Russian Knapweed

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Jorge M. Vivanco - One of the best experts on this subject based on the ideXlab platform.

  • erratum to phytotoxic polyacetylenes from roots of Russian Knapweed acroptilon repens l dc phytochemistry 69 2008 2572 2578
    Phytochemistry, 2009
    Co-Authors: Naira Quintana, Mark W. Paschke, Frank R. Stermitz, Tiffany L. Weir, Corey D. Broeckling, Julie P. Rieder, Jorge M. Vivanco
    Abstract:

    Polyacetylene 3 was said to be the methyl ether of a known alcohol (15 in Bohlmann and Zdero (1970)), but was instead characterized spectroscopically as another isomer. Reassignment of one HMBC correlation now establishes the data and structure into conformity with the Bohlmann/Zdero formulation, depicted below. This also fits 3 into a biosynthetic pattern represented by the other four polyacetylenes isolated. We thank Professor V. Wray for pointing out the discrepancies and for helpful comments. F. Bohlmann and C. Zdero, Uber die inhaltsstoffe aus Eclipta erecta L. Chem Ber. 103 (1970), pp. 834–841. The correct structure, name and NMR spectroscopic assignments for 3 are now given below.

Michael F. Carpinelli - One of the best experts on this subject based on the ideXlab platform.

  • Revegetating Russian Knapweed (Acroptilon Repens) Infestations Using Morphologically Diverse Species and Seedbed Preparation
    Rangeland Ecology & Management, 2007
    Co-Authors: Jane M. Mangold, Clare L. Poulsen, Michael F. Carpinelli
    Abstract:

    Highly degraded pastures and rangeland dominated by Russian Knapweed (Acroptilon repens [L.] DC) are often devoid of desirable plants. Control efforts may be ephemeral because propagules of desirable species are not available to reoccupy niches made available by control procedures. Establishing desirable, competitive plants is essential for enduring management and restoration of Russian Knapweed and other weed-infested plant communities. The objective of this study was to investigate the effectiveness of revegetating Russian Knapweed–infested pastures with 3 nonnative, morphologically diverse species following 1 of 3 seedbed preparation treatments. In successive years, at 2 similar sites in southeastern Oregon, we sprayed Russian Knapweed with glyphosate, then prepared the seedbed by burning, tilling, or leaving untreated. Following seedbed preparation, we seeded a perennial forb (alfalfa [Medicago sativa L.]), a bunchgrass (Siberian wheatgrass [Agropyron fragile {Roth} P. Candargy subsp. sibericum {Willd.} Melderis]), and a sod-forming grass (pubescent wheatgrass [Elytrigia intermedia {Host} Nevski subsp. trichophora {Link} Tvzel]) in monocultures and 2- and 3-species mixtures. We measured Russian Knapweed and seeded-species density 1 and 2 years following seeding. The forb-seeding treatment decreased reinvasion of Russia Knapweed by 50%–60% at 1 site, but otherwise, seeding treatment had little influence on total seeded-species density or Russian Knapweed density. Tilling generally resulted in a 35%–40% reduction in Russian Knapweed density compared with the control and resulted in the highest establishment of seeded species. Variability in annual precipitation appeared to influence seeded-species establishment between the sites. Our results suggest shallow tilling (10–15 cm) followed by drill-seeding desirable forbs and grasses may provide the best results when revegetating Russian Knapweed infestations. Follow-up management should include strategies to enhance desirable species production while minimizing Russian Knapweed reinvasion.

Carpinelli, Michael F. - One of the best experts on this subject based on the ideXlab platform.

  • Revegetating Russian Knapweed (Acroptilon repens) Infestations Using Morphologically Diverse Species and Seedbed Preparation
    'Elsevier BV', 2007
    Co-Authors: Mangold, Jane M., Poulsen, Clare L., Carpinelli, Michael F.
    Abstract:

    Highly degraded pastures and rangeland dominated by Russian Knapweed (Acroptilon repens [L.] DC) are often devoid of desirable plants. Control efforts may be ephemeral because propagules of desirable species are not available to reoccupy niches made available by control procedures. Establishing desirable, competitive plants is essential for enduring management and restoration of Russian Knapweed and other weed-infested plant communities. The objective of this study was to investigate the effectiveness of revegetating Russian Knapweed-infested pastures with 3 nonnative, morphologically diverse species following 1 of 3 seedbed preparation treatments. In successive years, at 2 similar sites in southeastern Oregon, we sprayed Russian Knapweed with glyphosate, then prepared the seedbed by burning, tilling, or leaving untreated. Following seedbed preparation, we seeded a perennial forb (alfalfa [Medicago sativa L.]), a bunchgrass (Siberian wheatgrass [Agropyron fragile {Roth} P. Candargy subsp. sibericum {Willd.} Melderis]), and a sod-forming grass (pubescent wheatgrass [Elytrigia intermedia {Host} Nevski subsp. trichophora {Link} Tvzel]) in monocultures and 2- and 3-species mixtures. We measured Russian Knapweed and seeded-species density 1 and 2 years following seeding. The forb-seeding treatment decreased reinvasion of Russia Knapweed by 50%-60% at 1 site, but otherwise, seeding treatment had little influence on total seeded-species density or Russian Knapweed density. Tilling generally resulted in a 35%-40% reduction in Russian Knapweed density compared with the control and resulted in the highest establishment of seeded species. Variability in annual precipitation appeared to influence seeded-species establishment between the sites. Our results suggest shallow tilling (10-15 cm) followed by drill-seeding desirable forbs and grasses may provide the best results when revegetating Russian Knapweed infestations. Follow-up management should include strategies to enhance desirable species production while minimizing Russian Knapweed reinvasion. The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information.Migrated from OJS platform August 202

Catherine M Aime - One of the best experts on this subject based on the ideXlab platform.

