The arbuscular mycorrhizal (AM) association results from a successful interaction between the genomes of the two symbiotic partners. In this context, the aim of my research was to better characterize the role of the late stage symbiosis-related pea genes PsSym36, PsSym33 and PsSym40 in the functional AM (i) by investigating the effect of mutations in the three genes on fungal and plant gene responses and (ii) by creating conditions for the localization of two of the genes, PsSym36 and PsSym40, on the pea genetic map for future map-based cloning. The expression of a subset of ten fungal and eight plant genes,previously reported to be activated during mycorrhiza development, was compared in Glomus intraradices-inoculated roots of wild type and Pssym36, Pssym33 and Pssym40 mutant pea plants. Most of the fungal genes were down-regulated in roots of the Pssym36 mutant where arbuscule formation is defective, and several were upregulated with more rapid fungal development in roots of the Pssym40 mutant. Microdissection of mycorrhizal PsSym40 roots corroborated preferential expression of the three G. intraradices genes SOD, DESAT and PEPISOM in arbuscule-containing cells. Inactivation of PsSym36 also resulted in down regulation of plant genes whilst mutation of the PsSym33 and PsSym40 genes affected plant gene responses in a more time-dependent way. Results thus indicate an implication of the investigated pea SYM genes in the modulation of plant and fungal molecular interactions linked to signaling, nutrient exchange or stress response regulation during AM symbiosis formation and functioning. Conditions for localization of the PsSym36 and PsSym40 genes on the pea genetic map were developed for their future map-based cloning. Based on the molecular markers obtained, it was possible to conclude that localization of the PsSym40 gene most likely resides outside the linkage groups I, II, III or V of the genetic map of pea.

No description available.

Stretches of forest along the Limpopo and Shashe Rivers have been classified as a unique forest type in the vegetation of South Africa and are considered as being "critically endangered" by the South African Biodiversity Institute. Roughly 400 hectares of this riverine forest area inside the western section of the Mapungubwe National Park (MNP), a UNESCO World Heritage site, were deforested and therefore degraded due to previous agricultural cultivation practices. Given the extent of forest degradation that has occurred, the restoration of this area by means of the re–vegetation of indigenous trees to its former composition is one of the objectives of the MNP's management plan. The successful establishment of tree seedlings, especially in semi–arid systems, is however presented with a wide range of constraints and limiting conditions, which often result in very high mortality rates during restoration projects. An experimental exclosure, as identified by South African National Parks (SANParks), was therefore fenced off inside the degraded old lands to act as a demonstration site for the restoration of indigenous trees. A pilot study conducted in 2006, involved the transplantation of selected indigenous tree species with the aim of evaluating suitable re–vegetation technologies. The research contained in this dissertation was also conducted inside the experimental exclosure, where recommendations derived from the pilot study were evaluated, including the assessment of new re–vegetation technologies to enhance the establishment of the indigenous trees. This study was therefore a follow–up project which involved both field– and greenhouse trials. Seedlings of the following species were either transplanted into the experimental exclosure (field trial) or cultivated inside a controlled environment in the greenhouse at the North–West University: Acacia xanthophloea Benth. (fever tree), Berchemia discolor (Klotzsch) Hemsl. (brown–ivory), Combretum imberbe Wawra (leadwood), Faidherbia albida (Delile) A. Chev. (ana tree), Philenoptera violacea (Klotzsch) Schrire (apple–leaf), Salvadora australis Schweick. (narrow–leaved mustard tree) and Xanthocercis zambesiaca (Baker) Dumaz–le–Grand (nyala tree). During the follow–up study the effects of various enhancement treatments were tested regarding the survival, growth and physiological performance of seedlings in both the field– and greenhouse trials. The enhancement treatments consisted of the addition of compost and indigenous arbuscular mycorrhizal fungi (AMF). In addition, seedlings transplanted during the pilot study, which did not include enhancement treatments, were also monitored for establishment and growth. The potential use of established Acacia tortilis Hayne trees to facilitate growth and establishment and to act as "nursing plants", was also assessed. In addition, various pre–sowing treatments were also applied to seeds of selected tree species in the greenhouse to assess the germination rate. The survivorship and growth of seedlings in both the field– and greenhouse trial were determined by using three growth parameters, namely "stem diameter at the base", "stem diameter 30 cm from the base", and "height of the tree in its natural growth form". Chlorophyll fluorescence induction (JIP test) was measured on seedlings in both trials, using the multi–parametric expression, namely performance index (PIABS), as a measure of the overall vitality of the plants of each species–treatment combination. Physical and chemical analyses were carried out on the soil inside the experimental exclosure. Basic descriptive statistics were used to analyse seedling survival and germination rates, and a two–way analysis of variance (ANOVA) was used to determine the statistical significant effects of the various enhancement treatments on diameter growth in each species (p < 0.05). Fluorescence data were processed using the Biolyzer software and significant effects in each species were determined using the Student's t–test (p < 0.05). Multivariate data ordinations using the CANOCO package were used to determine the differences in soil types inside the experimental exclosure. Moisture stress due to transplantation shock, competition with dense grass cover and herbivory, resulted in an overall 55.8% seedling survival rate and negative stem diameter growth for transplanted seedlings in the field. In comparison, seedlings cultivated in the greenhouse had much higher survival rates and showed positive stem diameter growth. Most species in the greenhouse showed higher growth rates and significantly higher vitality values when planted with enhancement treatments. The responses of transplanted seedlings to the enhancement treatments were very species–specific in the field trials. Based on these results, it was concluded that the enhancement treatments were beneficial with regard to the establishment and growth of most of the species. The beneficial effect was however cancelled out by the various abiotic and biotic factors encountered in the natural environment. Seedlings transplanted in the understory of established pioneer A. tortilis trees had much lower survival rates as the extensive root system of A. tortilis most likely out–competed the transplanted seedlings for moisture and nutrients. Many seedlings were also predated by insects or small mammals which reduced the growing potential. The germination trials recorded the highest germination rates for most species when germinated in the compost–containing treatments. These trials also indicated that all of the investigated species showed higher survival rates when pre–sowing treatments, such as soaking, mechanical scarification and removing the seed from fruit, were applied. Various recommendations emphasising long–term monitoring, proper maintenance and after–care of future restoration efforts are made. These include experimental layout of exclosure plots and pretransplantation treatments of seedlings while cultivated in the nursery. During this study, the experimental exclosure was also used as a demonstration site for training and capacity building for SANParks personnel and students from academic institutions. / Thesis (M.Sc. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

Stretches of forest along the Limpopo and Shashe Rivers have been classified as a unique forest type in the vegetation of South Africa and are considered as being "critically endangered" by the South African Biodiversity Institute. Roughly 400 hectares of this riverine forest area inside the western section of the Mapungubwe National Park (MNP), a UNESCO World Heritage site, were deforested and therefore degraded due to previous agricultural cultivation practices. Given the extent of forest degradation that has occurred, the restoration of this area by means of the re–vegetation of indigenous trees to its former composition is one of the objectives of the MNP's management plan. The successful establishment of tree seedlings, especially in semi–arid systems, is however presented with a wide range of constraints and limiting conditions, which often result in very high mortality rates during restoration projects. An experimental exclosure, as identified by South African National Parks (SANParks), was therefore fenced off inside the degraded old lands to act as a demonstration site for the restoration of indigenous trees. A pilot study conducted in 2006, involved the transplantation of selected indigenous tree species with the aim of evaluating suitable re–vegetation technologies. The research contained in this dissertation was also conducted inside the experimental exclosure, where recommendations derived from the pilot study were evaluated, including the assessment of new re–vegetation technologies to enhance the establishment of the indigenous trees. This study was therefore a follow–up project which involved both field– and greenhouse trials. Seedlings of the following species were either transplanted into the experimental exclosure (field trial) or cultivated inside a controlled environment in the greenhouse at the North–West University: Acacia xanthophloea Benth. (fever tree), Berchemia discolor (Klotzsch) Hemsl. (brown–ivory), Combretum