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Vliv nízké teploty na propustnost buněčných membrán a přežití rostlin
Kubovčíková, Anna
Plants are naturally exposed to low temperatures in nature. During the winter, the temperatures are the lowest and in certain places they even reach very low values. Jasmonic acid plays an important role in the plant's resistance to low temperatures. In the thesis, we have focused on the effect of the PLIP genes that produce precursors of jasmonic acid. The role of the genes in cold resistance in Arabidopsis thaliana was studied after acclimation in different light conditions. The observed parameters in plants acclimated to low temperatures were the parameters of photosynthesis, intactness of cell membranes and survival after exposure to freezing. The results of the experiments proved that the mutation of the PLIP genes cause a decrease in the integrity of the cell membranes when exposed to freezing, and conversely, the ectopically increased expression of the PLIP3 gene results in an increase in plant resistance. Based on ion leakage, we determined LT50 values for each variant, and it was shown that the difference between the most resistant transgenic line plip3 ox and the mutant line in all three PLIP genes is more than 4 °C. Subsequently, a plant survival test after freezing was performed, where it was demonstrated that the LT50 value correlated with plant survival. Chlorophyll fluorescence analysis showed that after acclimation to low temperature, there are no large differences in photosynthetic parameters between individual genotypes with modified PLIP level. The light that was applicated during acclimation had a more pronounced effect on the plants. Plants acclimated at low intensity showed higher values of non-photochemical quenching as well as greater maximum quantum yield of photosystem II. The results prove that the PLIP genes are significantly involved in the resistance of plants to low temperatures.
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Vliv světla na fotosyntézu bylin v podrostu doubrav
Zvyniatskovskyi, Yan
The forest environment is increasingly changing. Climate change brings along not only changed macroclimate. Stand microclimate is changing as well due to changes in tree species composition and the natural reduction in tree cover because of increased mortality. Understory herbs are sensitive to changes in the tree canopy cover. In sparse stands, more light reaches the understory compared to dense stands. Different understory herb species have different ability to use light and adapt to changing conditions. Short-term changes in their photosynthesis lead to long-term changes in species composition and their abundance. This bachelor thesis investigated the effect of different light availability on the photosynthetic parameters of understory herbs. I compared 8 taxa from four groups of Ellenberg ecological indicator values (EIV). The research was carried out in a stand of thermophilous oak-hornbeam in the Pálava Protected Landscape Area (PLA), on plots with different levels of tree canopy thinning. Herbs growing under fully stemmed stands plastically reduced respiration compared to herbs in the thinned forest, which allowed them to survive even under dense forest cover. However, they were still able to achieve high rates of photosynthesis under full illumination for short periods of time, i.e., they actively utilized short episodes of direct sunlight. Species characterized by EIH as shade-loving respired less in the dark than species with higher EIH in relation to light, suggesting a link between light availability and long-term abundance of herbaceous taxa. The results of this study suggest how the herbaceous understory of temperate forests might change in the context of climate change, with potential implications for forest typology.
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Teaching the Topic of Photosynthesis using Aspects of Inquiry-based Learning
Rapantová, Lenka ; Vojíř, Karel (advisor) ; Nejedlý, Adam (referee)
This bachelor thesis deals with the teaching of photosynthesis in primary school science classes. The aim of the thesis was to validate a teaching program with elements of inquiry- oriented teaching, to find out its effectiveness on the level of knowledge acquired by the pupils of the seventh year at the second grade of the primary school. To investigate the educational effect, an initial pre-test was designed to ascertain the pupils' prior knowledge. Furthermore, the knowledge acquired after the laboratory tasks were carried out was analyzed and verified by an analogous post-test. The premise was that the laboratory activity would motivate the pupils' interest in science and provide a better understanding of photosynthesis, especially its inputs, waste substances and products. Another aim of this thesis was to find out how pupils perceive the attractiveness, value and usefulness of the tutorial after completing it and how they evaluate their efforts in this type of learning. A standardized IMI (Intrinsic Motivation Inventory) questionnaire survey was used to determine the above. The paper describes in detail the different laboratory tasks that were part of the curriculum applied in science classes, as well as the procedures necessary for their implementation and the students' reactions to the...
