Upotreba različitih metoda sterilizacije semena suncokreta u prevazilaženju endogene bakterijske infekcije

During culture of protoplasts in agarose droplets, permanent problem was bacterial infection. It was assumed that the seeds are the origin of infection, so different sterilization methods were tested in order to overcome this problem. Germination, infection of seeds and hypocotyls and their growth were examined. Based on these parameters, the best result was obtained with the combined use of 5% commercial bleach and dry heating at 45°C.Prilikom kultivacije protoplasta gajenog suncokreta u kapljicama agaroze stalan problem je bila bakterijska infekcija. Kako je pretpostavljeno da je seme izvor ove infekcije, isprobane su različite metode njegove sterilizacije da bi se pokušao prevazići ovaj problem. Praćeni su klijavost semena, broj infekcija semena i hipokotila, kao i njihov rast. Na osnovu ovih parametara najbolji rezultat je dobijen nakon kombinovane upotrebe 5% varikine i suve sterilizacije semena na 45°C

Upotreba biotehnoloških i metoda molekularne biologije u oplemenjivanju suncokreta - dostignuća u svetu

Sunflower is one of four the most important oil crops in the world. Over the past decade yield and world sunflower production has increased by 70%. This success has resulted both from the optimization of agricultural technology and breeding for more productive hybrids. However, the development of serious diseases caused by Phomopsis and Sclerotinia sp., and the high industrial demands concerning quality implies the introduction of new genetic characteristics in the sunflower genome. Biotechnology involving modern tissue culture, cell biology and molecular biology offers the opportunity of widening cultivated sunflower genetic base and developing new germplasms, better adapted to the new market and production demands. In this paper a review is given of biotechnological and techniques of molecular biology successfully used in sunflower breeding. Special attention was payed to the results presented at 15th International Sunflower Conference.Suncokret spada među četiri najvažnije uljane kulture u svetu. Tokom protekle dekade prinos i proizvodnja suncokreta u svetu su porasli za 70%, što je posledica optimizacije agrotehničkih mera kao i stvaranja sve produktivnijih hibrida. Ipak, pojava opasnih oboljenja izazvanih Phomopsis i Sclerotinia sp. i povećani zahtevi industrije u pogledu kvaliteta su doveli do potrebe uvođenja novih genetskih svojstava u genom gajenog suncokreta. Biotehnologija, odnosno moderna kultura tkiva, biologija ćelije i molekularna biologija pružaju mogućnost proširenja genetske osnove gajenog suncokreta i stvaranja nove germplazme, bolje adaptirane na nove zahteve tržišta i proizvodnje. Intenzivan rad u ovim oblastima je na suncokretu započet ranih sedamdesetih. U radu je dat pregled biotehnoloških i molekularnobioloških tehnika koje su sa uspehom upotrebljene u oplemenjivanju suncokreta u svetu, sa naglaskom na dostignuća predstavljena na XV Međunarodnoj konferenciji o suncokretu

Use of methods of biotechnology and molecular biology in unflower breeding - achievements in the world

Suncokret spada među četiri najvažnijie uljane kulture u svijetu. Tijekom protekle dekade prinos i proizvodnja suncokreta u svijetu su porasli za 70%, što je posljedica optimizacije agrotehničkih mjera kao i stvaranja sve produktivnijih hibrida. Ipak, pojava opasnih oboljenja izazvanih Phomopsis i Sclerotinia sp. i povećani zahtjevi industrije u pogledu kvalitete doveli su do potrebe uvođenja novih genetskih svojstava u genom uzgajanog suncokreta. Biotehnologija, odnosno moderna kultura tkiva, biologija stanice i molekularna biologija pružaju mogućnost proširenja genetske osnove uzgajanog suncokreta i stvaranja nove germplazme, bolje adaptirane na nove zahtjeve tržišta i proizvodnje. Intenzivan rad u ovim oblastima je na suncokretu započet ranih sedamdesetih. U radu je dat pregled biotehnoloških i molekularnobioloških tehnika koje su s uspjehom upotrijebljene u oplemenjivanju suncokreta u svijetu, s naglaskom na dostignuća predstavljena na XV. Međunarodnoj konferenciji o suncokretu.Sunflower is one of four the most important oil crops in the world. Over the past decade yield and world sunflower production has increased by 70%. This success has resulted both from the optimization of agricultural technology and breeding for more productive hybrids. However, the development of serious diseases caused by Phomopsis and Sclerotinia sp., and the high industrial demands concerning quality implies the introduction of new genetic characteristics in the sunflower genome. Biotechnology involving modern tissue culture, cell biology and molecular biology offers the opportunity of widening cultivated sunflower genetic base and developing new germplasms, better adapted to the new market and production demands. In this paper a review is given of biotechnologycal and techniques of molecular biology successfully used in sunflower breeding. Special attention was payed to the results presented at 15th International Sunflower Conference