imberbe Wawra (leadwood), Faidherbia albida (Delile) A. Chev. (ana tree), Philenoptera violacea (Klotzsch) Schrire (apple–leaf), Salvadora australis Schweick. (narrow–leaved mustard tree) and Xanthocercis zambesiaca (Baker) Dumaz–le–Grand (nyala tree). During the follow–up study the effects of various enhancement treatments were tested regarding the survival, growth and physiological performance of seedlings in both the field– and greenhouse trials. The enhancement treatments consisted of the addition of compost and indigenous arbuscular mycorrhizal fungi (AMF). In addition, seedlings transplanted during the pilot study, which did not include enhancement treatments, were also monitored for establishment and growth. The potential use of established Acacia tortilis Hayne trees to facilitate growth and establishment and to act as "nursing plants", was also assessed. In addition, various pre–sowing treatments were also applied to seeds of selected tree species in the greenhouse to assess the germination rate. The survivorship and growth of seedlings in both the field– and greenhouse trial were determined by using three growth parameters, namely "stem diameter at the base", "stem diameter 30 cm from the base", and "height of the tree in its natural growth form". Chlorophyll fluorescence induction (JIP test) was measured on seedlings in both trials, using the multi–parametric expression, namely performance index (PIABS), as a measure of the overall vitality of the plants of each species–treatment combination. Physical and chemical analyses were carried out on the soil inside the experimental exclosure. Basic descriptive statistics were used to analyse seedling survival and germination rates, and a two–way analysis of variance (ANOVA) was used to determine the statistical significant effects of the various enhancement treatments on diameter growth in each species (p < 0.05). Fluorescence data were processed using the Biolyzer software and significant effects in each species were determined using the Student's t–test (p < 0.05). Multivariate data ordinations using the CANOCO package were used to determine the differences in soil types inside the experimental exclosure. Moisture stress due to transplantation shock, competition with dense grass cover and herbivory, resulted in an overall 55.8% seedling survival rate and negative stem diameter growth for transplanted seedlings in the field. In comparison, seedlings cultivated in the greenhouse had much higher survival rates and showed positive stem diameter growth. Most species in the greenhouse showed higher growth rates and significantly higher vitality values when planted with enhancement treatments. The responses of transplanted seedlings to the enhancement treatments were very species–specific in the field trials. Based on these results, it was concluded that the enhancement treatments were beneficial with regard to the establishment and growth of most of the species. The beneficial effect was however cancelled out by the various abiotic and biotic factors encountered in the natural environment. Seedlings transplanted in the understory of established pioneer A. tortilis trees had much lower survival rates as the extensive root system of A. tortilis most likely out–competed the transplanted seedlings for moisture and nutrients. Many seedlings were also predated by insects or small mammals which reduced the growing potential. The germination trials recorded the highest germination rates for most species when germinated in the compost–containing treatments. These trials also indicated that all of the investigated species showed higher survival rates when pre–sowing treatments, such as soaking, mechanical scarification and removing the seed from fruit, were applied. Various recommendations emphasising long–term monitoring, proper maintenance and after–care of future restoration efforts are made. These include experimental layout of exclosure plots and pretransplantation treatments of seedlings while cultivated in the nursery. During this study, the experimental exclosure was also used as a demonstration site for training and capacity building for SANParks personnel and students from academic institutions. / Thesis (M.Sc. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

Orientador: Ana Maria Rodrigues Cassiolato / Banca: Luiz Antonio Graciolli / Banca: Gilberto Colodro / Resumo: O solo é um meio que engloba diferentes substâncias químicas e colóides e uma alta diversidade biológica. Estes componentes apresentam íntima relação funcional para sustentabilidade dos ecossistemas e, sua degradação, geralmente causada pela ação antrópica, acarreta um grande prejuízos ambientais e socioeconômicos para as gerações atuais e um enorme risco para as gerações futuras. Para reverter um processo como este, são necessárias intervenções por meio de estratégias como a revegetação. O objetivo do trabalho foi avaliar crescimento e colonização micorrízica do pinhão manso em solo decaptado que recebeu inoculo de fungos micorrizicos arbusculares, hidrogel e materiais orgânicos. O