查看更多>>摘要：We introduced here the first loop mediated isothermal amplification (LAMP) assay for the identification of honey fungus, Armillaria ostoyae, a basidiomycote playing an important role in spruce declines in the Palaearctic region. In total, 101 isolates, representing three Armillaria species, were used to develop a new LAMP assay to determine species specific identification. We have here described LAMP primers enhanced with fluorescent dye that are able to amplify A. ostoyae DNA and detect fungi in a fast single step reaction. The detection limit of LAMP was 1 pg of genomic DNA per reaction. We optimized a new LAMP assay for the rapid detection of A. ostoyae using the translation elongation factor 1-?? (tefl) marker and fluorescence labelled oligonucleotide assimilating probe. The LAMP assay does not require any specialized equipment, hence it can be used in the field for the rapid detection of A. ostoyae even using the portable and mobile device. The specificity of the assay was confirmed by the use of A. ostoyae strains and Armillaria cepistipes and Armillaria gallica strains, respectively. In conclusion, the assay could be a rapid, specific, sensitive and low-cost tool for identification of A. ostoyae as well as the first step for expansion of this method in practical applications.
查看更多>>摘要：Seedling quality is an important input affecting the outplanted seedling performance. Morphological attributes and association with symbiotic ectomycorrhizal (ECM) fungi belong to influential traits determining seedling quality. In this study, the effect of pre-sowing applied commercial additives Ectovit (containing hydrogel and ECM fungi), Mycorrhizaroots (ECM fungi and nutrients) and Vetozen (natural mineral fertilizer) on the growth and ectomycorrhiza formation of Norway spruce seedlings grown in nutrient-poor pure peat in an open nursery site was assessed. Two-year-old bareroot seedlings were transplanted into containers. No significant growth differences were detected between treatments for 1 + 0 seedlings but the values of growth parameters (root collar diameter; stem height; shoot, root and total dry weight) of Ectovit-inoculated seedlings were significantly higher than those in the other treatments including the control after the second (2 + 0 seedlings) and the third growing season (2 + 1). Root-to-shoot dry weight ratio and number of root tips were distinctly higher after the third year compared to the previous two years but they were not significantly different between treatments. Mycorrhizaroots and Vetozen did not have any significant effect on seedling development. Although the occurrence of treatment-specific ECM morphotype was detected in Ectovit-inoculated seedlings, the high total ECM colonization of roots in all treatments including the control indicated a crucial impact of naturally occurring fungi on ectomycorrhiza formation.
查看更多>>摘要：Calculating the factor of safety (FS) as slope stability factor is necessary to prevent environmental damage. Therefore, this paper aims to (i) calculate FS using the limit equilibrium approaches and Slide software and (ii) investigate the stability of slopes according to calculated FS (Janbu and Bishop methods) and status of different sites in the study area (Hyrcanian forest of Iran). Six landslides were selected along the forest road by a field survey. Landslide dimensions including length, width, and height were measured using meters. Slope gradients were measured using the Suunto clinometer. The Slide software was used to evaluate the stability analysis of slopes. According to laboratory tests on soil samples the average of the liquid limit was recorded as 58%. The results of the direct shear test showed that the rate of soil cohesion (c) and coefficient of friction angle (1)) decreased with an increase in moisture content. According to the results, the factors of safety for landslide sites (Sites 1-6) were calculated to be 1.3, 0.65, 0.76, 0.55, 1.19 and 1.51, respectively. These calculated FS can accurately determine the slope status in terms of slope stability. According to the software classification, the status of Site 1 is "susceptible to landside". Sites 2, 3 and 4 are "very high risk". Also, the status of Sites 5 and 6 are "high risk" and "stable", respectively. The instability of the slopes in studied sites is related to the drainage system (lack of culverts or ditches) as well as marlstone as bedrock. According to the calculated FS in different sites and comparison of the obtained results with the real conditions of sites, it can be concluded that the slope stability analysis in the Slide software is very accurate and it can be used to determine the factor of safety under different conditions in terms of morphology, hydrology and soil mechanics.
查看更多>>摘要：It is difficult to estimate flood discharges and the flood zones as well as to design hydraulic structures in rivers without using hydrometric stations. Furthermore, using different models to determine the mentioned cases will be accompanied by errors. Therefore, flood marks on the trunks of trees located in the Babolrood riverbed were used to determine the peak discharge, flood flow depth, and flood zone in northern Iran. First, a hydraulic model for the study river was provided using topographic maps with a scale of 1: 1 000, HEC-GeoRAS extension (GIS), and HECRAS model. Then, the flood marks of past floods in the form of silt and clay sediments (deposits on the trees in the riverbed) were evaluated and the maximum flood flow depth was determined. Finally, the peak discharge of the past flood was estimated by the trial-and-error method to achieve the flood flow depth in the different river reaches. Then, the hydraulic model using the flow depth data was calibrated in the reaches, and, in the final step, based on the flood marks of other reaches, the model was validated. According to the results, the maximum instantaneous discharge rate of the study flood was 155 m3??s???1 and the maximum flood flow depth was about 2 m. Furthermore, the results showed that the flood mark data in forest lands can be used as a tool for the calibration and validation of hydraulic models. The present methodology is an efficient method for determining the flood peak discharge, spatial variation of the flood depth, and flood zone in forest watersheds without hydrometric stations.
NSTL
Czech Academy Agricultural Sciences