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Puterbaugh, Mary Norris. "Alpine plant-ant interactions /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841329.
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Edwards, David P. "Mutualism and cheating in a Peruvian ant-plant symbiosis." Thesis, University of East Anglia, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423805.
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Fonseca, Carlos Roberto Soerensen Dutra da. "Evolutionary ecology of Amazonian ant-myrmecophyte mutualisms." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296899.
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Shang, Jin. "Ant colony heuristics for the dynamic facility layout problem." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2579.
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Thesis (M.S.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains vii, 76 p. : ill. Includes abstract. Includes bibliographical references (p. 72-76).
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Chomicki, Guillaume [Verfasser], and Susanne [Akademischer Betreuer] Renner. "Ant/plant symbioses : evolution, specialization and breakdown / Guillaume Chomicki ; Betreuer: Susanne Renner." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2016. http://d-nb.info/1117474127/34.
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Baylis, Mathew. "The role of nutrition in an ant - lycaenid - host plant interaction." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235992.
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Fitzpatrick, Ginny M. "Thermal Ecology of Mutualism: The Consequences of Temperature for Ant-Plant Interactions." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/321375.
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Mutualism is an often-complex positive interaction between species, each of which responds independently to varying biotic and abiotic conditions. Temperature is an important factor that can affect species both directly (e.g., physiologically) and indirectly (e.g., via its effects on interactions with consumers, competitors, and mutualists). Although much research has investigated the consequences of temperature for individual organisms, the effects of temperature on the formation, dissolution, and success of species interactions remain minimally understood. The unique ways in which species respond to temperature likely play a role in structuring communities. Environmental heterogeneity, including the thermal environment, can promote coexistence when species exploit resources in different ways, such as by occupying different thermal niches. This dissertation examines the consequences of temperature for participants in an ant-plant protection mutualism, and investigates how the thermal ecology of individual species affects the interaction. Many mutualisms involve multiple species, or interacting guilds. In these mutualisms, species interact with partner species that vary in multiple characteristics. Mutualists are quite sensitive to both partner quantity and partner quality (e.g., their effectiveness at performing a beneficial task). Mutualisms between ants and plants are common across a variety of habitats worldwide, which differ in thermal range, fluctuation, and seasonality. In light of ants’ well-studied and predictable responses to temperature, ant-plant interaction networks provide excellent systems for studying the thermal ecology of mutualisms. In ant-plant protection mutualisms, each of the participants (ants, plants, and enemies) likely differs in its response to temperature. In addition to the direct effects of temperature on ant species, temperature may affect the magnitude of mutualistic interactions among species by affecting the quantity and quality of the reward offered to partners, and the activity of the partners themselves and the plant’s enemies (i.e., herbivores). If herbivores are more thermally tolerant than the mutualistic ant defenders, the consequences for plants may well be severe; however, if herbivores are less thermally tolerant than are the ants, the effects of rising temperatures might be mitigated: although less-effective ants might be more frequent in a warmer world, herbivores would be less abundant there. This dissertation describes the thermal ecology of the participants in a mutualism between the cactus Ferocactus wislizeni and four of its common ant defenders (Forelius pruinosus, Crematogaster opuntiae, Solenopsis aurea, and Solenopsis xyloni) in the extreme environment of the Sonoran Desert, USA. The ants are attracted to extrafloral nectar produced by the plant, and in exchange protect the plants from herbivores, including a common phytophagous cactus bug, Narnia pallidicornis (Hemiptera: Coreidae). Specifically, it investigates how thermal ecology of the individual species affects the interactions among those species. Also, it considers the impact of a tradeoff between behavioral dominance and thermal tolerance among ants.
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Tepe, Eric J. "Phylogeny, morphology, and the evolution of ant-plant associations in Piper section Macrostachys (Pipereceae)." Oxford, Ohio : Miami University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1133534289.
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Hill, JoVonn G. "ENVIRONMENTAL VARIABLES AFFECTING ANT (FORMICIDAE) COMMUNITY COMPOSITION IN MISSISSIPPI?S BLACK BELT AND FLATWOODS REGIONS." MSSTATE, 2006. http://sun.library.msstate.edu/ETD-db/theses/available/etd-04192006-141353/.
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The relationship of ant community composition to various habitat characteristics is compared across four habitat types and 12 environmental variables in Mississippi. The four habitat types include pasture, prairie, and oak-hickory forests in the Black Belt and forests in the Flatwoods physiographic region. Ants were sampled using pitfall traps, litter sampling, baiting and hand collecting. A total of 20,916 ants representing 68 species were collected. NMS and ANCOVA both revealed three distinct ant communities (pasture, prairie, and ?forests?) based on species composition and mean ant abundance per habitat type between the four habitat types. Principal component analysis (PCA) partitioned the 12 environmental variation into four axes with eigenvalues >1. Axis 1 differentiated open grass-dominated habitats from woodlands. In contrast axis two mainly separated pastures from prairie remnants. Multiple regression models using the four significant PCA axes revealed that total species richness was significantly affected by variation in the first two PCA axes. Forested sites supported approximately nine more species of ants than prairies and 21 more than pastures. Comparisons of the abundance of ant functional groups were also made between the four habitat types with multiple regression models to investigate how the environmental variables affected certain groups of ants. Annotated notes are included for each ant species encountered during this study.
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Ballantyne, Gavin. "Ants as flower visitors : floral ant-repellence and the impact of ant scent-marks on pollinator behaviour." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2535.
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As flower visitors, ants rarely benefit a plant, commonly disrupting pollination by deterring other flower visitors, or stealing nectar. This thesis examines three aspects of ant-flower interactions, focusing on the occurrence of floral traits that prevent disruption of pollination and a novel means by which ants may influence pollinator behaviour. To assess which types of plant species possess ant-repelling floral traits I carried out a survey of 49 Neotropical plant species. Around a third of these species were repellent to the common generalist ant Camponotus novograndensis (Formicinae). This repellence was positively correlated with large nectar volumes within individual flowers. It appears that there has been selection for floral ant-repellence as a defence against ant thieves in plant species that invest in large volumes of nectar. In some cases these repellent traits were effective against a wide range of ant species. However, in no plant species were predacious ants particularly repelled, indicating that there may be little selective pressure on non-ant-plants to defend potential pollinators from aggressive ants. To investigate the importance of coevolution in determining the effectiveness of ant-repellents, a small but diverse range of Mediterranean plant species were tested with the invasive nectar thieving ant Linepithema humile (Dolichoderinae) and the native but non-nectar thieving ant Messor bouvieri (Myrmecinae). Responses of both ant species to floral traits were very similar. The ability of some plants to restrict access to ant species with which they have no evolutionary history may help to reduce the impact invasive species, as nectar thieves, have on plant-pollinator interactions. It is reported that flowers recently visited by bees and hoverflies may be rejected for a period of time by subsequent bee visitors through the detection of scent-marks. Nectar-thieving ants could potentially influence the foraging decisions of bees in a similar way if they come to associate ant trail pheromones or footprint hydrocarbons with poor reward levels. However, my empirical work found no differences were found in bee visitation behaviour between flowers of Digitalis pupurea (Plantaginaceae), Bupleurum fruticosum (Apiaceae) or Brassica juncea (Brassicaceae) that had been in contact with ants and control flowers. Ant-attendance at flowers of these species may not reduce reward levels sufficiently to make it worthwhile for bees to incorporate ant scent-marks into foraging decisions. Investigations like these into the interactions between ants, flowers and other flower visitors are essential if we hope to understand the part ants play in pollination ecology, and determine how ants have helped shape floral evolution.
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Torres, Jiménez María Fernanda. "Effects of Andean geographic dynamics on the population history of Tococa-associated Azteca ants." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33066.
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Myrmecophytic plant species form associations where the ant colony inhabits structures in the plant and offers protection against herbivory in exchange for food and shelter. Widely distributed across the tropics, myrmecophytic mutualisms are particularly diverse in the Neotropics, a region characterized by the rapid and recent uplift of the Andean mountain range. It has been suggested that the abrupt change in terrain triggered the emergence of new niches, new barriers to gene ow and speciation. Studying ant-plant associations in the Neotropics not only provides insight into how associations evolve in time but also the impact that external factors, such as geographic changes, have in the evolution of mutualisms. Because of its wide distribution on both sides of the Andes, The Tococa guianensis- Azteca system is useful to explore the effects the Andean uplift had on the evolution of mutualisms. This thesis aims to 1. Identify the ants associating with T. guianensis and the lineages of ants and plants involved in the mutualisms in different populations on both sides of the Andes, 2. generate genomic data for both ants and plants to increase sampling of loci, and 3. estimate and calibrate the species trees to compare patterns of phylogenetics and temporal congruence between ants, plants and the Andean uplift. Most ant-plant studies focus on only one partner or study both partners by using already collected data for one of them. This project is the first study inferring the evolutionary history of both partners associated at that point in time and across a large area. This thesis identifies two main Azteca lineages associated with T. guianensis, each one distributed on different sides of the Andes. It addresses the monophyly of T. guianensis (and related species) and why such monophyly cannot be confirmed. Results show how both plants and ants were geographically structured congruent with timing of a split of populations coinciding with the Andean uplift. Moreover, four plants and fifteen ant genomes were assembled and used to estimate gene and species trees. For Tococa, candidate markers were selected for future resolution of the plant's phylogeny. Different histories but similar divergence times between ants and plants suggest that the mutualism has evolved in response to geographic changes rather than through codiversication, but that the mutualism persists thanks to the availability of the host. The information generated during this study provides the basis to understand the evolution of mutualisms, the genomic features of ants and plants and opens the possibility for Tococa and Azteca to become a model system.
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Schoeman, Colin Stefan. "Synergistic impact of invasive alien plants and the alien Argentine ant on local ant assemblages in the Western Cape." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/21759.
