Commelina Communis Research Articles

Selection and validation of reference genes for qRT-PCR normalization in dayflower (Commelina communis) based on the transcriptome profiling

BackgroundDayflower (Commelina communis), a widely invasive weed, thrives well under a variety of abiotic stresses, including drought and herbicides, and harms the growth of crops such as maize and soybean. Gene expression in dayflower is an important but understudied area due to the lack of reliable reference genes.ResultsFifteen candidate reference genes, which are common reference genes and homologous to those used in other plants, were selected through RNA-seq datasets of dayflower. The expression stability of these screened reference genes was evaluated under three abiotic stresses (drought, herbicide and copper) and in five organs (roots, stems, leaves, flowers and seeds) using five commonly used software programs (geNorm, NormFinder, BestKeeper, ΔCt and RefFinder). The results showed that API5 and SAND had the highest stability in stems, while SAND, EF1A and API5 had the highest stability in roots. Moreover, SAND, ALDH113 and API5 were most stably expressed under copper stress, and EF1A, SAND and API5 were most stable under drought stress. SAND was consistently the most stably expressed gene in both the organs and all samples. Notably, The SAND gene ranked among the top three in terms of stability in all abiotic treatments and in various organs. This result indicates that the SAND gene is suitable for qRT-PCR experimentation in diverse tissues and under multiple (drought, herbicide and copper) abiotic stress conditions in dayflower.ConclusionThis study identified the most stably expressed reference genes under three abiotic stresses and in five organs of dayflower, and SAND showed high expression stability under various experimental conditions, making it a reliable reference gene for gene expression analysis experiments under different conditions in dayflower. This study will enhance the precision of the qRT-PCR quantification of candidate genes related to the adaptation significance of dayflower.

Structural characterization and Bacteroides proliferation promotion activity of a novel homogeneous arabinoglucuronoxylan from Commelina communis L.

Commelina communis L., a functional food and herbal plant in Asia, has been used against obesity, diabetes, and infections for centuries. A growing body of studies has demonstrated that indigestible polysaccharides are significant in obesity management. However, the structures and bioactivities of homogeneous polysaccharides from C. communis remain unclear. This study presented the structural characterization, simulated digestion, and human gut Bacteroides proliferation promotion activity of a novel homogeneous polysaccharide (CCB-3) from C. communis. The results showed that CCB-3 was an arabinoglucuronoxylan, primarily composed of arabinose, galactose, xylose, glucuronic acid (GlcA), and 4-O-methyl GlcA with a molecular weight (Mw) of 58.8 kDa. Following a 6-hour exposure to simulated gastrointestinal fluid, the Mw of CCB-3 remained unchanged, revealing that CCB-3 was an indigestible polysaccharide. Notably, CCB-3 could promote the proliferation of B. thetaiotaomicron, B. ovatus, and B. cellulosilyticus and produce short-chain fatty acids (SCFAs) and 1,2-propanediol. These findings might shed light on the discovery of polysaccharide-based leading compounds from C. communis against obesity.

Allopolyploidy enhances survival advantages for urban environments in the native plant genus Commelina.

Urbanization-induced environmental changes affect the geographical distribution of natural plant species. This study focused on how polyploidization, a dynamic genome change, influences the survival and distribution of Commelina communis L. (Cc) and its subspecies, C. communis f. ciliata (Masam.) Murata (Ccfc) which have different chromosome numbers (e.g. Cc: 2n = 88, Ccfc: 2n = 46). The aim is to investigate polyploidization effects on natural plant distribution in urban environments. The geographical distribution across urban-rural gradients was investigated at a total of 218 sites in Japan. Stomata size and density were measured and compared between Cc and Ccfc. Flow cytometry determined genome size and polyploidy. Chromosome karyotyping was performed using genomic in situ hybridization (GISH) method. Urban areas were exclusively dominated by Cc, while Cc and Ccfc coexisted in rural areas. Cc had larger and fewer stomata and more than twice the genome size than Ccfc. GISH results indicated that Cc possesses Ccfc and another unknown genome, suggesting allopolyploidy. Our results show that the ploidy difference affects the geographical distribution, the stomata traits, and genome size between two distinct taxa in the genus Commelina, C. communis as a neo-tetraploid and C. communis f. ciliata, the diploid. Cc is an allopolyploid, therefore, not only polyploidy but also an additional genome with new sets of genes and alleles contributes to Cc having enhance survival potentials in urban environments compared to Ccfc. This is the first investigation to clarify the distribution difference related to urban environments, the difference in stomata traits and genome size, and to conduct chromosome composition in Commelina species.

