Genetic Variability of Acetolactate Synthase (ALS) Sequence in Centaurea cyanus Plants Resistant and Susceptible to Tribenuron-Methyl

Centaurea cyanus, belonging to the Asteraceae family, is an arable weed species encountered mainly in fields with cereals, sugar beet, and maize. The high genetic variability of C. cyanus has been recently reported; however, little is known about its sequence variability in the context of its herbicide resistance. C. cyanus resistance was found mainly against acetolactate synthase (ALS) inhibitors, but no ALS sequence information concerning the herbicide resistance mechanism has been published yet. The aim of this study was to determine the ALS sequences for biotypes susceptible and resistant to tribenuron-methyl in order to identify mutations that may be associated with the resistance emergence. DNA isolation from susceptible and resistant plants was followed by PCR amplification and ALS sequencing. As a result, different lengths of DNA products were obtained. Moreover, both nucleotide and amino acid sequence analysis revealed high sequence variability within one plant as well as between plants from the same biotype. In a few resistant plants, four changes in the amino acid sequence were identified in comparison to those in the susceptible ones. However, these preliminary studies require further investigation toward confirming the significance of these mutations in herbicide resistance development. This study provides preliminary information contributing to the research on the C. cyanus target-site resistance mechanism.

Herbicide Resistance of Centaurea cyanus L. in Poland in the Context of Its Management

Cornflower (Centaurea cyanus L.), one of the main weeds found among winter crops in Poland, has developed herbicide resistance (HR) to acetolactate synthase (ALS) herbicides, a finding first reported in 2006, and in recent years, farmers have been complaining about inadequate chemical control of this weed. This study aimed to characterise the current state of cornflower HR to ALS inhibitors and synthetic auxins in Poland and the agricultural practices in fields with herbicide-resistant populations. From 2017 to 2020, 159 seed samples together with the field history were collected across the country and biological tests performed in glasshouses. This revealed that 47 populations of C. cyanus were cross-resistant to both tribenuron and florasulam, 28 and 8 populations were single resistant to tribenuron and florasulam, respectively, and 3 populations had developed multiple resistance to both ALS inhibitors and synthetic auxins, i.e., 2,4-D and dicamba. Resistant populations were found mostly frequent in northern Poland, but also in the eastern and western parts of the country. Based on a survey of farmers, the resistant populations were found in winter crops regardless of the tillage system (77% of fields with HR cornflower were mouldboard ploughed). Based on the proposed population treatment (PT) index showing the frequency of herbicide use during three consecutive seasons on farms with HR cornflower, the average PT for all the surveyed farms was 5.4. The highest PT of 7.4 was found in the province of Warmia-Masuria in northern Poland.

Zinc Oxide Nanoparticles Preparation for Pd2+ Ions Adsorption From Aqueous Wastewaters: A Green Technique

ZnO nanoparticles (NPs) were easily synthesized using zinc nitrate through centaurea cyanus extract (as a reducing agent) at ambient conditions. XRD results demonstrated that ZnO NPs have a high-crystalline hexagonal structure with an average size of 48 nm in diameter. FT-IR spectral analysis indicated an active contribution of centaurea cyanus-derived biomolecules in zinc ions bioreduction. According to SEM analysis, ZnO NPs were properly dispersed and had a hexagonal shape. Batch experiments were performed to investigate the impact of several process parameters such as initial pH of solution, adsorption dosage, Pd2+ ions initial concentration and contact time on the Pd2+ ions adsorption from the solution. The Freundlich isothermal model could excellently legitimize a multilayer adsorption. Furthermore, the adsorption process followed a pseudo-second-order reaction kinetic. The maximum adsorption (99.24%) was experimentally found at pH of 5.5, adsorption dosage of 1.63 g.L-1, Pd2+ ions initial concentration of 77.5 mg.L-1 and contact time of 91.25 min.

