Effect of nicosulfuron on the populations of invasive weedy sunflower

Weedy sunflower Helianthus annuus L. (WS) can become troublesome for cultivated sunflower given their genetic similarity which allows gene flow from weed-to-crop and from crop-to-weed. Also, it causes yield losses in different spring-sown crops. Despite this, there is still no data about its response to herbicides. Field experiments were conducted to quantify the effects of nicosulfuron on WS populations. Plants of three populations (R1-WS and R2-WS = presumably resistant and S-WS = susceptible) were treated with 40 g nicosulfuron ha-1 at the 2–4 true-leaf growth stage. Vegetative parameters (plant height, fresh weight, leaf area) and relative chlorophyll content (RCC) were measured 30 days after herbicide application. Generative parameters (number of heads plant-1, head diameter, number of seeds plant-1) were measured at maturity. After harvesting, seed germination of collected seeds was studied in Petri dishes at 25°C.Nicosulfuron was found to have a significant effect on vegetative and generative production of WS plants. The effect on RCC and postharvest seed germination was not so prominent. All this effects depended on the population, which is probably a result of different history of herbicide application and possible development of resistance in the populations R1-WS and R2-WS.Die Auswirkung von Nicosulfuron auf invasive Unkraut-SonnenblumenbeständeIn Anbetracht der genetischen Ähnlichkeit zwischen der Kulturpflanze und seinem zugehörigen Unkraut, die einen Genfluss in beiden Richtungen ermöglicht, ist es zu erwarten, dass auch die Unkraut-Sonnenblume, Helianthus annuus (WS) eine bedeutende Entwicklungsstörung bei der Ackersonnenblume hervorrufen und genauso Ertragsverluste bei anderen Sommerungen verursachen kann.Angesichts der fehlenden Daten bezüglich der Herbizidreaktion des obengenannten Unkrauts wurden entsprechende Felduntersuchungen durchgeführt, mit dem Ziel die Auswirkungen von Nicosulfuron auf WSPopulationen quantitativ zu bestimmen. Drei unterschiedliche Pflanzenbestände (R1-WS und R2-WS = vermutlich resistent, und S-WS = anfällig) wurden mit 40 g Nicosulfuron/ha, jeweils auf das zweite Blattpaare behandelt. Vegetative Parameter (Pflanzengröße, Frischmasse, Blattfläche) und relativer Chlorophyllgehalt (RCC) wurden 30 Tage nach dem Herbizideinsatz gemessen. Generative Parameter (Anzahl der Pflanzenköpfe, Kopfdurchmesser, Anzahl der Pflanzensamen) wurden im reifen Zustand gemessen. Nach der Ernte, wurde noch die Keimung der gesammelten Samen in Petrischalen mit einer Temperatur von 25 °C genauer beobachtet.Die Ergebnisse deuteten darauf hin, dass Nicosulfuron eine erhebliche Auswirkung auf vegetative so wie auch auf generative Produktion von WS-Pflanzen hat. Die Auswirkung auf RCC und Keimung durch Ernte gewonnener Samen zeigte sich jedoch nicht in dem gleichen Maße auffällig. Alle Effekte standen im Zusammenhang mit den Pflanzenpopulationen, was wahrscheinlich eine Folge vom andersartigen Verlauf der früheren Herbizidanwendungen, und vermutlicher Resistenzentwicklung in R1-WS und R2-WS Populationen ist

Populaciona varijabilnost vrste Polygonum aviculare L.

