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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...
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