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As árvores que se desenvolvem nas cidades estão sujeitas a muitos fatores negativos, incluindo várias tensões envolvendo poluição, condições climáticas, falta de nutrientes e outras. Esses fatores afetam a associação entre ectomicorrízicos (ECM) e as raízes das plantas. Infelizmente, não existem muitos estudos sobre esse problema. Três espécies de fungos, Lactarius deliciosus, Russula parazurea, e Paxillus involutus, foram utilizadas para inocular, em condições de viveiro, mudas de Tilia tomentosa utilizando diferentes transportadores (transportadores à base de alginato e ágar). Na presente tese, examinamos as mudas de T. tomentosa com crescimento de 6 meses para entender como a interação entre os fungos da ECM e a planta foi afetada pelo pH ácido e alcalino que pode ocorrer em contextos urbanos. Foram avaliados parâmetros nutricionais e biométricos, como alongamento e diâmetro da parte aérea, biomassa, comprimento das raízes, teor de clorofila e nitrogênio total e fósforo. A colonização por ECM e a taxa de expansão micorrízica também foram determinadas. O alginato transportado provou ser um portador mais eficiente que o portador à base de ágar em termos de colonização por ECM e expansão micorrízica, mostrando níveis mais altos nas duas condições de pH. Além disso, o peso foliar fresco e o comprimento da raiz secundária também apresentaram níveis elevados em comparação com outros tratamentos no nível de pH ácido. Como tal, toda a análise remanescente relativa ao efeito dos três fungos ECM no desempenho das plantas apresentadas nesta tese refere-se ao material à base de alginato. Os resultados indicam que os fungos ECM selecionados podem ser ferramentas biotecnológicas benéficas no crescimento de T. tomentosa como uma árvore urbana, no entanto, nem todos os fungos têm o mesmo impacto benéfico em todos os parâmetros da planta. As plantas inoculadas com P. involutus revelaram maior biomassa radicular (fresca e seca) nas duas condições de pH, enquanto as plantas inoculadas com R. parazurea apresentaram maior biomassa foliar. L. deliciosus foi o único capaz de promover o alongamento da parte aérea da planta e isso só foi verificado em condições ácidas. Em relação ao diâmetro da parte aérea, apenas as mudas inoculadas com P. involutus. apresentaram valores mais altos e encontrados no pH alcalino. Em relação aos teores de nutrientes nas mudas, as diferenças foram observadas apenas para o fósforo, onde em condições ácidas o teor geral de P nas folhas e raízes é geralmente mais alto em todos os tratamentos inoculados. Quanto ao conteúdo de clorofila, também houve resultados diferentes com os três fungos. Plantas tratadas com R. parazurea, apresentaram valores mais altos no pH ácido, enquanto no pH alcalino P. involutus e R. parazurea apresentaram maiores valores. A colonização por fungos ECM e a taxa de expansão micorrízica foram maiores em todas as mudas inoculadas, porém em condições ácidas a colonização por P. involutus foi observada em maiores extensões. Este estudo corrobora ainda que os fungos ECM são um importante atributo ambiental e tem aplicações importantes no manejo florestal urbano. Esses resultados destacam a importância das associações entre as árvores e os fungos ECM, pois podem afetar o desempenho da planta em diferentes ambientes.
