Dissertations / Theses: 'Vesicular-arbuscular mycorrhizas. Plants Fungicides'

1

Sukarno, Nampiah. "Effects of selected fungicides on vesicular-arbuscular mycorrhizal symbiosis." Title page, contents and summary only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phs948.pdf.

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Francis, R. "The biology of vesicular-arbuscular mycorrhizas with special reference to their role in nutrient transfer between plants." Thesis, University of Sheffield, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380957.

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Wu, Fuyong. "Colonization and species diversity of arbuscular mycorrhizal fungi and their efffects on metal tolerance and metal accumulation in two metal hyperaccumulators, Pteris vittata L. and Sedum alfredii Hance." HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/931.

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Gasch-Salava, Caley. "Comparison of vegetation, soil, and AM fungal activity in native and exotic annual brome dominated Wyoming rangeland." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1594494571&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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Workman, Rachael Elizabeth. "Effects of Arbuscular Mycorrhizal Fungal Infection and Common Mycelial Network Formation on Invasive Plant Competition." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/2025.

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Understanding the biotic factors influencing invasive plant performance is essential for managing invaded land and preventing further exotic establishment and spread. I studied how competition between both conspecifics and native co-habitants and arbuscular mycorrhizal fungal (AMF) impacted the success of the invasive bunchgrass Brachypodium sylvaticumin early growth stages. I examined whether invasive plants performed and competed differently when grown in soil containing AMF from adjacent invaded and noninvaded ranges in order to determine the contribution of AMF to both monoculture stability and spread of the invasive to noninvaded territory. I also directly manipulated common mycelial network (CMN) formation by AMF to determine hyphal network contribution to competitive interactions. I found that invasive plants performed most poorly (as indicated by decreased chlorophyll content, size and shoot dry mass) in invaded range soil against conspecifics. This could be two-pronged evidence for existing biotic pressure on the invasives to expand into adjacent noninvaded ranges. I also found a negative effect of AMF colonization and invasive plant performance, potentially indicating deleterious plant-soil feedbacks which could help maintain plant biodiversity at a community level. CMN effects were found to be interactive with root competition and directly affected the performance and nutrient status of B. sylvaticum. Although no direct correlations between AMF colonization levels and competition were found, CMN presence contributed significantly to plant growth and nutrient status. Therefore AMF, through infection and CMN formation, may be able to influence invasive plant growth and spread in the field.

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Tbaileh, Tarek. "Effect of Azoxystrobin and Arbuscular Mycorrhizal Fungal Colonization on Four Non-Target Plant Species." Thesis, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23550.

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Azoxystrobin (AZY), a systemic broad-spectrum fungicide, is applied on crops to control soil-borne pathogenic fungi. This study aimed to determine the effects of AZY on non-target plant species and Glomus intraradices Schenck & Smith, an arbuscular mycorrhizal fungus (AMF) associated with plants' roots. We hypothesized that AZY negatively affects AMF viability; and that, if the plants were dependent on this symbiosis, AZY exerts an indirect detrimental effect on plant growth. To test this, three mycotrophic (Phalaris arundinacea L., Solidago canadense L., Geum canadense Jacq.) and one non-mycotrophic (Chenopodium album L.) native plant species were subjected to five AZY doses with or without AMF. Plants were grown for 60 days in a greenhouse, in individual pots, (4 plants X 2 AMF X 5 AZY X 6 replicates), and mesocosms (1 mes. X 2 AMF X 5 AZY X 6 replicates), and harvested 30 days after spraying, and dry mass was taken. Fresh root samples were used for microscopic assessment of AMF colonization. The results from the individual pot experiment show that the effects of AZY on biomass varied across plant species. AZY led to a significant increase in shoot and root mass of P. arundinacea, and a decrease in shoot mass of AMF inoculated G. canadense. The presence of AMF resulted in a significant increase in root and shoot mass of P. arundinacea, and an increase in root mass of S. canadense and shoot mass of C. album. In the mesocosm experiment AZY did not have a significant effect on the measured parameters, although the presence of AMF significantly increased root, shoot, and total dry mass of G. canadense and P. arundinacea. Conversely, AMF significantly decreased shoot and total dry mass of S. canadense. The results suggest that both direct and indirect effects should be taken into account when assessing the impact of pesticides on non-target plant species.

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Leung, Ho Man Homan. "Interactions of arbuscular mycorrhizal fungi with an arsenic hyperaccumulator plant (pteris vittata) on the uptake of arsenic." HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/945.

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Chan, Wai Fung. "The roles of arbuscular mycorrhizal fungi in arsenic uptake and tolerance of upland rice." HKBU Institutional Repository, 2011. http://repository.hkbu.edu.hk/etd_ra/1257.