As Polygonum aviculare L. is characterized by exceptional polymorphism, 10 populations of this species were subjected to relevant morpho-anatomical investigation for a more detailed taxonomic determination. The following morphological parameters were measured: stem length, internode length, leaf length and width, and leaf area. To analyse the basic differences in leaf anatomy, the following parameters were measured: upper epidermis height of leaf, mesophyll thickness and lower epidermis height of leaf. All data acquired in this investigation were processed by SPSS 8.0 software, and t-test was used to determine the significance of the differences found among the populations analysed, while their differentiation was done using canonical discriminant analysis (CDA) and cluster analysis. Morphological differences among the analysed populations were found more evident than the anatomical. Leaf length and width, leaf area, internode length and leaf thickness were the most discriminating parameters for population differentiation.Polygonum aviculare L. se odlikuje izuzetno velikim polimorfizmom i radi preciznije taksonomske determinacije urađena su relevantna morfo-anatomska ispitivanja 10 populacija ove vrste. Od morfoloških pokazatelja mereni su sledeć i parametri: dužina stabla, dužina internodije, dužina, širina lista i površina lista. Za definisanje osnovnih anatomskih razlika listova analizirani su sledeći parametri: visina epidermalnih ćelija lica lista, debljina mezofila i visina epidermalnih ćelija naličja lista. Svi dobijeni rezultati su obrađeni u programskom paketu SPSS 8.0, pri čemu je značajnost razlika između analiziranih populacija određena t-testom, dok je njihovo razdvajanje urađeno pomoću kanonične diskriminantne analize (CDA) i klaster analize (Cluster). Razlike između ispitivanih populacija bile su izrazitije na morfološkom nego na anatomskom nivou. Naime, parametri koji su najviše uticali na razdvajanje populacija su: dužina i širina lista, površina lista, dužina internodije i debljina lista

Rezerve semena korovskih biljaka u konvencionalnom sistemu gajenja kukuruza

Crop rotation and tillage systems are the most important agrotechical measures that interaction with the suppression of weeds and affect the size and composition of the weed seed bank and are in direct correlation with their content in the soil. Knowing seed bank, as well as monitoring the dynamics of the appearance of weed species, constitute the basis for planning and implementation of measures for their effective suppression. The paper presents the evaluation of weed infestation of maize grown in monoculture, 2-year crop rotation (maize, wheat) and 3-year crop rotation (maize, soybeans, wheat) on long-term experiment "Crop Rotation" of the Institute of Field and Vegetable Crops in Novi Sad. Soil samples, taken after the harvest of corn from a depth of 0–15 cm, 15–30 cm and 30–40 cm, were used for the analysis of weed seed bank. By applying the methods of physical extraction, soil samples were irrigated through a system of sieves of different sizes, and by using binoculars and a guide for the determination, a separate determination of seeds was made. The data obtained made it possible to view the number of seeds present in the soil, as well as the vertical distribution of weed species in both arable and subsoil layer.Plodored i sistemi obrade zemljišta spadaju u najvažnije agrotehničke mere koje u interakciji sa suzbijanjem korova utiču na veličinu i sastav rezervi semena korovskih biljaka i u direktnoj su korelaciji sa njihovim sadržajem u zemljištu. Poznavanje rezervi semena, kao i praćenje dinamike pojave korovskih vrsta predstavljaju osnovu u planiranju i sprovođenju mera za njihovo efikasno suzbijanje. U radu je prikazana procena zakorovljenosti kukuruza gajenog u monokulturi, dvopoljnom (kukuruz, pšenica) i tropoljnom plodoredu (kukuruz, soja, pšenica) na višegodišnjem stacionarnom ogledu „Plodoredi“ Instituta za ratarstvo i povrtarstvo u Novom Sadu. Uzorci zemljišta uzeti nakon žetve kukuruza sa dubine 0–15 cm, 15–30 cm i 30–40 cm poslužili su za analizu rezervi semena korovskih biljaka. Primenom metode fizičke ekstrakcije, zemljišni uzorci su ispirani kroz sistem sita različite finoće, a korišćenjem binokulara i priručnika za determinaciju izvršena je determinacija odvojenog semena. Dobijeni podaci su omogućili da se prikaže brojnost prisutnog semena u zemljištu, kao i vertikalna distribucija semena korovskih vrsta kako u oraničinom, tako i podoraničnom sloju

