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Anabaena - Phenotypic and genotypic diversity of planktonic strains in fishponds and reservoirs of the Czech Republic
ZAPOMĚLOVÁ, Eliška
Morphological diversity of 61 Anabaena populations of 13 morphospecies was described under the field conditions of Czech fishponds and reservoirs. Polyphasic approach was then applied in classification of 45 clonal strains isolated from those populations. Detailed morphological analyses were performed and partial 16S rRNA gene sequences were obtained for 33 of the strains, and secondary metabolite production was evaluated in 20 strains. Plasticity of morphological characteristics under varied conditions of light, temperature, nitrogen and phosphorus was studied in selected strains, as well as their temperature and light growth requirements. The results were then discussed with respect to the delimitation of single Anabaena morphospecies. A new genus Sphaerospermum was defined for the morphospecies Anabaena kisseleviana, A. reniformis and Aphanizomenon aphanizomenoides, whose phenotypic and genotypic features differed considerably from all other Anabaena morphospecies. Unique information was provided on the occurrence and distribution of A. reniformis and Aph. aphanizomenoides in the Czech Republic.
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Methods of the separation of the base flow and trends of nitrogen concentrations in this base flow
MAIEROVÁ, Monika
This Bachelor thesis is aimed to clarify the hydrological cycle, hydrological balance, groundwater hydrology, the selected basic baseflow separation methods of comparing them and last but not least, nitrogen cycle, nitrogen, nitrates, ammonia nitrogen and nitrogen in groundwater. In the work there is also closely analyzed the total, surface and subsurface outflow and the detailed division. The methods of the groundwater baseflow separation are described with regard to content of nitrogen compounds., which currently create the most common type of pollution of groundwater used as drinking sources.
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Metabolic rhythms of unicellular, nitrogen fixing cyanobacteria and possible interplay with modeled KaiABC circadian oscillator
Červený, Jan ; Nedbal, Ladislav
Circadian clocks of living organisms provide evolutionary advantage and make living in dynamic environment more efficient. The clocks affect human lives and health as well as control the simplest organisms such as prokaryotic cyanobacteria. The cyanobacteria represent an excellent model that is amendable to a multitude of genetic, biochemical, and biophysical methods. The cyanobacterium, Cyanothece sp. ATCC 51142 relies on the circadian clock to permit, in the same cell, anoxygenic nitrogen fixation at night and oxygenic photosynthesis during solar day. We measured real-time, in-situ photosynthetic and respiratory activities as well as the culture growth under light forcing conditions and also under constant light, i.e. free-running mode. Interestingly, the experiments show a strong 24h-period dynamic pattern that is replaced by apparent 12h-period in free running mode. The 24h-pattern does not change significantly when changing the light/dark ratio from 16hL/8hD to 12hL/12hD and 8hL/16hD. Furthermore, we tried to elucidate connection between these metabolic rhythms and known structure of KaiABC circadian oscillator by means of mathematical modeling. One of simulation results show a strong correlation between the presumed catabolic event indicated by significant peak in respiratory activity, and simulated dynamics of KaiB4 complex in modeled circadian pacemaker. A causal relationship between these 2 events is suggested because KaiB4 facilitates dephosphorylation of KaiC6 hexamer, which is known to signal upcoming dark period.
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Monitoring and evaluation of nitrate content in root crops and cole crops distributed at retail outlets.
NOVÁKOVÁ, Jana
The object of this research was follow up the cumulation of nitrates in individual kinds of vegetables. Analysed was 240 samples of root crops, cole crops and potatoes distributed in the trade network in Humpolec in the years 2008 - 2010. The measurement results show that all the vegetables went beyond the nitrate permitted limit, according to a law n. 53/2002. The most frequently it was in potatoe samples (50 % samples). The next was a carrot (27 %), kohlrabi (25 %), broccoli (24 %) and celery (17 %). From aspect cumulation of nitrates is parsley unchallenged kind of vegetable. Permitted limit was transcendent in 10 % about less than 1 %. The origin of the vegetables was detected as well. Czech republic had the worst results (52,5 %) because of the high nitrate concentration in potatoes. It is grown by a domestic growers. Spain had 20 % in broccoli and kohlrabi. It is imported to our market. Although the high nitrate concentration in some vegetable samples the vegetable influence the human health in a positive way and it doesn?t make health hazard.
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Arbuscular mycorrhizal symbiosis of herbaceous invasive neophytes in the Czech Republic
ŠTAJEROVÁ, Kateřina
I have studied arbuscular mycorrhizal symbiosis of 44 herbaceous invasive neophytes occuring in the Czech Republic. My results show that about 70% of the examined species are capable to form symbiotic association with arbuscular mycorrhizal fungi (AMF) in the field. To my knowledge, mycorrhizal status of 23 invasive species is reported here for the first time. I predicted, based on the hypothesis of Urcelay & Díaz (2003), that the intensity of AMF in the roots of invasive species will be correlated with that of the native dominant species of invaded plant community, but collected data did not support this hypothesis. In addition, the effects of habitat and community characteristics on the intensity of AMF colonization of the invasive species{\crq} roots were tested. My results show that, at the within-species level, plants in the habitats with higher light and temperature conditions have less colonized roots whereas intensity of mycorrhizal colonization increases with habitat moisture. At the among-species level, invasive species occurring in the habitats with elevated nitrogen availability have higher mycorrhizal colonization of their roots. The effect of nitrogen availability is revealed at the among-species level and stays significant even after phylogenetic correction, suggesting this is an evolutionary adaptation rather than a phenotypic plasticity.
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Species palatability, life history traits and litter decomposition rate
PÁLKOVÁ, Kateřina
Palatability of 20 meadow plant species was assessed in the slug grazing experiment conducted. Monocots exhibited significantly lower palatability than dicots. Litter decomposition rate was assessed in the field litter-bag test. Linear regression analysis was performed to answer the main question whether species palatability is related to litter decomposition rate and whether it is determined by the carbon or nitrogen content. Phylogenetically independent contrasts were used to eliminate correlated phylogeny effect. Regression trees were used to detect the effect of species traits on species palatability and litter decomposition rate.
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