Biochemical characteristics and nutrient content of the callus of sunflower inbred lines

Mineral nutrition is a factor affecting in vitro regeneration. Various requirements for individual mineral elements between plant species and also between genotypes of the same species have led to the differentiation and definition of the significance of the genetic background in determining callus biochemical characteristics and a confirmation whether different requirements for nutrients leave a possibility of achieving better and more efficient regeneration with a specific modification of substratum composition. The practical aspect of the obtained results lays in the fact that the sunflower species are characterized by low regeneration ability. It was shown that the dynamics of uptake and accumulation of mineral elements into callus cells is a genotype dependent trait being more or less evident depending upon element. Total nitrogen content was between 4 and 5%. The sunflower genotype PH-BC2-101A showed the highest accumulation of nitrogen phosphorus and, to some extent, calcium. Consequently, a high accumulation of total dry matter without pigment synthesis was recorded. A high nitrogen accumulation in the cited genotype resulting in the highest nitrate reductase activity a very high accumulation of soluble proteins (enzymes)

Theoretical analysis of tungsten carbide properties as electrocatalyst support for hydrogen electrode reactions

Elektrokatalizatori na bazi platine su uobičajeni za katalizu reakcija vodonične elektrode (engl. hydrogen evolution reaction - HER i hydrogen oxidation reaction - HOR) u različitim sistemima za konverziju energije, kao što su elektrolizeri i gorivne ćelije. Zbog visoke cene platine teži se povećanju specifične površine, da bi se poboljšalo iskorišćenje i smanjila ukupna cena katalizatora. Uobičajeni pristup koji se trenutno koristi u PEM sistemima (engl. PEM - polymer electrolite membrane ili proton exchange membrane – elektrolizeri ili gorivne ćelije sa polimernom membranom propusnom za protone kao elektrolitom) podrazumeva dispergovanje Pt-čestica dimenzija 5-10 nm na odgovarajućoj podlozi (ugljenik), ali u ovom slučaju jezgro Ptnanocestice ostaje nedovoljno iskorišćeno. Idealno iskorišćenje platine se postiže distribucijom platine u obliku monosloja (ML) na inertno provodno jezgro, što podrazumeva stvaranje posebne klase nano-strukturnih katalizatora nazvanih ''jezgroomotač'' (engl. core-shell). Na ovaj način postiže se smanjenje potrošnje platine za jedan red veličine. Karbidi prelaznih metala (engl. transition metal carbides – TMC)nalikuju grupi platinskih metala po elektronskim svojstvima i dimenzijama elementarne ćelije, što je podstaklo ispitivanje katalitičke aktivnosti za reakcije vodonične elektrode. Volfram-karbid (WC) pokazuje slične osobine kao i platina u smislu elektronske strukture i hemisorpcije vodonika. Ipak, dobijene gustine struje izmene su manje za 2-3 reda veličine u odnosu na platinske površine, čineći WC atraktivnim samo kao podlogu za katalizator. S druge strane, sinergijski efekat izmedju Pt i WC-podloge u smislu povećanja katalitičke aktivnosti se često spominje u literaturi, međutim, priroda ovog sinergizma nije u potpunosti razjašnjena. Pored platine, ostali metali platinske grupe su atraktivni za ispitivanje kao deo sličnih sistema, koji bi predstavljali neplatinske katalizatore. Ipak, tanki slojevi prelaznih metala do sada nisu sistematski ispitivani u smislu predviđanja i objašnjenja katalitičke aktivnosti i stabilnosti u uslovima reakcija vodonične elektrode kao neophodnog uslova za primenu. U ovom radu su, uz pomoć teorije funkcionala gustine (engl. Density functional theory - DFT) sistematski ispitani tanki slojevi metala (Cu, Ru, Rh, Pd, Ag, Ir, Pt i Au) na WC-podlozi. Posebna pažnja je posvećena monosloju i dvosloju Pt i Pd, uz analizu činilaca interakcije sa WC-podlogom na nivou elektronske strukture. Ispitivanje je prošireno i na monoslojeve drugih prelaznih metala, pri čemu je ukazano na mogućnost predviđanja stabilnosti do sada neispitanih sistema putem veze jačine vezivanja na WCpodlozi i kohezivne energije kao unutrašnjeg svojstva metala. U nastavku je diskutovana mogućnost predviđanja katalitičke aktivnosti površina na osnovu DFT izračunatih veličina, i konstruisana je vulkanska kriva koja povezuje DFT izračunate energije adsorpcije vodonika sa eksperimentalno dobijenim gustinama struje izmene, s obzirom na jednostavan pristup koji se više puta pokazao praktično primenljivim. Poseban osvrt napravljen je na aktivnost Pd i Pt tankih slojeva i na pojam i poreklo sinergije sa WC-podlogom. Od analiziranih monoslojeva najviše pažnje su privukli CuML/WC i RhML/WC, s obzirom na predviđenu aktivnost praktično jednaku Pt(111). Nijedan od ovih sistema nije do sad ispitivan kao katalizator za reakcije vodonične elektrode, a CuML/WC nije eksperimentalno