Materials, Methods & Technologies ISSN 1314-7269, Volume 10, 2016 Journal of International Scientific Publications www.scientific-publications.net Page 175 VOLUME CHANGES OF OVERGROUND PARTS OF THE PLANTS AS AN EXPRESSION OF WATER STRESS Viliam Bárek 1 , Ján Horák 2 , Alan Klimaj 1 1 Department of Landscape Engineering, Slovak University of Agriculture, Nitra, Slovakia 2 Department of Landscape Engineering and Hydrology, Slovak University of Agriculture, Nitra, Slovakia Abstract The future of the primary agricultural production relies on the responses to enhanced changes of climatic factors associated with the global warming and greenhouse effect by releasing the new genotypes, more tolerant to drought, extreme temperatures, low nutrient content, changes in population density and pathogenicity of pests and diseases. The co-occurring phenomena, such as aridization or fluctuation of precipitation in the particular area would be probably present even in the Slovak conditions. It appears that not only the systematic change of the long-term mean temperature and precipitation compared to long-time average level, but also the diurnal and seasonal variability and frequency of weather fluctuations or extreme days would play an important role. Therefore, it is necessary to draw attention in advance to possible consequences and possibilities to optimize the production process. There is a need of specification of effects of weather fluctuations on the regulation of growth-production factors as well as the importance of a special gene expression needed to crop tolerance or resistance or running the protection mechanisms. Our experiment showed that introduction of multi-parametric approaches is useful for a deeper comprehension of interactions in the system soil - plant - atmosphere, as well as for manipulation of these interactions in all their components. Thus, it will lead to a more dynamic understanding of this interaction and to the production of new genotype constructs. Key words: dendrometer, precipitation, above-average high temperatures, diameter changes 1. INTRODUCTION Prognoses of the global climate change predict an increase of the greenhouse effect, thus increasing the importance of topics, such as desertification of regions, aridization, increasing of temperature of the aboveground atmospheric layer (and thus temperature of plant environment). These factors would increase the plant stress occurrences, but also the requests to ensure sufficient water regime of crop plants. Water in plants fulfils important functions, as it represents the environment for running of all metabolic processes. It allows transport of mineral nutrients and products of photosynthesis. The lack of water inhibits the growth, leaf expansions, CO2 assimilation, source-sink relations in terms of assimilates movement, biomass production as well as the final crop yield (Brestič, Olšovská, 2001). The sufficient plant water supply is essential for realization of crop genetic potential. Therefore, in a global scale, greater attention is paid to increasing of functional properties of crop plants and to their tolerance to drought and high temperature, as well as optimization of water regime by irrigations. For the management of the agriculture soils soil moisture regime it has to be emphasized the specific property of Bioclimatology of agricultural plants and animals. Every ecosystem, but also any plant or animal species in the environment of implementing such a way that is in their genetic property and information about how the most successful survival in these climatic conditions, which not only adapts to average climate values, but also to change them. The adjustment process is the more conflicting, which is climate change faster and bigger. To be able to anticipate the possible consequences of climate change, and then prepare effective adaptation, it is necessary to know reactions of the various climate-sensitive systems to the limits in the past on the one hand and try to monitor continuously and consistently change and the implications of changes to various systems on other hand side.