Lignite pre-treatment and its effect on bio-stimulative properties of respective lignite humic acids

Humic acids originating from South-Moravian lignite were subjected to a comparative study with the aim to assess the alteration of their physico-chemical properties after various lignite pre-treatments. Physical modification was achieved with two organic acids, such as acetic acid and citric acid and chemical modification by nitric acid and hydrogene peroxide in various concentrations. Elemental analysis, solid-state NMR, GC–MS analysis of polyols and size exclusion chromatography were carried out for chemical–physical characterization of obtained humic acids. Their biological effect, in form of potassium and ammonium humates, was tested on maize (Zea mays) seedlings. In these tests, potassium humates achieved far better overall results than ammonium humates. Results were inter-correlated in order to appraise the influence of humic acids physical and chemical properties on biological activity. Surprisingly, fractions with the lowest molecular size (0–35 kDa) showed no correlation with bioactivity results (Pearson coefficient from 0.05 to −0.4). On the contrary, middle-sized fractions (35–175 kDa) showed highly significant positive correlation (Pearson coefficient up to 0.92) and the highest molecular-size-fractions (275–350 kDa) showed negative correlation (Pearson coefficient up to −0.75). These findings were identical for both potassium and ammonium humates. No connection was found between bioactivity of humates and polyols content which was remarkably high; it reached 150 mg per g of humic acids in the most extreme case of 5% hydrogene peroxide pre-treatment. In the final analysis, the preparation mode bore pivotal responsibility for the control of humic acids biological effect and showed the best results for potassium humates obtained from lignite pre-treated by acetic acid and by 2% hydrogen peroxide.     

Reduction of herbivore density as a tool for reduction of herbivore browsing on palatable tree species

Browsing of overabundant free-living herbivores often limits the natural as well as artificial regeneration of forest in Central-European Mountains. The aim of the study was to assess the efficiency of the extensive reductions of herbivore populations for protection of forest regeneration in preferred areas. We analysed the relationship between the intensity of shoot browsing and relative density of herbivores in viewpoint of natural regeneration of secondary mountain spruce stands with low proportion of broadleaved trees in Králicky Sněžník Reserve (Czech Republic). The distribution of seasonally migrating herbivores was established by counting faecal pellet groups (standing crop method) in growing season. The intensity of browsing of spruce, beech and rowan was assessed using the proportion of browsed shoots on individual tree sapling. Density of red deer was re-counted from the number of pellet groups and it was 15–56 individual/km². The intensity of spruce browsing was low in the whole area in all seasons. In general, the intensity of rowan and beech shoot browsing was high in the whole area. There were no correlations between deer density and browsing intensity of rowan (browsing was severe in all plots). We conclude that the natural regeneration of attractive trees and shrubs is nearly impossible in habitats where proportion of these food items is too small, even when the density of herbivores is low. Reduction of herbivores density is useful for protecting spruce and other tree species with low preference by herbivores. Forest managers should take into account the high palatability of deciduous tree species and distribution of herbivores on localities. Preference of localities is often based on grasses in the food supply. Regeneration of highly palatable tree species requires both low density of herbivores and sufficient protection of saplings.     

Botanical pesticides and their human health safety on the example of Citrus sinensis essential oil and Oulema melanopus under laboratory conditions

Biopesticides derived from plants have recently received increasing interest as an alternative to conventional chemicals suitable for integrated pest management and organic farming. In this study, Citrus sinensis (Osbeck) essential oil was tested for its potential for wheat protection against Oulema melanopus (L.). The chemical composition of the essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS). Twenty-four compounds were identified in the oil among which d-limonene was a predominant component, followed by myrcene, α-pinene, linalool, sabinene, decanal, and other minor components. Direct contact toxicity assay showed the effectiveness of the essential oil against O. melanopus larvae causing the mortality of 85% during 48 hours. The persistence study revealed high dissipation rate of the oil from treated plants, whereas concentrations lower than 0.01 g/kg were detected by GC-MS 5 min after the application of the oil, suggesting its environmental and food safety. These results, together with previous literature reports reviewed in this study, indicate the great potential of the C. sinensis essential oil for future use in crop protection against insect pests.     

A method for efficient extraction of rotifers (Rotifera) from soils

Rotifers are a group of soil animals which are not commonly quantified. The most recent data originated from soil studies focussed on nematodes and various modifications of the Baermann funnel, which is not suitable for rotifers. The present study developed a method for quantitative extraction of rotifers, which gives representative results describing rotifer populations and facilitates subsequent identification to the species level. The LC extractor recovered rotifer numbers that were two orders of magnitude higher than what was extracted from the Baermann funnel. The method involves spreading a soil sample on a plastic sieve and uses a very thin layer of cellulose submerged in distilled water in a Petri dish. The Petri dish is situated on a cooled panel and light from the top by fluorescent lamps. The temperature of the base panel which gave the best extraction results was determined experimentally to be 5 °C. Rotifers were not able to withstand any heating from the top, which drastically reduced extraction results.     

