Weed Control in Sunflower (Helianthus annuus L.) with Soil-applied Herbicides Affected by a Prolonged and Limited rainfall

The field trials were carried out in the Bitola and Titov Veles regions during two sunflower growing seasons (2018 and 2019) to estimate a weed control in sunflower with the soil‒applied herbicides, influenced by a prolonged and limited rainfall. Polygonum aviculare L., Solanum nigrum L., Chenopodium album L., Amaranthus retroflexus L., Portulaca oleracea L., and Echinochloa crus-galli (L.) P. Beauv. were the most dominant weeds in both regions. The efficacy of PRE-em herbicides varied among the weed species, treatments, periods of efficacy estimation, regions, and years. The overall performances of the PRE-em herbicides were correlated with weather and soil conditions. The inconsistent weather patterns between the two years of the study likely influenced the weed control. All weeds in 2018 in the Bitola region were poorly controlled (<77% and <62%, 28 and 56 days after application, respectively) due to a higher amount of rainfall (57 mm) during the 10 days of the 1st decade after herbicide application. The herbicide efficacy has only produced a marginal control of weeds in 2019 in the Titov Veles region as well (<68% and <59%, 28 and 56 days after application, respectively), due to the drought conditions observed in this region in early spring and in mid-spring. A PREem application followed by a heavy rainfall resulted in a sunflower injury in the Bitola region in 2018, ranging from 9 to 28% across the PRE-em treatments seven days after emergence. The injuries by oxyfluorfen and dimethenamid-P were more serious (24 and 28%, respectively). The sunflower achene yields for each treatment in both regions generally reflected an overall weed control and crop injury.

Topsoil Seed Bank as Feeding Ground for Farmland Birds: A Comparative Assessment in Agricultural Habitats

The topsoil seed bank was studied in four types of agricultural bird habitats: fields with cereals, maize, clover and tilled fields of a Mediterranean plain to determine the potentially richest habitat based on food supply for the wintering farmland birds. The diversity and abundance of topsoil seeds differed between seasons but did not differ significantly between habitats. The cereal habitat was the richest in food supply for the overwintering of farmland birds. The topsoil seed bank was dominated by Chenopodium album, Polygonum aviculare and Amaranthus retroflexus. The findings of this study provide insight for low-intensity management of higher-elevation mount agricultural areas of southern Mediterranean by preserving seed-rich habitats for farmland avifauna.

Comparative Study of the Pharmacological Properties and Biological Effects of Polygonum aviculare L. herba Extract-Entrapped Liposomes versus Quercetin-Entrapped Liposomes on Doxorubicin-Induced Toxicity on HUVECs

This study aimed to evaluate the comparative biological effects of Polygonum aviculare L. herba (PAH) extract and quercetin-entrapped liposomes on doxorubicin (Doxo)-induced toxicity in HUVECs. HUVECs were treated with two formulations of liposomes loaded with PAH extract (L5 and L6) and two formulations of liposomes loaded with quercetin (L3 prepared with phosphatidylcholine and L4 prepared with phosphatidylserine). The results obtained with atomic force microscopy, zeta potential and entrapment liposome efficiency confirmed the interactions of the liposomes with PAH or free quercetin and a controlled release of flavonoids entrapped in all the liposomes. Doxo decreased the cell viability and induced oxidative stress, inflammation, DNA lesions and apoptosis in parallel with the activation of Nrf2 and NF-kB. Free quercetin, L3 and L4 inhibited the oxidative stress and inflammation and reduced apoptosis, particularly L3. Additionally, these compounds diminished the Nrf2 and NF-kB expressions and DNA lesions, principally L4. PAH extract, L5 and L6 exerted antioxidant and anti-inflammatory activities, reduced γH2AX formation and inhibited extrinsic apoptosis and transcription factors activation but to a lesser extent. The loading of quercetin in liposomes increased the cell viability and exerted better endothelial protection compared to free quercetin, especially L3. The liposomes with PAH extract had moderate efficiency, mainly due to the antioxidant and anti-inflammatory effects and the inhibition of extrinsic apoptosis.

