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Allelopathy in constitution of plant communities
Kučera, Pavel ; Weiser, Martin (advisor) ; Hadincová, Věroslava (referee)
Allelopathy, the ability of some plants to decrease the fitness of other plants by secondary metabolites, has been known for a very long time. The scientific community paid great attention to its research. Despite this, there is still a lot of ambiguity surrounding this phenomenon. In the past, the role of allelopathy in the constitution of plant communities had been often overlooked. The situation improved slightly in the past years. Several new articles summarizing information about the ecological aspect of allelopathy have been published. However, there are many unanswered questions about its widespread in plant communities and the degree of its influence on the ecosystem. This bachelor thesis is focused on summarizing contemporary knowledge about the influence of allelopathy, mainly from the ecological viewpoint, and presenting possible directions for future research. There is included a short list of the most common allelochemicals, basic principles of the functioning of allelopathy, its widespread through plant taxa, and its effect on the plant communities, mutualistic microorganisms, and the whole ecosystem. There is also mentioned the role of allelopathy in the process of invasion of alien species and at the end of the thesis, I discussed possible utilization of accumulated information in...
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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.
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Plant interactions in environments with fluctuating nutrient levels
Gawliková, Karolina ; Weiser, Martin (advisor) ; Hanzelková, Věra (referee)
Plants are affected by heterogeneity of nutrients in their environment but also by the plant competition for nutrients. In this study I review limits of contemporary studies and suggest possible alternatives. Currently, there is no experimental way to separate the effect of neighbour and the effect of fluctuating nutrients. For better understanding of plant interactions in environments with fluctuating nutrient levels, it is crucial to have thorough understanding of the heterogeneity itself, of the reactions of plants on said heterogeneity and also of the plant competition for nutrients. Then it is important to incorporate all this information into planning of the experimental design and simultaneously have them in mind when interpreting the acquired results.
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Natural regeneration of spruce stands in Vysoké Tatry (High Tatras) after large scale disturbation
Michalová, Zuzana ; Weiser, Martin (advisor) ; Wild, Jan (referee)
The observational study on natural regeneration of Norway spruce (Picea abies) was provided during seasons 2010 and 2011 in the windthrow area of High Tatra National Park. The main aim of this master thesis was to describe the distribution pattern in Norway spruce regeneration as well as to estimate the spatial scale, which most preciselly describes the differences in its phenotypic variability. Following step was to determine the relative influence of abiotic and stand factors on the growth characteristics and abundance of spruce seedlings. The Main focus lied on stressing the role of biotic interactions, like intraspecific and interspecific competition, leading to certain discrepancies in the phenotype, as well as in abundance of spruce seedlings.The reponse in variability in spruce traits was recognized at each spatial level. The results showed clear causality between soil moisture and vegetation composition, which both directly modified not only the phenotype of spruce seedlings and plants, but have even influenced their counts on particular stands.
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Competition of seeds and seedlings and its influence on the timing of germination
Kos, Pavel ; Weiser, Martin (advisor) ; Vazačová, Kristýna (referee)
Competition of seeds and seedlings is being reviewed in this bachelor thesis, namely relationship between competition with different timing of germination and different seed mass. The question is when and why timing of germination is changed. There is a lot of factors creating very big variation in results. Main factor is presence of other plants in same site. Also a lot of abiotic factors take very importatnt part. Because of this variability we can not pronounce clear answer. Key words: germination, competition, seed mass, timing of germination, seed, seedling
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What is the role of secondary metabolites in ecology of Asteraceae species?
Koutská, Barbora ; Weiser, Martin (advisor) ; Latzel, Vít (referee)
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)
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Integration of clonal plants in heterogeneous environment
Vinšová, Jana ; Weiser, Martin (advisor) ; Macek, Petr (referee)
Clonal plants may be able to cope with spatial and temporal heterogeneity due to the physiological integration of ramets. To begin with, I discuss basic characteristics of clonal plants and then I provide a review of theoretical and empirical work dealing with the advantages and disadvantages of clonal growth in heterogenous conditions. Three main traits - translocation of resources, division of labour and foraging - are examined in terms of their contribution to the success of clonal plants. Despite a large amount of attention which this topic has received in the past few decades, a number of issues still remain unclear.
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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.
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