experimento foi conduzido de maio de 2008 a maio 2009, na Fazenda de Ensino, Pesquisa e Extensão (FEPE) da UNESP - Universidade Estadual Paulista, Campus de Ilha Solteira, no município de Selvíria-MS. O delineamento experimental foi o em blocos casualizado, em esquema fatorial 4x2x2, ou seja, 3 tratamentos com material orgânico (aguapé, composto e aguapé+composto), 2 tratamentos com hidrogel (com e sem adição) e 2 tratamentos de inoculação (com e sem inoculação) empregando solo proveniente de uma área preservada de cerrado como fonte de microrganimos, incluíndo fungos micorrízicos arbusculares, com 4 repetições e 5 plantas por tratamentos. O composto foi preparado com materiais de poda e esterco de bovino. Avaliou-se: o crescimento das plantas em 7 épocas diferentes, a caracterização química e número de esporos em 4 épocas, além da porcentagem de colonização micorrízica, presença de flores, número de ramos e de folhas e peso fresco e seco da parte aérea. O tratamento com hidrogel não mostrou interferência no crescimento de plantas, mas, assim como o solo-inóculo, aumentou a esporulação, a colonização micorrízica e a produção de matéria seca... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The soil is a medium that contain different chemical substances and colloids and a high biological diversity. These components have functional relationship on the sustainability of ecosystems and their degradation, usually caused by human action, which causes great socio-economic damage to the present generations and an enormous risk for the future generations. To reverse such process, action is needed using strategies, such as, revegetation. The objective of this study was to evaluate the growth and mycorrhiza colonization of Jatropha on decapitated soil that received organic materials and hydrogel. The experiment was conducted from May 2008 to May 2009, the Farm Education, Research and Extension (FEPE), UNESP - Univ. Estadual Paulista, Ilha Solteira Campus, located at Selvíria city-MS, Brazil. The experimental design was randomized blocks in factorial scheme 3x2x2, i.e., 3 treatments with organic materials (water hyacinth, compost and water hyacinth + compost), 2 hydrogel treatments (with and without addition) and 2 inoculations treatments (with and without inoculation) using natural soil from a preserved 'cerrado' area as a source of microorganisms, including mycorrhizal fungi, with 4 replications and 5 plants per each. The compound was prepared with materials pruning and cow dung. The growth of plants in 7 different times, the chemical characterization and number of spores in 4 times, and the percentage of mycorrhizal colonization, presence of flowers, branches and leaves and fresh and dry weight of air part was evaluated. Treatment with hydrogel showed no interference with the growth of plants; however, as well as the soilinoculum, they increased sporulation, root colonization and production of dry matter. The organic materials treatments positively altered the condition of the ground, plant growth, mycorrhizal colonization and sporulation; the improved performances... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:29:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-15Bitstream added on 2014-06-13T20:39:15Z : No. of bitstreams: 1 santos_aa_me_ilha.pdf: 676511 bytes, checksum: f49f6d1a9f6dfba6539f793f9e93426c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O solo é um meio que engloba diferentes substâncias químicas e colóides e uma alta diversidade biológica. Estes componentes apresentam íntima relação funcional para sustentabilidade dos ecossistemas e, sua degradação, geralmente causada pela ação antrópica, acarreta um grande prejuízos ambientais e socioeconômicos para as gerações atuais e um enorme risco para as gerações futuras. Para reverter um processo como este, são necessárias intervenções por meio de estratégias como a revegetação. O objetivo do trabalho foi avaliar crescimento e colonização micorrízica do pinhão manso em solo decaptado que recebeu inoculo de fungos micorrizicos arbusculares, hidrogel e materiais orgânicos. O experimento foi conduzido de maio de 2008 a maio 2009, na Fazenda de Ensino, Pesquisa e Extensão (FEPE) da UNESP – Universidade Estadual Paulista, Campus de Ilha Solteira, no município de Selvíria-MS. O delineamento experimental foi o em blocos casualizado, em esquema fatorial 4x2x2, ou seja, 3 tratamentos com material orgânico (aguapé, composto e aguapé+composto), 2 tratamentos com hidrogel (com e sem adição) e 2 tratamentos de inoculação (com e sem inoculação) empregando solo proveniente de uma área preservada de cerrado como fonte de microrganimos, incluíndo fungos micorrízicos arbusculares, com 4 repetições e 5 plantas por tratamentos. O composto foi preparado com materiais de poda e esterco de bovino. Avaliou-se: o crescimento das plantas em 7 épocas diferentes, a caracterização química e número de esporos em 4 épocas, além da porcentagem de colonização micorrízica, presença de flores, número de ramos e de folhas e peso fresco e seco da parte aérea. O tratamento