Rumex Dentatus Research Articles

Weed population, weed biomass and grain yield of wheat as influenced by herbicides application

A field experiment was conducted during Rabi seasons of 2015–16 and 2016–17 at Banka (Bihar) to evaluate the weed population, weed biomass and grain yield as influenced by herbicide application in wheat (Triticum aestivum L.). Seven weed species, viz. Phalaris minor, Cynodon dactylon, Chenopodium album, Oxalis purpurea, Anagallis arvensis, Medicago denticulata and Rumex dentatus infested the wheat field. Post-emergence application of sulfosulfuron 75% WG (25 g/ha) + metsulfuron-methyl 20% WP (2 g/ha) at 30 days after sowing (DAS) was very effective against broad-leaf weeds and annual grasses, and recorded significantly lower density and biomass of these weeds at 60 DAS as compared to isoproturon 75% WP 1.0 kg/ha, sulfosulfuron 75% WG 50 g/ha, metsulfuron-methyl 20% WP 4 g/ha and weedy check. Ear length, effective tillers/m2, grains/spike, grain and straw yields were also significantly higher in sulfosulfuron (25 g/ha) + metsulfuron-methyl (2 g/ha) as compared to other herbicide treatments.

Phenolic profiling and therapeutic potential of local flora of Azad Kashmir; In vitro enzyme inhibition and antioxidant

AbstractThe current study supports the phytochemical screening, evaluation of antioxidant and enzyme inhibition potential and correlations between antioxidant activities and phenolics of Rumex dentatus (Family: Polygonaceae), Mentha spicata (Family: Lamiaceae), Withania somnifera (Family: Solanaceae), Nerium indicum (Family: Apocynaceae) and Artemisia scoparia (Family: Asteraceae). The herbal materials were extracted in ethanol (90%) and partitioned between several solvents based on polarities. Total phenols were determined with FC method and ranged 21.33 ± 1.53 - 355.67 ± 6.03 mg GAE/ mg of the extract. Antioxidant activities (DPPH, total iron reducing capacity, phosphomolybdate assay & FRAP) and enzyme inhibition potential (Protease, AChE & BChE) were performed by the standard protocols. The results showed that all extracts exhibited significant DPPH activity ranging from 12.67 ± 2.08 - 92.67 ± 1.53%. The extracts that were active in DPPH activity also potrayed marvelous FRAP, total iron reducing and phosphomolybdate values. Correlation studies of antioxidant activities and the content of phenolic compounds in plant materials exhibited positive correlation between them. The outcome of enzyme inhibition activity exhibited that about 80% of the fractions under surveillance plants intimated more than 50% inhibition. Isolation of bioactive compounds from these plants is in progress.

Allelopathic Activity and Chemical Composition of Rhynchosia minima (L.) DC. Essential Oil from Egypt.

Aromatic plants attract the attention of many researchers worldwide due to their worthy applications in agriculture, human prosperity, and the environment. Essential oil (EO) could be exploited as effective alternatives to synthetic compounds as it has several biological activities including allelopathy. The EO from the aerial parts of Rhynchosia minima was extracted by hydrodistillation and investigated by gas chromatography/mass spectrometry (GC/MS). Different concentrations (50, 100, 150 and 200μLL-1 ) of the EO were prepared for investigation of their allelopathic potential on two weeds; Dactyloctenium aegyptium and Rumex dentatus. Twenty-eight compounds, mainly sesquiterpenes (69.13%) were determined. The major compounds are α-eudesmol, 2-allyl-5-tert-butylhydroquinone, caryophyllene oxide, trans-caryophyllene, and τ-cadinol. The EO from the R.minima showed a significant inhibition of D.aegyptium and R.dentatus germination, while the seedling growth was stimulated. Therefore, it is not recommended to treat these noxious weeds with the EO of R.minima before the germination. In contrast, the apparent stimulatory effect on the seedling growth offers further studies to use the EO of R.minima to enhance the fitness of different economic crops. However, characterization of green bio-herbicides such as EO (allelochemicals) from wild plants raises a new opportunity for the incorporation of new technology of bio-control against the noxious weeds.

