Biotechnical Faculty

Ljubljana, Slovenia

Biotechnical Faculty

Ljubljana, Slovenia
Time filter
Source Type

Brus R.,Biotechnical Faculty | Idzojtic M.,University of Zagreb
Plant Biosystems | Year: 2011

In most European countries, the service tree (Sorbus domestica L.) is a rare and threatened species and its conservation has been recognised as a priority. The aim of this study was to asses its morphologic variation in the western and central part of the Balkan Peninsula and in southern Central Europe. Three populations were analysed: one in Serbia, one in Bosnia and Herzegovina and one in Slovenia. In each population 30 trees were selected, and from each tree 30 leaves were collected for morphometric analysis based on nine leaflet morphological traits. Univariate (ANOVA) and multivariate (MANOVA) analysis of variance were used to estimate the variation within- and between populations and a discriminant analysis was performed to examine the structure of the between-population differences. The values of particular morphological traits found in our study did not differ considerably from the values reported elsewhere. The results revealed significant within- and between population variation. Variation within populations was highly significant for all the scored leaf morphological traits, while variation between populations was significant for all the studied traits except for the leaflet length. The discrimination between the three populations was significant. High percentages of correctly classified samples demonstrate good discriminating employability of the analysed leaf morphological traits and indicate differentiation of the analysed populations. © 2011 Società Botanica Italiana.

Bohinc T.,Zgornja Lipnica 9a | Trdan S.,Biotechnical Faculty
Journal of Food, Agriculture and Environment | Year: 2012

In 2009 and 2010, a field experiment was carried out to determine the effect of three trap crops (oil radish, oil rape and white mustard) as a protection method against cabbage stink bugs (Eurydema spp.) and flea beetles (Phyllotreta spp.) attack on two hybrids of white cabbage. The experiment was designed as randomized complete block with four treatments. The damage caused by cabbage stink bugs and flea beetles on the main crop and the trap crops was estimated in 10-day intervals. Oil rape was the most attractive trap crop for cabbage stink bugs, while flea beetles displayed specific preference to oil radish as a trap crop in 2010. Flea beetles displayed specific preference for oil radish as a trap crop in 2010, while they did not display specific preference to any of trap crops tested in 2009. The damage caused by cabbage stink bugs on cabbage started increasing in the beginning of July. The damage caused by flea beetles, on the other hand, started increasing at the end of May. Cabbage hybrid 'Hinova' was more heavily attacked by both groups of the pests, mostly due to its longer growth period. The extent of damage on cabbage and trap crops was higher in the second year, since before 2009 no Brassica crops were grown in the near vicinity of the experimental plot. The trap crop species has no important effect on the yield of cabbage, since the pests on trap crop plants were not control with insecticides.

Modic M.,Jozef Stefan Institute | Junkar I.,Jozef Stefan Institute | Stana-Kleinschek K.,University of Zagreb | Kostanjsek R.,Biotechnical Faculty | Mozetic M.,Jozef Stefan Institute
Plasma Processes and Polymers | Year: 2014

Improved hemocompatibility from the perspective of platelets adhesion and activation on polyethylene terephthalate surfaces has been addressed. The activation stage of platelets has been determined from their size and morphology using scanning electron microscopy (SEM). The activation of platelets on untreated polymer materials was very intensive. Polymer materials were treated with weakly ionized oxygen plasma in order to repel platelet adhesion. Already short treatment times (3s) showed significant reduction of the total number and of highly activated forms of adhered platelets. Possible mechanisms of different behaviour of blood platelets on plasma treated polymer were discussed in terms of surface adhesion and changes in morphology. RF oxygen plasma treatment is used for surface modification of polyethylene terephthalate polymer surface. Newly acquired surface properties analyzed with XPS, WCA, and AFM show significant improvement of hemocompatibility. In contact with whole human blood, SEM images revealed reduced number of activated adhered platelets on the surface of plasma treated polymer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

