Variability and bimodal distribution of size in uninuclear microspores of Aesculus flava Marshall

Projekat ministarstva br. 14302

Comparative analysis of microspore size variability in the genus Aesculus (Hippocastanaceae)

Pollen size varies extensively among angiosperm species and partially reflects evolutionary adaptation of each species to the pollination and fertilization environment. Size of uninuclear microspores in Aesculus parviflora was analyzed and compared with the size of microspores in Aesculus hippocastanum, Aesculus carnea, and Aesculus flava. The microspores came from closed flower buds of different size (3, 4, and 5 mm) isolated from lower (female flowers), middle (bisexual flowers), and upper (male flowers) segments of inflorescences. Aesculus parviflora had smaller microspores than Aesculus carnea and Aesculus flava, but larger microspores than Aesculus hippocastanum. All analyzed microspores showed bimodal distribution in all investigated species of the genus Aesculus.Projekat ministarstva br. 14302

Rooting and preventing shoot-tip necrosis of in vitro cultured horse chestnut shoots

Efficient bud regeneration was achieved from germinating horse chestnut (Aesculus hippocastanum L.) somatic embryos cultivated on 1-10 μM benzyladenine (BA). Adventitious buds were detached from the mother tissue and used to establish permanent shoot cultures on 0-20 μM BA. Secondary buds were regenerated from the shoot base of the explants. Bud multiplication was very poor (1.9) and shoot-tip necrosis was very high (100%) on plant growth regulator (PGR)-free medium. The highest multiplication was achieved on 5 and 10 μM BA (16.8 and 18.7, respectively), with no shoot-tip necrosis, while hyperhydration was rather frequent on shoots cultivated on BA above 5 μM. Individual shoots were elongated on medium with 1 μM BA and 500 mg/l polyvinylpyrrolidone (PVP MW40 000) for 4 weeks. However, it was necessary to reduce BA level below 1 μM for shoot rooting and that caused mass shoot-tip necrosis. As classical rooting methods failed, the basal part of each elongated shoot was first wounded by cutting with a sterile blade and then dipped into a 0, 5 or 10 mM indole-3-butyric acid solution for 1 min and cultivated on solid half-strength MS PGR-free medium with 0.02% activated charcoal for 2-3 weeks. To prevent shoot tip necrosis during this phase, a BA solution was applied directly on apical meristem. Shoot-tip necrosis was completely eliminated by weekly application of 10 μl of 1 μM BA. As soon as the root initials were observed, the shoots were transferred to MS medium supplemented with 500 mg/l PVP and 5 μM BA. The frequency of rooting was 23%, and further optimisation of root-inducing phase is needed

Neanderthals on the Lower Danube: Middle Palaeolithic evidence in the Danube Gorges of the Balkans

The article presents evidence about the Middle Palaeolithic and Middle to Upper Palaeolithic transition interval in the karst area of the Danube Gorges in the Lower Danube Basin. We review the extant data and present new evidence from two recently investigated sites found on the Serbian side of the Danube River – Tabula Traiana and Dubočka-Kozja caves. The two sites have yielded layers dating to both the Middle and Upper Palaeolithic and have been investigated by the application of modern standards of excavation and recovery along with a suite of state-of-the-art analytical procedures. The presentation focuses on micromorphological analyses of the caves’ sediments, characterisation of cryptotephra, a suite of new radiometric dates (accelerator mass spectrometry and optically stimulated luminescence) as well as proteomics (zooarchaeology by mass spectrometry) and stable isotope data in discerning patterns of human occupation of these locales over the long term

Neanderthals on the Lower Danube: Middle Palaeolithic evidence in the Danube Gorges of the Balkans

The article presents evidence about the Middle Palaeolithic and Middle to Upper Palaeolithic transition interval in the karst area of the Danube Gorges in the Lower Danube Basin. We review the extant data and present new evidence from two recently investigated sites found on the Serbian side of the Danube River – Tabula Traiana and Dubočka-Kozja caves. The two sites have yielded layers dating to both the Middle and Upper Palaeolithic and have been investigated by the application of modern standards of excavation and recovery along with a suite of state-of-the-art analytical procedures. The presentation focuses on micromorphological analyses of the caves’ sediments, characterisation of cryptotephra, a suite of new radiometric dates (accelerator mass spectrometry and optically stimulated luminescence) as well as proteomics (zooarchaeology by mass spectrometry) and stable isotope data in discerning patterns of human occupation of these locales over the long term

