|
|
Plant adaptation to climate change
Koláříková, Veronika ; Münzbergová, Zuzana (advisor) ; Sklenář, Petr (referee)
Climate change represents important selective force for plants. They have to deal with this change otherwise they are facing the risk of extinction. Understanding the mechanism which plants use to avoid the risk is essential for effective conservation of biodiversity. The climate change can exceed the tolerance of plants to abiotic factors. The plants can react to the changes by migration, phenotypic plasticity, evolutionary adaption or by a combination of these strategies. Phenotypic plasticity and evolutionary adaption are manifested by a change of physiology, morphology and/or phenology of plants. This work summarizes the findings of these ecological and evolutionary strategies and also presents methods used for studying species response to climate change. Powered by TCPDF (www.tcpdf.org)
|
|
| |
|
|
Evolutionary processes underlying plant diversification in the tropical Andean highlands
Aparicio Vásquez, Diana Libeth ; Sklenář, Petr (advisor) ; Hughes, Colin (referee) ; Šmarda, Petr (referee)
The highlands in the northern Andes, which are known as the páramo, are recognized worldwide for their unique and species-rich flora. Many páramo plant groups underwent radiations, which have been shown to be very recent and outstandingly fast. These radiations have usually been linked to (1) the uplift of the northern Andes, which provided new ecological opportunities in the highlands that originated in this process, (2) Quaternary climate change that produced range shifts of the páramo, resulting in periods of páramo contraction and isolation, during cold periods, and periods of páramo expansion and connection, during warm periods (3) the Andean physiographical and ecological heterogeneity, which provides extent oppornuties for isolation and for ecological divergence. In spite of increasing research efforts to understand the evolution of the páramo flora, the actual processes underlying species diversification remain unclear. The main aim of this thesis is to contribute to the understanding of these processes. We use three different approaches in two different study systems: (1) A population genetics approach, which remains rare among páramo plant studies, focuses on three páramo Lupinus species (Lupinus alopecuroides, L. nubigenus, L. microphyllus). These species belong to one of the best...
|
|
| |
|
|
Spatial distribution of vegetation species on the earth hummocks on Mt. Keprník and Mt. Praděd in the Hrubý Jeseník Mts.
Kodríková, Anna ; Křížek, Marek (advisor) ; Sklenář, Petr (referee)
This thesis focuses on spatial distribution of vegetation species on the earth hummocks on Mt. Keprník and Mt. Praděd in the Hrubý Jeseník Mts., the relationship of the spatial distribution of vegetation to windward and leeward effect, and also on the morphological characteristics of earth hummocks. The windward and leeward effect was studied not only on the earth hummocks themselves, but also in the whole study area. The succession of vegetation, which reflects an activity of earth hummock and a level of their development, was also concerned. Earth hummocks are nonsorted patterned ground types. Vegetation on earth hummocks affects not only their formation, but also their shape and internal characteristics. Further,vegetation reflects certain properties of earth hummocks (moisture, soil characteristics etc.), and also ecological conditions which affect earth hummocks (wind impact, distribution of snow cover etc). Each studied earth hummock was first measured (length, width and height) in the field and then was divided into quadrants according to the efect of wind (windward quadrant oriented SW, windward quadrant oriented NE, and two remaining quadrants oriented NE, NW) in which phytocenological surveys were carried out. The results show that the vegetation on earth hummocks is strongly efected by...
|
|
|
Ecophysiology of peat bog ericoid subshrubs - freezing resistance and water relations
Daněk, Michal ; Sklenář, Petr (advisor) ; Hájek, Tomáš (referee)
The seasonal changes in freezing resistance and water relations in four dwarf shrub species of Ericaceae family: Vaccinium vitis-idaea, V. myrtillus, V. uliginosum and Oxycoccus palustris in two study areas differing in altitude were studied in this work. To establish the freezing resistance, the plants were sampled eight times, to determine parameters of the water relations, the plants were sampled six times during the growing season of 2009. For the freezing resistance examination, ice nucleation temperature (exotherm) and 50 per cent lethal temperature (LT50) were found. The water relations were described using the parameters derived from the pressure-volume curves: osmotic potential at full turgor, osmotic potential at zero turgor, cytoplasmic water fraction, relative water content at turgor loss and bulk modulus of elasticity. An important seasonal variability in the freezing resistance was found. The highest levels of the freezing resistance were reached in the spring and in the autumn, the lowest levels were found in the summer. There were also changes in the used mechanisms of the freezing resistance - for most of the year, the plants were tolerant, they showed the avoidance mechanism only in the summer. The seasonal changes in the water relation parameter were less unambiguous. The most of...