Does a coexisting congener of a mixed mating species affect the genetic structure and selfing rate via reproductive interference?

Reproductive interference is defined as an interspecific interaction that reduces fitness via mating processes. Although its ecological and evolutionary consequences have attracted much attention, how reproductive interference affects the population genetic structures of interacting species is still unclear. In flowering plants, recent studies found that self-pollination can mitigate the negative effects of reproductive interference. Selfing-biased seed production is expected to increase population-level inbreeding and the selfing rate, and limits gene flow via pollinator outcrossing among populations. We examined the population genetics of the mixed-mating annual herb Commelina communis f. ciliata, focusing on reproductive interference by the sympatric competing congener C. communis using microsatellite markers. First, we found that almost all C. c. f. ciliata populations had relatively high inbreeding coefficients. Then, comparing sympatric and allopatric populations, we found evidence that reproductive interference from a competing congener increased the inbreeding coefficient and selfing rate. Allopatric populations exhibit varied selfing rates while almost all sympatric populations exhibit extremely high selfing rates, suggesting that population selfing rates were also influenced by unexamined factors, such as pollinator limitation. Besides, our findings revealed that reproductive interference from a competing congener did not limit gene flow among populations. We present the first report on how reproductive interference affects the genetic aspects of populations. Our results suggested that the high selfing rate of C. c. f. ciliata promotes its sympatric distribution with C. communis, even in the presence of reproductive interference, although it is not clear whether reproductive interference directly causes the high selfing rate.

Effect of aluminum on growth and herbicide resistance in Commelina communis and Tradescantia fluminensis, two invasive weed species in tea gardens

Effect of aluminum on growth and herbicide resistance in Commelina communis and Tradescantia fluminensis, two invasive weed species in tea gardens

Efficiencies of Heavy Metal Hyper-accumulation Plants as Potential Land Remediators for Heavy Metal Polluted Soils

The purpose of this study was to determine which hyper accumulator plant is more efficient for phytoremediation of heavy metals in a heavy metal polluted soil. The plants used were Sunflower (Helianthus annuus), Asiatic dayflower (Commelina communis), Guinea grass (Panicum maximum), Bahama grass (Cynodon dactylon), and Vertiver grass (Chrysopogon zizanioides). Heavy metals such as Pb, Zn, Cu, Cd, Ag and Hg were impregnated in the soil samples and analyzed using atomic absorption spectrophotometer (AAS). The plants were planted in the heavy metal polluted soil and harvested after 75 days to determine the percentage concentration of the heavy metals in the root and shoot of the plants. The result showed that heavy metals were hyper-accumulated in the roots and shoots of the plants at the end of the investigation. The heavy metals with a percentage concentration above 50 % can be used as a phytoremediator of that particular metal in a polluted soil. It was discovered that the best hyperaccumulator plants for Pb is the Sunflower, for Zn and Cd is the Bahama grass, for Cu and Ag is the Vertiver grass whilst, for Hg is the Guinea grass.

Habitat diversification associated with urban development has a little effect on genetic structure in the annual native plant Commelina communis in an East Asian megacity.

Urban development greatly alters the natural and semi-natural habitats of native plants. Urbanisation results in a range of diverse habitats including remnant agricultural lands, urban parks, and roadside habitats. This habitat diversity often promotes trait divergence within urban areas. However, the mechanisms by which diverse urban habitats influence the population genetic structure of individual plant species remain poorly understood. We investigated the effects of urbanisation on genetic diversity and structure within 24 Commelina communis populations across diverse habitat types (rural agricultural land, urban agricultural land, urban park land, and urban roadsides) within the Kyoto-Osaka-Kobe megacity in Japan. We conducted multiplexed inter-simple sequence repeat genotyping to compare genetic diversity among populations in different habitats. We also examined the correlation between Nei's genetic distance and geographic and environmental distances and performed principal coordinate analysis (PCoA) to evaluate genetic differentiation among urban habitats. There were no significant differences in genetic diversity indices between urban and rural populations and among urban habitat types. Although we detected no isolation-by-distance structure in population pairs of the same habitat type and in those of different habitats, the difference in surrounding landscape facilitated genetic differentiation not only between urban and rural habitats but also between different urban habitats. PCoA revealed no clear genetic differentiation among rural and urban habitat populations. Our findings indicate that the establishment of diverse habitat types through urbanisation has no and little impact on genetic diversity and structure, respectively, in C. communis, likely due to its high selfing rate and ability to adapt to urban conditions.

