3828 research outputs found
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New data on the distribution of aquatic beetles in Serbia
No full textNew distributional data on 43 aquatic beetle species of Serbia from 17 sampling sites, mainly for Vojvodina (the part of Pannonian Plain) are provided. The field research was carried out in 2013 2023 (one decade). The rarity of findings particularly expressed in small lowland streams, such as those for Vojvodina revealed some aquatic beetle species are tolerant to water pollution. The study's main goal is to contribute to aquatic beetle taxa distribution in Serbia since the aquatic
beetle fauna of Serbia is poorly explored in general. Further research should focus on habitat preference of aquatic beetle species and better conservation of small aquatic habitats
Advanced thermodynamic approach to adsorption of charged adsorbates from aqueous electrolyte solutions
No full textThis study present estimation of the thermodynamic parameters and the influence of ionic activity coefficient on the thermodynamic equilibrium constant of adsorption of phosphates on fly ash. The adsorption was conducted over a wide range of initial phosphate concentrations at different pH values pH = (3; 7; 10). The adsorption results were treated using the Langmuir, Freundlich and Sips adsorption isotherms, which provide information about the maximum adsorption capacity. The Langmuir and Sips isotherms were a satisfactory fit to the adsorption data, especially at pH=3, with an acceptable regression coefficient over the entire concentration range, Langmuir (r2 =0.9737) and Sips (r2 = 0.9969). The estimated maximum phosphate sorption capacity of fly ash was 6.21±0.68 (mmolg-1) according to Langmuir and 4.190.16 (mmolg-1) according to the Sips model, at pH = 3.0. However, there is no data in the published literature for estimating the thermodynamic parameters of the phosphate adsorption process using thermodynamic models for activity coefficients. Novel approach of this paper was determination of the thermodynamic equilibrium constant and Gibbs free energy, using the Pitzer ion-interaction model to predict the nature of adsorption. The Pitzer-ion interaction model was used for the mixed ionic systems, taking into consideration the effect of other present ions besides phosphates in the equilibrium solution resulting from fly ash desorption. The procedure for comprehensive estimation of the ion activity coefficient at maximum adsorption capacity and the dimensionless thermodynamic equilibrium constant using Langmuir's and Sips’s constants was presented. The calculated value of the phosphate activity coefficient in the equilibrium solution was = 0.7003±0.0027 and the converted molar activity coefficient was = 0.6903±0.0027. The estimated values of Gibbs free energy were: ΔGL = – 6.788±0.521 kJ·mol-1 based on Langmuir equilibrium constant and ΔGa = –7.707±0.527 kJ·mol-1 based on activity and thermodynamic equilibrium constant. According to Sips model, the adsorption process is even more spontaneous, with the Gibbs free energy calculated using the phosphate activity coefficient and the thermodynamic equilibrium constant, ΔGa = – 9.707± 0.617 kJ·mol-1. Consideration of the ionic activity coefficient is particularly important for large, charged adsorbates at higher concentrations, as the absolute difference in free energy for adsorption is app. 12%. The scientific contribution is reflected in obtaining the necessary and more accurate information for the improvement of adsorption processes and possibly for the upgrading of fly ash in overall wastewater treatment technology
Enhanced stability of encapsulated lemongrass essential oil in chitosan-gelatin and pectin-gelatin biopolymer matrices containing ZnO nanoparticles
No full textThe use of essential oils is widespread in various fields such as pharmacy, pest control, and active packaging. However, their instability and short-term effects require methods to enhance their durability and effectiveness. Encapsulation in biopolymer matrices appears to be a promising approach due to the environmental safety and cost-effectiveness of such formulations. In this study, different oil-in-water emulsions were prepared by mixing chitosan-gelatin (C-G) or pectin-gelatin (P-G) solutions with lemongrass essential oil (LG). ZnO NPs were used as an additional active component. Encapsulation in biopolymer matrices resulted in stable emulsions with a significantly slower release of LG, and ZnO NPs further suppressed LG release, particularly in the P-G emulsion. They also contributed to the stability of the emulsions and a decrease in the average droplet size of LG. Furthermore, the presence of LG and ZnO NPs improved the smoothness of the films prepared from the emulsions and dispersions using the casting technique. SEM/EDS analysis confirmed the homogeneous distribution of ZnO NPs in both C-G and P-G films. By adjusting the type and content of the biopolymers and NPs, such emulsions could be effectively utilized in various applications where controlled release of active components is required
The response of the antioxidant system of cabbage (Brassica oleracea var. capitata L.) to infection with Xanthomonas campestris pv. campestris in combination with drought stress
No full textThe aim of this research was to investigate distinct effects of Xanthomonas campestris pv. campestris
(Xcc) and drought stress (D) and their combined effects (Xcc + D) on the activity of peroxidase
(POD) and the phenolic composition in cabbage leaves (autochthonous cultivar Futoški).
