Surface mining causes major destruction of natural landscapes and ecosystems. The most fertile, surface soil layer is lost permanently, together with vegetation, wildlife, and micro flora. Post-mining areas are characterized with diverse edaphic, topographic, hydrographic conditions, which complicate land restoration. Successful establishment of forest ecosystems on such land depends mostly on selection of tree species. The chosen plants must be capable of tolerating a wide range of acidity, fertility, moisture, and have potential to ameliorate such substrates for more demanding species. But, reforestation of heavily damaged ecosystems, such as post-mining areas, demands a new approach in seedlings production. This new approach takes into account specific requirements of habitat and integrates them into "targeted production of planting material". A good strategy for successful reforestation of post-mining areas is the input of organic matter (compost, mulch). Also, current knowledge and experiences emphasize the potential of beneficial microorganisms such as, mycorrhizal fungi (MF) and plant growth promoting rhizobacteria (PGPR). The majority of studies that deal with beneficial interactions between trees and microorganisms are focused on the mycorrhiza, while plant growth promoting rhizobacteria are less present in silviculture. In this study, the focus is on the reforestation challenges of two mining basins, Majdanpek and Kolubara and suggests beneficial microorganisms as potential solution. The study presents results of several years' researches on plant response to the presence of mycorrhizal fungi and PGPR. The substrates used for plant growth were Majdanpek and Kolubara mine deposals. Mycorrhizal seedlings were grown in Majdanpek mine deposal, and at the end of the experiment they had 30% higher biomass in comparison to control (seedlings without mycorrhiza). Seedlings linked with fungi had a higher survival rate. Deposals from Kolubara Mining Basin were used as a substrate for seedlings inoculated with PGPR. In the first experiment, Scots pine and Norway spruce were inoculated with Azotobacter chroococcum, Bacillus megaterium, B. circulans, B. licheniformis, B. pumilus, B. amyloliquefaciens. Inoculation resulted with higher biomass production (Scots pine 43%, Norway spruce 34%). Similar results were obtained in the second experiment where Scots pine and black locust were inoculated with Bacillus licheniformis, Aeromonas hydrophila, Pseudomonas putida and Burkholderia cepacia. Both species had higher biomass (around 20%) in comparison to un-inoculated control. The results confirmed the fact that early establishment and successful growth of vegetation on devastated areas depends on the presence and activity of soil microbes. Microorganisms as a "nature's solution" pose the potential to alleviate reforestation challenges of anthropogenic devastated landscapes. Their presence and activity is crucial for ecosystem stability. In areas with compromised balance, their introduction is justified action fo...

(1)Overburden waste dumps represent a huge threat to environmental quality. The reduction of their negative impact can be achieved by vegetation cover establishment. Usually, this action is complicated due to site-specific characteristics, such as nutrient deficiency, elevated metal concentration, low pH value, lack of moisture and lack of organic matter. Establishment of vegetation can be facilitated by inoculation with plant growth promoting bacteria (PGPB) which improve the physicochemical and biological properties of degraded substrates and make them more hospitable for plants. In this study we selected several strains based on the ability to produce ammonia, indole-3-acetic acid, siderophores and lytic enzymes, and to solubilize inorganic phosphates. This selection resulted in microbial consortia consisting of Serratia liquefaciens Z-I ARV, Ensifer adhaerens 10_ ARV, Bacillus amyloliquefaciens D5 ARV and Pseudomonas putida P1 ARV. The effects of PGPB consortia on one-year-old London plane (Platanus × acerifolia [Aiton] Willd.) seedlings replanted into overburden waste from Kolubara Mine Basin were examined. After seven months, inoculated seedlings were 32% higher with 45% wider root collar diameter and over 80% higher total dry biomass compared to uninoculated seedlings grown in Kolubara's overburden. Inoculation resulted in higher amounts of total soluble proteins, higher chlorophyll and epidermal flavonoids content and higher total antioxidative capacity in the leaves. This study represents a successful search for effective PGPB strains and shows that microbial consortia have an important role in enhancing the growth of seedlings in nutrient deficient and degraded substrates such as overburden waste from open-pit coal mines. Positive response of London plane seedlings suggest that inoculation may help widening the opus of species for reforestation of post mining areas and speed up natural succession processes and recovery of degraded landscapes.