com hidrogel não mostrou interferência no crescimento de plantas, mas, assim como o solo-inóculo, aumentou a esporulação, a colonização micorrízica e a produção de matéria seca... / The soil is a medium that contain different chemical substances and colloids and a high biological diversity. These components have functional relationship on the sustainability of ecosystems and their degradation, usually caused by human action, which causes great socio-economic damage to the present generations and an enormous risk for the future generations. To reverse such process, action is needed using strategies, such as, revegetation. The objective of this study was to evaluate the growth and mycorrhiza colonization of Jatropha on decapitated soil that received organic materials and hydrogel. The experiment was conducted from May 2008 to May 2009, the Farm Education, Research and Extension (FEPE), UNESP - Univ. Estadual Paulista, Ilha Solteira Campus, located at Selvíria city-MS, Brazil. The experimental design was randomized blocks in factorial scheme 3x2x2, i.e., 3 treatments with organic materials (water hyacinth, compost and water hyacinth + compost), 2 hydrogel treatments (with and without addition) and 2 inoculations treatments (with and without inoculation) using natural soil from a preserved ‘cerrado’ area as a source of microorganisms, including mycorrhizal fungi, with 4 replications and 5 plants per each. The compound was prepared with materials pruning and cow dung. The growth of plants in 7 different times, the chemical characterization and number of spores in 4 times, and the percentage of mycorrhizal colonization, presence of flowers, branches and leaves and fresh and dry weight of air part was evaluated. Treatment with hydrogel showed no interference with the growth of plants; however, as well as the soilinoculum, they increased sporulation, root colonization and production of dry matter. The organic materials treatments positively altered the condition of the ground, plant growth, mycorrhizal colonization and sporulation; the improved performances... (Complete abstract click electronic access below)

Orientador: Sylvio Luis Honorio / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-08T08:41:42Z (GMT). No. of bitstreams: 1 Portugal_EdilbertoPrinci_D.pdf: 3108115 bytes, checksum: 834974ae808b2dc8cae3ca812f9976ba (MD5) Previous issue date: 2006 / Resumo: A Stevia rebaudiana, um arbusto que tem na produção de esteviosídeos seu principal produto de interesse, foi objeto deste trabalho. Considerando sua cadeia produtiva, existem lacunas que necessitam pesquisas, tanto no aspecto agronômico, como o emprego de espécies fúngicas micorrízicas, quanto procedimentos pós-colheita, dos quais a secagem é um dos fatores. O presente trabalho teve como objetivos, identificar uma espécie de fungo micorrízico arbuscular eficiente e sua relação com o desenvolvimento e concentração de esteviosídeos em plantas de estévia, cultivadas em campo, hidroponia e aeroponia, selecionar substrato adequado para o desenvolvimento da colonização micorrízica, avaliar sistemas de secagem no teor de esteviosídeos e determinar as isotermas de sorção da estévia. Para seleção de fungo micorrízico foram testadas sete espécies, sendo cinco de um banco de culturas e duas isoladas da própria cultura da estévia. O ensaio foi conduzido em casa de vegetação em vasos com solo esterilizado e cinco repetições. Foram determinados a massa seca total da parte aérea e de folhas, teor e quantidade acumulada de esteviosídeos nas folhas e colonização micorrízica. Para seleção de substratos, foram testados nove produtos comerciais, utilizando-se como planta indicadora uma gramínea (Brachiaria humidicola) e como parâmetro avaliado a taxa de colonização fúngica no sistema radicular. Plantas de estévia inoculadas ou não com o fungo micorrízico Glomus intraradices foram cultivadas em três sistemas distintos, campo, aeroponia e hidroponia. Foram realizadas três colheitas em épocas distintas e determinada a massa da matéria seca total da parte aérea e de folhas, teor e acúmulo de esteviosídeos nas folhas e colonização micorrízica. Foram testados três processos de secagem, ao sol, secador a gás e estufa elétrica com circulação forçada de ar, à temperatura de 45oC. Os processos foram avaliados em função do teor de esteviosídeos nas folhas. A determinação da umidade de equilíbrio nas folhas de estévia foi realizada nas temperaturas de 30 e 45oC e, as isotermas de sorção foram tratadas com os modelos matemáticos de BET, BET linear, Peleg, GAB, Halsey, Langmuir, Oswin, Henderson e Chung e Pfost. A espécie Glomus intraradices foi a mais eficiente para o desenvolvimento da estévia e acumulação de esteviosídeos. O substrato Rendmax Citrus sem adubação propiciou as melhores condições para a colonização micorrízica nas raízes da gramínea. Dentre os sistemas de cultivo estudados a hidroponia mostrou-se o menos eficiente para o cultivo de estévia. Em aeroponia obteve-se maior produtividade em termos de matéria seca da parte aérea, enquanto no campo maior quantidade acumulada