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The harmful influences on plants are called stress factors. The stress itself does not slow down only vital functions of plants but influences directly the size and quality of final product as well. Worldwide, we count the so called abiotic stresses as the most significant crop production stressors. These include in recent years extremely high temperatures and unequal rainfall distribution both areal and during vegetation period. The water deficit (drought) belongs to the most important stress factors in agriculture. It influences crop production all over the world. Also vegetables are responsive to water deficit, especially the species with huge amount of water in their tissue. Therefore, the goal of this thesis is to assess the impact of water stress on gas exchange and photosynthetic activity of mangold "Beta vulgaris", salad rocket "Eruca sativa" and lettuce "Lactuca sativa", which were placed at water deficit. The plants - mangold, salad rocket and lettuce - were grown in a partly controlled greenhouse conditions under the Department of Botany and Plant Physiology FAPPZ ČZU in Prague. The plants were grown at a temperature of 25°C in daytime and 18°C at night under natural light conditions. They were grown in containers of size of 11x11 cm in a mixture of garden substrate A and silica sand in the ration 2:1. The experimental scheme included two variants - control and stressed. The control group of plants was watered, and the second half of plants was left under stress for 22 days, when the water deficit was induced by gradual drying for one month, the experiment took place from 1.6 2015 to 22.6 2015. The speed of gas exchange by plants was measured by apparatus LCpro+. From the values of photosynthesis and transpiration water use efficiency (WUE) and chlorophyll fluorescence were calculated. The gained results proved difference at reaction to water stress between observed kinds of leaf vegetables. The speed of photosynthesis and transpiration of observed plant species was measured, which decreased due to impact of water deficit. The average speed of photosynthesis of stressed plants was the lowest by lettuce (11,16 "mikro"mol CO2.m-2.s-1), contrarily the highest by mangold (13,2"mikro"mol CO2.m-2.s-1). In case of control plants was the lowest speed of photosynthesis noticed by lettuce (12,03"mikro"mol CO2.m-2.s-1) and the highest by mangold (14,00"mikro"mol CO2.m-2.s-1). In comparison with control group, the speed of photosynthesis of lettuce decreased significantly by impact of water deficit (difference make 7,23 %). On the other hand the lowest decrease of photosynthesis from stressed plants 5,93% was noticed for mangold. In case of speed of transpiration, it is possible to note, that the lowest transpiration of control group shows mangold with the average speed of transpiration 1,82 mmol H2O.m-2.s-1, by contrast the highest transpiration was measured by lettuce 3,20 mmol H2O. m-2.s-1. In the case of stressed plants moved the average speed of transpiration between 1,54 mmol H2O.m-2.s-1 for lettuce and 1,79 (mmol H2O.m-2.s-1) for mangold. Also, between control and stressed plants of the same species were found differences, and salad rocket reacted to stress of drought more sensitively and mangold less sensitively. For these two plant species was noted decrease of transpiration in the amount of 23,80% and 1,76%. From the measured value of photosynthesis and transpiration was calculated water use efficiency (WUE). The calculated values show that stressed plants have higher value of WUE in comparison to control plants. The lowest water efficiency from control plants produced salad rocket (6.51 x 10-3), while the highest mangold (10.31 x 10-3). In the case of stressed plants was the lowest value of WUE noted for salad rocket (8.96 x 10-3), while for mangold was the highest (10.71 x 10-3). Chlorophyll fluorescence of the experimental plants was also measured. This characteristic was not influenced by plant species, because in case of control plants, there were no differences found between observed plant species. The lowest difference in value of fluorescence had plants of lettuce (0,69) while the highest mangold and salad rocket (0,7). In conclusion it is possible to note, that more sensitive to water deficit are plants of lettuce. As more tolerant to water deficit seems mangold and salad rocket.

Summary The thesis studied the effect of water deficit on gas exchange in young plants sorghum and foxtail. These crops could replace maize cultivation in some areas, because their use is similar. Our country is currently facing shortage of rainfall. In 2015, this phenomenon was very noticeable. Therefore, it is appropriate to see how the plants of sorghum and foxtail respond to water deficit during their ontogenetic development. On the water deficit are very sensitive plants in the early stages of growth, and therefore the influence of water deficit was observed on young plants of sorghum and foxtail. Plant genotypes 121, 304, Ruzrok Red and Plant foxtail were divided into four variants: KK (fully irrigated throughout the experiment) KS (14 days full of grout, 10 days water deficit, 4 days full dressing), SK (10 days water deficit, 18 days full of dressing), SS (10 days water deficit, four days filled with grout, water deficit 10 days, four days full of topping). The speed of exchange of gases were measured in the greenhouse device LCpro+ and chlorophyll fluorescence apparatus OS1 - FL. The rate of photosynthesis and transpiration and chlorophyll fluorescence were measured in the morning. The difference between the measured values of the rate of photosynthesis and transpiration value was calculated water use efficiency (WUE). Most sensitive to water deficit responded genotype 121 which had a value of water use efficiency (WUE) 9.95 (10-3) and also had the genotype and the lowest value of chlorophyll fluorescence and 0.765. Resistant to water deficit seems foxtail plants, which had the lowest photosynthesis difference between control and stressed variant in the range of 14.59 mikromol CO2.m-2.s-1 (SS) to 15.38 mikromol CO2.m-2.s-1 (KK). At the same time it also foxtail lowest difference between chlorophyll fluorescence variant KK (0.814) and SS variant (0.781). From the perspective of transpiration as most resistant to water deficit appeared foxtail (0.08 mmol H2O.m-2.s-1 (SS) to 2.13 mmol H2O.m-2.s-1 (KS)). Conversely, the least resistant genotype was 121, which was in the control variant 1.17 mmol H2O.m-2.s-1 and stressed 1.50 mmol H2O.m-2.s-1.