Trees developing in cities are subjected to many negative factors, including several stresses involving pollution, climate conditions, lack of nutrients and others. These factors affect the association between ectomycorrhizal (ECM) and plant roots. Unfortunately, there are not many studies concerning this problem. Three fungi species, Lactarius deliciosus, Russula parazurea, and Paxillus involutus, have been used to inoculate, in nursery conditions, Tilia tomentosa seedlings using different carriers (alginate and agar-based carriers). In the present thesis the seedlings of T. tomentosa with 6-month growth were examined to understand how the interaction between ECM fungi and the plant was affected by acidic and alkaline pH that may occur in urban contexts. Nutritional and biometric parameters, such as shoot elongation and diameter, biomass, root length, chlorophyll content, and total Nitrogen(N) and Phosphorus(P), were evaluated. ECM colonisation and mycorrhizal expansion rate were also determined. Alginate carried proved to be a more efficient carrier than the agar-based carrier in terms of ECM colonisation and mycorrhizal expansion, showing higher levels in both pH conditions. Moreover, foliar fresh weight and secondary root length also shown elevated levels compared to other treatments in acidic pH level. As such, all of the remaining analysis concerning the effect of the three ECM fungi on plant performance presented in this thesis refer to the alginate-based material. Results indicate that selected ECM fungi can be beneficial biotechnological tools in growth of T. tomentosa as an urban tree, however not all the fungi have the same beneficial impact in all plant parameters. Plants inoculated with P. involutus revealed higher root biomass (fresh and dry) in both pH conditions whereas plants inoculated with R. parazurea, presented higher foliar biomass. L. deliciosus was the only able to promote plant shoot elongation and that was only verified in acidic conditions. Concerning shoot diameter, only the seedlings inoculated with P.involutus. showed higher values and that was found in alkaline pH. Concerning nutrient contents in the seedlings, differences were only seen for phosphorous where in acidic conditions the overall content in the leaves and roots were generally higher for all inoculated treatments. Regarding chlorophyll contents, there were also different outcomes with the three fungi. Plants treated with R. parazurea,. showed higher values in acid pH whereas in alkaline pH P. involutus and R. parazurea showed higher values. ECM colonisation and mycorrhizal expansion rate were higher in all inoculated seedlings, however in acidic conditions colonisation by P. involutus was observed at higher extents. This study further corroborates that ECM fungi is an important environmental attribute and has important applications in urban forest management. These results highlight the importance of the associations between ECM structures and trees as they can impact plant performance in different environments.
Trees developing in cities are subjected to many negative factors, including several stresses involving pollution, climate conditions, lack of nutrients and others. These factors affect the association between ectomycorrhizal (ECM) and plant roots. Unfortunately, there are not many studies concerning this problem. Three fungi species, Lactarius deliciosus, Russula parazurea, and Paxillus involutus, have been used to inoculate, in nursery conditions, Tilia tomentosa seedlings using different carriers (alginate and agar-based carriers). In the present thesis the seedlings of T. tomentosa with 6-month growth were examined to understand how the interaction between ECM fungi and the plant was affected by acidic and alkaline pH that may occur in urban contexts. Nutritional and biometric parameters, such as shoot elongation and diameter, biomass, root length, chlorophyll content, and total Nitrogen(N) and Phosphorus(P), were evaluated. ECM colonisation and mycorrhizal expansion rate were also determined. Alginate carried proved to be a more efficient carrier than the agar-based carrier in terms of ECM colonisation and mycorrhizal expansion, showing higher levels in both pH conditions. Moreover, foliar fresh weight and secondary root length also shown elevated levels compared to other treatments in acidic pH level. As such, all of the remaining analysis concerning the effect of the three ECM fungi on plant performance presented in this thesis refer to the alginate-based material. Results indicate that selected ECM fungi can be beneficial biotechnological tools in growth of T. tomentosa as an urban tree, however not all the fungi have the same beneficial impact in all plant parameters. Plants inoculated with P. involutus revealed higher root biomass (fresh and dry) in both pH conditions whereas plants inoculated with R. parazurea, presented higher foliar biomass. L. deliciosus was the only able to promote plant shoot elongation and that was only verified in acidic conditions. Concerning shoot diameter, only the seedlings inoculated with P.involutus. showed higher values and that was found in alkaline pH. Concerning nutrient contents in the seedlings, differences were only seen for phosphorous where in acidic conditions the overall content in the leaves and roots were generally higher for all inoculated treatments. Regarding chlorophyll contents, there were also different outcomes with the three fungi. Plants treated with R. parazurea,. showed higher values in acid pH whereas in alkaline pH P. involutus and R. parazurea showed higher values. ECM colonisation and mycorrhizal expansion rate were higher in all inoculated seedlings, however in acidic conditions colonisation by P. involutus was observed at higher extents. This study further corroborates that ECM fungi is an important environmental attribute and has important applications in urban forest management. These results highlight the importance of the associations between ECM structures and trees as they can impact plant performance in different environments.
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Palavras-chave
Ectomicorrizal Árvores urbanas Tilia tomentosa Aarriers Stress abiótico Ectomycorrhizal Urban trees Carriers Abiotic stress