This pathogen causes black rot, severely affecting Brassicaceae cultivation, and in combination
with drought, it leads to significant cabbage yield losses. The combined stress resulted in maximum
stomatal closure, almost seven times higher compared to the control and 40% more than
in drought-stressed plants. On the contrary, the photosynthesis efficiency remained unchanged.
The highest accumulation of epidermal flavonoids was observed in Xcc + D plants, whereas the
chlorophyll content remained stable, nitrogen balance index (NBI) decreased by 20% compared
to the control and drought-stressed plants. The highest POD activity was induced by drought
alone, while combined stress reduced POD activity by almost 50%. In this experiment, the optical
fiber fluorescence measurements were performed directly on the surface of the investigated
plant leaves (excitation and emission wavelengths of 375 nm and 400-800 nm). It was found that
the intensity of the fluorescence spectra with emission maxima at 457 and 520 nm was higher in
the Xcc-infected leaves than in the healthy and drought-stressed leaves. These results showed an
increase in emission intensity in the spectral region corresponding to phenolics, suggesting that
the accumulation of phenolic compounds may be a plant response to the pathogen infection
Risk analysis of investing in greenhouse vegetable production-Abstract
No full textThis research aimed to investigate the risk analysis of investing in greenhouse vegetable
production, for the three most commonly cultivated species (tomato, cucumber, and pepper) in
the region of Bijeljina (Bosnia and Herzegovina). Data were collected from 35 family farms
using a face-to-face questionnaire (structure of production, type and area of protected
environment, and method of production with inputs and outputs). Results showed positive
financial results highlighting the tomato production to be more adaptable to changes in the yield,
variable and total cost considering the threshold of the economy obtained by the break-even
analysis. By using the Monte Carlo method, we analyzed the risk of the investment in the
covered systems with an equal share of tomato and cucumber in production under the following
assumptions: an investment in a protected area without additional heating of 4,000 m2, financed
with credit from a bank with an interest rate of 4% per year, while incomes and expenses arise at
the end of the year. During the 10-year exploitation period, net cash flow was positive and the
net present value of the investment was 73,436.51 EUR, which indicates that the investment is
economically justified if the projected values of the net cash flow are achieved. According to the
Monte Carlo method, we found that the expected net present value of investments was 57,649.89
and with 90% certainty, it can be concluded that the net present value will be in the interval from
30,438.62 to 81,860.70 EUR
The influence of starter fertilizer and variety on the production characteristics of broccoli-Abstract
No full textBroccoli (Brassica oleracea var. italica) is a cabbage that has a very significant nutritional and
health effect in human nutrition. For this reason, this type of vegetable is produced more and
more, and growing technologies are constantly being improved. The research was aimed in this
direction, in which the influence of micro granular starting fertilizer (Super Start NP 10:35,
Elixir Zorka) on the production characteristics of four broccoli hybrids (Monaco, Covina, Batory
and Parthenon) was examined in the agro ecological conditions of Banat (Serbia). In both
research years (2021-2022), broccoli was planted at the beginning of July at a density of 28,800
plants/ha. Fertilizer was added to the soil along both sides of the transplanted plants at a distance
of about 10 cm from the roots. In addition to the control in which it was not applied, there were 5
