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As sedentary organisms, plants have to develop many mechanisms to cope with disturbance events, which are common in most habitats, and occur over a range of intensities and frequencies. Some species are able to tolerate disturbance events by rebuilding their lost parts via resprouting from adventitive or axillary buds, and/or resist disturbances by creating various defense mechanisms. This thesis aims to reveal some aspects of tolerance and resistance of herbs to disturbance on the level of plant individuals as well as entire plant communities.

The ongoing climate crisis represents a growing threat for plants and other organisms. However, how and if plants will be able to adapt to future environmental conditions is still debated. One of the most powerful mechanisms allowing plants to tackle the changing climate is phenotypic plasticity, which can be regulated by epigenetic mechanisms. Environmentally induced epigenetic variation mediating phenotypic plasticity might be heritable across (a)sexual generations, thus potentially enabling rapid adaptation to climate change. Here, we assessed whether epigenetic mechanisms, DNA methylation in particular, enable for local adaptation and response to increased and/or decreased temperature of natural populations of a clonal plant, Fragaria vesca (wild strawberry). We collected ramets from three populations along a temperature gradient in each of three countries covering the southern (Italy), central (Czechia), and northern (Norway) edges of the native European range of F. vesca. After clonal propagation and alteration of DNA methylation status of half of the plants via 5-azacytidine, we reciprocally transplanted clones to their home locality and to the other two climatically distinct localities within the country of their origin. At the end of the growing season, we recorded survival and aboveground biomass as fitness estimates. We found evidence for local adaptation in intermediate and cold populations in Italy and maladaptation of plants of the warmest populations in all countries. Plants treated with 5-azacytidine showed either better or worse performance in their local conditions than untreated plants. Application of 5-azacytidine also affected plant response to changed climatic conditions when transplanted to the colder or warmer locality than was their origin, and the response was, however, country-specific. We conclude that the increasing temperature will probably be the limiting factor determining F. vesca survival and distribution. DNA methylation may contribute to local adaptation and response to climatic change in natural ecosystems; however, its role may depend on the specific environmental conditions. Since adaptation mediated by epigenetic variation may occur faster than via natural selection on genetic variants, epigenetic adaptation might to some degree help plants in keeping up with the ongoing environmental crisis.

A growing body of literature suggests that epigenetic variation might contribute to local adaptation of natural plant populations. Epigenetic mechanisms, such as DNA methylation, can in fact quickly alter phenotypes in response to environmental changes. Furthermore, these changes can be inherited across several generations (especially clonal), suggesting that DNA methylation may enable heritable phenotypic variation and eventually contribute to adaptation. However, it is still unclear whether epigenetic mechanisms can have an adaptive potential in plants, or in other words, whether they present variation among natural populations, are inherited across generations and have fitness effects. During my PhD project, together with my co-authors, I tested these conditions on several natural populations of two non-model clonal plant species, the wild strawberry (Fragaria vesca) and the black poplar (Populus nigra). To do so, I used the current gold standard for DNA methylation analysis (Whole Genome Bisulfite Sequencing), which allowed me to characterize the genome-wide DNA methylation level of individual plants at the single base-resolution. For both species, I found extensive DNA methylation diversity among populations, which was partially affected by the natural climatic conditions of the populations...

Because of their low genetic variability and limited ability to respond to the changing environment, clonal plants are often considered an evolutionary dead end. On the other hand, numerous recent studies showed that clonal plants can react to the changing environment through epigenetic mechanisms, especially through DNA methylation. Moreover, epigenetic information in clonal plants can be transferred to future generations (so-called transgenerational memory). As a result, epigenetics can ensure better fitness of the next clonal generation. The aim of this work is to summarize the knowledge about the role of epigenetic variability in the life of clonal plants performing limited genetic variability. Key words: epigenetics, DNA methylation, epigenetics variation, clonal plants, transgeneration memory

The aim of this study is to provide a further insight into influence of environment on clonal plants. The study focuses particularly on effects of fertilization level and light availability on production and growth of clonal organs. Three experiments were carried out within the study, targeted to elicit influence of these environmental conditions or clonal interactions on six species of clonal plants. Interspecies dependencies on these conditions was compared, regarding habitat occurrence of these species. A comparison was made also between species producing rhizomes and stolons. The experiments revealed that five of six studied species show significant relationship among at least one environmental condition and parameters of clonal reproduction. Most of the species showed higher elongation and production of clonal organs in relation to fertilization level. On the contrary, only three species reacted significantly to the light availability level by alternation of at least one parameter of clonal reproduction and the light availability level affected each species differently. A strong influence on production and elongation of clonal organs had also a size of a plant. There was not found significant difference in influence of environmental conditions on clonal reproduction among plant families. It...

Plants have evolved various defence mechanisms depending on the ecological context of their environment. The first part of this review summarises possibilities of plant defence. All types of defence are energy intensive. In most cases, a plant chooses between two strategies: being 'fast growing and non- poisonous' or being 'slowly growing and poisonous'. The next part of the review focuses on chemical defence of the Asterace family. Secondary metabolites of the Compositae are characterized by isoprenoids which cause bitterness of essential oils and latex. This review is mainly about sesquiterpene lactones due to their great role in plant - herbivore interactions and their pharmaceutical potential. Powered by TCPDF (www.tcpdf.org)