National Repository of Grey Literature 12 records found  1 - 10next  jump to record: Search took 0.08 seconds. 
Enzymatic Studies of Organohalogen Formation By Model Compounds
Blažková, Ivona ; Tesařová, E. ; Forczek, Sándor
Research in recent years has demonstrated that halogenated organic compounds are formed in\nnature due to biotic and abiotic processes. One of the most known sources of these substances are\nfrom the reaction catalyzed by haloperoxidases which include chloroperoxidase enzyme (CPO)\nisolated from Caldariomyces fumago. CPO enzyme was incubated with chloride or bromide, in the\npresence of hydrogen peroxide and organic substrates. Experiments were conducted with three\nsubstrates (acetone, acetic acid, and glucose), and different concentrations of halides.\nMeasurement of the samples by gas chromatography with an ECD detector showed the influence\nof the substrate type and halide concentration on the formation of the organohalogen products.
Uptake and Distribution of Chlorphenols in Barley
Jíšová, Tereza ; Forczek, Sándor ; Tesařová, E.
Chlorinated phenols represent one of the most common groups of toxic industrial compounds.\nThey are resistant to biodegradation in the environment and persist for a long time. Food crops\nsuch as spring barley, are susceptible to contamination by various pesticides and organic waste,\nand these substances can then get into the plants. Uptake and distribution of 2-chlorophenol were\ninvestigated in axenic spring barley. After absorption of 14C-labelled 2-chlorophenol, the plants\nwere harvested and extracts were analyzed for 2-CP derived radioactivity. The uptake of 2-CP to\nroots and transport to leaves were confirmed. Radioactive balance was calculated for individual\nplants.
Natural Sources of Chlorinated Volatile Hydrocarbons in Spruce Forest Undergrowth
Štangelová, Pavla ; Wimmer, Zdeněk ; Tesařová, E. ; Forczek, Sándor
Chlorine as one of the most frequently occurring elements in nature, is involved in biogeochemical\ncycles. Several anthropogenic and even natural sources of volatile chlorinated hydrocarbons of\nemission is known, yet natural sources have not been explored enough. The aim of this study is to\ngather information of potential sources of chlorinated organic hydrocarbons in spruce forest\nundergrowth. Emissions of chlorinated volatile hydrocarbons of selected species of bryophytes,\nferns and fungi were measured by SMPE sampling technique and analyzed with GC-MS analysis.\nSodium chloride solution was used as a stressor to simulate increased environmental chloride load.\nTrichloromethane (chloroform) was found in most natural samples, dichloromethane,\ntetrachloroethene and tetrachloromethane were found occasionally. Increased chloride\nconcentration caused elevated emissions of trichloromethane and tetrachloromethane in some plant\nspecies.
Study of Factors Influencing the Development of "Water Bloom" in the Water Reservoir Seč
Forczek, Sándor ; Holík, Josef ; Rederer, L. ; Koza, V.
In this work, we monitored several parameters that influence the development of algal bloom on the\nwater reservoir Sec. Primarily climatic conditions belong to the monitored parameters that influence\nthe population dynamics of algae (air temperature and rainfall, incident light), temperature\nstratification of water, concentration of oxygen, concentrations of total phosphorus, phosphate,\nvarious forms of nitrogen and organic substances, turbidity and also diversity and frequency of\nphytoplankton and zooplankton species. Between 2012 and 2014 have not occurred massive algal\nblooms in the summer months, however the measured physical, chemical and biological data, can be\nused to assess the development of algal population. The population dynamic factors influencing algal\ngrowth must be understand to be able to predict formation and to attempt suppression of algal\nblooms.
Low Molecular Weight Volatile Organochlorine Compounds from Natural and Anthropogenically Influenced Ecosystems
Forczek, Sándor ; Holík, Josef ; Rederer, L. ; Ferenčík, M.
In the biogeochemical cycle of chlorine, chlorinated compounds participate in natural and\nanthropogenically influenced processes forming also compounds, which can be identical to\nchlorinated pollutants and determine by AOX (adsorbable organic halogens) method. Volatile\norganochlorines are in the center of interest due to their toxicity and possible role in degradation of\natmospheric ozone. Some volatile chlorinated hydrocarbons are both reactive and toxic, such as\nchloroform, which also has natural and anthropogenic sources and can be formed in abiotic and\nbiotic processes. In this study the occurrence of chloroform and AOX is determined in a natural\nclean environment at the Hamry water reservoir, Czech Republic. Furthermore, AOX and\nchloroform concentrations will be evaluated in correlation with meteorological and physicochemical\nconditions of water.
