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Elevated temperature stimulates light-induced processes that contribute to protecting photosystem II against oxidative stress
Materová, Z. ; Štroch, Michal ; Holubová, I. ; Sestřenková, J. ; Oravec, Michal ; Večeřová, Kristýna ; Špunda, Vladimír
We focused on elucidating the impact of elevated temperature on rapid induction of zeaxanthin (Z)- dependent photoprotection in two different plant species. The dynamics of violaxanthin (V) de-epoxidation under different illumination regimes was studied together with chlorophyll a fluorescence transients in Picea abies seedlings and Arabidopsis thaliana leaves pre-acclimated to temperatures ranging from 20 to 40°C. Whereas for spruce seedlings the rapid phase of V de-epoxidation (induced by either 10 s illumination or 10 light pulses 1 s in duration at 1 min intervals) was gradually stimulated upon increasing temperatures, for A. thaliana leaves considerable acceleration of V de-epoxidation occurred only at 40°C. Moreover, only for spruce seedlings was a considerable amount of Z accumulated after 10 × 1 s illumination. Elevated temperatures stimulated rapid formation of Z-dependent non-radiative dissipation of excitation energy within photosystem II (NRD) induced by 1 s light pulses only for spruce seedlings. The possible role of a specific fatty acid composition in spruce thylakoid membrane lipids in facilitated V de-epoxidation and NRD induction at elevated temperatures is discussed.
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Ensolisation-silylation reaction study of selected steroids
Hehenberger, A. ; Kotas, Petr ; Tříska, Jan
For the purposes of trace analysis of 1,4-androstadiene-3,17-dione (ADD), 1,4-androstadiene-3-one-17β-ol (Boldenone) and 17-β-estradiol in water, waste water, soil and for the further phytosterols transformation studies the enolisation-silylation reaction was studied using MSTFA and BSTFA with different catalysts as derivatization reagents. The different reaction conditions and stability of the products was also studied using GC-MS technique.
Plný tet: Enolisation-sylylation reaction study of selected_2014_Hehenberger_Triska_SbornikCECE -  PDF
Plný text: content.csg - PDF
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Statistické vyhodnocení paralelního měření atmosférické rtuti dvěma identickými přístroji
Veselík, P. ; Dvorská, Alice ; Michálek, J.
Na Atmosférické stanici Křešín u Pacova, Vysočina, byly měřeny pozaďové hodnoty celkové plynné rtuti ve venkovním ovzduší dvěma automatickými rtuťovými analyzátory TEKRAN 2537B umístěnými vedle sebe v jednom kontejneru. Měření byla prováděna v 10minutových časových intervalech za období od prosince 2012 do srpna 2013. Cílem této studie bylo potvrdit, nebo vyloučit hypotézu o stejných výsledcích měření, poskytovaných těmito přístroji. Naměřené údaje byly seskupeny do týdenních intervalů. Byla provedena statistická analýza získaných dat. Data byla graficky znázorněna a vyhodnocena pomocí explorativní datové analýzy. Pro srovnání funkce obou přístrojů byla použita neparametrická statistická analýza (Wilcoxonův párový test). Provedená analýza ukazuje statisticky významné rozdíly mezi měřením obou přístrojů.
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Stem CO2 efflux on Norway Spruce trees: uncertainty in sap flow effect
Bužková, Romana ; Dařenová, Eva ; Acosta, Manuel
Uhlíková bilance lesa je dána dynamickou rovnováhou mezi procesy zabudovávání uhlíku (fotosyntéza atd.) a procesy uvolňujícími uhlík jako např. respirace. Právě respirace je důležitou složkou uhlíkové bilance lesa, protože uvolňuje až 80% uhlíku fixovaného v autotorofních a heterotrofních potravních řetězcích. S rostoucí teplotou prostředí respirace exponenciálně roste. Ovšem vlivy dalších faktorů na respiraci, jako např. transpirační proud, nejsou jednoznačně známé. Nárůst toku CO2 z kmene může být spojen s poklesem transpiračního toku (Levy et al. 1999), jeho nárůstem (Bowman et al. 2005) a nebo se vzájemně neovlivňují (Cerasoli et al. 2009). Cílem této případové studie bylo (i) zlepšení poznatků o potenciálním vztahu mezi traspiračním proudem a respirací kmene a (ii) průzkum faktorů prostředí potenciálně ovlivňujících tento vztah.
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Subseasonal temperature trends in Europe (1961-2000) and their links to atmospheric circulation
Cahynová, Monika ; Pokorná, L.