Multi-metabolomics and intestine microbiome analysis: YZC extract ameliorates septic-ALI by modulating intestine microbiota to reduce TMAO/NLRP3 signaling

BackgroundSepsis causes inflammation in response to infection, often leading to acute lung injury (ALI). Yazhicao (Commelina communis L., YZC) is widely distributed in the global tropics and has good anti-respiratory inflammatory activity; however, the protection of YZC against septic-ALI has not been established. PurposeThe role of YZC in septic-ALI will be investigated in this study. Methods and resultsIn this study, YZC was shown to inhibit excessive inflammation and alleviate septic-ALI. Network pharmacology predicts that Quercetin, Acacetin and Diosmetin have the potential to serve as the pharmacological substance basis of YZC in alleviating septic-ALI. The metabolomics results indicated that YZC could improve the metabolic disorders caused by septic-ALI, which were mostly concerned with energy metabolism and amino acid metabolism, with Trimethylamine (TMA)/Trimethylamine N-oxide (TMAO) being potential small molecule metabolic markers for the clinical diagnosis and treatment of septic-ALI. YZC inhibits the initiation and progression of septic-ALI by controlling the TMA/TMAO metabolites. Our results also suggest that YZC protects the intestinal barrier from damage. Furthermore, our research indicated that YZC reduces TMAO synthesis by inhibiting TMA production through remodeling the intestine microbiota. We investigated the mechanism of YZC-mediated protection against septic-ALI and showed that YZC reduced the expression of proteins associated with NLRP3 inflammatory vesicles in the lung by inhibiting the expression of NF-κB. ConclusionThese results show that YZC inhibits the NF-κB/NLRP3 signaling pathway by regulating metabolic and intestinal flora disorders in septic-ALI mice to reduce TMAO synthesis. This study presents a theoretical groundwork for the advancement of novel medications and clinical use of YZC to enhance septic-ALI and furnishes a theoretical rationale for regulating intestinal microbiota as a therapeutic instrument to treat sepsis and septic-ALI.

Broad bean wilt virus 2 in commelina communis L. in China

In the present study transcriptone sequencing and RT-PCR detection of leaf sample of Commelina communis L. were investigated. A diseased leaf sample was selected for transcriptome sequencing and two contigs with lengths of 5845 and 3450 nucleotides (nt) were obtained. They were confirmed by RT-PCR with seven pairs of primers, and RNA1 and RNA2 (GenBank MZ571836 and MZ571837) were determined to be 5880 nt and 3478 nt, respectively. Homology analysis and evolutionary relationship analysis showed the highest homology with BBWV2 (MN786954 and MN786955), for 97.5 and 88.4% at the nt and amino acid (aa) levels, respectively. This is the first report of BBWV2 infection in C. communis in the world. Specific primers R2-2F/R were used to assess the association of BBWV2 with C. communis disease, and positive fragments were obtained only in the diseased plants, indicating the association of BBWV2 with the disease. Bangladesh J. Bot. 52(2): 569-574, 2023 (June) Special

Broad bean wilt virus 2 in commelina communis L. in China

In the present study transcriptone sequencing and RT-PCR detection of leaf sample of Commelina communis L. were investigated. A diseased leaf sample was selected for transcriptome sequencing and two contigs with lengths of 5845 and 3450 nucleotides (nt) were obtained. They were confirmed by RT-PCR with seven pairs of primers, and RNA1 and RNA2 (GenBank MZ571836 and MZ571837) were determined to be 5880 nt and 3478 nt, respectively. Homology analysis and evolutionary relationship analysis showed the highest homology with BBWV2 (MN786954 and MN786955), for 97.5 and 88.4% at the nt and amino acid (aa) levels, respectively. This is the first report of BBWV2 infection in C. communis in the world. Specific primers R2-2F/R were used to assess the association of BBWV2 with C. communis disease, and positive fragments were obtained only in the diseased plants, indicating the association of BBWV2 with the disease. Bangladesh J. Bot. 52(2): 569-574, 2023 (June) Special

