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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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Allelopathy of aquatic plants and its possible application to control cyanobacterial blooms
Kolářová, Anna ; Jandová, Kateřina (advisor) ; Kučerová, Andrea (referee)
The excessive growth of phytoplankton and the development of water bloom leading to the damage to aquatic ecosystems are becoming a more and more frequent problem. There are many methods to control the water bloom from which mainly those that use interactions of living organisms have been developing lately, with the utilisation of aquatic plant allelopathy being one of them. Allelopathy is a type of relationship between two organisms when one of them influences the other by secreting allelopathically active compounds in the environment. However, the effect of these secondary metabolites depends on many biotic and abiotic factors, which also has consequences for their potential use to control the water bloom. Although the results of many studies suggest that allelopathy can affect the community of phytoplankton, its role in aquatic ecosystems is still unclear. This thesis summarizes the knowledge about the occurrence of allelopathy among aquatic organisms, the modes of action of allelochemicals and the impacts of the key factors influencing the allelopathic effect. At the same time, it evaluates the prospects of using the allelopathy of aquatic plants to control water bloom and reviews experimental approaches to studying allelopathic interactions.
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Study of Allelopathic Effects of Common Millet on Other Plants
NWAJEI, Lucky
Proso millet (Panicum miliaceum) is an important source of energy and protein for people and as well animals. At present, there are practically no data available on the allelopathic effect of proso millet. The aim of the work was to evaluate the alle-lopathic effects of common millet on selected crops and to suggest the possibility of using the acquired knowledge. Laboratory experiments included evaluation of the effect of extracts from plant parts of millet and millet seeds on seed germina-tion and growth of selected plant species, as well as evaluation of autotoxicity of millet extracts, evaluation of the effect of different densities of millet seeds on allelopathic activity and stability of millet allelochemicals. The most effective extract inhibiting the growth of selected plants was the extract from young millet plants. However, millet allelochemicals do not seem to be suitable for weed control due to their low stability.
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Možnosti využití travních porostů v rámci agrolesnictví
Macek, Libor
The bachelor's thesis deals with the use of grasslands with a focus on grasses and clover in agroforestry systems. The first part describes the agroforestry itself – its characteristics and significance. Furthermore, emphasis is placed on woody plants suitable for agroforestry systems, especially in the conditions of Central Europ, as well as on their production and non-production functions. The most suitable representatives are for example, walnut (Juglans), poplar (Populus), but also less economically used representatives, such as cherry (Prunus) or rowan (Sorbus). At the same time, agroforestry is divided into certain units, which are characterized by their functions, both in the tropics and in Europe. The most typical systems in Europe are mainly silvopastoral systems, but also increasingly used alley cropping on arable land. The second part describes various agroforestry systems using grasslands as well as practical examples of functioning systems in different climate zones. Attention is also paid to individual members of the family Poaceae and Fabaceae suitable for their characteristic properties in these systems. The most important for shading appear to be tolerant representatives such as Agrostis stolonifera L. or Festuca arundinacea Schreb. from the Poaceae family or Meadow clover (Trifolium pratense L.) from the Fabaceae family. Possible interactions related to the coexistence of woody plants, grasses and clover, such as competition and allelopathy, are also not neglected.
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Alleopathic potential of plants of Satureja genus
SLOVÁKOVÁ, Karolína
This work dealt with the study of the allelopathic potential of the winter savory (Satureja montana L.). The use of seeds, flowers, essential oil and aqueous extracts from shoots was used to determine the effect on germination, root and shoot length and dry weight of 8 selected plant species (white mustard - Sinapis alba L., lettuce - Lactuca sativa L., creeping clover - Trifolium repens L., ryegrass - Lolium multiflorum and 4 herbs of the family Lamiaceae: summer savory - Satureja hortensis L., thyme - Thymus vulgaris L., lemon balm - Melissa officinalis L. and sage - Salvia officinalis L.). At the same time, the inhibitions effects of savory plants on the occurrence of weeds in field conditions was monitored. From the point of view of the use of winter savory as a bioherbicide, the use of essential oil seems to be the most effective, followed by winter savory flowers and then aqueous extracts from savory shoots before flowering. The influence of the winter savory plants themselves before the involvement of the stand on the growth of weeds in field conditions was not proved.