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Thesis (MSc)--Stellenbosch University, 2008.ENGLISH ABSTRACT: Alien trees, Pinus spp. and Eucalyptus spp., affect ants negatively in the Cape Floristic Region (CFR), a global biodiversity hotspot in South Africa. They reduce ant abundance and species richness, thus also changing ant assemblage structure. This is alarming, because almost 1300 species of plant species in the CFR are dispersed by certain indigenous ants, and thus there is concern for an indirect effect on indigenous plant assemblages. One of the most impacting ant species on seed dispersal is the invasive Argentine ant (Linepithema humile (Mayr)), which discards seeds outside its nest, where they do not germinate. Ten sites, on Vergelegen Wine Estate, were selected to explore these effects of alien plants. These varied from invaded to non-invaded sites. Each site consisted of six sampling points, which in turn consisted of four pitfall traps left out for seven days, during December 2005, February 2006, May 2006 and September 2006. Forty species of ant were sampled, and various analyses used to illustrate the comparative effects of plant invasion. All analytical methods showed that invasive alien plants had a significant impact on the abundance and richness of the ant species assemblage, by creating a dense canopy cover that changed the abiotic environment of the epigaeic ants’ habitat. Furthermore, increased alien tree invasion correlated significantly with Argentine ant abundances. The Argentine ant displaced Pheidole capensis and Camponotus spp., while it decreased the abundances of commonly-occurring indigenous ants, such as Lepisiota capensis and Plagiolepis spp. Displacement by the Argentine ant may be a result of indirect competition for food resources. The effects of invasive aliens are synergistic in that there is a cascade effects from initial plant invasions to subsequent animal invasion.
AFRIKAANSE OPSOMMING: Indringer bome, Pinus en Eucalyptus, affekteer miere op negatiewe wyse in die Kaap Florsitiese Streek (KFR), ‘n area in Suid Afrika van belang t.o.v. globale biodiversiteit. Hierdie uitheemse indringer bome verminder hulle hoeveelheid en spesies rykheid. Die bogenoemde is kommerwekkend omdat meer as 1300 plant spesies in the KFR versprei word deur miere. Die verandering in hoeveelheid en versameling van inheemse miere kan dus ernstige implikasies hê op die saad verspreiding van inheemse plant spesies. Een van die mees verwoestende effekte op saad verspreiding is veroorsaak deur die indringer Argentynse mier (Linepithema humile (Mayr)), wat sade neer werp buite hulle neste, waar hulle nie suksesvol kan ontkiem nie. Tien monsterings-tereine was geselekteer om die bogenoemde effekte te ondersoek op Vergelegen Landgoed. Hierdie het afgewissel van indringer tot skoon tereine. Elke terrein is op ses versamelings-plekke gemonster, met vier pitvalle, wat oopgelê het vir sewe dae gedurende Desember 2005, Februarie 2006, Mei 2006 en September 2006. 40 spesies van miere was gemonster. Indringer plante het ‚n betekenisvolle impak gehad het op die hoeveelheid en rykheid van die mier gemeenskappe, deur die skepping van ‚n dig baldakyn wat die abiotiese omgewing van die miere se habitat verander het. Die vermeerdering van indringer plante veroorsaak die vermeerdering van Argentyne miere. Kanonieke Mede-Respons Analise illustreer dat die Argentynse mier Pheidole capensis en Camponotus spp. verplaas het, terwyl dit ander inheemse mier getalle verminder het, soos Lepisiota capensis en Plagiolepis spp. Die verplasing deur die Argentynse mier mag die resultaat wees van indirekte wedywering vir hulpbronne. Die effekte van indringer species is dus sinergisties deur dat ‚n kaskade effek ontstaan vanaf plant tot dier indringer spesies.
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Shimizu, Kaya. "Host plant use in the assemblage of herbivorous insects on Macaranga myrmecophytes." Kyoto University, 2014. http://hdl.handle.net/2433/188797.
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Kyoto University (京都大学)0048
新制・課程博士
博士(人間・環境学)
甲第18359号
人博第672号
新制||人||162(附属図書館)
25||人博||672(吉田南総合図書館)
31217
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)教授 市岡 孝朗, 教授 加藤 眞, 教授 松井 正文
学位規則第4条第1項該当
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Yamasaki, Eri. "Evolutionary relationships between pollination and protective mutualisms in the genus Macaranga (Euphorbiaceae)." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188524.
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Handa, Chihiro. "Ecological studies on coccids inhabiting nests of the plant-ants on Macaranga myrmecophytes." Kyoto University, 2015. http://hdl.handle.net/2433/199394.
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Kyoto University (京都大学)0048
新制・課程博士
博士(人間・環境学)
甲第19070号
人博第723号
新制||人||173(附属図書館)
26||人博||723(吉田南総合図書館)
32021
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)教授 市岡 孝朗, 教授 加藤 眞, 教授 瀬戸口 浩彰
学位規則第4条第1項該当
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Nasseri, Nabil. "Investigating The Effects Of Ant-Hemipteran Mutualisms On The Invertebrate Community Structure And Their Host Plant, Honey Mesquite (prosopis Glandulosa)." ScholarWorks @ UVM, 2018. https://scholarworks.uvm.edu/graddis/971.
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Ants are ubiquitous in most communities and many form opportunistic mutualisms with honeydew-producing hemipterans (e.g. treehoppers). Hemipterans excrete honeydew, a carbohydrate rich substance, that ants harvest and, in return, ants protect their honeydew-producing partners from parasitoids, predators, and competitors. Given the efficacy of tending ants in removing hemipteran antagonists, and the strong roles that ants play within their communities as predators, competitors, and seed dispersers, surprisingly little is known of the effects of ant-hemipteran mutualisms (AHM) on the invertebrate communities in which they are embedded or on the plants that host AHM. Using observational and manipulative field experiments, I examined the long-term effect of AHM on their host plant’s, honey mesquite (Prosopis glandulosa), reproductive potential and quality. In addition, I measured how the presence of AHM affects the abundance, richness, diversity, and composition of the invertebrate communities living on honey mesquite.
Plants hosting AHM may indirectly benefit (through the removal of herbivore arthropods) or suffer (through the loss pollinators) due to the defensive behavior of tending ants. To determine the effects of AHM on their host plant, I established a four-year press experiment in which I removed AHM from 50 randomly trees, while leaving 50 as controls. In addition, I marked and followed 30 trees from which AHM were naturally absent. To assess if mesquite quality differed between trees hosting AHM and trees in which AHM were naturally absent, in 2012 I assayed foliar condensed tannin concentrations, a secondary defense compound, and, in 2015, I measured foliar nitrogen, phosphorous, potassium, magnesium, and iron as they are essential for growth and reproduction. I compared the reproductive potential between AHM present and removed trees by counting flowers and fruits across all 4 years of the study. Mesquite that hosted AHM contained significantly less condensed tannins and significantly higher concentrations of N%, Mg, and Fe. Furthermore, over the duration of the study mesquite hosting AHM contained significantly more flowers than those from which AHM were removed or naturally absent. My results indicate that AHM select trees of high quality and their continued presence is associated with high levels of reproductive potential.
Most studies that have evaluated community-level effects of AHM compare total abundance and species richness in communities (or host plants) with and without AHMs. However, both measures are dependent on sampling effort, complicating comparisons across different studies. To examine the effects of AMH on the arthropod community in mesquite, I first compared family richness and alpha diversity using standardized rarefaction and extrapolation curves. I then measured beta diversity and turnover in community composition from one year to the next. The removal of AHM increased invertebrate diversity and significantly altered community composition. Although treatments did not statistically differ in turnover rates, replacements occurred among treatments at the family level which may be biologically meaningful. Furthermore, herbivore and predator populations increased, and pollinator populations decreased following the removal of AHM. These results suggest that the presence of AHM can alter the composition of arthropod communities and food-web dynamics. However, these effects were significant in some years and not others, suggesting the importance of temporal variation in drivers of communities. Overall, my work demonstrates that AHM can be drivers of community composition and illustrate the importance of examining their effects across multiple seasons.
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Gonthier, David Jonathan. "Influence of Soil-Quality on Coffee-Plant Quality and a Complex Tropical Insect Food Web." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1271380868.
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Zhao, Qiao. "Conception and optimization of supercritical CO2 Brayton cycles for coal-fired power plant application." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0080/document.
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L'amélioration des systèmes énergétiques est considérée comme un levier technologique pour répondre aux défis liés à la croissance de la demande d’électricité et des émissions des gaz à effet de serre. Les futures centrales devraient présenter une intégration thermique plus flexible et des sources de chaleur mixtes possibles. Une des solutions fiables consiste à utiliser un cycle de Brayton au CO2 supercritique (CO2-SC), un tel cycle à haut rendement est théoriquement prometteur pour les applications nucléaires, fossiles et solaires thermiques. Un des principaux obstacles au déploiement du cycle de Brayton au CO2-SC est de justifier sa faisabilité, sa viabilité et son potentiel à l’échelle industrielle. Dans ce contexte deux axes de recherche ont été identifiées : • Une sélection rigoureuse de l’équation d’état qui permet de représenter les propriétés d’intérêt du CO2-SC. • Une nouvelle méthodologie pour l’optimisation des centrales électriques, permettant de sélectionner automatiquement le procédé optimal parmi une grande quantité de configurations possibles (dénomme superstructure). Les résultats de la première partie de cette thèse mettent en lumière que l’équation de SW est pertinente pour limiter l’impact de l’imprécision de l’équation d’état sur le dimensionnement du procédé. Dans cette thèse, un simulateur de procédé commercial, ProSimPlus a été combiné avec un solveur type évolutionnaire (MIDACO) afin d’effectuer des optimisations superstructure. Premièrement, le critère d’optimisation est de maximiser le rendement énergétique du procédé. Dans un deuxième temps, on cherche simultanément à minimiser les coûts du procédé. Pour ce faire, des fonctions de coût internes à EDF ont été utilisées afin de permettre l’estimation des coûts d'investissement (CAPEX), des dépenses opérationnelles (OPEX) et du coût actualisé de l'électricité (LCOE)Efficiency enhancement in power plant can be seen as a key lever in front of increasing energy demand. Nowadays, both the attention and the emphasis are directed to reliable alternatives, i.e., enhancing the energy conversion systems. The supercritical CO2 (SC-CO2) Brayton cycle has recently emerged as a promising solution for high efficiency power production in nuclear, fossil-thermal and solar-thermal applications. Currently, studies on such a thermodynamic power cycle are directed towards the demonstration of its reliability and viability before the possible building of an industrial-scale unit. The objectives of this PhD can be divided in two main parts: • A rigorous selection procedure of an equation of state (EoS) for SC-CO2 which permits to assess influences of thermodynamic model on the performance and design of a SC-CO2 Brayton cycle. • A framework of optimization-based synthesis of energy systems which enables optimizing both system structure and the process parameters. The performed investigations demonstrate that the Span-Wagner EoS is recommended for evaluating the performances of a SC-CO2 Brayton cycle in order to avoid inaccurate predictions in terms of equipment sizing and optimization. By combining a commercial process simulator and an evolutionary algorithm (MIDACO), this dissertation has identified a global feasible optimum design –or at least competitive solutions– for a given process superstructure under different industrial constraints. The carried out optimization firstly base on cycle energy aspects, but the decision making for practical systems necessitates techno-economic optimizations. The establishment of associated techno-economic cost functions in the last part of this dissertation enables to assess the levelized cost of electricity (LCOE). The carried out multi-objective optimization reflects the trade-off between economic and energy criteria, but also reveal the potential of this technology in economic performance
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Costa, Fernanda V., Marco A. R. Mello, Judith L. Bronstein, Tadeu J. Guerra, Renata L. Muylaert, Alice C. Leite, and Frederico S. Neves. "Few Ant Species Play a Central Role Linking Different Plant Resources in a Network in Rupestrian Grasslands." PUBLIC LIBRARY SCIENCE, 2016. http://hdl.handle.net/10150/622488.
