WorldWideScience

Sample records for blackgrass alopecurus myosuroides

  1. Development of herbicide resistance in black-grass (Alopecurus myosuroides in Bavaria

    Directory of Open Access Journals (Sweden)

    Gehring, Klaus

    2016-02-01

    Full Text Available Black-grass (Alopecurus myosuroides is one of the most important grass weeds in Bavaria. Chemical weed control with high efficacy is very important in crops like winter cereals, oilseed rape and maize. Crop rotations with more winter cereals, reduced soil cultivation and e.g. contract harvesting enhanced distribution of blackgrass in arable farming regions. Effects of herbicide resistance were observed since the last 20 years. The blackgrass herbicide resistance is well observed by the official plant protection service of Bavaria. A wide experience of resistance tests shows the development of resistant black-grass and provides an opportunity for future prospects in resistance dynamics.

  2. POLLEN DISPERSAL ABILITIES OF ALS TARGET-SITE RESISTANT BLACK-GRASS (ALOPECURUS MYOSUROIDES HUDS.)

    OpenAIRE

    Maréchal, Pierre-Yves; Henriet, François; Vancutsem, Françoise; Bodson, Bernard

    2011-01-01

    Target-Site Resistant (TSR) black-grass individuals were introduced in a field, at different growing stages to be synchronised with autochthonous population. Patches of susceptible black-grass were created by setting protective canvas on few areas (from 0,5 up to 32m²), during herbicide spraying and they were removed afterwards. Those patches were disposed along rays starting from the introduction point at distances from 2 to 128 meters. In those patches, local black-grass grew regularly and ...

  3. Field studies on the germination behaviour of black-grass (Alopecurus myosuroides Huds. depending on sowing date und winter wheat variety in Northern Germany

    Directory of Open Access Journals (Sweden)

    Landschreiber, Manja

    2014-02-01

    Full Text Available Black-grass (Alopecurus myosuroides, Huds. is the most important herbicide-resistant weed in Europe. In Germany it is not only a problem in the maritime influenced areas like Schleswig-Holstein and Lower Saxony anymore, as well in other regions black-grass develops to the most important weed in winter wheat and oilseed rape. There are multifaceted reasons for that, one reason are close winter crop rotations and early sowing dates which are economically very attractive for the farmers, another one are herbicide resistances. Black-grass germinates in autumn and in spring, but the main germination period is from late August to early October. If winter wheat is sown early in autumn, the main germination is in parallel to the wheat. Then the weeds can only be managed by culture specific herbicides. The pressure on the herbicides is therefore increasing. Herbicide resistances can be the result. As long as very effective herbicides are available, so that farmers are not dependent on weed biology and plant production weed management measures such as sowing date. Late sowing dates can reduce the black-grass populations, but this option is not attractive to many farmers in Schleswig-Holstein. In mind of the farmers the risk of delayed sowing dates in autumn is too high, because increased rainfall such as can make it difficult to marsh soils sowing, or make impossible. Objective of this trial was the germination of Black-grass to show to two sowing dates. The results of the field trial show, that black-grass populations can be reduced if winter wheat is sown later in autumn.

  4. Impact of non-target-site-resistance on herbicidal activity of imazamox on blackgrass (Alopecurus myosuroides Huds. in comparison to other ALS-graminicides

    Directory of Open Access Journals (Sweden)

    Sievernich, Bernd

    2014-02-01

    Full Text Available A black-grass (Alopecurus myosuroides Huds. resistance-monitoring conducted by BASF in 2010 - 2012 revealed a high number of accessions with resistance against imazamox. However, application of imazamoxbased products in a winter crop was limited to winter beans in France and United Kingdom only until the introduction of the Clearfield®-production system in autumn 2012 in winter oilseed rape. It is therefore assumed that the resistance mechanisms were probably selected by the frequent use of ACCase- and ALSinhibitors in winter crop rotations during the last 2 decades. Resistance level for each product-biotype combination was calculated according the “R”-classification system (S, R?, RR, RRR by directly comparing the product performance on a biotype versus untreated control. Majority of resistant biotypes did not show a target-site mutation at the known codon Pro197 or Trp574. In order to better evaluate the impact of Non-Target-Site-Resistance (NTSR on the activity of BEYOND (imazamox, ATLANTIS WG (mesosulfuron+iodosulfuron and ABAK (pyroxsulam, biotypes who have shown an ALS-target-site mutation were removed from further analysis. At the dose rate of 35 g ai/ha BEYOND provided good activity on susceptible biotypes of black-grass almost matching up with ATLANTIS WG and ABAK. However, activity of BEYOND declined stronger on biotypes classified as R? or RR for that product, while ATLANTIS WG and ABAK hardly showed any decline in control on this group of biotypes when applied at the recommended dose rate. It is assumed that the underlying NTSR-mechanism is not effective enough yet to confer resistance to ATLANTIS WG and ABAK, but on BEYOND. In contrast, biotypes classified as R? for ATLANTIS WG did show a stronger impact on the activity of BEYOND and ABAK then of ATLANTIS WG. These differences in control level probably do translate into differences in selection pressure as well.

  5. Spread and control of blackgrass (Alopecurus myosuroides according to an increasing occurrence of resistance - Evaluation of field trials in the federal states Brandenburg, Hessen, Saxony, Saxony-Anhalt and Thuringia in the years 2000 - 2014

    Directory of Open Access Journals (Sweden)

    Meinlschmidt, Ewa

    2016-02-01

    Full Text Available An increasing occurrence of blackgrass (Alopecurus myosuroides with high densities has been reported for Brandenburg, Hessen, Saxony-Anhalt, Saxony and Thuringia. In recent years, an increasing resistance to blackgrass especially to ALS inhibitors and partially to ACCase inhibitors has been reported for some eastern federal states and Hessen, too. It was determined to what extent dicotyledonous weeds are associated with blackgrass. The efficacy of different herbicide applications was tested in field trials between 2000 and 2014. A total of 191 trials have been included in the analysis of blackgrass. Using the HRAC-classification of herbicides tested, combinations of herbicides were used which might contribute to solve problems specifically linked to the detected resistance situation of the site. The study aimed to identify the right timing of the herbicide applications as well as applications as single or serial treatments and the use of herbicide at reduced doses according to the intensity of blackgrass. In autumn, single applications of soil active herbicides were not effective enough, especially at a high density of more than 500 heads of blackgrass per m2. The mixtures of soil active herbicides with leave active herbicides applied in autumn achieved very good control. The herbicide sequences were more effective than single applications. In order to counteract further spread of herbicide resistance, the right choice of the mode of action and highly efficacious herbicide treatments are the methods of choice, of course in addition to nonchemical controlling measures such as delayed autumn drilling, ploughing and crop rotation.

  6. Impact of imazamox containing herbicides on the development of resistance in black-grass (Alopecurus myosuroides Huds.

    Directory of Open Access Journals (Sweden)

    Rosenhauer, Maria

    2014-02-01

    Full Text Available Winter oilseed-rape was the most common crop in Western Europe where no ALS-inhibitor was used. Due to the introduction of Clearfield winter oilseed-rape varieties the use of ALS-inhibitors also in oilseed-rape is possible. If the broader use of ALS-inhibitors increases the selection pressure on herbicide resistant weeds and increases their occurrence in the crop rotation is the question of this investigation. Therefore, an outdoor container trial (á 350 l, 0.7 m² was performed starting in autumn 2011. A typical crop rotation of winter wheat/oilseed-rape/winter wheat was simulated in the following three years. Three different black-grass biotypes with characterised resistance pattern and 5 different herbicide programs were analysed. The blackgrass biotypes showed different target-site resistance against ACCase- and/or ALS-inhibitor, as well as metabolic resistance. Before and after each treatment the numbers of black-grass plants per container were counted. Also the numbers of heads were counted before harvest. Additionally genetic analysis due to PCRs and pyrosequencing of ten survivors per container and year were performed. Till now results of the winter wheat and oilseed-rape cultivation were obtained. Herbicide efficacy was between 77 and 98% for the treatments during the winter wheat cultivation. The genetic analysis showed nearly similar portion of TSR in the black-grass populations when compared with the initial frequencies. Only one container showed no TSR. The comparison of the herbicide programs sprayed during the oilseed-rape cultivation showed the best results for all black-grass biotypes for the application of: Metazachlor + dimethenamid (BBCH 09/10, imazamox + quinmerac + Dash (BBCH 14 and propyzamide (BBCH 21/22.

