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Considering the very important role of nitrogen in plant life cycle, parameters of plant nitrogen nutrition efficiency represent a group of physiological traits suitable to contemporary wheat breeding aims. Therefore, the objectives of the study were to estimate variability of nitrogen nutrition efficiency indicators and to estimate their heritability in wheat. The experiment included 30 wheat cultivars and experimental lines, originating from Serbia: Small Grains Research Center and Institute of Field and Vegetable Crops, Novi Sad. The variability and broad - sense heritability of total nitrogen accumulation (ANt) at maturity, grain harvest index (GIII) and physiological efficiency of nitrogen (PEN) were analysed. The years when the researches were carried out had a highly significant effect on all tested indicators, as well as genotype and interaction year x genotype. Total nitrogen accumulation in mature plant was the most variable indicator (Cv 13.91%), while lower variability was registered for nitrogen harvest index and physiological efficiency of nitrogen (5.81% and 5.59% respectively). NHI heritability was lower (0.52) compared to the ANt and PEN (0.66 and 0.69, respectively). On the other hand, heritability of ANt and PEN were almost the same, but PEN was more repeatable than the ANt.

Methyl tertiary butyl ether (MTBE) belongs to the group of gasoline oxygenates and persistent environment contaminants, and shows potential for biodegradation in aerobic and anaerobic conditions, through application of pure microbial cultures. Presented research shows that indigenous bacterial isolates 6sy and 24p, selected from oil hydrocarbons-contaminated environments, were capable of utilizing MTBE as sole carbon and energy source. Based on 16S rDNA sequence analysis, bacterial isolates 6sy and 24p were identified as Staphylococcus saprophyticus subsp. saprophyticus and Pseudomonas sp., respectively. The MTBE biodegradation rate was affected by longevity of incubation period and initial MTBE concentration. After 3 weeks of incubation at 25 degrees C in a dark, the removal rates of initial 25 and 125 ppm MTBE concentrations by Staphylococcus saprophyticus 6sy were found to be 97, and 63%, respectively, while efficiency of Pseudomonas sp. in degradation of indicated concentrations was 96, and 40%, respectively. Both bacterial isolates were able to grow in MTBE-containing growth medium. Highest growth rate of bacterial isolates was observed at the end of incubation period. The presented results indicated the potential of these bacterial isolates in bioremediation of MTBE-contaminated environments.

The topic of nitrogen for wheat nutrition has become quite important over the last few decades for many reasons. The most important are the energy crises and the escalation of the price of fertiliser, causing a decrease in profitability of small grains production and an adverse impact from the excessive use of nitrogen (N) fertiliser on the ecosystem and the production healthy safe food. Despite the detrimental impacts, the use of chemical fertilisers, especially N in agriculture, together with an improvement in cropping systems (mainly in developed countries), has provided a food supply sufficient for both animal and human consumption. Therefore, the challenge for the next few decades, considering the expanding world population, will be to develop highly productive agriculture, whilst at the same time preserving the quality of the environment. A selection approach to this issue is to identify winter wheat genotypes efficient in absorption and utilisation of soil nitrogen, which would be desirable for both practical production and breeding programs. Consequently, this paper deals with an evaluation of Serbian winter wheat genotypes in terms of some indicators of their nitrogen absorption and utilisation efficiency. Genotypes KG 10, Evropa 90, and Morava were the most efficient at nitrogen accumulation in the aboveground part of plant during the phases of anthesis, grain, straw, and total nitrogen accumulation at maturity. The best nitrogen partitioning between grain and straw was registered in the genotypes KG 165/2, Pobeda and Bujna. Prima, Lepenica and Studenica had the most efficient reutilization of nitrogen, which accumulated in the plant until anthesis, while the genotypes KG 200/31, KG 253/4-1 and KG 10 expressed the greatest ability to continue nitrogen assimilation during the reproductive period. Genotypes, selected as superior in absorption and utilization of nitrogen, are considered the carriers of desirable traits in terms of wheat breeding theory, impro