Sphaerospora molnari (myxozoa) kod šaranske mlađi

Sferosporidioza škrga je obolenje riba izazvano parazitom Sphaerospora molnari koji napada škrge i kožu. Prvo pojavljivanje sferosporidioze škrga kod šaranskih mladunaca utvrđeno je u Mađarskoj još 1972, zatim u Češkoj i Poljskoj, dok je kod nas obolenje prisutno od sredine osamdesetih godina prošlog veka. Molnar, koji je prvi је izučavao patogeni efekat ovog uzročnika, najpre ga je identifikovao kao Sphaerospora carassi. Češki istraživači Lom et Dycova detektovali su uzročnika sferosporidioze škrga iz škržnog materijala obolelih mladunaca šarana pomoću histološke sekcije tkiva i predložili da se parazitu da ime Sphaerospora molnari. Ovo obolenje je dosta često kod mladunaca ribnjačkog šarana i amura, pri čemu intenzitet infestacije može dostići čak i do 100%. Cilj ovog rada jeste da se utvrdi prisustvo obolenja izazvanog parazitom Sphaerospora molnari i da se isprate kliničke i patohistološke promene kod infestiranih mladunaca šarana. Istraživanja su sprovedena na 18 šaranskih ribnjaka u Srbiji, od 2008. do 2012. godine, a u sklopu sistemskog monitoringa najznačajnijih protozooza šarana. Mladunci šarana pregledani su tokom čitavog vegetacionog perioda. Praćene su kliničke promene, i uzimani su uzorci za nativnu mikroskopiju koja je rađena pomoću svetlosnog mikroskopa. Od inficiranih jedinki uzimano je tkivo škrga za patohistološku analizu koja je sprovedena klasičnom metodologijom, fiksiranjem u 10% formalinu, sečenjem 5 μm velikih isečaka koji su kalupljeni u parafin i bojenjem isečaka pomoću H&E. Prisustvo S. molnari ustanovljeno je kod mladunaca šarana od 20 dana do 3 meseca starosti. Na škrgama su bili prisutni razvojni stadijumi i zrele spore što se moglo uočiti na stratifikovanom epitelu škržnih filamenata. Spore su invadirale epitel i formirale velike klastere. Akumulacija razvojnih stadijuma i zrelih spora bila je prisutna je i kod dvostrukog sloja epitelnih ćelija koje pokrivaju sekundarne lamele, i to najčešće između unutrašnjeg i spoljašnjeg omotača izazivajući tako distenziju tkiva. Zaražene lamele podležu nekrozi, što dovodi do kretanja spora prema spolja. Veličina spora iznosila je 10 x 10 μm. Klinički, obolenje se manifestovalo pojavom beličastih depozita na škrgama kao posledica agregacije parazita na njima, pri čemu paraziti mogu da zauzmu i do 80% površine slojevitog epitela, prekrivajući pločice i lukove škrga. Pritisak parazita koji se razmnožavaju je takav da vrši ćelijsku deformaciju tkiva i na kraju se uočava istančanost citoplazme ćelija šktžnog epitela u obliku mreže. Pošto spore prekrivaju najveći deo respiratornog epitela, smanjuju otpornost organizma i stvaraju uslove za razvoj drugih uzročnika obolenja (prvenstveno trematoda), što Sphaerosporu molnari svrstava u patogene parazite. Lokalizacija, veličina spora odnosno razvojnih stadijuma S. molnari, kao i kliničke i patohistološke promene zabeležene tokom ovog istraživanja odgovaraju rezultatima koje su opisali ostali istraživači koji su se bavili ovom problematikom. Pošto ne postoji ni jedno adekvatno terapeutsko sredstvo, kontrola sferopsoridioze i dalje se bazira na pridržavanju osnovnih sanitarno–profilaktičkih mera, kao što su isušivanje objekata, izmrzavanje, mehanička obrada tla i dezinfekcija krečom

Population variability of weedy sunflower as invasive species

Three populations of weedy sunflower were investigated with the aim to assess its population variability. The following parameters were evaluated: vegetative parameters - plant height (cm), leaf lenght (cm), leaf width (cm), number of ray flowers, number of bract; generative parameters - head diametar (cm), mass of achene per head (g), number of achene per head; and achene parameters - achene lenght (µm), achene width (µm), mass of 100 achenes (g). Except that, achene morphology as indicator of population variability was studied. The studied populations significantly differed regarding to most measured parameters, while only plant height and number of ray flowers were similar in all three populations