  7. Impact of imazamox containing herbicides on the development of resistance in black-grass (Alopecurus myosuroides Huds. within an oilseed rape / wheat crop rotation

    Directory of Open Access Journals (Sweden)

    Rosenhauer, Marie

    2016-02-01

    Full Text Available The application of imazamox as an herbicide in oilseed-rape got possible due to the introduction of Clearfield oilseed-rape varieties which are tolerant to ALS inhibitors. The question of this investigation was, if the broader use of ALS-inhibitors increases the selection pressure on herbicide resistant weeds and increases their occurrence in the crop rotation. An outdoor container trial with 30 containers (350 l, 0,7 m² was performed, starting in autumn 2011. A winter wheat – oilseed-rape rotation was simulated for four years. Three different black-grass biotypes with different resistance pattern and 5 different herbicide programmes were analysed in this study in order to investigate the population dynamics of target-site resistance (TSR and the development of metabolic resistance. The trials showed interactions between the black-grass biotype and the herbicide strategy on the increase of the black-grass density. There was no interaction due to the use of propyzamide. The frequency of target-site resistance to ACCase inhibitors increased for the corresponding biotypes independently of the herbicide strategy during the trial period. The low frequency of ALS-TSR at trial start did not change during the trial period, independently of the use of imazamox in the oil-seed rape cultivation. The comparison of the resistance factors between the original biotypes and the seeds harvested after the four year container trial showed increasing resistances against pinoxaden for all biotypes. Within the different black-grass biotypes there was a slightly decrease as well as an increase in imazamox efficacy observed. There was no significant increase of meso- + iodosulfuron resistance compared to the original biotypes from 2011 caused by different herbicide treatments. The results indicated that the integration of imazamox tolerant oilseed rape in winter wheat crop rotations did not necessarily increase the development of herbicide resistant black-grass.

  8. Allelopathy—A Tool to Improve the Weed Competitive Ability of Wheat with Herbicide-Resistant Black-Grass (Alopecurus myosuroides Huds.)

    OpenAIRE

    Nils-Ove Bertholdsson

    2012-01-01

    Controlling black-grass in winter wheat production in northern Europe is an increasing problem because of more frequent winter crops and development of herbicide resistance in weeds. Alternative weed management strategies are needed, e.g., use of more competitive cultivars. Factors that increase cultivar competitiveness include early vigor and straw length, but also allelopathy. Therefore, the allelopathic properties of wheat cultivars included in the Swedish national list or in the release p...

  9. Resistance profile of herbicide-resistant Alopecurus myosuroides (black-grass) populations in Denmark

    DEFF Research Database (Denmark)

    Keshtkar, E.; Mathiassen, S. K; Moss, S. R.;

    2015-01-01

    mutation at the Ile-1781 position. No mutations conferring TSR to ALS inhibitors were detected in the 53 populations. The seed bioassay results showed that all populations had varying degrees of resistance to fenoxaprop-P. In contrast, all populations were susceptible to cycloxydim suggesting that non-target...

  10. Reduction of selection pressure of herbicides - options and limits for blackgrass management by using clethodim in oilseed rape in the presence of the Leu1781 haplotype

    Directory of Open Access Journals (Sweden)

    Wagner, Jean

    2014-02-01

    Full Text Available In field experiments the control of blackgrass (Alopecurus myosuroides, Huds. in oilseed rape using clethodim (Select EC 240 and cycloxydim (Focus Ultra with and without subsequent treatments with propyzamide (Kerb FLO was tested at 6 locations in North and South Germany with assumed resistance problems. The field experiments were accompanied using molecular analysis leaf samples from the plots to seize the occurrence of black-grass with the Leu 1781 haplotype and to determine the frequency of the genotypes. The goal of the trials was to correlate the successes of blackgrass control with the occurrence of hetero- and homozygous resistant genotypes. It was shown in greenhouse trials that clethodim selects the haplotype Leu1781 more weakly (and it shows a higher partial efficacy than cycloxydim and that heterozygous plants have a lower resistance factor than homozygous plants. The question raised whether the frequency of heterozygous plants has influence on increased efficacy of clethodim under field conditions. At 5 sites target-site resistance was detected. At one location the high proportion of heterozygous plants correlated positive with relative higher control using Select EC 240 (80% compared to Focus Ultra (0%. At two locations with high proportion of homozygous resistant plants Select EC 240 and Focus Ultra treatments without subsequent treatments with Kerb FLO were not sufficient in solo variants. The subsequent treatments with Kerb FLO provided partly, but not sufficient control of black-grass. At one location no resistance was identified. The effect of Select EC 240 and Focus Ultra to control black-grass were comparable high in all variants with and without subsequent treatments of Kerb FLO. The investigations showed clearly a higher degree of control by plants with the haplotype Leu1781 by the active substance clethodim and pointed out the fact that the frequency of resistant genotypes (homo vs. heterozygous resistant plants has a

  11. Cadou FORTE – a new herbicide in cereals with efficacy against grasses and dicots

    Directory of Open Access Journals (Sweden)

    Kerlen, Dirk

    2012-03-01

    Full Text Available Cadou FORTE (flufenacet; flurtamone; diflufenican is a new cereal herbicide with efficacy against blackgrass (Alopecurus myosuroides, loose silky-bentgrass (Apera spica-venti L., annual meadow-grass (Poa annua L. and a broad spectrum of dicot weeds. Cadou FORTE can be used in winter wheat, winter barley, winter rye, winter triticale and spelt for pre and post emergence application in autumn. This publication focuses on efficacy trials from three years of autumn application with Cadou FORTE.

  12. Atlantis Star – a new herbicide in cereals with efficacy against grasses and dicots

    OpenAIRE

    Kerlen, Dirk; Naunheim, Peter

    2016-01-01

    Atlantis Star (mesosulfuron-methyl; iodosulfuron-methyl-sodium; thiencarbazone-methyl; mefenpyr-diethyl) is a new cereal herbicide to control blackgrass (Alopecurus myosuroides; sensitive and high infestation), brome grass (Bromus spec.), ryegrass (Lolium spec.), wild oat (Avena fatua), loose silky-bentgrass (Apera spica-venti L.), annual meadow-grass (Poa annua L.) and dicot weeds. Atlantis Star can be used in winter wheat, winter triticale, winter rye, winter durum wheat and spelt. The p...

  13. First report of Alopecurus arundinaceus, A. myosuroides, Hordeum violaceum and Phleum pratense as hosts of Claviceps purpurea population G2 in Turkey

    Czech Academy of Sciences Publication Activity Database

    Eken, C.; Pažoutová, Sylvie; Honzátko, Aleš; Yildiz, S.

    2006-01-01

    Roč. 88, č. 1 (2006), s. 121-125. ISSN 1125-4653 Institutional research plan: CEZ:AV0Z50200510 Keywords : ergot * c. purpurea * erzurum Subject RIV: EE - Microbiology, Virology Impact factor: 0.783, year: 2006

  14. Atlantis Star – a new herbicide in cereals with efficacy against grasses and dicots

    Directory of Open Access Journals (Sweden)

    Kerlen, Dirk

    2016-02-01

    Full Text Available Atlantis Star (mesosulfuron-methyl; iodosulfuron-methyl-sodium; thiencarbazone-methyl; mefenpyr-diethyl is a new cereal herbicide to control blackgrass (Alopecurus myosuroides; sensitive and high infestation, brome grass (Bromus spec., ryegrass (Lolium spec., wild oat (Avena fatua, loose silky-bentgrass (Apera spica-venti L., annual meadow-grass (Poa annua L. and dicot weeds. Atlantis Star can be used in winter wheat, winter triticale, winter rye, winter durum wheat and spelt. The publication is based on efficacy trials from two years of spring application with Atlantis Star.

  15. Atlantis FLEX (BAY 22010 H – a new herbicide in cereals with efficacy against grasses

    Directory of Open Access Journals (Sweden)

    Kerlen, Dirk

    2014-02-01

    Full Text Available Atlantis FLEX (Mesosulfuron-methyl; Propoxycarbazone-sodium; Mefenpyr-diethyl is a new cereal herbicide to control blackgrass (Alopecurus myosuroides, ryegrass (Lolium spec., brome grass (Bromus spec., wild oat (Avena fatua, loose silky-bentgrass (Apera spica-venti L, annual meadow-grass (Poa annua L. and dicot weeds. Atlantis FLEX can be used in winter wheat, winter triticale, winter rye, winter durum wheat and spelt. The publication is based on efficacy trials from two years of spring application with Atlantis FLEX. It will be shown, that Atlantis FLEX generates a good to excellent efficacy against grass-weeds.

  16. Interaction of pre- and post-emergence herbicide treatment on efficacy of different black-grass biotypes with enhanced metabolism

    OpenAIRE

    Petersen, Jan; Olf, Florian

    2014-01-01

    In an outdoor container trial with different resistant black-grass biotypes with enhanced metabolism, efficacy of pre- and post-emergence treatments as well as their sequence was investigated in spring wheat. Weed control success was compared to a susceptible biotype. Results indicate that there are strong interactions between herbicide and black-grass biotypes. As a consequence site specific herbicide strategies corresponding to current herbicide resistance situation can be necessary. If fur...

  17. Interaction of pre- and post-emergence herbicide treatment on efficacy of different black-grass biotypes with enhanced metabolism

    Directory of Open Access Journals (Sweden)

    Petersen, Jan

    2014-02-01

    Full Text Available In an outdoor container trial with different resistant black-grass biotypes with enhanced metabolism, efficacy of pre- and post-emergence treatments as well as their sequence was investigated in spring wheat. Weed control success was compared to a susceptible biotype. Results indicate that there are strong interactions between herbicide and black-grass biotypes. As a consequence site specific herbicide strategies corresponding to current herbicide resistance situation can be necessary. If further trials support these findings than it is essential to characterize the site specific herbicide resistance situation and the potential interactions between different biotypes x herbicides resp. sequences. Only under these circumstances it is possible to optimize the herbicide choice on a specific site. Black-grass control might be optimal than and further speed of resistance evolution might be reduced on that site.