The influence of genetic architecture on responses to selection under drought in rice

Accurately predicting responses to selection is a major goal in biology and important for successful crop breeding in changing environments. However, evolutionary responses to selection can be constrained by such factors as genetic and cross-environment correlations, linkage, and pleiotropy, and our understanding of the extent and impact of such constraints is still developing. Here, we conducted a field experiment to investigate potential constraints to selection for drought resistance in rice (Oryza sativa) using phenotypic selection analysis and quantitative genetics. We found that traits related to drought response were heritable, and some were under selection, including selection for earlier flowering, which could allow drought escape. However, patterns of selection generally were not opposite under wet and dry conditions, and we did not find individual or closely linked genes that influenced multiple traits, indicating a lack of evidence that antagonistic pleiotropy, linkage, or cross-environment correlations would constrain selection for drought resistance. In most cases, genetic correlations had little influence on responses to selection, with direct and indirect selection largely congruent. The exception to this was seed mass under drought, which was predicted to evolve in the opposite direction of direct selection due to correlations. Because of this indirect effect on selection on seed mass, selection for drought resistance was not accompanied by a decrease in seed mass, and yield increased with fecundity. Furthermore, breeding lines with high fitness and yield under drought also had high fitness and yield under wet conditions, indicating that there was no evidence for a yield penalty on drought resistance. We found multiple genes in which expression influenced both water use efficiency (WUE) and days to first flowering, supporting a genetic basis for the trade-off between drought escape and avoidance strategies. Together, these results can provide helpful guidance for understanding and managing evolutionary constraints and breeding stress-resistant crops

Improvement of maturation and conversion of horse chestnut androgenic embryos

Horse chestnut (Aesculus hippocastanum L., Hippocastanaceae) is a relict species of the tertiary flora and endemit of Balkan peninsula. It has enormous horticultular and medical important. Horse chestnut trees are native to the Balkan peninsula, but grow as ornamental trees in parks and avenues throughout the Northern Hemisphere. Because of the slow and difficult reproduction of great importance to be fast and cheap in vitro multiplication. Possible solution is regenerated by androgenesis. Microspore culture has been used in recent years as a tool for producing haploid plants in a varyety of higher plants, but the low frequencies of microspore-derived plants restrict the use of the technique in plant breeding

