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- 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.
- 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.
- Combined use of Pinus pinaster plus and inoculation with selected ectomycorrhizal fungi as an ecotechnology to improve plant performancePublication . Oliveira, Rui S.; Franco, Albina R.; Castro, Paula M.L.Pinus pinaster is an important forest species for environmental and economic reasons. Due to its importance, tree improvement plans aimed at the selection and use of phenotypically superior trees, designated by plus trees, have been established. It is known that ectomycorrhizal (ECM) fungi can improve tree survival and growth. Seeds obtained from P. pinaster plus trees have been used in forest nurseries. However, the effect of inoculation with ECM fungi on the performance of these plants has not been studied. We compared the performance of P. pinaster plants obtained from seeds of plus and non-plus trees to inoculation with different selected ECM fungi under conventional forest nursery conditions. In plants obtained from seeds of non-plus trees only those inoculated with Suillus bovinus + Laccaria laccata + Lactarius deterrimus had a significantly greater biomass and needles nitrogen concentration, while in plants obtained from seeds of plus trees this effect was seen not only in those receiving that same ECM inoculation, but also in those inoculated with Rhizopogon roseolus or Pisolithus tinctorius + Scleroderma citrinum. The best performance was that of plants obtained from seeds of plus trees and inoculated with R. roseolus or S. bovinus + L. laccata + L. deterrimus, with an increase in biomass of 2.2 and 2.0 times, respectively. This significant improvement was achieved without extra input of agrochemicals. The combined use of seeds obtained from plus trees and inoculation with selected ECM fungi can be an advantageous ecotechnological approach to improve nursery production of P. pinaster
- Management of nursery practices for efficient ectomycorrhizal fungi application in the production of Quercus ilexPublication . Oliveira, Rui S.; Franco, Albina R.; Vosátka, Miroslav; Castro, Paula M. L.
- Tree breeding and mycorrhizal symbiosis as important tools in forestation processesPublication . Sousa, Nadine R.; Ramos, Miguel A.; Franco, Albina R.; Oliveira, Rui S.; Castro, Paula M. L.Higher growth rate and morphological traits have been the major criteria for selecting trees classified as improved in breeding programs. The symbiotic associations between P. pinaster and ectomycorrhizal fungi can be an effective approach to enhance plant development. The aim of this work was to assess whether the establishment of mycorrhizal symbiosis at nursery stage was affected by tree breeding. P. pinaster improved and non-improved seedlings were inoculated with compatible ectomycorrhizal fungi: Suillus bovinus, Pisolithus tinctorius or Rhizopogon roseolus, and grown in individual cells containing forest soil, in a commercial forest nursery. Growth and nutritional traits, colonisation parameters and the fungal community established were assessed. R. roseolus and P. tinctorius were the most efficient isolates in promoting plant development. Inoculated improved saplings had an overall superior development than their non-improved counterparts, with up to a 4.9-fold in root dry weight and a 13.6-fold increase in the total number of ectomycorrhizal root tips. Differences in fungal community were revealed through the denaturing gradient gel electrophoresis profile of each treatment. The results from our study suggest that improved seedlings benefit more from the mycorrhizal association and therefore this could be a valuable biotechnological tool for the nursery production of improved P. pinaster.
- Degradation of 3-fluorophenol and Sodium Trifluoroacetate by Ectomycorrhizal fungiPublication . Franco, Albina R.; Ramos, Miguel; Sousa, Nadine R.; Silva, Débora S.; Oliveira, Rui S.; Castro, Paula M. L.
- Effect of diflubenzuron on the development of Pinus pinaster seedlings inoculated with the ectomycorrhizal fungus Pisolithus tinctoriusPublication . Ramos, Miguel A.; Sousa, Nadine R.; Franco, Albina R.; Costa, Vítor; Oliveira, Rui S.; Castro, Paula M. L.Diflubenzuron (DFB) is an insecticide commonly used to control forest pests. The objectives of this study were to assess the effect of diflubenzuron on the development of Pinus pinaster seedlings and Pisolithus tinctorius under laboratory conditions and to study the possible protective role of this ectomycorrhizal fungus against the effects of diflubenzuron. In vitro experiments revealed that diflubenzuron inhibited fungal growth at all tested concentrations (0.01, 0.1, 1, 10 and 100 mg L−1). Root growth was inhibited at the two highest diflubenzuron concentrations. The activity of the antioxidant defence system of non-inoculated P. pinaster increased at 1 and 10 mg DFB kg−1 substrate, and inoculation increased the threshold to the highest concentration. The protective role of the ectomycorrhizal fungus was seen in the increase of CAT activity. This study revealed that despite causing no mortality, diflubenzuron has the ability to cause sub-lethal damage to P. pinaster. The disproportionate use of this insecticide may lead to higher amounts of its residues in soil and the biosphere, endangering trees, fungi and their symbiosis.
- Management of nursery practices for efficient ectomycorrhizal fungi application in the production of Quercus ilexPublication . Oliveira, Rui S.; Franco, Albina R.; Vosátka, Miroslav; Castro, Paula M. L.The application of ectomycorrhizal (ECM) fungi on forest nursery production is regarded as part of good management practice. However, before employing large scale inoculations in a nursery the interaction between ECM symbionts, growth substrate and fertilisation input should be studied to select the most suitable nursery practices for promoting plant growth and ECM colonisation. In this study, seedlings of Quercus ilex were inoculated with Paxillus involutus, Hebeloma mesophaeum or Cenococcum geophilum and grown in three different substrates commonly used in forest nurseries: peat-based compost, forest soil or composted pine bark. The effect of various fertilisation regimes was also studied. The choice of substrate had a significant effect on plant growth and ECM colonisation. The most appropriate combination of substrate and ECM fungus for Q. ilex growth and nutrition was peat and H. mesophaeum. Plants grown on a peat-based compost and inoculated with H. mesophaeum had a significantly greater biomass and leaf phosphorus concentration without fertilisation. Composted pine bark was found not to be suitable for growth or for mycorrhization. If the appropriate growth substrate is selected, it is possible to replace the use of chemical fertilisers by inoculation with selected ECM fungi. This results in a significant increase in plant development, and thus ECM fungi can be recommended as a more environmental friendly biotechnological approach to plant management in the nursery.