Kontaminacija zemljišta teškim metalima predstavlja predmet velikog broja istraživanja tokom poslednjih godina. U tom smislu tehnologije remedijacije napreduju sa kontinuiranim razvojem i usvajanjem novih tehnologija u cilju efikasnije dekontaminacije zagađenog zemljišta. Bioremedijacija predstavlja zelenu tehnologiju koja koristi biološku aktivnost mikroorganizma za uklanjanje zagađujućih supstanci iz zemljišta. Mikroorganizmi imaju važnu ulogu u transformaciji teških metala i srodnih supstanci iz zemljišta. Mehanizmima, mobilizacije ili imobilizacije, koji su sastavni delovi prirodnih biogeohemijskih ciklusa metali se prevode u manje toksične oblike. Mobilizacija metala dešava se kroz različite procese ispiranja (luženja), kompleksiranja sa proizvodima metabolizma mikroorganizama ili sideroforama i metilacije. Imobilizacija se ogleda u usvajanju metala biomasom ili egzopolimerima, intraćelijskim transportom, ili mehanizmima redukcije i precipitacije. Ovim radom su predloženi i objašnjeni najvažniji mehanizmi mikrobioloških procesa u cilju njihove primene u bioremedijaciji zemljišta zagađenog teškim metalima., In the recent years soil contamination with heavy metals has been the subject of many studies and researches, so that the field of remediation has grown and evolved, continually developing and adopting new technologies in attempts to improve the decontamination. Bioremediation represent a green technology which uses biological activity of microorganisms in decontamination of polluted soils. Microorganisms play a pivotal role in the heavy metal transformation of contaminated soils. With mechanisms, that are an integral part of natural biogeochemical cycle's, metals are transformed into less toxic forms. Main mechanisms are divided into two groups: mobilization and immobilization. Mobilization of heavy metals consists of metal leaching, complex formation, with microorganism metabolism products or siderophores, and methylation. Moreover, immobilization suggests metal absorption into biomass or within exopolymers, via intracellular transport, or various mechanisms of metal reduction or precipitation. In this work summary of the most important microbial transformation mechanisms has been given as the aim of their usage in bioremediation of heavy metal polluted sites.

Methyl tertiary butyl ether (MTBE) belongs to the group of gasoline oxygenates and persistent environment contaminants, and shows potential for biodegradation in aerobic and anaerobic conditions, through application of pure microbial cultures. Presented research shows that indigenous bacterial isolates 6sy and 24p, selected from oil hydrocarbons-contaminated environments, were capable of utilizing MTBE as sole carbon and energy source. Based on 16S rDNA sequence analysis, bacterial isolates 6sy and 24p were identified as Staphylococcus saprophyticus subsp. saprophyticus and Pseudomonas sp., respectively. The MTBE biodegradation rate was affected by longevity of incubation period and initial MTBE concentration. After 3 weeks of incubation at 25°C in a dark, the removal rates of initial 25 and 125 ppm MTBE concentrations by Staphylococcus saprophyticus 6sy were found to be 97, and 63%, respectively, while efficiency of Pseudomonas sp. in degradation of indicated concentrations was 96, and 40%, respectively. Both bacterial isolates were able to grow in MTBE-containing growth medium. Highest growth rate of bacterial isolates was observed at the end of incubation period. The presented results indicated the potential of these bacterial isolates in bioremediation of MTBE-contaminated environments.

Air quality biomonitoring using plant leaves has been widely applied to assess the effects of atmospheric pollution. Although practiced for many years, it has not given completely satisfactory data, due to different and even opposing results. This study comprises an investigation on the content of some trace elements (Al, As, Ba, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Cd, Pb) in leaves of four tree species common for the urban area of Belgrade (Serbia). The assay took place in July 2009 when the selected trees (Acer platanoides, Aesculus hippocastanum, Betula pendula, Tilia cordata) were in the maximum of physiological activity during the vegetation season. Among the investigated species, leaves of A. platanoides contained the highest concentrations of the measured elements. The assumption that a large green area in the Belgrade city periphery would be a suitable control site appeared to be disputable due to the substantial load of the elements obtained in the leaves. It was shown that even a short rinse with bidistilled water (3-5 s), applied twice to the leaves prior to chemical analysis, led to a significant decrease of some element concentrations (most pronounced for Al, Fe and Pb in all species, but also evident for Cu, Cr, Co and Zn for some of them). However, by washing leaves, the representativeness of leaf samples per studied site could be improved due to removal of some superficial loosely adhered impurities and so diminished large variability of element concentrations among leaf subsamples providing more representative information on the element content in leaves per site, and the area, respectively.