Heavy metal phytoextraction potential of native weeds and grasses from endocrine-disrupting chemicals rich complex distillery sludge and their histological observations during in-situ phytoremediation

Sugarcane-molasses based distillery waste is a threat to environment for its safe disposal due to complexation of endocrine-disrupting chemicals (EDCs) containing mixture of organic pollutants. This study revealed that distillery sludge contains not only mixture of complex organic pollutants but also retains high quantity of Fe (5264.49), Zn (43.47), Cu (847.46), Mn (238.47), Ni (15.60), and Pb (31.22 mg kg−1) which enhances the toxicity of sludge to the environment. The major identified organic compounds were benzene, 1-ethyl-2-methyl, benzene, 1-ethyl-4-methyl benzoic acid, 3,4,5-tris(TMS oxy), TMS ester; hexanedioic acid, dioctyl ester; stigmasterol TMS ether; 5α-cholestane,4-methylene; campesterol TMS; β-sitosterol and lanosterol. These compounds are listed under the EDCs also as per U.S. Environmental Protection Agency. However, the phytoextraction potential of growing native weeds and grasses i.e. Argemone mexicana, Saccharum munja, Cynodon dactylon, Pennisetum purpureum, Chenopodium album, Rumex dentatus, Tinospora cordifolia, Calotropis procera and Basella alba revealed the high accumulation of Fe, Zn, Cu, Mn, Ni, and Pb in their root and leaves compared to shoot. This indicated high accumulation and translocation capabilities of these plants. Further, the bioaccumulation coefficient factor (BCF) and translocation factor (TF) was found >1 for majority of plants for various metals. Thus, this given strong evidence for hyperaccumulation tendency of these native weeds and grasses from complex polluted sites. Furthermore, the ultrastructural observations of root tissues also revealed the deposition of heavy metals at various cellular components without any apparent toxic effects. This indicated the variable adaptive characteristics of these plants growing at a hazardous waste polluted site. Thus, the study given a strong evidence for application of these weeds and grasses as tools for in-situ phytoremediation and eco-restoration of polluted sites.

Analysis of organic acids of tricarboxylic acid cycle in plants using GC-MS, and system modeling

BackgroundLeaves of 15 plant species were collected from the catchment areas of the river Beas, Punjab, India, and analyzed for organic acids of tricarboxylic acid cycle, viz., citric acid (CA), succinic acid (SA), fumaric acid (FmA), and malic acid (MA).MethodsGas chromatography-mass spectrometry (GC-MS) was used to determine the content of organic acids in the leaves of plant species. Two microliters of plant sample was injected into the GC-MS, and the concentration of organic acids was quantified using standard curve.ResultsAverage concentrations of these acids in the leaves of plants studied were 4.79, 0.98, 0.54, and 8.36 mg/g dw, respectively. The maximum contents of these acids were found in the leaves of Chenopodium album (CA = 6.42 mg/g dw), Argemone mexicana (SA = 1.27 and FmA = 0.73 mg/g dw), and Rumex dentatus (MA = 18.0 mg/g dw). Factor analysis revealed mainly two underlying factors for organic acids: Factor-1 having maximum loadings on SA and FmA and Factor-2 had maximum loadings on CA and MA. Multiple linear regression analysis of MA on other acids showed that CA and SA have positive regressions, whereas FmA has a negative regression on MA. In artificial neural network analysis, correlation between the target and output values of MA was found to be highly significant. System transfer coefficients were calculated from simulation graphs fitted to the mean values of different organic acids by using difference equations.ConclusionsFrom the present study, it was found that citric acid has a maximum direct effect on the malic acid as compared to succinic and fumaric acids as revealed by path analysis. System modeling revealed that the rate of utilization of malic acid is about 9%. The present study describes a new system simulation technique in which a pathway comprising of linear transformation of biochemical constituents may be characterized in terms of its rate transfer coefficients.