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Ant-plant associations are an outstanding model to study the entangled ecological interactions that structure communities. However, most studies of plant-animal networks focus on only one type of resource that mediates these interactions (e.g, nectar or fruits), leading to a biased understanding of community structure. New approaches, however, have made possible to study several interaction types simultaneously through multilayer networks models. Here, we use this approach to ask whether the structural patterns described to date for ant plant networks hold when multiple interactions with plant-derived food rewards are considered. We tested whether networks characterized by different resource types differ in specialization and resource partitioning among ants, and whether the identity of the core ant species is similar among resource types. We monitored ant interactions with extrafloral nectaries, flowers, and fruits, as well as trophobiont hemipterans feeding on plants, for one year, in seven rupestrian grassland (campo rupestre) sites in southeastern Brazil. We found a highly tangled ant-plant network in which plants offering different resource types are connected by a few central ant species. The multilayer network had low modularity and specialization, but ant specialization and niche overlap differed according to the type of resource used. Beyond detecting structural differences across networks, our study demonstrates empirically that the core of most central ant species is similar across them. We suggest that foraging strategies of ant species, such as massive recruitment, may determine specialization and resource partitioning in ant-plant interactions. As this core of ant species is involved in multiple ecosystem functions, it may drive the diversity and evolution of the entire campo rupestre community.
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Jones, Ian M. "The Ecology of Extrafloral Nectar in Senna mexicana var. chapmanii." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2594.
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Extrafloral nectar (EFN) mediates food-for-protection mutualisms between plants and defensive insects. Senna mexicana var. chapmanii is a perennial legume native to the pine rockland habitats of south Florida. My dissertation focuses on how anthropogenic changes to the pine rocklands might affect EFN production by S. chapmanii, and the outcome of EFN mediated interactions. First, I investigated the influence of time of day, leaf damage, and leaf age on EFN production in S. chapmanii. Plants produced more nectar at night than during the day, and leaf damage resulted in increased EFN production. Furthermore, the response to leaf damage was greater when plants were damaged in the morning than when plants were damaged at night. Damage to young leaves elicited a stronger defensive response than damage to older leaves, in line with optimal defense theory. Second, I conducted a field experiment to determine the effects of ant activity, and light intensity, on herbivory rates, growth, and reproductive fitness in S. chapmanii. In shaded habitats, the presence of ants had no effect on herbivory rates, seed set, or plant size. In sunny habitats, however, plants with ants suffered less herbivore damage, produced more seeds, and grew larger over the duration of the one year study. Third, through a controlled greenhouse experiment I examined the effects of light intensity, and red/far-red light ratios, on EFN production in S. chapmanii. Plants in light-limited conditions produced less EFN, and leaf damage elicited increased EFN production regardless of light conditions. Ratios of red/far-red light, however, did not affect EFN production in either damaged or undamaged plants. Finally, I conducted a field study to determine how ants affect reproductive fitness in S. chapmanii. Over a period of eight months I observed the effects of ants on the activity of herbivores, predators, pollinators, and pre-dispersal seed predators. Relative pollinator efficiency, and rates of pre-dispersal seed predation, were unaffected by ants. Plants with ants, however, were quicker to establish, grew larger, and produced floral displays that attracted more pollinators. In S. chapmanii ants affected plant reproductive fitness simply by facilitating growth and establishment, with coincidental effects on reproductive investment.
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Nicolai, Nancy Carol. "Plant community dynamics governed by red harvester ant (Pogonomyrmex barbatus) activities and their role as drought refugia in a semi-arid savanna." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2657.
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This study examined modifications made by Pogonomyrmex barbatus, by their
processes of granivory and nest construction, to forb and grass dynamics under large-scale
disturbances of fire, recent drought and long-term, large-mammalian herbivory using
comparative studies, field experimental manipulations, and a simulation model on the
Edwards Plateau, Texas. Ant nests are refugia for grass survival during extreme droughts
as demonstrated during the drought of 1998 to 2002. Significantly greater cover of grasses
and lower abundance and cover of forbs was found beside nests compared with surrounding
habitat throughout the drought and recovery. Grasses near nests may be the seed source for
surrounding habitats during recovery.
Seeds were differentially collected among most forbs and grasses despite seed
abundance. Harvest was significantly reduced in the fall relative to spring. During
preference experiments, harvest differences were found between grazing treatments for two
of four species, but only during the spring. High lipid content seeds were unpreferred in fall
compared to high protein and carbohydrate content seeds.
Granivory influences on seedling establishment were studied by comparing seedling
recruitment among sown and naturally occurring seeds excluded and open to foragers.
Exclosures were placed in three nest densities and two burn treatments. Seeds in exclosures
produced significantly more seedlings than open arenas only during the first year of drought
recovery. Densities of grasses and annual forbs were higher in open arenas the second year due to indirect effects of granivory. By reducing seeds ants release seedlings from
competition. Sown seedling abundance was unaffected by colony density and fire.
Colony density and distribution were influenced by topography, soil types, soil depth
and woody cover, but not by historical grazing treatments. Cleared vegetation on nest disks
impacted less than 1% of total surface area and losses were compensated by greater basal
cover of grasses next to disks compared to surrounding habitats. Foraging areas influenced
17.3-73.6% of surface area and could diminish seed populations for potential seedlings.
Model results agree with experimental observations that communities may be
modified by P. barbatus presence due to differential responses of grass species to interaction
between nests or granivory and rainfall amounts.
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Marques, Edward. "Effects of the Exotic Red Imported Fire Ant (Solenopsis invicta) on the Growth and Survival of the Threatened Hooded Pitcher Plant (Sarracenia minor)." UNF Digital Commons, 2015. http://digitalcommons.unf.edu/etd/615.
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Plants and insects are some of the most biodiverse groups in the world and are constantly interacting. One unique interaction that has been observed occurs between carnivorous plants and insects; some plant species are capable of capturing and digesting insects for nutrients. Despite preying on these insects, there are cases where such interactions can been viewed as mutualistic. For instance, a nectar reward is produced by the plant to attract insects, and during visitation insects may fall prey to these plants. Additionally, carnivorous myrmecophytic plants may receive an added indirect benefit in the form of reduced herbivory, since ants have the ability to indirectly protect and drive off herbivores from the plant. However, this type of indirect defensive benefit has been rarely observed in carnivorous plants. To determine the nature of the relationship between carnivorous plants and ants, a predator-exclusion experiment was performed in situ using a natural population of the hooded pitcher plant, Sarracenia minor. The presence of the red imported fire ant, Solenopsis invicta, was manipulated in the pitcher plant population to determine if the presence of this non-native ant affects the survival and growth of this carnivorous pitcher plant. From June-November 2014 mean pitcher height and width, number of pitchers, and proportion of pitchers with herbivory present was recorded monthly. Results indicated that pitcher width (p = .042) and the number of pitchers (p = .038) was significantly lower when the presence of S. invicta was reduced. Specifically, the limited presence of S. invicta led to a 21% reduction in mean number of pitchers and a 2.2% reduction in mean pitcher width. This indicated that this non-native ant does provide a direct nutritional benefit for the plant. However, the presence of the ant had no effect on pitcher height and the proportion of pitchers with herbivory present. But, when the proportion of pitchers with herbivory present was compared to a previous native ant study, herbivory proportions where similar or lower when taking the number of ants present into account. This suggests that this non-native ant and native ants equally provide defensive benefits for this native threatened species. Overall, this studied illustrated that carnivorous plants may exhibit similar multiple benefits from a single interaction with a non-native insect that is both prey and provides defense against herbivores.
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Tarrant, Valerie M., and valerie tarrant@deakin edu au. "Melbourne's indigenous plants movement: The return of the natives." Deakin University. School of History, Heritage and Society, 2005. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20061207.113857.
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This thesis examines Greater Melbournes indigenous plants movement from the 1930s to the early twenty first century. It demonstrates the important scientific and educational role of the public intellectual, Professor John Turner, and of the Melbourne University Botany School which he led for thirty five years. The case study of the movement within the City of Sandringham and its successor the City of Bayside reveals how the inhabitants of an urbanised are responded to threats to the indigenous trees and wildflowers of their neighbourhood, stimulating botanists to assist them and using political means in order to achieve their conservation objectives. The thesis draws upon a range of local archives, conservation literature and private papers.
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Santos, Iracenir Andrade dos. "Características estruturais de plantas determinam riqueza de espécies de formigas no Cerrado?" Universidade Federal de Viçosa, 2006. http://locus.ufv.br/handle/123456789/3949.
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Previous issue date: 2006-02-22Conselho Nacional de Desenvolvimento Científico e Tecnológico
Species diversity is affected by some processes that operate in several spatial scales. In local scale the biological and physical interactions are extremely important for the process of diversity determination. The aim of this study was investigate whether structural characteristics of trees, such as crown architecture, bark rugosity and size of the plant, influence ant species diversity, testing the following hypotheses: 1) plants with higher bark rugosity have more ant species; 2) plants with thicker suber have more ant species; 3) plants with higher crown architecture have more ant species; and 4) larger plants have more ant species. The sampling was carried out with the use of pitfall traps in 120 plants, in four plots of Cerrado, in the FLONA of Paraopeba, Minas Gerais, Brazil. We sampled 73 ant species in 46 tree species. Ant species richness decreased with bark rugosity.Suber thickness, crown architecture, and plant size did not influence ant richness species in this cerrado area. We observed that the evaluation of local factors in very small spatial scales, such as plant structure, growth form, size and plots in which the plants are inserted, are fundamental to understand ant species richness in Cerrado. In this way, we suggest that the processes in small scales, such as structural characteristics and plant species, as well as resources, may be determinant factors of ant richness species in Cerrado environments.