Effect Long-Term Management System on Soil Weed Seed Bank

Long-term monoculture has a de-stroying impact on plant production, while crop rotation is known as a more eco-friendly approach as provides diversification in crop management systems, modifies intensive pressure on the agricultural ecosystem, utilizes various soil horizons, and prevents the establishment of specific pests and weeds. The aim of his research was to answer: How management system over 50 years of specific continuous crop management programs (crop rotation and fertilization) effect on weed populations? This study was conducted in the experimental site of the Institute of Field and Vegetable Crops of “Plodoredi”, Rimski Šančevi, Novi Sad, Serbia. It has been estimated three monocultures of maize, wheat and soybean, 2-year crop rotation (winter wheat-maize) with and without chemical fertilizer and 3–year crop rotation (winter wheat-soybean-maize) with and without chemical fertilizer and manure. Soil samples were taken six times from 2014 to 2017 prior to sowing and after harvesting each year. Weed seeds were extracted from soils and identified and counted by species. Mixed model analysis was used to determine the effect of the crop sequence and fertilizers on weed seed bank. To compare the strength of the treatment, it calculated the log-worth with their P-values. Upon the data of a long term experiment of crop rotation, could approve that crop rotations with more crops in the sequence are significantly effective in maintaining weed population. Therefore, will be a more sustainable crop production, chemical fertilizers would imbalance the plant population diversity and manures with high number of weed seeds have potentials to totally vanish crop rotation effects. Mixed model analysis suggests that on over 50 years of the management practices crop sequence × fertilizer interaction had the highest effect (log-worth = 64.7), followed by the triple interactions between crop sequence × fertilizer × soil depth (log-worth = 30.5). The number of seeds in soil significantly decreased from surface layer to deep soil. The crop sequence efficiency in decreasing weed seed bank was highly dependent on the fertilizer management, as with chemical fertilizer, the three years crop rotations had significantly lower seed bank, while with manure, the effect of crop rotations was eliminated

Reakcije populacija Sorghum halepense L. (Pers.) na nikosulfuron, rimsulfuron i prosulfuron+primisulfuron-metil

The effects of herbicides nicosulfuron, rimsulfuron and prosulfuron+primsulfuronmethyl on eight populations of Sorghum halepense L. (Pers.) under controlled conditions were investigated. The herbicides were applied at different rates (0x; 0,5x; 1x; 1,5x; 2x; 3x recommended application rate for field use) when plants reached the height of 20-25 cm. The parameters measured seven days after treatment were leaf surface and fresh and dry mass of plants; the obtained results were then used for ED50 calculations. The response of Sorghum halepense populations to nicosulfuron, rimsulfuron and prosulfuron+primsulfuron-methyl varied from population to population, and depending on the applied rate and the measured parameter. Resistance development was not observed in any of the populations that survived herbicide treatment before seed collecting. Only the population P2 showed somewhat decreased susceptibility to nicosulfuron, which can be regarded as an early stage of resistance development.Ispitivane su reakcije 8 populacija vrste Sorghum halepense L. (Pers.) na herbicide nikosulfuron, rimsulfuron i prosulfuron+primisulfuron-metil u kontrolisanim uslovima. Primena različitih količina (0x; 0,5x; 1x; 1,5x; 2x; 3x od količine koja je preporučena za primenu u poljskim uslovima) ovih herbicida izvedena je kada su biljke bile visine 20-25 cm. Sedam dana nakon primene herbicida mereni su sledeći parametri: površina listova, sveža i suva masa biljaka, a na osnovu dobijenih rezultata su određene ED50 vrednosti. Reakcije populacija S. halepense na nikosulfuron, rimsulfuron i prosulfuron+primisulfuronmetil su bile različite u zavisnosti od populacije, količine primene herbicida i ispitivanog parametra. Nijedna od populacija koja je pre sakupljanja semena preživela primenu navedenih herbicida nije razvila rezistentnost. Samo je kod populacije P2 potvrđena smanjena osetljivost na nikosulfuron, koja se može smatrati početkom razvoja rezistentnosti