more treatments with starting fertilizer doses of 15 to 35 kg/ha. The lowest values for the height
of the inflorescence were recorded in the Batory hybrid in the variant without starter fertilization
(11.62 cm), and the highest in the Parthenon hybrid in the variant with the highest dose of starter
fertilizer (15.58 cm). These differences at the level of hybrids, as well as all fertilization variants,
were statistically very significant. The same was true for the inflorescence width parameter. The
mass of the inflorescence was the lowest in the Batory hybrid (289.7-439.6 g), and the highest in
the Monaco hybrid (542.7-778.3 g). The lowest values were in all hybrids in the control variety,
and the differences gained statistical significance with the increase in the dose of fertilizer. The
hybrid Batory had the lowest yields (6.90-10.46 t/ha), and Monaco F1 the highest (12.92-18.53
t/ha). Fertilization had a statistically very significant effect on the yield of all broccoli hybrids
GENE POOL OF FOREST FRUIT TREES IN THE PROTECTED AREA OF THE NATURAL MONUMENT "KOŠUTNJAK FOREST" - THEN AND NOW
No full textThe Natural Monument “Košutnjak Forest” is a protected area on the territory of the city of Belgrade
(Serbia). It is located in the immediate vicinity of the city center and covers 265.26 ha of protected
area, of which 1.31% of the area is under the second degree of protection, and 98.69% is under the
third degree of protection. The Košutnjak area is home to a large number of different woody species,
making it exceptionally rich in biodiversity. Among the species that occur in this area, forest fruit trees
occupy a significant percentage, and their value is reflected in their significant ecological impact, but
also in their medicinal properties, importance for animal nutrition and landscape beautification.
Forest fruit trees are less and less present in natural habitats due to anthropogenic influence, biotic
factors, invasive species, and climate change which emphasize the need for their conservation. Within
this research, an overview of forest fruit trees in the area of the Natural Monument “Košutnjak
Forest” during 1952, 1972 and 2022 was presented. In this area, in the research that was conducted
in the period from 2019 to 2022, 18 species of forest fruit trees were recorded, 12 of which are native,
and five belong to the category of rare and endangered, relict or species at risk in the forest fund of
the Republic of Serbia, which indicates the importance and necessity for their conservation
Potential of carbon bio-sequestration by wheat phytoliths in Vojvodina
No full textCarbon dioxide (CO2) is the primary greenhouse gas linked to global warming, with annual emissions potentially doubling to 80 billion tons by 2050. One of the most promising terrestrial biogeochemical carbon (C) sequestration mechanisms is the occlusion of C within phytoliths
(PhytOC). Phytoliths (SiO2 × nH2O), deposited beneath the cuticle, in the cell wall and lumen, are
highly resistant to decomposition and can remain unchanged in the soil for several thousand
years. To evaluate the potential of wheat for CO2 bio-sequestration, we conducted a filed survey in
Vojvodina, the main wheat-producing area in Serbia, accounting for 55% of the total wheat pro-
duction. We collected straw samples of different wheat cultivars alongside soil samples (plough depth) from 25 locations in Vojvodina. PhytOC concentration in the soil samples varied from 50 to
260 mg kg-1. Within the representative soil profile (0-120 cm), the PhytOC concentration was low-
est at a depth of 20-40 cm (average 160 mg kg-1) and highest at a depth of 40-60 cm (average 230 mg kg-1). PhytOC concentration in the straw samples ranged from 40 mg kg-1 (cultivar Pahulja) to 860 mg kg-1 (cultivar Sofru), showing great genotypical variation. Three-year crop rotation (wheat-maize-soybean) increased soil PhytOC concentration 1.4 times compared to wheat monoculture. The average amount of bio-sequestered CO2 in Vojvodina’s soils at plough depth is estimated to be 334 kg CO2 ha-1. Furthermore, wheat straw annually sequesters 15 kg CO2 ha-1 y-1, corresponding to about 5,500 tons of CO2 in the total Vojvodina’s wheat fields