A diversidade de espécies é afetada por vários processos que operam em diversas escalas espaciais. Em escala local, as interações biológicas e físicas são geralmente importantes para a determinação da diversidade, e neste aspecto as interações entre formigas e plantas são bastante estudadas. Este estudo teve como objetivo principal investigar a importância de características estruturais das árvores, tais como arquitetura de copa, rugosidade de cascas e tamanho da planta, no padrão de ocorrência das comunidades de formigas arborícolas em cerrado, testando as seguintes hipóteses: 1) plantas com cascas mais rugosas têm maior riqueza de espécies de formigas; 2) plantas com súber mais espesso têm maior riqueza de espécies de formigas; 3) plantas com arquitetura de copas mais complexas têm maior riqueza de espécies de formigas; e 4) plantas maiores têm mais espécies de formigas. As coletas foram feitas com armadilhas do tipo pitfall em 120 plantas, distribuídas em quatro parcelas, no Cerrado da FLONA de Paraopeba, Minas Gerais, Brasil. Foram coletadas 73 espécies de formigas em 46 espécies de árvores. A rugosidade de casca teve uma relação significativa e inversa à riqueza de espécies de formigas. Assim, plantas com cascas mais rugosas apresentaram menor riqueza de espécies de formigas. Já a espessura do súber, a arquitetura de copa e o tamanho das plantas não foram significativos na riqueza de espécies de formigas nesta área de cerrado. Observamos que a avaliação de fatores locais em escalas muito pequenas, como estruturas das plantas, forma de crescimento, tamanho e as parcelas nas quais as plantas estão inseridas, são fundamentais para a compreensão do padrão de riqueza e distribuição das espécies de formigas no cerrado. Desse modo, sugerimos que os processos em pequenas escalas, tais como características estruturais e espécies das plantas, bem como recursos, sejam considerados como fatores importantes na riqueza de espécies de formigas em ambientes de cerrado.
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au, A. Mccomb@murdoch edu, and Arthur James McComb. "Plants and the environment." Murdoch University, 2006. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20070828.135211.
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Ye, Zhengqian. "Effect of low temperature on boron nutrition of oilseed rape and sunflower." Murdoch University, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20060510.154332.
Full textAbstract:
Several reports appear in the literature linking low temperature damage in plants with boron (B) deficiency and alleviation of low temperature injury with B application has been reported in some crops and trees. These results imply that low temperature might increase plant B requirements, beside the reduction of B uptake by plant roots, or that low B tissues might be more sensitive to cold temperature damage than B adequate tissues. In controlled experiments, it has been shown that low root zone temperature (RZT) induces B deficiency in cassava, a tropical root crop. Apart from this, there are few definitive detailed investigations on low temperature effects on B nutrition of plants, including temperate species which are more tolerant of low temperature.
Winter oilseed rape (Brassica napus L.), a crop sensitive to low B supply, is a major crop in the middle and lower Yangtse river basin, China, where low B soils are widespread. Appearance of B deficiency in oilseed rape often coincides with cold weather during its winter and spring growth. However, the incidence and severity of B deficiency of oilseed rape plants and the efficacy of B fertilization varies from year to year and location to location in ways that are not explained simply by differences in cultivar, agronomy or soil B levels. Low temperature is probably one of the important environmental factors influencing growth and yield of oilseed rape in relation to B nutrition.
Therefore,the objective of the studies in this thesis was to investigate mechanisms of low temperature effects on B nutrition of plants with emphasis on oilseed rape. Field and glasshouse experiments were carried out and the physiological basis of plant response to B at different air and root temperatures is discussed.
A field experiment with oilseed rape cv. Zheyouyou 2 was carried out on a red soil (Hapludult, US Soil Taxonomy) with low B availability in Zhejiang province, China. Canopy covers made from transparent plastic sheets, which increased night temperatures by up to 1.5 oC around shoots for 15 days in early February, strongly increased shoot dry weight at all levels of B supply. Furthermore, covering plants increased shoot dry weight of B deficient plants without increasing their leaf B concentration. This suggests that internal B requirements were decreased by canopy covering, possibly due to higher temperatures within the canopy.
Experiments conducted to investigate the effect of RZT (10 and 20n oC) on oilseed rape cv. Hyola 42 response to B in solution culture, in summer and winter, showed that regardless of canopy conditions, low RZT (10 oC) promoted the distribution of shoot B towards the actively growing leaves, especially when B supply was low. At low B supply, B deficiency symptoms appeared later at 10 oC than 20 oC RZT and B concentrations in the youngest fully opened leaves (YOL) were higher in plants grown at RZT of 10 oC than that at 20 oC. Growth of plant dry weight (DW) was not affected
by RZT in the summer but was greatly reduced at 10 oC than 20 oC in winter. In B adequate plants, shoot to root ratio (S/R ratio) was not affected by RZT regardless of canopy conditions. By contrast, S/R ratio was smaller in low B plants at 10 oC than 20 oC. In addition, low RZT delayed occurrence of plant B deficiency symptoms regardless of plants¡¦ pre-treatment RZT (either 10 or 20 oC). These results appeared to contradict the response to low RZT found in previous studies with cassava.
In a subsequent experiment, low RZT of 5 oC not only greatly reduced plant DW production of oilseed rape, but also accentuated plant B deficiency. Partitioning of B into the young growing shoots was also depressed and a significant decrease of B concentration in the youngest shoot parts was caused by 5 oC RZT in comparison with that at the control RZT (10 oC). Similar results were also observed in sunflower (Helianthus annuus L. cv. Hysun 25). But B deficiency symptoms in sunflower were induced by RZT as high as 12 oC, when plants were supplied with 0.25 £gM B, whilst these plants were free from B deficiency at warmer RZT (17 - 27 oC). Higher external B concentrations were required at such RZT (Chilling temperature) for plant growth free from B deficiency. Therefore, there is a RZT threshold below which an increased response to B is expected in plants of oilseed rape and sunflower. And in the range of chilling RZT, the external B requirement for shoot growth increased with lower RZT. The threshold RZT was considerably higher in the chilling-sensitive plant species, sunflower, than in oilseed rape, a chilling-resistant plant species.
At chilling RZT, leaf functioning was impaired by low B supply as measured by potassium (K) leakage from the youngest mature leaf blade (YML) of sunflower, whereas it was much less directly affected by RZT, and there was no effect of RZT on B- adequate plants. By contrast to leaves, root function was impaired more by chilling RZT than low B.
Despite their different threshold RZT, in both oilseed rape and sunflower, the rates of B uptake (BUR) and B translocation from root to shoot (BTR) were dramatically depressed by chilling RZT especially at low B supply (0.2 £gM B): being only 30% of those at the control (5 oC vs 10 oC RZT) in oilseed rape and 33% (10 oC vs 20 oC RZT) in sunflower, respectively. By contrast, there was little or no difference over a range of warmer RZT (10 - 20 oC for oilseed rape, and 20 ¡V 27 oC for sunflower). It is predicted that higher rates of B application will be required for plant growth when soil temperature is below a critical threshold, which is between 5 and 10 oC for oilseed rape, and about 17 oC for sunflower, respectively. Below the threshold RZT plant B deficiency was induced and accentuated due to impairment of B translocation into growing shoot parts besides the decrease of B uptake rate and B transport rate and greater shoot to root ratio.
In comparison with RZT, little is known about causal mechanisms linking cold air temperature and B nutrition. Experiments in this thesis showed not only B transport to the shoot was strongly reduced by low night air temperature during a 6 day period (11.719.4 vs 15.5 ¡V 23.5 oC), but also that an overnight chilling (at 0 oC) could cause more severe injury to low B than adequate B leaves of oilseed rape plants, expressed by higher solute leakage, in comparison with control (at 10 oC). Moreover, after chilling treatment, solute leakage from low B leaves was increased by exposure to light, which suggests that low temperature injury to leaves in low B plants after a freezing night in the field is at least partly a consequence of light induced damage of leaves.
In summary, at chilling temperature, B uptake, transport and partitioning into growing shoots are strongly impaired, and B use efficiency in the growing tissues might be reduced as well. Low temperature contributes to plant B deficiency also by increasing S/R ratio, so that shoot B demand is not satisfied by available B. Furthermore, low air temperature might increase the internal B requirement for shoot growth. To further understand mechanisms of low temperature, especially the air temperature, effects on plant responses to B, more research is needed, such as the relationship between low temperature and B incorporation into cell walls which may play an important role in leaf tolerance to chilling temperature.
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Barros, Regiane Silva de 1986. "Despacho de um arranjo hidro-eólico incluso em um sistema coordenado centralmente : modelo híbrido de otimização com meta-heurísticas." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265765.
Full textAbstract:
Orientadores: Paulo de Barros Correia, Ieda Geriberto HidalgoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Este trabalho propõe um modelo de despacho ótimo no horizonte diário de operação, que permite coordenar a operação entre uma usina eólica e uma usina hidrelétrica. Nessa abordagem, a usina eólica é despachada em primeira instância. Para suprir eventuais saídas forçadas que possam ocorrer na geração eólica, aloca-se um valor de reserva girante incremental na usina hidrelétrica usando o conceito de Value at Risk como métrica de risco da geração eólica. O modelo é formulado como um problema multiobjetivo que busca maximizar a geração de energia e minimizar o número de partidas e paradas da usina hidrelétrica. O acoplamento hidráulico é considerado através da meta diária de defluência da usina. O problema é solucionado em duas etapas. A primeira resolve 24 problemas estáticos, que representam o despacho horário da usina hidrelétrica, separadamente. Essa etapa emprega o Algoritmo Genético para otimizar a operação da usina em termos da geração de energia elétrica. A segunda etapa soluciona o problema dinâmico, ou seja, o despacho diário da usina. A natureza do problema dinâmico, correspondendo à obtenção de caminhos mínimos eficientes em termos de partidas e paradas, sugeriu o uso da técnica de Otimização por Colônia de Formigas. As restrições de reserva girante, meta de defluência, atendimento do contrato de demanda e limites operacionais das usinas são plenamente satisfeitas. A diferença entre os montantes de energia produzidos e contratados é liquidada no mercado de curto prazo e valorada ao preço de liquidação das diferenças. O modelo se mostrou adequado em termos de tempo computacional e em relação à qualidade das soluções obtidas
Abstract: This work proposes an optimal dispatch model in the daily horizon, which coordinates the operation of a wind farm and a hydroelectric plant. In this approach the wind farm is dispatched first. In order to provide eventual faults that may occur in the wind farm generation, an incremental spinning reserve is allocated in the hydroelectric plant using the concept of Value at Risk. The model is formulated as a multiobjective problem which seeks to maximize the energy generation and to minimize the number of start-ups and shut-downs of the hydroelectric plant. The plant¿s hydraulic coupling is considered through the daily released flow goal. The model is solved in two stages, the first one solves, separately, 24 static problems that represents the hourly dispatch of the hydroelectric plant. This stage employs Genetic Algorithm to optimize the operation of the hydroelectric plant in terms of electric energy generation. The second stage considers the dynamic problem, which is the plant¿s daily dispatch. The nature of the dynamic problem, which implies in obtaining efficient shortest paths in terms of start-ups and shut-downs, suggests the use of the Ant Colony Optimization. The spinning reserve, the released flow goal, the demand contract and the generating unit¿s operational limits are fully satisfied. The difference between the energy amounts produced and contracted are liquidated in the spot market and it is valuated with the settlement differences price. Regarding computational costs and solutions quality, the model suitability is shown
Doutorado
Planejamento de Sistemas Energeticos
Doutora em Planejamento de Sistemas Energéticos
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Fuse(Kiyono), Mieko. "A study of the foraging behavior on ants by the utilization of plant-ant relationship in wild chimpanzees at the Mahale Mountains National Park, Tanzania." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/180375.