de esteviosídeos. Não se observou diferença entre a secagem na estufa e no secador para qualquer das épocas de colheita. O teor de esteviosídeos nas folhas de plantas secadas ao sol foi sempre inferior, com perda de até 20% em relação aos outros dois sistemas. Os modelos que apresentaram melhor ajuste, nas temperaturas de 30 e 45oC, foram GAB e HALSEY. O modelo BET LINEAR também mostrou bom ajuste, mas somente para a temperatura de 45oC / Abstract: Stevia rebaudiana, a shrub mostly interesting for its production of steviosides, was the object of this work. In regard to its productive chain, further researches must be done, not only in agronomical aspects, but also in the utilization of mycorrhizal fungal species, as well as in the post-harvest processes, namely the drying one. The present work aimed at the identification of an efficient arbuscular mycorrhizal fungal species and its influence in the development and concentration of steviosides in stevia plants grown in hydroponic and aeroponic systems; to select an adequate substrate for the development of mycorrhizal fungi; to evaluate drying systems in steviosides rates and to determine stevia?s isotherms of sorption. For the mycorrhizal fungi selection seven species were tested, five from a germplasm bank and two were isolated from their own stevia culture. Five assays in pots with sterilized soil were carried out in a greenhouse. The total dry mass of the aerial parts and of the leaves, the rate and accumulated quantity of steviosides in the leaves as well as the mycorrhizal colonization were determined. Nine commercial substrates were tested for the rate of colonization of the root system of an indicating gramineous plant (Brachiaria humidicola). Stevia plants that were inoculated (or not) with the mycorrhizal fungus Glomus intraradices were cultivated in three different growing systems, field, aeroponic and hydroponic. Three harvests were carried out in different periods and the total dry mass of the branch and leaves sections, contents and accumulated steviosides in the leaves and mycorrhizal colonization were determined. Three processes for drying leaves were tested: by sunlight, gas dryer and electrical stove with forced air circulation, at 45oC. The processes were evaluated in relation to the steviosides rate of the leaves. The equilibrium moisture content for stevia leaves was done at 30oC and 45oC, while the isotherms of sorption were tested for the best fit by mathematical models of BET, BET linear, Peleg, Gab, Halsey, Langmuir, Oswin, Henderson and Chung and Pfost. The Glomus intraradices species was the most efficient for the stevia development and accumulation of steviosides. The Rendmax Citrus substrate without manure rendered the best conditions for the mycorrhizal colonization in the gramineous roots. Among the growing systems studied, hydroponics turned out to be the least efficient for stevia cultivation. Aeroponics brought the highest production in terms of dry mass from the aerial parts, while in the field a larger accumulated quantity of steviosides was obtained. No difference was observed between the stove and gas drying processes at any of the harvesting periods. The steviosides rate from the leaves dried by sunlight was always inferior, coming to a loss of 20% in relation to the others. The best fit models were GAB and HALSEY. The BET LINEAR fitted by 45ºC / Doutorado / Tecnologia Pós-Colheita / Doutor em Engenharia Agrícola

Symbiosis with endomycorrhiza is found in a majority of plant-fungal symbioses. The symbiosis helps with various stressors such as drought and malnutrition. This study looked at how four different field, meadow and brook plants - Centaurea cyanus, Galium verum, Viscaria vulgaris and Veronica beccabunga - are affected by mycorrhiza and fertilizer treatment. The hypotheses tested whether mycorrhiza occurrence and fertilizer treatment affected the total number and number of mature and open flowers in C. cyanus as well as whether mycorrhiza occurrence and fertilizer treatment affected the aboveground biomass and the underground biomass of the four plant species. The study looked at 160 plants and a total of 40 plants of each species were planted. Per species, there were 10 control plants, 10 pots with mycorrhiza and 10 pots with fertilizer as well as 10 pots with both mycorrhiza and fertilizer. The pot arrangement was randomized. Mycorrhizal fungi were collected together with plant roots from different grass and forest habitats. The fertilizer treatment was applied once a week and lasted for six weeks. Two-way ANOVA was used in the analyses of the number of flowers in C. cyanus and three-way ANOVA was used in the analyses of aboveground and underground biomass. Fertilizer treatment had statistically significant effects on both the total number of flowers and the number of mature and open flowers. Fertilizer treatment also increased the aboveground of the selected species as well as the underground biomass of C. cyanus. The underground biomass of the other species decreased. However, the study could not find any