Trans-Siberian railway’s flora and its correlation with the characteristics of natural biomes in Baikal Siberia

Проведена инвентаризация чужеродных и аборигенных видов растений вдоль Транссибирской магистрали на участке Тайшет - Улан-Удэ, длина которого составляет 1126 км (12% Транссиба). Выявлена корреляция между характеристиками биомов и основными флористическими показателями. Исследованы 13 железнодорожных станций и участки полотна железной дороги, расположенные в трех естественных биомах. На каждом участке заложены площадки размером 100 м² в трех различных экотопах: на железнодорожном полотне, на откосах и на подошве железнодорожной насыпи в начале полосы отчуждения. Всего составлено 51 геоботаническое описание. Выявлено 266 видов сосудистых растений: 36 древесных, 169 травянистых поликарпиков и 61 травянистый монокарпик. Самое высокое число видов (175) произрастают в наиболее влагообеспеченном Таежном Южносибирском Восточносаянском биоме. 30 видов встречаются во всех трех изученных биомах, более половины из них отмечены нами ранее и на европейском участке Транссибирской магистрали: Acer negundo, Amaranthus retroflexus, Artemisia sieversiana, A. vulgaris, Bromopsis inermis, Convolvolus arvensis, Elytrigia repens, Equisetum arvense, Euphrasia stricta, Kochia scoparia, Medicago falcata, M. lupulina, Odontites vulgaris, Polygonum aviculare, Poa pratensis, Raphanus raphanistrum, Sonchus arvensis, Vicia cracca. Во всех биомах минимальное число видов растет непосредственно на железнодорожном полотне. При этом в обоих Таежных биомах (Восточносаянском и Сохондинском) больше всего видов обнаружено на откосах, а в Бореальном Ангарском подтаежном биоме - в полосе отчуждения. Высокое сходство набора видов (Ks > 50%) наблюдается в Бореальном Ангарском подтаежном биоме и Таежном Южносибирском Восточносаянском биоме для откосов железной дороги и для полосы отчуждения, что отражает наличие «коридора», позволяющего видам, в том числе и инвазионным, расселяться вдоль железной дороги. Значимая положительная корреляция отмечена между численностью «железнодорожных» видов и среднегодовым количеством осадков, и в меньшей степени, среднегодовой температурой биома. Всего треть из выявленных «железнодорожных» видов встречаются как в Байкальской Сибири, так и в европейской части России, и почти половину из них составляют чужеродные таксоны. Число инвазионных видов на Транссибе существенно снижается по направлению с запада (17 видов) на восток (4 вида). Флора Транссибирской магистрали в Байкальской Сибири более обособлена от природной флоры региона, чем в европейской части России, поскольку, а) отсутствует корреляция между численностью «железнодорожных» видов и общей численностью видов сосудистых растений, зарегистрированных в биоме; б) сходство флор трех сибирских биомов отмечено не только по откосам дорог, но и в полосе отчуждения. An inventory of alien and aboriginal plant species was carried out along the Trans-Siberian Railway in the Taishet-Ulan-Ude section, the length of which is 1126 km (12% of the Transsib). A correlation was revealed between the characteristics of biomes and the main floristic indicators. Thirteen railway stations and sections of the railway track located in three natural biomes were investigated. Each site has 100 m² plots in three different ecotopes: on the railway track, on the slopes, and at the foot of the railway embankment at the beginning of the right of way. A total of 51 geobotanical descriptions were compiled. 266 species of vascular plants were identified: 36 arboreal, 169 herbaceous polycarpics, and 61 herbaceous monocarpics. The highest number of species (175) grow in the most moisture-rich Taiga South Siberian East Sayan biome. 30 species are found in all three studied biomes, more than half of them were noted by us earlier and in the European section of the Trans-Siberian Railway: Acer negundo, Amaranthus retroflexus, Artemisia sieversiana, A. vulgaris, Bromopsis inermis, Convolvolus arvensis, Elytrigia repens, Equisetrasum arvense, Euphrasia arvense , Kochia scoparia, Medicago falcata, M. lupulina, Odontites vulgaris, Polygonum aviculare, Poa pratensis, Raphanus raphanistrum, Sonchus arvensis, Vicia cracca. In all biomes, the minimum number of species grows directly on the railroad tracks. At the same time, in both Taiga biomes (East Sayan and Sokhondinsky), most species were found on the slopes, and in the Boreal Angarsk subtaiga biome - in the alienation zone. A high similarity of the set of species (Ks> 50%) is observed in the Boreal Angarsk subtaiga biome and the Taiga South Siberian East Sayan biome for the slopes of the railway, which reflects the presence of a “corridor” that allows species, including invasive ones, to settle along the railway. A significant positive correlation was noted between the abundance of "railroad" species and the average annual rainfall, and to a lesser extent, the average annual temperature of the biome. Only one third of the identified "railroad" species are found both in Baikal Siberia and in the European part of Russia, and almost half of them are alien taxa. The number of invasive species on the Transsib decreases significantly from the west (17 species) to the east (4 species). The flora of the Trans-Siberian Railway in Baikal Siberia is more isolated from the natural flora of the Region than in the European part of Russia, since a) there is no correlation between the number of “railroad” species and the total number of vascular plant species registered in the biome; b) the similarity of the floras of three Siberian biomes was noted not only along the slopes of the roads, but also in the exclusion zone.