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Guillon, Christopher. "Systemic alteration of defense-related gene transcript levels in mycorrhizal bean plants infected with Rhizoctonia solani." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33767.

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A time course study was conducted to monitor disease development and expression of the defense-related genes phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), and hydroxyproline-rich glycoprotein (HRGP) in bean (Phaseolus vulgaris L.) plants colonized by the arbuscular mycorrhizal (AM) fungus Glomus intraradices , and post-infected with the soil-borne pathogen Rhizoctonia solani. Pre-colonization of bean plants by the AM fungus did not significantly reduce the severity of rot symptoms. RNA blot analysis revealed a systemic increase in transcript levels of the four defense-related genes in response to R. solani infection. On the other hand, pre-colonization of bean plants with G. intraradices elicited no change in PAL, CHS and CHI transcripts, but an increase of HRGP transcripts in leaves was detected. A differential and systemic alteration in the expression of all four defense genes was observed in AM beans post-infected with R. solani. Depending on the time after infection with R. solani and the tissue examined, varying responses from stimulation, suppression, to no change in transcript levels were detected.

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Podrebarac, Frances Ann. "The Relative Nitrogen Fixation Rate and Colonization of Arbuscular Mycorrhizal Fungi of Iron Deficient Soybeans." Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/29600.

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Soybeans (Glycine max L. Merr.) are a symbiont of two beneficial associations: biological nitrogen fixation (BNF) with Bradyrhizobium japonicum, and arbuscular mycorrhizal fungi (AMF). Within the Northern Great Plains of the USA, iron deficiency chlorosis (IDC) of soybean is a yield-limiting factor. The effects of IDC on BNF and AMF are not well defined. This study was conducted to determine the effects of IDC on BNF and AMF. A laboratory study was performed to compare three methods of measuring ureide-N, a product of BNF in soybeans. Field studies in soybean were performed at three locations at eastern N011h Dakota. The experimental design was a factorial combination of three cultivars and three treatments. The three cultivars, in order of decreasing chlorosis susceptibility, were NuTech NT-0886, Roughrider Genetics RG 607, and Syngenta S01-C9 RR. The three treatments were control, Sorghum bicolor L. companion crop planted with the soybean seed, and FeEDDHA applied with the soybean seed. Chlorosis severity was the greatest and least for the NuTech and Syngenta cultivars, respectively. The FeEDDHA treatment decreased chlorosis severity. Ureide levels were abnormally high in plants severely stunted by JDC. The excess accumulation of ureides in IDC-stunted plants suggests that plant growth was reduced more than the rate of nitrogen fixation. The AMF population \vas at an adequate level at all locations and not affected by cultivar or treatment, in general. In the laboratory study, the Patterson et al. method had greater ureide concentrations due to the non-specific measuring of ammonium compounds compared to the Vogels and Van der Drift and Goos methods. North Dakota Soybean Council

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Li, Hui. "The role of arbuscular mycorrhizal fungi (AMF) on the tolerance and accumulation of arsenic in rice (Oryza sativa L.)." HKBU Institutional Repository, 2012. https://repository.hkbu.edu.hk/etd_ra/1409.

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Lee, Caitlin Elyse. "Assessment of Arbuscular Mycorrhizal Symbiosis on Invasion Success in Brachypodium sylvaticum." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/2108.

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The effects that mutualistic soil biota have on invasive species success is a growing topic of inquiry. Studies of the interactions between invasive plants and arbuscular mycorrhizal fungi (AMF) have shown changes in AMF community composition, reductions in AMF associations in invasive plants, and changes in native species fitness and competitive outcomes in invasive-shifted AMF communities. These findings support the degraded mutualist hypothesis, where invasive species alter the mutualist community composition, resulting in detrimental associations with the new mutualist community for native species. Here I present two studies that examine various aspects of the arbuscular mycorrhizal fungal (AMF) mutualism in the success of a newly invasive bunchgrass, Brachypodium sylvaticum. The first chapter is a field survey of AMF associations between a native bunchgrass, Elymus glaucus and B. sylvaticum in the invaded range. The second chapter presents a test of reduced mycorrhizal dependence between invasive and native-range populations of B. sylvaticum. For the field survey, AMF colonization and spore density of root and soil rhizosphere samples from B. sylvaticum and E. glaucus from the two regions of introduction of the B. sylvaticum invasion were measured. In this survey I found lower AMF colonization and spore density in B. sylvaticum compared to the native species in the invaded ranges. The reduction in AMF associations in B. sylvaticum was predicted to be due to the evolution of reduced mycorrhizal dependence in invasive populations compared to native populations of B. sylvaticum. I tested the prediction for reduced mycorrhizal dependence by measuring the fitness gains or losses with AMF inoculation compared to sterile conditions in both fertilized and unfertilized treatments for individuals of B. sylvaticum from each of the introduction sites in Oregon, USA and source populations from the native range in Europe. There were no differences in plant or AMF fitness between the invasive and native populations of B. sylvaticum. Under high nutrients the interaction between all B. sylvaticum plants and AMF was mutualistic. Under low nutrient treatments both B. sylvaticum and AMF had reduced fitness measures, suggesting a competitive interaction. Nutrient levels of inoculated unfertilized soils are similar to field conditions. It is likely that the reduction in AMF associations in B. sylvaticum observed in the field is due antagonistic interactions between AMF and B. sylvaticum.

