The Physiology and Proteomics of Drought Tolerance in Maize: Early Stomatal Closure as a Cause of Lower Tolerance to Short-Term Dehydration?

Understanding the response of a crop to drought is the first step in the breeding of tolerant genotypes. In our study, two maize (Zea mays L.) genotypes with contrasting sensitivity to dehydration were subjected to moderate drought conditions. The subsequent analysis of their physiological parameters revealed a decreased stomatal conductance accompanied by a slighter decrease in the relative water content in the sensitive genotype. In contrast, the tolerant genotype maintained open stomata and active photosynthesis, even under dehydration conditions. Drought-induced changes in the leaf proteome were analyzed by two independent approaches, 2D gel electrophoresis and iTRAQ analysis, which provided compatible but only partially overlapping results. Drought caused the up-regulation of protective and stress-related proteins (mainly chaperones and dehydrins) in both genotypes. The differences in the levels of various detoxification proteins corresponded well with the observed changes in the activities of antioxidant enzymes. The number and levels of up-regulated protective proteins were generally lower in the sensitive genotype, implying a reduced level of proteosynthesis, which was also indicated by specific changes in the components of the translation machinery. Based on these results, we propose that the hypersensitive early stomatal closure in the sensitive genotype leads to the inhibition of photosynthesis and, subsequently, to a less efficient synthesis of the protective/detoxification proteins that are associated with drought tolerance

Time Series Analysis Of GDP and Market Indices

The paper is concerned with time series analysis of GDP growth and returns of securities market indices. The main goal was to identify cyclical patterns in the examined series and to demonstrate correlation among the individual series. First part of the paper presents deals with fitting the selected models to real data. Chapter 3 is devoted to correlation analysis. The analysed time series are quarterly GDP growth in the USA, in Germany and in the Czech Republic and monthly and quarterly returns of S&P500, DAX and PX50. All models applied in Chapter 2 are based on autoregressive processes. The analysis starts with linear ARMA model, followed by non-linear extensions thereof: the ARCH family based on conditional heteroscedasticity and the Threshold AutoRegressive Model (TAR). Non-linear models appeared to be more appropriate than simple ARMA models. Traces of cyclical patterns were identified in several time series, however, only US GDP growth and S&P500 seemed to be closely related in terms of cyclical behaviour. The correlation analysis confirmed two frequent hypotheses. First, returns on different capital markets in the world are strongly correlated reducing thus investors' possibilities to diversify risk. Second, the development of the Czech GDP growth and of PX50 responds (with certain delay) to the development of German GDP growth, whereas no correlation can be found between the Czech GDP growth and PX50 returns.time series, autoregressive models, correlation, econometrics, financial economics, dependence

Honour Disputes in the Seventeenth and Eighteenth Centuries

The theme of the presented bachelor thesis are disputes concerning honour in the years 1650-1750 on the Třeboň estate. This thesis aims at analysing honour disputes among inhabitants of townlets and villages on the Třeboň estate in the time in question on the basis of criminal law sources, suits of participants of the honour disputes, correspondence between the mayor and town council and top trustee of the estate. Actual participants of the honour disputes and the possibilities of the defence of their own honour will be in the centre of attention. Neither the characteristic surroundings in which the honour disputes took place nor the sort of defamations will be omitted. A typology of the defamations will be formed from the records of verbal offences. A particular honour dispute of an orphan named Sofie Renčová from Lomnice nad Lužnicí will be studied as well from the historical-anthropological perspective

The 2D gels showing the leaf proteomes of drought-stressed and control plants of two maize genotypes.

<p>S: drought-stressed; C: control; 2023: sensitive genotype; CE704: tolerant genotype. Only selected regions of the gels are shown; the frames mark the differences in the representation of two isoforms of the heat-shock protein HSP26 (spots nos. 4 and 5) in the drought-stressed plants of both genotypes. The protein spots that are differentially represented between genotypes and water treatments are marked by arrows and the respective numbers (1–11; N … unidentified protein) refer to the notation used in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0038017#pone-0038017-t003" target="_blank">Table 3</a>.</p

Five most up-regulated and down-regulated proteins in drought-stressed maize plants of 2023 and CE704 genotypes, as revealed by the iTRAQ analysis.

