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Surface modification of glass fibers for polymer composites
Knob, Antonín ; Marek,, Aleš (referee) ; Burša, Jiří (referee) ; Čech, Vladimír (advisor)
The doctoral thesis is aimed at preparation of glass fiber reinforced polymer composites with controlled interphase formed by plasma-polymerized tetravinylsilane and tetravinylsilane/oxygen thin films. The thin polymer films of specific physico-chemical properties and thickness were deposited to improve interfacial adhesion of glass fiber/polyester composites. The fiber surface modification was performed by using plasma enhanced chemical vapor deposition in low-temperature RF plasma operating in an various effective power range and different treatment time. Test results were examined in relation to the interlayer thickness and different treatment conditions. The prepared interlayers were analyzed to evaluate physico-chemical composition and properties (XPS, RBS, ERDA, FTIR and spectroscopic elipsometry). Selected mechanical properties were evaluated by AFM. Mechanical response of plasma interlayers was evaluated by short beam shear test and direct method of testing the interfacial shear strength using microindentation. The interphase shear failure was controlled by the shear strength at the interlayer/fiber interface as follows from experimental and model data.
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Effect of high temperatures and different water regimes on selected winter wheat varieties above-ground biomass production
Hlaváčová, M. ; Klem, Karel ; Hlavinka, Petr ; Trnka, Miroslav
The aim of this study was to assess the effect of high temperatures and soil water scarcity during anthesis on the above-ground biomass allocation of the two winter wheat varieties (Bohemia and Pannonia). The six growth chambers were used to simulate heat stress conditions within following gradient of temperature maxima: 26°C (control chamber), 29, 32, 35, 38 and 41°C. The relative humidity (RH) course and photosynthetically active radiation (PAR) intensity were controlled via protocols. Additionally, drought stressed (Dry) and well-watered (Wet) treatments were established within each growth chamber. The plants were removed from the growth chambers after 14 days and they were left until a full maturity, exposed to ambient weather conditions. The spike productivities of the main spikes and harvest indices (HI) of the main spikes were evaluated for particular treatments within both winter wheat varieties after harvest.
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The effect of pyrethroid based pesticides on fish
RICHTEROVÁ, Zuzana
Pyrethroids are ones of the most used pesticides worldwides. The widespread use and high stability of pyrethroids lead to the assumption of that their occurrence in the environment could be quite frequent. They can reach water ecosystem as pollutants. Residues of pyrethroids are not only detected in the water column, but also in sediments and in fish tissues. The first study was devoted to the product Nexide containing 60 g.l-1 of active substance gamma-cyhalothrin. Tested Nexide concentrations were 5, 25, 50, 100, and 250 µg.l-1. Early life stage test was used.Common carp (Cyprinus carpio) was tested. There were significant mortalities in all concentrations except the lowest concentration during the trial. The lowest concentration tested 5 µg.l-1 only caused a slightly increased mortality. This lowest concentration influenced the growth in length and weight negatively, decelerated ontogenetic development, and made the body surface of the individuals darker. Histopathology of individuals from this concentration revealed dystrophy in liver. Examination of kidney, intestine and gills did not show significant histopathological differences compared with control. The evaluation of selected parameters of oxidative stress demonstrated a significantly higher activity of detoxification enzyme glutathione-S.transferase (GST) and a significantly lower activity of defensive enzyme glutathione peroxidase (GPx) compared with the control group. The other examined parameters of oxidative stress such as catalase (CAT), glutation reductase (GR), and lipid peroxidation determined by using the thiobarbituric acid-reactive substances (TBARs) were comparable to the control group. Changes in oxidative stress parameters suggest that exposure of the organism to the product Nexide in the given concentration leads to dysbalance of defensive enzymes. The second study was devoted to the product Cyperkill 25 EC containing 250 g.l-1. Tested Cyperkill 25 EC concentrations were 7.2, 36, 72, 144, and 360 µg.l-1. The procedure of the trial was the same as the preceded one. There were 100% mortalities in all concentrations except the lowest concentration during the trial. The lowest tested concentration 7.2 µg.l-1 allowed 90% of individuals to stay alive till the end of experiment. The lowest concentration influenced the growth in length and weight negatively and decelerated ontogenetic development compared with the control. Any individual exposed to this concentration did not reach juvenile stage until the end of the trial. Dark pigmentation was visible in 68% of these exposed individuals on the last day. Similar darkening was visible in individuals from higher concentrations shortly before death too. Histological examination did not revealed significant changes in intestine, liver, kidney, and gills compared with the control group. Evaluation of selected parameters of oxidative stress demonstrated significantly lower activities of GST, GR, and GPx. Activities of CAT and TBARS were comparable with the control group. Changes in oxidative stress parameters suggest that exposure of the organism to the product Cyperkill 25 EC in the given concentration could induce oxidative stress and interfere with the activities of antioxidant enzymes. The presented thesis summarises actual data about pyrethroids and their influence on fish. The demonstrated effects confirm high susceptibility of early developmental stages of fish to tested pesticides. When interpreting the results, we have to take into account the fact that studies showed this risk even on single pyrethroid substances. But water organisms are exposed to many other more or less toxic products and substances in a real environment. These xenobiotics could react with each other and their mixture could even potentiate negative effects. The performed studies also clearly show the significant differences in the sensitivity of embryonic and embryolarval tests.