Rumex dentatus Inhibits Cell Proliferation, Arrests Cell Cycle, and Induces Apoptosis in MDA-MB-231 Cells through Suppression of the NF-κB Pathway.

Background: Rumex dentatus, commonly known as tooth docked, is widely used in traditional system of medicines. Although it is well reported for its biological activities and medicinal value, only few studies have been carried out to assess its anticancer potential.Purpose: This study seeks to evaluate the anticancer activity of leaf extracts of R. dentatus against breast cancer MDA-MB-231 cell line, a triple negative human breast cancer cell line with invasive properties and to identify the molecular targets underlying its mechanism of action.Methods: Cytotoxicity of plant extracts was determined against breast cancer cells, using the MTT assay. Flow cytometry was performed to analyze the changes in cell cycle and apoptotic effect, if any. Cells were also studied for their wound healing and invasive potential as well as for Western blotting of apoptotic genes and nuclear factor-kappaB (NF-κB) pathway.Results: The results revealed that R. dentatus methanol (RM) and chloroform (RC) extracts of R. dentatus had the highest inhibition of cell proliferation in a concentration- and time-dependent manner. This inhibitory effect was found to be linked to arrest of cell cycle at the G0/G1 phase, along with induction of apoptosis and accumulation in the sub-G1 phase. Moreover, it was shown that both RM and RC inhibited the proliferation of the malignant cells and induced apoptosis by repressing the activation of NF-κB and its subsequent transcripts, Bcl-xl, Bcl-2, Cyclin D1, survivin, and XIAP. Apoptosis was also confirmed in the cells as suggested by caspase-3 detection. RM and RC also abrogated IκBa phosphorylation in the malignant cells as well as reduced the invasive and migratory capabilities of these cells.Conclusion: Our findings suggest that the methanol and chloroform extracts of R. dentatus may have anti-cancer compounds that are potentially useful in the treatment of human breast cancer.

Differential expression of vacuolar and defective cell wall invertase genes in roots and seeds of metalliferous and non-metalliferous populations of Rumex dentatus under copper stress

Acid invertase activities in roots and young seeds of a metalliferous population (MP) of Rumex dentatus were previously observed to be significantly higher than those of a non-metalliferous population (NMP) under Cu stress. To date, no acid invertase gene has been cloned from R. dentatus. Here, we isolated four full-length cDNAs from the two populations of R. dentatus, presumably encoding cell wall (RdnCIN1 and RdmCIN1 from the NMP and MP, respectively) and vacuolar invertases (RdnVIN1 and RdmVIN1 from the NMP and MP, respectively). Unexpectedly, RdnCIN1 and RdmCIN1 most likely encode special defective invertases with highly attenuated sucrose-hydrolyzing capacity. The transcript levels of RdmCIN1 were significantly higher than those of RdnCIN1 in roots and young seeds under Cu stress, whereas under control conditions, the former was initially lower than the latter. Unexpected high correlations were observed between the transcript levels of RdnCIN1 and RdmCIN1 and the activity of cell wall invertase, even though RdnCIN1 and RdmCIN1 do not encode catalytically active invertases. Similarly, the transcript levels of RdmVIN1 in roots and young seeds were increased under Cu stress, whereas those of RdnVIN1 were decreased. The high correlations between the transcript levels of RdnVIN1 and RdmVIN1 and the activity of vacuolar invertase indicate that RdnVIN1 and RdmVIN1 might control distinct vacuolar invertase activities in the two populations. Moreover, a possible indirect role for acid invertases in Cu tolerance, mediated by generating a range of sugars used as nutrients and signaling molecules, is discussed.