Ekološka poljoprivreda, kao činilac održivog poljoprivrednog sistema, promoviše farmerski tip proizvodnje tj. mešovitu biljnu i stočarsku proizvodnju. U zahtevima za organizovanje organske stočarske proizvodnje ističu se uslovi za obezbeđenjem dovoljnih količina kvalitetne hrane, proizvedene po načelima ekološke poljoprivrede. To pretpostavlja obezbeđenje kvalitetne ispaše, slobodnog kretanja, neophodnih komfornih uslova gajenja, kao i koncentrovane i kabaste konzervisane hrane. Strna žita imaju veoma važnu ulogu u obezbeđenju potpune funkcionalne ishrane domaćih životinja. Raznolikost upotrebe, odgovarajući hemijski sastav, prihvatljiva i proučena tehnologija gajenja primenom principa i metoda organske proizvodnje, svrstavaju strna žita u nezamenljivi izvor energetskih i proteinskih potreba životinja. ., Ecological agriculture, as factor of sustainable agriculture system, promote eco farms as unity of plant and livestock production. An important principle in organic animal production organizing is to provide all livestock with good living conditions and keeping their natural behavior and needs. Living conditions have to consider the natural needs of the animals for free movement, social behavior, food, pastures and grassland areas, organically produced forage and concentrated feedstuffs, water, shelter, shade and direct unfiltered sunlight. Small grains have their important application in providing complete, functional livestock nutrition. Small grains represent irreplaceable source of energy and proteins for animals due to various possibilities of their use, adequate chemical composition, acceptable and studied growing technology, with application of organic farming principles and methods. .

Organski ratarski sistemi su značajni sa aspekta zaštite ekosistema i dobijanja proizvoda visoke nutritivne vrednosti. Generalno, u ekološkoj proizvodnji strnih žita zastupljene su sve agrotehničke mere kao i u konvencionalnom sistemu gajenja. Standardi organske odnosno ekološke proizvodnje, međutim, podrazumevaju značajne izmene u odnosu na konvencionalni tip ratarenja. Značajne promene se predviđaju u primeni mehanizacije, plodoredu, đubrenju i zaštiti biljaka. Osnova đubrenja i zaštite useva u ekološkoj proizvodnji jeste primena bio - preparata i dobro poznavanje specifičnosti sorti, biologije korova i prirode bolesti. Plodored je suštinska mera u organskom ratarenju i u kombinaciji sa združivanjem useva predstavlja način efektivnijeg iskorišćavanja i očuvanja plodnosti zemljišta. U osnovi preporučene tehnologije gajenja strnih žita u ekološkom sistemu jeste orijentacija na domaće sorte, očuvanje i pospešivanje biodiverziteta i briga o zemljištu. Značajna pomoć u unapređenju ekološkog odnosno organskog gajenja strnih žita očekuje se od selekcije i oplemenjivanja ovih vrsta za potrebe ovog sistema ratarenja. ., Organic farming systems are important for ecosystem protection and producing high nutritive values productions. Generally, the whole system of growing technology is applicable in ecological production of small grains like in conventional one, with certain changes in relation to it. The important changes will appear in application of some cultural practices like as soil tillage, crop rotation, fertilization and plant protection. The base of fertilization and plant protection in ecological agriculture is application of bio-preparations and good knowledge of cultivar characterizations, weed biology and diseases. Crop rotation is essential practice in the ecological system, which, combined with intercroping, represents the way of better usage and preservation of productive soils. The orientation to local varieties, preservation and enhancement of biodiversity and soil concerns are foundation of recommended small grains growing technology in ecological system. The improvement of ecological and organic small grains growing is expected from field of breeding these species according to the requirements of this type of farming. .