  18. GWN-3189 B – A new selective herbicide based on Triallate for control of herbicide resistant grass weed in cereals

    Directory of Open Access Journals (Sweden)

    Mühlschlegel, Friedrich

    2014-02-01

    Full Text Available With substantial work on the formulation, Gowan offers a new herbicide (GWN-3189 B based on Triallate for use on winter wheat, winter barley, winter rye, winter triticale and spring barley. GWN-3189B will be applied from pre-emergence to early post-emergence of the crop and offers a broad spectrum against grass-weeds. GWN-3189 B is selective on all cereal species. As soil herbicide GWN-3189 B offers interesting alternatives in grass-weed resistance management. The efficacy on grass weed, especially on Alopecurus myosuroides (blackgrass, Apera spica venti (silky bentgrass and Lolium multiflorum (italian ryegrass is demonstrated with results of field trials performed in France, Great Britain and Germany.

  19. Diversifying cereal-based rotations to improve weed control. Evaluation with the AlomySys model quantifying the effect of cropping systems on a grass weed

    Directory of Open Access Journals (Sweden)

    Colbach Nathalie

    2010-09-01

    Full Text Available Simplified rotations often select weed flora consisting of one or several dominant species. In rotations consisting mainly of winter cereals, one of the most frequent weeds in Atlantic European countries is blackgrass (Alopecurus myosuroides Huds.. In order to reduce environmental impacts and avoid the selection of herbicide-resistant populations, alternative weed management strategies are necessary. The objective of the present study was to develop a methodology for using a weed dynamics model called ALOMYSYS for evaluating prospective diversified crop rotations based on expert opinion. These prospective rotations were developed for a particular region aiming at reducing herbicide use while keeping weed infestation similar to that in current cropping systems. The prospective systems were also evaluated economically by calculating costs and margins for the farmer. The simulations showed that the more diverse the rotation, the better blackgrass was controlled and the less herbicides (rates and frequencies were necessary. Optimal herbicide spraying conditions and mouldboard ploughing were also less essential in diverse rotations. It was though essential to reason herbicide programs over the whole rotation and not simply as function of the preceding crop. The economic evaluation identified the interest of spring or winter pea either replacing or preceding oilseed rape (OSR in OSR/wheat/barley rotations.

  20. Distribution of endophytic bacteria in Alopecurus aequalis Sobol and Oxalis corniculata L. from soils contaminated by polycyclic aromatic hydrocarbons.

    Directory of Open Access Journals (Sweden)

    Anping Peng

    Full Text Available The distributions of endophytic bacteria in Alopecurus aequalis Sobol and Oxalis corniculata L. grown in soils contaminated with different levels of polycyclic aromatic hydrocarbons (PAHs were investigated with polymerase chain reaction followed by denaturing gradient gel electrophoresis technology (PCR-DGGE and cultivation methods. Twelve types of PAHs, at concentrations varying from 0.16 to 180 mg·kg(-1, were observed in the roots and shoots of the two plants. The total PAH concentrations in Alopecurus aequalis Sobol obtained from three different PAH-contaminated stations were 184, 197, and 304 mg·kg(-1, and the total PAH concentrations in Oxalis corniculata L. were 251, 346, and 600 mg·kg(-1, respectively. The PCR-DGGE results showed that the endophytic bacterial communities in the roots and shoots of the two plants were quite different, although most bacteria belonged to Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes. A total of 68 endophytic bacterial strains were isolated from different tissues of the two plants and classified into three phyla: Firmicutes, Proteobacteria and Bacteroidetes. In both plants, Bacillus spp. and Pseudomonas spp. were the dominant cultivable populations. With an increase in the PAH pollution level, the diversity and distribution of endophytic bacteria in the two plants changed correspondingly, and the number of cultivable endophytic bacterial strains decreased rapidly. Testing of the isolated endophytic bacteria for tolerance to each type of PAH showed that most isolates could grow well on Luria-Bertani media in the presence of different PAHs, and some isolates were able to grow rapidly on a mineral salt medium with a single PAH as the sole carbon and energy source, indicating that these strains may have the potential to degrade PAHs in plants. This research provides the first insight into the characteristics of endophytic bacterial populations under different PAH pollution levels and provides a

  1. BIOLOGICAL COEFFICIENTS OF PHYTOREMEDIATION OF SOIL EXPOSED TO LEAD AND CADMIUM AND USING ALOPECURUS MAGELLANICUS BRACTEATUS AND MUHLENBERGIA ANGUSTATA (POACEAE), PUNO, PERU

    OpenAIRE

    Argota-Perez, G.; Encinas-Cáceres, M.; Argota-Coello, H.; Iannacone, J.

    2014-01-01

    The aim of this study was to determine the biological coefficients of phytoremediation in soils of mine tailings for comparable exposure to Pb and Cd, using Alopecurus magellanicus bracteatus and Muhlenbergia angustata (Poaceae) Ananea, Puno, Peru. Between March and August 2013, ten points of sampling were selected next to a mining area of Ananea -Puno, Peru. The metals analyzed were quantified by inductively coupled plasma spectrometry. To evaluate the potential of phytoremediati...

  2. The influence of nitrogen in stemflow and precipitation on epiphytic bryophytes, Isothecium myosuroides Brid., Dicranum scoparium Hewd. and Thuidium tamariscinum (Hewd.) Schimp of Atlantic oakwoods

    Energy Technology Data Exchange (ETDEWEB)

    Leith, I.D. [Centre for Ecology and Hydrology Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 0QB (United Kingdom)], E-mail: idl@ceh.ac.uk; Mitchell, R.J.; Truscott, A.-M. [Centre for Ecology and Hydrology Banchory, Hill of Brathens, Banchory, Aberdeenshire, AB31 4BW (United Kingdom); Cape, J.N.; Dijk, N. van; Smith, R.I.; Fowler, D.; Sutton, M.A. [Centre for Ecology and Hydrology Edinburgh, Bush Estate, Penicuik, Midlothian, EH26 0QB (United Kingdom)

    2008-09-15

    The spatial relationship between the concentration and deposition of the major ions in precipitation and stemflow and their influence on the tissue nitrogen concentration of three epiphytic bryophytes on Quercus petraea (Matt) Liebl. and Q. robur L. was investigated at seven UK Atlantic oak woodland sites with a range of total N deposition of 55-250 mmol m{sup -2}. The main driver of change in tissue N concentrations of three epiphytic bryophytes (Isothecium myosuroides Brid. (Eurhynchium myosuroides (Brid.) Schp.), Dicranum scoparium Hewd. and Thuidium tamariscinum (Hewd.) Schimp.) was total N deposition in stemflow, dominated by ammonium deposition. The three epiphytic species also showed strong relationships between tissue N concentration and total N deposition in rainfall but a poor correlation with total N ion concentration in rainfall. This study shows that epiphytic bryophytes utilise stemflow N and thus increase their risk from inputs of total N deposition compared to terricolous species at the same site. - Stemflow increases the tissue N concentration of epiphytic bryophytes.

  3. The influence of nitrogen in stemflow and precipitation on epiphytic bryophytes, Isothecium myosuroides Brid., Dicranum scoparium Hewd. and Thuidium tamariscinum (Hewd.) Schimp of Atlantic oakwoods

    International Nuclear Information System (INIS)

    The spatial relationship between the concentration and deposition of the major ions in precipitation and stemflow and their influence on the tissue nitrogen concentration of three epiphytic bryophytes on Quercus petraea (Matt) Liebl. and Q. robur L. was investigated at seven UK Atlantic oak woodland sites with a range of total N deposition of 55-250 mmol m-2. The main driver of change in tissue N concentrations of three epiphytic bryophytes (Isothecium myosuroides Brid. (Eurhynchium myosuroides (Brid.) Schp.), Dicranum scoparium Hewd. and Thuidium tamariscinum (Hewd.) Schimp.) was total N deposition in stemflow, dominated by ammonium deposition. The three epiphytic species also showed strong relationships between tissue N concentration and total N deposition in rainfall but a poor correlation with total N ion concentration in rainfall. This study shows that epiphytic bryophytes utilise stemflow N and thus increase their risk from inputs of total N deposition compared to terricolous species at the same site. - Stemflow increases the tissue N concentration of epiphytic bryophytes

  4. Validation of the chlorophyll fluorescence imaging method (CFI for early detection of herbicide resistance in weeds

    Directory of Open Access Journals (Sweden)

    Menegat, Alexander

    2014-02-01

    Full Text Available The increasing number of herbicide tolerant weed populations is illustrating the increasing demand for reliable methods for an accelerated detection of herbicide tolerance compared to greenhouse studies. Several methods for resistance quick detection have been published in previous years. One of the recent methods is the Chlorophyll Fluorescence Imaging Method (CFI. For this method changes in photosynthetic activity of the target organisms, caused by herbicides, are determined. General assumption of this method in terms of herbicide resistance detection is that each herbicidal compound, independent of the mode of action, will cause changes within the photosynthetic apparatus of the target organisms. This effect already could be confirmed for several modes of action (PSII, ALS, ACCase, EPSPS, synth. Auxins. Aim of this study is to validate this novel method on the basis of greenhouse experiments and single nucleotide polymorphisms (SNP analysis. The resistance profiles of 10 black-grass populations (Alopecurus myosuroides Huds. have been determined in greenhouse herbicide efficacy trials and constitutive SNP analyses of the survivors. With the CFI-method it was possible to detect the resistance profile as well as the resistance frequency within the populations. The results from the greenhouse experiments could be reproduced with conformity of 94%. This result is valid for the tested herbicides mesosulfuron, pyroxsulam as well as clodinafop and pinoxaden.