Belowground facilitation of plant mixtures on rhizosphere soil of Commelina communis grown on extremely Cu- and Cd-contaminated mine: From soil quality to bacterial community

Plant–plant interactions exert positive effects under stress conditions, but their impact on heavy metal-contaminated rhizosphere soil quality and bacterial community remains unclear. In this work, the rhizospheric soil of Cu-accumulator Commelina communis and neighboring plants grown in a heavily contaminated copper mine was analyzed to elucidate such belowground facilitation. Physicochemical properties and microbial characteristics of rhizospheric soil of control C. communis (far from neighboring plants), facilitated C. communis (near neighboring plants), and neighboring plants were compared. The average values of total organic carbon, NH4+-N, NO2−-N, NO3−-N, available phosphorus, urease, and phosphatase in the C. communis rhizosphere increased by 0.82-, 0.64-, 0.44-, 0.06-, 0.10-, 0.36-, and 0.30-fold in the presence of surrounding plants, respectively. The relative abundance of oligotrophic bacteria (Chloroflexi) decreased, whereas copiotrophic bacteria (Proteobacteria) increased in plant species mixtures. Venn graph and partial least squares discriminant analysis indicated that the composition of the bacterial community in the facilitated C. communis rhizosphere showed higher similarity to neighboring plants than to control C. communis. Among 49 predicted functional groups analyzed by FAPROTAX analysis, chemoheterotrophy (36.04 %) involved in carbon cycles had the highest relative abundance and increased in the facilitated C. communis rhizosphere due to the positive response of 193 OTUs (mainly belonging to Proteobacteria and Actinobacteriota) under plant–plant interactions. The increased relative abundance of Methylocella and Bradyrhizobium resulted in improved nitrogen fixation in the C. communis rhizosphere, whereas nitrate reduction with its main performer Rubrobacter was inhibited. The ecological function of rhizobiomes of the facilitated C. communis and neighbors also showed higher similarity compared with that of the control C. communis. These results show the role of neighboring plants in modulating soil quality and rhizobiomes of plant remediators under stress and more indoor garden experiments need to be conducted to verify such belowground facilitation.

Efficacy of Sulfentrazone 39.6% and Pendimethalin as a Pre Emergence Application against Weed Spectrum of Soybean (Glycine max L. Merrill)

A field experiment was conducted during Kharif season of 2017 at the Research Farm, College of Agriculture, Jabalpur, Madhya Pradesh. The seven treatments comprising of four doses of sulfentrazone (180, 360, 540 and 720 g/ha), application of pendimethalin (750 g/ha) as pre emergence, hand weeding twice at 20 and 40 days after sowing (DAS) including weedy check, were laid out in randomized block design with 3 replications. Results revealed that, Echinochloa colona (28.24%) was the dominant weed species closely followed by Commelina communis (24.42%). However, other monocot weed like Cyperus rotundus (15.56%) and dicots like Phyllanthus niruri (19.34%) and Euphorbia hirta (12.44%) were also found associated with soybean in less numbers. Application of T4- sulfentrazone at 720 g/ha as pre emergence arrested the weed growth remarkably and proved superior to its lower dose (180 g/ha) and application of pendimethalin 750 g/ha. The poor crop-weed competition due to effective control of weeds under this treatment resulted in higher weed control efficiency. Pre-emergence application of T4- sulfentrazone at 720 g/ha recorded maximum grain yield and was at par with other individual herbicides. Similarly, higher net returns and benefit: cost ratio were recorded in T4- sulfentrazone at 720 g/ha fb T3- sulfentrazone at 540 g/ha. It may be inferred from the present investigation that these herbicidal treatments could be used effectively as an alternative for controlling weeds and obtaining optimum seed yield of soybean.

Assessing the Effect of Weed Management Practices on Weed Flora, Growth and Yield of Fodder Maize (Zea mays L.)