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Cheeke, Tanya Elizabeth Amy. "An Evaluation of the Nontarget Effects of Transgenic Bacillus thuringiensis Maize on Arbuscular Mycorrhizal Fungi in the Soil Ecosystem." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1027.

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My dissertation research examined the effect of the cultivation of insect-resistant Bacillus thuringiensis (Bt) maize on the soil environment with a goal of understanding how to obtain a balance between technological advancement and maintenance of a healthy soil ecosystem. Although Bt plants may help to reduce pesticide use, conferring benefits to farm workers and the environment, there are still unresolved questions about how the cultivation of Bt plants affects soil organisms. For this dissertation project, I used 14 different genotypes of Bt maize and non-Bt maize (Zea mays) to investigate the effects of transgenic Bt plants on the colonization ability, abundance, and diversity of symbiotic arbuscular mycorrhizal fungi (AMF) in the soil ecosystem over time. My greenhouse studies demonstrated that Bt maize plants exhibited reduced AMF colonization across multiple Bt genotypes and that effects were most pronounced when fertilizer levels were limited and spore density was high. In addition, I found that although differences in AMF colonization between Bt and non-Bt maize were difficult to detect in the field, spore density was reduced in Bt field plots after just one growing season. When I tested the effect of plot history on AMF and plant growth, I found that Bt and non-Bt maize plants had higher leaf chlorophyll content when grown in plots previously cultivated with the same maize line as the previous year, indicative of a positive feedback effect. I also examined potential mechanisms contributing to the reduced AMF colonization observed in Bt maize in greenhouse studies and determined that follow-up experiments should continue to investigate differences in root apoplastic invertase activity and root permeability in Bt and non-Bt maize. Future investigations would also benefit from examining potential differences in root exudate profiles and volatile organic compounds between Bt and non-Bt cultivars. Taken together, my dissertation results suggest that, while difficult to detect in the field, reductions in AMF colonization in Bt maize roots may be ecologically significant as they could lead to a decrease in the abundance of AMF propagules in the soil over time, potentially impacting soil structure and function in areas where Bt crop cultivation is high.

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Puta, Usanda. "Effects of genetically modified maize (MON810) and its residues on the functional diversity of microorganisms in two South African soils." Thesis, University of Fort Hare, 2011. http://hdl.handle.net/10353/419.

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Genetically modified (GM) crops are commercially cultivated worldwide but there are concerns on their possible negative impacts on soil biodiversity. A glasshouse study was conducted to determine effects of Bt maize residues on soil microbial diversity. Residues of Bt maize (PAN 6Q-308B) and non-Bt maize (PAN 6Q-121) were incorporated into the soil and corresponding maize seeds planted. The treatments were replicated three times. Fertilizer and water application were similar for both treatments. Rhizosphere and bulk soil was destructively sampled from each treatment and analyzed for microbial community level physiological profiles using Biolog plates with 31 different carbon substrates. Absorbance in the Biolog plates was recorded after 72 h of incubation at 20oC. Arbuscular mycorrhizal fungi spore counts were also determined. Field studies were conducted at the University of Free State and University of Fort Hare Research Farms to determine the effects of growing Bt maize on soil microbial diversity. One Bt maize cultivar (PAN6Q-308B) and non-Bt maize (PAN6Q-121) were grown in a paired experiment at University of Free State farm, while two Bt maize (DKC61-25B and PAN6Q-321B) and their near-isogenic non-Bt maize lines (DKC61-24 and PAN6777) were grown in a randomized complete block design with three replicates. Fertilization, weed control and water application, were similar for both Bt maize cultivars and their non-Bt maize counterparts. Rhizosphere soil samples were collected by uprooting whole plants and collecting the soil attached to the roots. The samples were analysed for microbial diversity and for arbuscular mycorrhizae fungal spore counts. Principal component analysis showed that soil microbial diversity was affected more by sampling time whereas genetic modification had minimal effects. Presence of residues also increased the diversity of microorganisms. Mycorrhizal fungal spores were not affected by the presence of Bt maize residues. Growing Bt maize had no effect on the soil microbial diversity in the rhizosphere.