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A probe of student´s knowledge of photosynthesis at the lower-secondary school
BOHÁČOVÁ, Nikola
This bachelor's thesis focuses on pupil's knowledge about photosynthesis and the other related processes in the terrestrial plants. The aim of the thesis was to find out misconceptions of the ninth grade pupils of elementary schools and lower grammar schools. It also deals with attitudes of teachers about teaching photosynthesis. Theoretical part of this thesis mentions physiological processes of plants and their possible misconceptions. These misconceptions are common in Czech and foreign studies. The study was realized in four elementary schools and lower grammar school using a questionnaire survey. The results of the survey declare that there are misconceptions and insufficient knowledge of plant physiology. Answers from biology teachers state that teaching biochemical processes in lower grades of primary school is difficult.
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Teaching photosynthesis using digital technologies
MUSILOVÁ, Zuzana
The aim of this thesis was to determine whether the use of the proposed interactive digital textbook leads to an improvement in students' understanding of the topic of photosynthesis in terrestrial plants. The effect of teaching with this textbook on the attractiveness of science learning and the removal of pupil misconceptions was also investigated. The research was conducted by pretest and posttest system. From the statistically evaluated data obtained, it can be concluded that the digital textbook has a positive effect on students' understanding of the topic of photosynthesis.
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Experimental tasks for teaching photosynthesis of aquatic plants at the elementary school
VAITH, Miroslav
This bachelor's thesis deals with the influence of experimental tasks using a measuring device on the knowledge of pupils in the field of photosynthesis (especially the photosynthesis of aquatic plants) and the refutation of misconceptions related to this topic. In addition to knowledge, the attractiveness of this type of teaching for pupils was also investigated. The knowledge and attractiveness research was conducted in the form of a pretest and posttest. The thesis confirms the positive effect of experimental tasks on the knowledge and attractiveness of the topic of photosynthesis among pupils in elementary school.
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Vliv modifikace receptoru ultrafialového světla na jeho funkci
Blechová, Veronika
Ultraviolet radiation has a negative effect on living organisms, but it is also signal modulating growth and development in plants. This thesis is focused on the effects of UV-B light in Arabidopsis thaliana mutants in UV-signalling pathway with modulated cytokinin level. Our data show that UV-B decrease the quantum yield of the PS II (Fv/Fm) in both mutant lines. Decrease of Fv/Fm was accompanied by growth retardation which could be reverted by exogenous application of 1 µM BAP. Determination of the pigments showed that cytokinins interact with UV-B light and this interaction is dependent on the functional UVR8. On the other hand, inhibition of the thermomorphogenesis by cytokinins is independent of the functional UVR8. Experimental work was also focused on the creation of the fusion genes containing modified UVR8 sequence with marker gene eGFP. The correct sequence of the recombinant GFP was confirmed by commercial sequencing.
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Reakce sazenic břízy bělokoré (Betula pendula Roth.) na stres suchem
Orlovský, Vít
Climate change, with its accelerating intensity, is the primary factor to which forest and urban stands need to respond. Particularly more frequently, recurrent periods of drought, coupled with rising average annual temperatures, mainly in urban development, represent a significant plant stressor. As silver birch (Betula Pendula Roth) is a frequently used tree in urban plantings, the aim of this work was to assess the physiological response of silver birch seedlings after the completed leaf development to stress by drought. Evaluation of the response of the seedlings to stress confirmed the assumption that water potential decreases as the drought increases. Due to the stress of the drought, we saw an 86% decrease in water potential measured at noon compared to the beginning of the experiment. From the results of a 17-day experiment, we found that stress from drought caused a 96% decrease in the rate of photosynthesis and stomatal conductance. So birch seedlings reacted very sensitively to drought stress by trying to avoid reducing water potential. When comparing the variability of the responses of individual seedlings, the physiological parameters showed a marked difference in their response to stress by drought. For example, for rate of photosynthesis, the coefficient of variation for stressed seedlings reached 97% at the end of the experiment. The PRI reflectance index, which indirectly characterises the carotenoid content, showed a coefficient of variation of even 306%. All this information provides us with clear evidence of the ability of individual birch seedlings to react to drought stress in a different way. Based on our measurements and subsequent results, we can conclude that the variability of silver birch seed material is able to respond to the demands implied by the projected climate change.
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