U radu su predstavljeni rezultat eksperimenata sa biljkom kana (Canna indica L.), koji su postavljeni u cilju dobijanja egzaktnih pokazatelja o potencijalu ove biljke za uklanjanje teških metala (olova) iz akvatičnih sredina i produkciji biomase. Teški metali, kao što su Cd, Hg, Pb, As, Tl i U i koji mogu da se detektuju u industrijskim i drugi otpadnim vodama nemaju biološku vrednost za žive organizme, već su izuzetno toksični i u relativno malim koncentracijama. Alternativne metode, koje koriste biljke za uklanjanje polutanata iz kontaminiranih voda, zemljišta i vazduha bi jednim imenom mogle da se nazovu fıtoremedijacija. Ovaj pojam se odnosi na raznovrsan kompleks tehnologija, koje se baziraju na upotrebi biljaka, prirodnih ili genetski stvorenih, radi uklanjanje polutanata iz životne sredine ili radi njihovog pretvaranja u netoksične oblike. Kana je samo jedna od biljaka, koja se u poslednje vreme sve više koristi u konstruisanim akvatičnim ekosistemima. Ona se u eksperimentima pokazala kao biljka vrlo tolerantna na odsustvo hranljivih materija i biljka koja može da stvara veliku količinu biomase. U vodi razvija izuzetno gust, jak i žiličast korenov sistem sa velikom površinom za usvajanje teških metala. Vrlo je tolerantna na prisustvo olova, koje lako usvaja i koncentriše u korenu i rizomu, jer je translokacija u nadzemne delove slaba., This paper presents the results of experiments with the plant Indian shoot (Canna indica L.), which were conducted in order to obtain the exact indicators of the plant potential for the removal of heavy metals (lead) from the aquatic environment and biomass production. Heavy metals such as Cd, Hg, Pb, As, Tl and U, which can be detected in industrial and other wastewaters have no biological value for living organisms, but are extremely toxic even in relatively low concentrations. Alternative methods that use plants to remove pollutants from contaminated water, soil and air, can be named as phytoremediation. This term refers to the diverse complex of technologies based on the use of natural or genetically created plants for the purpose of removal of pollutants from the environment or their transformation into nontoxic forms. Indian shoot is just one of the plants that have been used recently in constructed aquatic ecosystems. This plant has experimentally been proved to be very tolerant to the absence of nutrients, and able to produce large amounts of biomass. In the water it develops a very thick strong fibrous root system with a large area for the adoption of heavy metals. It is highly tolerant to the presence of lead and is able to absorb and store it in the root and rhizome due to low translocation to aboveground parts.

The Cr (VI) reducing capacity of bacteria has been investigated in many different soils and waters but little or no information is available from soils originating from bauxite mine areas. From soil, mud and rhizospheres of the floating aquatic plant Potamogeton natans L. and the terrestrial plant Carduus acanthoides L., the Cr content was determined and the microbial populations were sampled. The highest total chromium concentration (204.6 mgkg(-1)) was found in the rhizosphere of C. acanthoides. To determine the numbers and percentages of chromate-resistant bacteria, the autochthonous microbial populations were subjected to different Cr (VI) concentrations (40, 100, 300 and 1000 mM as K2Cr2O7). At 1000 mM Cr (VI) in the medium, about 25% of bacteria from soil and 45% of bacteria from the rhizospheres were resistant. Of 34 bacterial isolates, within 24 h, only Bacillus stearothermophilus 12 ms, Pseudomonas sp. 12 bk3 and Serratia fonticola 7 be were able to reduce 50 mu M Cr (VI). Using prolonged 72 h incubation, they were able to reduce 500 mu M Cr (VI) concentrations added to the medium. These chromate-resistant bacteria isolated from rhizosphere of plants growing in bauxite mine soil have great potential for bioremediation of Cr (VI)-polluted wastes.

