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Maize is one of the most profitable crops in our country. Therefore, new technological processes are implemented and developed at growing maize. Despite the relatively extensive knowledge and experience in growing maize, these technologies are abundant with risks and possible pitfalls. A very important question above all is the one concerning the soil treatment; fertilization and nutrition suitable for maize growing. Thesis deals with proposing an appropriate system of fertilization the maize suitable for silage by all different means of wide fertilization applications, fertilization supplements at the base and at the top with relation to production of silage. During the vegetation, we took measurement of maize plants. Thesis also evaluates the intensity and volume of chlorophyll in leaves of maize that was not treated. The experimental plants of maize were situated on testing field of Research Station, Faculty of Agronomy. Food and Naturall Resources at the Czech Agricultural University in Prague in Červený Újezd (district Prague - West). After the harvest, all variants of maize were examined from the perspective of profit in green state and in the dry state. Within the one-year experiment, we found following results that may help in the planning the basic or supplemental fertilization of silage maize. Therefore, based on the results launched, we present that the wide top use of Zeastim fertilizers in combination with Urea Stabil fertilizer has impact on higher growth of green mass, so it proves higher profit of green and dried mass.

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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.

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The main objective of this study was to determine the effect of elevated CO2 and drought on growth of fast-growing trees, hence hybrids of poplar Populus nigra and Populus maximowiczii on experimental station Domanínek. These parameters were measured: photosynthesis, reflectance, fluorescence of chlorophyll and content of chlorophylls and flavonols. The results show a demonstrable effect of greater regulatory abilities stomatas at elevated CO2 concentration, which leads to greater efficiency of water use. Decisive influence on leaf area, specific leaf area and the dry weight has the effect of drought. However, for specific leaf area, contrary to expectations, there was an noticeable increase during drought period. In the case of other characteristics come to reduce them. By contrast specific leaf area slightly decreases at elevated CO2 concentration. Rate of photosynthesis increases with increasing concentrations of CO2, while the effect of drought dampens these characteristics and also reduces the chlorophyll content. Increasing concentration of CO2 during the experiment also leds to an increase in NDVI index, which shows increased chlorophyll content. The values of fluorescence at two concentrations of CO2 when exposed to drought stress differed minimally. The maximum quantum yield of photosystem II is slightly higher at elevated CO2 concentration. Overall, it can be summarized that in the short-term effect of drought stress in hybrid poplar, increased concentration of CO2 increases water use efficiency and thus to mitigate the impact of drought on photosynthetic parameters.

The purpose of this thesis is to obtain informations about the parameters of environment, which increases respiratory processes in fishponds and can cause an oxygen deficit. 24 monitored lakes were chosen according to the requirements of Rybářství Třeboň a.s. Between 4. 2. 2014 and 30. 9. 2014 took place 10 samplings. Water samples were taken for chemical laboratory analysis. At the same time there were made field measurements of basic physico-chemical parameters - dissolved oxygen concentration, temperature, color and transparency. Laboratory analysis determined compound and forms of nitrogen, phosphorus, carbon and the quantity of chlorophyll-a. Plankton respiration per 24 hours was detected by measuring the oxygen consumption by plankton in sizes up to 235 microns. Relations between respiration and other parameters, and different concentration of dissolved oxygen at the surface and in the depth of 1 m and the other parameters were compared using regression and correlation analysis. The observed decreasing trend of the seasonal oxygen saturation indicates that whole fishpond is dominated by respiratory processes. The results of correlation analysis, comparing the relationship of environmental parameters and respiration pelagial per 24 hours, shows that respiration correlates most with organic carbon content (representing the amount of organic substance). Furthermore, positively correlates content of total nitrogen, the amount of phytoplankton expressed as chlorophyll-a concentration and transparency. Content of particulate and total nitrogen, amount of phytoplankton and transparency also positively correlated with respiration. Total phosphorus concentration correlates with the respiration least of the monitored parameters.

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.