Characterization of ectomycorrhizal fungal communities associated with tree species on an iron tailings deposit undergoing restoration.

Vegetation restoration is an effective method to improve the ecological environment of mine tailings, which has a profound impact on the potential ecological functions of soil fungal communities; yet, little is known about its beneficial effect on soil ectomycorrhizal fungal community. In this study, the responses of soil characteristics and soil ectomycorrhizal fungal community diversity and structure to different revegetation, as well as the contribution of soil factors to soil ectomycorrhizal community were investigated in Liaoning Province, China. As we anticipated, the presence of vegetation significantly improved most soil properties we studied. What's more, compared to Korean pine (Pinus koraiensis Sieb. et Zucc.), Chinese poplar (Populus simonii Carr), and black locust (Robinia pseudoacacia L) could better improve soil total carbon, total nitrogen, total phosphorus, and available phosphorus. In addition, soil ectomycorrhizal fungal community diversity in black locust was greater than Korean pine and Populus simonii. Nonmetric multidimensional scaling analyses indicated that soil ectomycorrhizal community significantly differed depending on different revegetation types. Thus, these results indicated that black locust could be a suitable species for the revegetation of iron mine tailings. The study provided theoretical basis for ecological restoration of iron mine tailings using local plant species.

Variations of soil microbial communities accompanied by different vegetation restoration in an open-cut iron mining area.

Overexploitation of iron mining in China has caused serious environmental pollution. Therefore, establishing a stable ecological restoration with vegetation in mining areas has gradually aroused people's awareness and obtained extensive concerns. This study aimed to evaluate vegetation restoration with Robinia pseudoacacia (RP), Acer mono (AM) and Pinus koraiensis (PK) in iron mining compared with unrestored area, to investigate the soil environment factors and microbial communities, and to better understand the correlations between soil environment factors and soil microbial communities. Vegetation restoration could reduce soil pH and alleviate soil alkaline, and remarkably increase soil nutrients, especially in RP site. Analysis of 16S rRNA and ITS rRNA gene sequences provided a total of 645,004 and 906, 276 valid sequences clustered into 7091 OTUs and 1689 OTUs at a 0.03 genetic distance for bacteria and fungi, respectively. The predominant bacterial and fungal phyla were Actinobacteria and Ascomycota in studied sites, respectively. Additionally, revegetation significantly increased the relative abundances of Proteobacteria, Gemmatimonadetes, Bacteroidetes and Patescibacteria, and decreased the relative abundance of Actinobacteria. Robinia pseudoacacia harbored the highest soil fungal community diversity, and bacterial Simpson index and Shannon index. Vegetation restoration with RP could clearly shifted soil communities compared to AM and PK. Along with the restoration of vegetation, the remarkable abiotic changes were the accumulation of total C, total N, total P, available P, available N and available K and the decreasing of soil pH, which were the most important factors affecting soil microbial communities. Our results addressed that Robinia pseudoacacia was the best preferable species than AM and PK in improving soil nutrients, soil community diversity and structure in Fe mining, providing a helpful guideline for selection of tree species.

Molecular characterization and expression of Piwil1 and Piwil2 during gonadal development and treatment with HCG and LHRH-A2 in Odontobutis potamophila.

Piwi proteins play an important regulatory role in germ cell division during gametogenesis and gonad development. In order to understand the function of Piwi genes in the reproductive process of the dark sleeper, we identified and characterized Piwil1 and Piwil2 from gonad tissue. The tissue distribution demonstrated that Piwils were highly expressed in the gonad of the dark sleeper. During gonad development, higher expression was observed in stage I of both the testes and ovaries than in subsequent stages at mRNA and protein levels. The results of immunohistochemistry demonstrated that Piwils were predominantly distributed in the spermatogonia, spermatocytes, and early oocytes. When treated with the HPG axis hormone (HCG and LHRH-A2), the expression of Piwils was significantly decreased in the testes and ovaries at mRNA and protein levels. All of these results indicated that Piwils play a vital role in gonad development and gametogenesis. Our findings provide valuable evidence to further clarify the underlying modulation mechanism of Piwils in teleosts.

[Effects of Festuca arundinacea on the microbial community in crude oil-contaminated saline-alkaline soil].

By using the routine soil physical and chemical analysis methods and the Biolog technique, this paper studied the effects of Festuca arundinacea growth on the pH value, total salt content, and microbial community in the rhizosphere of crude dil-contaminated saline-alkaline soil in Songnen Plain of Northeast China. Crude oil contamination resulted in the increases of average well color development (AWCD), Shannon index (H), and carbon source utilization richness index (S), and altered the utilization patterns of carbon sources by the microbes. F. arundinacea had greater potential to remediate crude oil-contaminated soil. This plant could decrease the soil pH and soil total petroleum hydrocarbon (TPH) content, and increase the soil water content. The AWCD and S in F. arundinacea rhizosphere soil were obviously higher than those in the soil of naked land, providing a suitable environment for the growth and development of rhizosphere soil microbes.

[Effects of combined fertilization of N, P, and K on nicotine content of filling type flue-cured tobacco].

An orthogonal regression field experiment was conducted to study the effects of combined fertilization of N, P, and K on the nicotine content in the upper leaves of filling type flue-cured tobacco (Nicotiana tobacum) variety "Longjiang 911" from Northeast China. The regression effect models of N, P, and K fertilization rates and upper leaf nicotine content were established, and the effects of the fertilization rates and their interactions were analyzed. Based on these, an optimized NPK fertilization scheme was drawn up to reduce the nicotine content in the upper leaves of "Longjiang 911". The model analyses showed that the nicotine content in the upper leaves of "Longjiang 911" decreased after an initial increase with the increasing fertilization rate of N, increased with the increasing fertilization rate of P, and had a sharp decrease with the increasing fertilization rate of K. The two-factor effects of NKP on the nicotine content were in the order of NK >PK>NP. Within a certain range of fertilization rates, NP and PK had negative correlations with the nicotine content, suggesting the antagonistic effects between N and P and between P and K, while NK was on the contrary, suggesting the synergistic effects between N and K. A comprehensive analysis on the regression effect models of N, P, and K fertilization rates and upper leaf nicotine content showed that the basal fertilization rates of N, P, and K for the tobacco production on warp soil were recommended as 33.5-47.8 kg x hm(-2), 40.2-63.6 kg x hm(-2), and 78.0-119.6 kg x hm(-2), respectively.