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Swarts, Nigel. "Integrated conservation of the rare and endangered terrestrial orchid Caladenia huegelii H.G. Reichb /." Connect to this title, 2007. http://theses.library.uwa.edu.au/adt-WU2008.0044.
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Vidal, Mayra Cadorin 1989. "A predação de formigas por Rhinoleucophenga sp. nov. (Diptera, Drosophilidae) e seus efeitos no mutualismo entre formigas e Qualea grandiflora (Vochysiaceae)." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316186.
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Orientadores: Paulo Sergio Moreira Carvalho de Oliveira, Sebastian Felipe Sendoya EcheverryDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Exploradores do mutualismo - indivíduos que utilizam recursos/serviços produzidos pelos mutualistas sem recompensá-lo - podem trazer sérios danos aos mutualistas explorados, principalmente quando acaba matando um dos parceiros mutualistas. Plantas portadoras de NEFs podem manter mutualismos com formigas visitantes, que defendem a planta contra insetos herbívoros. No cerrado de Itirapina (SP), encontramos larvas de uma nova espécie de díptero do gênero Rhinoleucophenga (Drosophilidae) que constroem abrigos de consistência pegajosa em cima dos NEFs de Q. grandiflora. Assim, larvas de Rhinoleucophenga podem interferir no mutualismo formiga-planta, agindo potencialmente como exploradora dessa interação. O presente estudo teve como objetivos principais investigar a história natural dessas larvas, principalmente aspectos do comportamento e interação com Qualea e formigas, e analisar seu possível efeito sobre o mutualismo formiga-Q.grandiflora. Durante observações de campo comprovamos que formigas e outros insetos visitantes dos NEFs podem ficar presos ao abrigo larval e servir de alimento para o díptero. Larvas de Rhinoleucophenga sp. nov. ocorrem em 85% dos indivíduos de Q. grandiflora, principalmente na época chuvosa ocupando preferencialmente nectários ativos, perto do ápice e na face abaxial dos ramos. No levantamento da mirmecofauna visitante de Q. grandiflora encontramos 27 morfoespécies de formigas, sendo as duas mais frequentes Camponotus crassus, e uma espécie do gênero Brachymyrmex, as mesmas que foram mais comumente encontradas presas aos abrigos das larvas mirmecófagas. Vimos que as larvas expõem uma substância líquida na abertura de seu abrigo, que comprovamos possuir composição química muito similar a do néctar extrafloral de Q. grandiflora, o que sugere que as larvas utilizam o néctar da própria planta para atrair suas presas. Na presença de larvas de Rhinoleucophenga, menos formigas visitam as plantas e também por menos tempo. Esse forrageamento diferenciado resultou em menor ataque de formigas a cupins vivos (herbívoros simulados). Além disso, na presença das larvas mirmecófagas houve maior abundância de herbívoros mastigadores e maior área foliar removida por herbívoros. Podemos afirmar que as larvas de Rhinoleucophenga sp. nov. utilizam o recurso da planta sem beneficiá-la. Além disso, as larvas do díptero também prejudicam a planta e suas formigas mutualísticas, uma vez que alimentando-se delas, aumentam a incidência de herbívoros e a herbivoria foliar na planta. Dessa forma, as larvas de Rhinoleucophenga sp. nov. estão agindo como exploradoras e do mutualismo formiga-Qualea grandiflora e predadoras de topo, causando efeito cascata nesse sistema
Abstract: Exploiters of mutualism - individuals that use resources/services offered by mutualists giving nothing in return - can cause serious damages to mutualists, especially when it involves the death of one of the partners. Plants bearing EFNs usually maintain mutualism with aggressive ants, which defend the plant against herbivores. In a cerrado area at Itirapina (SP), we found a new dipteran species of the genus Rhinoleucophenga (Drosophilidae) whose larvae construct sticky shelters on top of active EFNs of Q. grandiflora. Field observations revealed those ants and others insects that visit the EFNs can get trapped at the sticky larval shelters, and are consumed by the larvae. We hypothesized that Rhinoleucophenga larvae could be interfering with the ant-Qualea mutualism, and thus be acting as an exploiter of this interaction. Here, we investigate the natural history of Rhinoleucophenga larvae, mainly its behavior and association with ants and Qualea, and their possible effect on the ant-Qualea mutualism. Larvae of Rhinoleucophenga sp. nov. occur in 85% of the individuals of Qualea grandiflora inspected at Itirapina. Rhinoleucophenga larvae occur mostly during the rainy season, mainly at the apex and abaxial surface of the branches. We found 27 ant species visiting Qualea. The two most frequent visiting species, Brachymyrmex sp. 1 and Camponotus crassus, were most common insects trapped at larval shelters. Chemical analyses revealed that Rhinoleucophenga larvae use Qualea's extrafloral nectar to attract insect prey to their shelters. Qualea branches infested by ant-preying Rhinoleucophenga larvae had ant visitors for less time and in lower numbers than dipteran-free branches. This negative effect on ant foraging activity resulted in decreased levels of ant aggression to live termite-baits (i.e., simulated herbivores) on leaves of dipteran-infested compared to dipteran-free branches. Controlled field experiments demonstrated that branches hosting Rhinoleucophenga larvae had higher numbers of chewing herbivores and higher levels of foliar herbivory than dipteran-free branches. By using Qualea's EFNs as larval shelters and as attractants to ant prey, larvae of Rhinoleucophenga sp. nov. negatively affect both the plant and ant visitors, with cascading effects ultimately resulting in increased herbivore damage to leaves. Thus we can conclude that ant-eating Rhinoleucophenga larvae are acting as exploiters of the mutualism between ants and Q. grandiflora and also as top predator, causing cascade effect on this system
Mestrado
Ecologia
Mestra em Ecologia
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Pharmawati, Made, and mikewood@deakin edu au. "A study of the natriuretic peptide hormone system in plants." Deakin University. School of Biological and Chemical Sciences, 1999. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20060727.145040.
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In this study, both physiological and cellular effects are elicited by natriuretic peptides (NPs), a novel type of plant hormone. It was found that rat ANP (rANP) influenced stomatal opening movement in Tradescantia sp., where a significant increase in stomatal opening was observed in the presence of 1 µM rANP. Furthermore, this effect is mediated by cGMP, a (putative) second messenger of NPs. Two inhibitors of guanylyl cyclase, LY 83583 and methylene blue, inhibited rANP-induced stomatal opening. In contrast, stomatal opening is induced in a concentration dependent manner by the cell permeant cGMP analogue 8-Br-cGMP. In addition it was found, that like in animals, the secondary structure of rANP is essential for rANP responses. Linearised rANP is biologically inactive.
Since ANP elicit plant responses, an attempt was made to isolate NP analogues from plants. A protocol for partially purifying NP from plants was developed. It was found that two fractions eluted from an immunoaffinity chromatography column (0.5 M KCI eluted fraction and 0.75 M KCI eluted fraction) were biologically active.
The level of cGMP in response to NPs was also tested. It is suggested that the receptor of NP is specific since only 0.75 M KCI eluted fractions increased cGMP levels in Zea mays root stele tissue. rANP did not elicit an effect on cGMP levels in this tissue and LY 83583 did not affect this response. It is therefore argued that a plant specific biologically active NP system is present in the stele and it is predicted that NPs modulate solute movement in this tissue.
NPs also influence K+, Na+ and H+ fluxes in Zea mays root stele. Increase in both K+ and Na+ uptake were observed after 30 min., while H+ flux shifted immediately toward influx in the presence of both 0.5 and 0.75 KCI eluted fractions. Finally, a model is proposed for the effect of NPs on solute movement and its signalling system in plants.
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Winger, Alison Marie. "Impact of 4-hydroxy-2-nonenal in Arabidopsis mitochondria /." Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0121.
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Lee, Alex Chun Pong. "Dynamics of the plant mitochondrial proteome : towards the understanding of metabolic networks." University of Western Australia. School of Biomedical and Chemical Sciences, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0181.
