Gloiopeltis furcata (Postels & Ruprecht) J. Agardh, a macroalga, which grows in an upper, intertidal zone, can withstand drastic environmental changes caused by the periodic tides. In this study, the photosynthetic and morphological characteristics of G. furcata were investigated. The photosynthetic performance and electron flows of the thalli showed significant variations in response to desiccation and salinity compared with the control group. Both PSII and PSI activities declined gradually when the thalli were under stress. However, the electron transport rate of PSI showed still a low value during severe conditions, while the rate of PSII approached zero. Furthermore, PSI activity of the treated thalli recovered faster than PSII after being submerged in seawater. Even though the linear electron flow was inhibited by DCMU [3-(3, 4-dichlorophenyl)-1,1-dimethylurea], the cyclic electron flow could still be restored. The rate of cyclic electron flow recovery declined with the increasing time of dark treatment, which suggested that stromal reductants from starch degradation played an important role in the donation of electrons to PSI. This study demonstrated that PSII was more sensitive than PSI to desiccation and salinity in G. furcata and that the cyclic electron flow around PSI played a significant physiological role. In addition, G. furcata had branches, which were hollow inside and contained considerable quantities of funoran. These might be the most important factors in allowing G. furcata to adapt to adverse intertidal environments., L. Huan, S. Gao, X. J. Xie, W. R. Tao, G. H. Pan, B. Y. Zhang, J. F. Niu, A. P. Lin, L. W. He, G. C. Wang., and Obsahuje bibliografii
The paper presents the results of research of surface water and sediment contamination by the specific pollutants in the Klabava River Basin, subcatchment of Vltava River in Central Bohemia, Czech Republic. The analysis of spatial and temporal dynamics of the contamination is based on the water and sediment chemistry data from the long-term monitoring maintained by the Vltava River Authority completed by the own monitoring established in the Klabava River basin. The research revealed that the most important water and sediment contamination loads are mainly concentrated in the industrial area between cities Hrádek and Rokycany situated on downstream of the river basin. The performed analysis identified the cadmium as the most critical parameter as its concentrations in surface water exceeded the references limits up to several hundred times. However, pollution with the specific organic substances was still below the critical limit, except for the AOX indicator. The results of sample-taking in the river basin allowed analyzing the effect of extreme flood in August 2002 on the changes in the sediment load by heavy metals. Contaminated sediments were mostly washed out by the inundation and this resulted in significantly lower values than were observed in the previous seasons. Repeated observations however indicate that the pollution concentrations are gradually reaching their original values. and Článek představuje výsledky výzkumu znečištění povrchových vod a sedimentů specifickým znečištěním v povodí Klabavy. Analýza vychází z dostupných dat o chemismu vody a plavenin ze sledování podniku Povodí Vltavy a z vlastních dat získaných rozbory vzorků odebraných na síti účelově zřízených profilů. Pro hodnocení chemismu sedimentů byly použity standardní metody - porovnání s pozaďovými hodnotami geogenního prostředí podle Turekiana a Wedepohla a zatřídění do tříd jakosti podle Igeo. Z výsledků vyplývá, že zatížení vody i sedimentů je soustředěno zejména do oblasti průmyslového a sídelního uskupení mezi Hrádkem a Rokycany. Varovné jsou zde především koncentrace kadmia ve vodě, které v této oblasti překračují referenční hodnoty i několiksetkrát, silnou zátěž potvrzují i analýzy sedimentu. Znečištění specifickými organickými látkami s výjimkou ukazatele AOX nedosahuje kritických hodnot. Výsledky vlastních odběrů umožnily rovněž zhodnotit vliv povodně v srpnu 2002 na změnu zátěže sedimentů. Kontaminované sedimenty byly povodní vyplaveny a hodnoty, naměřené bezprostředně po povodni, jsou výrazně nižší než v předchozím období. Díky pokračující zátěži se však postupně vrací k původním hodnotám.
The specificity factor of Rubisco (S f) was estimated in intact leaves from the carboxylation of ribulose-1,5-bisphosphate (RuBP) at various CO2/O2 ratios. As oxygenation is calculated by the difference of the 14CO2 uptake by RuBP in the absence and presence of oxygen, it is important to choose the optimum CO2/O2 ratios. At high CO2 concentration (1,000 cm3 m-3 and higher) oxygenation consumes less than 50% RuBP but the difference of concentrations of CO2 at cell walls (Cw) and at the carboxylation centers (Cc) is 2-5% and the influence of mesophyll resistance
(rmd) is of minor importance. To accumulate large endogenous pool of RuBP, the leaves were preilluminated in the CO2- and
O2-free gas environments for 8 to 10 s. Thereafter the light was switched off and the leaves were flushed with the gas containing different concentrations of 14CO2 and O2. The specificity factor of Rubisco was calculated from the amount of the tracer taken up under different 14CO2/O2 ratios by the exhaustion of the RuBP pool. Application of 14CO2 allowed us to discriminate between the CO2 uptake and the concurrent respiratory CO2 release which proceeded at the expense of unlabelled intermediates., J. Viil, H. Ivanova, T. Pärnik., and Obsahuje bibliografii
The attention is directed on some specific basic concepts, quantities, ideas and mathematical relations of pulse radar signal analysis and processing under stationary linear polarized high-frequency harmonic supporting electric component. The text contains the definition of a monofrequency radar pulse and its complex representation, interpretation of the radar resolution cell volume, Fourier transform alternatives of a radar signal, explaining the principle and parts of its uniform digitalization, vector and matrix representation of a discrete pulse radar signal, reason and purpose of its processing data correction, and comment of kinds and use of similarity correlations of its pair forms., Pozornost je zaměřena na některé specifické základní pojmy, veličiny, představy a matematické relace analýzy a zpracování pulzního radarového signálu se stacionární lineárně polarizovanou vysokofrekvenční harmonickou nosnou elektrickou složkou. Text postupně obsahuje vymezení monofrekvenčního radarového pulzu a jeho komplexní reprezentace, interpretaci rozlišovací buňky radaru, alternativy Fourierovy transformace radarového signálu, vysvětlení principu a složek jeho rovnoměrné digitalizace, vektorovou a maticovou reprezentaci diskrétního pulzního radarového signálu, zdůvodnění a účel korekčního součtu dat při jeho zpracování a vysvětlení druhů a užití srovnávacích korelací jeho párových forem., and Pokračování v příštím čísle
A theory of spectra and excitation dynamics in antenna based on the notion of exciton interactions in the cyclic structures of light-harvesting pigments is reported. The theory provides an explanation for the picosecond absorbance difference spectra, the induced absorption anisotropy decay, the anomalously high bleaching valné, as well as for the fluorescence spectra, kinetics and depolarizatio