Praxelis Clematidea Research Articles

Influence of arbuscular mycorrhizal fungi on root foraging and competitive ability depends on soil phosphorus distribution: evidence from two pairs of invasive and native plants

Besides uptake of nutrients by roots, plants can acquire nutrients through arbuscular mycorrhizal fungi (AMF). AMF play a crucial role in plant growth and competition. However, few studies have investigated the effects of AMF on root foraging and competition between invasive and native species in response to heterogeneous nutrients. Two pairs of invasive and native plants of the Asteraceae family were selected to create a common garden experiment involving three factors (heterogeneous vs. homogeneous phosphorus (P), with vs. without AMF, and monoculture vs. mixture). The results showed that AMF significantly reduced the foraging scale of the invasive species, Bidens pilosa, and decreased the precision of the invasive species, Praxelis clematidea, and the native species, Emilia sonchifolia. In monoculture, AMF significantly decreased the total biomass of the two invasive species under heterogeneous P rather than homogeneous P, which was confirmed by N and P uptake. In mixture, heterogeneity significantly decreased the tolerance competitive ability of B. pilosa but increased that of P. clematidea. In the homogeneous P, AMF significantly decreased the suppression ability of B. pilosa, while in the heterogeneous P, AMF decreased that of P. clematidea. Heterogeneous P with AMF increased the suppression ability of B. pilosa but decreased that of P. clematidea. The interactive effects of AMF and soil P distribution on root foraging and nutrient uptake and competition differ among the four species and show invasive-native pair differences. These findings provide valuable insights into the interactive effects and highlight the context dependency of these interactions.

Occurrence of Praxelis clematidea Witches'-Broom Disease Association with 16SrI Group 'Candidatus Phytoplasma asteris' in Hainan Island of China.

Praxelis clematidea is an invasive herbaceous plant belonging to Asteraceae family. From August to November 2020, the plants showing severe witches'-broom symptoms were found in farms and roadsides from Ding'an of Hainan Province, a tropical island of China. The disease symptoms were suggestive of phytoplasma infection. For pathogen detection, P. clematidea samples consisting of six symptomatic and three asymptomatic plants were collected from the farms and roadsites of Ding'an with 40 % incidence by conducting surveys and statistics. Total nucleic acids were extracted using 0.10 g of fresh leaf tissues of the plant through CTAB DNA extraction method. Conserved gene sequences of 16S rRNA and secA genes from phytoplasma were amplified by direct PCR using primer pairs of R16mF2/R16mR1 and secAfor1/secArev3, respectively. R16mF2/R16mR1 PCR amplicons were obtained for all symptomatic samples but not from the symptomless plants. The amplicons were purified and sequenced by Biotechnology (Shanghai) Co., Ltd. (Guangzhou, China). Sequences of 16S rRNA gene (1323 bp) and secA (732 bp) were obtained and all the gene sequences were identical, designated as PcWB (Praxelis clematidea witches'-broom)-hnda. Representative sequencs were deposited in Genbank with accession numbers of PP098736 (16S rDNA) and PP072216 (secA). Nucleotide BLAST (Basic Local Alignment Search Tool) search based on 16S rRNA gene sequences indicated that PcWB-hnda had 100% sequence identity (1323/1323) with 'Candidatus Phytoplasma asteris'-related strains belonging to 16SrI group like Waltheria indica virescence phytoplasma (MW353909) and Capsicum annuum yellow crinkle phytoplasma (MT760793); had 99.62 % sequence identity (1321/1326) with the phytoplasma strains of 16SrI group such as Oenothera phytoplasma (M30790). RFLP (Restriction Fragment Length Polymorphism) pattern derived from 16Sr RNA gene sequences by iPhyClassifier showed identical (similarity coefficient=1.00) to the reference pattern of 16SrI-B subgroup (GenBank accession number: AP006628). The results obtained demonstrate that the phytoplasma strain PcWB-hnda under study is a member of 16SrI-B subgroup. A BLAST search based on secA gene sequences indicated that PcWB-hnda shares 100% sequence identity (732/732 bp) with Pericampylus glaucus witches'-broom phytoplasma (MT875200), 99% sequence identify (728/732 bp) with onion yellows phytoplasma OY-M(AP006628), and 99% sequence identify (729/732 bp) with rapeseed phyllody phytoplasma isolate RP166 (CP055264), among other phytoplasma strains that belong to 16SrI group. Previous studies demonstrated that P. clematidea can be infected by phytoplasmas affiliate to the 16SrII group (GenBank accession number: KY568717 and EF061924) in Hainan Island of China. To our knowledge, this is the first report of a natural infection of P. clematidea by a group 16SrI phytoplasma in the Island of China. 16SrI group can infect agronomic important species such as areca palm in the island and P. clematidea can be a reservoir of 16SrI phytoplasmas. Therefore, it is necessary to search of potential vectors of the pathogens, which would contribute to epidemiological monitoring and prevention of the related diseases.

