|
|
Vliv kultivačních podmínek na kryoprezervaci půdních řas a sinic
Lukešová, Alena
Fundamental principles of both conservative and vitrification cryopreservation methods are presented, and factors affecting cryopreservation of algae and cyanobacteria are summarized. These factors include factors connected with the cryopreservation process itself as well as factors connected with pre- and post-cryopreservation manipulation with samples. Attention is paid to cultivation conditions, mainly to the temperature in the context of application of cold acclimation before cryopreservation. Both literature data and our experience indicate that the response of soil algae and cyanobacteria to particular factors is species or strain specific and optimization of condition can enhance post-cryopreservation viability of cryopreservation recalcitrant strain.
|
|
|
Změny ve společenstvech půdní mikroflóry a mesofauny během rozkladu listového opadu ve dvou vegetačních zónách - litter bag experiment
Jirout, Jiří ; Petrásek, Jiří ; Čápová, Lenka ; Farská, Jitka ; Jínová, Kristýna ; Rusek, Josef ; Krištůfek, Václav ; Elhottová, Dana ; Starý, Josef ; Nováková, Alena
The hypothesis, whether autochthonous species of soil biota are able to decompose litter from lower vegetation zones in higher zones, was tested by field trial. Litterbags with litter of beech (.i.Fagus sylvatica./i. L.) and/or oak (.i.Quercus robur./i. L.) were exposed in beech and spruce forest on the mountain Kleť (Protected Landscape Area Blanský les). Litterbags layout simulated vegetation zones shift to the higher altitude induced by global warming. There were used litterbags with three different mesh size (42 µm, 0,5 mm, 2 mm) for exclusion of certain parts of edaphon. Several changes of soil bacteria and micromycetes, oribatid mites, springtails and gamasid mites were studied during two years of exposition. There were exposed 480 litterbags at the start of the experiment (November 2002). After 2, 4, 6, 12, 24 months of exposition parts of all litterbags were recovered. Immediately after the sampling litter pH(KCl), moisture and mass loss were measured.
|
|
|
Mikroskopické houby v půdě, listovém opadu, exkrementech a střevním traktu .i.Dendrobaena mrazeki./i. (Lumbricidae)
Nováková, Alena ; Pižl, Václav
Species diversity and quantitative parameters (mycelial length, CFU counts) of saprotrophic microfungi assemblages were studied in the intestine and casts of .i.D. mrazeki./i. and compared with those in soil and litter at four plots of a thermophilous oak forest in Southern Moravia (Czech Republic) in 2004. Soil dilution plate method and soil washing technique and three isolation media were used for the isolation of fungi. Differences in species number and composition of fungi assemblages were found both among individual substrates studied and between the results of different isolation methods. Number of species isolated by the soil dilution plate method was higher in earthworm casts than in soil, however, the opposite results were obtained using soil washing technique. CFU counts reached the highest values in leaf litter.
|
|
|
Emissions of greenhouse gases (N2O and CO2) from pasture soil as a result of activity of soil microbial community - preliminary results
Šimek, Miloslav ; Hynšt, Jaroslav ; Brůček, Petr ; Čuhel, Jiří
Cattle overwintering area was shown an important point source of N2O and CO2. The emissions of N2O were mostly directly related to the rate of animal impact as the greatest fluxes of N2O and the highest total cumulative N2O emissions as well were found at the most impacted site. The fluxes of N2O were however very variable in time and most of N2O was emitted during several short events in spring or in winter. Laboratory experiments suggested that total amount of nitrogen escaping from soil from impacted sites is much greater than indicated by field measurements of N2O fluxes and molecular nitrogen (N2) was shown as the main nitrogen gas. It is hypothesized that soil pH is a crucial soil factor controlling the mole fraction of N2O: under slightly alkaline conditions in severely impacted soils, denitrification is completed and most of nitrogen escapes from the soil as N2; under more acidic conditions, however, the activity of nitrous oxide reductase is partly reduced.
|
|
|
Dynamics of N2O emissions after C and N amendments of soil at the cattle overwintering area
Hynšt, Jaroslav ; Brůček, Petr ; Čuhel, Jiří ; Šimek, Miloslav
Field experiments were carried out at the cattle overwintering area in South Bohemia, Czech Republic, focused on the emissions of N2O after soil amendments with nitrate and glucose. Emissions were estimated using a permanent static chamber technique. Nitrate and glucose amendments caused very sharp increases of N2O fluxes, which however diminished after 2-3 days. Total amount of N2O escaping the soil was related to the amount of N and C added, and was calculated to 1-15 kg N.ha-1 (0.2-3% of N applied). Emissions were heterogeneous, which is shown by great differences among the individual chambers. Emissions were variable in time and very probably were controlled by temperature, as they approximately followed the air and surface soil temperature patterns. Despite the timing of amendment application, peaks of emissions were always determined 6 hours after the amendments.
|
guest ::