ni pripremljen. Na osnovu teorijske analize, pre svega termodinamičkih, svojstava ovih sistema, ukazano je na mogućnost njihovog dobijanja u uslovima visokog vakuuma, kao i na očekivanu postojanost u uslovima rada vodonične elektrode. Opšti trendovi reaktivnosti na kraju su prodiskutovani i s tačke gledišta vodonik-supstrat interakcije na nivou elektronske strukture i dat je bliži uvid u činioce koji tu interakciju određuju. Dobijeni rezultati ukazali su na mogućnost dobijanja nove klase katalizatora za reakcije vodonične elektrode, zasnovane na pogodnom izboru kombinacije tankog sloja metala i podloge, koji uopšte ne sadrže platinu.Platinum based electrocatalysts are commonly used in catalysis of hydrogen electrode reactions (hydrogen evolution – HER and hydrogen oxidation - HOR) in different energy conversion systems, such as electrolyzers and fuel cells. For the reasons of high cost of platinum, efforts are made to enchance its utilization by broadening its specific surface. A typical state-of-the-art approach in PEM devices is based on dispersion of Pt-nanoparticles (5-10 nm) over appropriate support, such as carbon but in such arrangement Pt nanoparticle core still remains unexploited. Ideal Pt utilization is achieved when it is distributed in a form of monolayer (ML) over an inert conducting core, involving formation of a new class of nanostructured electrocatalysts called coreshell. In comparison to Pt-nanoparticles, Pt consumption is reduced by an order of magnitude. The transition metal carbides (TMC) are similar to Pt-group metals as far as electronic properties, as well as elemental cell dimensions are considered, what made them attractive for investigations of electrocatalytic activity towards hydrogen electrode reactions. Tungsten carbide (WC) shows similar properties as platinum, considering electronic properties and hydrogen chemisorption. However, obtained exchange current densities are still 2-3 orders of magnitude smaller than these on clean Pt-surfaces, limiting interests in WC to be applied as a catalyst support only. On the other side, synergy between Pt and WC-support in terms of increase of catalytic activity has been discussed in numerous studies, but its nature has not been completely clarified so far. Besides platinum itself, other platinum group metals are also attractive for investigations as part of similar systems, representing platinum-free catalysts. However, no systematic studies considering transition metal overlayers, prediction and explication of their catalytic activity, as well as stability in conditions of hydrogen electrode operation, have been published yet. In this work, thin layers of transition metals (Cu, Ru, Rh, Pd, Ag, Ir, Pt and Au) on WC support have been systematically investigated using Density Functional Theory (DFT). Special attention has been paid to Pd and Pt monolayer and bilayer, including factors determining metal-support interacton on the level of electronic structure. The research then has been extended to other transition metal monolayer systems, the correlation between metal-support binding energy and cohesive energy as intrinsic property of metals has been pointed out, and futher used to predict stability of systems which have not been examined experimentally so far. Hereinafter, the possibility to predict catalytic activity of surfaces from DFT calculations has been discussed, and the volcanic curve, correlating DFT calculated hydrogen adsorption energies with experimentally obtained exchange current densities, has been constructed, taking into account the simplicity and proved practical applicability of that approach. In particular, activity of Pd and Pt overlayers, the concept, as well as the origin of the synergy with WC-support, have been extensively discussed. On the other hand, among analyzed monolayers, CuML/WC and RhML/WC were the most interesting, because of their predicted catalytic activity practically equal to Pt(111). Neither of these systems has been examined yet as a catalyst for hydrogen electrode reactions, and CuML/WC has not even been prepared experimentally. Based on theoretical analysis of, basically thermodynamical, properties, the possibility to obtain these systems in UHV conditions, as well as expected stability in conditions of hydrogen electrode operation, have been pointed out. Finally, general reactivity trends have been considered from the point of view of hydrogen-substrate interactions, on the level of electronic structure, and the factors determining this interaction have been discussed. In general, results of this dissertation implied the possibility to obtain a new class of hydrogen electrode reaction catalysts, based on suitable combination of thin metal layer and the support, not containing platinum at all

Prenošenje otpornosti prema sclerotinia iz divljeg u gajeni suncokret - ocena divljih vrsta suncokreta

