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It is recognized that inoculation with ectomycorrhizal (ECM) fungi can have a positive effect on the establishment of nursery grown seedlings and influence their survival during the first years. However, an increased effort is needed to understand their role and behavior in abandoned burned areas. We investigated tree performance of pre-inoculated Quercus rubra seedlings on a site with fire history and monitored fungal persistence and succession dynamics of the ectomycorrhizal community established. Nursery grown Q. rubra seedlings inoculated with a mixture of 6 ECM fungi ( Cenococcum geophilum , Hebeloma crustuliniforme , H. mesophaeum , H. velutipes , Paxillus involutus and Scleroderma citrinum ) were transplanted to Serra da Cabreira, Northern Portugal. Non-inoculated control oak seedlings were also transplanted. Two years after planting, biometric and mycorrhizal parameters were determined. The presence of the inoculated ECM fungi and the dominant ECM fungal community established was assessed by DGGE-cloning. Results showed that the bioinoculants improved the growth performance of outplanted oak seedlings, promoting a c.a. 1.6-fold increase in height and a 2.9-fold increase in the number of ECM root tips. After two years, H. mesophaeum , H. velutipes , P. involutus and S. citrinum persisted in the root system of inoculated plants. Ordination analysis demonstrated that ECM fungal communities of inoculated and non-inoculated samples were significantly different. The present work reinforces the benefits of using nursery inoculated plants in forest reclamation processes.

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.

Soil contamination with Cd is of primary concern and beneficial soil restoration strategies urge. The aim of this work is to evaluate the response of two different genotypes of Pinus pinaster (wild and selected) to Cd contamination and to assess how inoculation with ectomycorrhizal fungi, Suillus bovinus and Rhizopogon roseolus, influenced each genotype. Seedlings were exposed to soil contaminated at 15 and 30 mg Cd kg−1. Plant growth, mycorrhizal traits and Cd accumulation in different tissues of the plant were determined at harvest. The fungal community was assessed by denaturing gradient gel electrophoresis. At 15 mg Cd kg−1 S. bovinus increased aboveground development in both genotypes. At 30 mg Cd kg−1 non-inoculated wild genotype accumulated more Cd in the shoots (1.7-fold) than the selected genotype; inoculation with R. roseolus decreased Cd concentration in the roots of the selected genotype whereas the opposite occurred in the wild genotype. Cd concentration in the root system was the parameter most influenced by the interaction between the three studied variables. The fungal community established was affected by the Cd concentration in the soil. Results show that different genotypes of P. pinaster react differently to Cd exposure depending on the mycorrhizal association. The importance of considering the combination between plant genotype and its symbiotic partners when aiming at the forestation of degraded land is highlighted.