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[Truncated abstract] The mitochondrion is the energy powerhouse that provide energy to many metabolic functions in the form of ATP. Mitochondria in plants are also known to carry out a variety of other important biochemical processes within the cell, including the anaplerotic function of tricarboxylic acid (TCA) cycle, one-carbon metabolism and portions of photorespiration. Dynamics of the mitochondrial proteome in plants underlies fundamental differences in the roles of these organelles under different developmental and environmental conditions. A quantitative comparative proteomic approach was carried out to analyze mitochondria isolated from non-photosynthetic models, cell culture and root, and compared them to mitochondria isolated from photosynthetic shoots. The glycinedependent respiration rate and the protein abundance of the photorespiratory apparatus was found to be higher in shoot than cell culture and root mitochondria. Also, there were major differences in the abundance and/or activities of enzymes in the TCA cycle between the three systems examined. The metabolic pathways that relied on the supply of intermediates from TCA cycle and photorespiration were also altered, namely cysteine, formate and one-carbon metabolism, as well as amino acid metabolism focused on 2-oxoglutarate generation, and branched-chain amino acids degradation. To further provide insight into the extent of mitochondrial heterogeneity in plants, mitochondria isolated from six organ/cell types, leaf, root, cell culture, flower, stem and silique were analyzed. Of the 251 protein spots on a 2D-gel of the mitochondrial soluble/matrix fraction, the abundance of 213 spots were significantly varied between different samples. Identification of these spots revealed a non-redundant set of 79 proteins which were differentially expressed between organ/cell types. ... Importantly, posttranslational modifications played a significant role in the dynamics of the leaf mitochondrial proteome during the diurnal cycle. Overall, these findings indicated that the mitochondrial proteome is dynamic in order to fulfil different functional and physiological requirements in response to organspecific growth and changes in the external environments. These results also indicated that the majority of the changes in the mitochondrial proteome occurred in the matrix and suggested differences in substrate choice/availability in various plant organs and during the diurnal cycle. Further, these analyses demonstrate that, while mitochondrial proteins are regulated transcriptionally by the nucleus, post-transcriptional regulation and/or post-translational modifications play a vital role in modulating the activation state and/or regulation of proteins in key biochemical pathways in plant mitochondria. The integration of proteomics data with respiratory measurements, enzyme assays and transcript datasets will allow the identification of organ-enhanced and/or light/darkresponsive metabolic pathways as well as providing potential targets for reverse genetic approaches for further functional analysis of plant mitochondria.
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Lloyd, Samantha M. "The pollination ecology and reproductive success of the Australian shrub Grevillea macleayana." Access electronically, 2006. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20070322.163537/index.html.
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Martins, Valeria Forni. "Dispersão direcional por formigas e fase regenerativa pos-dispersão da especie ruderal Ricinus communis L. (Euphorbiaceae)." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315983.
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Orientadores: João Semir, Claudia Regina Baptista HaddadDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: A reprodução vegetal por meio de sementes compreende duas fases: a de regeneração dos indivíduos de uma população e a de estabelecimento dos adultos. A fase regenerativa consiste de uma série de estádios, como liberação, dispersão, dormência/quiescência e germinação de sementes, e estabelecimento de plântulas, cada um com variações na duração e no mecanismo de acordo com a espécie ou a população. Desta forma, a dispersão de sementes é a etapa do ciclo reprodutivo das plantas que inicia a renovação das populações vegetais. Vantagens da dispersão incluem a deposição desproporcional mente maior de sementes em sítios que são melhores para a sobrevivência de sementes e o estabelecimento de plântulas, sendo estes os componentes da hipótese de dispersão direcionaI. Apesar da dispersão direcional ser considerada de comum ocorrência e de grande importância ecológica, há poucos exemplos descritos na literatura. No entanto, um dos casos mais reconhecidos é a mirmecocoria, ou dispersão de sementes por formigas. Ricinus communis, popularmente conhecida como mamona, tem sementes tipicamente mirmecocóricas que são dispersas secundariamente por formigas. Estes insetos carregam as sementes com elaiossomo até seus ninhos, onde retiram e retêm este apêndice, e descartam as sementes sem elaiossomo no exterior dos formigueiros. Assim, formigas podem atuar como dispersores direcionais de R. communis, além de provavelmente desempenharem um importante papel na germinação de suas sementes, uma vez que é atribuída a existência de substâncias inibidoras de germinação ao elaiossomo. É popularmente conhecido que R. communis forma bancos de sementes persistentes, apesar de não existirem registros científicos dos mesmos. Devido à capacidade de ocupar os mais diversos habitats após perturbação, o que pode ser atribuído à regeneração a partir de bancos de sementes, esta espécie é considerada ruderal. Os objetivos deste estudo foram determinar se R. communis apresenta dispersão direcional por formigas e se a ocupação de novos habitats pode ser atribuída às possíveis características ruderais da fase regenerativa pós-dispersão desta espécie. Foi encontrado um maior número de sementes sem elaiossomo, plântulas e jovens de R. communis nos locais de descarte de formigueiros, e sementes com elaiossomo foram igualmente encontradas nestes locais e em suas redondezas. A remoção de sementes pós-dispersas de R. communis não diferiu entre locais de descarte de formigueiros e suas redondezas. A remoção apresentou um pequeno aumento ao longo do tempo e foi inversamente dependente de densidade. No entanto, a redução da remoção não foi proporcional ao aumento da densidade dê sementes originalmente depositadas nos locais de descarte de formigueiros e em suas redondezas. Solos de formigueiros não apresentaram maior concentração de nutrientes, e não houve diferença no número de sementes germinadas e no vigor de jovens entre locais de descarte de formigueiros e suas redondezas. Além disto, formigas não conferiram proteção diferencial contra herbivoria às plântulas crescendo nos locais de descarte de seus ninhos. Sementes de R. communis de diferentes idades apresentaram respostas de germinação distintas, porém, foi observada germinação em todas as condições às quais foram expostas. Além disto, sementes com um ano não apresentaram resposta de germinação esperada para sementes que são incorporadas em bancos de sementes. Foram encontradas poucas sementes viáveis de R. communis no solo, apesar de ser observada emergência maciça de plântulas após perturbação do solo em diversas áreas. A espécie é heliófila, porém capaz de ocupar habitats consideravelmente sombreados. Além disto, R. communis é uma fraca competidora, mas é capaz de se estabelecer em áreas que têm alta densidade de indivíduos. O presente estudo demonstrou que a deposição de sementes pós-dispersas em locais de descarte de formigueiros não confere vantagens adicionais a R. communis e que formigas não atuam como dispersores direcionais desta espécie. Além disto, R. communis não apresenta todas as características típicas de plantas ruderais, e seu sucesso em colonizar os mais variados habitats pode ser atribuído à sua plasticidade de respostas às diversas condições ambientais
Abstract: Plant reproduction through seeds has two phases: the regeneration of the individuals of a population and the establishment of the adult plants. The regenerative phase consists of many stages, such as seed release, dispersal, dormancy/quiescency and germination, and seedling establishment, each with differences in duration an? in mechanisms according to the species or to the population. In this way, seed dispersal is the event of plant reproduction cycle that initiates plant population regeneration. Advantages of seed dispersal include the disproportional higher seed deposition in micro-habitats that are more suitable for seed survival and seedling establishment, which are the components of the directed dispersal hypothesis. Although directed dispersal is considered common and ecologically important, few examples are described in literature. However, one of the best-known cases is myrmecochory, or seed dispersal by ants. Ricinus communis, the commonly known castor, has typical myrmecochorous seeds that are secondarily dispersed by ants, which remove seeds with elaiosome into their nests and discard them out in the pile mound without the appendage. Therefore, ants may act as directed dispersers of this species, and may also play a major role in seed germination, once the elaiosome of R. communis seeds is regarded as having germination inhibitory substances. It is commonplace that this species forms persistent soil seed banks, though no study has demonstrated the existence of such seed banks. Due to its ability to occupy the most different habitats after local disturbance, which may be attributed to the regeneration through seed banks, R. communis is considered a ruderal species. This study aimed to determine whether seeds of R. communis present directed dispersal by ants and whether the ruderal features of the post-dispersal regenerative phase assure the species ability to successfully occupy new habitats. There was a greater number of R. communis seeds without elaiosome, seedlings and juveniles in ant nest pile mounds, and seeds with elaiosome were equally distributed between the pile mounds and their vicinities. The removaI of post-dispersed seeds of R. communis from the pile mounds did not differ from the removal in their vicinities. AIso, the removal presented a small increase along time and was inversely density-dependent. However, the reduction in the removal was not proportional to the rise in the density of seeds originally placed in the pile mounds and in nheir vicinities. Ant nest pile mound soils were not nutrient-enriched, and we found no differences in the number of germinated seeds and in the juveniIe vigor measurements between the pile mounds and their vicinities. Also, ants did not provide differential protection for seedlings in the piles mounds against herbivores. Fresh and one year old seeds presented distinguished germination response, although they germinated in all conditions they were submitted to. Also, one year oId seeds did not present typical germination response of seeds that may constitute seed banks. We found few viable seeds of R. communis in the soil, though massive seedling emergence after soil disturbance was observed in many sites. Ricinus communis is light-demanding, but may occupy pretty shady sites. Also, the species is a poor competitor, especially with individuaIs of other species, but is capable of establishing in areas with high density of individuaIs. This study demonstrated that the deposition of post-dispersed seeds in the pile mounds does not provide additional advantages for R. communis and that ants do not act as directed dispersers of this species. AIso, R. communis does not present all typicaI features of ruderal plants, and its success in coIonizing the most different habitats may be attributed to the species' plasticity facing environmentaI conditions
Mestrado
Mestre em Ecologia
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Davison, Elizabeth. "Plant Selection and Selecting Your Plants." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/144757.
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8 pp.The majority of maintenance requirements and plant problems result from either selecting the wrong kind of plant for a location or from planting an inferior specimen of the selected plant type. The first decision is called Plant Selection and the second one is Selecting Plants. This publication covers the factors involved in making good decisions to install the right plant in the right place.
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Davison, Elisabeth, John Begeman, Jimmy Tipton, and Tom DeGomez. "Plant Selection and Selecting Your Plants." College of Agriculture, University of Arizona (Tucson, AZ), 2015. http://hdl.handle.net/10150/560978.
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Revised; Originally Published: 20008 pp.
Whether you are beginning a new landscape or renovating an existing one, planning ahead can prevent many problems. The majority of maintenance requirements and plant problems result from either selecting the wrong kind of plant for a location or planting an inferior specimen of the selected plant type. In other words, there are two decisions to be made: ▪ What species, or kind, of tree are you going to buy — an oak, pine, mesquite, or acacia? ▪ Assuming you decide on an oak, which one in the row of oaks at the nursery are you going to buy? The first decision is called Plant Selection and the second is Selecting Plants. Our goal is to install the right plant in the right place. This publication will cover the factors involved in making good decisions to achieve this goal.
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Gosper, Carl R. "Consequences of weed invasion and control on plant-bird interactions and bird communities." Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20050221.155953/index.html.
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Chikkala, Veera, and veera chikkala@rmit edu au. "Production and transformation of tobacco and Brassica containing macrochloroplasts." RMIT University. Applied Sciences, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091005.144005.