News Article | March 1, 2016

Olms are explicitly blind salamanders, and just in time for "Game of Thrones" Season 6 premiere, scientists and tourists in Slovenia are eagerly awaiting the rare birth of olms or "baby dragons." A mother olm has been guarding her eggs fiercely at a cave in Postojna, Slovenia. Tourists are welcome to catch a glimpse of the "Dragon Mom" and her 55 olm eggs but it would take four more months to see if the eggs will hatch or not. Olms are small and have snake-like bodies. They lay eggs just one every 10 years, which makes a hatching a rare phenomenon to watch. If an olm egg successfully hatches, the new "baby dragon" can live for up to a century. The Postojna Cave is already a popular tourist site in Slovenia. Last Jan. 30, a tour guide noticed a just single olm egg; however, the cave now holds 55 tiny olm eggs. Since then, the hatching vigil has become another feature to see in the Postojna Cave. "[We saw] what we had waited and hoped for all along - the olms' embryonic development with visible cell division. To put it simply: it looks like the little 'dragons' are growing," said biologist Lilijana Bizjak Mali from Ljubljana's Biotechnical Faculty who visited the site. The team has put up a live coverage of from the Postojna Cave aquarium so visitors can see the daily status of the "Dragon Mom" and her eggs. Many visitors have shown interest and have continually asked when the "little dragons" will arrive and how many they will be. Unfortunately, other cave creatures have also shown interest in the olm eggs, particularly small crustaceans and cave amphipods. These cave creatures consider olm eggs special delicacies. The threat has also shown how ferocious a maternal instinct can be. Despite her blindness, the "Dragon Mom" has been successful in keeping the predators at bay, so far. In a water temperature of about 11 degrees Celsius, an olm egg requires 120 days to develop. However, in caves that are 2 degrees Celsius colder, the eggs need longer time to hatch. The olm mother is also getting help from a team of biologists. A safe haven has been created for them; however, the team is unsure how many of the 55 olm eggs will successfully hatch. Early estimates suggest only three will make it. According to the International Union for Conservation of Nature (IUCN) Red List Of Threatened Species, the olm or baby dragon is considered "vulnerable." Therefore, scientists are carefully monitoring the eggs' development in the Postojna Cave.

Cojzer M.,ZGS | Brus R.,Biotechnical Faculty
Sumarski List | Year: 2010

In Slovenia, as well as in others parts of Europe, the share of abandoned agricultural land overgrown by forest has been increasing every year. This article deals with this process of succession in Haloze, in the northeastern part of Slovenia. The main aim of this research was to find out how much of the abandoned agricultural land on the studied area has succeeded to forest in the last 20 years, to examine differences in species composition and the density of individuals of tree and shrub species between abandoned areas and younger developmental phases of forest, as well as to point out the strategies of succession on abandoned areas and compare them with the vegetation process of younger developmental phases in forest. Forest area increased by 7% in the period from 1985 to 2005 in the study region. The results show that the successional process on abandoned land starts with shrub species, while in younger phases of forest, tree species prevail entirely.

Schmitzer V.,Biotechnical Faculty | Veberic R.,Biotechnical Faculty | Osterc G.,Biotechnical Faculty | Stampar F.,Biotechnical Faculty
Journal of the American Society for Horticultural Science | Year: 2010

In the present study, the chemical and morphological status of eight cultivars of groundcover rose (Rosa×hybrida) with a range of flower colors was investigated. From the methanolic extracts of rose petals collected from flowers at four developmental stages, several phenolic compounds were identified via high-performance liquid chromatography/mass spectrometry, including five anthocyanins, which are especially important for the visual attributes of rose flowers. Colorimetric parameters were also measured and correlated with total anthocyanins and cell sap pH levels. During flower development from bud to senescent stage, a significant trend was detected; lightness (L*) increased, b* decreased in all analyzed roses, and a* decreased in pink and red cultivars. Cell sap pH level increased from bud to senescent petals; fresh weight, dry weight, and water content increased to fully open stage and were then reduced in senescent petals. Total anthocyanin and quercetin content increased from bud stage to fully open flowers, and was decreased in senescent ones. However, the highest content of total phenolics was measured in buds and partially opened flowers, respectively. Three distinct groups were formed according to the content of total anthocyanins and quercetins; white cultivars were most distant from the red ones, which were similar to the pink and light red cultivars.

Popovski S.,Biotechnical Faculty | Celar F.A.,Biotechnical Faculty
Acta Agriculturae Slovenica | Year: 2013

Several phytopathogenic Fusarium species occurring worldwide on cereals as causal agents of 'head blight' (scab) of small grain cereals and 'ear rot' of maize, are capable of accumulating, in infected kernels, several mycotoxins some of which of notable impact to human and animal health. Fusarium graminearum, F. culmorum, F. poae, F. avenaceum and Microdochium nivale predominantly cause Fusarium diseases of small-grain cereals. Maize is predominantly attacked by F. graminearum, F. moniliforme, F. proliferatum and F. subglutinans. The review is focused on the influence of climatic variables, particularly temperature, humidity and rainfall on growth, reproduction, survival, competitive ability, mycotoxicity and pathogenicity of Fusarium fungi commonly isolated from wheat, barley and maize.

