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11.
Fungal decomposition of and phosphorus transformation from spruce litter needles (Picea abies) were simulated in systems containing litter needles inoculated with individual saprotrophic fungal strains and their mixtures. Fungal strains of Setulipes androsaceus (L.) Antonín, Chalara longipes (Preus) Cooke, Ceuthospora pinastri (Fr.) Höhn., Mollisia minutella (Sacc.) Rehm, Scleroconidioma sphagnicola Tsuneda, Currah & Thormann and an unknown strain NK11 were used as representatives of autochthonous mycoflora. Systems were incubated for 5.5 months in laboratory conditions. Fungal colonization in systems and competition among strains were assessed using the reisolation of fungi from individual needles. After incubation, needles were extracted with NaOH and extracts were analysed using 31P nuclear magnetic resonance spectroscopy (NMR). Needle decomposition was determined based on the decrease in C:N ratio. Systems inoculated with the basidiomycete S. androsaceus revealed substantial decrease in C:N ratio (from 25.8 to 11.3) while the effect of ascomycetes on the C:N ratio was negligible. We suppose that tested strains of saprotrophic ascomycetes did not participate substantially in litter decomposition, but were directly involved in phosphorus transformation and together with S. androsaceus could transform orthophosphate monoesters and diesters from spruce litter needles into diphosphates, polyphosphates and phosphonates. These transformations seem to be typical for saprotrophic fungi involved in litter needle decomposition, although the proportion of individual phosphorus forms differed among studied fungal strains. Phosphonate presence in needles after fungal inoculation is of special interest because no previous investigation recorded phosphonate synthesis and accumulation by fungi. Our results confirmed that the 31P NMR spectroscopy is an excellent instrumental method for studying transformations of soil organic phosphorus during plant litter decomposition. We suggest that polyphosphate production by S. androsaceus may contribute to the phosphorus cycle in forest ecosystems because this fungus is a frequent litter colonizer that substantially participates in decomposition. 相似文献
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Novotny V Drozd P Miller SE Kulfan M Janda M Basset Y Weiblen GD 《Science (New York, N.Y.)》2006,313(5790):1115-1118
Despite recent progress in understanding mechanisms of tree species coexistence in tropical forests, a simple explanation for the even more extensive diversity of insects feeding on these plants has been missing. We compared folivorous insects from temperate and tropical trees to test the hypothesis that herbivore species coexistence in more diverse communities could reflect narrow host specificity relative to less diverse communities. Temperate and tropical tree species of comparable phylogenetic distribution supported similar numbers of folivorous insect species, 29.0 +/- 2.2 and 23.5 +/- 1.8 per 100 square meters of foliage, respectively. Host specificity did not differ significantly between community samples, indicating that food resources are not more finely partitioned among folivorous insects in tropical than in temperate forests. These findings suggest that the latitudinal gradient in insect species richness could be a direct function of plant diversity, which increased sevenfold from our temperate to tropical study sites. 相似文献
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Josef Velisek Alzbeta StaraJana Machova Petr DvorakEliska Zuskova Miroslav ProkesZdenka Svobodova 《Pesticide biochemistry and physiology》2012,102(1):102-108
The aim of this study was to assess the toxicity of terbutryn to early developmental stages of common carp (Cyprinus carpio). Based on accumulated mortality in the experimental groups, lethal concentrations of terbutryn were estimated at 36 day LC50 = 3.06 mg l−1 terbutryn. Based on inhibition of growth in the experimental groups, lowest observed-effect concentration (LOEC) = 0.005 mg l−1 terbutryn; and no observed-effect concentration (NOEC) = 0.0007 mg l−1 terbutryn. Fulton’s condition factors were significantly lower in fish exposed to 2 mg l−1 compared with controls. By day 30, fish exposed to 0.00002 mg l−1 - real environmental concentration in Czech rivers - 0.02, 0.2, and 2 mg l−1 terbutryn showed significantly lower mass and total length compared with controls. No significant negative effects on hatching or embryo viability were demonstrated at the concentrations tested, but significant differences in early ontogeny among groups were noted. Fish from the two highest tested concentrations (0.2 and 2 mg l−1) showed a dose-related delay in development compared with the controls. At concentrations of 0.02, 0.2, and 2 mg l−1 damage to caudal kidney tubules when compared to control fish was found. 相似文献
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Churchward CP Hlúšek M Nicholas RA Ayling RD McAuliffe L 《Veterinary microbiology》2012,159(1-2):257-259
Mycoplasma mycoides subspecies mycoides small colony is the aetiological agent of contagious bovine pleuropneumonia, a cattle disease endemic to areas of sub-Saharan Africa. Twenty isolates from various geographical locations and the type strain were analysed by multi-locus sequence analysis (MLSA). The data generated was then used to develop three PCR primer sets to differentiate these isolates. The PCRs differentiated the isolates into four groups; the type strain (T); isolates of European origin (Eu); isolates from Tanzania (Af1) with a final group consisting of isolates from Namibia and Botswana (Af2). These PCRs offers a rapid and efficient post-identification typing method without the need to sequence and analyse multiple genes. 相似文献