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Plastid division, sustained by the equilibrium expression and coordination of plastid division genes is vital for the maintenance of plastid populations in dividing plant cells. Macrochloroplasts (MCP), the occurrence of one or a few chloroplasts per cell is due to the imbalance in the expression of plastid division genes. Because of the MCP size and number it was proposed that they may provide better targets for the plastid transformation than the normal (WT) chloroplasts and result in better plastid transformation frequencies. The objective of this research was to produce transgenic plants containing macrochloroplasts by nuclear transformation and then to use these plants as a model for the development of plastid transformation of crop species. By using AtFtsZ1-1 and AtMinD1 as query sequences in the TIGR (U.S.A) and ASTRA (Australia) Brassica oleracea EST databases, this project resulted in the isolation of cauliflower FtsZ1-1 (EU684588) and MinD (EU684589) genes. In addition, AtFtsZ1-1 was used as a control gene for comparison to the cauliflower FtsZ1-1. Binary vectors were constructed to express these genes in tobacco and cauliflower either by Agrobacterium tumefaciens-mediated or PEG-mediated transformation methods. Transgenic tobacco and cauliflower plants with abnormal chloroplasts (MCP, minichloroplasts, honeycomb or doughnut shaped chloroplasts, uneven surface membrane chloroplasts) were developed. Furthermore, the transgenic tobacco and cauliflower plants were examined by PCR, RT-PCR and Southern blotting. In addition, th ese plants were also analysed for the different abnormal chloroplast phenotypes by fluorescence microscopy. This project also generated the first plastid transformants from macrochloroplast bearing tobacco plants via biolistics. After one round of regeneration homoplasmic plastid transformants were obtained from both WT chloroplast and MCP tobacco plants. The homoplasmic nature of plastid transformants were confirmed by PCR and Southern blotting. Plastid expression of GFP in WT and MCP was confirmed by fluorescence/confocal microscopy and western blot analysis. This project showed for the first time the characterisation of cauliflower FtsZ1-1 and MinD plastid division genes in homologous and heterologous systems (cauliflower and tobacco). Moreover, obtaining homoplasmic plastid transformant shoots from one round of regeneration from the MCP containing tobacco plants is reported for the first time in this study. In addition this study explored the effect of transgene expression level on the chloroplast abnormality, highlighting the importance of analysing transgenic tobacco and cauliflower plants at the protein lev el specifically with regard to plastid division genes. The maintenance of MCP phenotype in the regenerated shoots and the requirement of standardisation of MCP containing plants via biolistics for increasing the plastid transformation frequency were also examined.
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Minnis, Andrea Margaret Bennett, and andreaminnis@bigpond com. "A Substantive Theory to explain the Impact of Living with a Chronic Wound whilst receiving Conflicting or Inappropriate Advice or Care." RMIT University. Health Sciences, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091015.094743.
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It is estimated that over 200,000 Australians have problem or chronic wounds at any one time (Australian Wound Management Association, 2008). Over the past 4 decades while there has been significant advancement in wound care, a high proportion of wounds become chronic. Despite the availability of wound care resources and specialist services, there remains an inconsistency in the management of chronic wounds that impacts both on the quality of life of individuals with chronic wounds and the health care budget (Harding 2002). Using a Grounded theory approach, the aim of this study was to explore and describe the impact of living with a chronic wound and findings indicate that individuals living with a chronic wound are receiving conflicting or inappropriate advice and care. Individuals living with a chronic wound experience a life of uncertainty related to the struggle to endure a wounded body and the layers of professional care they receive. When they are provided with conflicting or inappropriate advice and treatment, inconsistencies of care and poor coordination of care, layers of unnecessary burden are added to their experience. The uncertainty and dissonance individuals are faced with, leads them to question their care, themselves and the expertise and professionalism of their treating health professionals. As a result, they experienced a loss of respect and trust for their treating health professionals and a loss of confidence in their care. Chronic wounds impose of individuals, an intense burden of physical suffering, cause major disruption to the normality of their lives, and often entail a constant personal struggle to secure appropriate care and understanding from their treating health professionals. In order to enable individuals living with chronic wounds to develop appropriate coping strategies, it is essential that health professionals: understand the burden of suffering associated with living with a chronic wound; ensure that they develop and maintain a high level of knowledge with regards to contemporary wound care practices; ensure that their clientele are provided with high quality care information that is based on the best available evidence; ensure continuity of care; and foster quality professional-client relationships that negates the need for individuals to have to constantly question their care.
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Lim, Grace T. "Enhancing the weaver ant, Oecophylla smaragdina (Hymenoptera: Formicidae), for biological control of a shoot borer, Hypsipyla robusta (Lepidoptera: Pyralidae), in Malaysian mahogany plantations." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/26850.
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The weaver ant is a promising biological control agent of a shoot borer, Hypsipyla robusta Moore, on mahogany, but techniques to conserve ant colonies redistributed to mahogany plantations have not yet been developed. The effect of food supplementation and host plant species preference of the weaver ant, Oecophylla smaragdina F., was evaluated in a series of field studies.
A simple model was developed to estimate the number of ants within nests on Khaya ivorensis A. Chev. (Meliaceae): log₁₀ (Number of ants) = - 1.16 + 1.09 log₁₀ (Nest size). Nest size is calculated from estimated nest height (ĥ) and length (à ) using the formula = π;r²⁺; à , where r = ½ ĥ. This model was useful for repeated assessments of ant population levels to evaluate treatment effects. It provides better estimates than previous indirect methods based on nest counts and ant trail counts on plant parts.
Colonies that were relocated without their queens and very small colonies (< 10,000 ants) failed to establish on new host trees, indicating that a minimum ant population and queen needs to be transferred for colony survival. Established colonies consumed more high-protein foods (live mealworms and fish) than high-carbohydrate liquid foods (honey and –weaver ant formula–, which contained sucrose and human muscle-training powder (Enerpro™)). Relocated colonies consumed more weaver ant formula and as many mealworms as established colonies, indicating that existing and relocated colonies require different food supplementation strategies. Decreasing consumption over time and preferential consumption among high-protein food choices (i.e., of mealworms over fish) indicated that ants select and regulate food consumption based on colony needs. Therefore, food supplementation should be as needed. Preliminary indications were that self-sufficiency in trophobiont (honeydew) levels may be achieved in two months after colony relocation.
The optimal colony density that would protect K. ivorensis was estimated to be within the range of 6 – 48 colonies per ha based on previous reports for cocoa and cashew, and a consideration of the low damage threshold for mahogany. Substituting chemical control with weaver ants at those application rates gave similar IRRs (Internal rate of return; 11.6 – 12.2 vs. 12.0%) in preliminary financial analyses, and was preferable from an ecological standpoint.
Twenty-nine host plant species were found for Malaysian O. smaragdina, of which 11 were new species records for Oecophylla spp. Also, there were two new genera and eight new species records for Malaysian O. smaragdina. Of eight trophobiont families collected, six species were identified, yielding new trophobiont-host plant species records for four coccoid species and two membracid genera. Screening of several ant-abundant plant species that included preliminary pest risk analyses for trophobionts on K. ivorensis, identified M. citrifolia as a promising candidate for mixed-planting with this mahogany species.Ph. D.
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Winger, Alison Marie. "Impact of 4-hydroxy-2-nonenal in Arabidopsis mitochondria." University of Western Australia. Biochemistry and Molecular Biology Discipline Group, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0121.
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[Truncated abstract] A range of biotic and abiotic stresses increase levels of reactive oxygen species (ROS) in plants due to perturbations of chloroplast and mitochondrial metabolism and the generation of ROS in defence responses. The polyunsaturated fatty acids of membrane lipids are susceptible to ROS induced peroxidation yielding various aldehydes, alkenals and hydroxyalkenals including the cytotoxic compound 4-hydroxy- 2-nonenal (HNE). HNE has the potential to cause substantial oxidative damage in cells via its reactivity with sulfhydryl groups of cysteine (Cys) and lipoic acid, the imidazole group of histidine (His) and the ?-amino group of lysine (Lys) protein residues. Analysis of the components of the plant respiratory electron transport chain to HNE revealed a particular susceptibility to inhibition of activity of the alternative oxidase (Aox). Incubation with HNE prevented dimerisation of Aox protein, suggesting that one site of modification was the conserved cysteine residue involved in dimerisation and activation of this enzyme (Cys1). However, a naturally occurring isoform of Aox lacking Cys1 and unable to dimerise, LeAox1b from tomato, was equally sensitive to HNE inhibition, showing that other amino acid residues in Aox also interact with HNE and are likely responsible for inactivation of the enzyme. ... The broader impact of HNE on the whole Arabidopsis mitochondrial proteome was examined by use of various 2-dimensional gel separation techniques coupled with use of HNE-adduct antibodies. 32 proteins involved in a number of mitochondrial functions were found to be susceptible to modification by HNE, including components of the electron transport chain, the TCA cycle, as well as proteins involved amino acid metabolism and stress-responses. Implications of modification of these proteins by HNE are discussed. As HNE is produced in vivo during oxidative stress, the profile of mitochondrial targets of HNE was examined from Arabidopsis cell cultures exposed to various oxidative stress inducers. Menadione and hydrogen peroxide induced oxidative stress throughout the cell, while antimycin A initiated a mitochondrial targeted stress. A differential profile of mitochondrial proteins was observed to be modified by HNE in the various treatments. These results also showed that induction of stress within a whole cell can impact lipid peroxidation within the mitochondria. Overall, this work showed the presence and production of HNE in plant cells, and that HNE, both exogenous and endogenous, has the ability to modify a specific subset of mitochondrial proteins. In several cases this HNE modification was shown to have functional or structural consequences.
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Dolling, P. J. "Lucerne (Medicago sativa) productivity and its effect on the water balance in southern Western Australia /." Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0108.
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村瀬, 香., and Kaori MURASE. "オオバギーアリ共生系における種特異性の維持機構に関する生態学的研究." 名古屋大学農学部附属演習林, 2003. http://hdl.handle.net/2237/8603.
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Schymanski, Stanislaus Josef. "Transpiration as the leak in the carbon factory : a model of self-optimising vegetation." University of Western Australia. School of Environmental Systems Engineering, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0095.
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Fuentes, Hector David. "Studies in the use of plant growth regulators on phytoremediation /." View thesis View thesis, 2001. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030505.150607/index.html.
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Thesis (Ph.D.) -- University of Western Sydney, Macarthur, 2001.A thesis presented to the University of Western Sydney, in partial fulfillment of the requirements for the degree of Doctor of Philosophy, December, 2001. Bibliography : leaves 163-173.
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Mulyati. "Zinc requirements of transplanted oilseed rape." Murdoch University, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20060109.135933.
