|
|
Soil application of hydrogels containing rhizobacteria
Hlaváčková, Barbora ; Černayová, Diana (referee) ; Kalina, Michal (advisor)
Plant growth-promoting rhizobacteria (PGPR) are a group of bacteria that can influence plant growth by their mechanisms. In recent years, there has been an increase in the use of these soil-supporting products in the form of biofertilizers to increase yields and improve crop growth in adverse conditions in an environmentally friendly way. The aim of this bachelor thesis was to assess the effect of the external addition of different application forms of PGPR on soil physico-chemical characteristics and on the growth of model plants of lactuca sativa without irrigation restriction in the first case and in the second case under irrigation restricted conditions. A particular strain of Azotobacter vinelandii CCM 289 was selected for the preparation of four forms of PGPR treatments, namely bacterial biomass suspended in PBS, alginate gel without bacterial culture, gel with bacterial culture and lyophilized gel with bacterial culture. The effect of the different treatments was compared with the negative control without the addition of PGPR, as different forms of treatments may achieve different efficiencies of rhizosphere colonization, which in consequence may have different effect on plant growth. To assess the effect of PGPR addition, soil physico-chemical characteristics (moisture content, pH) and growth characteristics of lactuca sativa such as number of leaves, height and width of aerial parts of these model plants were measured during the cultivation experiments. After the termination of the cultivation experiments, the basic growth parameters of the model plants from each treatment such as total plant length, length of aerial parts and roots of the model plants, as well as total weight of each plant and weight of their aerial parts and roots were determined. After drying, the total dry weight of individual plants and the dry weight of the aerial parts and roots were characterized. After drying, root density was analyzed by performing root scans and compared between treatments. Soil extracts from individual treatments after the cultivation experiments were analyzed to assess the effect of PGPR addition on the microbial activity of the soil used in the experiments by plate cultivation using Petri dishes with agar medium, and the average well colour development (AWCD) value determined using the BIOLOG EcoPlate kit. The obtained results were compared between the individual treatments and also between cultivation experiments conducted with different irrigation conditions. Physico-chemical characterization (pH, conductivity) was performed on soil extracts from the drained soils after the cultivation experiments. The amount of organic and inorganic fractions was analyzed on the dried soils of each treatment by TGA. The results were compared with each other and the effect of different forms of external addition of PGPR on the physico-chemical characteristics of the selected soil under conditions without irrigation limitation and under conditions with irrigation limitation during the experiments was assessed.
|
|
|
Study of plasma activated water effects on decomposition rate of organic matter using the “tea bag index” method
Bednařík, Tomáš ; Kalina, Michal (referee) ; Kozáková, Zdenka (advisor)
This bachelor thesis deals with the effect of plasma-activated water on the decomposition rate of organic matter using the tea bag index method. The first part of the theory of the bachelor thesis deals with plasma and plasma activated water. The second part deals with the tea bag index method and the analytical methods used in this thesis. In the experimental part, the aim of the thesis was to prepare plasma activated water using dielectric barrier discharge (DBD) and pin-hole discharge. Furthermore, to carry out the physicochemical characterization of plasma activated water, i.e., to determine the concentration of H2O2-, NO3-, NO2-, to measure its conductivity and pH, to determine the soil pH by two methods. The first method was determined using distilled water and the second using 0.2 M KCl. The last objective was to determine the rate of decomposition of organic matter using tea bag index and to assess the effect of plasma activated water on the physicochemical properties of soil. The results obtained indicate a positive effect on soil microorganisms and properties of plasma activated water. The next step in the investigation was to prepare a container experiment, produce and characterize plasma activated water for watering model plants, in this case lettuce.
