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Spatial patterns of vegetation changes in nature reserve Ruda (CHKO Třeboňsko) during last 20 years
Navrátil, J. ; Navrátilová, Jana
Changes in vegetation were revealed with comparison of two vegetation maps from the years 1985 and 2004 in GIS. Vegetation types were defined on the basis of their species composition and abundance pattern in 1985 and were supervised with the same methodology in 2004. The relative cover of the vegetation types was compared in these two periods. We have detected the biggest decrease in land cover of open water bodies and the biggest increase in shrub vegetation such as mire willow scrub and those with Betula pendula in tree layer.
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Phenotypic variability in native populations of Lythrum salicaria L. across geographical gradient: between- and within-population differences
Bastlová, D. ; Květ, Jan
Variability in growth characteristics was studied in 15 native Eurasian populations of L. salicaria across the N.-S. geographical gradient in a garden tub experiment. Plant height, total plant mass and its components (dry weight of shoots, roots, lateral branches, leaves and inflorescence) and the basal stem diameter, number of lateral branches and internodes were assessed at the end of 1st season. Most of the total variability in plant height, shoot dry weight, that of lateral branches, leaves and inflorescences, basal stem diameter, leaf area, specific leaf area, flowering time and number of primary lateral branches can be explained by differences in latitude of the location of the populations' origin. But the variability in root dry weight, number of roots and number of internodes is higher between and within the populations than between the geographical locations.
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Algae and extreme environments - ecology and physiology
Elster, Josef
All photoautotrophic prokaryotes have evolved from the group Eubacteria. From fossil remains in the form of stromatolites, it has been possible to date the first prokaryotic oxyphototrophic algae (Cyanobacteria) back to almost 3,450 million years. Evolution of Eukaryotic Algae did not occur until about 700-800 million years ago. The endosymbiotic hypothesis is the most accepted theory for the origin of eukaryotic organells. Oxyphototrophic microorganisms (cyanobacteria and algae) are ubiquitous and, because of their evolutionary antiquity, are widely adapted to all the extremes related with the many changes in geological time. During the last ten years special attention has been given to study of cyanobacteria and algae in environment with extreme environment. The methodology has been steadily developing for biological-taxonomical and ecological-physiological studies.
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Ekotoxikologické biotesty v expertním systému komplexního hodnocení ekologických rizik - projekt IDRIS II
Dušek, L. ; Pavliš, P. ; Bláha, Luděk ; Maršálek, Blahoslav ; Hofman, J. ; Klimeš, D. ; Anděl, P. ; Čupr, P. ; Kohoutek, J. ; Holoubková, I.
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Screening of the health risks of biofilms using a battery of in vitro toxicity assays
Bláha, Luděk ; Babica, P. ; Sabatier, S. ; Admiraal, W. ; Maršálek, Blahoslav
Traces of microcystin-lika compounds were detected by HPCL in biofilm samples from Netherlands. Half of the tested samples had no significant effect in any of the in vitro assays, other biofilms elicicted weak inhibitory/toxic effects mostly in high concentrations, which are not environmentally relevant. Most of observed weak effect seem to be associated with oxidative stress, an important toxicologicalĺmechanisms, as detected by depletion of intracellular antioxidantĺGHS by several biofilm samples. Potential adverse effects ofĺexterne polutants, which are known to accumulate in theĺperyphyton biomass should not underestimated. Mutagenicity andĺneurotoxicity of biofilm metabolits seems to be negligible. Weekĺadverse effects of biofilm extracts detected in a batery of inĺvitro assays indicate relatively low human health risksĺassociated with biofilm toxicity.
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