An Investigation of the Major Wheat Weeds in Different Zones of Dera Ismail Khan

On account of huge yield losses, weed infestation is a serious threat in wheat crops throughout the country. A comprehensive survey to find out the major weeds in wheat in Dera Ismail Khan was carried out during the crop season of 2012-13. Wheat fields at seed farms of Rakhmanghan, RakhZandani, Rata Kulachi and adjacent farmer’s fields to each seed farm were investigated. Data was collected at the peak growth stage of weeds and the quadratic method was used to record relative density (RD), relative frequency (RF), relative crowding coefficient (RCC) and importance value index (IVI). The results revealed that the major and most problematic weed of wheat at all the locations was Avena fatua (wild oat) on account of having maximum IVI at Rakh Manghan (78.51 & 77.44), Rata Kulachi (77.82 & 77.54) and Rakh Zandani (77.51 & 77.53) seed Farms and Farmer’s fields respectively. Rumex dentatus (dock) and Convolvulus arvensis (Lehli) were the second and third abundantly occurring weeds at almost all the seed farms and farmer fields on account of having the second and third highest IVI values at all the locations. Therefore Avena fatua (wildoat), Rumex dentatus (dock) and Convolvulus arvensis (lehli) seed were collected to find out the yield losses through further experimentation.

Studies on Fungal Pathogens of Terrestrial Weeds of Kurukshetra

During extensive surveys conducted to search for naturally occurring fungal pathogens on various terrestrial weeds of Kurukshetra and its adjoining areas, dominance of Deuteromycetous fungi followed by obligate fungal pathogens were noticed. A total of 12 fungal pathogens were identified on 10 weeds belonging to 9 different families of Angiosperms on the basis of their morphological characteristics. Typical disease symptoms were produced by all non obligate pathogens on their respective hosts in vitro. Inoculated pathogens were isolated and were found similar to original isolates in cultural characteristics thus confirming the pathogenicity to their respective hosts and competing Koch's postulates. Leaf spots, powdery mildews, downy mildews, rust, and smut were the main diseases caused by the fungal pathogens on various terrestrial weeds of Kurukshetra. Symptoms of diseases caused by these pathogens and cultural characteristics of 12 fungal pathogens were recorded. Alternaria cassiae on Cassia occidentalis, Cercospora sp.-I on Ageratum conyzoides, Cercospora sp.-II on Alhagi camelorum, Cercospora sp.-III on Alternanthera pungens, Cercospora sp.-IV on Argemone mexicana, Cercosporsa sp.-XI on Peristrophe bicalyculata, Peronospora arborescens on Argemone mexicana, Puccinia sp. on Rumex dentatus, Ustilago cynodontis on Cynodan dactylon, Oidium sp.-I on Ageratum conyzoides, Oidium sp-IV on Sida rhombifolia and Peronospora sp. on Chenopodium album are new reports of occurrence of these pathogens from this region.

Control of mixed weed flora in wheat with sequential application of pre-and post-emergence herbicides

The field efficacy of pre-and post-emergence herbicides for control of mixed weed flora in wheat was evaluated in a field study conducted at Punjab Agricultural University, Ludhiana during Rabi seasons of 2014–15 and 2015–16. The season long growth of weeds reduced wheat yield upto 38.5%. Pendimethalin and metribuzin recorded 65–73 and 73–78% control of Phalaris minor, respectively and their tank-mix application enhanced P. minor control to 78–85%. Pendimethalin and metribuzin recorded 26–33 and 5863% control of Medicago denticulata, respectively and their tank-mix application enhanced control to 77–92% of this weed. Pendimethalin and metribuzin provided control of Rumex dentatus to the extent of 98–100% and 68–92%, respectively, while provided 98–100 and 63–72%, respectively control of C. album. Sequential application of pendimethalin as pre-emergence followed by sulfosulfuron as post-emergence recorded the highest weed control efficiency (96%) and wheat grain yield (4.8 t/ha), and it was at par to pre-emergence pendimethalin + metribuzin, post-emergence pinoxaden + metsulfuron, mesosulfuron + iodosulfuron, sulfosulfuron + metsulfuron and two hand weeding.