Poljansek S.,Slovenian Forestry Institute | Ballian D.,University of Sarajevo | Nagel T.A.,Biotechnical Faculty | Levanic T.,Slovenian Forestry Institute
Tree-Ring Research | Year: 2012

We describe the development of the first black pine (Pinus nigra Arnold) regional chronology for the central-western Balkan area, Bosnia and Herzegovina (BiH), based on seven site chronologies from different parts of the country. Pointer-year analysis identified a common signal (possibly climate) in the site chronologies - at least five positive (1876, 1930, 1941, 1969) and nine negative pointer years (1874, 1880, 1891, 1931, 1943, 1963, 1971, 1987, 2000) are common to all seven study sites. Site chronologies were compared using statistical parameters and visual crossdating, from which we constructed a 435-year-long tree-ring width chronology for P. nigra for BiH and compared it with existing P. nigra chronologies from Montenegro, Greece, Albania, Austria (Vienna region), and France (Corsica). The resulting statistical and visual similarity indicated that the chronology has a strong regional signal and therefore can be included in the dendrochronological network for P. nigra for the Western Balkans. © 2012 the Tree-Ring Society.

Cater M.,Slovenian Forestry Institute | Diaci J.,Biotechnical Faculty | Rozenbergar D.,Biotechnical Faculty
Forest Ecology and Management | Year: 2014

Montane forests of silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.) in the Dinaric region are the largest continuous forest area in Central Europe, where silver fir's regression is one of the region's major concerns. Designing appropriate sized canopy gap spatio-temporal dynamics is the main silvicultural tool for indirect promotion of silver fir. Within gap microsites, categories based on shares of direct and diffuse radiation proved to be an interesting conceptual model for explaining microsite variation and seedling success induced by light and general climate variability. In order to evaluate the response of beech and fir in different gap microsites, different light regimes were evaluated based on the proportion between direct and diffuse radiation in three different sizes of forest gap in managed forests. The photosynthesis response to different light conditions (max. photosynthetic rate - Amax and quantum yield - Φ) in beech and silver fir was compared on all microsites during three consecutive g periods (2009, 2010, and 2011) under controlled environmental conditions. A different response between species in microsite light categories was shown between different gap sizes. In all microsite categories of both species, quantum yield appeared at lower light intensities with increasing gap size, with the exception of beech with a predominant direct light component, in which yield significantly increased. In order to favour fir, gaps with low direct light levels should be created, while existing gaps should be extended towards the southern gap edge. Our conclusions emphasize the importance of gaps, relatively smaller in size (0.03-0.11. ha) but significant in contributing to increasing the competitive advantage of fir in mountainous, mixed-species Dinaric forests. © 2014 Elsevier B.V.

Poljansek S.,Slovenian Forestry Institute | Ceglar A.,Biotechnical Faculty | Levanic T.,Slovenian Forestry Institute
Climate of the Past | Year: 2013

We present the first summer sunshine reconstruction from tree-ring data for the western part of the Balkan Peninsula. Summer sunshine is tightly connected with moisture stress in trees, because the moisture stress and therefore the width of annual tree-rings is under the influence of the direct and interactive effects of sunshine duration (temperature, precipitation, cloud cover and evapotranspiration). The reconstruction is based on a calibrated z-scored mean chronology, calculated from tree-ring width measurements from 7 representative black pine (Pinus nigra Arnold) sites in Bosnia and Herzegovina (BiH). A combined regression and scaling approach was used for the reconstruction of the summer sunshine. We found a significant negative correlation (r Combining double low line −0.54, p < 0.0001) with mean June-July sunshine hours from Osijek meteorological station (Croatia). The developed model was used for reconstruction of summer sunshine for the time period 1660-2010. We identified extreme summer events and compared them to available documentary historical sources of drought, volcanic eruptions and other reconstructions from the broader region. All extreme summers with low sunshine hours (1712, 1810, 1815, 1843, 1899 and 1966) are connected with volcanic eruptions. © Author(s) 2013.

Loading Biotechnical Faculty collaborators
Loading Biotechnical Faculty collaborators