Identification of Vernonia patula Merr. and Its Similar Varieties Based on a Combination of HPLC Fingerprinting and Chemical Pattern Recognition.

Vernonia patula Merr. (VP) is a traditional medicine used by the Zhuang and Yao people, known for its therapeutic properties in treating anemopyretic cold and other diseases. Distinguishing VP from similar varieties such as Praxelis clematidea (PC), Ageratum conyzoides L. (AC) and Ageratum houstonianum Mill (AH) was challenging due to their similar traits and plant morphology. The HPLC fingerprints of 40 batches of VP and three similar varieties were established. SPSS 20.0 and SIMCA-P 13.0 were used to statistically analyze the chromatographic peak areas of 37 components. The results showed that the similarity of the HPLC fingerprints for each of the four varieties was >0.9, while the similarity between the control chromatogram of VP and its similar varieties was <0.678. Cluster analysis and partial least squares discriminant analysis provided consistent results, indicating that all four varieties could be individually clustered together. Through further analysis, we found isochlorogenic acid A and isochlorogenic acid C were present only in the original VP, while preconene II was present in the three similar varieties of VP. These three components are expected to be identification points for accurately distinguishing VP from PC, AC and AH.

The potential of invasive species Praxelis clematidea extract as a bioherbicide for Asystasia gangetica

Abstract. Wardini TH, Afifa IN, Esyanti RR, Astutiningsih NT, Pujisiswanto AH. 2023. The potential of invasive species Praxelis clematidea extract as a bioherbicide for Asystasia gangetica. Biodiversitas 24: 4738-4746. The occurrence of weeds in agriculture directly impacts crop productivity, and the reliance on synthetic herbicides to solve the problem has raised concerns about the increasing environmental damage. Using bioherbicides to control weeds is necessary to reduce the negative impact of synthetic herbicides. Bioactive compounds derived from plants can be utilized to develop eco-friendly herbicides. Praxelis clematidea extract was reported to exhibit allelopathic activity against weeds. This study aims to evaluate the potential of P. clematidea extract as a bioherbicide to control seed germination and seedling growth of Asystasia gangetica weed. P. clematidea water extract was screened for its chemical compounds and determined its phytotoxic effects on Asystasia gangetica. The results showed that P. clematidea water extract contained phenolics, alkaloids, and terpenoids. P. clematidea extract suppressed seed germination, the time needed for seed germination, sprout length, number of leaves, biomass, and total chlorophyll contents. LC50values for the seed germination, seedling, root, and shoot growth were calculated at 9%, 25%, 11%,and 37% (v/v), respectively. Thus, P. clematidea could be used as an A. gangetica weed biocontrol agent and might be integrated into weed management programs.