Response of Wheat to Varying Densities of Rumex Dentatus under Irrigated Condition of Dera Ismail Khan, Pakistan

Response of Wheat to Varying Densities of Rumex Dentatus under Irrigated Condition of Dera Ismail Khan, Pakistan

CORRELATION AND REGRESSION ANALYSIS OF MORPHOLOGICAL TRAITS IN RUMEX DENTATUS

Rumex dentatus is an important crop plant weed and also serves as medicinal plant through out the world. Present study was conducted to access the genetic variability and association among morphological traits of Rumex dentatus under four different locations. The results indicated that the fresh plant weight was significant related with dry weight and moisture contents/percentage in Rumex dentatus plants. The location 3 serves as the best place for growth and development of Rumex dentatus. Hence, it was suggested that the growth and development of Rumex dentatus should be controlled through proper techniques to reduce yield losses in crop plants.

Phenology and seed germination behaviours of some wetland macrophytes at Biratnagar, Nepal

Phenology, seed morphology, seed viability and germination behabiour of some wetland plants in control at moist filter paper in petridishes was carried out in wetland plants-Aeschynemone asper L. (Fabaceae); Eragrostis unioloides (Retz.) Nees exsteudel (Poaceae); Hygrophila auriculata (K. Schum) Heine (Acanthaceae); Pesicaria barbatum (L.) Hara (Polygonaceae); and Rumex dentatus L. (Polygonaceae) were studied at Biratnagar. Number of seeds per gram ranged between161-12722. Viable seeds of A. asper (98%) and P. barbatum (55%) had no germination but E. unioloides had cent percent germination; H. auriculata, and Rumex dentatus showed 96% germination. A.asper and E. unioloides germinated in early rainy; spent vegetative phase up to August- September; and completed flowering, fruiting and seed maturation before winter.

Phytoextraction potential of heavy metals by native wetland plants growing on chlorolignin containing sludge of pulp and paper industry

The results of physico-chemical analysis of pulp and paper mill effluent sedimented sludge revealed the presence of heavy metals (mgl−1) Fe (67.53), Zn (13.90), Cu (2.15), Cr (2.30), Cd (0.255), Mn (11.0), Ni (3.30), and Pb (1.05) along with persistent chlorolignin. The major persistent organic pollutants detected by GC–MS were ethane, 1,1-diethoxy; tetradecanoic acid; furane 2,5-dimethyl; n-hexadecanoic acid; nonacosane, trimethylenebis-1,3-dioxolane; 1,3-dioxolane, 2-(phynylmethyl). Twelve representative native plants were noted based on their population number growing on pulp and paper sludge and evaluated for their phytoextraction potential of heavy metals. The result revealed that Triticum aestivum was found as root accumulator for all metals except Cu. Similarly, the Brassica campestris accumulated all metals maximum in root except Ni, Fe and Pb. While, Eclipta alba accumulated majority of metals in their shoot and leaves, But Solanum nigrum, Rumex dentatus accumulated metals in root and shoot both. Rananculus scleratus accumulated all the tested metals in their aerial parts except Cd and Pb. Cammelina benghalensis accumulated metals in root except Cd, Pd. Similarly the Phragmites cummunis and Ricinus cummunis accumulated majority of metals in their shoot and leaves. It was also noted that several evaluated plant showed bioconcentration factor (BCF) greater than one for accumulated metals i.e. Pb in T. aestivum (1.285), C. benghalensis (5.142), Cannabis sativa (3.466), P. cummunis (7.180), R. cummunis (66.80) was also noted. Furthermore, greater than one translocation factor (TF) for all these plants showed strong evidence for phytoextraction and in situ remediation potential of these plants. The overall order of phytoextraction potential of native wetland plants were C. sativa>P. cummunis>C. benghalensis>T. aestivum>B. campestris>E. alba.

