National Repository of Grey Literature 28 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Interaction between herbivores and pathogens on plant
Nerandžičová, Denisa ; Koubek, Tomáš (advisor) ; Weiser, Martin (referee)
Plants are often simultaneously attacked by herbivores and phytopathogens and interactions between these antagonists have consequences for their fitness and also for plant defense. Plant disease leads to modification of plant biochemical processes which alter the host plant choice by herbivores and the availability of their nutritional resources and it induces changes in plant defense responses. Herbivores facilitate the development of plant diseases and their transmission from plant to plant. Mutual antagonism between jasmonic acid and salicylic acid signaling pathways is believed to be the main cause behind the effects of the interactions. However, according to diverse outcomes from current studies, this theory seems to be oversimplified and thus inapplicable. Effects of the interactions are driven by many more factors, from which the species specificity plays the main role. Despite this, current literature accumulates evidence that these interactions do not multiply damage from the double attack. Subsequent damage is usually more severe within individual organs but is much less severe for overall plant fitness due to the plant's ability to compensate for the losses.
The effect of pathogens on invasive plants
Sládečková, Julie ; Koubek, Tomáš (advisor) ; Čuda, Jan (referee)
Invasive plants can destroy entire ecosystems, reduce biodiversity and thus threaten the environment. Number of invasive species is increasing and so their negative impact on the environment. Various reasons can be behind the emergence of invasions, one of them is, for example, escaping from natural enemies. This can make the plant more competitive, have greater reproductive potential and spread better. However, if natural enemies are added to the new area, the number of invasive plants can be regulated. This is the principle of biocontrol, which is a method used to reducing the magnitude of invasions and their consequences. This method has almost no negative impacts on the environment, unlike chemical and mechanical methods of plant removal. Biocontrol has a long-term effect and therefore is also cheaper. However, when biocontrol is used, there is a certain risk that non-target plant species will be affected or that it will not be effective enough. Pathogens are also used as biocontrol agents because they are more specialized than herbivores, so the risk for non-target plants is lower. The aim of this thesis is to compare biological control with other methods used to removing invasive plants and to summarize the most significant positives and negatives of using fungal pathogens in plant biocontrol.
Population biology of Dianthus carthusianorum in populations infested by anther-smut
Kasner, Marek ; Koubek, Tomáš (advisor) ; Dostálek, Tomáš (referee)
Anther-smuts (Microbotryum violaceum s. l.) are systemic plant pathogens sterilizing their hosts, thus decreasing its reproduction on the expense of own sporulation. The spores are, consequently, transmitted by pollinator vectors and deposited on healthy flowers. This thesis contributes novel, to date missing information about population-level impact of the pathogen that severely influences its host fitness by examining a relatively new model species Dianthus carthusianorum. Additionally, it considers the effect of pre-dispersal seed predators (caterpillars of Hadena moths). Deterministic matrix models were used for the quantification of the effects of both plant antagonists. Notably, the use of such type of models is rather unique in population biology of plant pathogens. The research was conducted in three localities in Střední Povltaví area in years 2018-2021 when the demographic data were collected, reflecting the whole plant life cycle. During the annual censuses we gathered not only the information about the vital rates of the plants (growth, reproduction, infections...) but also selected size characteristics of permanently marked plants were measured to explore possible changes induced by a systemic infection. The seed recruitment and seedling growth data were provided by seed-addition...
Effect of pathogens on clonal plants
Koděra, Ondřej ; Koubek, Tomáš (advisor) ; Duchoslavová, Jana (referee)
1 Abstract: More than half of Central Europe's plant species are capable of propagating vegetatively via clonal growth, many of them identifiable as some of the most common species. Clonal ecology has been studied mainly due to its positive influence on plant fitness; Less attention, however, has been dedicated to the cost of clonal growth which is directly connected to the pathogen's inner plant invasion and transmission. The existence of clonal growth enables both partners in the plant-pathogen interaction to create new life strategies differing from those created by infected nonclonal plants. Pathogens that infect plants with a strong lateral spread were selected for higher aggressivity in evolution. In turn, their effect is negative on survival, the creation of new ramets and also on the whole growth and development of the host. If the development of the clonal growth organs becomes faster than the growth of fungal hyphae, the ramets can escape the infection passively. The influence on the host is not only negative as the infected plant can perform stimulated clonal growth or compete with healthy plants to a more successful extent. The aims of this thesis are: to search and summarize all the available information concerning this specific plant-pathogen interaction; to discuss the unanswered questions...
