Ectomycorrhizae (ECM) and soil microfungi were studied in soil cores from seven unequally polluted forest plots spaced at different distances from a fertilizer factory in Lithuania. The abundance of ECM roots and soil microfungi was visibly different in separate investigation plots. Average amount of ECM root tips during the investigation period (2000-2002) in different forests was from 134 to 1017 tips /100 cm3 of soil and the length of ECM roots was from 12.2 to 79.8 cm/100 cm3. The concentration of viable soil fungi revealed during the investigation varied from 1.5 to 566.6 thousands CFU/ g d.w. soil. The forest farthest from the factory exhibited the highest abundance of ECM and diversity of ectomycorrhizal morphotypes, while the abundance of soil microfungi was lowest. The lowest diversity of ECM morphotypes was determined in forests characterized by the highest concentration of heavy metals, nutrients (nitrogen, phosphorus) and the highest microfungal abundance was in forests with the highest concentration of nutrients.
Translocation of selected heavy metals in a mycelium growing in an agar medium supplemented with heavy metals was studied. The study showed that zinc, cadmium and lead were higly accumulated in the mycelium structures and that mycelium actively inhibited metal ion translocation.
The selection of mycorrhizal fungi forming symbiotic association with trees growing in areas contaminated with heavy metals was observed. The aim of this study was to discover how ectomycorrhizal fungi, growing in habitats with high levels of heavy metal contamination, are adapted to this contamination in comparison with fungi that grow in nonpolluted environments. The experiments were performed using a vegetative mycelium isolated from fruiting bodies in clean cultures on agar. Changing concentrations of zinc, cadmium and lead in the growth medium, the growth of mycelium cultures oiXerocomus badius and Amanita muscaria was observed and compared. It was found that strains of Amanita muscaria and Xerocomus badius growing in contaminated areas were adapted to high concentrations of Zn, Cd and Pb. The degree of adaptation was related to the level of contamination of the area where this mycorrhizal fungus survived.
Ectomycorrhizas of Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.) were sampled in a mature forest ecosystem exposed for more than 40 years to moderate levels of gaseous and dust pollutants. Soil of the forest site was characterised by low pH and accumulation of heavy metals (Pb, Mn, Zn, Cu, Cd, Fe). Mycorrhizal vitality and enzyme activity of the root-surface and soil acid phosphatase (AcPase) were studied at 17 measurement points (0–5 cm soil depth) in relation to the content of inorganic phosphate (Pi) and aluminium ions (Al3+) in the soil. Anatomy of Scots pine and beech mycorrhizas taken from different measurement points was observed. The concentration of essential nutrients (C, N, P, Ca, Mg) and the ratios Ca/Al, Mg/Al and N/P were analysed in fine roots. High concentrations of Al3+ in the soil (40–118 meq kg-1) and low levels of Pi (12–44 mg P2O5 kg-1) were accompanied by high activity of the root-surface AcPase of pine and beech mycorrhizas (25–67 and 33–86 μmol pNP g-1 fresh weight h-1, respectively) and soil AcPase (6.8–22.4 μmol pNP g-1 dry weight h-1). The results indicate that fine tree roots are undoubtedly under stress as evidenced by a disturbance in P uptake and accumulation. However, the high vitality of mycorrhizas and the high Ca/Al ratio in fine roots suggest that the defence mechanisms of mycorrhizas and the rhizosphere are still able to ameliorate the influence of anthropogenic pollution.
The paper presents the results of the study on sowing efficiency and the intensity of the post-emergence damping-off of spruce (Picea abies (L.)H.Karst.) seedlings grown on fresh sawdust-peat substratum and utilized for 5, 8 and 11 years ones under a foil tunnels. The frequency of occurrence of mycorrhizae and mycorrhizal spectrum of 4-month-old seedlings grown on those substrata were investigated as well. It was found that a long term utilization of sawdust-peat substrata do not create a threat to spruce seedlings by the damping-off fungi. Tested substrata do not favour a natural formation of mycorrhizae on spruce seedlings. The percentage of mycorrhizae was low and the spectrum of mycorrhizal types was poor.
Scots pine seedlings inoculated with 11 strains Rhizopogon roseolus were planted out on sylviculture area in March 2007. After 2 and 3 vegetation seasons height, stem diameter, number of buds and lateral shoot, length of the lateral shoots last season and seedlings survival were studied. The highest were seedlings inoculated with strain A, C, D, G, J and K (after 2 and 3 years). However the most thickness were seedlings inoculated with strain J (after 2 year) and D, E, J (after 3 year). Survival of seedlings was higher than 85%, without seedlings inoculated strain H.
Pinus sylvestris seedlings grown in containers in a peat-vermiculite substrate were inoculated with vegetative inoculum of 11 strains Rhizopogon roseolus (Corda.) Th. M. Fries. Seeds were germinated in May 2006. Five months after germination the seedlings were evaluated for their growth and development and ectomycorrhizal frequency. There were significant differences between trait seedlings P. sylvestris inoculated 11 strains used in this experiments. The highest mean values of height and steam diameter were obtained with seedlings inoculated with strain G fungus R. roseolus. There were no significant differences between dry weight seedlings inoculated all strains. R. roseolus formed ectomycorrhizae on 100% of the inoculated plants at all variants. The highest colonization of short roots were obtained with seedlings inoculated with strain D this fungus (29%). There were destined strains D, G and I fungus R. roseolus to further studies.