A field experiment was conducted at Research Farm, AICRP on Forage Crops, Department of Agronomy, JNKVV, Jabalpur (Madhya Pradesh) during of the year 2019. The main objective of the experiment was to find out the effect of different weed control treatments on complex weed flora in fodder maize. Ten treatments were tested in randomized block design with three replications. Treatments consisted of pre-emergence application of atrazine 1000 g/ha, pendimethalin 750 g/ha, atrazine 750 g/ha + pendimethalin 750 g/ha and post emergence application of 2, 4-D 500 g/ha, tembotrione 120 g/ha, topramezone 35 g/ha, tembotrione 120 g/ha + atrazine 250 g/ha, topramezone 35 g/ha + atrazine 250 g/ha, hand weeding twice at 20 and 40 DAS and weedy check. Weed intensity and dry matter accumulation by weeds were recorded species wise and then the effectiveness of weed management and the weed control efficiency were calculated. In maize field, the predominated weeds were Echinochloa colona, Commelina communis, and Digitaria sanguinalis among monocots, Phyllanthus niruri and Eclipta alba among dicots along with a respectable sum of numerous minor weeds. Experimental results indicated that hand wedding has recorded highest weed control efficiency (88.64%) followed by PoE application of topramezone 35 g/ha + atrazine 250 g/ha (74.38%) and tembotrione 120 g/ha + atrazine 250 g/ha (68.31%). All weed control treatments significantly affected the plant height, LAI, stem girth and leaf: stem ratio of crop. Among different herbicidal treatments, topramezone 35 g/ha + atrazine 250 g/ha was found significantly superior and gives highest green fodder yield (47.26 t/ha), dry fodder yield (13.64 t/ha), crude protein yield (1.51 t/ha), net monetary returns (Rs. 44824/ha) and B: C ratio (2.72). Thus, herbicide application of topramezone 35 g/ha + atrazine 250 g/ha was found more reliable to control complex weed flora of fodder maize with higher green fodder yield and net returns.

Weed Dynamics of Fodder Maize as Influenced by Different Herbicides

The advancements in fodder maize cultivation practices over the past few years, has paved a change in the makeup of weed associations. This made it necessary to incorporate new, effective herbicides in the struggle against maize's primary weeds. Therefore, a field experiment was conducted at Research Farm, AICRP on Forage Crops, Department of Agronomy, JNKVV, Jabalpur (Madhya Pradesh) during Kharif season 2019 to devise an appropriate combination of herbicides required for the control of the complex weed diversity in fodder maize. The field experiment was laid out in randomized block design (RBD) with ten treatments (eight herbicidal combinations along with hand weeding twice at 20 and 40 DAS and a weedy check) and replicated thrice. Observations were recorded on the weed parameters and fodder yield of maize. Among monocots, the experimental field was infested with Echinochloa colona, Commelina communis and Digitaria sanguinalis. Phyllanthus niruri and Eclipta alba were dominated among dicots. Among all herbicidal treatment, topramezone 35 g/ha plus atrazine 250 g/ha was found to be significantly superior in reducing total weed density (9.49/m2, 11.50/m2) and total weed dry weight (6.43 g/m2, 7.91 g/m2) at 30 and 45 DAS, respectively and recorded the lowest weed index (1.82%). Also, the maximum green fodder yield (472.68 q/ha) was recorded in topramazone 35 g/ha + atrazine 250 g/ha compared to other treatments. Overall, this study indicated that the combination of topramazone 35 g/ha + atrazine 250 g/ha could be an alternative approach to hand weeding and alone herbicides in fodder maize.

Antibacterial Components and Modes of the Methanol-Phase Extract from Commelina communis Linn.