Sesquiterpenes from two Compositae plants as promising inhibitors to nuclear hormone receptor 3 of Tribolium castaneum

Essential oils (EOs) and their volatile secondary metabolites have been proved to be effective on storage pests control, while restricted on the application due to unclear mechanism. Molecular dynamics (MD) simulations and binding free energies analysis provided an effective approach to reveal mechanism on conformational calculation. In this work, the insecticidal and repellent capacities of Praxelis clematidea and Ageratum houstonianum oils and their main components identified by gas chromatography–mass spectrometry (GC–MS) were scientifically measured. Interestingly, P. clematidea oil exhibited strong fumigant toxicity against Tribolium castaneum (LC50 = 7.07 mg/L air). Moreover, two EOs exhibited over 80% repellent rate against T. castaneum at the highest concentration of 78.63 nL/cm2. Furthermore, hundreds of enzymes related to the regulation of biological processes of T. castaneum were screened to explore the underlying molecular mechanism and develop promising insecticides. Besides, top hits were subjected to MD simulations and binding free energies analysis to elucidate complex inter-molecular stability and affinity over simulated time. The results demonstrated that isolongifolene, δ-cadinene, β-caryophyllene and caryophyllene oxide were prioritized as they were establishing conserved and stable interactions with residues of nuclear hormone receptor 3 (TcHR3) of T. castaneum, which suggested that the four sesquiterpenes have potential to be promising insecticides on storage pests control.

Anti-inflammatory Actions of Praxelis Clematidea

Praxelis clematidea is a plant species that belongs to the Asteraceae family. It is native to South America and has been traditionally used in folk medicine for its medicinal properties. Researchers have investigated the chemical constituents of Praxelis clematidea and identified several anti-inflammatory phenolics and phenylpropanoids. Here is some information about these compounds: The anti-inflammatory properties of Praxelis clematidea phenolics and phenylpropanoids make them of interest for potential therapeutic applications. Studies have identified various phenolics and phenylpropanoids in Praxelis clematidea, including flavonoids, caffeic acid derivatives, coumarins, and lignans. Some of the specific compounds reported include clematidin, clematomandshurin, clematoside-I, clematoside-II, and praxelin. Liang and his colleagues have demonstrated the anti-inflammatory activity of these compounds. They have been shown to inhibit the production of pro-inflammatory molecules, such as nitric oxide (NO), prostaglandin E2 (PGE2), and pro-inflammatory cytokines like interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α). They can inhibit the activation of transcription factors like nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1), which are key regulators of inflammatory responses. The authors concluded that given their anti-inflammatory properties, the phenolics and phenylpropanoids from Praxelis clematidea have the potential for use in the development of natural anti-inflammatory agents or as leads for drug discovery targeting inflammation-related conditions. Fitoterapia. 2023 Jun;167:105476. doi: 10.1016/j.fitote.2023.105476.

Pengaruh Ekstrak Daun Senduduk Bulu (Clidemia hirta L.) terhadap Perkecambahan dan Pertumbuhan Gulma (Praxelis clematidea)

Weeds are plants whose existence is not expected by farmers because they interfere with cultivated plants. But there are weeds that can produce phenolic compounds such as Clidemia hirta L which can be used as bioherbicides. This study aims to determine the effect of Clidemia hirta L. leaf extract on the germination and growth of Praxelis clematidea weeds. The research was carried out from June 2021 to September 2021 at the Weed Science Laboratory and Integrated Field Laboratory, Faculty of Agriculture, University of Lampung. This study used a completely randomized design (CRD) method with 6 treatments with concentrations of Clidemia hirta L leaf extract, namely 0; 1.5; 3.0; 4.5; 6.0; and 7.5%. Each treatment was repeated 6 times to obtain 72 experimental units. The observed variables are germination, crown height, root length, dry weight, and weed poisoning level. The data obtained were analyzed by analysis of variance and continued with the Least Significant Difference Test (LSD) at the 5% level. The results showed that the germination of Praxelis clematidea weed was significantly inhibited by the treatment of Clidemia hirta L leaf extract with a concentration of 1.5; 3.0; 4.5; 6.0; and 7.5%. While concentrations of 3.0%, 4.5%, 6.0%, and 7.5% Clidemia hirta L. leaf extract inhibited the growth of Praxelis clematidea weeds in the greenhouse. Key words: Clidemia hirta L., extract, Praxelis clematidea, germination, growth