  5. Within-species variation in grass weeds in Sweden

    OpenAIRE

    Espeby Åkerblom, Liv

    2010-01-01

    Variation within a weed species enables it to persist through varying conditions and is thus an important component of weediness. In this thesis, intra-specific variation in two agronomically important attributes - herbicide susceptibility and seed dormancy - are studied in Swedish Apera spica-venti (L.) Beauv. and Alopecurus myosuroides Huds., both serious annual weeds in winter cereals, and with many cases of herbicide resistance. Swedish Elymus repens (L.) Gould, a perennial, rhizomatous g...

  6. Détection de résistances aux inhibiteurs de l'ALS : des outils moléculaires pour un diagnostic rapide et fiable

    OpenAIRE

    Délye, Christophe; Boucansaud, Karelle; Pernin, Fanny; Couloume, B.

    2008-01-01

    Les inhibiteurs de l’acétolactate-synthase (ALS) sont une des classes d’herbicides les plus utilisées actuellement. Être capable de diagnostiquer rapidement la présence de plantes résistantes à ces substances contribue à maintenir leur efficacité. La plupart des cas de résistance aux inhibiteurs de l’ALS sont dus à des mutations dans le gène de l’ALS. Des tests moléculaires ont été développés chez les principales graminées adventices du blé, le Vulpin (Alopecurus myosuroides) et les Ivraies (...

  7. New xenophytes from Gran Canaria (Canary Islands, Spain, with emphasis on naturalized and (potentially invasive species

    Directory of Open Access Journals (Sweden)

    Verloove, F.

    2013-12-01

    Full Text Available Trabajos recientes de campo en Gran Canaria han facilitado el descubrimiento de nuevas localidades para plantas vasculares no nativas. Agave attenuata, Antigonon leptopus, Atriplex nummularia, Cascabela thevetia, Cenchrus echinatus, Cuscuta campestris, Diplachne fusca subsp. uninervia, Diplotaxis tenuifolia, Dysphania anthelmintica (hasta ahora confundida con D. ambrosioides, Eclipta prostrata, Euphorbia pulcherrima, Fagopyrum esculentum, Gossypium barbadense, Lablab purpureus, Lemna minuta, Opuntia leucotricha, Passiflora edulis, Pennisetum glaucum, Phaseolus acutifolius, Pluchea carolinensis, Prosopis juliflora, Salvia microphylla, Schinus terebinthifolius, Senna spectabilis, Solanum chrysotrichum, Tecoma stans, Tipuana tipu, Urochloa mutica, U. plantaginea y Washingtonia se citan por primera vez para las Islas Canarias, mientras que Alopecurus myosuroides, Amaranthus blitoides, Bothriochloa ischaemum var. songarica, Cardamine flexuosa subsp. debilis, Heliotropium curassavicum, Leonotis nepetifolia, Medicago lupulina, Parkinsonia aculeata, Physalis peruviana, Phytolacca americana y Turnera ulmifolia son nuevas para la flora de la isla de Gran Canaria. Finalmente, se confirma la presencia de Paspalum vaginatum, P. distichum y Cortaderia selloana en Gran Canaria.Trabajos recientes de campo en Gran Canaria han facilitado el descubrimiento de nuevas localidades para plantas vasculares no nativas. Agave attenuata, Antigonon leptopus, Atriplex nummularia, Cascabela thevetia, Cenchrus echinatus, Cuscuta campestris, Diplachne fusca subsp. uninervia, Diplotaxis tenuifolia, Dysphania anthelmintica (hasta ahora confundida con D. ambrosioides, Eclipta prostrata, Euphorbia pulcherrima, Fagopyrum esculentum, Gossypium barbadense, Lablab purpureus, Lemna minuta, Opuntia leucotricha, Passiflora edulis, Pennisetum glaucum, Phaseolus acutifolius, Pluchea carolinensis, Prosopis juliflora, Salvia microphylla, Schinus terebinthifolius, Senna spectabilis, Solanum

  8. A comparative study of drug resistance mechanism associated with active site and non-active site mutations: I388N and D425G mutants of acetyl-coenzyme-A carboxylase.

    Science.gov (United States)

    Zhu, Xiao-Lei; Yang, Guang-Fu

    2012-03-01

    A major concern in the development of acetyl-CoA carboxylase-inhibiting (ACCase; EC 6.4.1.2) herbicides is the emergence of resistance as a result of the selection of distinct mutations within the CT domain. Mutations associated with resistance have been demonstrated to include both active sites and non-active sites, including Ile-1781-Leu, Trp- 2027-Cys, Ile-2041-Asn, Asp-2078-Gly, and Gly-2096-Ala (numbered according to the Alopecurus myosuroides plastid ACCase). In the present study, extensive computational simulations, including molecular dynamics (MD) simulations and molecular mechanics-Poisson-Boltzmann surface area (MM/PBSA) calculations, were carried out to compare the molecular mechanisms of active site mutation (I388N) and non-active site mutation (D425G) in Alopecurus myosuroides resistance to some commercial herbicides targeting ACCase, including haloxyfop (HF), diclofop (DF) and fenoxaprop (FR). All of the computational model and energetic results indicated that both I388N and D425G mutations have effects on the conformational change of the binding pocket. The π-π interaction between ligand and Phe377 and Tyr161' residues, which make an important contribution to the binding affinity, was decreased after mutation. As a result, the mutant-type ACCase has a lower affinity for the inhibitor than the wild-type enzyme, which accounts for the molecular basis of herbicidal resistance. The structural and mechanistic insights obtained from the present study will deepen our understanding of the interactions between ACCase and herbicides, which provides a molecular basis for the future design of a promising inhibitor with low resistance risk. PMID:22242795

  9. RESISTANCE TO ALS-INHIBITING HERBICIDES IN WEED POPULATIONS FROM BELGIAN WHEAT FIELDS.

    Science.gov (United States)

    S, Claerhout; B, De Cauwer

    2015-01-01

    In modern agriculture, most farmers rely on herbicides for weed control. The intensive use of herbicides in crops has led to the development of herbicide resistance in numerous weeds worldwide. In Belgium, farmers have encountered problems with controlling populations of Alopecurus myosuroides, Matricaria recutita, Stellaria media and Popover rhoeas in some wheat fields with the conventionally used acetolactate synthase (ALS)-inhibiting herbicides. Dose response assays were conducted in the greenhouse to test the sensitivity of these populations to the key ALS-inhibiting herbicides mesosulfuron-methyl + iodosulfuron-methyl for A. myosuroides and metsulfuron-methyl and florasulam for M. recutita, S. media and P. rhoeas. The ED₉₀- and ED₅₀-values (effective dose for resp. 90% and 50% biomass reduction) were compared with those of sensitive reference populations and the resistance index (RI) was calculated. High levels of resistance were detected forA. myosuroides (RI: 24.3) after treatment with mesosulfuron-methyl and for M. recutita (RI: 36.4 to 49.5), S. media (RI > 20) and P. rhoeas (RI: 23.6) after treatment with metsulfuron-methyl. However, the metsulfuron-methyl resistant populations of M. recutita and S. media were sufficiently controlled with florasulam at the maximum authorised field dose. This was not the case for P. rhoeas. The metsulfuron-methyl resistant P. rhoeas population were also high-level resistant against florasulam (RI: 29.5). Integrated weed management practices (crop rotation, herbicide mixing, ...) should be applied to reduce the selection pressure for resistant weeds. PMID:27145589

  10. Determination of ploidy level and isolation of genes encoding acetyl-CoA carboxylase in Japanese Foxtail (Alopecurus japonicus.

    Directory of Open Access Journals (Sweden)

    Hongle Xu

    Full Text Available Ploidy level is important in biodiversity studies and in developing strategies for isolating important plant genes. Many herbicide-resistant weed species are polyploids, but our understanding of these polyploid weeds is limited. Japanese foxtail, a noxious agricultural grass weed, has evolved herbicide resistance. However, most studies on this weed have ignored the fact that there are multiple copies of target genes. This may complicate the study of resistance mechanisms. Japanese foxtail was found to be a tetraploid by flow cytometer and chromosome counting, two commonly used methods in the determination of ploidy levels. We found that there are two copies of the gene encoding plastidic acetyl-CoA carboxylase (ACCase in Japanese foxtail and all the homologous genes are expressed. Additionally, no difference in ploidy levels or ACCase gene copy numbers was observed between an ACCase-inhibiting herbicide-resistant and a herbicide-sensitive population in this study.

