hydrogeologically closed Carpathian Basin
particular importance in the salinization/alkalization processes. In the
poorly-drained low-lying areas the capillary flow transports high amounts of
water soluble salts from the shallow, „stagnant” groundwater with high salt
concentration and unfavourable sodium-carbonate(bicarbonate) type ion
composition to the overlying soil horizons. Due to the strongly alkaline soil
solution, the Ca and Mg salts (mostly carbonates and bicarbonates) are not
soluble and Na
became absolutely predominant in the migrating soil
solution which leads to high ESP even at relatively low salt concentration.
saturation of heavy-textured soils with high amount of
expanding clay minerals results in unfavourable physical-hydrophysical
extreme moisture regime
of these soils, which are their
main ecological constrains and the limiting factors of their fertility,
productivity and agricultural utility. The simultaneous hazard of waterlogging
or overmoistening, and drought sensitivity in extensive lowland areas,
sometimes in the same places within a short period, necessitates a precise,
“double function” soil moisture control against their harmful
ecological/economical/social consequences. Most of the environmental constrains
(including salinity/alkalinity/sodicity) can be efficiently controlled:
prevented, eliminated, or - at least - moderated. But this needs permanent care
and proper actions: adequate soil and water conservation practices based on a
comprehensive soil/land degradation assessment. It includes continuous
registration of facts and changes (monitoring); exact and quantitative knowledge
on the existing soil processes, their influencing factors and mechanisms.
Due to their sessile life style plants have to cope with a variety of unfavourable environmental conditions. Extracellular stimuli are perceived by specific sensors and receptors and are transmitted within the cell by various signal transduction pathways to trigger appropriate responses. The mitogen-activated protein (MAP) kinase cascades are well-conserved signalling pathway modules found in all eukaryotes. Activated MAP kinases phosphorylate an array of substrate proteins. Phosphorylation results in altered substrate activities that mediate a wide range of responses, including changes in gene expression. The genome of the model plant Arabidopsis thaliana contains genes encoding 20 mitogen-activated protein kinases and 10 MAPK kinases. In plants MAP kinases play a central role in environmental stress signalling; however, our knowledge mainly comes from results on three MAP kinases and their immediate upstream activators. Further studies on additional members of the plant MAP kinase repertoire together with the identification of downstream substrates and connections to specific upstream signal receptors are required to elucidate their specific functions within environmental stress signalling networks. Understanding the mechanisms of specificity in signal flow is indispensable for engineering improved crops with modified MAP kinase signalling for agricultural purposes.
Soils represent a considerable part of the natural resources of Hungary. Consequently, rational land use and proper soil management - to guarantee normal soil functions - are important elements of sustainable (agricultural) development, having special importance both in the national economy and in environment protection. The main soil functions in the biosphere are as follows: -conditionally renewable natural resource; -reactor, transformer and integrator of the combined influences of other natural resources (solar -radiation, atmosphere, surface and subsurface waters, biological resources), site of “sphereinteractions”; -medium for biomass production, primary food-source of the biosphere; -storage of heat, water, plant nutrients and - in some special cases - wastes; -high capacity buffer medium, which may prevent or moderate the unfavourable consequences of various environmental stresses; -natural filter and detoxication system, which may protect the deeper geological formations and the subsurface waters from various pollutants; -significant gene reservoir, an important element of biodiversity; -conservator of natural and human heritages. Society has utilized these functions in different ways (rate, method, efficiency) throughout history, depending on the given natural conditions and socio-economic circumstances. In many cases the character of the particular functions has not been properly taken into consideration during the utilization of soil resources, and misguided management has resulted in their over-exploitation, in the decreasing efficiency of one or more soil functions, and - above a certain limit - in serious environmental deterioration. The scientifically based planning and implementation of sustainable land use and rational soil management to ensure desirable soil functions, without any undesirable environmental side-effects, require the efficient control of soil processes.