|
|
|
Biochar effect on distribution of organic matter in soil
Haleš, Petr ; Širůček, David (referee) ; Kalina, Michal (advisor)
Biochar is a carbon-rich material that can be used in agronomy as a soil conditioner. The selection of the source biomass and the conditions used during pyrolysis (for example residence time and temperature) can have different effect on the physicochemical properties of this material. In this bachelor thesis biochar was produced from oat bran, woodchips, corn and compost by pyrolysis at 600 °C. The woodchips were also pyrolysed at temperatures in the range 400–700 °C. These biochar samples were subsequently leached with model rainwater. The main aim of this thesis was to assess how the conditions of biochar production influence the quantity and nature of substances, which can be released from this material. In the second part of this thesis, the commercial biochar Agrouhel (produced from sewage sludge at temperature 450–470 °C) was used (“Káňa”). This biochar was leached with model rainwater and dilute solutions of citric acid (which simulates root exudates) and hydrogen peroxide (which simulates enzymatic biochar degradation). Physicochemical characterization (pH and conductivity) of the extracts was realized after each leaching cycle. Additional analyses (UV-VIS and ICP-OES) of the solution were measured after the 1st, 5th and 10th cycle. The original solid biochar and biochar samples after the 10th cycle of leaching were used to determine the inorganic and organic fractions and to determine the elemental composition of the organic fraction (TGA and EA). The laboratory cultivation experiment with biochar Káňa was performed on the model plant (Lactuca sativa). Biochar obtained after termination of the cultivation was analysed (pH, conductivity, ICP-OES, TGA and EA) and the results were compared with data obtained for biochar Káňa leached by different model solutions. Fulvic and humic acids were extracted from the original biochar Káňa as well as from the biochar obtained after the termination of cultivation experiment. These samples were analysed on their inorganic and organic content and the abundance of organic elements (TGA and EA). Afterwards, the results were compared to each other and the correlations between the laboratory exposure to each soil factor and the cumulative exposure during the soil culture experiment were assessed.
|
|
|
Interaction of modified polymers with liposomes
Dimidova, Aleksandra ; Kalina, Michal (referee) ; Mravec, Filip (advisor)
The aim of this work was to investigate the interactions of modified polymers with vesicular systems, focusing on hydrophobically modified biopolymers. The work included a literature search, design of experiments to study these interactions, execution of the experiments and evaluation of the results in terms of potential medical applications. Different methods of preparing liposomes were studied in order to optimize their physicochemical properties for efficient drug delivery. Although the preparation of liposomes from DPPC faced problems due to the quality of chemicals, the ethanol addition method resulted in the formation of stable liposomes. These liposomes showed good size and stability, and their interaction with sodium palmitoyl hyaluronate indicated the potential for increasing the size of liposomes and affecting their stability.
|
|
|
Polyvinyl alcohol hydrogels with gradient structure in crosslinking density
Ščotková, Romana ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
The presented thesis introduce one of the many possibilities for the physical preparation of PVA hydrogels with a gradient in the crosslinking density. Based on the research conducted, the main focus of which was the preparation methods of gradient hydrogels and the characterization of their properties, a cyclic freezing and thawing method was selected and optimized with a focus on the selected preparation parameters. The next step was to perform pilot experiments leading to the confirmation and characterization of the resulting gradient structure by selected instrumental techniques such as rheology, scanning electron microscopy or a method based on monitoring the loss of dispersion during drying of the samples. In addition to the confirmation of the gradient structure, one of the parameters studied was the effect of the addition of polysaccharide on the resulting mechanical properties. Gradient hydrogels with different molecular weights or biopolymer additions were compared in the second part of the experimental work based on diffusion experiments using methylene blue. At the end of the work, all the results obtained were discussed and additional measurements were proposed for a deeper understanding of the subject.
|
|
|
Determination of the penetration of the active substances
Blažejová, Natálie ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This thesis is focused on the simulation of penetration of active ingredients used in cosmetic products. A theoretical part was written which focused on the basic characteristics of active ingredients used in the cosmetic and pharmaceutical industry. A method for the determination of these actives by means of Franz diffusion cells, which are used to determine the concentration of actives passed through the skin using different skin models, was described. The experimental part focused on the simulation of the penetration of two active ingredients, bisabolol and ectoine, which were provided by the cosmetic company Nobilis Tilia for this work. The amount of these actives was determined through Franz diffusion cells, using a synthetic Strat-M® membrane and a membrane prepared from pig ear skin. Furthermore, the tape-stripping method was used to determine the active substance in the skin layers. All samples were then analysed by UV-VIS spectrometry and liquid chromatography.