Anti-inflammatory phenolics and phenylpropanoids from Praxelis clematidea

Praxelis clematidea (Asteraceae) is a noxious invasive exotic plant in southern China, and it has caused great damage to ecological conditions and serious financial losses. In this study, four new phenolics (1, 2, 7, 8), and two new phenylpropanoids (3, 4), along with seventeen known compounds were separated and purified from the whole plant of P. clematidea. Their chemical structures were determined by extensive spectroscopic analysis methods. Additionally, the potential inhibitory activities on nitric oxide (NO) production and NF-κB nuclear translocation in LPS-triggered RAW 264.7 macrophages of the isolated compounds were evaluated. Notably, compounds 2, 7, and 8 showed significant inhibitory activities on NO production, and also inhibited the expression of iNOS and COX-2. Furthermore, compounds 2, 7, and 8 effectively suppressed the NF-κB nuclear translocation. These findings suggest that P. clematidea has the potential to be developed and promoted as a treatment for inflammation-related diseases.

First report of 16SrII-V phytoplasma associated with cowpea (Vigna unguiculata) phyllody in China

Cowpea plants exhibiting virescence, phyllody and little leaf symptoms were observed in the fields of Zhanjiang City, Guangdong province of China in October 2020. Total DNA was extracted from symptomatic cowpea leaves. Using phytoplasma universal primer pairs (R16mF2/R16mR1, P1/P7) and a secA primer pair (secAfor1/secArev3), expected PCR fragments of approximately 1400, 1800 and 800 bp were amplified from all symptomatic cowpea leaves. MUSCLE analysis revealed that the representative 16S rRNA gene sequence of cowpea phyllody phytoplasma (CPP) shared 98.67% nucleotide identity with the reference strain WBDL of ‘Ca. Phytoplasma aurantifolia’ (GenBank accession number U15442); and 100% nucleotide identity with 16SrII-V phytoplasmas associated with ‘Praxelis clematidea’ phyllody (GenBank accession number KY568717); ‘Desmodium triflorum’ little leaf (GenBank accession number MT452308); and ‘Ixeris chinensis’, ‘Emilia sonchifolia’, and ‘Desmodium ovalifolium’ witches’ broom (GenBank accession number MT416114, MT420682 and MK956144, respectively). Phylogenetic analyses based on the 16S rRNA and secA gene sequences revealed that the CPP strain clustered with the 16SrII-V subgroup and 16SrII group, respectively. Virtual restriction fragment length polymorphism analysis of the 16S rRNA sequence revealed that CPP was associated with the 16SrII-V subgroup. To our knowledge, this is the first report of the16SrII-V subgroup of phytoplasmas associated with cowpea phyllody disease.

Aqueous Cr (VI) removal performance of an invasive plant-derived biochar modified by Mg/Al-layered double hydroxides

In this study, MgAl layered double hydroxides (Mg-Al/LDH)-decorated invasive plant (Praxelis clematidea)-derived biochar (MgAl/LDH-PBC) were prepared by the co-precipitation method. The characterization results revealed that the modified biochar surface offered more active adsorption sites, facilitating the Cr (VI) adsorption. MgAl/LDH-PBC showed an excellent adsorption capacity of 177.88 mg/g in a monolayer, with a rapid uptake equilibrium within 180 min. In addition, even after five cycles, the desorption rates remained at about 85%, and the Cr (VI) adsorption was quite stable despite the presence of a number of other ions. Moreover, MgAl/LDH-PBC bonded efficiently with Cr (VI) via electrostatic interaction, oxidation-reduction reaction, ion-exchange reaction, complexation, and co-precipitation. Based on these findings, MgAl/LDH-PBC may be used as an adsorbent for the removal of Cr (VI) from sewage and the management of invasive plant species.

