Photoluminescence and Raman spectroscopy of specific complexcompounds based on zinc, cobalt and copper suitable for application inorganic light emitting diodes

U okviru doktorske disertacije predstavljene su elektronska i fononska struktura odabranih organometalnih materijala koji u svom sastavu imaju metale cink, kobalt ili bakar i organsko jedinjenje piridoksalaminogvanidin (PLAG). Predstavljene su realizacija i karakteristike organske svetleće diode zasnovane na najboljem od ispitivanih materijala. Urađena je detaljna analiza fotoluminescentnih spektara i njihovo razlaganje na proste komponente koristeći Lorencov model. Izvršeno je poređenje sa od ranije poznatim materijalom koji pokazuje visok stepen luminescencije. S obzirom da istraživanja vezana za organske svetleće diode uzimaju sve veći zamah i da ove diode postaju sve prisutnije u industrijskoj serijskoj proizvodnji, napravljena je detaljna analiza ove tehnologije i mehanizama koji se kriju iza nje. Urađeno je podrobno istraživanje kako na nivou elektrona u datim supstancama, tako i na nivou sloja organske svetleće diode. Na kraju je izvršena analiza rada diode sa integrisanim slojem sa materijalom koji u sebi sadrži cink i PLAG.In this thesis electronic and phonon structure of specific organometallic materials which have zinc, cobalt, copper metals and organic compound pyridoxalaminoguanidin are presented. Implementation and characteristics of organic light emitting diode based on the best material among examined ones are also showed up. Detailed analysis of photoluminescence spectra was done and its decomposition to its elementar components using Lorentzian multipeak method. Comparison to well-known material that shows high level of luminescence was implemented. In accordance to the fact that research of organic light emitting diodes expands and that these diodes start to be more present in industrial serial production, detailed analysis of this technology and mechanisms behind it are made. Thorough research was done both on electron level in these substances and organic light emitting diode layer level. Finally, analysis of diode operation with integrated layer made of material which includes zinc and pyridoxalaminoguanidin compound is implemented

Mehanizmi adaptacije strnih žita na kiselost zemljišta

Acid soils limit crop production on 30-40% of the world's arable land and up to 70% of the world's potentially arable land. Over 60% of the total arable lands in Serbia are acid soils. Soil acidity is determined by hydrogen (H+) in soil solution and it is influenced by edaphic, climatic, and biological factors. Major constraints for plant growth on acid mineral soils are toxic concentrations of mineral elements like Al of H+ and/or low mineral nutrient availability due to low solubility (e.g. P and Mo) or low reserves and impaired uptake (e.g. Mg2+) at high H+ concentrations. Aluminum (Al) toxicity is primary factor limiting crop production on acid soils. This review examines our current understanding of mechanisms of Al-toxicity, as well as the physiological and genetic basis for Al-toxicity and tolerance. Inhibition of root growth by Al leads to more shallow root systems, which may affect the capacity for mineral nutrient acquisition and increase the risk of drought stress. Of the two principal strategies (tolerance and avoidance) of plants for adaptation to adverse soil conditions, the strategy of avoidance is more common for adaptation to acid mineral soils. At the same, the short view of the most important genetics tolerance mechanisms, developed and determined in some small grains genotypes, is showed as well.Kisela zemljišta ograničavaju biljnu proizvodnju na 30-40% ukupnih, kao i do 70% potencijalno obradivih svetskih površina. Kisela reakcija ovih zemljišta i nizak sadržaj najvažnijih biljnih hraniva, pre svega R i Sa su ograničavajući faktori postizanja visokih i stabilnih prinosa gajenih biljaka. Pored kisele reakcije, ova zemljišta karakteriše veoma često i povećan sadržaj toksičnih oblika Al, Fe i Mn, kao i nedostatak ili smanjena pristupačnost P, Ca, Mg i nekih mikroelemenata, posebno Mo, Zn i V. Toksičnost Al se smatra najvažnijim faktorom koji ograničava rast biljaka na kiselim zemljištima. Mehanizmi adaptacije strnih žita na kisela zemljišta mogu se podeliti na: spoljašnje, unutrašnje (fiziološke) i genetičke. Dejstvo spoljašnjih mehanizama tolerantnosti zasniva se na imobilizaciji Al u ćelijskom zidu, isticanju Al kroz plazma membranu, uspostavljanju pH barijere u rizosferi i lučenju organskih kiselina, fosfata, helata i drugih liganada korenom u spoljašnju sredinu. Unutrašnji mehanizmi tolerantnosti zasnivaju se na kompleksiranju Al sa proteinima, organskim kiselinama i enzimima, kao i helatiziranju u citoplazmi. Strna žita ispoljavaju različitu tolerantnost prema kiselosti zemljišta i povećanom sadržaju Al u zemljišnom rastvoru. Najosetljiviji je ječam, zatim pšenica, dok veću tolerantnost ispoljavaju ovas, tritikale i raž