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Cell culture-based model for the evaluation of adhesive properties of probiotic bacteria
Theodorou, Vasiliki ; Havlík, Jaroslav (advisor) ; Tauchen, Jan (referee)
Probiotic microorganisms, defined as living microorganisms which when administered in adequate amounts confer a health benefit to the host, and their adhesion and colonization of intestinal epithelium, are critical factors in maintaining probiotic efficacy. Polyphenols are a large and heterogeneous group of phytochemicals in plant-based foods, such as tea, coffee, wine, cocoa, cereal grains, soy, fruits and berries. In the last decade, there has been much interest in the health benefits of dietary plant polyphenols that arise from their potential ability to promote adhesion of probiotic bacteria to the human intestinal epithelium.
The purpose of this study was to investigate the effect of four polyphenols: isoquercetrin, phloretin, procyanidin B2 and rutin on the adhesion ability of two potentially probiotic strains (Lactobacillus casei, Lactobacillus gasseri) to in vitro human intestinal epithelial model consisting of Caco-2 and mucus-secreting HT29-MTX co-culture.
The adhesion of Lactobacillus casei after treating the co-culture cell lines with isoquercetrin, phloretin, and rutin was increased by 49.76, 72.97, 63.66 % respectively, whereas procyanidin B2 inhibited the adhesion 20.25% compared with the control sample. The adhesion of Lactobacillus gasseri after treatment of the co-culture with isoquercetrin, phloretin, procyanidin B2 and rutin was increased by 35.45, 31.28, 45.69, 25.01 % respectively compared with the control sample.
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Effect of water deficit on the energy content of individual plant organs in selected species of leafy vegetables
Šimůnková, Petra ; Hnilička, František (advisor) ; Česká, Jana (referee)
This work presents the impact of water deficit on dry mass production and photosynthetic accumulation of energy on every single plant´s organs of selected plant species. As a chosen experimental material were taken plants of Spinacea oleracea "Matador" sort and Tetragonia tetragonioides.
Spinacea oleracea and Tetragonia tetragonioides plants were grown in containers 11x11cm large in mixture of garden substrate A with silicon sand (2:1) in 2 variations placed in FAPPZ greenhouses. One variation was for control and second was exposed to stress reaction. Control variation had been watered for whole time of experiment with 50ml of water 2 times per week. Stressed one had been watered after puncturing and 6. taking until the end of experiment.
During the plant´s ontogenetic evolution had been monitored dry mass´s weight on singular plant´s organs. With usage of burnt calorimetry method had been monitored capacity of photosynteticaly accumulated energy in dry mass. Quantity of netto energy had been found out by dry burning adiabatic calorimeter LAGEST MS 10A.
From the gained results emerge, that plants of Tetragonia tetragonioides have 2 times higher weight growth apart from Spinacea oleracea. Control plants of Tetragonia tetragonioides have higher weight by 25,5% (123 mg) compared to the plants growing in water deficit. Likewise higher weight of roots had been observed on control plants (41 mg) compared to the stressed plants (40 g). Control spinach plants had higher weight of above-ground biomass by 19,5% compared to the stressed ones (43 mg). Roots of control plants had lower weight compared to stressed variant by 2960 mg.
From the results emerge, that plants of Tetragonia tetragonioides have higher weight of roots dry mass and above-ground biomass compared to the Spinacea oleracea plants.
Burning heat without ashes was on above-ground biomass of control plants Tetragonia tetragonioide on 15,96 kJ.g-1 level and on stressed plants 14,93 kJ.g-1 . In case of Spinacea oleracea plants was amount of control plants energy 14,98 kJ.g-1 and on stressed 14,21 kJ.g-1.
Burnt heat without root ashes of Tetragonia tetragonioides control plants was higher by 1.11 kJ.g-1 then on stressed ones (13,19 kJ.g-1). In case of Spinacea oleracea plants was amount of roots energy on control plants 11,90 kJ.g-1 and on stressed 11,72 kJ.g-1 .