<p>The number in the column “CE704”, resp. “2023”, represents the n-fold increase or decrease in the protein content after 6 days of drought, derived from the ratio S_CE704/C_CE704 (resp. S₂₀₂₃/C₂₀₂₃) in case of the increased protein content and from the formula: –1/(S_CE704/C_CE704) (resp. –1/[S₂₀₂₃/C₂₀₂₃]) in case of the decreased protein content. ETC  =  electron transport chain; ZM  =  <i>Zea mays</i> L.</p

The differences in leaf proteins observed either between the genotypes or between control (C) and drought-stressed (S) plants of 2023 and CE704 maize genotypes, as evaluated by the 2D-electrophoresis method.

<p>AT  =  <i>Arabidopsis thaliana</i> (L.) Heynh.; ETC  =  electron transport chain; OEC  =  oxygen evolving complex of photosystem II; OS  =  <i>Oryza sativa</i> L.; LE  =  <i>Lycopersicon esculentum</i> Mill.; TA  =  <i>Triticum aestivum</i> L.; ZM  =  <i>Zea mays</i> L. The following symbols indicate the quantity of individual spots: –  =  absence, +/−  =  very weak intensity, +  =  medium intensity, ++  =  high intensity.</p

The functional classification of differentially expressed drought-related proteins from maize leaves.

<p>The number of proteins identified by the iTRAQ method in two maize genotypes (2023 and CE704) with up-regulated (<b><i>A</i></b>) or down-regulated (<b><i>B</i></b>) levels is shown; only those proteins whose levels changed due to drought in at least one genotype by at least twofold were included. ET: proteins of the photosynthetic electron-transport chain and chlorophyll synthesis; SM: proteins participating in photosynthetic carbon fixation and saccharide metabolism; MT: membrane proteins participating in transport; LM: proteins participating in lipid metabolism; AM: proteins participating in amino acid metabolism; DX: detoxification proteins; ST: stress proteins; DH: dehydrins; CP: chaperones; SG: proteins involved in cell signaling; PT: proteases and their inhibitors; GE: proteins participating in gene expression and its regulation; MS: miscellaneous proteins.</p

Phenotypic representation of drought-stressed and control plants of two maize genotypes.

<p>2023: sensitive genotype; CE704: tolerant genotype.</p

The gas exchange and water use characteristics of the leaves of drought-stressed maize genotypes.

<p>The net photosynthetic rate (P_N) (<b><i>A</i></b>), intercellular CO₂ concentration (c_i) (<b><i>B</i></b>), net transpiration rate (E) (<b><i>C</i></b>), stomatal conductance (g_S) (<b><i>D</i></b>), water use efficiency (WUE) (<b><i>E</i></b>) and relative water content (RWC) (<b><i>F</i></b>) in the leaves of two maize genotypes (2023 and CE704) that were subjected to 6 days of drought (solid bars) or normally watered (hatched bars). The means ± SD (n  = 18) are shown. The letters <i>a-c</i> denote the statistical significance (as determined by the Tukey-Kramer test) of the differences between genotypes/water treatments (only those marked with different letters differ significantly at p≤0.05).</p

Five proteins with the strongest contrast in the response to drought between 2023 and CE704 maize genotypes.

<p>The number in the column “CE704”, resp. “2023”, represents the n-fold increase or decrease in the protein content after 6 days of drought, derived from the ratio S_CE704/C_CE704 (resp. S₂₀₂₃/C₂₀₂₃) in case of the increased protein content and from the formula: –1/(S_CE704/C_CE704) (resp. –1/[S₂₀₂₃/C₂₀₂₃]) in case of the decreased protein content. The number in the column “Contrast” represents the difference between genotypes according to the ratio (S_CE704/C_CE704)/(S₂₀₂₃/C₂₀₂₃) in case of the higher protein up-regulation in the CE704 genotype/higher protein down-regulation in the 2023 genotype (upper part of the table). For the opposite situation (lower part of the table), the formula: –1/([S_CE704/C_CE704]/[S₂₀₂₃/C₂₀₂₃]) was used. AT  =  <i>Arabidopsis thaliana</i> (L.) Heynh.; ETC  =  electron transport chain; ZM  =  <i>Zea mays</i> L.</p