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- Bioremediation on anthropogenic affected areas: Ectomycorrhizal and plant growth bacteria as promoters of pine establishmentPublication . Franco, Albina R.; Sousa, Nadine R.; Ramos, Miguel A.; Castro, Paula M. L.The recovery of damaged areas due to inadequate farming policies and increased industrial sediment deposition, have contaminated not only soil and surrounding areas but also other natural resources. The potential use of disturbed sites for agriculture and forestry is jeopardised and their remediation is critical and expensive. The utilization of biotechnological tools, such as plant growth promoting bacteria (PGPB) and ectomycorrhizal fungi (ECM) could help remediation of such soils as they can be used as plant facilitators for land recovery. The aim of this study was to assess the potential of PGPB and ECM to enhance the growth of Pinus pinaster in antropogenic sediments and forest soil. Pine seedlings were inoculated with Suillus bovinus, Pisolithus tinctorius and Paxillus involutus, and co-inocualted with Bacillus spp. and Mesorhizobium spp. Plants were harvested after 6 month growth and parametric and nutritional data determined. Results show that P. involutus increased seedling growth(height) in industrial sediments soil, whereas in forest soil, plant performance was higher with S. bovinus. The effect of inoculation on the fungal communityin seedling roots and bacterial rhizosphere was also analysed by PCR-DGGE and differences arose between inoculated and uninoculated soil, indicating that PGPB and ECM may significantly influence the plant growth performance over a period of time. The study shows that PGPB and ECM fungi may be used as a biotechnology tool contributing to the successful plant establishment in disturbed environments.
- Succession dynamics of ectomycorrhizal fungi in inoculated Quercus rubra seedlings – a field studyPublication . Franco, Albina R.; Ramos, Miguel A.; Sousa, Nadine R.; Oliveira, Rui S.; Castro, Paula M. L.Selected ectomycorrhizal (ECM) fungi may have a beneficial effect on the establishment of nursery grown seedlings and may influence their survival on the first years. By increasing seedling capacity to capture nutrients, ECM fungi often contribute to a successful plant establishment. We investigated the performance of pre-inoculated Quercus rubra seedlings on a reforestation site and monitored ECM fungal persistence and succession dynamics between selected ECM fungi and native fungal community. Nursery grown Q. rubra seedlings inoculated with a mixture of ECM fungi (Cenococcum geophilum, Hebeloma crustuliniforme, H. mesophaeum, H. velutipes, Paxillus involutus, Scleroderma citrinum) and non-inoculated control oak seedlings, were transplanted to Serra da Cabreira in Northern Portugal. Two years after planting, the subsistence of the inoculated ECM fungi was assessed using ITS-DGGE. Results demonstrated that inoculation with selected ECM fungi at nursery stage promoted the establishment and improved the growth performance of out planted oak seedlings. C. geophilum was significantly associated with inoculated saplings but other ECM fungi species were also found. Moreover, ECM fungal communities of inoculated and non-inoculated samples are significantly different. Further monitoring is required to increase knowledge on the persistence of ECM fungal communities and their succession dynamics.
- Reforestation of burned stands: the effect of ectomycorrhizal fungi on Pinus pinaster establishmentPublication . Sousa, Nadine R.; Franco, Albina R.; Ramos, Miguel A.; Oliveira, Rui S.; Castro, Paula M. L.The area occupied by Pinus pinaster in Portugal is rapidly diminishing because of forest fires. Ectomycorrhizal fungi form obligate, mutually beneficial associations with P. pinaster which improve plant growth and resistance to adverse conditions. The aim of this work was to assess whether native ectomycorrhizal fungi could be a useful tool in the reforestation of burned areas. The work was conducted in a forest nursery greenhouse, where P. pinaster seedlings were inoculated with compatible ectomycorrhizal fungal isolates: Suillus bovinus, Pisolithus tinctorius, Rhizopogon roseolus, and a mixture of the three fungi, using burned and unburned forest soil as substrate. Inoculation significantly enhanced the growth of P. pinaster, with R. roseolus proving to be the most effective in burned soil, with an 8-fold increase in plant fresh weight. Overall, inoculation stimulated growth most in burned than in unburned soil. This study suggests that inoculation with selected ectomycorrhizal fungi in containerised nurseries can be an advantageous approach for the successful establishment of P. pinaster in burned soil. The obtained results point out to the interest of extending these studies into fire-impacted areas, using ectomycorrhizal fungi as a biological tool.
- Phytoremediation as a biotechnological tool for environmental restorationPublication . Marques, Ana P. G. C.; Rangel, António O. S. S.; Calheiros, Cristina S. C.; Oliveira, Rui S.; Franco, Albina R.; Vosatka, Miroslav; Dodd, John C.
- Potential of ectomycorrhizal fungi to degrade Trifluoroacetate, a recalcitrant compoundPublication . Franco, Albina R.; Castro, Paula M. L.