Based on measurement were verified differences between species in reaction on water deficit and observed characteristic. From measuring emerged, that Spinacea oleracea plants are more sensitive on effect of water deficit compared to the Tetragonia tetragonioides
plants, which is more tolerant. Next thing observed is, that there are differences in amount of dry mass and rate of burnt heat in relation on effect of water deficit.
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Plant microclimate control
Jelínek, Jan ; Neděla, René (advisor) ; Papežová, Stanislava (referee)
This bachelor thesis discusses the management of a microclimate environment inside an
enclosed box. The aim of the work is to propose and implement a program for the
automized control of the microclimate. Microclimate management is ensured by a PLC
(Programmable Logic Controller) system utilizing the program Mosaic. Radishes
(Raphanous sativus L.) were chosen as the test plant. Optimal microclimate conditions for
the chosen test plant were achieved by programming the management system. The system
is easily adaptable, meaning endless different species of plants can be grown properly.
Healthy plant growth indicates the correct parameters of the microclimate.
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Effect of brassinosteroid and Atonik on growth of onion in different moisture conditions
Pařízková, Lada ; Doležalová, Jitka (advisor) ; Augustinová, Ludmila (referee)
Summary The aim of this study was to investigate the effect of synthetic brassinolide and Atonik, as a growth promoter supporting growth and development of plant that have been grown in different moisture conditions. For experiment were used two species of onion ('Alice'and'Lusy') which had been treated during the growth with synthetic brassinolide solution in concentrations 1.10-9 mol.l-1 and 1.10-11 mol.l-1 and 0.1% concentration of Atonik solution. For controlling was sown untreated variant. Average plant height and later diameter of the neck were observed and recorded during the experiment. Results showed that the product Atonik had in both variants positive influence on plant growth in deficit moisture conditions. Its effects have been later inconclusive or inhibitory. Brassinosteroid had positive effect on growth under optimal moisture conditions in "Lusy's" case and in stressful conditions in "Alice's" case. Brassinostreroid, unlike Atonik product, prevailed in neck diameter efficiency. In both cases, brassinosteroid had more positive effect on average yield in optimal moisture conditions. In deficit moisture conditions had Atonik product more positive effect on the yield of onion in both cases. To verify the results, it is necessary to repeat the experiment several time.
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Gas exchange characteristics in relation to genotypes in spinach (Spinacia oleracea) under water stress
Helebrantová, Aneta ; Hnilička, František (advisor) ; Pazderů, Kateřina (referee)
The bachelors dissertation was compiled on theme of: Gas exchange characteristics in relation to genotypes in spinach (Spinacia oleracea) under water stress.
Spinach (Spinacia oleracea) is, similarly as the others leaf vegetables, difficult crop in terms of providing the sufficient level of moisture, therefore the attention is drawn to the varieties of spinach which are resistant to the water stress. Thus the target of cultivation is to find plant which will be resistance to influence of the water stress.
In climabox of department of botanics and physiology was founded experiment with three species of spinach: Misano F1, Monores a Matador. The temperature mode was set to 21 °C during the day and 17 °C during the night. The light mode was set to 16 hours of light and 8 hours of dark per day. Maximum light level in climabox was 800 micromole. The plants were cultivated in 4 recurrences, diagram of experiment is involving two variants: control and stress. The plants in control variant were cultivated in substrate, which was irrigated during the whole time of experiment by 250 ml of water. For the plants in stress variant the supply of water was suspended for 10 days and the substrate was naturally continuously dehydrating. After 10 days the water supply was restored (rehydration) for plants in stress variant, same as level of control variant. The observation was made for the speed of gas exchange (photosynthesis and transpiration) in two-day interval. The speed of gas exchange was measured on leaf area with infrared gasometric gas analyzer Lpro+ (ADC Bioscientific, Hodeson, UK). Measured was conducted in morning hours according. Based on the measured values of photosynthesis and transpiration we calculated water usage effectiveness (WUE).
Based on obtained results is evident that the highest average speed of photosynthesis in control variant was observed at variety of Monores (12,10 micromole CO2.m-2.s-1) and lowest at variety Misano (11,58 micromole CO2.m-2.s-1). The highest average speed of photosynthesis in stress variant was measured at variety of Matador (9,43 micromole CO2.m-2.s-1) and lowest at variety Monores (8,76 micromole CO2.m-2.s-1). There was observed decrease of photosynthesis for each of variety during the water stress.