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Alleopathic potential of plants of hemp (\kur{Cannabis sativa})
KLEJNA, Tomáš
The aim of the work was to compare the effects of germinating seeds, fresh flowers and aqueous extracts from fresh and dried parts (leaves and flowers) of hemp plants on seed germination of model crops - wheat, oats, white mustard, narrow-leaved lupin, white clover and lettuce in laboratory conditions. After 3 days of germination, the total length of the roots and shoots was measured. In individual variants, the relative allelopathic effect, average germination and statistical significance were evaluated. The effect of the distance of germinating seeds from samples of hemp material was also monitored. The effect of germinating hemp seeds, with the exception of oats, has not proved to be very significant. The effect of parts and aqueous extracts of hemp plants was as follows: -statistically significant inhibitory effect of the aqueous extract of the dried flower on the germination of wheat -statistically significant inhibitory effect of fresh flowers and extract from dried leaves of flowering plants on the germination of oats, there is also a statistically significant effect of the distance of germinating seeds from the sample of hemp material -statistically significant inhibitory effect of fresh flowers and extracts of fresh and dried leaves on the germination of white mustard, there is also an effect on average germination values -practically no or stimulating effect on the germination of legumes: narrow-leaved lupins and white clover -statistically significant inhibitory effect of fresh flowers and fresh leaf extract on lettuce germination, again with an effect on average germination
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Functions of secondary metabolites of lichens
Zvěřinová, Gabriela ; Svoboda, David (advisor) ; Bouda, František (referee)
This bachelor thesis is a review of available literature about lichen secondary metabolites and their functions. Lichens produce a great variety of these compounds; most of them are unique to the lichen symbiosis and are not found in higher plants. Besides the role of these compounds in chemotaxonomy and systematics, lichen secondary metabolites exhibit various biological functions and can affect biotic and abiotic interactions of lichens with their environment. Well-known and often described functions of lichen substances include especially antimicrobial, antiherbivory and antioxidant activity, allelopathy, metal homeostasis and photoprotection. This thesis is focused on these functions and summarizes current knowledge in this area. Key words: lichen, secondary metabolites, allelopathy, antimicrobial activity, herbivory, antioxidant activity, photoprotection, metal homeostasis, pollution tolerance, literary review
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Importance of root exudates in plant-soil interactions
Horčičková, Veronika ; Münzbergová, Zuzana (advisor) ; Janoušková, Martina (referee)
Plant roots are in constant contact with soil microorganisms and fungi, and they come in contact with soil fauna and the roots of other plants. All components of the soil biota communicate with each other. When it comes to plants it is often a chemical communication through root exudates, chemicals that plants release into the soil. Through root exudation, plants also affect the abiotic component of the soil, which helps them to obtain nutrients. The production of root exudates is important in attracting symbionts and beneficial organisms and, conversely, in repelling or killing pathogens and parasites. Thanks to root exudates, plants can recognize neighbouring plants, suppress the growth of competitors, or avoid competition with kin, and parasitic plants use root exudates as signals to find its host. By the action of root exudates, plants create their own community of microorganisms and fungi in the rhizosphere, adjust the availability of nutrients and thus actively change living conditions in the soil. This bachelor thesis focuses on plant interactions through root exudates and mentions the ways in which root exudation can be studied. The following diploma thesis will discuss the influence of root exudates of invasive plants on the native plant community.
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Study of germination and emergence of industial hemp seeds
ŘEZÁČOVÁ, Veronika
Nowadays hemp is listed among plants with a wide range of potentials. It can be used as a source of fibre, oil, food or medicine. The aim of this work was to investigate optimal conditions for hemp seed germination grown in laboratory as well as field conditions and to propose the application of acquired findings. Hemp seed was split into 2 size groups: above 3 mm and 2 - 3 mm. Divided seeds with the humidity level of 6, 9 and 12% were stored at the temperature of 0, 8 and 20? 1°C for half a year. In 2 months interval, there were evaluated: germination, energy of sprouting, speed of sprouting, further seed viability and laboratory emergence. From next influences were evaluated the influence of dryness, wetting, autotoxicity, exudates of perennial weeds, seed treatment with the infusion of field horsetail and the grown stimulator. The best germination and laboratory emergence had seeds stored at 0°C. Test of seed viability confirmed significant decline in live seeds stored over 4 months at the 0°C temperature. The best germination was achieved by seed size 2 - 3 mm. Hemp requires sufficient amount of water for germination. Leachates from rhizomes of couch grass inhibited germination of hemp by 10%. On the other hand, germination was significantly increased by the stimulator.
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