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Red-Light Transmittance Changes in Variegated Pelargonium zonale—Diurnal Variation in Chloroplast Movement and Photosystem II Efficiency
Get PDFChloroplast movement rapidly ameliorates the effects of suboptimal light intensity by accumulating along the periclinal cell walls, as well as the effects of excess light by shifting to the anticlinal cell walls. These acclimation responses are triggered by phototropins located at the plasma membrane and chloroplast envelope. Here, we used a recently developed non-invasive system sensitive to very small changes in red light leaf transmittance to perform long-term continuous measurements of dark–light transitions. As a model system, we used variegated Pelargonium zonale leaves containing green sectors (GS) with fully developed chloroplasts and achlorophyllous, white sectors (WS) with undifferentiated plastids, and higher phototropin expression levels. We observed biphasic changes in the red-light transmittance and oscillations triggered by medium intensities of white light, described by a transient peak preceded by a constant decrease in transmittance level. A slight change in red-light transmittance was recorded even in WS. Furthermore, the chloroplast position at lower light intensities affected the rapid light curves, while high light intensity decreased saturated electron transport, maximum quantum efficiency of photosystem II, and increased non-photochemical quenching of chlorophyll fluorescence and epidermal flavonoids. Our results extend the knowledge of light-dependent chloroplast movements and thus contribute to a better understanding of their role in regulating photosynthesis under fluctuating light conditions
The Impact of Soil Microplastic on Insect Diversity and Plastic Decomposition by Insects
Get PDFPlastic has been recognized as one of the leading pollutants of all ecosystems. This question has been rarely raised in Serbia, although there is a significant problem with the disposal of communal and agricultural waste. Many wild landfills have been created in past decades in forests near the plasticulture practicing areas and rivers. Plastic materials are degraded by the influence of UV light and various environmental factors, creating smaller particles called microplastics, which are recognized as significantly dangerous to ecosystems. Alluvial planes have been the most endangered due to the horizontal and vertical fluvial activities of the nearby rivers. The influence of soil microplastics on insect communities has not been widely considered and that is why the project EMIPLAST-SoS has been created to investigate insect communities in polluted and unpolluted alluvial soils in Serbia. We compare them in forest and agricultural ecosystems on similar alluvial soils in three locations near three largest rivers in Serbia. Preliminary results from one-season sampling are considered. During the project the influence of the different seasons effects will be investigated. Additionally, we have investigated the rate of plastic decomposition by five insect species in lab conditions (Plodia interpunctella Hubner, Tenebrio molitor L., Zophobas morio Fabr., Achroia grisella Fabr. and Galleria mellonela L.). G. mellonela expressed the highest and the most diverse decomposition of different plastic sources like plastic bags, sponges and styrofoam. The analyses of the obtained plastic residues are still underway
Impact of plastic pollution on the quality of arable soils in the Sava and Danube river valleys (Serbia)
Get PDFPlastic pollution is fast becoming a serious global environmental problem with the increase in plastic waste over recent decades. Plastic pollutants in the soil environment have an impact on the cycling of organic matter, global СО2 production, crop production, and soil properties. Crop production in plastic greenhouses is one of the serious sources of plastic pollution in the environment all over the world and particularly in Serbia. One of the
first investigations of plastic and microplastic materials in the soil on the territory of Serbia is currently underway and is being carried out within the project „Evaluation of the Microplastic in the Soils of Serbia – EMIPLAST – SoS“ funded by the Science Fund of the Republic of Serbia. The aim of the research was to reveal the impact of the presence of plastic materials on soil’s main chemical, physical and biological properties. Soil sampling was carried out in 2022 from two depths (0–15 cm and 15–30 cm), side by side from the plastic greenhouse and non-greenhouse agricultural production as a control in the first project year. The research sites are located on the alluvial plains of the two largest rivers in Serbia, the Danube and the Sava. The following chemical parameters were determined on all samples: electrical conductivity, pH, CEC, total C, as well as nutritional status of the soil (N, P2O5, K2O, Cu, Zn, Mn and CaCO3). Concentrations of some microelements were also analyzed. Physical parameters determined were: particle size distribution, volumetric mass, specific mass and porosity. Microbial respiration, which serves as an indicator of enzymatic microbial activity in the soil, was measured by the alkaline trap method from surface soil
Wavelets and stochastic theory: Past and future
No full textIn the paper, authors report on the interdisciplinary and extremely complex link between wavelets and stochastic processes. An insight into the history of wavelets has been provided presenting the fundamental conception of wavelets, as well as wavelet theory that emerged from stochastic processes. The multiresolution analysis corresponds to the Kolmogorov system which is a regular stationary stochastic process. It presents a significant link to the measurement problem in terms of positional notation which the wavelet domain hidden Markov model should be derived from. The optimal representation arises to be an issue requiring further elaboration extended to the general measurement and wavelet frames
Identification of the field elm gene pool in the protected natural area KOSMAJ (Serbia) as a basis for its conservation and sustainable use
Get PDFThe field elm (Ulmus minor Mill.) is an autochthonous tree species in Serbia that occurs as a