It is well-documented that harsh environmental conditions influence appetite and food choice. However, the experience of environmental harshness is complex and shaped by several underlying dimensions, notably threats to one's social support, economic prospects, and physical safety. Here, we examined the differential effects of these three dimensions of environmental harshness on desire for specific food items. We first showed 564 participants images of 30 food items. Next, they rated how much they desired each item. The participants were then randomly assigned to a condition where they read one of six scenario stories that described someone's current living conditions. Each scenario story emphasized one of the three dimensions (social support, economic prospects, physical safety), with two levels (safe, harsh). Following this, the participants once again rated how desirable each food item was. The results showed that exposure to cues of low social support and high physical threat reduce the desire to eat, whereas cues of economic harshness had little effect. Further analysis revealed a significant interaction between energy level of different foods and perceived threat to physical safety. These findings are important in helping to understand how current environmental conditions influence changes in appetite and desire for different kinds of food items.
Authors:E. Sapi, K. Gupta, K. Wawrzeniak, G. Gaur, J. Torres, K. Filush, A. Melillo, and B. Zelger
Lyme disease [ 22 ]. Biofilms are an aggregation of planktonic bacteria that attach on biotic and abiotic surfaces to form a three-dimensional architecture to withstand various environmentalstressors [ 23 ]. The presence of a protective surface matrix
Authors:T. Kovács, Z. Bihari, A. Hargitai, I. Mécs, and K. L. Kovács
The changes of cell surface hydrophilicity in Bacillus subtilis were analyzed in response to oxygen-limitation, heat shock, salt stress, pH-shock, phosphate- and carbon-limitation. Although cell surface hydrophilicity varied during growth phases, an increase of surface hydrophilicity was observed under several of these stress conditions. An observed drop in intracellular GTP and/or ATP may be an element of the signal transduction pathway leading to an increase in surface hydrophilicity in response to environmental stresses. Attachment of cells to soil particles under salt stress conditions is strongly influenced by the degS/degU two-component system, which thereby provides a mechanism for the bacteria to escape from the hostile environment.
Authors:M. Yukawa, K. Aoki, H. Iso, K. Kodama, H. Imaseki, and Y. Ishikawa
The balance of essential elements in organisms can be changed by environmental stresses. A small fresh water fish, the medaka,
was irradiated with X-rays (total dose: 17 Gy, which is not a lethal dose for this fish). Essential elements in the liver,
gall bladder, kidney, spleen, heart and brain of the fish were measured by the particle induced X-ray emission (PIXE) method
and compared with those of a control fish. Various changes in the elemental balance shift were observed. The PIXE method can
analyze many elements in a small sample simultaneously, and so the changes in elemental content induced by irradiation were
Environmental stress can lead to a reduction in developmental homeostasis, which could be reflected in increased variability of morphological traits. Fluctuating asymmetry (FA) is one possible manifestation of such a stress, and is often taken as a proxy for individual fitness. To test the usefulness of FA in morphological traits as an indicator of environmental quality, we studied the effect of urbanisation on FA in ground beetles (Carabidae) near a Danish city. First, we performed a critical examination whether morphological character traits suggested in the literature displayed true fluctuating asymmetry in three common predatory ground beetles, Carabus nemoralis, Nebria brevicollis and Pterostichus melanarius. Eight metrical (length of the second and third antennal segments, elytral length, length of the first tarsus segment, length of the first and second tibiae, length of the proximal and distal spines on the first femurs) and one meristic (the number of spines on the second tibiae) traits were examined. Most of them showed FA but not consistently. Females generally displayed a higher level of FA than males. Finally, we examined the changes in the level of FA in bilateral morphological traits along an urbanisation gradient (forest - suburban forest - forest fragments in urban park) to test whether environmental stress created by urbanisation is reflected in FA. Ground beetles common along a Danish urbanisation gradient did not seem to indicate differences in habitat quality by their level of FA.