|
|
|
Transport and mechanical properties of hybrid hydrogel networks based on gellan
Sokolínský, Jan ; Pekař, Miloslav (referee) ; Kalina, Michal (advisor)
This diploma thesis deals with the characterization of the mechanical and transport properties of gellan based hybrid hydrogels. As part of this work, the process of optimizing the preparation of gellan-poly(vinylalcohol) IPN hydrogel was first studied with an emphasis on the repeatability of the preparation due to the preservation of mechanical properties of the hydrogel. Then, both on the gellan hydrogels themselves and on selected IPN compositions, the effect of various additives was studied (specifically, the effect of the addition of a plasticizer and the effect of cross-linking by polyvalent ions). Based on these tests, a set of samples was selected, on which dynamic mechanical analysis, swelling and drying experiments were additionally measured. At the end of this diploma thesis, the transport properties of selected hydrogel compositions were also studied. The tests conducted in this thesis revealed that both the formation of a dual network and the addition of the mentioned additives allow us to influence the studied properties.
|
|
|
Preparation and characterization of lignin modified by laccase enzyme
Hrušková, Lucie ; Obruča, Stanislav (referee) ; Kalina, Michal (advisor)
This master’s thesis focuses on the enzymatic modification of commercially available lignin using laccase enzyme and monitoring its impact on selected physical and chemical properties. Lignin is an attractive material for the production of renewable chemicals, materials, and energy, but its complex chemical structure poses a major obstacle to its effective utilization. Enzymatic modification appears to be a promising solution for its processing. Experiments were conducted under various conditions, such as pH, enzyme dosage, and reaction time. In the subsequent part of the experiment, the modified lignins were characterized and their results compared with those of the raw kraft lignin before modification. Molecular weight was determined using SEC-MALS, and the concentration of phenolic groups and antioxidant activity were measured. Structural changes were also monitored using FTIR. The results indicate that the enzymatic modification of lignin using laccase led to an increase in the molecular weight of the modified lignins, along with a decrease in the content of phenolic groups and a reduction in antioxidant activity. Based on the obtained results, it can be concluded that the action of the laccase enzyme resulted in lignin polymerization and the formation of new chemical bonds, leading to further aggregation.
|
|
|
Heat effects of microbial life in soil
Drápalová, Karolína ; Kalina, Michal (referee) ; Krouská, Jitka (advisor)
This research is intended to be an application of calorimetry to the study of thermal manifestations of microbial life in soil. Although this research has slowly but steadily expanded over the past half century, many unanswered questions still remain. Calorimetry is a suitable tool for determining several parameters of soil quality. Therefore, it is a very important indicator for agriculture. Very well-known indicators used in soil research can be measured by various calorimetric methods such as differential compensation calorimetry (DSC) and thermogravimetry (TG), which are temperature scanning methods used to estimate certain properties of soil material. Calorimetry can be used to determine the activity of microbial life in the soil, which is an essential parameter for the proper functioning of the soil, i.e. for its health. Microorganisms will release a certain amount of heat, based on their metabolism, which can be boosted by adding certain nutrients. We can therefore say that the presence of microorganisms in the soil can be detected thanks to calorimetry.
|
|
|
Application of superabsorbents in soil and its influence on plant growth
Závodská, Petra ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This thesis is focused on description of superabsorbents with controlled released of nutrients, specifically macronutrients nitrogen, phosphorus and kalium. Superabsorbents are polymers, mostly acrylic acid polymers, that can absorb huge amount of water without dissolving in it. In its structure they can hold water and thanks to this they are very perspective materials for agricultural usage. Experimental part was focused on growing corn with use of superabsorbents and control samples without use of superabsorbents. Plants were growth for 3 time periods, specifically 46, 60 and 74 days. During the experiments, plats were growth without water stress and in controlled conditions in growing box under UV lamp that simulated day and night by turning on and off after 12 hours. At the end, an image analysis was performed in HARFA program, from which we got information about branching of the roots. Results were supplemented by soil and plants analysis.
|
guest ::
RSS feed.