A novel survey of the ethno medicinal knowledge of dental problems in Manoor Valley (Northern Himalaya), Pakistan

Ethnopharmacological relevanceIn the study area, the traditional knowledge and cultural practices of utilizing medicinal plants in the human healthcare is primarily restricted to the old age members of the community, while younger generation is mostly unaware of the natural wealth usage. Aim of the studyWe provide the first ever ethno medicinal insights into the management of dental disorders in Pakistan. The prime objective of the study was to explore novel knowledge of these local and remote community members and share it with rest of the world in documented form. Materials and methodsField surveys were arranged for collection and documentation of medicinal plants of Manoor valley during 2015. Total 71 local inhabitants were interviewed randomly through questionnaire. The data obtained were quantitatively analyzed using the use value (UVi), relative frequency citations (RFCs), fidelity level index (FL%) and consensus index (CI%). For novel uses all plants were thoroughly checked with previously published articles on the same disorder and analyzed through Jaccard index (JI) and Sorensen's similarity index (QS). The collected specimens after confirmation were submitted to the Herbarium, Department of Botany, Hazara University, Mansehra, Pakistan (HUP). ResultsIn present study 25 plants belonging to 17 families are reported, these plants were used commonly as ethno medicine. There were herbs (64%), shrubs (20%) and trees (16%) whereas, Lamiaceae with 4 species was the leading family. Majority of medicinal plant species were used in treatment of toothache (38%), wound healing (19%), gum infections (16%) whereas and lowest percentage of species were used for mouth ulcer as well as teeth powder (3%). Leaves were the most widely part used plant part in the treatment of different diseases (36%). Dominated medicinal plants with high used values were Juglans regia (UVi=0.94), Rumex dentatus (0.89) and Indigofera heterantha (0.88). Based on the RFC values, the most valuable and cited medicinal plant species used by the traditional drivers are Juglans regia having (RFCs=0.69) and Rumex dentatus (0.58). CI results show that most respondents percentage was for Juglans regia having CI%=69%, followed by Rumex dentatus (57.7%). Medicinal plants with high fidelity level and reported for one dental disorder were Berberis lycium, Geranium wallichianum, Lathyrus aphaca, Platanus orientalis, Sedum spp. and Urtica dioica for toothache. Further, new medicinal uses of Abies pindrow, Ajuga integrifolia, Berberis lycium, Urtica dioica, Indigofera heterantha were recorded for the first time from Pakistan and Astragalus grahamianus, Corydalis cornuta, Prunella vulgaris, Ranunculus muricatus, Rumex hastatus, Stellaria media, Tagetes minuta, Taraxacum officinale and Lathyrus aphaca, across the world for the current reported medicinal uses. All mentioned plant species are reported for the first time ever for dental disorders from Manoor Valley. Nonetheless, this is a novel study as no single ethno medicinal study on dental disorder up-till now has been reported from Pakistan. ConclusionThe present study is the first ever documentation of ethno medicinal practices aiming at the dental disorders in Pakistan, which resulted in 64% of medicinal uses new claims. So, the reported species of remote valley should be further evaluated for proper experimentation and pharmacological activities to authenticate their current traditional usage. Field observation revealed vegetation of the area was generally threatened due to its unwise use by the local communities. Trends like deforestation, over grazing, habitat fragmentation and introduction of the exotic taxa were the visible threats. So conservation of such an important natural God gifted treasure is mandatory.

Efficiency of Rumex dentatus L. Leaves Extract for Enhancing Phytoremediation of Plantago major L. in Soil Contaminated by Carbosulfan