Effects of grazing on vegetation diversity and soil multifunctionality in coconut plantations.

Grazing is the main way of utilizing understory vegetation in the tropics. However, the effects of grazing on vegetation diversity and soil functions in coconut plantations remain unclear. Therefore, this study was conducted in a young coconut plantation that was grazed by geese in Wenchang, China. We identified four grazing intensities according to the aboveground biomass, namely, no grazing (CK), light grazing (LG), moderate grazing (MG), and heavy grazing (HG). In April 2022, we used the quadrat method to investigate the composition and traits of vegetation, collected and analyzed 0-40-cm soil samples in each grazing intensity. The results showed that grazing changed the composition of understory species. The predominant species changed from Bidens pilosa to Praxelis clematidea + Paspalum thunbergii and then to P. clematidea with increasing grazing intensity. The richness, Shannon-Wiener index, evenness, modified functional attribute diversity (MFAD), functional divergence (Fdiv), and functional evenness (Feve) of CK were 4.5, 1.0, 0.29, 0.20, 0.84, and 0.80, respectively. Taxonomic diversity did not respond to LG, but responded significantly to MG and HG. Compared with CK, MG and HG increased richness by 96% and 200%, respectively, and Shannon-Wiener index increased by 40% and 98%, respectively. HG increased evenness by 95%. For functional diversity, MG and HG increased MFAD by 164% and 560%, respectively, but Fdiv and Feve did not respond to grazing intensity. The carbon (C) functioning, nitrogen (N) functioning, phosphorus (P) functioning, and multifunctionality in the 0-10-cm topsoil of CK were -0.03, 0.37, -0.06, 0.20, and 0.14, respectively. Grazing increased C functioning, P functioning, and multifunctionality in the 0-10-cm topsoil but decreased N functioning. Multiple linear regression showed that the taxonomic diversity and functional diversity could be used to estimate soil functions, but these vary among soil layers. In general, MG and HG can increase vegetation diversity and soil function. It may be possible to promote even distribution of geese by adding water sources or zoning grazing. Furthermore, quantitative grazing experiments are needed to determine the efficient use pattern of the understory in coconut plantations in tropics.

The Complete Chloroplast Genome Sequence of Eupatorium fortunei: Genome Organization and Comparison with Related Species.

Eupatorium fortunei Turcz, a perennial herb of the Asteraceae family, is one of the horticultural and medicinal plants used for curing various diseases and is widely distributed in China and other Asian countries. It possesses antibacterial, antimetastatic, antiangiogenic, and antioxidant properties along with anticancer potential. However, the intrageneric classification and phylogenetic relationships within Eupatorium have long been controversial due to the lack of high-resolution molecular markers, and the complete chloroplast (cp) genome sequencing has not been reported with new evolutionary insights. In the present study, E. fortunei was used as an experimental material, and its genome was sequenced using high-throughput sequencing technology. We assembled the complete cp genome, and a systematic analysis was conducted for E. fortunei, acquiring the correspondence of its NCBI accession number (OK545755). The results showed that the cp genome of E. fortunei is a typical tetrad structure with a total length of 152,401 bp, and the genome encodes 133 genes. Analysis of the complete cp genomes of 20 Eupatorieae shows that the number of simple sequence repeats (SSRs) ranged from 19 to 36 while the number of long sequence repeats was 50 in all cases. Eleven highly divergent regions were identified and are potentially useful for the DNA barcoding of Eupatorieae. Phylogenetic analysis among 22 species based on protein-coding genes strongly supported that E. fortunei is more closely related to Praxelis clematidea and belongs to the same branch. The genome assembly and analysis of the cp genome of E. fortunei will facilitate the identification, taxonomy, and utilization of E. fortunei as well as provide more accurate evidence for the taxonomic identification and localization of Asteraceae plants.