  11. Validation of a set of reference genes to study response to herbicide stress in grasses

    Directory of Open Access Journals (Sweden)

    Petit Cécile

    2012-01-01

    Full Text Available Abstract Background Non-target-site based resistance to herbicides is a major threat to the chemical control of agronomically noxious weeds. This adaptive trait is endowed by differences in the expression of a number of genes in plants that are resistant or sensitive to herbicides. Quantification of the expression of such genes requires normalising qPCR data using reference genes with stable expression in the system studied as internal standards. The aim of this study was to validate reference genes in Alopecurus myosuroides, a grass (Poaceae weed of economic and agronomic importance with no genomic resources. Results The stability of 11 candidate reference genes was assessed in plants resistant or sensitive to herbicides subjected or not to herbicide stress using the complementary statistical methods implemented by NormFinder, BestKeeper and geNorm. Ubiquitin, beta-tubulin and glyceraldehyde-3-phosphate dehydrogenase were identified as the best reference genes. The reference gene set accuracy was confirmed by analysing the expression of the gene encoding acetyl-coenzyme A carboxylase, a major herbicide target enzyme, and of an herbicide-induced gene encoding a glutathione-S-transferase. Conclusions This is the first study describing a set of reference genes (ubiquitin, beta-tubulin and glyceraldehyde-3-phosphate dehydrogenase with a stable expression under herbicide stress in grasses. These genes are also candidate reference genes of choice for studies seeking to identify stress-responsive genes in grasses.

  12. Analysis of spray retention on a 3D black-grass plant model as a function of spray nozzle and formulation using a process-driven approach

    OpenAIRE

    Massinon, Mathieu; Ouled Taleb Salah, Sofiene; Dumont, Benjamin; Lebeau, Frédéric

    2014-01-01

    The efficiency of spray application of foliar plant protection products can be variable because of the different amount of spray solution intercepted and retained by leaves. On one hand, the spray interception by plants is affected by nozzle kind, size and operating pressure as well as by the plant architecture. On the other hand, the spray retention is affected by application parameters resulting from droplet size and velocity as well as spray mixture physicochemical properties. In this pape...

  13. Milestone – a selective herbicide for the control of important grasses and broadleaved weeds in winter oilseed rape

    Directory of Open Access Journals (Sweden)

    Zotz, Agnes

    2016-02-01

    Full Text Available MilestoneTM herbicide contains the active substance propyzamide (500 g/L and aminopyralid (5.3 g a.e./L and is formulated as a suspension concentrate (SC. Registration for Milestone for the use in winter oilseed rape was granted in Germany in July 2014. The active substance propyzamide is well known from the product KerbTM FLO (containing 500 g/L propyzamide, suspension concentrate, SC which is widely used in winter oilseed rape (WITTROCK et al., 2008. Aminopyralid is formulated in the commercial product Runway (clopyralid + picloram + aminopyralid. Milestone is applied with a use rate of 1.5 L/ha as a post-emergence herbicide from growth stage BBCH 14 of the crop at the beginning of November until February. Kerb FLO is applied with a use rate of 1.875 L/ha at the same timing. The efficacy of Milestone and Kerb FLO was tested in randomised and replicated plot trials in Germany, France and the United Kingdom. Milestone and Kerb FLO showed comparable and very high control levels against monocotyledonous species such as Alopecurus myosuroides, Apera spica-venti, Bromus species and volunteer cereals. Milestone shows a broader spectrum of activity vs. Kerb FLO against dicotyledonous weeds such as Matricaria chamomilla, Papaver rhoeas and Centaurea cyanus. The use of Milestone in dense crops (as the situation was in autumn 2014 for many areas in Germany shows very high efficacy levels as well. The comparison of various application timings between end of October until beginning of December confirms the application date early November for best results. Milestone controls herbicide-resistant weed populations and can be considered an important part of a resistance management program not only in winter oilseed rape but as a component of an integrated weed management strategy in cropping systems.

  14. Recent changes of arable weeds flora and management as a basis for future adaptations

    Directory of Open Access Journals (Sweden)

    Breitsameter, Laura

    2014-02-01

    Full Text Available In the course of the past decennia, numerous shifts of the arable weeds flora have been observed as a result of climate change and of changes of land use and agricultural management practice. These shifts necessitate appropriate adaptations of weed management. The present study depicts alterations of the arable weeds flora of Lower Saxony based on data from two different sources, and describes recent changes of arable weeds management. We firstly conducted a questionnaire-based survey among plant protection consultants and experts of agronomy and plant protection in industry and the federal agriculture authorities. This survey was aimed at identifying which weed taxa have gained or lost relevance for management, and which tendencies with regard to their relevance is expected according to expert knowledge. In addition, the experts were asked for information on possible adaptations and challenges of weed management expected for the future. Secondly, we used protocols of plant protection trails published by the Lower Saxony chamber of agriculture in order to determine alterations of the weed management practice since the 1980s. The screened data gave a clear indication of an increase of the relevance during the past 30 years for a number of weed taxa, in particular for several millet taxa, Geranium species, Alopecurus myosuroides and Chenopodium album. In the evaluation of changes of the relevance of individual weed taxa, the impact of climate change cannot be segregated from effects of altered agricultural practices, which are in turn themselves influenced by climate change. Records of the agricultural practice have pointed out shifts in herbicide application dates which parallel altered sowing dates, e. g., an increase in the frequency of herbicide application in autumn rather than in spring for winter wheat. The recent shifts of weed flora and management practices can serve as a basis for the development of management adaptations for the future

  15. Flora survey on extensive meadows of selected area near Kobilje

    OpenAIRE

    Lainšček, Tadej

    2016-01-01

    Between the years 2009 and 2013, we mapped 273 different taxons on 70 polygones in extensively used grasslands near Kobilje village in Prekmurje. Amongs those taxons, there are 43 nature conservation important species: Achillea ptarmica, Alnus glutinosa, Alopecurus aequalis, Alopecurus pratensis, Carex acutiformis, C. appropinquata, C. canescens, C. tomentosa, C. umbrosa, C. vesicaria, Cerastium glutinosum, Clematis recta, Convallaria majalis, Dianthus carthusianorum, D. deltoides, D. superbu...

  16. Allergen identification in 5 grasses by means of crossed radioimmunoelectrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Diener, C.; Skibbe, K.; Jaeger, L. (Friedrich-Schiller-Universitaet, Jena (German Democratic Republic))

    1984-01-01

    Using crossed radioimmunoelectrophoresis aqueous extracts from pollen of Phleum pratense, Lolium perenne, Poa pratensis, Festuca pratensis and Alopecurus pratensis were investigated for allergen composition. Between 24 and 32 antigens were detected. Employing sera from 11 patients with well established hay fever, IgE binding could be demonstrated in 15 out of 28 antigens in Phleum pratense, 13 out of 32 in Lolium perenne, 14 out of 26 in Poa pratensis, 12 out of 24 Festuca pratensis and 12 out of 24 antigens in Alopecurus pratensis. The 11 patients showed an individual pattern of sensitization against the various pollen allergens.

  17. The influence of mountain meadow management on the occurence of Puccinia perplexans Plow

    Czech Academy of Sciences Publication Activity Database

    Voženílková, B.; Marková, J.; Klimeš, F.; Květ, Jan; Mašková, Z.

    2008-01-01

    Roč. 115, č. 4 (2008), s. 167-171. ISSN 1861-3829 R&D Projects: GA ČR(CZ) GA206/99/1410 Institutional research plan: CEZ:AV0Z60870520 Keywords : Alopecurus pratensis * fallow stand * mown stand * mulched stand * rust fungi Subject RIV: EF - Botanics Impact factor: 0.566, year: 2008

  18. Aportaciones a la flora del Sistema Ibérico meridional

    OpenAIRE

    García Cardo, O.

    2006-01-01

    Se comentan 45 táxones de plantas vasculares nuevas o poco conocidas para las provincias de Cuenca, Guadalajara y Teruel. Merecen destacarse las primeras citas de Alopecurus aequalis, Armeria arenaria subsp. bilbilitana, Avenula pubescens, Elatine alsinastrum, Gnaphalium uliginosum, Juncus bulbosus, Myosotis laxa subsp. caespitosa, Sedum nevadense, Tribulus terrestris y Viola parvula en la provincia de Cuenca y Potentilla anserina en las de Cuenca y Teruel.

  19. Ultrastructure and Development of Anthracoidea Elynae Ustilospores

    Directory of Open Access Journals (Sweden)

    Marcel PARVU

    2009-06-01

    Full Text Available The aim of the study was to examine the ultrastructure of Anthracoidea elynae ustilospores isolated from Kobresia myosuroides (Vill. Fiori plant ovaries, harvested in the Bucegi Mountains, Romania. Samples examination was performed using scanning (SEM and transmission (TEM electron microscopy. The results showed that A. elynae ustilospores had a dynamic ultrastructure, because their three-layered cell wall, nucleus shape, lipid and glycogen accumulations in the cytoplasm changed at each developmental stage. In conclusion, according to the ultrastructural changes, A. elynae ustilospores development may be divided into three stages.

  20. Increasing efficacy of graminicides with a forward angled spray

    DEFF Research Database (Denmark)

    Jensen, Peter Kryger

    2012-01-01

    Control of annual grass species with vertically oriented leaves in agricultural crops by application of foliar acting herbicides with conventional hydraulic sprayers can be increased using forward angled nozzles. Changing the spray angle from the normally predominantly vertical spray towards...... efficacy on L. perenne at early growth stages using nozzles with different spray quality, at different driving speeds and in different wind conditions. Similarly graminicide efficacy was increased when nozzles were angled 60° forward controlling A. myosuroides. Experiments investigating control of the two...

