No description available.

No description available.

This thesis deals with the possibility of using evapotranspiration for efficient drying of wood. An important prerequisite is that the trees with good coppice pleated capability even after they are felled and physiologically active until they have enough water in the wood. The physiological activity sheets then accelerates the drying of wood. In search of work deals with familiarization with the problems of drying biomass possibilities of its use, and other definitions associated with this work. The main output of this work is to evaluate the decrease in water content in the wood poplar Populus maximowiczii x Populus nigra 'Max 1-5', chopped down just before the start of the growing season, due to evapotranspiration. In discussing data are compared with other available literature and summarized at the end of everything.

Among the most positive functions of trees in the cities are microclimate improvement and stabilization of slopes against erosion and landslides. The amount and distribution of water in the soil affect surface erosion and the stability of the slope. The aim of the study is to assess the influence of trees on the slope stability in a city park ‘Žižkovy sady’ in Hradec Králové. The study comprised of fieldwork, data processing, and hydrological modeling. During the fieldwork, the soils physical properties at the locality were studied under various types of vegetation cover. The soil moisture was measured under the trees and under the grassland from November 2015 to May 2017. Hydrological modeling in software PERSiST supported the soil moisture measurements, suggesting that trees have higher water uptake than other land use categories: grassland and paved area present in the locality. Modeled evapotranspiration was 30 % higher for trees than for grassland and 63 % higher for trees than for paved area, while total runoff for trees during the season was only 70 mm compared to 182 mm at the grassland and 447 mm at the paved area. The trees had a positive effect on the decrease of surface runoff through transpiration and interception, which mitigates of potential erosion and drains. Furthermore higher root diameter and rooting depth of trees than grass significantly improve slope ability. Potential tree removal on slopes of the locality may lead to increased erosion and landslides of existing slopes due to the excessive moisture in the low cohesive soils, the loss of anchoring roots and the increase of water infiltration into the soil.

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).

Abstract Evaluation of the effect of radiation on evapotranspiration estimates and drought indices The severity of drought can be inferred from water balance, of which evapotranspiration is a component. The evapotranspiration estimates are often based on the FAO 56 methodology with the net radiation as the main input. Usually, however, the latter is not directly measured. This study investigates to which extent can the direct solar radiation and the long-wave net radiation measurements be replaced by calculation according to FAO 56 with constant or locally optimised radiation coefficients or, for the long-wave net radiation, the coefficients according to Penman (1948). The problem is demonstrated on data from the Solar and Ozone Observatory in Hradec Králové for 2011 and 2012. On average, the estimates of solar radiation are satisfactory even with the standard coefficients and can be improved by local optimisation of the coefficients. The estimates for particular days may considerably differ from reality. The long-wave net radiation estimate according to FAO 56 is, on average, by about 30 % lower than the measured long-wave net radiation or an estimate thereof based on locally optimised or Penman's coefficients, with the average differences between any two of the last three methods much smaller (less than 9 %). The inaccuracy of estimates for particular days is considerable, too. The average reference crop evapotranspiration according to FAO 56 with standard coefficients is therefore considerably higher (by about 15 %) than analogous evapotranspiration obtained from the measured radiation or according to FAO 56 with optimised or Penman's radiation coefficients. The cause is that grass in the observatory was not irrigated. It therefore occasionally suffered from water stress and got overheated. The use of FAO 56 with the radiation inputs measured or calculated using other than the standard radiation coefficients may underestimate the evapotranspiration and the need for irrigation.

No description available.

The aim of proposed thesis is identification and assessment of the impact of various types of vegetation cover on microclimate and local climate. The thesis study an issue of vegetation cover impact on the solar energy transformation, energy fluxes and an impact of vegetation cover on water cycle, mostly at the landscape level. Temperature-humidity characteristics and energy fluxes and their indicators (Bowen ratio, evaporative fraction) were monitored during the growing season in common types of vegetation cover occurring in agricultural landscapes (red clover - Trifolium pratense L., common wheat - Triticum aestivum L., potatoes - Solanum tuberosum L. and permanent grassland (TTP)) and wetland with predominantly tall sedge vegetation (e.g. Carex acuta L., Glyceria maxima (Hartman). Holmberg.). Results show a direct correlation between solar radiation and the amount of energy converted into latent heat of evaporation or sensible heat flux expressed through evapotranspiration. The results of analyses confirmed the theoretical assumption that the vegetation cover significantly influences microclimate, e.i. air temperature and humidity both of itself and surrounding area. The temperature-humidity characteristics were significantly different in the monitored stands. From this findings is obvious that the different types of vegetation can affect local microclimate differently. Moreover, the results showed that the vegetation well stocked with water probably significantly affects the water cycle in the landscape.

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.

Stomata are structures in plant epidermis which regulate contact between inner and outer environment of the plant by mediating their stomatal aperture. Many inner and outer signals contribute to the ontogenesis of the stomatal pattern. Guard cells undergo significant change of volume and surface during stomatal movement. This change of surface must be compensated by intracellular trafficking of membrane material because biological membrane has limited elasticity. Most of this trafficking takes place between plasma membrane and endosomal compartments. Complex exocyst is protein complex that ensures proper targeting of secretory vesicles to their destination on the plasma membrane. Function of this complex is essential for many cellular processes that require precise targeting of secretion. Mutation in gene Exo70B1 causes different development of the stomatal pattern. Plants with mutated Exo70B1 differ in stomatal size depending on the cultivation conditions more than wild type plant. Protein EXO70B1 is also directly involved in stomatal dynamics because mutants exo70B1 have retarded stomatal opening in response to light. This direct connection can be observed on the fluorescently labeled protein EXOB1 which significantly changes its localization during stomatal movements. None of these observed phenotypes is...