Accessions of H. mollis, H. maximiliani, H. rigidus and H. tuberosus were screened for resistance to Sclerotinia, during the two-year period (2001-2002). Artificial inoculation methods were used for that purpose. In the first year, only a stem resistance to Sclerotinia infection was observed, while in the second year, heads and stems of tested plants were infected by mycelia and sclerotia of this pathogen. Some differences in the response to mycelium and sclerotia infection within the same species were observed, as well as, differences in the response to sclerotial stem infection in different years. The H. mollis accession 1298 was found to be of a special interest for breeding as it was resistant to both head and stem infections with sclerotia.Populacije H. mollis, H. maximiliani, H. rigidus i H. tuberosus su testirane na otpornost prema Sclerotinia, tokom dvogodišnjeg perioda, upotrebom metoda veštačke inokulacije. U prvoj godini ispitivana je samo otpornost prema infekciji stabla sklerocijama, dok su u drugoj godini glave i stabla testiranih biljaka zaražavane i micelijom i sklerocijama ovog patogena. Tokom ispitivanja su uočene razlike u reakciji na infekciju micelijom i sklerocijama u okviru iste vrste, kao i razlike u reakciji na zaražavanje sklerocijama u različitim godinama. Populacija 1298 H. mollis se pokazala interesantnom za oplemenjivanje, pošto je bila otporna i na infekciju glave i na infekciju stabla sklerocijama

Use of oxalic acid for screening intact sunflower plants for resistance to Sclerotinia in vitro

Three sunflower inbred lines differing in resistance to Sclerotinia were grown on nutritive medium supplemented with different concentrations of oxalic acid. After two weeks of culture, plant height, fresh and dry weight of above-ground part, length of first pair of leaves, root length, and fresh and dry weight of root were measured. Data obtained were analysed using ANOVA and LSD test. Out of the tested parameters, plant height and root length were found to be the most reliable indicators of plant resistance/susceptibility to Sclerotinia. Based on the data obtained, oxalic acid concentrations of 4 mM, 3 mM and 2 mM were chosen for further work in which test would be done on a larger number of genotypes

Asimetrična somatska hibridizacija između suncokreta (Helianthus annuus L) i Helianthus maximiliani (schrad)

The transfer of interesting traits from wild Helianthus species into cultivated sunflower is limited by poor crossability or sterility of interspecific hybrids. To overcome this barrier, mesophyll protoplasts of Sclerotinia sclerotiorum-resistant clones of Helianthus maximiliani were electrically fused with hypocotyl protoplasts of Helianthus annuus. Fusion products were embedded in agarose and subjected to different regeneration protocols. The best result was obtained by the protocol of Trabace et al. 1995. Protoplasts grown on the L4 medium developed into microcalli. Subsequently they were released from the agarose and were transferred to the solid medium.Ukrštanje gajenog suncokreta sa divljim srodnicima primenom klasičnih metoda ukrštanja se često završava neuspehom. Da bi se prevazišao ovaj problem protoplasti izolovani iz listova Helianthus maximiliani, otpornog prema Sclerotinia sclerotiorum, su fuzionisani sa protoplastima iz hipokotila Helianthus annuus. Protoplasti su fuzionisani primenom električnih pulseva. Produkti fuzije su stavljeni u kapljice agaroze i gajeni prema različitim regeneracionim protokolima. Najbolji rezultati su dobijeni prema protokolu Trabace i sar., 1995. Protoplasti gajeni sa L4 podlogom su se delili do mikrokalusa. Oni su oslobođeni iz kapljica agaroze i prebačeni na čvrstu regeneracionu podlogu

Micropropagation of Helianthus maximiliani (Schrader) by shoot apex culture

H. maximiliani was micropropagated using culture of shoot apices on modified Murashige and Skoog medium (DV). Further propagation of in vitro grown plants was done by culture of their nodal segments and shoot tips on the same medium supplemented with phloridzin, silver nitrate and casein hydrolysate (DV'). Rooting was induced by dipping the explants into IBA solution prior culture. Viable protoplasts (90%) were isolated from leaf mesophyll. These protoplasts divided (18%) in culture in agarose droplets

Variability between helianfhus tuberosus accessions collected in the USA and Montenegro

Morphological variability between accessions of H. tuberosus collected in Montenegro and the USA was investigated as well as possible effect of long- term cultivation or its absence and growing in different environmental conditions on morphological traits of this species. Results obtained showed that there is a large similarity between some populations collected in Montenegro and those collected in the USA. This, along with the presence of a great cluster formed exclusively from Montenegrin populations, supports the hypothesis that there were two ways of introduction of H. tuberosus to Montenegro. In a group of populations, the changes in morphology were found, probably due to absence of cultivation