Oxidative stress is one aspect of metal toxicity. Zinc, although unable to perform univalent oxido-reduction reactions, can induce the oxidative damage of cellular components and alter antioxidative systems. Verbascum thapsus L. plants that were grown hydroponically were exposed to 1 and 5 mM Zn2+. Reactive oxygen species (ROS) accumulation was demonstrated by the fluorescent probe H(2)DCFDA and EPR measurements. The extent of zinc-induced oxidative damage was assessed by measuring the level of protein carbonylation. Activities and isoform profiles of some antioxidant enzymes and the changes in ascorbate and total phenolic contents of leaves and roots were determined. Stunted growth because of zinc accumulation, preferentially in the roots, was accompanied by H2O2 production in the leaf and root apoplasts. Increased EPR signals of the endogenous oxidant quinhydrone, center dot CH3 and center dot OH, were found in the cell walls of zinc-treated plants. The activities of the antioxidative enzymes ascorbate peroxidase (APX) (EC 1.11.1.11), soluble superoxide dismutase (SOD) (EC 1.15.1.1), peroxidase (POD), (EC 1.11.1.7) and monodehydroascorbate reductase (EC 1.6.5.4) were increased; those of glutathione reductase (EC 1.6.4.2), dehydroascorbate reductase (EC 1.8.5.1) and ascorbate oxidase (AAO) (EC 1.10.3.3) were decreased with zinc treatment. Zinc induced a cell-wall-bound SOD isoform in both organs. Leaves accumulated more ascorbate and phenolics in comparison to roots. We propose a mechanism for zinc-promoted oxidative stress in V. thapsus L. through the generation of charge transfer complexes and quinhydrone because of phenoxyl radical stabilisation by Zn2+ in the cell wall. Our results suggest that the SOD and APX responses are mediated by ROS accumulation in the apoplast. The importance of the POD/Phe/AA (ascorbic acid) scavenging system in the apoplast is also discussed.

The paper presents the results of the laboratory studies of the effects of two types of fungicides (Benfungin WP and Kaptan FL) on the growth rate of the mycelium of the following species of mycorrhizal fungi: Suillus luteus (L. ex Fr.) S. F. Gray, Suillus bovinus (L.ex Fr) Roussels, Suillus granulatus (L. ex Fr.)O. Kuntze, Paxillus involutus (Batsch ex fr.), Hebeloma spp., Amanita muscaria (L. ex Fr.) Hook. The observed fungicides were used in two concentrations - Benfungin WP in 0.04 and 0.06% concentrations and Kaptan FL in 0.2 and 0.3% concentrations. Benfungin had no effect on the growth of mycelium of Hebeloma spp., whereas in the direct contact in both concentrations it affected all other fungi, by stopping the growth of the mycelium. Kaptan FL had the similar effect in both concetrations, by stopping the growth of mycelium of Hebeloma spp., A. muscaria, P. involutus and S. luteus. It had no effect on the growth of mycelium of S. bovinus and S. garnulatus.

Pontic shad (Alosa immaculata Bennet 1835) is an anadromous species that lives in the heavily polluted north-western part of the Black Sea and migrates into the Danube River to spawn To assess their heavy metal contamination levels, samples of Politic shad were collected at 863 river kilometre of the Danube River Muscle, liver and gill samples were prepared using microwave digestion. and the analysis of Al, As, Cd, Cu, B. Ba. Fe, Mg. Sr. Zn. Li, Co, Cr. Mn. Mo, Ni and Pb was performed with inductively-coupled plasma-optic emission spectroscopy (ICP-OES). Significant differences in concentrations of analyzed elements were observed among different tissues, as well as between the genders Al, Sr, Ba. Mg, and Li had the highest concentrations in gills, while Cd. Cu, Zn. Fe and B were highest in the liver While the muscle had the lowest concentrations of most of the analyzed elements, it had the highest concentration of As. This study has revealed that the concentrations of Cd and As in Politic shad muscle tissue were above the maximum acceptable concentrations for human consumption, thus precautions need to be taken in order to prevent future heavy metal contamination

