|
|
Ecological differences between herbs and woody plants, and evolution of the herbaceous habit
Klimeš, Adam ; Herben, Tomáš (advisor) ; Lens, Frederic (referee) ; Těšitel, Jakub (referee)
Ecological differences between herbs and woody plants, and evolution of the herbaceous habit Adam Klimeš, doctoral thesis Abstract Flowering plants (angiosperms), which make up most present-day vegetation, were originally woody. While flowering plants have repeatedly given rise to herbaceous lineages since their first appearance, we lack a clear explanation for these common evolutionary events. Freezing temperatures and drought periods have been proposed as factors which had caused huge success of the younger growth form but the evidence is very limited and not in favour of these hypotheses. In this thesis, we aimed to build the foundations of research on the evolution of herbs. We outlined new potential drivers of the evolution of herbs, suggested solutions to some methodological challenges and provided evidence about differences between herbs and woody plants relevant to the hypotheses on herb evolution. To this end, we used common garden experiments with young plants of both growth forms and global trait data from public databases which we evaluated using phylogenetic comparative techniques. Annuality of aboveground biomass and fast life-strategy of herbs are characteristics which differentiate them from woody plants and which in some conditions are expected to be behind their success. Apart from the...
|
|
|
Ecological differences between herbs and woody plants, and evolution of the herbaceous habit
Klimeš, Adam ; Herben, Tomáš (advisor) ; Lens, Frederic (referee) ; Těšitel, Jakub (referee)
Ecological differences between herbs and woody plants, and evolution of the herbaceous habit Adam Klimeš, doctoral thesis Abstract Flowering plants (angiosperms), which make up most present-day vegetation, were originally woody. While flowering plants have repeatedly given rise to herbaceous lineages since their first appearance, we lack a clear explanation for these common evolutionary events. Freezing temperatures and drought periods have been proposed as factors which had caused huge success of the younger growth form but the evidence is very limited and not in favour of these hypotheses. In this thesis, we aimed to build the foundations of research on the evolution of herbs. We outlined new potential drivers of the evolution of herbs, suggested solutions to some methodological challenges and provided evidence about differences between herbs and woody plants relevant to the hypotheses on herb evolution. To this end, we used common garden experiments with young plants of both growth forms and global trait data from public databases which we evaluated using phylogenetic comparative techniques. Annuality of aboveground biomass and fast life-strategy of herbs are characteristics which differentiate them from woody plants and which in some conditions are expected to be behind their success. Apart from the...
|
|
|
Decisions in seed reproduction in plants
Mašková, Tereza ; Herben, Tomáš (advisor) ; Thompson, Ken (referee) ; Těšitel, Jakub (referee)
Seed reproduction is a key part of the life cycle of the most plant species. It allows for the dispersal of species in space and time and, thus, significantly affects dynamics of plant populations and communities. Seed formation, germination and seedling establishment are subjected to selection pressures from the environment and lead to optimization of maternal investments (maternal care), manifested by the number of seeds and amount and composition of nutrients stored in individual seeds. The thesis aims to answer two questions: (i) whether maternal investments in terms of seed mass and seed nutrient stoichiometry is optimized according to the environmental conditions in which seedling development is expected and (ii) how nutrient availability, considering nutrients both stored in the seed by the mother plant and those available in the substrate, affects seedling growth and development. To answer the first question, we focused on interspecific comparisons of seed nutrient stoichiometry linking it with data on seed mass and species niche along gradients of nu- trient availability. We used a phylogenetically informed comparative approach to explore the ratio between phosphorus, nitrogen and nonstructural carbon in seeds from 510 wild herbaceous species. We analyzed seed nutrient stoichiometry with...
|
|
|
Dynamical pollination models
Smyčka, Jan ; Herben, Tomáš (advisor) ; Těšitel, Jakub (referee)
Dynamical pollination models (abstract) Pollination is a complex biological phenomenon which may include many interacting plant and animal species. In such a case, and especially when we are interested in effects of spatial structure, it can be helpful to use some formal approach of study, as is dynamical modelling. This thesis describes common methods for pollination modelling in space. The pollination can be divided into two consequent processes - pollinator movement and pollen carryover. Simple method of pollination movement modelling is using some random particle movement patterns, e.g. Brownian motion. This approach is useful mostly for systems with one plant species, or at large scales. More accurate, but difficult, posibility is modelling pollinators" movement through some decision making process based on their behaviour. Pollen carryover models are the necessary "translation" of pollinator movement to variables important for plants. A part of this work is also an analysis of certain pollination models. Their assumptions, predictions and modifications for not yet tackled problems are discussed.
|
|
|
Biology of the Root-Parasitic Rhinanthoid Orobanchaceae
TĚŠITEL, Jakub
Evolution, physiology and ecology of root-parasitic Rhinanthoid Orobanchaceae was investigated with special emphasis on understanding biology of hemiparasitism. The research was based on a wide range of methods including molecular hylogenetics, cultivation experiments, stable isotope analysis, electron icroscopy, geometric morphometrics and flow-cytometry.
|
|
| |
|
|
Variation in the \kur{Melampyrum sylvaticum} group
TĚŠITEL, Jakub
This study deals with morphological variation in the Melampyrum sylvaticum group (Orobanchaceae). Populations of the Hercynian Massif, Western and Eastern Carpathians were investigated using both conventional and geometric morphometric methods. Individual morphological characters were evaluated in detail. Preliminary taxonomic concept of the group is presented. Biogeographical context of detected morphological variation is discussed.
|
|
| |
guest ::
RSS feed.