Interrelationships between grain nitrogen content and other indicators of nitrogen accumulation and utilization efficiency in wheat plants

The topic of N wheat nutrition was prevalent during the last decades of the 20th century for many reasons such as energy crises, profitability of small grain production, and ecosystem protection and preservation. The objective of this study was to determine the interrelationships between wheat (Triticum aestivum L.) grain N content and other indicators of N nutrition efficiency to better understand the N nutrition process in wheat plants. The experiment included 30 wheat cultivars and experimental lines from Serbia. Plant samples of each genotype were taken at anthesis and maturity. The following parameters related to N accumulation and translocation within the wheat plant were calculated: N content (at anthesis, grain, straw, and total at maturity), N harvest index (NHI), N reutilization (N reU), and N lost (-) or gained (N post-anthesis). Our results showed that N content in the aboveground part of the plant expressed very strong direct positive effects on N yield (phenotypic coefficient 3.78** to 9.34** and genotypic coefficient 1.43** to 2.32**), while its indirect effects varied. The influence of independent variables on grain N content has been changing from year to year in a negative way. Total N accumulation (N total) had the highest negative direct effect in the first year of the study (phenotypic coefficient -2.11**), N total in the second (phenotypic coefficient -2.78**), and N reutilization in the third (phenotypic coefficient -8.49**). Genotypic coefficients indicate that the most frequent strong direct negative effect was N reutilization (-0.47** and -0.99** in the first 2 yr of research, respectively). Nitrogen reutilization and its current assimilation are very important and related to grain N supply processes. Their interaction leads to the conclusion that forming N yield is a very complex mechanism and, as a result, grain yield and quality. The abovementioned parameters could be considered as important criteria in wheat breeding to improve production efficiency and reduce adverse impacts of N fertilizers on the ecosystem

The components of variability of dry matter status indicators in wheat (Triticum aestivum L.)

Variability and components of variance for some dry matter status indicators (grain yield, biological yield and grain harvest index) have been studied in 30 winter wheat varieties from different selection centers (Morava, Lepenica, Studenica, Takovcanka, Toplica, Srbijanka, KG 100, Lazarica, Bujna, Matica, Vizija, Pobeda, Rana 5, Evropa 90, Renesansa, Tiha, Mina, Prima, Kremna, Rusija, Pesma, KG - 200/31, KG - 253/4 - 1, KG - 115/4, KG - 165/2, KG - 56/1, KG - 100/97, Perla, KG - 224/98 and KG - 10). The experiment was performed in randomized block design in five replications on the experimental field of Small Grains Research Centre, Kragujevac in three years. Average estimated values for grain yield, biological yield and grain harvest index differed high significantly among years and among varieties. The highest average value for grain yield had KG 10 variety (792.94g m-2) and the lowest value was found in KG 200/31 (303.88g m-2). During investigated period the highest average value for biological yield was determined in KG 10 (1907.62 g m-2), and the lowest value in Pesma (701.55). The grain harvest index varied from 39% (Lepenica, KG 200/31) to 46% (Renesansa, Tiha, KG 100/97). The lowest variability for grain yield was established in Rana 5 variety and the highest in Takovcanka (V = 9.60%; 27.71%, respectively). Coefficient of variation for biological yield varied from 4.02% (Matica) to 28.85% (Evropa 90). The lowest variability for grain harvest index was established in Evropa 90 and the highest in Pesma (V = 5.46%; 23.49%, respectively). Phenotypic analysis of variance indicated that genetic factors had higher impact on the expression of GY and BY than ecological factors. Higher share of ecological variance was registered at variability of GHI