significant effect of mycorrhiza treatment nor any significant interaction between mycorrhiza treatment and fertilizer treatment. The study did not test whether or how much of the mycorrhiza colonization was successful and the nonsignificant result may be due to several reasons. More research is needed to confirm the results in this study. / Symbios med endomykorrhiza återfinns hos en majoritet av växt-svampsymbioser. Symbiosen hjälper vid olika typer av stress såsom torka och näringsbrist. Denna studie tittade på hur fyra olika åker-, ängs- och bäckväxter - Centaurea cyanus, Galium verum, Viscaria vulgaris och Veronica beccabunga - påverkas av mykorrhiza och gödsling. Hypoteserna testade om mykorrhizaförekomst och gödsling påverkar det totala antalet och antalet utslagna blommor hos C. cyanus samt ovanjordsbiomassan och underjordsbiomassan hos de fyra växterna. Undersökningen tittade på 160 plantor och totalt planterades 40 plantor av varje art. Per art fanns 10 kontrollplantor, 10 krukor med mykorrhiza och 10 krukor med gödsling samt 10 krukor med både mykorrhiza och gödsling. Krukorna planterades ut slumpmässigt. Mykorrhizasvampar samlades in tillsammans med växtrötter från olika gräs- och skogshabitat. Kvävebehandlingen skedde en gång i veckan och varade i sex veckor. Två-vägs-ANOVA användes vid analys av antal blommor hos C. cyanus och tre-vägs-ANOVA användes vid analys av ovanjords- och underjordsbiomassa. Kvävebehandling kunde signifikant visas öka både det totala antalet blommor och antalet utslagna blommor. Kvävebehandling ökade även ovanjordsbiomassan hos de utvalda arterna samt underjordsbiomassan hos C. cyanus. Underjordsbiomassan minskade hos de andra arterna. Studien kunde emellertid inte hitta någon signifikant effekt av mykorrhizabehandling och inte heller någon signifikant interaktion mellan mykorrhizabehandling och kvävebehandling. I studien testades inte om eller hur mycket av mykorrhizakoloniseringen var framgångsrik och det icke-signifikanta resultatet kan ha haft flera orsaker. Mer forskning behövs för att bekräfta resultaten i denna studie.

La symbiose mycorhizienne à arbuscules, dont l’apparition est conjointe à celle des plantes terrestres il y a 460 millions d’années, est une association mutualiste à bénéfices réciproques qui s’instaure entre la plupart des plantes terrestres, y compris celles cultivées, et des microorganismes ubiquitaires du sol que sont les champignons mycorhiziens à arbuscules (CMA, phylum des Glomeromycota). Lors cette symbiose, le fort potentiel d’amélioration de la nutrition minérale des plantes, et donc de la production végétale, est un atout dans le contexte mondial actuel d’augmentation de la demande de la production agricole. Afin d’optimiser les services écosystémiques des CMA dans les écosystèmes et en particulier les agroécosystèmes, la maîtrise de cette symbiose en ingénierie écologique nécessite la compréhension des mécanismes complexes qui régissent la dynamique de cette symbiose dans ces écosystèmes. Pour cela, nous avons étudié la diversité des communautés et des populations de CMA dans les agroécosystèmes à différentes échelles spatiales et sous l’influence de différentes pratiques culturales par des techniques d’empreintes moléculaires: séquençage haut-débit et polymorphisme de longueur de fragments de restriction. Les résultats obtenus montrent que la structuration de la diversité des CMA est influencée par le type d’usage de sol (prairie vs. culture), les pratiques culturales (retournement du sol, fertilisation et système de culture) ainsi que par les facteurs abiotiques (e.g. pH du sol). En conclusion, ces différents facteurs sont à prendre en compte dans l’optimisation des services écosystémiques des CMA. / The arbuscular mycorrhizal symbiosis, which appeared at the same time as land plants, 460 million years ago, is a mutualistic beneficial association between most land plants, including those cultivated, and arbuscular mycorrhizal fungi (AMF). AMF, from the Glomeromycota phylum, are widespread soil microorganisms needing a photosynthetic host to complete their life cycle (obligate symbionts). The great potential of plant mineral nutrition improvement and crop production increased during this symbiosis, make AMF an asset in the context of an increase in the demand of world food crop production. The control of that symbiosis by ecology engineering in order to improve ecosystem services, especially in agroecosystems, needs to better understand the mechanisms regulating its dynamic. Therefore, we studied community and population diversity of AMF under influences of different agricultural practices at several spatial scales using genetic fingerprinting methods: high-throughput sequencing and restriction fragment length polymorphism. Results show that AMF diversity is structured by land use type (grassland vs. arable fields), cultural practices (soil disturbance, fertilizations, culturing systems) as well as environmental factors (e.g. soil pH). In conclusion, those different factors have to taken in account in AMF ecosystemic service managing.