  1. Diversity and distribution of 16S rRNA and phenol monooxygenase genes in the rhizosphere and endophytic bacteria isolated from PAH-contaminated sites

    OpenAIRE

    Anping Peng; Juan Liu; Wanting Ling; Zeyou Chen; Yanzheng Gao

    2015-01-01

    This is the first investigation of the diversity and distribution of 16S rRNA and phenol monooxygenase (PHE) genes in endophytic and rhizosphere bacteria of plants at sites contaminated with different levels of PAHs. Ten PAHs at concentrations from 34.22 to 55.29 and 45.79 to 97.81 mg·kg−1 were measured in rhizosphere soils of Alopecurus aequalis Sobol and Oxalis corniculata L., respectively. The diversity of 16S rRNA and PHE genes in rhizosphere soils or plants changed with varying PAH pollu...

  2. Root discrimination of closely related crop and weed species using FT MIR-ATR spectroscopy

    Directory of Open Access Journals (Sweden)

    Catharina eMeinen

    2015-09-01

    Full Text Available Root discrimination of species is a pre-condition for studying belowground competition processes between crop and weed species. In this experiment, we tested Fourier transform mid-infrared (FT MIR-attenuated total reflection (ATR spectroscopy to discriminate roots of closely related crop and weed species grown in the greenhouse: maize/barnyard grass, barley/wild oat, wheat/blackgrass (Poaceae, and sugar beet/common lambsquarters (Chenopodiaceae. Fresh (moist and dried root segments as well as ground roots were analyzed by FT MIR-ATR spectroscopy. Root absorption spectra showed species specific peak distribution and peak height. A clear separation according to species was not possible with fresh root segments. Dried root segments (including root basis, middle section and root tip of maize/barnyard grass and sugar beet/common lambsquarters formed completely separated species clusters. Wheat and blackgrass separated in species specific clusters when root tips were removed from cluster analysis. A clear separation of dried root segments according to species was not possible in the case of barley and wild oat. Cluster analyses of ground roots revealed a 100 % separation of all tested crop and weed species combinations. Spectra grouped in Poaceae and Chenopodiaceae clusters. Within the Poaceae cluster, C3 and C4 species differed significantly in heterogeneity. Thus, root spectra reflected the degree of kinship. To quantify species proportion in root mixtures, a two- and a three-species model for species quantification in root mixtures of maize, barnyard grass, and wild oat was calculated. The models showed low standard errors of prediction (RMSEP and high residual predictive deviation (RPD values in an external test set validation. Hence, FT MIR-ATR spectroscopy seems to be a promising tool for root research even between closely related plant species.

  3. Multivariate Analysis, Description, and Ecological Interpretation of Weed Vegetation in the Summer Crop Fields of Anhui Province, China

    Institute of Scientific and Technical Information of China (English)

    Sheng QIANG

    2005-01-01

    Province; Alopecurus aequalis Sobol. was the dominant weed in this group. Other main weeds in this group included Malachium aquaticum (L.) Fries, Stellaria alsine Grimm, Alopecurus japonicus Steud., and Lapsana apogonoides Maxim. Thus, the weed community distributions in this group were described as the Alopecurus weed vegetation type. The paddy soil group could be divided into two subgroups, one southern and one central paddy soil subgroup. A strategy for integrated weed management is suggested according to the weed distribution pattern. The present study serves as a good example of how a quantitative researchmethod was used to associate a visual estimate of weed infestation with multivariate analyses, such as PCA and CCA, and how this method can be applied to the study of weed vegetation on arable land.

  4. Experiment of 30%Glyphosate Oil Miscible Flowable Concentrate Against Weeds Control in Citrus Garden%30%草甘膦油悬浮剂防治柑橘园杂草药效试验

    Institute of Scientific and Technical Information of China (English)

    王平

    2013-01-01

    30%草甘膦油悬浮剂防治柑橘园杂草药效试验结果表明,30%草甘膦油悬浮剂相比较于50%草甘膦可溶性粉剂,对柑橘园杂草鼠麴草、繁缕、看麦娘等有很好的防治效果。%The experiment of 30% glyphosate oil miscible flowable concentrate agarinst weed control in citrus garden showed that ,30%glyphosate oil miscible flowable concentrate had good control effect compared to 50% glyphosate soluble powder on the weeds in citrus garden , including Herba Gnaphaii Affinis,Stellaria media(Linn.) Cyrill.,Alopecurus aequalis etc.

  5. Seasonal pattern of photosynthesis in individual grass leaves and other plant parts in Arctic Alaska with a portable 14CO2 system

    International Nuclear Information System (INIS)

    A portable system for photosynthesis determinations has been used under field conditions in the Arctic at Barrow, Alaska. Maximum photosynthetic rates were greater than 18 mg CO2.dm-2.h-1 in a number of species and were comparable with those of other C3 plants in arctic and temperate areas. Rates were closely coupled to irradiance. Plant components other than expanded blades were active in CO2 uptake. In Dupontia fischeri, leaf sheaths and culms possessed rates greater than 50 percent those of mature leaves. The leaves of D. fischeri and Alopecurus alpinus are produced sequentially and possess distinct seasonal patterns which appear related to leaf growth, maturation, and senescence stages. Thus, even in the short growing season of the Arctic, these grasses possess sequential patterns of leaf development and photosynthesis rather than a synchronized early season burst of leaf production. (U.S.)

  6. The benefits of being big: effects of body size on energy budgets of three wintering goose species grazing Carex beds in the Yangtze River Floodplain, China

    DEFF Research Database (Denmark)

    Wang, Xin; Zhang, Yong; Zhao, Meijuan;

    2013-01-01

    partitioning in the distribution of closely related species. By estimating daily energy expenditure (based on observed activity budgets) and energy intake (using the indigestible marker method in food and faeces), we compared the field energy budgets of three wintering herbivorous goose species differing in......Herbivores of different body size vary in food selection because of their different metabolic requirements and abilities to harvest and digest food. Compared with smaller grazers, larger ones require higher food quantity but can tolerate poorer quality. This divergence may also explain habitat...... which failed to do so and could only maintain positive energy budgets by grazing high-quality Alopecurus, Cynodon and Eleocharis. However, all three species failed to maintain positive energy balance and lost mass in midwinter. These results have important implications for explaining the divergent...

  7. 西藏嵩草属(莎草科)的修订%Revision of Kobresia (Cyperaceae) in Xizang (Tibet)

    Institute of Scientific and Technical Information of China (English)

    张树仁

    2004-01-01

    在标本观察和野外调查的基础上,对西藏的嵩草属Kobresia植物进行了分类学修订,共确认了36种和1亚种.更正了6个类群的学名,它们正确的名称是K. esenbeckii,K. fissiglumis,K. gammiei,K. littledalei,K. myosuroides ssp. bistaminata和K. vaginosa.有13个名称,即K. angusta,K. cercostachys var. capillacea,K. clarkeana,K. curticeps var. gyirongensis,K. deasyi,K. glaucifolia,K. hookeri,K. nudicarpa,K. prainii var. elliptica,K. seticulmis,K. stenocarpa,K. stenocarpa var. simplex和K. williamsii处理为异名,其中K. prainii var. elliptica,K. glaucifolia和K. stenocarpa var. simplex为新异名.发现了西藏分布的一个新记录种密穗嵩草K. handel-mazzettii.还收录了最近发表的假钩状嵩草K. pseuduncinoides和阔鳞嵩草K. woodii.此外,重新编制了西藏嵩草属分种和亚种检索表,并较为详细地登记了各类群在西藏的分布地点.

  8. Using transplants to measure accumulation rates of epiphytic bryophytes in forests of western Oregon

    Science.gov (United States)

    Rosso, A.L.; Muir, Patricia S.; Rambo, T.

    2001-01-01

    We sought a simple and effective transplant method that could be used to measure biomass accumulation rates of epiphytic bryophytes. Trials were carried out in the Pseudotsuga menziesii-dominated forests of western Oregon. We tested multiple transplant methods over a 13-month period while comparing accumulation rates of Antitrichia curtipendula (Hedw.) Brid. and Isothecium myosuroides Brid. among an old-growth stand, a young stand, and a recent clearcut. In our study area, Antitrichia is considered to be an old-growth associate while Isothecium is a more ubiquitous species. Methods tested included containment in net bags, containment in hairnets, and directly tying mats to substrates. Three sizes of transplants were tested with both natural and inert artificial substrates. Transplants of approximately five g enclosed in plastic net bags and tied to either natural or artificial substrates worked well for our purposes. Only minor differences were found in mean accumulation rates between the old growth and young stand, though variation in accumulation rates was higher in the old growth. Neither species appeared capable of surviving in the clearcut. Antitrichia accumulated biomass 60% faster in the canopy than in the understory on average. Antitrichia also accumulated at a faster rate than Isothecium, with mean 13-month biomass increases of 11.8 and 3.7% respectively for 5 g transplants in the understory. Our results suggest that Antitrichia's association with old growth may be due more to dispersal or establishment limitations than to a decreased ability to grow in young stands.