Environmental Bovine Mastitis Pathogens: Prevalence, Antimicrobial Susceptibility, and Sensitivity to Thymus vulgaris L., Thymus serpyllum L., and Origanum vulgare L. Essential Oils

Mastitis is considered to be one of the most important diseases of dairy cows in terms of health, production, and economy. Being the most common cause of antibiotic consumption in dairy cows, treatment of this disease is one of the biggest challenges in the veterinary profession as an increasing number of pathogens develop resistance to antibiotics used in the treatment. Therefore, new alternative approaches for limiting the use of antibiotics in livestock are required. For this reason, our study aimed to investigate prevalence of environmental mastitis associated bacterial strains, as well as the sensitivity of isolated strains to different antibiotics. Additionally, the therapeutic potential of three essential oils (EOs) was tested against bovine Serratia spp. and Proteus spp. mastitis pathogens, based on their chemical composition, as well as antibacterial potential. The study was carried out on 81 milk samples collected from dairy cows with mastitis. In order to determine prevalence of S. marcescens and P. mirabilis, microbiological isolation and identification were performed. Antimicrobial susceptibility testing was performed by disk diffusion method and the microdilution method was used to determine the antibacterial activity of selected EOs. In the oregano EO, a total of 23 compounds were detected, with carvacrol as a dominant component (78.94%). A total of 26 components were present in the EO of common thyme, where thymol was the most abundant compound (46.37%). Thymol also dominated (55.11%) the wild thyme EO. All tested EOs displayed antibacterial activity against all strains to different extents, while wild and common thyme EOs were the most effective. It could be concluded that the tested EOs represent promising therapeutic candidates for effective non-antibiotic treatment of mastitis

How Do Long Term Crop Rotations Influence Weed Populations: Exploring the Impacts of More than 50 Years of Crop Management in Serbia

Crop rotation is known as an eco-friendlier approach, as provides diversification in crop management systems, modifies intensive pressure on the agricultural ecosystem, utilizes various soil horizons, and prevents the establishment of specific pests and weeds. We set out here a study on the farms that have been managed over 50 years of specific continuous crop management programs. The experimental treatments were in a different management system: monoculture of maize, winter wheat, and soybean, 2-year crop rotation (winter wheat–maize) with and without chemical fertilizer, and 3-year crop rotation (winter wheat–soybean–maize) with and without chemical fertilizer and manure. We took soil samples six times from 2014 to 2017 prior to sowing and after harvesting each year. Weed seeds were extracted from soils and identified and counted by species. We, upon the data of a long term experiment of crop rotation, could conclude that crop rotations with more crops in the sequence are significantly effective in maintaining weed populations, a low-input crop production could reach a constant low population below an important damaging density, and therefore will be a more sustainable crop production while chemical fertilizers would change the soil’s chemical and structure and imbalance the plant population diversity and manures with high weed seed infestations have the potential to totally eradicate crop rotation effects, Therefore, clean manures or compost are highly recommended

Elucidation of the biosynthesis of carnosic acid and its reconstitution in yeast

Rosemary extracts containing the phenolic diterpenes carnosic acid and its derivative carnosol are approved food additives used in an increasingly wide range of products to enhance shelf-life, thanks to their high anti-oxidant activity. We describe here the elucidation of the complete biosynthetic pathway of carnosic acid and its reconstitution in yeast cells. Cytochrome P450 oxygenases (CYP76AH22-24) from Rosmarinus officinalis and Salvia fruticosa already characterized as ferruginol synthases are also able to produce 11-hydroxyferruginol. Modelling-based mutagenesis of three amino acids in the related ferruginol synthase (CYP76AH1) from S. miltiorrhiza is sufficient to convert it to a 11-hydroxyferruginol synthase (HFS). The three sequential C20 oxidations for the conversion of 11-hydroxyferruginol to carnosic acid are catalysed by the related CYP76AK6-8. The availability of the genes for the biosynthesis of carnosic acid opens opportunities for the metabolic engineering of phenolic diterpenes, a class of compounds with potent anti-oxidant, anti-inflammatory and anti-tumour activities