At growing Saaz variety is the target to reach the highest yield of hop´s cones and high content of alpha acids. The average content of this acids in Saaz variety is in the range from 2,5 to 4,5 %. The growers effort is to reach the higher number of this range because the final selling price is given by content of alpha acids. During the active growth of hops, grower can targeted stimulate the hops to positively affect the physiological processes. Then he can reach better yield of valuable alpha acids and that´s why the target of this diploma thesis was to fix the influence of growth stimulators on physiological processes on the yield of hop´s cones and the yield of alpha acids. And based on the results to identify the suitability of using growth stimulators during the intense hops growing. Following scientific hypothesis were designed: determine the plants reaction diversity on growth stimulator. For reaching the targets and confirm or reject the hypothesis was observed in natural conditions nearby the Chrastany region the plants of Saaz (clone 72) in interaction with the usage of growth stimulators. These stimulators were used: Humastar, Fertileader Vital, Lignoaktivátor. There were four variants: controled with no aplication and three other variants with usage of growth stimulators (for each variant were apllied only one stimulator for three times). The influence of growth stimulators on hops plants (phase BBCH from 37 to 81) was observed on the basis of the rate of gas exchanges, chlorophyl fluorescence and the leaves chlorophyl content, which were measured by infrared gas analyzer LCpro+ (ADC BioScientific Ltd. Hoddesdon, Great Britain), OS 1-FL (OPTI SCIENCES), Chlorofyl CCM 200 ADC BioScientific Ltd. Hoddesdon, Great Britain) After the crop was evaluated the yield of hop´s cones and the content of alpha acids, beta acids and essentials oils. The results of measurment indicates that the highest average transpiration rate was observed after Humastar application (+18,3 % against control variant). In the control variant was found the lowest average transpiration rate from all variants. The highest photosynthesis rate was found after Fertileader Vital application (+7 % against control variant). Decrease of photosynthesis rate about 17 % against the control variant was observed after Humastar application. The differences was also observed in chlorophyll fluorescence. The highest Fv/Fm value reached the hop´s plants after Fertileader Vital application, concretely 0,792. On the other hand the lowest Fv/Fm value was observed after Lignoaktivátor application (0,780). After the application of all tested growth stimulators were reached increase of a pigment´s content in hop´s leaves against the control variant. The highest content of pigments were observed after Fertileader Vital application (+19,2 % against control variant). Control variant reached the average content of pigments in hop´s leaves 25,5 chlorophyll units. Differences after the growth stimulation was also observed in yield and quality of dry hop´s cones. The highest yield reached the Lignoaktivátor variant (0,73 t/ha). This is an increase of 17,7 % against the control variant (0,62 t/ha). The yield of hop´s cones was decreased of 8,1 % against the control variant after Humastar application. The similiar trends were also observed in hop´s cones quality. The highest content of alpha acids (3,06 %) was reached after Lignoaktivátor application and at the same time Lignoaktivátor variant also achieved the highest content of essentials oils per 100 g of a sample (0,22 ml). Humastar variant had the lowest content of alpha acids (2,18 %) and also the lowest content of essential oils (0,14 ml). Based on the results it can be stated that the used growth stimulators had the influence on the physiological characteristics of hop´s plants and also affected the different yield and quality of hop´s cones. Proposed hypothesis were confirmed. Based on the one-year results, application of Fertileader Vital or Lignoaktivátor seems to bee more profitable than Humastar application.