  9. Application Control Technology of Pinoxaden 50 g/L EC in Barley Field%50 g/L 唑啉草酯乳油防除大麦田杂草应用技术

    Institute of Scientific and Technical Information of China (English)

    李涛; 钱振官; 温广月; 李国梁; 石建福; 陈谊君; 沈国辉

    2014-01-01

    50 g/L唑啉草酯乳油可安全应用于大麦田,有效防除硬草、看麦娘等禾本科杂草。50 g/L唑啉草酯乳油80~120 mL/667 m2于杂草2~3分蘖期使用,药后90 d对硬草、看麦娘等禾本科杂草的防效仍高达95%以上,显著优于对照药剂50%异丙隆可湿性粉剂150 g/667 m2处理。%Pinoxaden 50 g/L EC applied at 80~120 mL/667 m2 ( equivalent to 60~90 g a.i./hm2 ) to grass weeds at the 2~3 tiller growth stage provided excellent control,especially of Sclerochloa kengiana and Alopecurus aequalis at 90 days after treatment with good selectivity to barley.The pinoxaden formulation was superior to isoproturon WP applied at 150 g/667 m2 .

  10. Metals and arsenic in soils and corresponding vegetation at Central Elbe river floodplains (Germany)

    Energy Technology Data Exchange (ETDEWEB)

    Overesch, M. [Department for Geo- and Agroecology, Institute of Spatial Analysis and Planning in Areas of Intensive Agriculture, University of Vechta, P.O. Box 1553, D-49364 Vechta (Germany)]. E-mail: moveresch@ispa.uni-vechta.de; Rinklebe, J. [Department of Soil Science, UFZ Center for Environmental Research Leipzig-Halle, Theodor-Lieser-Strasse 4, D-06120 Halle (Germany)]. E-mail: joerg.rinklebe@ufz.de; Broll, G. [Department for Geo- and Agroecology, Institute of Spatial Analysis and Planning in Areas of Intensive Agriculture, University of Vechta, P.O. Box 1553, D-49364 Vechta (Germany)]. E-mail: gbroll@ispa.uni-vechta.de; Neue, H.-U. [Department of Soil Science, UFZ Center for Environmental Research Leipzig-Halle, Theodor-Lieser-Strasse 4, D-06120 Halle (Germany)]. E-mail: heinz-ulrich.neue@ufz.de

    2007-02-15

    Floodplain soils at the Elbe river are frequently polluted with metals and arsenic. High contents of these pollutants were detected down to subsoil layers. NH{sub 4}NO{sub 3}-extractable (phytoavailable) Cd, Ni, and Zn were elevated in horizons with high acidity. Among five common floodplain plant species, Artemisia vulgaris showed highest concentrations of Cd, Cu, and Hg, Alopecurus pratensis of As and Phalaris arundinacea of Ni, Pb, and Zn. Relationships were weak between metal concentrations in plants and phytoavailable stocks in soil. As and Hg uptake seems to be enhanced on long submerged soils. Enrichments of Cd and Hg are linked to a special plant community composition. Grassland herbage sampled in July/August revealed higher concentrations of As (+122%), Hg (+124%), and Pb (+3723%) than in May. To limit harmful transfers into the food chain, low-lying terraces and flood channels revealing highest contaminations or phytoavailabilities should be excluded from mowing and grazing. - Soils in the Elbe river floodplains are highly polluted with metals and arsenic and a critical enrichment in the grassland herbage seems to be most likely in flood channels or within special plant species.

  11. Metals and arsenic in soils and corresponding vegetation at Central Elbe river floodplains (Germany)

    International Nuclear Information System (INIS)

    Floodplain soils at the Elbe river are frequently polluted with metals and arsenic. High contents of these pollutants were detected down to subsoil layers. NH4NO3-extractable (phytoavailable) Cd, Ni, and Zn were elevated in horizons with high acidity. Among five common floodplain plant species, Artemisia vulgaris showed highest concentrations of Cd, Cu, and Hg, Alopecurus pratensis of As and Phalaris arundinacea of Ni, Pb, and Zn. Relationships were weak between metal concentrations in plants and phytoavailable stocks in soil. As and Hg uptake seems to be enhanced on long submerged soils. Enrichments of Cd and Hg are linked to a special plant community composition. Grassland herbage sampled in July/August revealed higher concentrations of As (+122%), Hg (+124%), and Pb (+3723%) than in May. To limit harmful transfers into the food chain, low-lying terraces and flood channels revealing highest contaminations or phytoavailabilities should be excluded from mowing and grazing. - Soils in the Elbe river floodplains are highly polluted with metals and arsenic and a critical enrichment in the grassland herbage seems to be most likely in flood channels or within special plant species

  12. An experimental approach to assessing the effects of mining subsidence on a flood meadow community

    International Nuclear Information System (INIS)

    The Lower Derwent Valley (LDV) is a candidate Special Area of Conservation (SAC) under the provisions of the UK 1994 Conservation Regulations for its internationally important Alopecurus pratense-Sanguisorba officinalis flood meadow vegetation. Mining from RJB's Selby Complex (UK's largest mine) has taken place around and under the LDV since the 1980s. Under the provisions of the Regulations the potential effects of mining subsidence have been recently reviewed. From field data and models it has been predicted that the resulting small amount of subsidence is unlikely to have a deleterious effect on the composition and extent of the key community. While the proposed long-term monitoring will verify the prediction, it will be some years before the results will be available. In order to identify incipient changes in grassland community and to implement any necessary mitigation measures before significant changes occur, a field experiment was set up in late 1996 to assess the effects of increased wetness and inundation which might be induced by subsidence. This involved the transplantation of turves from the different grassland communities within and along a previously defined gradient of relative wetness and inundation. The response of the communities to the different conditions is being monitored. The background studies and the results of the transplantation so far will be presented

  13. Global perspective of herbicide-resistant weeds.

    Science.gov (United States)

    Heap, Ian

    2014-09-01

    Two hundred and twenty weed species have evolved resistance to one or more herbicides, and there are now 404 unique cases (species × site of action) of herbicide-resistant weeds globally. ALS inhibitor-resistant weeds account for about a third of all cases (133/404) and are particularly troublesome in rice and cereals. Although 71 weed species have been identified with triazine resistance, their importance has dwindled with the shift towards Roundup Ready® crops in the USA and the reduction of triazine usage in Europe. Forty-three grasses have evolved resistance to ACCase inhibitors, with the most serious cases being Avena spp., Lolium spp., Phalaris spp., Setaria spp. and Alopecurus myosuroides, infesting more than 25 million hectares of cereal production globally. Of the 24 weed species with glyphosate resistance, 16 have been found in Roundup Ready® cropping systems. Although Conyza canadensis is the most widespread glyphosate-resistant weed, Amaranthus palmeri and Amaranthus tuberculartus are the two most economically important glyphosate-resistant weeds because of the area they infest and the fact that these species have evolved resistance to numerous other herbicide sites of action, leaving growers with few herbicidal options for their control. The agricultural chemical industry has not brought any new herbicides with novel sites of action to market in over 30 years, making growers reliant on using existing herbicides in new ways. In addition, tougher registration and environmental regulations on herbicides have resulted in a loss of some herbicides, particularly in Europe. The lack of novel herbicide chemistries being brought to market combined with the rapid increase in multiple resistance in weeds threatens crop production worldwide. PMID:24302673

  14. Computational simulations of structural role of the active-site W374C mutation of acetyl-coenzyme-A carboxylase: multi-drug resistance mechanism.

    Science.gov (United States)

    Zhu, Xiao-Lei; Yang, Wen-Chao; Yu, Ning-Xi; Yang, Sheng-Gang; Yang, Guang-Fu

    2011-03-01

    Herbicides targeting grass plastidic acetyl-CoA carboxylase (ACCase, EC 6.4.1.2) are selectively effective against graminicides. The intensive worldwide use of this herbicide family has selected for resistance genes in a number of grass weed species. Recently, the active-site W374C mutation was found to confer multi-drug resistance toward haloxyfop (HF), fenoxaprop (FR), Diclofop (DF), and clodinafop (CF) in A. myosuroides. In order to uncover the resistance mechanism due to W374C mutation, the binding of above-mentioned four herbicides to both wild-type and the mutant-type ACCase was investigated in the current work by molecular docking and molecular dynamics (MD) simulations. The binding free energies were calculated by molecular mechanics-Poisson-Boltzmann surface area (MM/PBSA) method. The calculated binding free energy values for four herbicides were qualitatively consistent with the experimental order of IC(50) values. All the computational model and energetic results indicated that the W374C mutation has great effects on the conformational change of the binding pocket and the ligand-protein interactions. The most significant conformational change was found to be associated with the aromatic amino acid residues, such as Phe377, Tyr161' and Trp346. As a result, the π-π interaction between the ligand and the residue of Phe377 and Tyr161', which make important contributions to the binding affinity, was decreased after mutation and the binding affinity for the inhibitors to the mutant-type ACCase was less than that to the wild-type enzyme, which accounts for the molecular basis of herbicidal resistance. The structural role and mechanistic insights obtained from computational simulations will provide a new starting point for the rational design of novel inhibitors to overcome drug resistance associated with W374C mutation. PMID:20499260

  15. Plant selection for dewatering and reclamation of tailings

    International Nuclear Information System (INIS)