Infectious diseases caused by pathogenic bacteria severely threaten human health. Traditional Chinese herbs are potential sources of new or alternative medicine. In this study, we analyzed for the first time antibacterial substances in the methanol-phase extract from a traditional Chinese herb-Commelina communis Linn-which showed an inhibition rate of 58.33% against 24 species of common pathogenic bacteria. The extract was further purified using preparative high-performance liquid chromatography (Prep-HPLC), which generated four single fragments (Fragments 1 to 4). The results revealed that Fragment 1 significantly increased bacterial cell surface hydrophobicity and membrane permeability and decreased membrane fluidity, showing disruptive effects on cell integrity of Gram-positive and Gram-negative bacteria, such as Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus, and Salmonella enterica subsp., compared to the control groups (p < 0.05). In sum, 65 compounds with known functions in Fragment 1 were identified using liquid chromatography and mass spectrometry (LC-MS), of which quercetin-3-o-glucuronide was predominant (19.35%). Comparative transcriptomic analysis revealed multiple altered metabolic pathways mediated by Fragment 1, such as inhibited ABC transporters, ribosome, citrate cycle and oxidative phosphorylation, and upregulated nitrogen metabolism and purine metabolism, thereby resulting in the repressed bacterial growth and even death (p < 0.05). Overall, the results of this study demonstrate that Fragment 1 from C. communis Linn is a promising candidate against common pathogenic bacteria.

Resonance Raman and Visible Micro-Spectroscopy for the In-Vivo and In-Vitro Characterization of Anthocyanin-Based Pigments in Blue and Violet Flowers: A Comparison with HPLC-ESI- MS Analysis of the Extracts

Microanalysis techniques based on resonance Raman and reflection visible spectroscopy have been applied to the characterization of pigments responsible for the blue or violet coloration in flowers; in particular of Lobelia erinus, Campanula portenschlagiana, Cineraria, Viola tricolor, Anemone coronaria, Agapanthus, Platycodon, Salvia farinacea, Plumbago capensis, Ceratostigma plumbaginoides, Commelina communis and Salvia patens. The spectroscopic methods were applied both in vivo on the flower petals and in vitro on extracts obtained through a procedure based on SPE (solid-phase extraction) optimized for minimal quantities of vegetable raw material. Different patterns obtained for the Raman spectra have been correlated, also on the basis of density functional theory (DFT) calculations, with different schemes of substitution of the benzopyrilium nucleus of the anthocyanins and with various possible forms of copigmentation responsible for the stabilization of the blue color. The results obtained were verified by comparison with the analysis of the extracts by HPLC-ESI-MS (liquid chromatography-electrospray ionization-mass spectrometry).

Quality evaluation of Commelina communis from different origins based on multicomponent content determination combined with chemometrics

This research established a high-performance liquid chromatography(HPLC) method for simultaneous determination of isoorientin, orientin, vitexin, and isovitexin in Commelina communis to conduct content difference analysis and quality evaluation of 62 batches of C. communis from different origins. The HPLC content determination was performed on a Dikma Platisil ODS chromatographic column(4.6 mm×250 mm, 5 μm), with acetonitrile-0.1% formic acid(14∶86) as the mobile phase. The detection wavelength was set at 348 nm, the flow rate was 1.0 mL·min~(-1), and the column temperature was 35 ℃. The differences in origins and quality of 62 batches of C. communis were studied by chemometrics. The results showed that the determination of four components mani-fested a good linear relationship in the range of mass concentration(r&gt;0.999 9), and the average recovery rate was 96.17%-103.0%. The relative standard deviations(RSDs) of precision, stability, and repeatability were all less than 2.0%. The content of four components from high to low was isoorientin&gt;isovitexin&gt;orientin&gt;vitexin. Forty-seven batches of C. communis with clear origins were classified into six categories by chemometrics. C. communis from different origins had different qualities. Generally, C. communis from Western China, Central China, and South of China had superior qualities. The HPLC method established in this study is specific, simple, and efficient, which provides references for the comprehensive evaluation of the quality of C. communis. The chemometrics shows that the qualities of C. communis from different origins are largely different. Isoorientin can be used as an index to determine the content of C. communis, and its content limit should be set no less than 0.023%.