Low phosphorus conditions promote mobilization of silicon in the grapevine rhizosphere
No full textDespite extensive research on silicon (Si) uptake and the cloning and characterization of Si
transporters in various crop species, including grapevine, data on Si mobilization in the rhizosphere
remains scarce, particularly for grapevines grown under field conditions. Our previous research
demonstrated that grapevine roots efficiently utilize phosphorus (P) by releasing carboxylates,
primarily citrate, which mobilize P from the rhizosphere. A field experiment was conducted
in a 12-year-old vineyard (cv. Chardonnay grafted on 5BB rootstock) in Toplica vine region, under
extremely low P conditions (Olsen P < 3 mg kg-1). The rhizotrons (80 cm depth) were installed in
the experimental vineyard to provide easy access to new, intact roots. Treatments included: control
vines (–P/–Si), P-fertilized vines (+P/–Si), and Si-fertilized vines (–P/+Si). Samples of rhizosphere
soil, root exudates collected from root types, and vine tissues (roots and leaves) were collected
at different growth stages according to the Eichhorn-Lorentz (E-L) system: flowering (E-L stage
23), pea-size berries (E-L stage 31), and veraison (E-L stage 35). The most intensive root release
of carboxylates, particularly citrate, was recorded at the flowering stage. Exudation of citrate by
grapevine roots was significantly higher in –P plants. Consequently, –P plants accumulated more
Si compared to P-fertilized plants, with Si accumulation levels comparable to Si-fertilized vines.
By contrast, P supply decreased both the rhizosphere concentration of available Si and leaf Si
concentration. In conclusion, low P-induced exudation of organic anions also mobilizes Si in the
rhizosphere, leading to higher Si accumulation in grapevine leaves
In Vitro Anthelmintic Potential of Selected Essential Oils against Gastrointestinal Nematodes of Sheep
No full textGastrointestinal nematodes (GINs) represent major obstacle to modern sheep farming, where the exclusive use of commercial anthelmintics is no longer a sustainable option due to the development of resistance in nematodes and the problem of drug residues in animal products and the environment. The aim of this study was to investigate the in vitro phytotherapeutic properties of seven essential oils (EOs) against GINs in sheep. Their chemical composition was determined by gas chromatography-mass spectrometry (GC-MS) analysis. The anthelmintic potential was evaluated using the egg hatch test performed at eight concentrations for each oil (50, 12.5, 3.125, 0.781, 0.195, 0.049, 0.025 and 0.0125 mg/mL). Additionally, a coproculture examination was performed to identify the GIN genera present in the tested fecal samples. The tested EOs showed a dose-dependent (R2 close to 1) ovicidal activity with basil - Ocimum basilicum L. (23.3-93.3%, IC50=0.08 mg/mL), spearmint - Mentha spicata L. (13.0-92.7%, IC50=0.07 mg/mL) and hyssop - Hyssopus officinalis L. (42.7-91.3%, IC50=0.19 mg/mL) being the most effective. The high activity of these oils could be attributed to the high content of the monoterpene alcohol linalool (O. basilicum) and the terpenoid ketones carvone (M. spicata) and pinocamphone (H. officinalis). Four genera of sheep GINs were identified on coproculture examination, i.e. Haemonchus 43%, Trichostrongylus 35%, Teladorsagia 17% and Chabertia 5%. The obtained results suggest that EOs of basil, spearmint and hyssop could represent a valuable alternative in the control of GINs in sheep, which could help to reduce the use of chemical drugs. Future field trials should be performed to confirm these findings