Genetic Variability of Acetolactate Synthase (ALS) Sequence in Centaurea Cyanus Plants Resistant and Susceptible to Tribenuron-methyl

Centaurea cyanus, belonging to the Asteraceae family, is an arable weed species being encountered mainly in the fields with cereals, sugar beet, and corn. C. cyanus high genetic variability has recently been reported, however, little is known about sequence variability in the context of herbicide resistance. C. cyanus resistance was found mainly against acetolactate inhibitors (ALS) inhibitors, but no ALS sequence information concerning herbicide resistance mechanism has been published yet. Therefore, the aim of this study was to determine ALS sequences for biotypes susceptible and resistant to tribenuron-methyl in order to identify possible mutations conferring the resistance. DNA isolation from susceptible and resistant plants was followed by PCR amplification and sequencing of ALS sequence. As a result different lengths of DNA products were obtained. Moreover, both nucleotide and amino acid sequence analysis revealed high sequence variability within one plant as well as between plants from the same biotype. In a few resistant plants, six changes in amino acid sequence were identified in comparison to susceptible ones. However, these preliminary studies require further investigation toward confirming the significance of these mutations in herbicide resistance development. This study provides the first attempt in the research on C. cyanus target-site resistance mechanism.

Comparative palynomorphological study of two species in the valley of Zagoria, Gjirokastra, Albania

In this study there are demonstrated for the first time in albanian literature the palynomorphologic characteristics of two types of plants (Centaurea epirota and Viola epirota), collected in Zagoria valley, Gjirokastra region, in Albania. To carry out the study, light microscopy was used and it was concluded that the pollen grains of Centaurea epirota were 3 colporate, isopolar, with radial symmetry. In the polar view, the pollen grains have a circular triangular shape while in the equatorial view they have a compressed oval shape. Exine appeared scabrate. Viola epirota consisted of 3-4 colporate, sometimes even 5 colporate pollen grains. In the polar view, the pollen grains had a circular shape of 3 or 4 angles, sometimes even 5 angles while in the equatorial view they had an elliptical shape. Exine appeared granulate. To see the impact of ecological factor and the method of laboratory processing of pollen grains, the size of the new species studied was compared with the size of the pollen grains of Centaurea cyanus and Viola alba, Viola odorata and Viola arvensis, taken from the native literature.

Comparative Assessment of the Phytochemical Composition and Biological Activity of Extracts of Flowering Plants of Centaurea cyanus L., Centaurea jacea L., and Centaurea scabiosa L.

The data on the phytochemical composition and biological activity for flowering plant extracts of the genus Centaurea (Knapweed)—cornflower (Centaurea cyanus L.), brown knapweed (Centaurea jacea L.), and greater knapweed (Centaurea scabiosa L.), which are typical representatives of the flora in the middle belt of the Russian Federation, were obtained. For the first time, biologically active substances such as pyranone, coumaran (2,3-dihydrobenzofuran), and 5-hydroxymethylfurfural were identified in ethanol and methanol extracts of Centaurea scabiosa L. by gas chromatography–mass spectrometry. Catechol and α-amyrin were the major components of the ethanol extract from Centaurea cyanus L., and flavone was the major component of Centaurea jacea L. flower extract. The greatest antimicrobial activity against phytopathogens was detected in Centaurea scabiosa L. when extracting freshly harvested flower biomass with methyl tert-butyl ether at room temperature: the minimum inhibitory concentrations were 60–120 µg/mL, the minimum fungicidal concentration was 120 µg/mL, and the minimum bactericidal concentration was 250 µg/mL. The low antioxidant activity of the studied plant extracts was established using the maximum values of Centaurea jacea L. Ethanol extract of Centaurea cyanus L. flowers had low antimicrobial and antioxidant activity. The extracts showed no phytotoxicity to garden cress germination but inhibited the growth of juvenile plants, especially roots. The greatest phytotoxic effect was revealed with methyl tert-butyl ether, where the depression of growth indicators was 35% or more.

Synthesis and characterization of herbicidal ionic liquids based on (4-chloro-2-methylphenoxy)acetate and phenoxyethylammonium

Ten ionic liquids containing the (4-chloro-2-methylphenoxy)acetate (MCPA) anion and domiphen derived phenoxyethylammonium cation were synthesized. The obtained compounds differed in terms of the substitution of the phenoxyethylammonium group in the ring (the presence of a methyl group in the meta or para positions and the presence of chlorine in the para position) as well as the length of the alkyl chain (from hexyl to tetradecyl). The basic physicochemical properties of the obtained ionic liquids (solubility and thermal stability) were characterized and their structures were confirmed. The herbicidal activity of the compounds was tested under greenhouse conditions using cornflower (Centaurea cyanus L.) as the test plant.

