Browsing by Issue Date, starting with "2012-06-24"
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- Plant growth promoting potential of rhizobacteria isolated from a contaminated areaPublication . Pereira, Sofia I. A.; Barbosa, Liliana; 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.
- Two genotypes of mycorrhizal Pinus pinaster respond differently to cadmium contaminationPublication . Sousa, Nadine R.; Ramos, Miguel A.; Marques, Ana P. G. C.; Castro, Paula M. L.Fertilization is one of the main anthropogenic sources of Cd accumulation in agricultural soils and when toxic levels have been reached, food crop production is no longer viable. Adequate strategies for the forestation of agricultural metal contaminated sites are of vital importance. The aim of this work was to evaluate the response of two different genotypes of P. pinaster (A and B) to Cd contamination and to assess how inoculation with ectomycorrhizal fungi influenced each genotype. Seedlings were exposed to soil contaminated at different levels of Cd. At 30 mg Cd kg-1 non-inoculated genotype A accumulated more Cd in the shoots. At the lowest Cd concentration S. bovinus decreased Cd shoot concentration and increased aboveground development in both genotypes. At the highest Cd dosage inoculation with R. roseolus decreased Cd concentration in the roots of genotype B whereas the opposite occurred in genotype A. The results from this study suggest that the selection of an adequate combination between genotype and associated mycobionts may be an important biotechnological tool to enhance the efficiency of forestation and phytoremediation processes of degraded land using P. pinaster.