The highest average values of transpiration were observed at variety Monores (1,97 mmol H2O.m-2.s-1), lowest at variety Matador (1,68 mmol H2O.m-2.s-1). Stressed variety Misano reached level of photosynthesis 1,82 mmol H2O.m-2.s-1. Control variety Matador reached speed of transpiration 1,54 mmol H2O.m-2.s-1 and variety Monores 1,85 mmol H2O.m-2.s-1.Variety Misano was on same level of control variant as stress variant.
The most sensitively reacted variety Monores, which usage of water was 4,43 (10-3). Variety Matador managed the stress well, the usage of water was 5,60 (10-3).
Obtained results confirmed hypothesis of genotype differences depending on water deficit, thus there are differences between gas exchange and WUE in control and stress plants.
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Influence of term of winter rapeseed (Brassica napus) desiccation on yield and seed quality
Rajtmajer, Stanislav ; Bečka, David (advisor) ; Petr, Petr (referee)
Rapeseed is the world's third most important oil plant (the second seminal). It is the most cultivation and most important oil plant in Czech Republic. Winter rapeseed reaches about 85% of the harvest area of oilseeds in the country. The desiccation of oilseed crop is sphere of agricultural engineering, which is still worth discussing. The main problems are how to use the product, what dose and which dates to choose to desiccate. The results of this thesis could help to partially clarify this complex issue.
The aim of the thesis is to observe the effect of different terms oilseed rape desiccation by glyphosate on yield and seed quality.
Small-plot experiments to investigate the influence of the term desiccation of winter rapeseed were established in the years 2013/2014 and 2014/2015 on the lands of the experimental station of the Czech Agricultural University, Faculty of Agronomy Food and Natural Resources at the Červený Újezd.
In the first experimental year 2013/2014 was founded five variants in three replications (including undesiccated control). In the year 2014/2015 was founded seven variants in four replicates (including undesiccated controls). In the first experimental year was the first term desiccation 16. 6. 2014, the second year 8. 6. 2015. Subsequent periods of desiccation were a week apart.
The variety of winter rapeseed used for the experiments was a hybrid variety Rohan. The desiccating agent was used Dominator active substance glyphosate. The dose of
4 l / ha + 200 l H2O.
For all samples, both experimental, years yield was determined, the weight of a thousand seeds and oiliness. For desiccated variants were carried out pre-harvest analysis for the determination of solids in pods. Further, all harvested samples taken for laboratory germination test (Determination of germination) ISTA according to the methodology. The results of the experiment sprouting were statistically analyzed using ANOVA analysis of variance. Differences between mean values were evaluated by Tukey test, the computer program SAS at a significance level of p = 0.05.
Effect of desiccation term influences of winter oilseed rape seed quality in terms of weight and thousands of seeds in terms of oil content. Too early desiccation (46 to 39 days before harvest) HTS reduced by 7-17% and the oil content of 2-4% of the overall average. Oiliness of the observed characters minimum interference term desiccation. Desiccation in the optimum date (17 days before harvest) increased oiliness of 1-6%.
Influence term desiccation oilseed rape also greatly influences seed yield.
Too early desiccation (46 to 39 days before harvest) reduced the yield by 11-14%. Undesiccated control in both years achieved the highest yields, increase yield by 5-12%. Desiccation in the optimum date (17 days before harvest) increased the yield of attempts by 5-6%.
The term desiccation of winter rapeseed, also significantly affects the vitality of seeds, where very reduces energy germinating seedlings in the first days. The term desiccation, however, does not affect overall seed germination. Too early desiccation (46 to 39 days before harvest) EK2 decreased by 12-40%, EK3 decreased by 4-24%, 3-4% EK4 and extended MGT of 7-15%. In the first experimental year was the most vital option undesiccated control (EK2 = 50.4% = 91.3% EK3, EK4 = 97.9%). In the second experimental year was the most vital seeds of the optimal term desiccation, (Sixth term, 17 days before harvest) = 68.9% EK2, EK3 = 98.2%, EK4 = 100%. Seed samples of 2014/15 had a higher overall vitality of seeds, than samples from 2013/14, the overall vitality is probably worse given year old and transsilaged seed.
The results of the two-year experiment that term desiccation affects the quality of seeds, the yield of seeds and vitality of seeds. Pre-analysis was determined optimum solids content in siliques desiccated samples to values of 40-50%. Like most technology seems to desiccation in the optimum date (17 days before harvest) and agro technology without desiccated vegetation. As the least appropriate technology seems very early desiccation (46 to 30 days before harvest).
The first scientific hypothesis: Premature desiccation reduces seed yield, oil content and HTS. Yes, the hypothesis was confirmed.
The second scientific hypothesis: Desiccation made in the correct term do not affect the quality of the seeds (oiliness and HTS). Yes, the hypothesis was confirmed.
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