Organic matter decomposition and carbon content in soil fractions as affected by a gradient of labile carbon input to a temperate forest soil

Labile carbon (C) input to soils is expected to affect soil organic matter (SOM) decomposition and soil organic C (SOC) stocks in temperate coniferous forests. We hypothesized that the SOM...     

The Rhagidiidae (Acari: Prostigmata) in NW Lapland: Could their assemblages be climate warming monitors related to environmental and habitat patterns?

Fifteen species of Palearctic and Holarctic Rhagidiidae inhabit the polar Fennoscandian mountain birch forest and tundra, but additional taxa are expected to be discovered. Their assemblages comprise 5–10 species. Of these, Rhagidia gigas, R. diversicolor and Poecilophysis pratensis are the most abundant and widely distributed in the forested subalpine (480–600 m a.s.l.) and transitional (500–650 m a.s.l.) altitudinal zones while Poecilophysis pseudoreflexa and Rhagidia longiseta are found in the low-(600–800 m a.s.l.) and mid-(800–960 m a.s.l.), and Rhagidia parvilobata in the high alpine (960–1025 m a.s.l.) zones. Ten species of the rhagidiid mites are common in the Fennoscandian tundra as well as the alpine tundra of the Ötztal Alps, North Tyrol. Patterns of richness and diversity in this group of mites are different in different altitudinal zones in NW Lapland and the Ötztal Alps. In contrast to the Alps, no endemic species were detected in Fennoscandia. The different altitudinal niches of most common mite species overlap, but some species of mites in the subalpine forest and the high alpine zone are altitudinal vegetation belt-specific and occupy different niches. Some species of mites are rare in all altitudinal vegetation belts.Rhagidia diversicolor, R. gigas, Poecilophysis pratensis and P. pseudoreflexa exhibited sufficient abundance, habitat and elevational specificity to be useful as indicator species of the subalpine to transitional as well as the low alpine to middle alpine altitudinal zones, respectively. Rhagidia parvilobata and Poecilophysis saxonica are indicators of the high alpine zone. Abundant species from the low subalpine forested zone as well as the high alpine zone are proposed as potential monitors for direct and indirect impact of climate warming. Summit mite invaders detecting current impact of climate warming were not discovered in the high alpine zone of the Fennoscandian oroboreal tundra.     

Fluoride Anion Binding by Natural Lignite (South Moravian Deposit of Vienna Basin)

Water, Air, & Soil Pollution - Natural lignite from South Moravia was tested for the sorption of fluoride anion in concentration range from 5·10?5 to...     

Characterization of Pseudoperonospora cubensis isolates from Europe and Asia using ISSR and SRAP molecular markers

Downy mildew caused by Pseudoperonospora cubensis is a major disease of cucurbits worldwide. New genotypes of the pathogen have recently appeared in the USA, EU and Israel causing breakdown of genetic resistance, expansion of host range, and the appearance of a new A2 mating type. Seventy-eight P. cubensis isolates were collected during 1996–2011 from cucurbits fields in different regions of Turkey, Israel and the Czech Republic and genetic diversity was analysed using highly polymorphic ISSR and SRAP molecular markers. The data acquired showed remarkable genetic diversity within and among the isolates. While isolates from Turkey and Czech Republic exhibited uniform genetic background, the isolates from Israel were clearly distinguished from the others. The results may indicate on migration and/or frequent sexual reproduction of the pathogen in Israel. Moreover the selected markers can be suggested for monitoring genetic diversity within P. cubensis isolates in further studies.     

Confirmation of <Emphasis Type="Italic">Peronospora agrimoniae</Emphasis> as a distinct species

Leaves with typical symptoms of downy mildew were found on common agrimony in the Czech Republic in 2014 and 2015 and at several locations in Germany from 2010 to 2014. The causal agent of downy mildew of agrimony was often reported as Peronospora agrimoniae, but sometimes also as P. sparsa. Morphological characteristics of the pathogens found in both countries are in the range of previous works for P. agrimoniae, but also other downy mildews parasitic on Rosaceae, rendering their discrimination based on published observations difficult. For molecular identification sequencing of several loci (nrITS rDNA, cox1 and cox2) was performed. Phylogenetic analyses based on nrITS rDNA clearly separated P. agrimoniae from other Peronospora species infecting Rosaceae. Thus, considering P. agrimoniae as separate species seems justified. Two German specimens were identical to two Czech samples in both nrITS rDNA and cox1 mtDNA sequences, but differed in a single nucleotide substitution in cox2 region. To our knowledge, this is the first verified record of P. agrimoniae on common agrimony in the Czech Republic.