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251.
Tephroseris longifolia subsp. moravica is an endemic endangered taxon of European importance. Within the nine recently known populations it occurs in very specific
site conditions of ecotone habitats. In our contribution, we try to quantify its realized niche with regard to the measured
components of its biotic and abiotic environment. The main aim was to assess the importance of spatial environmental variation
on taxon occurrence and performance and to relate the obtained ecological information to data on taxon abundance and demography.
Possible reasons of taxon rarity are discussed, too. Comparison of plot pairs indicated that plots containing the taxon had
deeper soil and higher soil Na and Mg contents than plots without it. They also contained higher number of species, especially
forbs. Several soil parameters were positively correlated with taxon size and density while light parameters played minor
role. Negative correlations between cover of vascular plants, especially grasses and taxon size and density suggest its reduced
competitive ability. Vascular plant-based ecological indicator values were set for light (6), temperature (5), continentality
(4), moisture (5), soil reaction (7) and nutrients (5). The studied sites differed in topography, soil characteristics (pH,
soil Na, K, Ca, P and NH4) and cover of herb litter. Size of taxon populations was negatively related to their finite rate of increase which varied
between 1.25 and 2.04 and was most sensitive to demographic parameters related to growth. We conclude, that the studied taxon
is not strictly stenotopic as the ranges of several environmental variables were rather wide. We suppose, that the narrow
limits of recent taxon occurrence are consequences of its low competitive ability and demographic processes related to germination
and seedling establishment. The differing requirements of its ontogenetic stages (seedlings and generative individuals) may
define the final limits of its small-scale distribution. 相似文献
252.
Katarína Jurdíková Jana Kulichová Helena Bestová Frederik Leliaert Pavel Škaloud 《The Journal of eukaryotic microbiology》2014,61(5):509-519
Freshwater green microalgae are diverse and widely distributed across the globe, yet the population structuring of these organisms is poorly understood. We assessed the degree of genetic diversity and differentiation of the desmid species, Micrasterias rotata. First, we compared the sequences of four nuclear regions (actin, gapC1, gapC2, and oee1) in 25 strains and selected the gapC1 and actin regions as the most appropriate markers for population structure assessment in this species. Population genetic structure was subsequently analyzed, based on seven populations from the Czech Republic and Ireland. Hudson's Snn statistics indicated that nearest‐neighbor sequences occurred significantly more frequently within geographical populations than within the wider panmictic population. Moreover, Irish populations consistently showed higher genetic diversity than the Czech samples. These results are in accordance with the unbalanced distribution of alleles in many land plant species; however, the large genetic diversity in M. rotata differs from levels of genetic diversity found in most land plants. 相似文献
253.
Liptáková Ľubica Demecsová Loriana Valentovičová Katarína Zelinová Veronika Tamás Ladislav 《Plant molecular biology》2022,108(1-2):145-155
Plant Molecular Biology - Already a short-term Cd treatment induces changes in gene expression in barley root tips via IAA and ROS signaling during mild and severe Cd stress, respectively. Even a... 相似文献
254.
Jana Harichová Edita Karelová Katarína Chovanová Tatjana Stojnev Miloslava Prokšová Ján Brindza Peter Brindza Dezider Tóth Domenico Pangallo Peter Ferianc 《Biologia》2006,61(6):663-670
This research work was oriented to outlining the diversity of Gram-negative culturable portion of the bacterial community
in three fruit plants rhizosphere. Rhizosphere samples were taken from European chestnut (Castanea sativa Mill), true service tree (Sorbus domestica L.) and cornelian cherry (Cornus mas L.) plants. Experiments were conducted for three years during the vegetation period, and the bacterial community structure
was assessed with cultivation-dependent approach. Many Gram-negative isolates (n = 251) from the rhizosphere survived sub culturing and were identified by biochemical tests. A total of 57 species belonging
to 29 genera were identified and assigned to four broad taxonomic groups (Bacteroidetes, Alpha-, Beta- and Gamma-proteobacteria). Several specific bacterial cluster communities were identified inside all the three rhizospheres. Most of the species belonged
to the genera Moraxella, Pseudomonas, Pantoea, Enterobacter and Acinetobacter. In addition, while, using the plate count analysis, large discrepancies in numbers among physiological groups of bacteria
cultured from three rhizosphere samples have not been revealed, more expressive distinctions among bacterial populations were
obtained concerning the relative abundance of different genera, different taxonomic groups as well as different diversity
indices. Furthermore, the number of cultured bacteria and their taxonomic distribution in the rhizosphere of all three plants
changed not only explicitly during vegetation period but continually during the three years of investigation. It seems that
rhizosphere bacterial populations of each plant are under the influence of the specific root-released materials. 相似文献
255.
The aim of this study was to evaluate the effect of transgenic alfalfa (Medicago sativa L.) plants, in comparison to their non-transgenic counterpart, on the density and physiological profiles of aerobic bacteria
in the rhizosphere. Plants of transgenic alfalfa expressing the AMVcp-s gene coding for Alfalfa Mosaic Virus coat protein were cultivated in a climatic chamber. Two methods were used to determine
the microbial diversity in rhizospheres of transgenic plants. First, the cultivation-dependent plating method, based on the
determination of the density of colony-forming bacteria, and second, a biochemical method using the Biolog™ system, based
on the utilization of different carbon sources by soil microorganisms. Statistically significant differences in densities
of rhizospheric bacteria between transgenic and non-transgenic alfalfa clones were observed in ammonifying bacteria (GTL4/404-1),
cellulolytic bacteria (GTL4/404-1, GTL4/402-2, A5-3-3), rhizobial bacteria (GTL4/402-2), denitrifying bacteria (A5-3-3) and
Azotobacter spp. (GTL4/402-2). The highest values of substrate utilization by microbial communities and average respiration of C-sources
were determined in non-transgenic alfalfa plants of the isogenic line SE/22-GT2. Carbohydrates, carboxylic acids and amino-acids
were the most utilized carbon substrates by both Gram-negative and Gram-positive bacteria. Both, the community metabolic diversity
and the utilization of C-sources increased in all alfalfa lines with culture time and regardless of transgenic or non-transgenic
nature of lines. 相似文献