  • life cycle of puccinia acroptili on rhaponticum acroptilon repens
    Mycologia, 2010
    Co-Authors: W L Bruckart, F M Eskandari, D K Berner, Catherine M Aime
    Abstract:

    Russian Knapweed (Rhaponticum repens) is a rangeland weed pest in the western United States. One candidate fungus for biological control of R. repens is Puccinia acroptili, which causes a rust disease. Understanding the life cycle of candidate rust fungi for weed biological control is an essential component in risk assessments and evaluations, and for P. acroptili such was unknown. For this reason greenhouse studies were undertaken to clarify the life cycle of P. acroptili under artificial conditions. Spermogonia with spermatia developed on R. repens following plant inoculation with teliospores. Artificial transfer of spermatia between spermogonia resulted in the development of aecia with uredinioid aeciospores. Inoculation with aeciospores or urediniospores resulted in uredinia containing urediniospores and occasional amphispores. Telia with teliospores and occasional mesospores developed later. Teliospores produced typical basidia with four basidiospores. These results suggest that the life cycle of P. acroptili is macrocyclic and autoecious. Inoculation with teliospores also frequently resulted in production of sori that were morphologically similar to aecia but which were not associated with spermogonia or the classical transfer of spermatia. The ontology of these sori is unknown. This is the first description of spermogonia and the first report and description of basidiospores, aecia, aeciospores, amphispores and mesospores of P. acroptili.

Azam Hatai Hampa - One of the best experts on this subject based on the ideXlab platform.

  • Allelopathic Effects of Sorghum (Sorghum bicolor L.) and Russian Knapweed (Acroptilon repens L.) Aqueous Extract on Seed Germination Indices and Enzyme Activity of Some Field Crops and Weeds
    Ferdowsi University of Mashhad, 2018
    Co-Authors: Azam Hatai Hampa, Abdollah Javanmard, Mohammad Taghi Elebrahim, Omid Sofalian
    Abstract:

    Introduction: The loss of crop yield due to weeds is enormous. Potential yield reductions caused by uncontrolled weed growth throughout a growing season have an estimated range of 45-95%, depending on ecological and climatic conditions. Overusing synthetic herbicides may affect the environmental, human health and food. Furthermore, increasing use of herbicides has resulted in a dramatic increment in the herbicide resistance among weeds, and over 307 weed resistant biotype belonging to 183 species (110 dicots and 73 monocots) have been identified worldwide. Cultivating crops with allelopathic potential can reduce the dependency on synthetic herbicides and increase crop yields. Sorghum (Sorghum bicolor L.) has been reported as one of the most allelopathic crops extensively used as cover and smother crops and also incorporated in the soil for weed suppression. Moreover, Russian Knapweed (Acroptilon repens L.) has been shown to produce phytotoxic compounds and plant growth inhibitors, which may contribute to its competitive behavior. The phenomenon of allelopathy has been suggested to be one of the possible alternatives for achieving sustainable weed management. Materials and Methods: In order to evaluate the allelopathic effects of sorghum (Sorghum bicolor L.) and Russian Knapweed (Acroptilon repens L.) extract on seed germination indices and enzymatic activity of wheat (Triticum aestivum L.), sugar beet (Beta vulgaris L.), common lambsquarters (Chenopodium album L.) and redroot pigweed (Amaranthus retroflexus L.), an experiment was conducted as factorial experiment based on randomized completely design with three replications in Faculty of Agriculture, University of Maragheh in 2016. The investigated factors were four crops (wheat, sugar beet, common lambsquarters and redroot pigweed), shoot aqueous extract (sorghum and Russian Knapweed) and aqueous extract concentrations at 0 (control), 5, 10 and 20% (m/v). Sorghum and Russian Knapweed crops were collected during July 2016. The plants were taken to the laboratory and kept fresh in a refrigerator. In addition, Kato-Noguchi et al., (17) method was followed for extraction. Samples of the above-ground tissues (stems and leaves) of sorghum and Russian Knapweed were washed thoroughly with tap water and rinsed with distilled water. They were clipped and then passed through a 1 mm screen before storage in a refrigerator at 2 ℃. Each 50, 100 and 200 g samples was extracted by soaking it in 1 L of distilled water at 24 ℃ during 24 h in a shaker. All extracts were filtered through two layers of cheese cloth to remove fibers. Distilled water was also considered as the control treatment. Results and Discussion: Results indicated that percentage and rate of germination, radicle and plumule length, radicle dry weight, plumule dry weight, seedling dry weight and vigor length index of all crops decreased significantly by increasing aqueous extract concentration of sorghum and Knapweed. These results are in agreement with those previously reported that the degree of inhibition increased by increasing extract concentration. Using Russian Knapweed aqueous extract, germination percentage was 12.62 percent greater than sorghum aqueous extract. Moreover, inhibitory effect of sorghum aqueous extract on germination rate loss was higher than that of aqueous extract of Russian Knapweed. As to field crops, inhibitory effect of sorghum and Russian Knapweed extract on sugar beet was higher than wheat. Moreover, the effect of sorghum and Knapweed extract on radicle, plumule and seedling fresh weight loss of redroot pigweed and common lambsquarters (weeds) was greater as compared with that on field crops (wheat and sugar beet). Increasing concentration of sorghum extract decreased seed vigor indices of common lambsquarters and redroot pigweed by 83.36 and 87.15% relative to control, respectively. Activity of peroxidase and polyphenoloxidase enzymes was reduced and increased, respectively, as a result of an increment in extract concentration. Batish et al. (7) have demonstrated that parthenin (Parthenium hysterophorus) impairs mung bean growth by affecting respiration, protein content and activities of protease and peroxidase enzymes. The minimum value of plumule and seedling length was observed for redroot pigweed and common lambsquarters weeds with application of 20% aqueous extract of sorghum and Russian Knapweed. The values of weed tolerance index (WTI) revealed that redroot pigweed and common lambsquarters were more sensitive to aqueous extract of sorghum and Russian Knapweed. The WTI combines several individual measured parameters and ranges between 0 and 1. In this case, a low WTI indicates a high susceptibility to biotic or abiotic stress originated from crop extracts. Conclusions: Our results showed that aqueous extracts of sorghum and Russian Knapweed had an inhibitory effect on seed germination indices of wheat, sugar beet, common lambsquarters and redroot pigweed. It can be also concluded that sorghum and Russian Knapweed possess weed-suppressing ability and seem to be useful for developing natural herbicides

