 diesel/oil mix at concentrations of 30 000 mg/kg, 10 000 mg/kg, 5 000 mg/kg and 0 mg/kg control. Seedling emergence was not adversely affected by the presence of hydrocarbon contamination at the exposed concentrations for eight of the nine species studied p > 0.05. Three promising species were assessed for relative growth performance in diesel/oil contaminated 10 000 mg/kg, 5 000 mg/kg and uncontaminated control soils in greenhouse studies to assess their tolerance of aliphatic hydrocarbon contaminated soil. Cymbopogon ambiguus Lemon Scented grass is a summer growing perennial with widespread distribution throughout Australia including the region where the mine site is situated. Brachiaria decumbens Signal grass naturalised - is adapted to humid tropical areas of Australia and is native to the site and sourced from seed banks. Microlaena stipoides Weeping grass var. Griffin is a cool season grass, widely distributed throughout Australia in moister regions. The three evaluated species survived for 120 days in the diesel/oil contaminated soil at the exposed concentrations without adverse growth affect p > 0.05. In some instances e.g. C. ambiguus growth stimulation occurred in the presence of contamination producing significantly more root biomass compared with the control p < 0.0001. Most hydrocarbon degradation is believed to occur through microbial processes, and so the plant-associated microbial community was examined in the three tolerant species. The assessment of the influence of grass on the abundance and activity of microorganisms in the rhizosphere revealed species-specific plant-induced changes in the soil microbial community. Selective enrichment of hydrocarbon degrading microorganisms was demonstrated in the rhizosphere soil of the Australian grasses tested, to varying degrees. C. ambiguus appeared to have the greatest influence on stimulation of hydrocarbon degrading microorganisms, followed by the cool season grass M. stipoides. B. decumbens showed consistently lower numbers of hydrocarbon degrading microorganisms in rhizosphere soil over time compared to the other two species p < 0.01. The influence of grasses on microbial community structure - defined as community DNA fingerprint - in diesel/oil contaminated soil suggested no new microbial population was favoured by the grasses - qualitative shift - rather there were relative quantitative changes in existing members of the microbial population. Soil lipase activity did not appear to be an optimal bioindicator of rhizoremediation and may encompass total soil microbial activity not exclusively the hydrocarbon degrading microorganisms of interest. The assessment of biodegradation of hydrocarbons in soil is essential to characterise the effectiveness of plant species in rhizoremediation. Residual diesel and oil concentrations as total petroleum hydrocarbons, TPH were measured using Gas Chromatography. The presence of single species successfully enhanced the removal of hydrocarbons from soil for all species. All showed significantly lower residual hydrocarbon concentrations than those in unplanted soil after 100 days p < 0.01. Significantly, it was not necessary to add N and P to achieve up to 90% reduction in hydrocarbon concentrations in the soil. The relative performance of each grass species varied. In soil planted with C. ambiguus hydrocarbon concentrations were reduced faster and to a greater extent than the other species studied, from 10 000 mg/kg to approximately 1 100 mg/kg TPH, 88% removal. Similar endpoint success was recorded for M. stipoides which facilitated 80% reduction in hydrocarbon concentrations. Interestingly, B. decumbens, the only naturalised species, did not perform as well as the other species, although still significantly better compared to unplanted controls, with hydrocarbon concentrations reduced to approximately 4 500 mg/kg, 49%. Hydrocarbon concentrations in unplanted control soil were reduced by 45% through natural biodegradation processes. Plant root and shoot tissue was periodically assessed for hydrocarbon accumulation and was shown to be negligible. A multispecies planted trial using C. ambiguus plus B. decumbens had no additional influence on total TPH removal. The final TPH removal efficiency in the multispecies trial was not significantly different p > 0.05 from that of the best single species performer of the two i.e. C. ambiguus. In a field application the planting of multiple species may still be desirable in order to preserve site biodiversity and assist rehabilitation of the area. A strong relationship between abundance of hydrocarbon degrading microorganisms in the rhizosphere and hydrocarbon biodegradation was demonstrated for all species p < 0.01. Those species which showed greatest stimulation of the microbial population resulted in enhanced TPH removal from soil. These species were the summer grass C. ambiguus and the winter species M. stipoides. This may allow for broader application both seasonally and geographically across Australia. B. decumbens showed successful rhizoremediation to a lesser degree, but may still be an option in multiple planting strategies. This investigation identified three Australian grass species from the nine evaluated that are candidates for further investigation for in situ rhizoremediation potential at field scale.

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Thacker, Gary W., and Jerry R. Cox. "Revegetation of Retired Farmland: Evaluation of Eight Range Grasses." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/201342.

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In July of 1988, we planted eight range grass species on retired farmland in the Avra Valley west of Tucson. In November of 1989, Arabian yellow bluestem, kleingrass, buffelgrass, "Catalina" lovegrass, and bermudagrass all yielded over 1000 Kg /Ha of oven dry forage "Cochise" lovegrass yielded 889 Kg /Ha, sideoats grama grass yielded 126 Kg /Ha, and bottlebrush yielded 86 Kg /Ha.

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48

Sylla, Diaguely 1951. "EFFECT OF MICROPHYTIC CRUST ON EMERGENCE OF RANGE GRASSES." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276554.

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Field and greenhouse studies were conducted in 1986 and 1987 to determine the impact of disturbance of microphytic soil crust on emergence of two warm season grass species. In the greenhouse, emergence of seedlings sown on the top of undisturbed crust, under the crust, on disturbed crust, and on bare soil was studied. The mean number of seedlings of "Cochise" lovegrass (Eragrostis lehmanniana x Eragrostis tricophora) and Kleingrass (Panicum coloratum) was higher on disturbed field plots than undisturbed plots. Disturbance reduced the microphytic crust cover, and the crust did not recover throughout the growing season. Presence of seedlings in samples of litter washed off the plots and observation on ants showed that all the seeds sown did not remain on the plots during the growing season. In greenhouse flats the emergence of seedlings of both species was greater on disturbed microphytic crust and bare soil than when seeded on top of or under an intact crust. Undisturbed crust restricted penetration of roots and shoots when seeds were placed on or under the crust.

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Smith, David James. "Nitrogen and phosphorus dynamics of roots of perennial grasses." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334247.

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Metcalfe, J. C. "Physiological responses of three agricultural grasses to water deficit." Thesis, Lancaster University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381781.

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