ПОСІВНІ ЯКОСТІ НАСІННЯ ЛІКАРСЬКИХ РОСЛИН ЗАЛЕЖНО ВІД ЇХ СТРАТИФІКАЦІЇ

Досліджено посівні якості насіння лікарських рослин: калачиків лісових (Malva sylvestris L.), ехіна-цеї пурпурової (Echinacea purpurea (L. Moench.), ехінацеї блідої (Echinacea pallida (Nutt.) Nutt.), звіробою звичайного (Hypericum perforatum L.) та волошки синьої (Centaurea cyanus L.) залежно від дії стратифікації при температурі +3 0С протягом 15, 30 та 45 діб. Контролем слугувало насіння, яке зберігалося такий же термін за температури +20 0С. У насіння калачиків лісових після стратифі-кації тривалістю 15 діб енергія проростання суттєво зростала на 65,6 %, а лабораторна схожість – на 46 % відносно контролю; більш тривале витримування насіння було малоефективним. У ехінацеї пурпурової стратифікація суттєво збільшила вказані показники. Енергія проростання зросла на 9–20 % і становила 78–82 %, а енергія проростання – на 10,2–13,4 % і досягла 93 % після 45 діб стратифікації. Внаслідок стратифікації насіння ехінацеї блідої енергія проростання через 15 діб зросла в 1,3 раза (до 72 %), через 30 діб – в 1,36 раза (до 79 %), а через 1,5 місяця – в 1,26 раза (до 82 %) відносно контролю. Такі закономірності простежувалися і при визначенні лабораторної схо-жості. Наші дослідження насіння волошки синьої свідчать, що стратифікація протягом 15 діб не призвела до суттєвого збільшення як енергії проростання, так і лабораторної схожості. Більш тривалий термін дії понижених температур призвів до суттєвого збільшення енергії проростання на 7,5‒10,0 %, і недостовірно вплинув на лабораторну схожість (+3,4% – +5,7 % до контролю). Вивчення впливу стратифікації на насіння звіробою свідчить, що після 15–30 діб стратифікації енергія проростання збільшилась на 2–3 % до контролю, а через 45 діб – на 13 %. Лабораторна схожість зросла в 1,05; 1,09; 1,18 раза відповідно, що свідчить про ефективність витримування на-сіння звіробою 1,5 місяця при понижених температурах. Зроблено висновок про ефективність за-стосування стратифікації насіння лікарських культур.

Ecological and biological features of annual ornamental plants under pre-winter sowing in a continental climate

The paper presents the results of a long-term study of biological features of annual ornamental plants species belonging to the ecological group of therophytes included in the bioresource collection USU 44053 and capable of creating a high ornamental effect after pre-winter sowing in the ground. The hydrothermal conditions of the wintering and subsequent vegetation periods are characterized. The accumulation of snow necessary for successful overwintering of seeds is analyzed. Comparative phenospectra of species under different cultivation methods are presented, with an emphasis on achieving the fruiting phase. Examples of naturalization of these species are given, which characterize their high adaptive potential. The most promising species for use in the urbanized environment of the Siberian region are: Amaranthus caudatus L., A. paniculatus L., Brachycome iberidifolia Benth., Calendula officinalis L., Centaurea cyanus L., Clarkia unguiculata Lindl., C. pulchella Pursh., Eschscholzia californica Cham., E. pulchella Cham., Gilia achilleifolia Benth., G. capitata Sims, G. tricolor Benth., Gypsophila elegans M. Bieb., Helichrysum bracteatum (Vent.) Andrews, Iberis umbellata L., Layia elegans Torr. A. Gray, Rudbeckia hirta L., Salpiglossis sinuata Ruiz Pav., Schizanthus pinnatus Ruiz Pav., Vaccaria hispanica (Mill.) Rauschert.