The effect of land use on group and fractional composition of humus was examined in 13 rendzina profiles under forests, 12 profiles under grassland and 8 profiles under arable fields in different parts of Serbia where rendzinas are typically found. The difference regarding land use of rendzina soils (depending on cultural practices or absence of any, and different amounts and quality of plant residues) under forest, grassland or arable fields had a highly significant statistical effect on humus group composition and the fractional composition of humic and fulvic acids. Human activities have brought about some positive changes regarding humus composition by promoting its stable component in rendzinas under grassland and arable fields, which is not the case in forest rendzina. The conversion of forests into grasslands and arable fields did not significantly affect the type of humus in rendzina soils, which remained characteristic of that soil type., Uticaj načina korišćenja zemljišta na grupni i frakcioni sastav humusa u rendzinama Srbije ispitivan je na 13 profila rendzine pod šumom (23 uzoraka), 12 pod travnjakom (18 uzoraka) i 8 pod njivom (16 uzoraka). Iz A horizonta uzet je jedan ili dva uzorka, zavisno od dubine, i po jedan uzorak iz prelaznog AC horizonta, u profilima koji su imali razvijen AC horizont. Razlike u načinu korišćenja zemljišta (primena ili odsustvo obrade i razlike u količini i kvalitetu biljnih ostataka) u rendzinama pod šumom, travom i njivom, statistički su značajno uticale na: grupni sastav humusa (značajno su bogatije fulvo kiselinama šumske nego rendzine pod travom, a rendzine pod travom sadrže značajno više humina nego šumske), frakcioni sastav huminskih kiselina (šumske rendzine sadrže značajno više frakcije 1 slobodnih huminskih kiselina i vezanih s mobilnim R2O3 nego rendzine pod travom i njivom) i frakcionom sastav fulvo kiselina (šumske rendzine sadrže značajno više frakcije 3 fulvo kiselina vezanih s huminskim kiselinama 3 u odnosu na njivske rendzine). Čovekova aktivnost dovela je do pozitivnih promena u sastavu humusa u pravcu povećanja stabilnog dela humusa u rendzinama pod travnjacima i njivama u poređenju sa šumskim rednzinama. Pretvaranje šuma u travnjake i njive nije značajno uticalo na tip humusa rendzina u Srbiji, koji je, kao što je poznato, a ovim istraživanjima potvrđeno, karakteristika tipa zemljišta.

Contamination of groundwater by methyl tertiary butyl ether (MTBE), that is detected in wastewater of petrochemical industry, is an increasing problem to water supply companies. The subjects of this research were the methods of photolytic, photocatalytic and microbiological degradation of methyl tertiary butyl ether (MTBE) dissolved in wastewaters. The effects of concentrated solar radiation simulated with sodium lamp (SONT UV 400) have been investigated in laboratory experiments. Our result indicated that bacteria Pseudomonas strain CY, isolated from the kerosene, and added alone, was able to gradually degrade MTBE and to decrease its concentration for 93.6% in 12 h. However, the percentage of photolytic degradation decrease in only 4 h was 99.2%. By adding Pseudomonas strain CY after 4 h of light treatment, the degradation was enhanced to 99.55% in additional 5 h. The photocatalytic process was performed in slurry-catalyst reactor with different concentrations of TiO2 catalyst: 5, 0.5 and 0.25 g/L. The MTBE degradation producing carbon dioxide reached 91% in only 150 min, when 5 g/L of catalyst was used.

