National Repository of Grey Literature 72 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Physiological, structural, and biochemical leaf traits of selected Poaceae species involved in oxidative stress protection and acclimation to different light conditions
Hunt, Lena Macrie ; Albrechtová, Jana (advisor) ; Lux, Alexander (referee) ; Šantrůček, Jiří (referee)
This thesis examines physiological, structural, and biochemical leaf traits in grasses (Poaceae family) and how they contribute to oxidative stress protection. Light is a major factor contributing both to oxidative stress in plants and the induction of protective mechanisms at the leaf level. The agriculturally important species barley (Hordeum vulgare) was used to investigate responses to varying irradiance and atmospheric CO2 levels. Barley was further used as a model organism to study the influence of different spectral qualities on oxidative protective mechanisms, particularly phenolic compound induction. This thesis also examines the protective leaf functional traits of wild grass species (Nardus stricta, Calamagrostis villosa, Molinia caerulea, and Deschampsia cespitosa) in a high-irradiance arctic-alpine tundra grassland. Phenolic compounds are important protective secondary metabolites in plants that protect against oxidative stress from high irradiance. This thesis evaluates phenolic compounds and their contributions to plant stress tolerance and introduces a novel method of quantifying the histochemical detection of phenolics in leaf cross-sections. Key results indicate that light quantity and quality play major influential roles in the accumulation of phenolic compounds. High irradiance...
How will a longer vegetative season affect carbon sequestration in plant biomass
Kasperová, Denisa ; Albrechtová, Jana (advisor) ; Ponert, Jan (referee)
As a result of human activity, a large number of greenhouse gases, especially CO2, is released into the atmosphere, which causes a greater greenhouse effect and an increase in the temperature of the surface of the planet and the air in the atmosphere. Ongoing climate change is one of the great challenges facing society, as rising temperatures on the planet greatly affect the functioning of its ecosystems. Extremes arising from climate change, especially temperature rise and lack of precipitation or a change in the annual distribution of precipitation, affect the physiology and phenology of plants. Higher temperatures cause plant growing seasons to shift and lengthen, which has a direct impact on the sequestration of carbon in plant biomass through a biochemical, physiological plant process called photosynthesis. The increase in CO2 concentration in the atmosphere is slowed down by terrestrial forest ecosystems, as they can retain carbon in their tissues, especially in wood, for a relatively long time before it returns to the atmosphere. However, the efficiency of binding carbon into biomass also depends on other physiological processes, e.g., photorespiration, breathing, gas exchange between the plant and the atmosphere. Stressors caused by climate change can then limit growth, photosynthesis,...
The importance of root exudates for crop cultivation under climate change
Schnürer, Oliver ; Albrechtová, Jana (advisor) ; Tylová, Edita (referee)
Root exudates are compounds secreted by plant roots that can help plants, for example, to obtain nutrients from the soil or to increase their resistance to biotic stress. Root exudates can thus hide a great potential that can be used in agriculture. As human population grows, there is increasing pressure on agriculture, which must provide enough food to feed the global population, thus ensuring food security. Until now, agricultural activity has tried to satisfy this demand by intensification of agriculture, mainly by breeding highly productive crops when using intensive fertilizing, but the theoretical possible benefits of root exudates in breeding remained overlooked. Intensive farming practices can further exacerbate the impacts of ongoing climate change, for example by increasing soil carbon mineralization or reducing biodiversity. By using root exudates in the production of crops, it will be possible to achieve a higher nutrient content in soil, as well as a higher resistance of crops to pests, without the aforementioned negative impacts of intensive agriculture. In this work, I tried to describe the main functions of root exudates, their reaction to increased CO2 concentration in the atmosphere, their stress response caused by stressors of climate change and their theoretical use in...
Reproductive isolation barriers in the hybrid zone of the house mouse (Mus musculus)
Albrechtová, Jana ; Piálek, Jaroslav (advisor) ; Sedláček, František (referee) ; Reifová, Radka (referee)
Reproductive isolation occurring at the gamete level is called gametic isolation and almost always prevents gene flow between unrelated species and (to some extent) between closely related species or subspecies. The hybrid zone of the house mouse (HMHZ), which was formed by contact and interbreeding of two subspecies, the Western European house mouse (M. m. domesticus) and the Eastern European house mouse (M. m. musculus) provides a usefull model for the study of speciation processes involving gametic isolation. The probability of sperm competition within the female reproductive tract is high in the house mouse because high levels of sexual promiscuity (in 20˗40 % of all reproductive cycles) have been observed in this species. Thus, the reproductive isolation at gametic level may be determined both by the phenotypic characteristics of sperm (the ability to outcompete heterospecific sperm in the process of sperm- sperm competition) and by the preference of the sperm of conspecific males in the female reproductive tract (cryptic female choice). In my Ph.D. thesis I tested the degree of affinity of male and female gametes reciprocally between the both subspecies of M. musculus and the phylogenetically more distant species M. spretus, which is characterized by a higher degree of promiscuity. Although a...