    A two-phase greenhouse experiment was conducted to identify the most suitable species for dewatering and reclamation of Composite Tailings (CT) from Alberta oil sands operated by Syncrude Canada Ltd. and Copper Mine Tailings (CMT) from the Kennecott site in Utah. A total of 15 and 9 plant species were selected for testing in CT and CMT, respectively. In Phase 1, distilled water was added weekly to simulate local precipitation. The initial solids content were 80% and 76% and the electrical conductivities were 1.1 dS/m and 3.2 dS/m for CT and CMT, respectively. All plants survived after a ten-week period. In Phase 2 only process water was added weekly to provide a worst case scenario of no precipitation and water recharge due only to process water being released from within the tailings. The initial solids contents were 65% and 76% for CT and CMT, respectively. Surface (0--3 in.) salinity increased dramatically due to the application of process water only; at the end of Phase 2 it had reached toxic levels of approximately 18.9 dS/m and 35.0 dS/m in CT and CMT, respectively. Many plants showed signs of stress due to the high salinity level. The plants which performed the best under both phases in Composite Tailings were creeping foxtail (Alopecurus arundinaceus), reed canarygrass (Phalaris arundinacea), Altai wildrye (Elymus angustus), and red top (Agrostis stolonifera); and in Copper Mine Tailings were Altai wildrye, smooth bromegrass (Bromus inermis) and creeping foxtail

  16. Diversity and distribution of 16S rRNA and phenol monooxygenase genes in the rhizosphere and endophytic bacteria isolated from PAH-contaminated sites

    Science.gov (United States)

    Peng, Anping; Liu, Juan; Ling, Wanting; Chen, Zeyou; Gao, Yanzheng

    2015-07-01

    This is the first investigation of the diversity and distribution of 16S rRNA and phenol monooxygenase (PHE) genes in endophytic and rhizosphere bacteria of plants at sites contaminated with different levels of PAHs. Ten PAHs at concentrations from 34.22 to 55.29 and 45.79 to 97.81 mg·kg-1 were measured in rhizosphere soils of Alopecurus aequalis Sobol and Oxalis corniculata L., respectively. The diversity of 16S rRNA and PHE genes in rhizosphere soils or plants changed with varying PAH pollution levels, as shown based on PCR-DGGE data. Generally, higher Shannon-Weiner indexes were found in mild or moderate contaminated areas. A total of 82 different bacterial 16S rRNA gene sequences belonging to five phyla; namely, Acfinobacteria, Proteobacteria, Chloroflexi, Cyanophyta, and Bacteroidetes, were obtained from rhizosphere soils. For the 57 identified PHE gene sequences, 18 were excised from rhizosphere bacteria and 39 from endophytic bacteria. The copy numbers of 16S rRNA and PHE genes in rhizosphere and endophytic bacteria varied from 3.83 × 103 to 2.28 × 106 and 4.17 × 102 to 1.99 × 105, respectively. The copy numbers of PHE genes in rhizosphere bacteria were significantly higher than in endophytic bacteria. Results increase our understanding of the diversity of rhizosphere and endophytic bacteria from plants grown in PAH-contaminated sites.

  17. Evaluation of selected wild plants flowering season 1991 - 2009 (1991 - 2000 & 2001 - 2009)

    Science.gov (United States)

    Hajkova, L.; Nekovar, J.; Novak, M.; Richterova, D.

    2009-09-01

    The subsequent wild plants are observed by volunteer observers at CHMI phenological network: CALTHA palustris L., ANEMONE nemorosa L., HEPATICA nobilis Mill., RANUNCULUS acer L., FRAGARIA vesca L., TRIFOLIUM repens L., HYPERICUM perforatum L., CHAMAENERION angustifolium L. Holub, VACCINIUM myrtillus L., LAMIUM album L., CHRYSANTHEMUM leucanthemum L., TUSSILAGO farfara L., PETASITES albus (L.) Gaert., PETASITES hybridus (L.) G. M. Sch., CONVALLARIA majalis L., GALANTHUS nivalis L., DACTYLIS glomerata L., ALOPECURUS pratensis L. and others. Some of them start to blossom in early spring, some others in the summer. Part of them belong to very important allergens, part of them have medicinal effects. Phenophases first leaves (FL - BBCH11), inflorescence emergence (IE - BBCH 51), beginning and end of flowering (BF - BBCH 61, EF - BBCH 69) are observed by these species. Statistical parameters (average, median, lower quartile, upper quartile, minimum, maximum, standard deviation, variation range and variation coefficient) of phenophase onset are computed from all of phenological stations in Czechia for the period 1991 - 2009. The phenophase onset and phenophase duration depend not only on genetic base but also on external effects such as weather. We have compiled dynamics of temperature to phenophase onset according CHMI meteorological stations for the same period 1991 - 2009 (especially sums of active temperatures above biological minimum 5°C and progression of extreme temperatures). We have also compared results between two periods (1991 - 2000, 2001 - 2009). Phenological stations are at different altitude. At this case study were used results from 4 phenological stations at altitude ( 500 m asl). GALANTHUS nivalis L. Station: Lednice (165 m n. m.) Period: 1991 - 2000 Statistical parameter/phenophase BBCH 61 BBCH 69 Average 62 94 Median 60 97 Lower quartile 57 86 Upper quartile 66 101 Minimum 51 70 Maximum 79 116 Variation range 28 46 Standard deviation 8,6 12

  18. Analysis of landslide overgrowing rates at Vaskiny Dachi key site, Central Yamal, Russia

    Science.gov (United States)

    Khomutov, A.

    2009-04-01

    An estimation of overgrowing of landslide-affected slopes by vegetation at three main landslide elements: shear surface, landslide body and "frontal zone" at Vaskiny Dachi key site is presented. Vaskiny Dachi key site is located in the watershed of Se-Yakha and Mordy-Yakha rivers on Central Yamal, Russia. The area is represented by highly-dissected alluvial-lacustrine-marine plains and terraces. The closest to Vaskiny Dachi climate station is Marresale, about 90 km southwest of Vaskiny Dachi, at the Kara sea coast. The weather here is probably somewhat cooler than at Vaskiny Dachi. The average annual (summer) air temperature at Marresale is -8.3° C (4.3° C) ("Russia's Weather" Server). To estimate vegetation cover dynamics on cryogenic landslides at "Vaskiny Dachi", data published by O.Rebristaya and others (1995) were used. Their observations were done in 1991-1993, and were supplemented by further field observations (Leibman et al., 2000, Khomutov & Leibman 2007) and by field and remote sensing observations in 2008. An estimation of vegetation cover dynamics on cryogenic landslides at "Vaskiny Dachi" leads to the following results. Immediately after landsliding in 1989, landslide shear surface was bare without any vegetation, landslide body had initial vegetation, and "frontal zone" was under liquefied sediment masses. "Frontal zone" formed in front of a landslide body, appears as a result of damming of drainage routes by a landslide body with flooding of the shear surface "upstream" of the landslide body, formation of a sedge-cottongrass meadow there, and swamping downstream (Khomutov & Leibman 2007). By 1993, landslide shear surface got overgrown by species subordinate in surrounding initial landscapes (Alopecurus alpinus, Festuca ovina, Calamagrostis neglecta, Poa alpigena ssp. Alpigena, etc.). Landslide body was covered by initial communities which got depressed: vitality of Salix polaris, Vaccinium vitis-idaea was reduced, dead off moss cover and overgrown

  19. 长期施肥对红壤双季稻冬闲田春季杂草群落的影响%Effects of long-term fertilization on spring season weed community in winter fallow paddy field in red soil area under double-rice cropping system

    Institute of Scientific and Technical Information of China (English)

    董春华; 曾希柏; 石林; 高菊生

    2015-01-01

    -term fertilization experiment included five fertilization treatments of application of organic fertilizer, chemical fertilizer and combined application of organic and inorganic fertilizers with the same rates of nitrogen (N), phosphorus (P) and potassium (K) in both the organic and chemical fertilizers, which were no fertilizer (CK), organic fertilizer (composted cattle manure, M), combined application of P and K inorganic fertilizer and organic fertilizer (PKM), application of inorganic N, P, and K fertilizer (NPK), combined application of N, K inorganic fertilizer and organic fertilizer (NKM), combined application of N, P inorganic fertilizer and organic fertilizer (NPM), and combined application of N, P, K inorganic fertilizer and organic fertilizer (NPKM). The results showed that the dominant weed species changed and the total density and total biomass of weed communities increased under combined application of organic and inorganic fertilizers. NKM treatment had the largest number of weed species, while the least weed species number was under NPM treatment. Species diversity index (1.118 6), evenness index (0.732 3) and dominance index (0.629 7) of weed communities under M treatment were larger than those under the other treatments. However, M treatment had the lowest total weed density (297.0 plant×0.25m-2). Also NPK treatment had the lowest total weed biomass (58.0 g×0.25m-2). Compared with other treatments, NPM treatment significantly decreased diversity, evenness and dominance indexes of weed communities, and had the highest total weed density (539.7 plant×0.25m-2) and total weed biomass (109.5 g×0.25m-2), respectively. Alopecurus japonicas was the dominant weed species, and had weed density of 428.0 plant×0.25m-2 and relative weed density of 79.31%under NPM treatment, which were significantly higher than those of dominant weeds under other treatments. It was noted in this study that total dry biomass of weeds was positively correlated with content of soil alkali