Bioremediation is promising technology for dealing with oil hydrocarbons contamination. In this research growth kinetics and oil biodegradation efficiency of Pseudomonas luteola PRO23, isolated from crude oil-contaminated soil samples, were investigated under different concentrations (5, 10 and 20 g/L) of light and heavy crude oil. More efficient biodegradation and more rapid adaptation and cell growth were obtained in conditions with light oil. The 5 to 10 g/L upgrade of light oil concentration stimulated the microbial growth and the biodegradation efficiency. Further upgrade of light oil concentration and the upgrade of heavy oil concentration both inhibited the microbial growth, as well as biodegradation process. Aminoglycosides stimulated biosurfactant production in P. luteola in the range of sub-inhibitory concentrations (0.3125, 0.625 ?g/mL). Aminoglycosides also induced biofilm formation. The production of biosurfactants was the most intense during lag phase and continues until stationary phase. Aminoglycosides also induced changes in P. luteola growth kinetics. In the presence of aminoglycosides this strain degraded 82% of diesel for 96 h. These results indicated that Pseudomonas luteola PRO23 potentially can be used in bioremediation of crude oil-contaminated environments and that aminoglycosides could stimulate this process. [Projekat Ministarstva nauke Republike Srbije, br. TR31080]

The Botryosphaeriales represents a diverse order of fungal pathogens of various woody plant species. In Serbia, these fungi are important pathogens of forest, ornamental and fruit trees causing die-back, cankers, leaf blights, fruit, and root rot. The aim of this study was to evaluate the antifungal activity of Pinus sylvestris bark extracts and Trichoderma spp. against Botryosphaeria dothidea, Dothiorella sarmentorum and Neofusicoccum parvum (Ascomycota: Botryosphaeriales) isolated from Picea abies, Thuja occidentalis and Prunus laurocerasus trees planted in urban areas in Serbia. Bark extracts were prepared in water solution at two temperatures (80 and 120 ºC). The extracts were tested using two concentrations (20 and 30%). Moreover, two Trichoderma isolates obtained from P. sylvestris bark were tested against Botryosphaeriales and their antagonistic potential was estimated in vitro using a confrontation test. Mycelial growth of B. dothidea and D. sarmentorum was significantly inhibited in the presence of bark extracts, while N. parvum showed no growth inhibition. Botryosphaeria dothidea growth was inhibited by 35 to 39% in the case of 20% extracts and by 39 to 44% in the case of 30% extracts. The growth inhibition of D. sarmentorum was between 48 to 56% in the case of 20% extracts and 53 to 60% in the case of 30% extracts. The two Trichoderma isolates showed antifungal activity against the selected pathogens. An isolate BKG 4 showed the highest inhibition level and it inhibited the growth of B. dothidea, D. sarmentorum and N. parvum by 85, 75 and 62%, respectively. Preliminary results suggest that both P. sylvestris bark extracts and Trichoderma spp. could be used as biocontrol agents against B. dothidea, D. sarmentorum and N. parvum, and this deserves a further study.

Modern, efficient, and cost-effective approach to remediation of heavy metal-contaminated soil is based on the application of microorganisms. In this paper, four isolates from agricultural and urban contaminated soil showed abundant growth in the presence of copper(II) sulfate pentahydrate (CuSO·5HO) up to 2 mM. Selected yeasts were identified by molecular methods as Candida tropicalis (three isolates) and Schwanniomyces occidentalis (one isolate). C. tropicalis (4TD1101S) showed the highest percentage of bioaccumulation capabilities (94.37%), determined by the inductively coupled plasma optical emission spectrometry (ICP-OES). The Raman spectra of C. tropicalis (4TD1101S) analyzed in a medium with the addition of 2 mM CuSO·5HO showed certain increase in metallothionein production, which represents a specific response of the yeast species to the stress conditions. These results indicate that soil yeasts represent a potential for practical application in the bioremediation of contaminated environments.