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141.
142.
Vesna Poleksić Marko Stanković Zoran Marković Renata Relić Nada Lakić Zorka Dulić Božidar Rašković 《Aquaculture International》2014,22(1):289-298
The study was carried out to examine morphological and physiological effects of different levels of fat in compound extruded feed for carp. A 90 days experiment was performed in tanks with water flow 0.34 L min?1, stocked each with 29 specimens of carp, average weight 15.4 ± 4.2 g. The fish was fed 3 diets containing 38 % protein and 8, 12 or 16 % of fat (feed L8, L12, and L16, respectively). Body weight gain, specific growth rate, food conversion ratio, feed efficiency ratio, condition factor, liver and intestine histology and morphometry and some blood biochemical parameters were analysed. At the end of the experiment, a difference was established between the fish fed L8 feed compared to carp fed L12 and L16 feed for all growth parameters. For several other parameters, nuclear area of hepatocytes, nuclear/cytoplasm ratio, enterocytes height and intestinal folds’ length, a difference between carp fed feed L8 compared to feed L16 was found. The histological analysis revealed that normal structure of the liver and intestine prevailed, but changes were observed regardless of the diet type. In the hepatopancreas, more prominent changes were found around pancreatic tissue—particularly, increased number and size of adipocytes. Although blood biochemical parameters were within normal values, a difference between L8 and L16 diet-fed carp was found for plasma levels of triglycerides and total proteins. According to the results obtained in this study, the best results were achieved using a feed with 8 % fat. 相似文献
143.
Jasna Milanović Vesna Kajić Snježana Mihaljević 《European journal of plant pathology / European Foundation for Plant Pathology》2014,139(4):785-788
Viroids of the genus Pospiviroid are able to induce diseases in a wide range of host plants including important crop species. Although occasional disease outbreaks of Potato spindle tuber viroid (PSTVd) and closely related pospiviroids have been reported in potato and tomato, recent studies found an increase in number of latent infections in ornamental solanaceous species. In order to verify the presence of PSTVd and other pospiviroids in Croatia, a survey was conducted between 2009 and 2012. A total of 182 samples belonging to five ornamental species and two solanaceous crops were analyzed. Eight plants belonging to two different species (Solanum jasminodes and Lycianthes rantonnetii) were found infected by PSTVd and, in addition, one S. jasminoides plant infected by Tomato apical stunt viroid (TASVd). Viroid infection was confirmed by mechanical inoculation on tomato plants to observe symptom expression. Molecular characterization of the isolates was done and complete viroid sequences were submitted to the GenBank. This is the first evidence of the presence of PSTVd and TASVd and their variability in Croatia. 相似文献
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146.
Petr Hlavinka Miroslav Trnka Daniela Semerádová Martin Dubrovský Zdeněk Žalud Martin Možný 《Agricultural and Forest Meteorology》2009,149(3-4):431-442
The relationship between seasonal agricultural drought and detrended yields (within a period from 1961 to 2000) of selected crops was assessed in the conditions of the Czech Republic, which are to some extent representative of a wider area of Central Europe. Impact of water stress was analyzed using time series of yields for 8 crops (spring barley, winter wheat, grain maize, potato, winter rape, oats, winter rye and hay from permanent meadows) for 77 districts in the Czech Republic (average district area is 1025 km2). Relative version of Palmer’s Z-index (rZ-index or rZ-i) was used as a tool for quantification of agricultural drought. The monthly values of the rZ-index for each individual district were calculated as the spatial average (only for the grids of arable land). The study showed that severe droughts (e.g., in 1981 and 2000) are linked with significant reduction in yields of the main cereals and majority of other crops through the most drought prone regions. We found a statistically significant correlation (p ≤ 0.05) between the sum of the rZ-index for the main growing period of each crop and the yield departures of spring barley within 81% (winter wheat in 57%, maize in 48%, potato in 89%, oats in 79%, winter rye in 52%, rape in 39%, hay in 79%) of the analyzed districts. This study also defined the crop-specific thresholds under which a soil moisture deficit (expressed in terms of rZ-index) leads to severe impact at the district level. This can be expressed as the sum of the monthly rZ-index during the period of high crop sensitivity to drought; for spring barley it is ?5, winter wheat ?5, maize ?9, rape ?12, winter rye ?10, oat ?4, potato ?6 and for hay ?3. The length of the sensitive period is also crop-specific and includes the months that are important for the yield formation. The results show that yields of spring barley (and spring crops in general) are significantly more affected by seasonal water stress than yields of winter crops and hay from permanent meadows. The study proved that a severe drought spell during the sensitive period of vegetative season does have a quantifiable negative effect, even within more humid regions. These results demonstrate that, at least in some areas of the CR (and probably most of Central Europe), drought is one of the key causes of interannual yield variability. 相似文献
147.