Ispitivanje karakteristika procednih voda deponije 'Vinča' metodom izluživanja

Under the newly implemented waste management policy in European Union countries, sanitary landfilling constitutes the fourth and the least preferred of the alternative management options for the disposal of solid urban wastes. Landfills generate emissions over long periods, often longer than a lifetime. The longest lasting emission is leachate: leachate production and management is now recognized as one of the greatest problems associated with the environmentally sound operation of sanitary landfills. These liquid wastes can cause considerable pollution problems by contacting the surrounding soil, ground or surface waters and, are therefore considered major pollution hazards unless precautionary measures are implemented. Landfill leachate characterization is a critical factor in establishing a corresponding effective management strategy or treatment process. This paper summarizes leachate quality indicators, and investigates the temporal variation of leachate quality from municipal solid waste. The toxicity of leachates from the municipal solid waste landfill "Vinča" in Belgrade, the capital of Serbia, was characterized using toxicity characteristics leaching procedures (TCLP). The "Vinca" landfill was established in 1978 as one of several municipal landfills. Since the 1990-ies the "Vinča" landfill has been the only operating landfill servicing the Belgrade Metropolitan area, the biggest city in Serbia, with 1,576,124 inhabitants in the larger-city area, and 1,273,651 inhabitants in the inner-city area. The total average amount of solid wastes deposited in the landfill is estimated to be 1100 tons/day. The landfill site is not lined and the tributary flows through the centre of the site-in some places directly under the mass of refuse. No consideration has been given to the protection of ground waters, surface runoff or drainage. Local authorities plan to expand the landfill by 0.4 km2 to a total of 1.3 km2. Chemical analysis was performed on the samples and the temporal variation of several parameters was monitored including pH, COD, chlorides, sulfates, nitrates, ammonia nitrogen, hardness, and heavy metals. The COD and pH were related to the biological activity within the landfill and the results indicated differences between the samples due to waste age. The concentrations of heavy metals, sulfates, nitrates, chlorides and ammonia nitrogen in the leachate were low, indicating their initially low amount in landfilled waste or their flushing with moisture contributing to a reduction in their concentrations.Komunalni čvrsti otpad iz Beograda odlaže se na deponiju "Vinca" od 1978. godine, a od 1987. do 2002. godine odloženo je oko 4.100.000 tona. Jedna od posledica odlaganja čvrstog otpada na deponiju jeste pojava procednih voda/filtrata. U okviru eksperimentalnog dela rada vršeno je izluživanje primenom TCLP metode (Toxicity Characteristic Leaching Procedure) uzoraka otpada koji su bili odloženi 6, 12 odnosno 24 meseca pre uzorkovanja. U rastvorima dobijenim izluživanjem koncentracije teških metala (Cu, Cd, Pb i Zn), hlorida, sulfata, amonijaka, nitrata i nitrita su bile niske, i nisu se znatno razlikovale za uzorke različite starosti. Dobijeni rezultati pokazali su da se pH vrednost i HPK (hemijska potrošnja kiseonika) menjaju u zavisnosti od starosti ispitivanog odloženog materijala, odnosno dostignutog stepena stabilizacije

A Contextual Study of Semantic Speech Editing in Radio Production

Radio production involves editing speech-based audio using tools that represent sound using simple waveforms. Semantic speech editing systems allow users to edit audio using an automatically generated transcript, which has the potential to improve the production workflow. To investigate this, we developed a semantic audio editor based on a pilot study. Through a contextual qualitative study of five professional radio producers at the BBC, we examined the existing radio production process and evaluated our semantic editor by using it to create programmes that were later broadcast. We observed that the participants in our study wrote detailed notes about their recordings and used annotation to mark which parts they wanted to use. They collaborated closely with the presenter of their programme to structure the contents and write narrative elements. Participants reported that they often work away from the office to avoid distractions, and print transcripts so they can work away from screens. They also emphasised that listening is an important part of production, to ensure high sound quality. We found that semantic speech editing with automated speech recognition can be used to improve the radio production workflow, but that annotation, collaboration, portability and listening were not well supported by current semantic speech editing systems. In this paper, we make recommendations on how future semantic speech editing systems can better support the requirements of radio production

Environmental study of heavy metals influence on soil and Tansy (Tanacetum vulgare L.)

The aim of this work was to define the correlation between heavy metal (mercury, lead, cadmium, chrome and nickel) concentration changes (in soil, leaf, stem, root and essential oil in Tansy) and type and distance from source pollution. The concentration was monitored on different locations: 1) Chemical industry pancevo (with accident situation); 2) Pancevo industrial zone; 3) highway; 4) Ada Ciganlija recreation zone and 5) Topcider park. Mercury (Hg) concentration was analyzed as a function of time, starting from accident situation from 1999 to 2008. Hg had maximum concentration of 131 200 mg/kg at a soil depth of 0 - 15 cm. After three, six and nine years, linear accident Hg concentrations in soil decreased from 85 400 via 41 060 to 106.0 mg/kg. Mercury concentration which results in the location where accident occurred showed that 6 years was necessary for concentration to drop below the limits and for revitalization of standard industrial Tansy vegetation. Concentrations of Hg in the Tansy plants from contaminated site were 5, 10, 100 and 200 times greater than in industrial zone, highway, Ada Ciganlija and Topcider, respectively. The highest amount of lead (Pb) was in leaves (14.1 mg/kg) and in essential oil (0.7 mg/kg) of Tansy near the highway. However, Pb concentration in soil and plant was decreased with square of highway distance.Ministry of Science and Environmental Protection of Serbia [143026, 18031