Germination of four Central European Bolboschoenus species (B. yagara, B. koshewnikowii, B. maritimus and B. laticarpus) was studied. The need for stratification and the influence of temperature and water regime on seed germination were tested in the laboratory. Cold wet stratification in the laboratory as well aswater stratification in the field enhanced the germination of all species. Germination was facilitated by increasing stratification length, but differed between species. Field stratification in water improved the germination of all species compared to stratification in soil. Germination requirements of the four Bolboschoenus species, despite the broader ecological amplitude of B. laticarpus, were similar. The best germination occurred after four months of field stratification in cold water. All species germinated best in aerobic conditions when the day/night temperature fluctuations were high (30/10 °C). These conditions correspond to those occurring where the seedlings tend to establish themselves in the field: exposed pond bottoms or wet soil in field depressions.
The objective of this study is to make a conceptual and numerical model of the groundwater flow system which will improve the understanding of the groundwater cycle in the area of the Čenkov Valley, Slovakia. Extreme deficits of atmospheric precipitation and thereof resulting periods of low water flows and discharges could very negative impact the water management. Increasing water consumption in the future will be the most critical in strong and intensive dry periods. Almost every climatic zone could suffer from drought, although its features could considerably vary from region to region. The study is handling with creating, calibration and verification of numerical model of groundwater flow in the reparian alluvial aquifer of the Čenkov Valley in south-east part of the Danubian lowland for minimal anthropogenic disrupted natural conditions in the past and quasi-steady deficit water regime of the area. The conceptual model is based on data from earlier studies in the area complemented with data collected in the field. Results of model solutions are presented in the study - groundwater level, filtration velocity vectors, groundwater paths by particle tracking and water budget of study area. Created numerical model could be used for simulation of underground dam function, which belongs to the types of artificial recharge of reparian alluvial aquifer management, and also for creating prognostic scenarios concerning expected climatic changes. Additional future work may include adding a solute transport model to the flow model. and Cieľom predloženej štúdie je vytvorenie koncepčného a numerického modelu systému prúdenia podzemnej vody na území Čenkovskej nivy na Slovensku. Extrémne deficity atmosférických zrážok a z toho vyplývajúce obdobia nízkych vodných stavov a prietokov môžu vplývať na vodné hospodárstvo veľmi negatívne. Zvýšená spotreba vody bude v budúcnosti najkritickejšia práve počas drasticky suchých periód. Takmer každá klimatická zóna môže trpieť suchom, hoci jeho charakteristiky sa môžu od regiónu po región značne líšiť. Štúdia sa zaoberá tvorbou, kalibráciou a verifikáciou numerického modelu prúdenia podzemnej vody v pririečnom hydrogeologickom kolektore Čenkovskej nivy v juhovýchodnej časti Podunajskej roviny, za minimálne antropogénne narušených prírodných podmienok v minulosti a kvázi ustáleného deficitného vodného režimu územia. Koncepčný model je založený na údajoch z predošlých štúdií doplnených o údaje zhromaždené v teréne. V štúdii sú prezentované výsledky modelového riešenia - poloha hladiny podzemnej vody, vektory filtračnej rýchlosti, smery prúdenia podzemnej vody prostredníctvom trasovania pohybu častíc a vodná bilancia územia. Vytvorený numerický model môže byť využitý na simuláciu funkcie podzemnej priehrady, ktorá patrí medzi typy umelého nasycovania pririečneho aluviálneho kolektora a tiež pri tvorbe prognostických scenárov, zaoberajúcich sa klimatickými zmenami. Doplnková budúca štúdia sa môže venovať pripojeniu transportného modelu chemických látok k prezentovanému tokovému modelu.
In the order C. microphylla - C. intermedia - C. korshinskii, compensation irradiance, saturation irradiance, and optimum temperature for photosynthesis increased, net photosynthetic rate (PN) at low irradiance and low temperature decreased, optimum air humidity decreased, and PN at low air humidity increased. Daily cumulative value of PN increased while daily cumulative value of transpiration (E) decreased, and hence water use efficiency (WUE =PN/E) increased. Diurnal course of PN of C. microphylla was a double-peak curve, but the second peak in the curves of C. intermedia and C. korshinskii was not visible. These physiological characteristics are biological basis for the geographical distribution of these three Caragana species, and are in relation to water conditions of their habitats and distinctiveness in leaf hair of plant. and C. C. Ma ... [et al.].