Abiotic stress is responsible for a significant reduction in crop plant productivity worldwide. Ultraviolet (UV) radiation is a natural component of sunlight and a permanent environmental stimulus. This study investigated the distinct responses of young wheat and einkorn plants to excessive UV-B radiation (180 min at λ_max 312 nm) following foliar pretreatment with 1 µM synthetic cytokinin 4PU-30. Results demonstrated that UV radiation significantly amplified hydrogen peroxide levels in both wheat and einkorn, with einkorn exhibiting a more pronounced increase compared to wheat. This elevation indicated the induction of oxidative stress by UV radiation in the two genotypes. Intensified antioxidant enzyme activities and the increased accumulation of typical stress markers and non-enzyme protectants were evidenced. Transcriptional activity of genes encoding the key antioxidant enzymes POX, GST, CAT, and SOD was also investigated to shed some light on their genetic regulation in both wheat and einkorn seedlings. Our results suggested a role for POX1 and POX7 genes in the UV-B tolerance of the two wheat species as well as a cytokinin-stimulated UV-B stress response in einkorn involving the upregulation of the tau subfamily gene GSTU6. Based on all our findings, it could be concluded that 4PU-30 had the potential of alleviating oxidative stress by attenuating the symptoms of superfluous UV-B illumination in the two examined plant species.

The territorial distribution of landslides along the Northern Bulgarian Black Sea coast has been evaluated by analyzing the results of field surveys for 2018 and 2019 based on geological surveys and processing of interferometric images from synthesized aperture radars (SAR). A local image archive of Sentinel-1A / B was created for the period 2015 - 2019 for this region and interferograms were produced every 4 months, 8 months, 1 year and in case of registering an event, led to the activation of landslide processes. A raster map of the concentration of deformations of the Earth's crust was created based on data from the obtained interferograms. Areas with active landslide movements along the Northern Bulgarian Black Sea coast have been identified for monitoring with the Global Navigation Satellite Systems (GNSS). A geodynamic network of 30 points covering the landslide circus ”Dalgiya Yar” and landslide “Thracian Cliffs“ was established and the first measurement cycle was carried out.

In this paper are presented the results from the investigations of the active landslide, located in front of the Thracian Cliffs golf club (Northern Bulgarian Black Sea Coast) for the period 2019–2021. Extensive research by means of in-situ and remote sensing has been carried out on the latest landslide activations. As part of the study, a control GNSS geodynamic network was established. This network was used as benchmark for the results obtained from satellite SAR data processing and UAV surveys targeted at monitoring the modern landslide developments.

Impact on the process of landslide origin and activation is result of many factors both endogenous and exogenous. The purpose of this study is to provide possibility for analysis and assessment of the geo-processes in the “Dalgia yar” landslide located at Northern Black Sea coast of Bulgaria in order to prevent risks and disasters of natural and anthropogenic origin. An important stage was to seamlessly include data from different sources such as geodetic measurements, satellite SAR (Synthetic-aperture radar) data as well as geological and geophysical data. The established geodatabase structures the collected information on dangerous geo-processes in the mentioned area and introduces them into the GIS (Geographic information system) environment. Its purpose is to facilitate the analysis of the available geological data for this landslide and to integrate them with results of measurements from regular monitoring. Interferometric images (IFIs), data from permanent GNSS (Global Navigation Satellite Systems) stations and from local geodynamic GNSS network, geological, seismic and geophysical data, updated geological maps and maps of the risk of landslide processes are included in the database. The IFIs have been produced using well established procedure for processing large number of Sentinel-1 SAR data of the purposely created local archive. Other key element used to improve the final results of SAR data processing and important part of the geodatabase is the precise Digital Elevation Model (DEM), which is much better in terms of horizontal and vertical resolutions than the open accessed ones (SRTM). The coordinates and velocities of the GNSS points are obtained from adjustment and analysis of two epoch measurements of the geodynamic control network of landslides “Dalgia yar”. Since the area has complex geological structure, small scale maps reflecting the geological and geophysical hazards are integral part of the geodatabase. Having all this information the analysis concerning the ongoing geodynamical processes in the study area is significantly improved and more reliable information is produced for better regional planning by the local authorities and residents.

The landslides are one of the well-known natural hazards occurring on the North East Black Sea coast of Bulgaria. The previous researches that take into account the geological and meteorological peculiarities of this region confirmed that the geomorphological conditions in this region are extremely favorable for landslide formation. Two are the main drivers that are being responsible for activation of the landslide processes in the area investigated. The first one is the sea erosion and the other is the increasing groundwater level. The influence of those is highly aggravated by the construction activities that took place in the last decades and the lack of sewerage networks. Those findings are based on information provided by the national authority responsible for monitoring and filing the landslides in Bulgaria. This was the motivation for developing and implementing reliable and accurate method for operational monitoring of the landslide processes in the said area. For development of such method data from SAR instruments were used. In this specific study data from Sentinel-1 SAR mission were processed by the freely provided by ESA SNAP software. Final results are interferometric images (IFIs) providing information about the ground movements. In this paper we present results reflecting the subsidence in the area of a landslide located some 20km north of the Albena resort. In the last decade two events have caused damages to the infrastructure in the area - one occurred in January 2015 which was attributed to the heavy rains the previous summer and the other took place in mid of August 2018. Both have been studied by processing SAR data for the periods mentioned. The results obtained are considered reliable since they have been reaffirmed by geodetic surveys and other terrain measurements. The outcomes of this research will contribute to better understanding the ongoing slow movements of the Earth’s crust, and for forecasting and early warning of geological hazards.