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Sukarno, Nampiah. "Effects of selected fungicides on vesicular-arbuscular mycorrhizal symbiosis / Nampiah Sukarno." Thesis, 1994. http://hdl.handle.net/2440/21561.

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Copies of author's previously published articles inserted. Bibliography: leaves 184-197. xxvi, 197 leaves, [5] leaves of plates : ill. (some col.) ; 30 cm. Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science, 1995

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Roberts, Christine. "Spatial relationships of vesicular-arbuscular mycorrhizae, soil fauna and soil nutrients in the juniper-sagebrush-grass communities of central Oregon /." 1994. http://hdl.handle.net/1957/10032.

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17

Phillips, Wendy S. "Drivers of arbuscular mycorrhizal fungal community composition in roots : hosts, neighbors, and environment." Thesis, 2012. http://hdl.handle.net/1957/34446.

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The vast majority of terrestrial plant species live in symbiosis with arbuscular mycorrhizal fungi (AMF). AMF and plants live in complex networks, with roots of individual plants hosting multiple AMF, and single AMF colonizing multiple plants concurrently. Through the exchange of resources, the two partners of this symbiosis can have great effects on each other, effects which can ripple through both communities. What determines the patterns of associations between the partners is still largely unknown. In this dissertation, I examine a variety of factors, and in particular host identity, that could drive the community composition of AMF in roots. I began by surveying the diversity of AMF in roots of 12 plant species at a remnant bunchgrass prairie in Oregon, U.S.A. (Chapter 2). To do that, I first designed new primers for use in polymerase chain reaction (PCR) to specifically amplify DNA from all Glomeromycota species. Using those primers, I found 36 distinct AMF phylogenetic groups, or operational taxonomic units (OTUs) in the roots from the prairie. The proportion of OTUs in the basal order Archaeosporales was greater than in many other environmental surveys. I also conducted an in silico analysis to predict how effectively previously published primers would detect the whole diversity of OTUs I detected. I then assayed AMF community composition in the roots of 50 plants from nine plant species (Chapter 3). To do that, I designed primers specific to 18 of the OTUs detected in the initial field survey and used them to test for the presence of each OTU in the roots individual plants. I used that data to test if AMF community composition in individual roots correlated with host identity, spatial distribution, or soil characteristics. I found host identity was associated with both the richness and the structure of root AMF communities, while spatial distribution and soil characteristics were not. Finally, I performed an experimental test of the effect of host identity and community context on AMF community assembly (Chapter 4). I grew plants from four native perennial plant species, including two common and two federally endangered plants, either individually or in a community of four plants (with one plant of each species). I analyzed the AMF community composition in the roots of all plants after 12 weeks of growth with exposure to a uniform mix of field soil as inoculum. I found that host species identity affected root AMF richness and community composition, and community context affected AMF richness. Only one of the endangered species was highly colonized by AMF, and I did not detect unique AMF communities associated with it. This dissertation provides information on the diversity of AMF at a remnant bunchgrass prairie, an ecosystem which has been the subject of very few studies of AMF. Although a complex mix of factors interact to determine AMF community composition in roots, this work provides strong evidence that host identity plays a major role in that process. Graduation date: 2013

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Gouveia, Estevam Manuel Rodriques. "Effects of arbuscular mycorrhiza on plant growth of four ornamental annuals (Dianthus chinensis x barbatus, Impatiens wallerana, Petunia x hybrida and Viola x wittrockiana) commonly grown in South Africa." Diss., 2016. http://hdl.handle.net/10500/22032.

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Commercial AM fungi isolates, Rhizophagus clarus, Gigaspora gigantea, Funneliformis mosseae, Claroideoglomus etunicatum and Paraglomus occulum were tested on four seasonal ornamentals, Dianthus chinensis x barbatus, Impatiens wallerana, Petunia x hybrid and Viola x wittrockiana planted in peat-base medium. The experiment was conducted in a glasshouse with three replicates in a completely randomised design. Various vegetative (height, width, length, number of leaves, leaf area and dry biomass) and reproductive (number of flowers and buds) plant parts were measured in the course of three months. AM fungi was found to increase seedling growth and reduced seedling mortality rate of all the plants studied. Inoculated plants produced more leaves (16-33%) and grew taller (12-28%). Dry biomass of inoculated Dianthus, Impatiens and Viola plants were significantly increased by 25-53%. All plants under low colonisation rates displayed mycotrophic qualities and net growth output thereof were found to be similar to plants with equal or higher colonisation rate. Mortality were less frequent in inoculated plants and they were also less susceptible to transplant shock. Agriculture, Animal Health and Human Ecology M. Sc. (Ornamental Horticulture)

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Dissertations / Theses on the topic 'Vesicular-arbuscular mycorrhizas. Plants Fungicides'

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