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- Author or Editor: O. Mészáros x
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The large-scale archaeological excavations of the past years yielded a rapid increase of archaeological finds and observations. This large amount of new evidence enabled the observation of wider environmental archaeological relationships. In the study we reconstruct certain environmental and settlement pattern changes from the 13th to the 18th centuries based on archaeological data from the southern shore of Lake Balaton and the cities of the Danube Bend region. The settlements on the shore of Lake Balaton and along the Danube reacted similarly, but with a temporal lag. Hydroclimatic changes caused a shift in the location and structure of lake- and riverside settlements, which was of a horizontal character in the case of Lake Balaton, and of a vertical character in the case of the Danube Bend region.
The saline area of the Kiskunság region of Hungary has varied micro-topographic conditions with different plant communities. This study was performed in a dry sandy grassland community ( Potentillo arenariae-Festucetum pseudovinae Soó (1938) 1940) and a neighbouring saline sandy grassland community ( Lepidio crassifolii-Puccinellietum limosae Soó (1947) 1957). These are located at different elevations and have completely different floristic composition and physiognomy due to the soil characteristics and water availability. We assessed how the different environmental conditions during summer period might alter some physiological traits of two dominant xerophytes of sandy grassland ( Achillea collina L., Festuca pseudovina Hack. ex Wiesb.) and two halophytes of saline grassland ( Lepidium crassifolium (W. et K.), Puccinellia limosa (Schur) Holmbg.). The relationship between soil water potential and water content showed lower water availability for plants in the saline habitat as the high water soluble sodium content (900–2000 ppm) of this soil type limits water absorption. Both halophyte species in this study exhibited lower K/Na ratio than xerophyte species. Between the two halophytes L. crassifolium can be described as a “leaf/shoot sodium accumulator” species while P. limosa as a “leaf sodium avoider” species. The four species differed in proline accumulation. The salt adapted species had multifold accumulation of proline as compared to species of dry sandy grassland. The three microhabitats differing in total plant cover offered different microenvironmental conditions for L. crassifolium . Proline content was twice higher in leaves of this species in the microhabitats with high soil Na + content than in the closed microhabitat. Every species showed a transient reversible decrease of potential photochemical efficiency of PSII (F v/ F m ) at midday during the study period. In the saline habitat the midday depression of F v/ F m for L. crassifolium was much larger than in case of P. limosa which reflected its higher susceptibility to photoinhibition. In sandy grassland F v/ F m of A. collina was smaller than that of F. pseudovina . Mesophyll succulence index (Sm) expressing the ratio of water content to chlorophyll content was the highest in L. crassifolium (1.6–2.2 g H 2 O mg −1 Chl). Sm was low in xerophyte species (0.5–1.1 g H 2 O mg − Chl), and the lowest value was found for the F. pseudovina (0.54 g H 2 O mg − Chl).
In order to evaluate the effect of light intensity and photoperiod on heading and to establish the reaction types of barley, a set of barley germplasm of various geographical origin and growth habit was examined in a series of controlled growth chamber experiments combining two levels of light intensity with long and short photoperiod regimes. Low light intensity contributed only a limited portion to the total variance of heading and this originated to a large extent from the genotype × light intensity interaction for both photoperiods. Under the long photoperiod regime the effect of low light intensity was only apparent in a significant delay in heading. Under a short photoperiod the type of sensitivity depended on the growth habit. Low light intensity hastened plant development in 15% of the spring barley varieties, while the flowering of 44% of the winter barley varieties was significantly delayed. Establishing the reaction types for photoperiod and low light intensity in this range of barley germplasm made it possible to identify the typical reaction types of the two growth-habit groups. In addition, it also became possible to identify genotypes with contrasting or unusual combinations of these traits.
Abstract
Thermal stability of vegetative cells of Listeria monocytogenes, Escherichia coli and Lactobacillus plantarum was studied by counting viable fractions and determining DSC curves of their suspensions. DSC curves in the 5–99°C range showed a series of endothermic transitions between 50 and 60°C, where the heat destruction of cells occurred. Heat denaturation of DNA required a higher temperature than cell killing. Thermal death was strongly influenced by the pH, composition and NaCl content of the suspending buffer. A mathematical model developed by us enabled comparison of DSC peak temperatures and temperatures required for loss of viability.
In order to analyse the effects of temperature (9–22 °C) and light intensity (170–576 μmol m −2 s −1 ) on plant development two barley varieties with contrasting seasonal growth habits were included in a series of experiments consisting of controlled environment tests. The effect of constant (18 °C) and daily fluctuating (18/16 °C) temperature with a long photoperiod was also examined in a set of barley varieties including winter, facultative and spring barleys. Dicktoo with facultative growth habit was more sensitive to unfavourable conditions than Kompolti korai with winter growth habit; the flowering of Dicktoo was significantly delayed by sub-and supra-optimal temperatures and low light intensity accompanied by higher or fluctuating temperatures. The optimal temperature at flowering was also significantly lower for Dicktoo than for Kompolti korai (16.0 °C vs. 21.0 °C, respectively). Plant development was the fastest when there was no fluctuating environmental factor in the growing conditions and was significantly delayed with application of photo cycle. The addition of thermo cycle to photo cycle had an even stronger delaying effect. Facultative barleys were the most sensitive, followed by winter barleys, while spring barleys the least sensitive to the introduction of thermo cycle.
A barley mapping population consisting of 96 doubled haploid lines of anther culture origin was developed from the varieties Dicktoo and Kompolti Korai, which represent diverse types with respect to geographical origin and ecological adaptation. Several molecular marker techniques were used in mapping: among the markers with known chromosome location, RFLP, STS and SSR markers were applied to identify linkage groups and for comparative mapping, while RAPD and AFLP markers, which have random binding but provide useful information on polymorphism, were employed to fill in the linkage groups with markers. A total of 496 markers were tested in the DH population, 246 of which were included in the linkage map after eliminating markers that were completely linked with each other. The ratio of markers with known chromosome location to random markers in the 1107 cM map was one to three, and the mean recombination distance between the markers was 4.5 cM. Application of various marker methods and the effect of the population structure on the development of marker linkage maps are discussed.