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Jelena Tomić Milica PojićAleksandra Torbica Slađana RakitaDragan Živančev Elizabet Janić HajnalTamara Dapčević Hadnađev Miroslav Hadnađev 《Journal of Cereal Science》2013
The main aim of this study was to determine the changes in free sulphydryl content during postharvest wheat and flour maturation. The content of free sulphydryl groups was determined from wet gluten over 50 days of wheat postharvest maturation and over 14 days of flour maturation by varying incubation temperatures (30 and 37 °C) and incubation times (0, 45, 90 and 135 min). The amount of free sulphydryl groups increased during postharvest wheat and flour maturation as well as with the increase in temperature and gluten incubation time. The additional aim of this study was to find the interrelation between the content of free sulphydryl groups and selected parameters of technological quality by means of Principal Component Analysis. During wheat/flour maturation, the strengthening of protein structure was observed manifested by the increase in gluten index and Mixolab protein network weakening (C2), and changes in dough resistance as well. The incubation temperature of 37 °C affected the weakening of protein structure manifested by the decrease in gluten index and resistance, and increase in extensibility. Strong differentiation of examined varieties in terms of selected quality indicators was observed upon pre-defined maturation period, probably due to the expression of their intrinsic properties. 相似文献
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Branimir Jovančićević Mališa Antić Ivona Pavlović Miroslav Vrvić Vladimir Beškoski Alexander Kronimus Jan Schwarzbauer 《Water, air, and soil pollution》2008,190(1-4):299-307
This paper presents transformations of saturated hydrocarbons of petroleum type pollutants during ex situ bioremediation of soil on the pilot heap (halde), during a period of 6 months, within the grounds of Petroleum Refinery Pan?evo (Serbia). Samples for analysis were taken in time intervals of 2 weeks (P1–P12 samples). Organic substance was extracted by Soxhlet’s method and quantified. Isoprenoid aliphatics, in particular pristane and phytane, and polycyclic aliphatics of sterane and triterpane types in saturated hydrocarbon fractions were analysed by GC-MS (SIM method). Significant amounts of n-alkanes have not been detected. The MS-chromatogram revealed only marginal amounts of pristane and phytane in sample P1. Pristane and phytane occurred in sample P8, and in even higher quantities in the final sample P12. The proceeding bioremediation process was accompanied by the decrease of the relative amounts of pentacyclic terpanes of hopane type, compared to tri- and tetracyclic terpanes. In the initial sample P1 the distribution of steranes and hopanes follows a pattern, which is characteristic for crude oils. However, their identification by SIM method was not possible in samples P8 and P12 because of the reduced concentration. The observed changes in the alkane fractions’ compositions may be considered as atypical, referring to the fact that during oil biodegradation under natural conditions, decomposition of isoprenoids occurs much easier and faster than decomposition of polycyclic alkanes of tri-, tetra- and pentacyclic terpane, sterane and diasterane types, after the decomposition of n-alkanes has been almost completed. 相似文献
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Bojan Mitrović Miroslav Zorić Sreten Terzić Dalibor Živanov Petar Čanak Branko Milošević Đura Karagić 《Plant Breeding》2023,142(4):407-417
Use of varieties bred under organic conditions is essential in order to minimize the yield gap between organic and conventional agriculture. The aim of this study was to analyse research publications related to the topic ‘organic plant breeding’ from the Web of Science database using bibliometric science mapping and visualization tools. The number of analysed documents in the bibliographic dataset was 204 from the 53 sources. The overall trend in the organic plant breeding literature showed that the number of publications increased during the observed time-span. We found that in total, 65 countries and 337 institutions are active in the field of organic plant breeding with a high degree of international collaboration. The top five countries according to the number of publications were the United States, Italy, Germany, France, and Canada, while the most active institutions were Wageningen University, Iowa State University, University of Alberta, University of Copenhagen, and University of Hohenheim. All keywords from the organic plant breeding research in the agronomy category were separated into seven clusters for different research topics. Although there is evident progress viewed through the increased trend in the number of publications, organic plant breeding needs further expansion and development. This is especially through the implementation of novel plant breeding techniques and methods aiming to improve traits that are highly specific to organic conditions. 相似文献
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