We use daily maximum and minimum temperatures and the daily temperature range from 136 stations in Europe in the period 1961–2000 to precisely locate their seasonal and subseasonal trends within the year. Linear trends are calculated for moving “subseasons” of 10, 20, 30, 60, and 90 days, each shifted by one day. Over most of Europe, the observed warming is greatest in winter. In Iceland and the Mediterranean, a pronounced warming is only present in summer. Significant autumn cooling was found in Eastern and Southeastern Europe for both TX and TN. Other non-warming periods occur in Western and Central Europe in February, April, and late June. Trends of DTR are inconclusive. Changes in the frequency of atmospheric circulation types usually explain a substantial part of the observed climatic trends; however, the influence varies between regions, times of the year, subseason lengths, numbers of circulation types, and input variables for the classification of circulation types.
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Mathematical methods of modelling the morphology of spruce trees
Janoutová, Růžena ; Novotný, Jan ; Pivovarník, Marek ; Zemek, František
Radiative transfer (RT) models are simulation tools which can be used to quantify relationships between vegetation canopy properties and observed remotely sensed data. Th is study aims at creating a spruce tree growth model as a key input for use in RT models. Th e spruce tree model is built on data obtained from terrestrial laser scanning of spruce trees. Each tree model is unique. Th is uniqueness is achieved by using L-systems which are able to simulate natural randomness while complying with the given tree parameters. L-systems are established on a theory of grammar that enables rewriting a string of symbols according to specifi ed rewriting rules. In practice, our tree models are generated in Blender visualization soft ware, implementing an algorithm written in Python. Th e algorithm generates the basic parameters of the whole tree and then creates the parameters of the spruce trunk and initial branches. Th e parameters are generated randomly within a range that is calculated from measured data. Th en each branch is grown on the basis of annual increments defi ned by fi eld measurements. Tree needles are distributed with respect to the age of individual branches; therefore, the needles have diff erent colours according to their age. Cones and faces are graphical representations of the spruce model. Branches are represented by cones and needles are represented by faces around the branches. Th e faces are transparent, thus simulating light transmittance in-between the needles. The whole model is highly computationally demanding, especially with respect to computer memory.
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Projections of future water-energy-vegetation regimes at the Lysina catchment, Czech Republic
Lamačová, Anna ; Yu, X. ; Duffy, Ch. ; Krám, Pavel ; Hruška, Jakub ; Farda, Aleš
Hydrologic models represent useful tools for the understanding of forest hydrological functions. At the Lysina Critical Zone Observatory (50°03’ N, 12°40’ E; area 0.293 km2), a forest catchment in the western Czech Republic, a distributed physics-based hydrologic model, the Penn State Integrated Hydrologic Model (PIHM), was used to simulate long-term hydrological change under forest management practices, and to evaluate the comparative scenarios of the hydrological consequences under anticipated climate change. Stand age-adjusted LAI (leaf area index) curves were generated from an empirical relationship to represent changes in seasonal tree growth. By considering the age-adjusted LAI, the spatially distributed model was able to successfully simulate the integrated hydrologic response from snow melt, recharge, evapotranspiration, groundwater levels, soil moisture and streamfl ow, as well as spatial patterns of each hydrologic state and fl ux variables. Corrected climatic data from the ALADIN-Climate/CZ regional climate model with SRES A1B scenario and diff erent forest age categories (Norway spruce monoculture) were used for projection of hydrologic pattern shift at the study site in the future (2025–2050, 2071–2100). Th e model projections suggested that that the decrease in mean annual runoff would be from 422 mm (observed in 1990–2011) to 361 mm (2021–2100) and 345 mm (2071–2100) with notable changes in seasonal patterns represented by a runoff decrease in the spring and summer months.
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Poplar-based short rotation coppice under artificially induced drought stress
Orság, Matěj ; Fischer, Milan ; Trnka, Miroslav ; Žalud, Zdeněk
The main aim of this study was to evaluate the diff erences in chosen microclimatological and ecophysiological variables between two types of experimental plots with diff erent levels of available soil water within a poplar-based (Populus nigra × P. maximowiczii) short rotation coppice plantation (SRC) during summer 2012. Diversity of sap fl ow, stomatal conductance and biomass increment were monitored between two treatments during the growing season of 2012. Th ere are 3 pairs of experimental plots under research. Each pair comprises a control plot and a neighbouring plot, equipped with a roof system, draining 40 % of the incoming rain water away (the water reduced plot). Our results show that a 40 % reduction in through-fall resulted in a 26 % reduction in transpiration and a 27 % reduction in stomatal conductance over the four month study period, which led to a statistically signifi cant (p = 0.03) deceleration of above-ground biomass accumulation at the plots with water-reduced treatment.
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