ABSTRACTCarbosulfan and carbofuran induce water pollution and health issues. Such issues may be solved by phytoremediation. Here we tested the potential of adding Rumex dentatus L. leaves extract to Plantago major L. for enhancing phytoremediation of carbosulfan-contaminated soil. The phytoremediation efficiency of P. major L. amended with R. dentatus L. leaves extract was significantly greater than that of P. major only and R. dentatus with respect to the removal of carbosulfan from contaminated soil. The contribution of R. dentatus leaves extract to the degradation of carbosulfan in the soil were 20.95%, 18.85%, 5.2% and 1.85% after 2, 4, 8 and 16 days of treatments, respectively. The presence of P. major amended with R. dentatus leaves extract showed significant effect on uptake of carbosulfan into roots at 2 and 4 days, the uptake ratio was about 2.39 and 1.31 times higher compared to P. major alone, respectively. Carbofuran appeared in the P. major roots amended with R. dentatus leaves extract within 2 days of treatment (5.49 mg/kg) and reached the maximum over 8 days (10.19 mg/kg), while carbofuran appeared in the P. major over 4 days of treatment (4.09 mg/kg) and reached the maximum (6.92 mg/kg) over 8 days of exposure. Carbosulfan taken up into P. major leaves reached 4.36 mg/kg over 4 days, while it reached 2.75 mg/kg in P. major leaves amended with R. dentatus leaves extract over the same time. Carbofuran translocated into the P. major leaves amended with R. dentatus leaves extract and reached the maximum over 16 days of exposure (10.43 mg/kg), followed by P. major (9.47 mg/kg) and R. dentatus leaves (9.5 mg/kg), respectively. This study indicates that R. dentatus leaves extract can improve the efficiency of phytoremediation of carbosulfan.

Glyphosate hormesis in broad-leaved weeds: a challenge for weed management

ABSTRACTLittle is known of glyphosate-induced hormesis in weeds and how this might influence weed management. To test the hormetic effect of low doses of glyphosate on broad-leaved weeds, two experiments were conducted, in the laboratory and the screenhouse. The hormetic effects of glyphosate solution in growth media (0, 65, 130, 250, and 500 g acid equivalent (a.e) ha−1) and foliar spray (0, 4, 8, 16, 32, and 64 g a.e. ha−1) were tested on four broad-leaved weeds (Coronopus didymus, Chenopodium album, Rumex dentatus, and Lathyrus aphaca). Glyphosate solution in the range 65–250 g a.e. ha−1 stimulated the germination and seedling growth of all tested weeds. However, at 500 g a.e. ha−1 inhibition of germination and growth was observed. Foliarly applied glyphosate in the range 4–32 g a.e. ha−1 increased root and shoot length, dry biomass, and seed production ability of all four weeds species; however, the stimulatory response was species dependent. These results indicate that glyphosate hormesis could play a significant role in altering crop/weed competition and might influence weed management.

Investigation of the Chemical Composition and Different Effects of a Rumex dentatus Methanol Extract Against Drug Resistant Pseudomonas aeruginosa Isolates

Background: The emergence of Pseudomonas aeruginosa as a multiple drug resistant bacteria has renewed efforts to identify alternative antibacterial materials, such as medicinal plants. Objectives: The aims of this study were to investigate the antibacterial effects of a Rumex dentatus methanol extract against drug resistant P. aeruginosa isolates and to analyze the chemical composition of this extract. Materials and Methods: Sixty strains of P. aeruginosa were isolated from urine and wound samples and identified using conventional tests, as well as 16S rDNA gene sequencing. Results: The isolates were completely resistant to the tested antibiotics, with minimum inhibitory concentration (MIC) values for ceftazidime, imipenem, and gentamicin between 256 to > 256 μg/mL, 8 to > 256 μg/mL, and 64 to > 256 μg/mL, respectively. The R. dentatus extract had a broad spectrum activity against all tested isolates and maximum growth inhibition against isolates from burn wound and urinary tract infections occurred at 200 mg/mL (22.43mm and 22.86mm, respectively). The means of the MIC and minimum bactericidal concentration (MBC) values were 25 and 50 mg/mL, respectively. The effects of a combination of the methanol extract and ceftazidime, imipenem, and gentamicin antibiotics were antagonistic. The GC-MS analysis of the methanol extract revealed a high probable presence percentage of alpha-pinene, sabinene, and eucalyptol (1, 8-cineole) that have confirmed antimicrobial activity. Conclusions: The R. dentatus methanol extract with broad spectrum activity can be viewed as an alternative to antibiotics for treatment of P. aeruginosa infection.