Sadržaj i pristupačnost bakra u smonicama Srbije

The soils samples of typical simonitza soils were collected from the plough layers at 10 locations in Serbia. The basic physical and chemical properties, as well as, the total and available Cu content in the soil were determined. The availability of Cu was also evaluated through the pot experiment with oat as a test plant. The regular, geochemical levels of the total Cu were found in our smonitza soils (mean 33.35 ppm, range 17-74 ppm). The available Cu content, determined after the extraction with different reagents (0.1 N HCl, DTPA and acid solution of NaOAc), was in correlation with its total content in the soil. The extraction efficiency of Cu from the soil varied (15.8%, 13.2% and 3.5%) in respect to its total content. The concentration of Cu in oat plants was about 11 ppm, with very low variations. This, as well as the statistically insignificant correlation coefficient between absorbed Cu and its content in the soil, indicates that the investigated smonitzas are well supplied with available Cu.Sa 10 lokacija u Srbiji uzeti su tipični uzorci smonica iz orničnih slojeva uporedo sa površina koje se koriste kao njive ili livade. U njima su utvrđene osnovne hemijske i fizičke karakteristike, ukupni bakar (Cu) i njegovi pristupačni oblici. Pristupačnost Cu iz ovih zemljišta je ocenjivana i preko ogleda u sudovima sa biljkama ovsa. U našim smonicama su nađeni normalni, geohemijski nivoi ukupnog Cu (srednja vrednost 33,35 ppm, sa intervalom 17-74 ppm). Sa njim je u korelaciji bio sadržaj pristupačnog Cu određen raznim metodama (0,1N HCl, DTPA i kiseli rastvor NaOAc), pri čemu je efikasnost ekstrakcije Cu iz zemljišta bila različita: 15,8; 13,2 i 3,5 % prema sadržaju ukupnog Cu. Koncentracija Cu u biljkama ovsa iznosila je približno 11 ppm, uz vrlo mala variranja. To i nepostojanje korelacija usvojenog Cu sa njegovim sadržajem u zemljištu govori o dobroj obezbeđenosti ispitivanih smonica u Srbiji sa pristupačnim Cu za ishranu biljaka

Liming increases alfalfa yield and crude protein content in an acidic silty loam soil

A three year field trial examined the effect of three hydrated lime (HL, Ca(OH)2) rates (0, 1.5 and 3 Mg HL ha-1) on yield and quality characteristics of alfalfa on an acid soil (pHwater 1:2.5 4.7) in Western Serbia. Lime was applied only once. Total dry mass yields of a new planting alfalfa (Medicago sativa L.) increased up to 6500% by the treatments of HL, compared with the untreated control. Lime application significantly (P ≤ 0.05) increased the crude protein content of alfalfa, in comparison to the no limed control. Liming also significantly increased Ca, K, and P concentrations but decreased Mg, Fe, Mn, Zn, and Al concentrations in alfalfa tissue, compared with the control treatment. Alfalfa yield increase was attributed to the increase of Ca, P and K uptake. Furthermore, the low (1.5 Mg HL ha-1) and high (3 Mg HL ha-1) lime treatments increased soil pH even further by 0.9 and 1.5 pH units, respectively. The results suggest that an initial application of hydrated lime at a rate of 3 Mg HL ha-1 may ameliorate soil acidity and increase the yield and quality characteristics of alfalfa at least over a 3-year period.Keywords: Alfalfa, soil acidity, liming, herbage yield, elemental compositio

