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Photobiont plurality in lichen thalli
Dědková, Kamila ; Steinová, Jana (advisor) ; Vančurová, Lucie (referee)
Photobiont plurality refers to the presence of multiple photobionts within a single lichen thallus. This phenomenon was described at the end of the last century but has received deeper attention in the last decade. The available literature on this topic is limited. This bachelor thesis summarizes all the important findings published on plurality to date. The most common photobionts coexisting in a thallus are algae of the genus Trebouxia, but other algae and cyanobacteria more or less phylogenetically related may also coexist together. Thallus with multiple photobionts is formed either at the beginning by the association of hyphae with several photobionts at once (horizontal transport) or by the acquisition of additional photobionts during life (vertical transport). The most important factors affecting the cooccurrence of multiple photobionts in a single thallus are probably the specificity and selectivity of mycobionts and local environmental conditions. The plurality of photobionts has been found in more than fifty lichen species. Many important findings have been described in a model lichen Ramalina farinacea. Its coexisting photobionts differ in responses to several environmental, mostly stress conditions, suggesting that the presence of multiple photobionts in a thallus may provide an...
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Functional traits and functional diversity in lichens
Kolenská, Lucie ; Malíček, Jiří (advisor) ; Vondrák, Jan (referee)
Functional traits are a discussed topic across disciplines and articles with lichens are published as well. Traits are the attributes that define the organism from morphological features through anatomy to the physiology of the individual, including interaction in environmental and environmental influences. The most frequently studied functional trait of lichens is the type of thallus. Another commonly studied trait is the type of photobiont, where the presence of algae Trentepohlia is negatively affected by frost and because of this its number decreases with increasing altitude. Another functional trait of lichens which is studied is reproduction, and also secondary metabolites, which protect lichens, for example, against UV light or herbivores. Functional traits together form functional diversity, which is another way how to measure diversity on a planet where the most diverse ecosystem is not always the one with the highest number of species. Functional diversity indices then can reveal unique communities that should be protected. However, neither the definitions nor the calculation of functional diversity are exatly specified, we use different indices. The Rao index of quadratic entropy is most often used for lichens. Keywords indices, lichenized fungi, mycobiont, photobiont, thallus
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