|
|
Processes governing sympatric coexistence of di- and tetraploid cytotypes in primary contact zone of Knautia arvensis agg.
Hanzl, Martin ; Kolář, Filip (advisor) ; Duchoslav, Martin (referee)
Intensive cytotype screening in the primary contact zone of relict serpentine Knautia arvensis agg. revealed a striking predominance of the derivative tetraploid (81 % of subpopulations) over the diploid maternal race. Eleven mixed-ploidy subpopulations with the close spatial proximity of both cytotypes were identified. Flow cytometric analyses of almost 5 000 individuals led to discovery of two extremely rare minority cytotypes (3x, 6x). Vegetation analyses were made at two different spatial scales and in both cases confirmed the absence of distinctions in habitat preferences of cytotypes. Slight microhabitat segregation of cytotypes was however apparent at the finest spatial scales. Cytotype distribution within mixed-ploidy sites was not random. Striking patterns of cytotype clumping into cytotype uniform patches and negative spatial correlations between diploid and tetraploid individuals were apparent at all sites. Distribution of life cycle stages of diploids and tetraploids within the mixed-ploidy subpopulations were significantly different. The clonality was the most common mode of reproduction in the subpopulations of both cytotypes. Seedlings accounted for only 7 % of new plants. Significant distinctions in the plant vigour between the cytotypes were showed during the in situ comparison in...
|
|
|
Lichens on metal-rich substrates with emphasis on serpentinites
Ghlimová, Heda ; Steinová, Jana (advisor) ; Peksa, Ondřej (referee)
Serpentinite is an ultramafic rock covering about 1 % of the Earth's surface. Serpentinite contains a high content of heavy metals such as Ni, Cr, Co and, conversely, low content of major nutrients N, P, K. The high concentration of Mg reduces the availability of Ca to plants. Serpentinites are not distinguished only by their chemistry - they are also, for example, poorly thermally conductive and soils that form on the serpentine subsoil are considered infertile. This complex of properties causes the formation of so- called serpentinomorphoses in vascular plants and also promotes the development of endemism. However, these adaptations do not occur in fungi and in lichens and bryophytes they occur only partially. This bachelor thesis summarizes the basic physiological mechanisms by which myco- and photobionts ensure the survival of lichens on substrates with high content of heavy metals - it is above all extracellular absorption of metals (binding to cell wall ligands), intracellular absorption (and subsequent detoxification with metallothionein and phytochelatins), and exclusion of metals on the surface of mycobiont hyphae or on the surface of the thallus (binding to oxalates and secondary metabolites). The bachelor thesis also summarizes the morphological adaptations that occur in lichens in...
|
|
|
Population dynamics of Minuartia smejkalii
Hrušková, Karolína ; Münzbergová, Zuzana (advisor) ; Dostál, Petr (referee)
Serpentine areas in the Czech Republic form minor but important islands in the landscape with specific chemical properties such as high content of magnesium and other heavy metals. Due to this, serpentine is toxic for most plants. Increased demands on the survival and occurrence of plants lead to the emergence of serpentine specialists obligatorily specialized in these extreme habitats. Currently, serpentine areas are threatened by gradual overgrowth of sites, insufficient or poor site management and fragmentation or shrinkage of sites due to anthropogenic activities. Along with the disappearing localities, the serpentine specialists, are becoming highly endangered. Minuartia smejkalii is highly endangered serpentine specialist with an endemic occurrence in the Czech Republic with great need of its conservation. The aim of the work was to collect data on population dynamics of the species and identify habitat and climatic factors affecting population growth. We studied dynamics in all existing 7 populations during the period from 2006 to 2020 were collected. We linked these data to information on population dynamics, habitat and climatic factors and analysed them using Integral projection models (IPM). The study presents the importance of individual habitat and climatic conditions on the dynamics...
|
|
|
Processes governing sympatric coexistence of di- and tetraploid cytotypes in primary contact zone of Knautia arvensis agg.
Hanzl, Martin ; Kolář, Filip (advisor) ; Duchoslav, Martin (referee)
Intensive cytotype screening in the primary contact zone of relict serpentine Knautia arvensis agg. revealed a striking predominance of the derivative tetraploid (81 % of subpopulations) over the diploid maternal race. Eleven mixed-ploidy subpopulations with the close spatial proximity of both cytotypes were identified. Flow cytometric analyses of almost 5 000 individuals led to discovery of two extremely rare minority cytotypes (3x, 6x). Vegetation analyses were made at two different spatial scales and in both cases confirmed the absence of distinctions in habitat preferences of cytotypes. Slight microhabitat segregation of cytotypes was however apparent at the finest spatial scales. Cytotype distribution within mixed-ploidy sites was not random. Striking patterns of cytotype clumping into cytotype uniform patches and negative spatial correlations between diploid and tetraploid individuals were apparent at all sites. Distribution of life cycle stages of diploids and tetraploids within the mixed-ploidy subpopulations were significantly different. The clonality was the most common mode of reproduction in the subpopulations of both cytotypes. Seedlings accounted for only 7 % of new plants. Significant distinctions in the plant vigour between the cytotypes were showed during the in situ comparison in...
|
|
| |
guest ::