Summary Water resources are an important part of ecosystems. In the water balance of the landscape, the variability of climate, soil factors, as well as high diversity of vegetation play an important role. Evapotranspiration represents a major passive component in the water balance of the basin. Unlike forests, where the water balance is particularly predictable due to the long-term development of the stands, regular crop rotation in agricultural systems and agricultural practices may cause rapid changes in water balance during much shorter time. It may sometimes result in irreversible changes in ecosystems with impact on landscape biodiversity. An understanding of the limiting environmental factors and exact determination of the water demands of plants makepossible not only an improvement of yield parameters, but it is also condition for understanding of the agroecosystems sustainability in the cultural landscape. Field measurements of actual evapotranspiration were carried out in the period 2007 to 2015 in Velvary (Budihostice) in the Central Bohemia region, 210 m above sea level in the rain shadow area around Slaný territory. In terms of the average annual water balance (CHMI, 2014), the locality is regarded as the area with the difference between the average annual precipitation and annual potential evapotranspiration totals in amount of -200 mm, so the potential evapotranspiration slightly exceeds precipitation. Field measurements were conducted on commonly managed areas with a minimum size of the experimental plots of 1 ha. The measurements confirmed differences between the crop water demands during the growing season. Different values of the actual evapotranspiration as well as the Bowen ratio values were estimated for the observed crops depending on the growth stage of crops. The lowest values of actual evapotranspiration were detected for Zea mays and Sorghum bicolor. Higher water demands were shown by Triticum aestivum and Hordeum vulgare. On the contrary, the highest values of actual evapotranspiration were found in stands of Beta vulgaris and Medicago sativa. According to the values obtained for crop coefficients (Kc), the crops of Z. mays, S. bicolor and T. aestivum had about a quarter lower values of Kc compared with M. sativa and B. vulgaris crops in the main growing season. In this work, the daily values of Kc, which are the basic characteristics of moisture requirements for individual crop were determined and can be used modelling of hydrological processes in agro-phytocoenoses. The evaluation of moisture requirement of crops by the water flow in plants (determined by the sap flow method) showed the expected differences between S. bicolor and Z. mays plants. Water use efficiency (WUE) was significantly higher in plants of C4 type (Z. mays and S. bicolor) compared with the rest of observed plants of C3 type (T. aestivum and H. vulgare).

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Non-metabolic use of solar energy in plants can be seen as plant thermoregulation driven directly by solar irradiance. Adaptations leading to warming up are particularly important in cold habitats. Cooling processes are needed everywhere where there is short-term or long-term excess of solar energy. Plants are of utmost importance for ecosystem and landscape functioning. Vegetation has a potential to regulate the Earth{\crq}s surface temperature and improve conditions for other living organisms. By regulating energy and water fluxes between land surface and the atmosphere vegetation is closely related to the climate system.

The literary part of the thesis contains basic information on the tomato (Lycopersicon esculentum Mill.) hydroponic culture and the nutrient solution parameters for hydroponic culture of the tomato. A big part of the thesis is dedicated to the photosynthesis process, its phases and factors affecting the process. It also describes various methods of photosynthesis related parameters. The chapter titled methodics records the observed varieties and the conditions they were cultivated in. The devices used to measure as well as the experiment methodology are described in the thesis. The practical part of the thesis is dedicated to observing physiological characteristics of the tomato such as: the photosynthesis intensity, transpiration levels and the stomatal conductivity of gaps. All characteristics were measured at spot conditions of the plants.

The thesis was intended to fill the information gap in the ecohydrology of the Pinus rotundata dominated peatbogs in the Třeboň Basin Biosphere Reserve, Czech Republic by studying various aspects of their water régime (i.e., transpiration of the dominant tree species, soil water chemistry, retention ability). The study is based on regular monitoring of the water table, water discharge, soil water chemistry and precipitation (during 1995-2000, study sites Červené blato and Žofinka peatbogs). Additionally, the transpiration of adult Pinus rotundata trees was measured in the field during 1999-2000 at the experimental plot in the Červené blato peatbog (330 ha, 465-475 m a.s.l.). Nowadays, the Pinus rotundata-dominated peatbogs represent almost natural (peaty) forests inside of otherwise human-made forest plantations. Long-term vegetation changes after natural disturbances such as windstorms, insect infestation and fire are only occasionally reported for the central European natural forests. Therefore the evaluation of vegetation changes after disturbances, typical of boreal forests, and their impact on peatbog hydrology has also been included in this thesis (study site Žofinka peatbog, 130 ha, 470-475 m a.s.l.). Transpiration of the central European endemic tree species, Pinus rotundata Link, was...

This dissertation is concerned with the foundations in volume unstable soils and objects disorders which are related to this. The thesis was focused on the study of clay and loess soils which are abundant in the geological profile of the Czech Republic. First, the formation of the two groups of soils is introduced, then their properties are examined and finally the influence of vegetation on the former type and the influence of collapsibility in the latter type are investigated. The conclusion is, in fact, a recommendation on the design of structures so that the system of clay / structure is not damaged and that structures are not subject to renovations. Several instance of problems with structures are discussed which were subject to structural repairs employing both a civil and geotechnical engineers.