Data on humus group and fractional composition in rendzina soils in Serbia acquired by the method of Pnomarieva and Plotnikova (PONOMAREVA and PLOTNIKOVA, 1968) are presented. The sites investigated in this study included: hillsides of Mt. Fruška Gora in Vojvodina; Topola and Aranđelovac environs in central Serbia; Jablanica basin and areas around Lajkovac and Valjevo in western Serbia; Sjenica-Pešter plateau in south-western Serbia; Negotin environs in eastern Serbia; and a stretch from Niš to Pirot in south-eastern Serbia. Humus was identified as belonging to the fulvate-humate type, and humification degree as medium or high. Fractional composition of humic acids is dominated by humic acids bound to Ca2+ (2), followed by those bound to clay and stable R2O3 (3), while free humic acids and those bound to mobile R2O3 (1) were found least represented. In the fractional composition of fulvic acids, the fraction bound to humic acids 2 was predominating, followed by fulvic acids bound to humic acids 3. Fulvic acids bound to humic acids 1 were found to be far less frequent, and the least so were free fulvic acids and those bound to mobile R2O3. A predomination of stable humus and the fulvate-humate humus type are the main characteristics of rendzina soils in Serbia., U ovom radu prikadani su podaci o grupnom i frakcionom sastavu humusa u rendzinama Srbije dobijeni metodom Pnomarjeve and Plotnjikove (PONOMAREVA and PLOTNIKOVA, 1968). Istraživanjima su obuhvaćena područja karakteristična za ovaj tip zemljišta: obronci Fuške gore u Vojvodini; okolina Topole i Aranđelovca u centralnoj Srbiji; sliv reke Jablanice i okolina Lajkovca i Valjeva u zapadnoj Srbiji; Sjeničko Pešterska visoravan u jugo-zapadnoj Srbiji, okolina Negotina u istočnoj Srbiji i potez Niš-Pirot u jugo-istočnoj Srbiji. Sadržaj huminskih kiselina varira u širokom intervalu, od 10.00 do 35.71%, a u prošeku iznosi 26.27%. Stepen humificiranosti Amo i Ap horizonata većine profila je srednji, a manjeg broja profila visok, a stepen humificiranosti AC horizonata je uglavnom srednji, u manjem broju profila nizak. Sadržaj fulvo kiselina varira u širokom intervalu od 26.40 do 55.09%, u prošeku iznosi 37.08%. Odnos huminskih i fulvo kiselina u Amo ili Ap horizontima varira od 0.38 do 1.06, a u AC horizontima od 0.25 do 0.76. U većini ispitivanih profila rendzina Srbije humus je fulvatno-humatnog tipa. Sadržaj nerastvornog ostatka je dosta visok, varira u širokom intervalu, od 16.34 do 51.58%, a u prošeku iznosi 36.95%. U frakcionom sastavu huminskih kiselina ispitivanih rendzina Srbije preovlađuje frakcija 2 - vezana sa Ca2+ (7.52-24.49%, u prošeku 13.78%); sledi frakcija 3 huminskih kiselina vezanih sa glinom i stabilnim R2O3 (l .89-15.82%, u prošeku 10.01%), a najmanje je zastupljena frakcija l huminskih kiselina slobodnih i vezanih sa mobilnim R2O3 (0.00-6.93%, u prošeku 2.19%). U frakcionom sastavu fulvo kiselina istraživanih rendzina Srbije najzastupljenija je (7.52-24.49%, u prošeku 13.78%) frakcija 2 fulvo kiselina -vezanih sa huminskim kiselinama 2, nešto manje je zastupljena (6.31-18.18%, u prošeku 12.37%) frakcija 3 fulvo kiselina - vezanih sa frakcijom 3 huminskim kiselinama. Udeo frakcije l fulvo kiselina - vezanih sa frakcijom l slobodnih huminskih kiselina je zn

The aim of our investigation was to establish the degree of atrazine resistance in plants of Chenopodium album L. population from Serbia and resistance population from Great Britain. Seeds used in experiments were collected from the corn grown areas treated with atrazine for over ten consecutive years (Surčin and Veliki Crljeni), while the control seeds were collected from untreated areas nearby Belgrade (Belgrade). As a referent population resistant seeds of Chenopodium album L. from Great Britain were used. Plants in fully emerged third leves, from all population, were sprayed with different doses (2, 4 and 8 kg ha-1) of atrazine (Gesaprim, 90% a.i. atrazine). As a non destructive methods we used SPAD-meter for measuring chlorophyll content and fluorometer for chlorophyll a fluorescence which is expressed as ratio between variable (Fv) and maximal (Fm) chlorophyll fluorescence. Both parameters were measured at the same leaf before and 1, 2, 3, 4 and 5 days after atrazine treatments. Results shown that the most sensitive method is by using method of chlorophyll fluorescence. SPAD-meter is not adequate for distinguishing triazine resistant and susceptible plants. In populations of Chenopodium album L.- collected from Serbia (Veliki Crljeni, Surcin and Belgrade) atrazine resistance is not confirmed.