Effect of Landscape Composition and Invasive Plants on Pollination Networks of Smallholder Orchards in Northeastern Thailand

Destruction of natural habitat, land-use changes and biological invasion are some of the major threats to biodiversity. Both habitat alteration and biological invasions can have impacts on pollinator communities and pollination network structures. This study aims to examine the effect of an invasive plant, praxelis (Praxelis clematidea; Asteraceae), and land-use types on pollinator communities and the structure of pollination networks. We conducted the study in smallholder orchards which are either invaded or non-invaded by P. clematidea. We estimated the pollinator richness, visitation rates, and pollinator diversity and evaluated the network structures from 18 smallholder orchards in Northeastern Thailand. The effect of landscape structure in the vicinity of the orchards was investigated, with the proportion of agricultural, forest, and urban landscape within a 3 km radius analyzed. The invasive species and land-use disturbance influence the pollinator communities and pollination network structure at species level was affected by the presence of P. clematidea. Bees were the most important pollinator group for pollinator communities and pollination networks of both invaded or non-invaded plots, as bees are a generalist species, they provide the coherence of both the network and its own module. The urban landscape had a strong negative influence on pollinator richness, while the proportions of agriculture and forest landscape positively affected the pollinator community.

Isolation and Identification of Antibacterial and Antifungal Compounds from Praxelis clematidea R. M. King &amp; H. Robinson as an Effective Potential Treatment against Rice Pathogens

Bacterial leaf blight and blast diseases caused by the bacterium Xanthomonas oryzae pv. oryzae and the fungus Pyricularia oryzae, respectively, are among the most important infectious diseases affecting rice. We evaluated the antimicrobial effects of compounds derived from Praxelis clematidea on Xanthomonas oryzae and Pyricularia oryzae. The dried aerial parts of Praxelis clematidea were subjected to ethanol extraction, separated by solvent partitioning using hexane, chloroform, ethyl acetate, and water. In vitro assays demonstrated that the main antibacterial and antifungal activities were distributed in the ethyl acetate and chloroform fractions, respectively. These fractions were further separated using silica gel chromatography and reversed-phase chromatography. Finally, we isolated five compounds, 1–5, that inhibited the growth of Xanthomonas oryzae in vitro and four compounds, 6–9, that exhibited in vitro antifungal activity against Pyricularia oryzae. We evaluated their antimicrobial activities and identified their chemical structures by NMR and mass spectrometry analyses. This is the first study to isolate compound 2 (4,4′,4″-nitrilotriphenol) as an alternative microbial from natural resources and evaluate its physiological activity. Moreover, this is the first report to demonstrate antibacterial activity in comparison with flavonoids. Praxelis clematidea extracts plausibly exert both antibacterial and antifungal effects, which should be further validated in field trials.

Adaptability and 'Candidatus Liberibacter asiaticus' titres of Diaphorina citri adults on three weed species in China.

Diaphorina citri is a vector of 'Candidatus Liberibacter asiaticus' (CLas), which is associated with citrus huanglongbing (HLB). In this study, the adaptability and CLas titres of D. citri adults on three weed species, namely, Ageratum conyzoides, Solanum nigrum and Praxelis clematidea, which are widely distributed in citrus orchards in China, were determined. D. citri selected S. nigrum preferentially over the other weed species. The longest survival times of D. citri adults on A. conyzoides, S. nigrum and P. clematidea were 48, 41 and 11 days, respectively. On S. nigrum, the survivorship of females was significantly higher than that of males. The CLas titres of D. citri adults feeding on the three weeds for 1 week increased significantly during autumn but did not change significantly during spring. Conversely, the titres of adults on citrus increased significantly during spring but did not change significantly during autumn. D. citri exhibited different adaptabilities to the three weed species, but the CLas titres of D. citri adults did not decrease on any of the weeds. These results suggested that the three weed species could help dispersing of D. citri and transmission of CLas while ideal host conditions were scarce or absent. © 2021 Society of Chemical Industry.