Distribucija i forme gvožđa u vertisolima Srbije

Soil of arable land and meadows from the Ap horizon, taken from ten different localities, were investigated for different forms of Fe, including total (HF), pseudo-total (HNO3), 0.1 M HCl extractable and DTPA (diethylenetri-aminepentaacetic acid)-extractable. A sequential fractional procedure was employed to separate the Fe into fractions: water soluble and exchangeable Fe (I), Fe specifically adsorbed with carbonates (II), reducibly releasable Fe in oxides (III), Fe bonded with organic matter (IV) and Fe structurally bonded in silicates (residual fraction) (V). The soil pH, cation exchange capacity, and size fractions (clay and silt) had a strongest influence on the distribution of the different forms of Fe. The different extraction methods showed similar patterns of the Fe content in arable and meadow soils. However, the DTPA iron did not correspond with the total iron, which confirms the widespread incidence of iron-deficiency in vertisols is independent of the total iron in soils. The amount of exchangeable (fraction I) and specifically adsorbed (II) iron showed no dependence on its content in the other fractions, indicating low mobility of iron in vertisols. The strong positive correlation (r = 0.812 and 0.956) between the content of iron in HNO3 and HF and its contents in the primary and secondary minerals (fraction - V) indicate a low content of plant accessible iron in the vertisol. The sequential fractional procedure was confirmed as suitable for accessing the content and availability of iron in the vertisols of Serbia.U cilju određivanja različitih oblika gvožđa u nekim varijetetima vertisola sa područja Srbije (oranice i livade) poreklom sa deset različitih lokaliteta analiziran je ukupan sadržaj gvožđa (HF), pseudo-ukupan sadržaj (HNO3), 0,1 M HCl rastvorljivo i DTPA rastvorljivo gvožđe. Sekvencijalnom ekstrakcijom izvršeno je razdvajanje frakcija gvožđa na rastvorljivo u vodi i razmenljivo Fe (I), specifično absorbovano gvožđe sa karbonatima (II), okludovano Fe u oksidima (III), Fe vezano za organsku materiju (IV) i Fe strukturno vezano u silikatima (rezidualni deo, V). pH vrednost zemljišta, CEC i veličina frakcija (glina i prah) imali su značajan uticaj na distribuciju različitih oblika gvožđa. Različite metode ekstrakcije su pokazale sličan oblik sadržaja Fe u obradivom zemljištu i livadi. Međutim, sadržaj DTPA rastvorljivog gvožđa ne odgovara ukupnom sadržaju, što potvrđuje da je učestalost nedostatka gvožđa u vertisolima na području Sr- bije nezavisna od ukupnog gvožđa u zemljištima. Iznos razmenljivog gvožđa (frakcija I) i adsorbovovanog (II) gvožđa nije pokazala zavisnost od njegovog sadržaja u drugim frakcijama, što ukazuje na nisku mobilnost gvožđa u proučavanim vertisolima. Jaka pozitivna korelacija (r = 0,812 i 0,956) između sadržaja gvožđa u HNO3 i HF i njegov sadržaj u primarnim i sekundarnim mineralima (frakcija V) pokazuju nizak nivo gvožđa dostupnog biljkama u ispitivanim vertisolima. Korišćenjem sekvencijalne ekstrakcije moguće je utvrditi sadržaj i pristupačnost gvožđa u vertisolima Srbije

Effects of fertilization on yield and grain quality in winter triticale

Study of fertilization effects were conducted in a stationary type of field trial, on a degrading vertisol soil with low pH. Eight variants of mineral nutrition (NK, NP1, NP2, NP3, NPIK, NP2K and NP3K) and untreated control (without nutrition) were tested in the experiment. The rates of nitrogen application were 80 kg N ha(-1), and they were applied either individually or in combination with three phosphorus rates and the potassium fertilizer. The highest grain yields under mineral nutrition involving a combination of three mineral elements were: N, P and K (80 kg N ha(-1), 60 kg P2O5 ha(-1), 60 kg K2O ha(-1)), and under NP2K treatment at a rate of 80 kg N ha(-1), 80 kg P2O5 ha(-1) and 60 kg K2O ha(-1). Based on the analysis of variance, it can be concluded that there were highly significant differences in grains yield among years of investigation and highly significant differences at 1000-grain weight and grain test weight

Distribution and forms of iron in the vertisols of Serbia

Soil of arable land and meadows from the Ap horizon, taken from ten different localities, were investigated for different forms of Fe, including total (HF), pseudo-total (HNO3), 0.1 M HCl extractable and DTPA (diethylenetriaminepentaacetic acid)-extractable. A sequential fractional procedure was employed to separate the Fe into fractions: water soluble and exchangeable Fe (I), Fe specifically adsorbed with carbonates (II), reducibly releasable Fe in oxides (III), Fe bonded with organic matter (IV) and Fe structurally bonded in silicates (residual fraction) (V). The soil pH, cation exchange capacity, and size fractions (clay and silt) had a strongest influence on the distribution of the different forms of Fe. The different extraction methods showed similar patterns of the Fe content in arable and meadow soils. However, the DTPA iron did not correspond with the total iron, which confirms the widespread incidence of iron-deficiency in vertisols is independent of the total iron in soils. The amount of exchangeable (fraction I) and specifically adsorbed (II) iron showed no dependence on its content in the other fractions, indicating low mobility of iron in vertisols. The strong positive correlation (r = 0.812 and 0.956) between the content of iron in HNO3 and HF and its contents in the primary and secondary minerals (fraction – V) indicate a low content of plant accessible iron in the vertisol. The sequential fractional procedure was confirmed as suitable for accessing the content and availability of iron in the vertisols of Serbia