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Physiological responses of plants to arficial light
Holečková, Barbora ; Münzbergová, Zuzana (advisor) ; Konrádová, Hana (referee)
The topic of this bachelor`s thesis is the physiological response od plants to artificial lighting, meaning artificial lighting from street lamps, which is one of the important anthropogenic influences. Artificial lighting at night is referred to by the acronym ALAN (from the english phrase Artificial light at night) and can have a significant effect on plant behaviour. In this thesis, the current knowledge on the influence of streetlights on not only plant behaviour but also on entire ecosystems is summarised in the theoretical part. In the practical part, the chlorophyll content of plants is measured, which is an important parameter informing about their physiological state, i.e. whether nighttime artificial lighting has an influence on it. Subsequently, the detected chlorophyll content of plants under street lighting is compared with that of paired control plants in their surroundings that are not under any artificial lighting. The measurements are carried out using a specially designed instrument for the detection of chlorophyll content in plant leaves called CCM300. The result of the work is the understanding of the possible effect of street lighting Key words Physiological reaction, artificial light at night, plants, chlorophyll
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Variability in the response of exodermis to nutrient deficiencies in the environment
Klvaňová, Renáta ; Tylová, Edita (advisor) ; Konrádová, Hana (referee)
v angličtině Plant growth and development is largely dependent on the soil environment which is a source of minerals and water needed for plants to survive. However, the availability of these resources in the soil is very heterogenous and important elements can be leached into the lower parts of the soil or bound to soil particles. Plants have therefore developed a number of adaptations during evolution to increase the efficiency of the root system. One of these aspects are the apoplastic barriers (endodermis and exodermis). Both of these layers affect the transport of substances to and from the root, thereby limiting unregulated apoplastic transport through modifications of the cell walls where the polymers that limit the transport of substances are deposited. These are Casparian bands and suberin lamellae. They often differentiate more rapidly when plants are faced with a stress factor such as drought, salinity or toxicity. However, nutrient deficiencies (e.g. N, P, K and Fe) also affect the rate of differentation. Deficiencies can result in both acceleration and deceleration of differentation, which seems to help optimize root transport properties according to the current conditions. However, this reaction has been less studied so far. This work therefore focuses on the analysis of the response...
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Phototropic memory in early plant development
Šišková, Michaela ; Konrádová, Hana (advisor) ; Krtková, Jana (referee)
This thesis was inspired by controversial published results on the existence and reliability of a memory trace of the direction of the last illumination in young dicots. The theoretical part first covers phototropism, it briefly summarizes current knowledge about this growth movement, phototropins, and the mechanism of phototropic bending, including the role of auxin and its transporters. It also discusses the effect of previous light exposure on hypocotyl bending. Another section of the theoretical part is focused on the question of the existence of memory in plants. The experiments performed in the practical part are based on the assumption that plants are able to store a memory trace of previous light exposure. After the establishment of a system that made it possible to obtain a robust phototropic response to blue light, seedlings of the model plant Lepidium sativum were tested under different conditions to see if and how the direction of light affected the plants' response to subsequent phototropic stimulation. The results suggest that in at least one case, the final phototropic response could be interpreted as a formation of a specific memory trace in the tested plants. However, based on the results of this work, the existence of a memory trace of previous light exposure cannot be...
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Plant growth on saline soils - interaction of sodium and potassium in plant metabolism
Peřinová, Anna ; Tylová, Edita (advisor) ; Konrádová, Hana (referee)
Soil salinity represents a significant stress factor that negatively affects plant growth and is also a current problem in modern agriculture. This bachelor's thesis focuses on the mechanisms associated with this stress, with a main emphasis on the effects of excess sodium cations in the soil, their accumulation in plants, the mechanism of their negative impact, and defense strategies. It addresses the importance of potassium and sodium in plant nutrition and metabolism, as the interference of Na+ with the essential functions of K+ is an important aspect of the stress caused by salt excess in the environment. The thesis analyzes the most important transporters and channels that ensure the uptake and transport of K+ and Na+ in plants. Emphasis is placed mainly on the transport of sodium and the mechanisms that enable plants to adapt to saline environments and tolerate higher concentrations of salts in the soil, particularly the SOS defense system against Na+ accumulation in the cytoplasm and unique structures that allow salt secretion in halophytic plants. Attention is also directed to the difference between glycophytic and halophytic plants.
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Autumn leaf senescence in temperate and boreal woody species under changing climate
Kosová, Barbora ; Lhotáková, Zuzana (advisor) ; Konrádová, Hana (referee)
Autumn senescence of the foliage of deciduous trees of temperate and boreal zones is an annually recurring phenological phenomenon, which is part of the adaptation to life in the temperate and boreal zones with periods of frost and restriction of solar radiation. During foliar senescence, photosynthetic pigments decompose, mineral nutrients are remobilized and foliage falls off. The timing of foliage senescence in boreal and temperate deciduous trees is controlled by external and internal factors. The biggest role in the timing of senescence is played by photoperiod and temperature, which gradually decrease by he end of the growing season. The temperature is increasing due to global warming, thus affecting the length of the growing season and the sequestration of carbon into forest stands. Other factors (such as water availability) are also affected by climate change. The above-mentioned factors affect the trees of boreal and temperate forests to varying degrees, and it is, therefore, important to address them in order to be able to estimate the future development of foliage senescence and carbon sequestration in temperate and boreal forests.