Abstract Most plants form symbiotic associations with various fungi in natural ecosystems. Traditionally, many of these associations are viewed as mutually beneficial, but recent studies show that symbiotic interactions can be complex and labile. I studied the variability of interactions between grasses and fungi, using root-associated fungi and foliar endophytes in grasses as study systems. First, I studied experimentally how root-associated fungi colonize their host grasses in different natural and artificial conditions. I then investigated experimentally how foliar endophytes affect their host grasses, and whether the endophyte contributes to the host’s adaptation to local and/or foreign habitats. Finally, I reviewed the current use of foliar endophytes in agriculture, with a particular focus on Europe, and critically considered their potential for practices beyond agriculture. I found root fungi to be common, but different types of root fungi had contrasting colonization patterns in natural environments. However, I found that grasses lose almost all of their root fungi in controlled and more favourable conditions, indicating that the associations are fairly loose and conditional to environmental context. My results also showed that foliar endophytes affected the host’s performance in varying ways, depending on plant origin and experimental country, indicating that the associations were context dependent and could represent conditional mutualism. I also found that endophytes contribute to plant adaptation only weakly, but that the grasses were clearly locally adapted to their sites of origin, especially in regard to reproduction. However, the grasses of subalpine origin performed well vegetatively also in Northern Finland, suggesting that they may have high adaptive potential under changing climates. The literary review showed that foliar endophytes are successfully used in agriculture, e.g. in the USA and New Zealand, and that they possess the potential for several practical applications. However, the intentional use of endophyte-enhanced grasses is non-existent in Europe, although many European grass cultivars have great potential for improvement via endophytes. Taken together, these results show that plant–fungal interactions are highly variable along sites, environmental contexts and origins of the symbiotum, making predictions for these interactions difficult. / Tiivistelmä Luonnollisissa ekosysteemeissä melkein kaikilla kasveilla on symbionttisia sienikumppaneita. Perinteisesti monien näiden vuorovaikutusten on oletettu olevan molemmille hyödyllisiä, mutta viimeaikaiset tutkimukset osoittavat symbionttisten yhteyksien olevan vaihtelevia. Väitöskirjassani tutkin tätä heinien ja sienien välisten yhteyksien vaihtelevuutta, käyttäen heinissä esiintyviä juurisieniä ja lehtiendofyyttejä tutkimuskohteinani. Ensiksi tutkin kokeellisesti, kuinka juurisienet kolonisoivat heiniä erilaisissa luonnon- ja kasvihuoneolosuhteissa. Seuraavaksi tutkin kokeellisesti, kuinka lehtiendofyytit vaikuttivat heinien menestymiseen ja edesauttoivatko endofyytit heinien sopeutumista paikallisiin ja/tai vieraisiin elinympäristöihin. Viimeiseksi selvitin kirjallisuuskatsauksen avulla, kuinka lehtiendofyyttejä hyödynnetään maataloudessa ja arvioin endofyyttien potentiaalista käyttöarvoa maatalouden ulkopuolella, erityisesti keskittyen niiden hyödyntämiseen Euroopassa. Tutkimukseni osoitti, että heinien juurisienet ovat yleisiä, mutta niiden keskinäiset runsaussuhteet vaihtelivat luonnollisissa ympäristöissä. Kasvihuoneolosuhteissa heinät kuitenkin menettivät juurisienensä, viitaten siihen, että kyseinen yhteys on melko löyhä ja riippuvainen ympäristöstä. Tutkimukseni osoitti myös, että lehtiendofyytit vaikuttivat heinien menestykseen vaihtelevasti riippuen heinien alkuperästä sekä koemaasta, viitaten siihen, että nämä yhteydet ovat niin ikään olosuhteista riippuvaisia. Endofyytti vaikutti vain heikosti heinien sopeutumiseen, mutta heinät olivat selkeästi paikallisesti sopeutuneita niiden alkuperäisiin elinympäristöihin, erityisesti heinien lisääntymisen suhteen. Alppien heinät kuitenkin menestyivät vegetatiivisesti myös Pohjois-Lapissa, mikä viittaa siihen, että näillä heinillä saattaa olla korkea sopeutumispotentiaali muuttuvissa olosuhteissa. Kirjallisuuskatsaukseni osoitti, että lehtiendofyyttejä käytetään menestyksekkäästi mm. USA:n ja Uudessa-Seelannin maataloudessa. Euroopassa niiden käyttö on kuitenkin lähes olematonta, vaikka endofyyteillä voisi olla monia käyttömahdollisuuksia, sekä maataloudessa että ympäristön hoidossa. Kaiken kaikkiaan tutkimukseni osoittavat, että heinien ja sienten väliset vuorovaikutukset ovat hyvin vaihtelevia riippuen ympäristöstä ja heinien alkuperästä, minkä vuoksi näiden sienien vaikutuksia heiniin on vaikea ennustaa.