In Vitro Study of Two Edible Polygonoideae Plants: Phenolic Profile, Cytotoxicity, and Modulation of Keap1-Nrf2 Gene Expression

Polygonum aviculare and Persicaria amphibia (subfam. Polygonoideae) are used in traditional cuisines and folk medicine in various cultures. Previous studies indicated that phytochemicals obtained from Polygonoideae plants could sensitize chemoresistant cancer cells and enhance the efficacy of some cytostatics. Here, the cytotoxic properties of chemically characterized ethanol extracts obtained from P. aviculare and P. amphibia, individually and in combination with doxorubicin (D), were determined against hepatocarcinoma HepG2 cells. Phenolic composition, cell viability, cell cycle, apoptosis, and the expression of Keap1 and Nrf2 were examined by following methods: LC-MS/MS, LC-DAD-MS, MTT, flow cytometry, and qRT-PCR. Extracts were rich in dietary polyphenolics. Synergistic cytotoxicity was detected for extracts combined with D. The observed synergisms are linked to the interference with apoptosis, cell cycle, and expression of Keap1-Nrf2 genes involved in cytoprotection. The combined approach of extracts and D could emerge as a potential pathway of chemotherapy improvement.

Ruderal vegetation in Serbia - diversity and floristic composition

This study represents the first data gathering and analysis of the floristic composition of ruderal vegetation in Serbia, published over the last 70 years. The dataset included 748 relev?s of ruderal communities and a total of 716 plant species and subspecies. The study showed that the most abundant were widespread taxa, especially taxa of the Eurasian area type, while alien species accounted for a relatively small proportion of the ruderal flora (about 10%). Therophytes and hemicryptophytes were most abundant in the life form spectra. Five vegetation groups were identified, corresponding to the following vegetation classes: Bidentetea, Sisymbrietea, Digitario sanguinalis-Eragrostietea minoris, Artemisietea vulgaris and Polygono-Poetea annuae. The analysis of similarity showed that there are small floristic differences between particular vegetation groups. The determined diagnostic species for the vegetation groups were compared with those of the corresponding anthropogenic vegetation classes, and a high degree of similarity was found for all but one group. The most frequent taxa in all five groups were Polygonum aviculare, Convolvulus arvensis, Plantago major subsp. major and Chenopodium album.

The role of seed water content for the perception of temperature signals that drive dormancy changes in Polygonum aviculare buried seeds

Seedling emergence in the field is strongly related to the dynamics of dormancy release and induction of the seed bank, which is mainly regulated by soil temperature. However, there is limited information on how temperature-driven effects on dormancy changes are modulated by the seed hydration-level. We investigated the effect of seed water content (SWC) on the dormancy release and dormancy induction in Polygonum aviculare L. seeds. We characterised quantitatively the interaction between seed water content (SWC) and temperature through the measurement of changes in the lower limit temperature for seed germination (Tl) during dormancy changes for seeds with different SWC. These relationships were inserted in existing population-based threshold models and were run against field obtained data. The model considering SWC was able to predict P. aviculare field emergence patterns. However, failure to consider SWC led to overestimations in the emergence size and timing. Our results show that in humid temperate habitats, the occurrence of eventual water shortages during late-winter or spring (i.e. short periods of water content below 31% SWC) can affect soil temperature effects on seed dormancy, and might lead reductions in the emergence size rather than to significant temporal displacements in the emergence window. In conclusion, SWC plays an important role for the perception of temperature signals that drive dormancy changes in buried seeds.