- Diverse Arbuscular Mycorrhizal Fungi (AMF) communities colonize plants inhabiting a constructed wetland for wastewater treatmentPublication . Calheiros, Cristina S. C.; Pereira, Sofia I. A.; Franco, Albina R.; Castro, Paula M. L.Constructed wetlands (CWs) are biological wastewater treatment systems that comprise several components where plants and associated organisms play an important role in water depuration. Microbial studies emphasize bacterial dynamics, whereas studies of arbuscular mycorrhizal fungi (AMF) are scarce and the functional role of AMF in aquatic and wetland plants is poorly understood. The aim of this study was to analyze the AMF communities colonizing the roots of Canna indica, Canna flaccida, and Watsonia borbonica inhabiting a CW treating wastewater of a tourism unit. The dynamics of the AMF communities were evaluated by Denaturing Gradient Gel Electrophoresis (DGGE) of 18S rRNA gene amplification products along cold (C) and hot (H) seasons for three consecutive years. DGGE profiles allowed the estimation of AMF species richness (S), and Shannon-Wienner (H) and Pielou (J) indexes, for the different plant species, showing differences between species and along the years. Excised bands from DGGE were analyzed and identified through sequencing for arbuscular mycorrhiza, revealing the presence of AMF strains closely related to Glomus sp., Rhizophagus sp. and Acaulospora sp. genera. Concomitant water quality analyses showed that the system was effective in organic and nutrient removal during the sampling period. Findings from this study suggest that AMF diversity found in the CW is influenced by the water constituents, season, and plant species.
- Tree breeding and mycorrhizal symbiosis as important tools in forestation processesPublication . Sousa, N. R.; Franco, A. R.; Ramos, Miguel A.; Oliveira, Rui S.; Castro, Paula M. L.
- The response of Betula pubescens to inoculation with an ectomycorrhizal fungus and a plant growth promoting bacterium is substrate-dependentPublication . Sousa, Nadine R.; Franco, Albina R.; Ramos, Miguel A.; Oliveira, Rui S.; Castro, Paula M. L.The combination of ectomycorrhizal (ECM) fungi and plant growth promoting bacteria (PGPB) has considerable potential in forestry. Here we report on the combined effects of PGPB Mesorhizobium sp. and the ECM fungus Paxillus involutus on the growth of Betula pubescens in two different substrates, a forest soil and an alkaline anthropogenic sediment. Growth, nutrient concentration and mycorrhizal formation of B. pubescens were determined at the end of the experiment and the fungal and bacterial communities were assessed by denaturing gradient gel electrophoresis. The combined effects of ECM and PGPB enhanced root and shoot growth most in the forest soil with Mesorhizobium appearing to stimulate mycorrhizal formation. However, in the alkaline sediment, an antagonistic interaction was detected between P. involutus and Mesorhizobium sp., with Mesorhizobium sp. alone stimulating growth. The significant interaction between the ECM and the PGBP across the two substrates is discussed.
- Assessment of mycorrhizal colonisation and soil nutrients in unmanaged fire-impacted soils from two target restoration sitesPublication . Dias, J. M.; Oliveira, R. S.; Franco, A. R.; Ritz, K.; Nunan, N.; Castro, P. M. L.The mycorrhizal colonisation of plants grown in unmanaged soils from two restoration sites with a fire history in Northern Portugal was evaluated from the perspective of supporting restoration programmes. To promote restoration of original tree stands, Quercus ilex L. and Pinus pinaster Ait. were used as target species on two sites, denoted Site 1 and 2 respectively. The aim of the study was to assess whether mycorrhizal propagules that survived fire episodes could serve as in situ inoculum sources, and to analyse the spatial distribution of soil nutrients and mycorrhizal parameters. In a laboratory bioassay, P. pinaster and Q. ilex seedlings were grown on soils from the target sites and root colonisation by ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungi was determined. The ECM root colonisation levels found indicated that soil from Site 2 contained sufficient ECM propagules to serve as a primary source of inoculum for P. pinaster. The low levels of ECM and AM colonisation obtained on the roots of plants grown in soil from Site 1 indicated that the existing mycorrhizal propagules might be insufficient for effective root colonisation of Q. ilex. Different ECM morphotypes were found in plants grown in soil from the two sites. At Site 2 mycorrhizal parameters were found to be spatially structured, with signif icant differences in ECM colonisation and soil P concentrations between regions of either side of an existing watercourse. The spatial distribution of mycorrhizal propagules was related to edaphic parameters (total C and extractable P), and correlations between soil nutrients and mycorrhizal parameters were found.
- Indução de resistência ao nemátode da madeira do pinheiro em plântulas de Pinus spp. através da inoculação com uma estirpe não virulentaPublication . Franco, Albina R.; Rodrigues, Rui; Rodrigues, Ana C.; Vasconcelos, Marta W.