  • effect of different concentrations of sorghum and Russian Knapweed water extract on germination characteristics of common lambsquarters and redroot pigweed
    2017
    Co-Authors: Azam Hatai Hampa, Abdollah Javanmard, Solmaz Azizi
    Abstract:

    Most of the allelochemicals are classified as secondary metabolites in plant, are gener rally considered those compounds which do not play any role in primary metabolic processes essential for plants survival. In order to evaluation of allelopathic effects of sorghum (Sorghum bicolor L.) and Russian Knapweed (Acroptilon repens L.) water extract on germination characteristics of common lambsquarters (Chenopodium album L.) and redroot pigweed (Amaranthus retroflexus L.), an experiment was conducted as factorial experiment based on randomized completely design with three replications in Faculty of Agriculture, University of Maragheh in 2016. The factors were included shoot aqueous extract (sorghum and Russian Knapweed) and extract concentrations (control, 5, 10 and 20% m/v). Results indicated that germination daily mean, final germination index, shoot relative growth and root relative growth of redroot pigweed and common lambsquarters decreased significantly with increasing aqueous extract concentration of sorghum and Knapweed. Moreover, inhibitory effect of sorghum aqueous extract on germination loss was higher than Russian Knapweed. The minimum of shoot relative growth of redroot pigweed was seen by application of 20% extract of sorghum and Russian Knapweed. Generally, it can be concluded that sorghum and Russian Knapweed extract have bioherbicidal properties as it causes severe phytotoxicity and interferes with the growth and physiological processes of some weed species.

  • effects of allopathic extract of sorghum and Russian Knapweed on growth and physiological indices of field crops and weeds
    2017
    Co-Authors: Azam Hatai Hampa, Abdollah Javanmard, Hooriye Tavakoli
    Abstract:

    Allelopathic compounds influence biochemical and physiological processes of their adjacent plants. In order to evaluate the response of wheat (Triticum aestivum L.), sugar beet (Beta vulgaris L.), common lambsquarters (Chenopodium album L.) and redroot pigweed (Amaranthus retroflexus L.) to allelopathic effects of shoot aqueous extract of sorghum (Sorghum bicolor L.) and Russian Knapweed (Acroptilon repens L.), a greenhouse experiment as factorial experiment based on randomized completely design with three replications was conducted in Faculty of Agriculture, University of Maragheh in 2016. The factors were included shoot aqueous extract of sorghum and Russian Knapweed and extract concentrations (distilled water as control, 5, 10 and 20% m/v). Results indicated that the highest shoot length of common lambsquarters was seen in control treatment. Also, the lowest of shoot length was observed in redroot pigweed with application of 20% extract concentration. Moreover, chlorophyll a, b and carotenoid decreased significantly with increasing aqueous extract concentration of sorghum and Knapweed. By the way, inhibitory effect of Russian Knapweed extract on chlorophyll a, b and total chlorophyll was more than sorghum extract. From the present study, it could be concluded that sorghum and Russian Knapweed extract show strong phytotoxicity against weeds and hence could be useful for developing as a bioherbicide.