Efficacy of Post-Emergence Herbicides against Important Weeds of Sugarcane in North-East Thailand

Weeds represent a significant problem in Thailand’s sugarcane production. The various cycles of sugarcane cultivation result in degrees of weed severity in which each species requires a different weed control method, the most popular of which is the post-emergence herbicide method. However, sugarcane farmers often use incorrect rates, and operators’ safety is missing or applications are not selective, causing toxicity and interrupted growth of sugarcane. The effects of post-emergence herbicide types, time, and application rates are presented herein, through an experiment in Northeast Thailand, conducted in a randomized complete block design (RCBD) with four replications. The herbicides paraquat and ametryn were evaluated, with paraquat being more effective, yet resulting in higher toxicity and lower yield components. We may conclude through our experiments that ametryn and paraquat can be applied only once for sugarcane at the tillering stage and at rates of 540 and 2400 g ai ha−1, respectively. These rates were lower than the recommended rates, which represented the minimum doses necessary to control Thailand’s dominant weed species like Brachiaria distachya (L.) Stapf., Dactyloctenium aegyptium (L.) P.B., Praxelis clematidea R.M King &amp; H. Rob and Pennisetum polystachion (L.) Schult. Consequently, the adequate control of weeds is a rather case-specific situation and therefore each weed species should be taken into account.

Autonomous apomixis in Praxelis clematidea (Asteraceae: Eupatorieae), an invasive alien plant.

Understanding the reproductive mechanisms of invasive alien species can lay the foundation for effective control measures. Praxelis clematidea is a triploid neotropical Asteraceae species that is invasive in China and other countries. However, few studies have focused on its reproductive biology. In this study, flow cytometric seed screening (FCSS) was used to identify and confirm the reproductive mode of the species. The development of ovules, anthers, and mega- and microgametophytes was observed using a clearing method and differential interference contrast microscopy. Pollen viability was measured using the Benzidine test and Alexander’s stain. Pollen morphology was observed via fluorescence microscopy after sectioning the disk florets and staining with water-soluble aniline blue or 4′6-diamidino-2-phenylindole nuclei dyes. Controlled pollination experiments were conducted on four populations in China to examine the breeding system and to confirm autonomous apomixis. The reproductive mode was found to be autonomous apomixis without pseudogamy, according to FCSS. Megaspore mother cells developed directly into eight-nucleate megagametophytes without meiosis, conforming to Antennaria-type diplospory. The unreduced egg cells developed into embryos through parthenogenesis, while the endosperm was formed by the fusion of two unreduced polar nuclei. Pollen viability was very low (0.82 ± 0.57 % and 0.36 ± 0.44 %) as measured by the Benzidine test and Alexander’s stain, respectively. The majority of the pollen grains were empty and had neither cytoplasm nor nuclei. The seed set was >90 % for all treatments of open pollination, bagging and emasculated capitula. Mature cypselae developed in capitula that were emasculated before flowering, which confirmed that the breeding system of P. clematidea was autonomous apomixis. The present study is the first report of autonomous apomixis in P. clematidea in China. Antennaria-type autonomous apomixis in P. clematidea greatly increases the probability of successful colonisation and dispersal of P. clematidea into new areas, which likely contributes to its high invasion potential. Effective control measures should be implemented to prevent autonomous (pollen-independent) seed production.

Characterization and utilization of biochars derived from five invasive plant species Bidens pilosa L., Praxelis clematidea, Ipomoea cairica, Mikania micrantha and Lantana camara L. for Cd2+ and Cu2+ removal