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Effect of artificial light at night on ecophysiological functions of plants
Ležal, Lukáš ; Konrádová, Hana (advisor) ; Lhotáková, Zuzana (referee)
Artificial light at night, as a significant source of anthropogenic pollution, has long been overlooked, both among the general public and in the scientific community as well as at the legislature level. Steps to reduce the negative impacts of artificial light at night have been taken late and to an insufficient extent, and it was the low general awareness that was one of the motivations for the bachelor thesis on this topic. Plants are a group of organisms that receive less attention than, for example, humans, although they far exceed them in ecological importance. Artificial light at night has the potential to alter the composition of plant communities and the food webs that are linked to them, of which humans are at the top. This is done by shifting plant phenological phases, disrupting the natural perception of day and night, modifying growth patterns and morphological characteristics, increasing irradiance stress or reducing the efficiency of photosynthesis. It is through a comprehensive knowledge of the interaction of plants with artificial light at night that society can effectively protect nature and introduce the necessary new standards and technologies to ensure sustainable development.
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Physiological basis of the tradeoff between growth and defense against abiotic stress: the role of carbon balance
Doložílek, Jakub ; Konrádová, Hana (advisor) ; Petrášek, Jan (referee)
Similarly to other organisms, plants must coordinate growth and development with their energetic status. Besides that, considering their sessile way of life, they need to adapt very precisely to the environmental conditions of their habitats. However, from the point of view of invested resources, the defence mechanisms may be very expensive, and so, their activation is usually accompanied by a restriction of growth. Hence, establishing functional dynamic balance between investment to growth and defensive reactions ("G-D tradeoff") is essential for the plants fitness, competitiveness and reproduction success. The thesis examines the mechanisms that are fundamentally contributing to this balancing. In this work, evolutionarily conserved axis coordinating growth and development with energetic status consisting of TOR kinase, positive growth regulator during favourable conditions, and her antagonist, the SnRK kinase, inducer of resources mobilization in purpose of realizing defensive measures securing energetic homeostasis, is discussed. Further, this thesis focuses on plant-specific pathway which links the TOR-SnRK1 axis with perception of environmental conditions. The main components of this pathway are the SnRK2 kinases, coordinators of specific defensive reactions, PP2C phosphatases and...
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Heat-shock proteins and plant tolerance against high temperature stress
Ott, Kristián ; Hála, Michal (advisor) ; Konrádová, Hana (referee)
In context with ongoing climate change, the average temperature is still rising. This is a problem mainly for agriculture and production of groceries, because plants generally have difficulties when coping with ambient temperature higher than 40 řC. If there would be continuing trend in decrease of global food production, it could cause problems with feeding still growing world population. Organisms in general developed many mechanisms of stress adaptation. One of these evolutionary adaptions to high temperature stress is production of heat shock proteins (HSPs). HSPs are very conserved family of proteins present in both prokaryotes and eukaryotes. This thesis summarizes present knowledge about the HSPs and their function (not only) during the high temperature stress in plants, but some of the information presented in this thesis were obtained also from other organisms. The thesis starts with general introduction to the high temperature stress and how plants can sense the ambient temperature. Next is general mechanism of induction of HSPs and their classification, structure, and mechanism of action. The possibility of future use of HSPs in agriculture and medicine is opened in last chapter.
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Adaptation of Plantago plants to environmental conditions: the role of carbohydrate balance
Skulníková, Barbora ; Konrádová, Hana (advisor) ; Lhotáková, Zuzana (referee)
Sorbitol is a linear sugar alcohol which is, together with sucrose, the primary photosynthetic product in the Plantaginaceae family. Sorbitol and sucrose are used for long-distance transport of photosynthetically fixed carbon via phloem. Many plant species accumulate sugar alcohols during drought or salt stresses, and it leads to higher tolerance to these stress conditions. The aim of this diploma thesis is to describe selected metabolic and structure differences with a focus on the sorbitol and sucrose balance, in two Plantago species - glycophytic Plantago lanceolata and halophytic Plantago maritima, which differ in life strategies. The plants were cultivated hydroponically in Araponics boxes. Previous results of our team show, that sorbitol accumulates in Plantago leaves up to ten-times higher concentrations compared with sucrose. This difference is deepened when the plants are exposed to salt stress. Sorbitol to sucrose ratios vary between vascular tissue and phloem sap. We assume that increased salt tolerance of P. maritima is based on the different distribution of assimilates through the plant, and by their partitioning between metabolic, storage and transport pools in mature leaf, which also manifests under non-stress conditions. In both genotypes, I compared growth rates under standard...
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