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Enzyme-catalysed processes in the spoil heaps after brown coal mining: effects of site age, vegetation and seasonality
Baldrian, Petr ; Šnajdr, Jaroslav ; Valášková, Vendula ; Urbanová, Michaela ; Voříšková, Jana ; Popelářová, Petra ; Herinková, Jana ; Cajthaml, Tomáš ; Frouz, Jan
Enzyme-catalysed processes in the spoil heaps after brown coal mining are affected by site age, vegetation composition and seasonality
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Může průchod střevem žížal ovlivnit strukturu jílových minerálů: předběžné výsledky
Hušák, M. ; Frouz, Jan ; Had, J.
The effect of gut passage by three earthworm species (.i.Lumbricus rubellus, Dendrobaena octaedra, Dendrodrilus rubidus./i.) on the structure of ingested clay minerals was studied using X ray powder diffractometery. No differences were found in the peak's positions in diffraction spectra of clay spoil and clay in earthworm casts, indicating no changes in clay lamella inter-spacing. Differences were found in the peak's sizes, which seem to be caused by changes in preferential orientation of clay minerals during gut passage.
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Energetika larev tří druhů čeledi Bibionidae
Frouz, Jan ; Šustr, Vladimír ; Kalčík, Jiří
Food consumption, defecation, assimilation and production were studied in three species of bibionid larvae (.i.Bibio marci, B. pomonae, Penthetria holosericea./i.) feeding either on leaf litter or their own excrements. Assimilation efficiency of larvae feeding on leaf litter was in all species higher then assimilation efficiency of the same species feeding on their own excrements. Larvae reared on excrements also lost weight, which indicated that excrements were insufficient as an exclusive source of energy. In .i. B. marci, P. holosericea./i. the effect of temperature on assimilation efficiency was studied. In .i. P. holosericea./i. assimilation efficiency decreased with increasing temperature. This trend was not observed in .i. B. marci. B. marci./i. was fed on pure cellulose to test if cellulose can serve as the only source of energy. Mortality of larvae feeding on cellulose was significantly higher than of those feeding on leaf litter and did not differ from starving larvae.
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Vývoj půdní fauny na loukách obnovených na orné půdě: Iniciální fáze sukcesního vývoje
Tajovský, Karel ; Pižl, Václav ; Starý, Josef ; Balík, Vladimír ; Frouz, Jan ; Schlaghamerský, J. ; Háněl, Ladislav ; Rusek, Josef ; Kalčík, Jiří
The development of soil fauna assemblages (testate amoebae, nematodes, enchytraeids, earthworms, terrestrial isopods, millipedes, centipedes, collembolans, dipteran larvae) has been investigated in a -field experiment since autumn 1999. Four types of treatment were studied in plots previously managed as arable land: 1) sowing with a native seed mixture, 2) sowing of a 5 m wide central strip with native and the lateral strips with commercial seed mixture, 3) sowing of a 5 m wide central strip with native seed mixture, leaving the lateral strips to spontaneous succession, and 4) leaving to spontaneous succession (abandoned field). The observed increase of qualitative and quantitative parameters of the individual soil animal groups corresponded to the initial phase of successional development. Eurytopic and euryvalent representatives as well as epigeic species of soil micro-, meso- and macrofauna prevailed in the studied treatments during the first years of observation.
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Potential sources of polyunsaturated fatty acids for saprophagous soil invertebrates
Elhottová, Dana ; Frouz, Jan ; Krištůfek, Václav ; Lukešová, Alena ; Nováková, Alena ; Tříska, Jan
Main sources of important nutritionally compounds - polyunsaturated fatty acids (PUFA) essential in soils animal diet were compared. The highest concentration of PUFA was found in cyanobacteria (namely Antarctic strain Pseudophormidium sp.), followed by fresh litter, algae, fungi and decomposed litter. The PUFA occurrence in bacteria including actinomycetes was rare. Leaf litter is the most important source of PUFA for soil invertebrates in regards to both PUFA concentration and occurrence in soil. The stage of litter decomposition significantly affected the content of all 13 detected PUFA. The total PUFA content decreased significantly during litter decomposition. Enrichment in certain PUFA was observed in the latest stages of litter decomposition, indicating that the soil microflora improves the nutritional value of the decaying ĺitter.
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