Rimantė Zinkutė Ričardas Taraškevičius Margarita Jankauskaitė Žilvinas Stankevičius 《Journal of Soils and Sediments》2017,17(2):440-452
Purpose
The research is aimed at comparison of different enrichment factors (EFs) calculated for potentially harmful chemical elements (PHEs) basing on topsoil data from Klaip?da with geological differences between two areas, choice of the reference elements (REs), consideration of the expediency and efficiency of normalisation, the influence of PHE and RE background or upper threshold values on the estimated contamination level of 50 schoolyards and the arising problems, i.e. which PHE should be normalised.Materials and methods
Composite topsoil samples taken in 50 schoolyards and 28 football fields from 0 to 10-cm depth were air-dried, sieved to <1 mm, milled and analysed for total contents of major elements and As, Ba, Cr, Cu, Mn, Mo, Ni, Pb, Sn, U, V and Zn by energy-dispersive X-ray fluorescence and of Ag and Co by optical atomic emission spectrophotometry. Simple EFs in schoolyards were calculated normalising by concentration factor (CF) of Fe, while complex EFs normalising by weighted average of Al, K and Ti concentration factors (WACFs).Results and discussion
The variability of RE is shown with significant differences between sandy western and loamy eastern areas and lower differences between schoolyards and football fields. The highest effectiveness of normalisation, i.e. the number of sites where WACF > 1 or CF > 1, is when RE background values for schoolyards differentiated for each area are selected. The formulas for the ratio of different EFs demonstrate that (1) for Co, Ba, Mn, Mo, Pb and Cu, the upper threshold-type EFs exceed the background-type EFs; (2) there is the tendency to obtain lower EFs for the greater part of PHE when using differentiated background of PHE and RE. The problems of estimation of the background of some PHE and the expediency of their normalisation are discussed.Conclusions
The recommendations are (1) to explore the variability of RE in the urban territory and to find out if there are areas with significant differences in RE content, in this case try to estimate the differentiated background values of RE and PHE, because respective EFs are usually lower; (2) for more effective normalisation, to use background values of RE which correspond to the object of assessment; (3) not to use upper threshold-type EFs; (4) to be careful with interpretation of EFs for those PHEs which have significant negative correlation with RE.148.
Nenad Grba Dejan Krčmar Franz Neubauer Srđan Rončević Marijana Kragulj Isakovski Jelena Molnar Jazic Božo Dalmacija 《Journal of Soils and Sediments》2017,17(11):2610-2619
Purpose
The aim of this study was to obtain a complete picture of the geochemical character of the sediment in the eastern Posavina region, Serbia, an area which has thus far not been systematically investigated. Geological mapping and impact assessment were thus carried out for this area.Materials and methods
Sediments were sampled (from 0 to 0.5 m depth) in four locations in eastern Posavina between 2002 and 2014. Eight heavy metals (Ni, Zn, Cd, Cr, Cu, Pb, As and Hg) and a wide variety of organic parameters (16 EPA polycyclic aromatic hydrocarbons (PAHs), mineral oils, selected pesticides and polychlorinated biphenyls (PCBs)) were monitored. Metals were analysed by flame and graphite atomic absorption spectrometry, and gas chromatography with mass detection was used for the PAH analyses. The origins of the monitored substances were classified using geoaccumulation index (I geo), ecological risk index (RI) and principal component analysis (PCA/FA).Results and discussion
The sediments all contained higher heavy metals concentrations than the upper continental crust (UCC), suggesting dynamic natural and anthropogenic processes in this unique region. Significant variations (RSD values from 13 to 190) were observed for Cd (0.001–80.00 mg kg?1), Hg (0.01–5.40 mg kg?1), mineral oil (2.00–1851 mg kg?1) and the sum of 16 EPA PAHs (0.003–5.57 mg kg?1). The I geo index classified the pollution risk due to Cr as strong, Cd, Zn and Hg as moderate to strong and Ni as moderate. Based on PCA/FA analysis, the parameters were grouped somewhat differently, with anthropogenic activity found to be responsible for much of the Hg, Cd and Cr pollution present in the sediments.Conclusions
The analysis revealed eight heavy metals (Ni, Zn, Cd, Cr, Cu, Pb, As and Hg), the sum of 16 EPA PAHs and mineral oil as parameters of great interest for this unique region. These parameters must be the focus of future monitoring programs, in support of appropriate remediation techniques and/or dredging activities, which are required in order to comply with the new Serbian regulations and the relevant EU recommendations.149.