Seed treatment with "Trisol" stimulative products– seed germination impact
Šerá, Božena ; Hájková, M.
The seeds of barley (Hordeum vulgare L. RESPEKT) have been tested for stimulation effect of preparations originated in the BEIDEA company. Growth experiments were performed in sandy substrate, with 2 cm and 4 cm sowing, and under controlled conditions. Seed development, growth and dry weight of under- and aboveground seedlings were monitored. All preparations had a positive effect on the seed development and growth. Growth stimulatory effect is discussed in the text.
Contribution to the plasticity of barnyardgrass (Echinochloa crus-galli (L.) PB) in the saltI contamined soil
Šerá, Božena ; Gajdová, Iveta ; Nováková, Markéta
Barnyardgrass (Echinochloa crus - galli (L.) PB) is one of the major weeds, growing especially in the warmer parts of our country. This species was repeatedly found about different types of communications during a research of vegetation along roads and highways. Probably, the species has wide niche that allows it to exist even in adverse conditions, e.g. salt-contaminated area along roads. The aim of the study was to confirm that barnyardgrass can grow successfully in the salted substrate and how concentration of NaCl may inhibit its growth. Growing tests were carried out in a cultivate room on young plants which were grown in standard soil substrate with added sodium chloride (NaCl: 0.00 %, 0.12 %, 0.25%, 0.50%, 0.99 %, 1.96 %). The study found a successful growth of under- and aboveground biomass in substrates with lower concentrations of NaCl (to 0.50 %). In the substrate from concentration of 0.99 % a significant decrease of dry biomass and production of both under- and aboveground organs were found. Plant growth under different salinity stress is discussed in more detail in the text.
Different reaction of cultivars poppy seeds after nonthermal plasma treatment
Banulescu, G. ; Gajdová, Iveta ; Šerá, Božena ; Kuchtová, P. ; Šerý, M. ; Špatenka, P. ; Hnatiuc, E.
The influence of low-temperature atmospheric plasma treatment generated between the electrodes (GlidArc) on poppy seed growth was tested. Treatment times were 0 s, 180 s, 300 s, and 600 s. Working gas was air. We monitored germination and initial growth of two cultivars of poppy seeds (Papaver somniferum L., cultivars Major and Orfeus). The values of control measurements (exposure time 0 s) of the tested cultivars were different. Therefore we analysed both cultivars separately with adequate control during the data procesing. A positive influence was found mainly in the lengths of sprouts in cultivar Major (22 %, time 180 s). The number of germinated seeds was not affected by plasma treatment in both cultivars.
The growth of large crabgrass (Digitaria sanguinalis (L.) SCOP). biomass in salt contaminate soil - a greenhouse experiment
Nováková, Markéta ; Gajdová, Iveta ; Šerá, Božena
Large crabgrass (Digitaria sanguinalis (L.) SCOP.) is not registered on the list of Ellenbergs halophytic plant species. Despite it is a frequent species commonly growing along the roads on salt contaminated soils. The tests in the greenhouse were focused on finding the values of salinity in which Large crabgrass may produce biomass. Standard soil substrate contaminated by salt NaCl in the range from 0.12 % to 1.96 % was used. Tests have shown successful growth of underground and aboveground biomasses of tested plants in soil contaminated by lower concentrations of salt. Some plants despite the loss of biomass at higher concentrations were able to create generative organs with seeds. It was documented that Large crabgrass is a facultative halophyte.
Effect of various plasma sources on seed growth. Laboratory experimen in Buckwheat
Šerá, Božena ; Gajdová, Iveta ; Čermák, M. ; Gavril, B. ; Hnatiuc, E. ; Kováčik, D. ; Kříha, V. ; Sláma, J. ; Šerý, M. ; Špatenka, P.
Germination and early growth of buckwheat (Fagopyrum aesculentum) after low-temperature plasma discharge treatment in air gas generated in various apparatus were tested. Three pretreatment times were used: 180 s, 300 s and 600 s. Number of germinating achene, length and weight of sprouts were measured. The data was analysed with two-way ANOVA. A significant influence of the type of plasma apparatus, time of exposure and combination of both factors were found. The positive effect on germination and early growth was observed after application of GlidArc plasma. The opposite effect of PDBV apparatus, which is characterized by plasma with a high power density, was observed. Shorter pre-treatment times for this apparatus must be therefore used.

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