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Transplanting is a common practice for many horticultural crops and some field crops. Recently, transplanted oilseed rape (Brassica napus L.) crops have been reported to be sensitive to zinc (Zn) deficiency. However, Zn nutrition in transplanted field crops has not been investigated in detail. The objectives of this present research were to investigate whether transplanting increases external Zn requirements of transplanted oilseed rape, and the mechanisms of root function, growth and Zn uptake after transplanting including rhizosphere modification capacity by plant roots. The second objective was to examine the relative effects of root pruning and transplanting on Zn responses of oilseed rape, and the third objective was to determine external and internal Zn requirements of transplanted oilseed rape for diagnosing and predicting Zn deficiency.
An experiment on a low Zn sand (DTPA extractable Zn 0.14 mg kg-1) was set up to determine whether transplanted oilseed rape had a higher Zn requirement than that of direct-sown plants. Low Zn supply depressed shoot dry weight, however, root growth was relatively more strongly suppressed than shoots. Maximum root dry weight required much higher external Zn for transplanted plants compared to direct-sown plants, whilst shoot dry weight required a similarly low external Zn supply. In addition, transplanted plants were sensitive to zinc deficiency during the early post-transplanting growth, and the response weakened as the plants recovered from root injury or transplanting stress. However, the transplanted plants also experienced root pruning before transplanting and so in this experiment the higher Zn requirement could have been due to root pruning or transplanting or both.
A further experiment was undertaken to determine the comparative external Zn requirements of direct-sown and transplanted plants in well-stirred chelate-buffered solution culture where a rhizosphere effect on plant availability of Zn forms is absent and the effects of poor root-soil contact on post-transplanting growth are minimized. In solution culture at the same level of Zn supplied, direct- sown plants produced higher shoot and root dry matter and greater root length than those of transplanted plants. However, since a higher external Zn requirement was found for transplanted plants in buffered solution culture than for direct- sown plants, it was concluded that the higher Zn requirement was not related to decreased rhizosphere modification, to greater demand for Zn or to poor root-solution contact, but rather to the time required for transplanted plants to recover from transplanting and root injury. The recovery of root function in solution culture was more rapid than that in soil culture and expressed as a higher Zn requirement for shoot as well as root growth. It suggested that the delay in root recovery in soil culture was due to slower absorption of Zn from the soil after transplanting than was the case in solution culture.
Chelate-buffered nutrient solution culture and harvesting plants successively at 5 day intervals until 25 days after transplanting was used to examine the mechanisms of the recovery of root growth and function. In this experiment, the external Zn requirement of transplanted plants was investigated with unpruned or pruned root systems. Plants with unpruned root system and sufficient Zn supply exhibited faster recovery from transplanting than those with pruned root system plants. The results suggest that root pruning impaired Zn uptake by plant roots and slowed down the root and shoot growth after transplanting. Increased solution Zn partly alleviated the effects of root pruning and presumably this is a major reason why transplanted oilseed rape had a high external Zn requirement. However, root pruning also appeared to impair water uptake, and may have suppressed shoot growth through sequestering carbon for new root growth and through decreased phytohormone production by roots.
Since rapid root recovery of transplanted plants is essential for successful of growth in the field, Zn application to the nursery bed was explored as a starter fertilizer to stimulate root growth after transplanting. The objective of this experiment was to determine whether increasing the seedbed Zn would stimulate new root growth of transplanted oilseed rape, and therefore would alleviate the need for increased external Zn for post-transplanting growth. Results showed that adequate Zn concentration in the seedbed promoted the post-transplanting growth by stimulating the new root growth especially increased root length, and also hastened the recovery of root systems. However, high Zn concentration at transplanting still had a more dominant effect in stimulating the new root growth of oilseed rape after transplanting.
The final experiment was set up using rhizobags with three rates of Zn supply and unpruned or pruned root systems. The purpose of this study was to investigate the chemical change in the rhizosphere and non-rhizosphere or bulk soil and its relationship to the recovery of root function after transplanting, and also to identify and quantify the organic acids in soil extracts of direct-sown and transplanted plants. The rhizosphere soil pH was lower than that of non-rhizosphere soil, and the decrease of soil pH was suggested as the mechanism of the increase of Zn availability and mobility in the rhizosphere soil. Direct-sown plants were more efficient in utilizing Zn than those of transplanted plants especially compared to those of plants with pruned root system. Zinc deficient plants excreted higher concentration of organic acids particularly citric acid, suggesting this was a mechanism of Zn mobilization and Zn uptake by roots of oilseed rape.
The main implications of the present study for the management of Zn nutrition of transplanted crops were: the need to increase the Zn application to crops in the nursery and at transplanting compared to direct-sown plants; the possibility that external requirements of other nutrients will be greater in transplanted crops also requires further consideration; and in cropping systems where transplanting is practised, greater attention should be given to the avoidance of root damage during the transplanting.
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Clifton, Rachel. "The alternative oxidase gene family in arabidopsis : insights from a transcriptomic study /." Connect to this title, 2005. http://theses.library.uwa.edu.au/adt-WU2006.0004.
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Cruz, Nayara Gomes da. "Formigas associadas a Turnera subulata (Turneraceae) : custos e/ou benefícios para planta hospedeira?" Universidade Federal de Sergipe, 2016. https://ri.ufs.br/handle/riufs/4476.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESEcological interactions between organisms are complex and can present dynamic results, which are dependent on environmental context. Plants with extrafloral nectaries attract a wide variety of ants species, in associations commonly considered mutualistic. In tropical environments the combination of plants and ants play an important role in communities. Turnera subulata is a ruderal shrub widely distributed in disturbed areas, which has a pair of extrafloral nectaries in the base of each leaf. In this study, we evaluated whether the ants associated with T. subulata: (i) vary spatially (between locals) and temporally (over day period); (ii) respond to simulate presence of herbivores and the signs of damage caused in different structures of the host plant (stem and leaf); (iii) reduce herbivory rates; (iv) influencing the vegetative growth and reproductive success of the host plant, along its phenology. The experiments were conducted in São Cristóvão-SE. For the initial understanding of the system studied, T. subulata individuals were selected, in which we performed simulations of the presence of herbivorous and realization of injuries in the stem and leaves of the host plants. The total number of individuals and species associated ants was quantified during three periods of the day. It was quantitated the percentage of leaf area lost and leaves attacked by sucking. They also plot experiments were performed in which were established with and without ants. In each plot were transplanted T. subulata seedlings that were followed throughout their phenological stages. Observations were made in order to quantify the vegetative growth and reproductive investment measures the host plant as well as the number of sheets to damage by sucking insects and chewing; and the number of herbivores. The number of visitors associated with T. subulata was quantified during three periods of the day, being held 5min observation / share. In all cases, data were analyzed using general linear models. 21 species of ants were found. The composition of the ant meeting showed significant variation between locations and time of day. Visitation rates and predation by ants was higher in stems than in the leaves of plants. In general, herbivory rates were not correlated with the association / activity of ants, with the exception of leaf area proportion consumed, which showed a significant reduction in plants where the ants defended the leaves. The results showed that the maturation stage there was a trade-off between growth x propagation of plants; which is favorable for plants (ex.: higher reproduction) who were in plots with ants. Plants on treatment with ants had fewer visitors, including predators and parasitoids. The number of sucking herbivores was significantly reduced in the presence of ants, during the flowering stage. Our results suggest that the benefits of the association may be dependent on context. Moreover, they can contribute to the understanding of the mechanisms involved in facultative interactions between ants and plants and to the understanding of the communities in interaction nets.
Interações ecológicas entre organismos são complexas, podendo apresentar resultados dinâmicos, os quais são dependentes do contexto ambiental. Plantas com nectários extraflorais atraem uma ampla variedade de espécies de formigas, em associações comumente consideradas mutualísticas. Nos ambientes tropicais a associação de plantas e formigas desempenha importante papel nas comunidades. Turnera subulata é um arbusto ruderal, amplamente distribuído em áreas antropizadas, que apresenta um par de nectários extraflorais na base de cada folha. Neste estudo, avaliamos se as formigas associadas a T. subulata: (i) variam espacialmente (entre locais) e temporalmente (ao longo do período do dia); (ii) respondem à simulação da presença de herbívoros e aos sinais de danos ocasionados em diferentes estruturas da planta hospedeira (caule e folha); (iii) reduzem as taxas de herbivoria; (iv) influenciam o crescimento vegetativo e sucesso reprodutivo da planta hospedeira, ao longo da sua fenologia. Os experimentos foram realizados em São Cristóvão-SE. Para o entendimento inicial do sistema estudado, foram selecionados indivíduos de T. subulata, nos quais realizamos simulações da presença de herbívoro e realização de injúrias no caule e folhas das plantas hospedeiras. O número total de indivíduos e de espécies de formigas associadas foi quantificado durante três períodos do dia. Foi quantificada a proporção de área foliar perdida e de folhas atacadas por sugador. Também foram realizados experimentos em que foram estabelecidas parcelas com e sem formigas. Em cada parcela foram transplantadas mudas de T. subulata que foram acompanhadas ao longo de seus estágios fenológicos. Foram feitas observações a fim de quantificar as medidas de crescimento vegetativo e investimento reprodutivo da planta hospedeira, assim como o número de folhas com danos por insetos sugadores e mastigadores; e o número de herbívoros. O número de visitantes associados a T. subulata foi quantificado durante três períodos do dia, durante 5min de observação/parcela. Em todos os casos, os dados foram analisados através de modelos lineares generalizados. Foram encontradas 21 espécies de formigas. A composição da assembleia de formigas apresentou variação significativa no espacialmente e temporalmente. As taxas de visitação e de predação pelas formigas foi maior no caule do que nas folhas das plantas. De forma geral, as taxas de herbivoria não foram correlacionadas com a associação/atividade das formigas, com exceção da proporção de área foliar consumida, que mostrou redução significativa em plantas onde as formigas defenderam as folhas. Os resultados mostraram que no estágio de maturação houve um trade-off entre crescimento x reprodução das plantas; sendo este favorável (ex.: maior reprodução) para as plantas que estavam em parcelas com formigas. Plantas sobre tratamento com formigas tiveram menor número de visitantes, incluindo predadores e parasitoides. O número de herbívoros sugadores foi significativamente reduzido na presença de formigas, durante o estágio de floração. Nossos resultados sugerem que os benefícios da associação podem ser dependentes de contexto. Além disso, podem contribuir para a compreensão dos mecanismos envolvidos nas interações facultativas entre formigas e plantas, e para o entendimento das redes de interações em comunidades.
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