Effect of arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) on microorganism of phenanthrene and pyrene contaminated soils.

A pot experiment was performed to investigate the effect of phytoremediation (CK, using tall fescue), fungi remediation (GV, using Glomus versiforme), bacterial remediation (PS, using Pseudomonas fluorescens Ps2-6), and microbial-phytoremediation (GVPS, using three species) on removing polycyclic aromatic hydrocarbons (PAHs) and the microbial diversity in soils. Inoculation with G. versiforme and P. fluorescens could increase the biomass of tall fescue and the accumulation of phenanthrene (PHE) and pyrene (PYR) in plants. Among them, the highest PHE and PYR removal efficiencies and highest biomass of tall fescue were observed in the GVPS treatment and the microbial diversity in contaminated soil was changed, the result revealed that Proteobacteria and Ascomycota were the dominant bacterial phylum and fungal phylum in all treatments, while more Proteobacteria were detected in GVPS treatment. At the genus level, the abundance of Sphingomonas (3.17%), Pseudomonas (2.05%), and Fusarium (8.65%) treated with GVPS increased compared with other treatments. These pieces of evidence contribute to a better understanding of the mechanisms involved in the combined microbial-phytoremediation strategies for PAHs-contaminated soils, especially the effects of microbial-phytoremediation on rhizosphere microbial diversity.

Inoculation with G. versiforme and P. fluorescens could increase PHE and PYR removal efficiencies, the biomass of tall fescue, microbial diversity, and the abundance of Proteobacteria, Sphingomonas, Pseudomonas, and Fusarium in (PHE + PYR)-contaminated soils.

Trait value and phenotypic integration contribute to the response of exotic Rhus typhina to heterogeneous nitrogen deposition: A comparison with native Rhus chinensis.

The temporal heterogeneity of nitrogen availability in soils is increasing due to agricultural deposition. We here compared the effects of gradually increasing nitrogen deposition rate and its increasing temporal heterogeneity patterns on the functional traits of seedlings of exotic species Rhus typhina and the native species Rhus chinensis. Nitrogen deposition rates of 0, 8, 20 g N m-2 year-1 and constant, single-peak, and double-peak nitrogen were added to simulate deposition rate and temporal heterogeneity. After 60 days of treatment, R. typhina seedlings had several advantageous growth trait values, such as higher total biomass production, but lower phenotypic plasticity than R. chinensis seedlings. R. typhina seedlings also had higher phenotypic integration, measured as the correlation among functional traits. The increased nitrogen deposition rate affected several traits of the two species differently. Thus, while R. chinensis seedlings allocated more biomass to leaves and less to roots with increasing N deposition, R. typhina seedlings had stable biomass allocation among all N treatments. Chlorophyll content, leaf phosphorus concentration, and water use efficiency increased, but the maximum net photosynthetic rate decreased, with N availability in R. chinensis, but not in R. typhina. Temporal heterogeneity had no significant effect on the total biomass of R. typhina and R. chinensis seedlings. Overall, the performance of R. typhina is better than that of R. chinensis seedlings under different nitrogen deposition treatments, which is due to the significantly advantageous trait values and greater phenotypic integration of R. typhina seedlings, whereas R. chinensis seedlings have higher phenotypic plasticity.

[Diversity and Community Structure of Airborne Fungi in Different Working Areas of Composting Plants].

Composting plants are an important source of airborne fungi. At present, no research has been reported on differences in the types and abundance of escaped fungi in different working areas, which makes it very difficult to comprehensively assess the ecological health risks of the air in composting plants. In light of this situation, this study collected air samples from the composting, packaging, office, and downwind areas of the composting plants and used high-throughput sequencing technology to analyze and compare the biological diversity and community structure of airborne fungi in the four areas. The source of airborne fungi in offices and downwind areas was further traced. The results showed that the highest abundance and diversity of airborne fungi were found in the packing and composting areas of the composting plants. Ascomycota and Basidiomycota were two fungal phyla with the highest relative abundance in the four regions. Overall, the distribution of dominant fungal genera differed; Trichocomaceae and Davidiella were the dominant genera in three areas of the composting plants. Among the 136 detected fungal genera, the number of endemic airborne fungal genera in the composting and packaging area was the largest, and 52.94% of the fungal genera was shared by the four areas. At the level of fungal genera, the community structures in the air in three areas of the composting plants were similar. The statistical difference analysis results of the key genera in different areas of the composting plants showed that the number of different fungal genera between the downwind, packaging, and composting areas was the largest, and no statistically different fungal genera were detected in the air between the packaging and composting areas. The Source Tracker analysis results showed that the contribution percentage of the packaging and composting areas to the airborne fungi in the office and downwind areas was between 9.52%-15.85%. The results of this study will provide basic data for evaluating the relationship between airborne fungal exposure and human health in different areas of the composting plant, as well as its ecological impact on the surrounding air environment.