Evaluation of the physiological status of European beech in its plantings on localities following the gradient of its ecological valence
Palouš, Daniel ; Albrechtová, Jana (advisor) ; Tomášková, Ivana (referee)
European beech (Fagus sylvatica L.) is one of the dominant tree species in Europe, presenting a keystone species for forest ecosystem functioning. The ongoing climate change alters the environmental conditions in the areas of the current distribution of European beech, leading to stress. Concerning the critical health status of forests in the Czech Republic and other European countries, it's even more urgent to monitor the health status of forests. For this, tools for early detection of a stand's physiological status decline are needed. The aforementioned tools can consist of indicators of the physiological status suggested by this thesis. This thesis aims to evaluate the applicability and sensitivity of the preselected set of indicators of the physiological status of European beech to the gradient of environmental conditions (temperature, precipitation) within its ecological valence. Four stands of European beech presenting the gradient of beech's ecological valence were observed over the peak of one vegetation season. Stand Kocanda presented the microclimatic and ecological optimum; stand Hradecko was on the lower margin of the altitudinal gradient of European beech distribution and presented the limit of low water availability; stand Deštné was on the upper margin of the altitudinal gradient of...
Detection of bark beetle attack of Norway spruce using spectral and biophysical data at different hierarchical levels
Vesecká, Martina ; Albrechtová, Jana (advisor) ; Tomášková, Ivana (referee)
There was created an overview of key aspects for a correct understanding of the dynamics between bark beetle and Norway spruce, especially the way of life of the beetle and the time course of its life cycles. It is absolutely essential to understand this interaction for a timely and effective solution to the bark beetle calamity. Furthermore, the mutual interaction of beetle and tree is discussed in detail in the text. Great emphasis is placed on the description of the spruce's defense mechanisms and the consequences of the attack. In particular, biophysical changes in the needles, which cause a change in the spectral behaviour of the leaves and thus the entire forest stand. Using sensor capable of measuring the reflectance of surfaces, it is possible to detect a bark beetle-infested tree much earlier than changes in the needles could be detected by the naked eye and remove it while it is still colonized by the beetle and not spreading further into surrounding trees. This is key to managing not only the current bark beetle calamity. An overview of case studies is given in the thesis, where the use of spectral methods at different hierarchical levels was applied and satisfactory accuracy in the identification of early infested trees was achieved. Key words: Norway spruce, bark beetle, bark beetle...
Changes in the contents of anthocyanins and photosynthetic pigments in barley leaves under the effect od climate change factors
Nikodymová, Michaela ; Albrechtová, Jana (advisor) ; Mašková, Petra (referee)
Ongoing climate change and its manifestations have a significant impact on agricultural crops, which are exposed to a wide range of abiotic (drought, high or low temperature, elevated UV radiation) and biotic (pathogens, pests) stress factors that can dangerously affect their growth and yield. One of the very important phenomena of climate change is the increasing concentration of CO2 and other greenhouse gases in the atmosphere. Manifestations of climate change, such as high temperature and drought, interact together with increased CO2 concentration, and these interactions can have serious effects on vegetation. This diploma thesis examines the effect of climate change factors and stress factors on the content of pigments with the importance of plant protection against stress, namely photosynthetic pigments and anthocyanins in barley leaves. The aim of the thesis is to find out whether and what are the differences in the response to these factors in two varieties of barley, differ in their resistance to photooxidative stress. The plants were grown in pots in growth chambers under controlled conditions and in flower beds in adjustable greenhouses with open roofs in the experimental station of plant ecophysiology Domanínek of the Global Change Research Institute of the Czech Academy of Sciences in...
The effect of temperature on plant growth: teaching protocols of model experiments
Máhrlová, Zuzana ; Albrechtová, Jana (advisor) ; Mourek, Jan (referee)
This diploma thesis is focused on the creation of model tasks (by means of an experiment) for the study of biology at secondary schools and concerns the effects of temperature on plant growth. The selected tasks utilize the new didactic approach by means of the so called inquiry based education. This method of teaching contributes to the development of individual deduction reasoning and encourages the students to actively think about the subject matter. The thesis provides the necessary theoretical background for the topic together with the description of methods and material needed for the conducting the experiments. Furthermore, the thesis describes the necessary instructions and procedures to conduct the experiment and its use in the secondary school teaching practice and presents the requisite methodical guidelines and worksheets for them. Simultaneously, the thesis verifies the didactic applicability of the experiment and the worked out materials through a questionnaire survey and monitored application of the model tasks at secondary schools. The main result of this diploma thesis is a modern, functional and verified method of teaching for high school about the effects of temperature on plant growth in accordance with modern approaches to education, which include own experiments, their...

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