Asiatic dayflower (Commelina communis) control in Douglas fir

AbstractAsiatic dayflower (Commelina communis L.) is becoming increasingly invasive in Christmas tree plantations in the U.S. Northeast. Response of C. communis to preemergence or postemergence herbicides was evaluated in separate field and greenhouse experiments. The preemergence herbicides consisted of two application rates of flumioxazin (215 and 429 g ai ha−1), hexazinone plus sulfometuron-methyl (316 and 527 g ai ha−1), indaziflam (41 and 82 g ai ha−1), and S-metolachlor (2,136 and 4,272 g ai ha−1). The postemergence herbicides were: bentazon at 1,121 g ai ha−1, clopyralid at 280 g ae ha−1, mesotrione at 526 g ai ha−1, topramezone at 294 g ai ha−1, and triclopyr at 842 g ae ha−1. At 16 wk after treatment, higher rates of flumioxazin (429 g ha−1), hexazinone plus sulfometuron-methyl (527 g ha−1), indaziflam (82 g ha−1), and S-metolachlor (4,272 ha−1) provided 80% to 92% control and reduced C. communis plant density by 84% to 93% compared with the nontreated control. The lower rates of flumioxazin (215 g ha−1), hexazinone plus sulfometuron-methyl (316 g ha−1), and S-metolachlor (2,136 ha−1) gave 65% to 72% control and reduced C. communis plant density by 27% to 75% compared with the nontreated control. The postemergence application of mesotrione at 526 g ha−1, topramezone at 294 g ha−1, and triclopyr at 842 g ha−1 resulted in 76% to 90% control and reduction in dry biomass of 10- to 12-leaf C. communis at 28 d after treatment. Bentazon at 1,121 g ha−1 and clopyralid at 280 g ha−1 applied postemergence were ineffective with &lt;10% control and reduction in C. communis dry biomass. This study showed that C. communis can be managed effectively with currently registered preemergence and postemergence herbicides in Christmas trees.

Phase sensitivity of some broad-leaved weed species to the herbicide Flex

The effect of herbicide Flex, AS (active ingredient fomesafen 250 g/l) on annual weed species common in soybean crops was studied. The studies were conducted under greenhouse conditions in 2019-2021. The sensitivity of ragweedAmbrosia artemisiifoliaL., Asian copper leafAcalypha australisL., common lamb's quartersChenopodium albumL., common dayflowerCommelina communisL., China juteAbutilon theophrastiMedik, trailing hollyhockHibiscus trionumL., St.-Paul’swortSigesbeckia pubescensMakino, green amaranthAmaranthus retroflexusL., elsholtziaElsholtzia pseudocristataLevl. et Vaniot, and Siberian cockleburXanthium sibiricumPatrin ex Widd was determined. Weed treatment with Flex at rates of 0.75, 1.0, 1.25 and 1.5 l/ha was carried out three times a season at different stages of plant growth and development. The level of sensitivity of weed species to herbicide was judged by the decrease in height and weight of the aboveground organs of the experimental plants compared to the control. It was found that Flex herbicide completely destroys plants of all tested species in the early stages of growth and development (1-4 true leaves). When treating weeds that have formed 3-10 leaves, ragweed, green amaranth, Asian copper leaf, trailing hollyhock and Siberian cocklebur remain highly sensitive to the drug action (reduction of the aboveground weight up to 94-100%). Application of Flex on overgrown plants leads to a significant decrease in its activity against all studied weed species. When used in the third term, the herbicide is effective only on the green amaranth, suppressing the mass of the plants by 76-86%.

PsbA gene over-expression and enhanced metabolism conferring resistance to atrazine in Commelina communis

Commelina communis L. is a troublesome weed in agronomic fields and increasingly threatens the yield security of corn in north-eastern China. Previously, we found that a C. communis population (JL-1) has evolved resistance to atrazine. Although the potential genetic and enzymic differences contributing to atrazine resistance in this population have been investigated, the specific molecular mechanisms underlying C. communis resistance are still poorly understood. Here, the expression level of the target gene PsbA and the non-target-site resistance (NTSR) mechanism for this population were studied. The results showed that the decline in chlorophyll content in JL-1 leaves was less than in the susceptible JS-10 population following atrazine treatment. JL-1 exhibited an enhanced expression of the PsbA gene compared with JS-10 of 7.28- and 14.28-fold higher at 0 and 24 h after treatment with atrazine, respectively. The cytochrome P450 monooxygenase (P450) inhibitor piperonyl butoxide (PBO) increased the phytotoxicity of atrazine in both populations of C. communis. Seven candidate genes associated with NTSR of Jl-1 were identified through RNA-seq and validated by quantitative real-time PCR, including 5 upregulated genes involved in herbicide metabolism. In addition, the activities of glutathione S-transferases and P450s in JL-1 were increased compared with JS-10. Collectively, PsbA gene overexpression and enhanced metabolism are likely to be responsible for JL-1 resistance to atrazine.