|
|
|
Factors determining the alpine treeline
Oľhava, Rastislav ; Sklenář, Petr (advisor) ; Treml, Václav (referee)
The alpine treeline is a global phenomenon which represents sudden change between two significantly different vegetation types: mountain forest and low-stature alpine vegetation. The primary climatic factor that determines its position seems to be the temperature. We summarize the results that describe the relation between temperature and the altitudinal position of the treeline and search for a general formula that would determine its position. There are two hypotheses which try to explain what is the main limiting factor above tre- eline: C-limitation and growth-limitation. The first one claims trees are limited by carbon shortage, while the latter one favours low-temperature limitation of tissue formation al- though the carbon income is sufficient. This thesis provides a summary of the arguments for each of them and describes the state of knowledge on this matter.
|
|
|
Plant-Animal Interactions in an Inselberg Ecosystem: The Effect on Reproduction of Selected Species
Vlasáková, Blanka ; Sklenář, Petr (advisor) ; Porembski, Stefan (referee) ; Jersáková, Jana (referee)
Conclusions This thesis provides detailed insight into plant-animal relationships that are involved in reproduction of inselberg species. The results are interpreted in relation to the ecosystem functioning and they also contribute to the general knowledge on specialization in plant-animal interactions (Chapter 2 and 3), floral resources (Chapter 2, 3, and 5), pollinators' attraction (Chapter 2), relations between diaspore's characteristics and animal dispersal (Chapter 4), and conflicts among plant life stages that follow ovule fertilization (Chapter 4). As Clusia aff. sellowiana dominates the shrub vegetation, the study on its reproduction is the initial step to understanding the dynamics of the shrub patches and potential succession on the inselberg. The nocturnal pollination system of Clusia aff. sellowiana bears unusual characteristics and signs of specialization. Only one pollinator species, a cockroach Amazonina platystylata, was recorded and this species is apparently sensitive to olfactory attraction cues emitted by the flowers. This is the first evidence of pollination system that involves cockroaches as pollinators and is to some degree specialized. Clusia aff. sellowiana is dispersed by small birds. Because its diasporas are consumed by birds and there is a time lag before they are deposited,...
|
|
| |
|
|
The importance of the arrangement of flowers in the inflorescence on the plant reproductive success
Chvojková, Karolína ; Štenc, Jakub (advisor) ; Sklenář, Petr (referee)
Inflorescence and its properties have a fundamental influence on the pollinating behavior of pollinators, which can affect the resulting reproductive success of plants. Clustering of more flowers in the inflorescence is an advantage for plants due to the diversification of pollen sources and greater visual supply, which can attract more pollinators and thus increase the chance of pollen transfer to other individuals and ensure genetic variability of the offspring. The disadvantage of multiple flowers in one inflorescence may be both an increase in energy requirements for the formation and maintenance of multiple flowers and an increased risk of geitonogamy. Plants prevent geitonogamy within the inflorescence by various adaptations. The aim of this work is to evaluate the effect of inflorescence arrangement on successful plant reproduction. When studying the arrangement of flowers in the inflorescence, it is necessary to take into count not only their morphology, i.e. the shape, number, size and arrangement of flowers, but also other functional properties in the form of genitals, sterility and rewards. The resulting effect of flower arrangement on the reproductive success of plants also depends on the vectors that transfer pollen, in this case especially insect pollinators, which are affected by...
|
guest ::
RSS feed.