FIRST REPORT OF CRINUM ASIATICUM AS A NATURAL HOST OF TOMATO ZONATE SPOT VIRUS IN CHINA

Crinum asiaticum is a widely grown ornamental in Yun- nan Province (China). Tomato zonate spot virus (TZSV) has been reported to naturally infect solanaeous crops such as tomato (Solanum lycopersicum L.), chili (Capsicum annuum L.), tobacco (Nicotiana tabacum L.) and weeds including Bidens pilosa and Rumex dentatus (Dong et al., 2008, 2010). A survey was conducted in 2013 to identify virus diseases of vegetable crops in Kunming, (Yunnan Province). C. asiati- cum plants showing foliar ringspots and chlorotic spots were collected and investigated. Quasi-spherical and enveloped virions of 80-100 nm in diameter were observed in crude sap from three symptomatic plants by electron microscopy. Indi- rect ELISA of diseased samples showed a positive reaction with an antiserum raised against Tomato zonate spot virus (TZSV) that was produced in our laboratory. To confirm the presence of this virus, total RNA was extracted from ELISA- positive samples of C. asiaticum and used in RT-PCR with the specific primer pair tospoF (5’-ATGTCTAACGTCCG- GAGTTTAAC-3’) and tospoR (5’-TTAAAAAGACAGAT- CATTGCTGCT-3’) designed to amplify the nucleocapsid gene (837 nt). Total RNA from TZSV-infected N. ben- thamiana plants and healthy C. asiaticum plants was used as positive and negative controls, respectively. The RT-PCR products were cloned and sequenced (GenBank accession No. KP684519). BLASTn analysis revealed that the TZSV isolate from C. asiaticum has the highest nucleotide sequence identity (99%) with TZSV isolate T-420 from Iris tectorum (KM452916). To our knowledge, it is the first report of TZSV in C. asiaticum in China.

Effects of the seasonal flooding on riparian soil seed bank in the Three Gorges Reservoir Region: a case study in Shanmu River.

IntroductionThe water-level fluctuation in the Three Gorges Reservoir Region has changed dramatically as a result of the hydroelectric project for flood control and power generation. The riparian seasonal hydrological environment also has changed from summer flooding with winter drought to summer drought with winter flooding. The changes of riparian seed bank and vegetation were investigated to determine the effects of the seasonal flooding on the composition and spatial distribution of riparian soil seed bank and the similarity of seed bank to standing vegetation.Case descriptionWe conducted intensive riparian soil sampling (525 samples) along altitude gradient in the Shanmu River, a tributary of the Yangzi River in the reservoir region of China. Seed bank density, species richness and composition of soil seed bank were examined using the seedling-emergence method. The seasonal hydrological conditions resulted in a decrease in species diversity and an increase in the distribution heterogeneity of the soil seed bank. The soil seed bank was composed of 48 species from 22 families and 40 genera. Most species were annual and perennial herbaceous Polygonaceae, Asteraceae, and Poaceae. Rumex dentatus was the predominant species accounting for 27.0 % of the total seeds. Diversity and composition of the seed bank changed along an altitude gradient and soil depth. Maximum species richness was found in the top soil layer at 165 m and 175 m above sea level. The mean overall seed density of the soil seed bank was 13,475.3 ind m−2. Density and the number of seeds increased initially and then decreased with increased altitude. Maximum seed density (22,500.2 ind m−2) was found at 165 m above sea level in the intermediately flooded riverbank, with the seed number accounting for 27.8 % of the total soil seed bank. Average seed density declined significantly with soil depth. The similarity of seed bank to standing vegetation was relatively high.Discussion and EvaluationThe environmental heterogeneity created by the wide range and seasonal flooding led to the changes in biodiversity and seed density along altitude gradient. The seasonal flooding also led to the increase in the similarity of seed bank to standing vegetation as their composition both degraded.ConclusionsThe seasonal flooding due to the dam reshape the composition and spatial distribution of riparian soil seed bank and limit the vegetation to a grassland dominated by a few annuals and perennials in the Three Gorges Reservoir Region.