Exotic invasive plants endanger the integrity of agricultural and natural systems throughout the world. Thus, the development of cost-effective and economic application of invasive plants is warranted. Here, we characterized fifteen biochars derived from five invasive plants at different temperatures (300, 500, and 700 °C) by determining their yield, ash content, pH, CEC, surface area, elementary composition, functional groups, and mineral composition. We conducted batch adsorption experiments to investigate the adsorption capacity and efficiency for Cd2+ and Cu2+ in wastewater. Our results suggest that all invasive plants are appropriate for biochar production, temperature and plant species had interacting effects on biochar properties, and the biochars pyrolyzed at 500 and 700 °C exhibited high metal adsorption capacity in neutral (pH = 7) solutions. The adsorption kinetics can be explained adequately by a pseudo-second-order model. BBC500 (Bidens pilosa L. derived biochar at 500 °C) and MBC500 (Mikania micrantha) exhibited higher metal equilibrium adsorption capacities (38.10 and 38.02 mg g−1 for Cd2+, 20.01 and 20.10 mg g−1 for Cu2+) and buffer abilities to pH than other biochars pyrolyzed at 500 °C. The Langmuir model was a better fit for IBC500 (Ipomoea cairica), MBC500, and LBC500 (Lantana camara L.) compared to the Freundlich model, whereas the opposite was true for BBC500 and PBC500 (Praxelis clematidea). These results suggest that the adsorption of metals by IBC500, MBC500, and LBC500 was mainly monolayer adsorption, while that by BBC500 and PBC500 was mainly chemical adsorption. Our results are important for the utilization and control of invasive plants as well as the decontamination of aqueous pollution.

Structure-based virtual screening of bioherbicide candidates for weeds in sugarcane plantation using in silico approaches

Weeds in sugarcane have negatively affected the sugar yield rate. Several approaches have been carried out to overcome the weeds, including the usage of diuron as synthetic herbicide. However, the long-term usage of diuron is known to have a negative effect leads to the production of 3,4- Dichloroaniline responsible for soil leach and bioaccumulation. Therefore, this study aimed to find a potential natural herbicide. By mimicking the diuron's mode of action which inhibits the process of photosynthesis through blocking the Photosystem II protein D1 (psbA) of the weeds, fourteen compounds as potential candidate bioherbicides were virtually docked by PyRx v0.9.5 software to the specific site. Three important species of the weeds were chosen including Eleusine indica, Praxelis clematidea, and Momordica charantia. The binding affinity score was further calculated and ranked to screen the top six compounds as bioherbicide candidates. Interaction of each complex and the biological activity prediction were then performed by Discovery Studio software and PASS server, respectively. Aurachin P, Aurachin A, and Cyanobacterin were placed in the top ranked compounds with high binding affinity score around -6 to -9 kcal mol-1 toward the psbA. The amino acid interaction involved in the complex shows 50-90% similar to the control, psbA and diuron complex. Besides, the biological activity prediction of Aurachin P, Aurachin A, and Cyanobacterin exhibits the terms related to the inhibition of photosynthesis process via enzymatic pathway. Thus, the active compounds might have inhibition action in the photosynthesis process and control the weeds in sugarcane.

Antimicrobial and anti-adherent potential of the ethanolic extract of Praxelis clematidea (Griseb.) R.M.King &amp; Robinson on pathogens found in the oral cavity

With the evolution of bacterial resistance over conventional antimicrobials and the development of new antimicrobials, the search for new compounds of natural origin has intensified, since plants with therapeutic potential constitute a source of new biologically active compounds, encouraging the development of new therapeutic options. The objective of this study was to evaluate the antibacterial and anti-adherent activity of the ethanolic extract of Praxelis clematidea (Griseb.) R.M. King &amp; Robinson (Asteraceae) on strains of Staphylococcus aureus, Streptococcus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa and Enterococcus faecalis. Tests were carried out to determine the MIC and MBC by means of broth microdilution in 96-well plates, and to determine the MICA, a technique with inclined tubes in the presence of 5% sucrose was used. It was observed that the ethanolic extract of P. clematidea has strong bactericidal activity on K. pneumoniae, and moderate bactericidal activity on S. pneumoniae and E. faecalis. Being able to inhibit adherence to K. pneumoniae strains. Thus, the ethanolic extract of P. clematidea proves to be effective as an antimicrobial in the control and prevention of infections by S. pneumoniae, K. pneumoniae and E. faecalis. It also has an effective anti-adherent effect on K. pneumoniae strains.