secondary species in oak forests. In the forest fund of Serbia, this species is rare/endangered
due to the genetic erosion and disappearance of elms from natural populations, mainly as a
result of Dutch elm disease. In the protected natural area „Kosmaj“ the field elm was identified
as one of the target species from the aspect of conservation. This research aimed to identify and
assess the state of available field elm genepool in the protected natural area „Kosmaj“, as a
basis for its conservation and sustainable use. By terrain reconnaissance a field elm gene pool
was identified, representing almost 100 trees: 47 individuals and 8 groups of trees, on an area of
652.99 ha. All trees were georeferenced and mapped. The average height of the trees is 10.34
m, the diameter at breast height is 15.68 cm, the perimeter is 51.09 cm, while the average
crown span is 3.95 m. Dry tops or dry side branches of trees, absence of yield for a long period,
and weak natural rejuvenation were recorded. The selected trees will be included
inconservation units, which were proposed to conserve the available gene pool in situ. To
conserve the available genepool ex situ, the cuttings from selected mother trees were collected
and the clonal test was established in the greenhouse of the Faculty of Forestry, University of
Belgrade. This clonal test could be a basis for the establishment of a field gene bank in the
future. It is planned to determine the variability of the selected trees, using morphological and
molecular markers. The initiated activities should contribute to the conservation and
sustainable use of the field elm gene pool in the protected natural area „Kosmaj“ and further
breeding of the species
Diversity of true truffles (Tuber spp.) in European biodiversity hotspots, the role in soil bioremediation
Get PDFAbstract book was not published as a official publication and can be viewed on the site of the congress:
https://gsb2023.org
Namotani kondenzator realizovan u Fused Fabricated Filament tehnologiji
Get PDFIdeja za razvoj ovih 3D štampanih kondenzatora y FFF (Fused Fabricated Filament) tehnologiji je proistekla iz istraživanja u oblasti 3D štampe. Provodni ABS kompozitni materijal je korišćen za proizvodnju 3D štampanih elektroda namotanog kondenzatora primenom komercijalno dostupnog 3D štampača (nano3Dprint A2200). Kondenzator sadrži Arhimedove spiralne elektrode čije su dimenzije: unutrašnji prečnik 10mm , debljina elektroda 0,6 mm, visina 10 mm
Tunnel Junction Sensing of TATP Explosive at the Single-Molecule Level
Get PDFTriacetone triperoxide (TATP) is a homemade, potent explosive and, unfortunately, is used in many terrorist attacks. It is hard to detect, and present techniques for its sensing do not offer portability. Fortunately, TATP is volatile, and gas-sensing-based devices for TATP detection would provide a higher level of safety. Here, we explore the possibility of single molecule TATP detection in the air by tunneling current measurement in the N-terminated carbon-based nanogaps, at the DFT+NEGF level of theory. We found TATP averaged current amplitude of tens nano amperes, with a discrimination ratio with respect to prevalent indoor volatile organic compounds (VOC) of a few orders of magnitude. That high tunneling current is due to specific TATP HOMO contributions to electronic transport. The transport facilitates the strong, in-gap electrical field generated by N-C polar bonds from electrode ends and TATP electrode hybridization, spurred by oxygen atoms from a probed molecule
Comparative evaluation of liver enzymes activities in Vimba bream and Common nase living under the same ecotoxicological conditions
Get PDFThe present study was carried out to investigate the differences in some enzymatic components of liver in vimba bream (Vimba vimba) and common nase (Chondrostoma nasus). For this purpose, 33 healthy vimba bream and 20 common nase were collected from commercial catches on the Danube River, near Belgrade (1172-1173 rkm), in 2016. The blood samples were taken and after separation of serum, the values of Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT) enzymes activities were measured. Based on obtained results, the values of AST and ALT enzymes activities were slightly lower in the common nase compared to vimba bream, which is a possible indicator of better health and physiological status, and greater resistance to environmental pollutants present in the habitat. This difference was, however, not statistically confirmed. Considering that the selected fish were captured by the same method, having a similar ecology, living in similar habitats and under similar ecotoxicological conditions, it is not surprising that the differences in the activity of the measured liver enzymes were minimal. Since common nase is important bioindicator species, similar results could indicate that vimba bream could be considered as replacement species for this types of research, if future studies indicate the decline or endangerment of common nase populations
Investigation of silica-lignin interaction. Application of AFM and fluorescence techniques
Get PDFIn this study, we investigated, in an in vitro system, the interaction of SiO2 (as a complex with NH4OH) with the peroxidase-catalyzed polymerization of lignin monomer into lignin model compound DHP, imitating conditions of the last step of lignin formation in the cell walls. The structure of obtained polymer was monitored using fluorescent spectroscopy and AFM 30 minutes after the start of synthesis. We studied effect of two different Si concentrations, 0.6 mM and 6 mM. Analysis of the DHP fluorescent spectra, and the application of mathematical decomposition clearly shows that structure of lignin model compound depends on Si concentration in the reaction mixture. The amount of Si affects the distribution of electrons in the DHP polymer. When silicon is present at a concentration of 6 mM, the position of the longest-wavelength APD band shifts towards shorter wavelengths compared to the position of the APD band for 0.6 mM Si. This indicates that during polymer synthesis, higher concentration of silicon may inhibit the formation of pi-electronic structures, which are responsible for electron delocalization. AFM images also show differences in the size and regularity of DHP globules