Invasions of phytophagous insects in Central Europe
Rejmanová, Aneta ; Špryňar, Pavel (advisor) ; Koubek, Tomáš (referee)
This Bachelor thesis is meant as a literature search concerned with invasions of phytophagous insects in Central Europe (mainly in the Czech Republic). I have summarized the findings from Czech and foreign studies dealing with this issue. Biological invasions are now a significant phenomenon. About 400 species of non-native insects occur in the Czech Republic, of which about half are phytophagous insects. In my Bachelor thesis I dealt with terminology that related to this subjekt, some more general regularities in the relationship of plants and insects, the primary areas of non-native insects, their pathways and their impact. I also chose few well-known representatives for better ilustration and I trying to find out, which plants non-native insect attacks the most. Key words: alien insects, phytophagous, plant, invasive
Ecology of flower smuts (Microbotryum) and their hosts from family Caryophyllaceae
Koupilová, Klára ; Koubek, Tomáš (advisor) ; Marková, Jaroslava (referee)
Anther-smut fungus (Microbotryum spp.) infecting plants of the Caryophyllaceae represents one of the most extensively studied plant pathogen systems. Anther-smut is a pollinator-borne disease that turns infected plants completely sterile. The aim of this thesis is to sum up the main findings about ecology and epidemiology of anther-smut disease and it mainly deals with various factors that influence disease spread and occurrence in nature. According to existing research, abiotic factors play minor role compared to biotic factors and interactions. Among the most pronounced, we can find variability in pathogen virulence and host resistance and also vector behaviour. When studying epidemiology of Microbotryum spp., it is necessary to take account of spatial population structure and metapopulation dynamics as well. Comparing life histories of different host species can also bring useful information. Key words: anther-smut, Microbotryum, Caryophyllaceae, pollinators, resistance, epidemiology, metapopulation dynamics.
Habitat dependence of persistence of clonal connection in plants
Martincová, Nina ; Weiser, Martin (advisor) ; Koubek, Tomáš (referee)
The review is about the role of environment to the longevity of connection in clonal plants. The first part is dealing with theoretical models, which describe the interaction of plants with different strategies in longevity of clonal connection in a model habitat. Subsequently, it analyses concrete attributes of the environment - heterogeneity, carrying capacity, amount of disturbances and competition. This part focuses more thoroughly on their impact on persistence of clonal connection and strategy of clonal reproduction in general. The last part refers to some other phenomena which could influence the length of persistence of a clonal connection.
Ecology of the pathosystem Vinca minor - Puccinia cribrata in natural populations
Vaníček, Jiří ; Koubek, Tomáš (advisor) ; Macek, Martin (referee)
5 Absctract Environment and demographic characteristics of host population are important factors affecting incidence and severity of plant diseases. The aim of this study was to reveal possible effects of microclimatic and edaphic characteristics and host population demographic factors on the biotrophic pathogen Puccinia cribrata, microcyclic rust parasitising clonal evergreen plant Vinca minor. I studied the ecology of this pathosystem in natural populations of V. minor in the Soča valley in the Julian Alps in Slovenia. Rugged terrain of the Soča valley with different bedrocks allowed to study pathogen distribution at topographically diverse forest and scrub sites, greatly differing in soil depth and canopy structure. P. cribrata was significantly more likely to occur in the themophilous forest with shallow calcareous soils and open canopy than in the mesophilous forest types. Its prevalence (proportion of diseased stems in population) was also highest in this type of vegetation. Most important host population factors were population size and population density positively affecting incidence and prevalence respectively. Additionally, I tested various vegetation and topographic indexes derived from remote sensing for usability in prediction models. It appears that vegetation indexes connected with canopy...

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