Evžen Stuchlík Peter Bitušík David W. Hardekopf Zuzana Hořická Marie Kahounová Jolana Tátosová Daniel Vondrák Kateřina Dočkalová 《Water, air, and soil pollution》2017,228(5):184
Alpine lakes of the Tatra Mountains were severely affected by acidification, with minimum recorded values of pH ～4.5 in the mid-1980s. Since the 1990s, a dramatic decrease in the deposition of acidifying compounds has led to a considerable reversal in lake water chemistry (to pH～5 in the most severely affected lakes). We studied changes of planktonic crustaceans and chironomid occurrence during the acidification period and the following period of recovery from acidification in three categories of 50 Tatra Mountain lakes (non-acidified, acidified and strongly acidified, according to their status at the beginning of the 1980s). In acidified and strongly acidified lakes, the planktonic crustaceans completely disappeared already by about 1976 except for a few individuals of ubiquitous species in littoral zone due to acidification-induced oligotrophication. In strongly acidified lakes, the original planktonic crustaceans disappeared and littoral species became more abundant already before 1976 due to acidification-induced eutrophication and aluminium toxicity. These processes were quickly reversed following the increase in lake water pH. Extinct species started to return to several acidified and strongly acidified lakes already in the beginning of 1990s. The process of recovery was delayed in many other lakes of the same categories, however, or it did not even start before 2008 despite the improved water chemistry and feeding resources (concentration of chlorophyll-a). Compared to planktonic crustaceans, the reaction of chironomids to acidification and recent recovery has been less pronounced. An analysis of sediment records showed that fluctuations in relative abundance of the dominant chironomid taxa and a decrease of their density occurred. In spite of the fact that chironomid fauna exhibited clear signs of recovery in the last two decades, the recovered assemblage does not exactly reflect the pre-acidification status in the lake. The occurrence and higher proportion of more thermophilous chironomid species in some alpine lakes of all categories could be correlated with increasing air temperature. The considerable effect of climatic factors may thus prevent the full re-establishment of the original status even when the acidification stress completely ceases. The delayed return of planktonic crustaceans to some recovered lakes could be a consequence of the short water residence time of these lakes. In addition, a shortening of the water residence time in recent decades, probably related to recent climate change, in interaction with the ecology of planktonic crustaceans, may possibly be causing further delays in their return. 相似文献
150.
During the monitoring of the health status of nurseries and plantations in Serbia, a decline in a 5‐year‐old Paulownia tomentosa plantation was recorded. Trees displayed symptoms of dieback, massive breaking at different positions, the appearance of decay and fungal fruitbodies at the stems. Using standard isolation methods, white colonies with cottony surfaces and regular growth were obtained from the decaying wood samples, and after the oxidation degree analysis, it was determined that these isolates belonged to Davidson's group 6, indicating white rot basidiomycetes. To identify the isolated fungus, the ITS region of one selected isolate was sequenced. Based on the morphological analysis of the obtained colonies, collected fruitbodies and ITS sequence analysis, this fungus was identified as Trametes hirsuta. This is the first report of T. hirsuta on Paulownia tomentosa in Serbia. Irregularly performed pruning as the possible infection route and the implications of these findings are discussed. 相似文献