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Glyphosate-resistant horseweed made sensitive to glyphosate: low-temperature suppression of glyphosate vacuolar sequestration revealed by 31P NMR.  

UK PubMed Central (United Kingdom)

BACKGROUND: Horseweed has been the most invasive glyphosate-resistant (GR) weed, spreading to 16 states in the United States and found on five continents. The authors have previously reported that GR horseweed employs rapid vacuolar sequestration of glyphosate, presumably via a tonoplast transporter, substantively to reduce cytosolic glyphosate concentrations.1 It was hypothesized that glyphosate sequestration was the herbicide resistance mechanism. If resistance is indeed endowed by glyphosate sequestration, suppression of sequestration offers the potential for controlling GR horseweed at normal herbicide field-use rates. RESULTS: Low-temperature (31) P NMR experiments performed in vivo with GR cold-acclimated horseweed showed markedly suppressed vacuolar accumulation of glyphosate even 3 days after glyphosate treatment. [In stark contrast, 85% of the visible glyphosate was sequestered 24 h after spraying warm-acclimated GR horseweed.] Cold-acclimated GR horseweed treated at normal use rates and maintained at low temperature succumbed to the lethal effects of glyphosate over a 40 day period. Treatment of GR horseweed in the field when temperatures were cooler showed the predicted positive herbicidal response. CONCLUSIONS: Low temperature markedly diminishes vacuolar sequestration of glyphosate in the GR horseweed biotype, yielding a herbicide response equivalent to that of the sensitive biotype. This supports the recent hypothesis1 that glyphosate sequestration is the resistance mechanism employed by GR horseweed.

Ge X; d'Avignon DA; Ackerman JJ; Duncan B; Spaur MB; Sammons RD

2011-10-01

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Glyphosate effects on gas exchange and chlorophyll fluorescence responses of two Lolium perenne L. biotypes with differential herbicide sensitivity.  

UK PubMed Central (United Kingdom)

Despite the extensive use of glyphosate, how it alters the physiology and metabolism of plants is still unclear. Photosynthesis is not regarded to be a primary inhibitory target of glyphosate, but it has been reported to be affected by this herbicide. The aim of the current research was to determine the effects of glyphosate on the light and dark reactions of photosynthesis by comparing glyphosate-susceptible and glyphosate-resistant Lolium perenne biotypes. After glyphosate treatment, accumulation of reduced carbohydrates occurred before a decrease in gas exchange. Stomatal conductance and CO(2) assimilation were reduced earlier than chlorophyll fluorescence and the amount of chlorophyll in susceptible plants. In the glyphosate-resistant biotype, stomatal conductance was the only parameter slightly affected only 5 days post-application. In susceptible plants, the initial glyphosate effects on gas exchange could be a response to a feedback regulation of photosynthesis. Since the herbicide affects actively growing tissues regardless of the inhibition of photosynthesis, the demand of assimilates decreased and consequently induced an accumulation of carbohydrates in leaves. We concluded that stomatal conductance could be a very sensitive parameter to assess both the susceptibility/resistance to glyphosate before the phytotoxic symptoms become evident.

Yanniccari M; Tambussi E; Istilart C; Castro AM

2012-08-01

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Glyphosate resistance in Sorghum halepense and Lolium rigidum is reduced at suboptimal growing temperatures.  

UK PubMed Central (United Kingdom)

BACKGROUND: Glyphosate resistance in populations of the C(4) perennial Sorghum halepense (Johnsongrass) and C(3) annual Lolium rigidum (rigid ryegrass) has evolved and been documented in many cropping areas around the globe. In S. halepense and in the majority of reported cases in L. rigidum the glyphosate resistance trait has been associated with a mechanism that reduces glyphosate translocation within plants. Here, the significant decrease in the glyphosate resistance level when resistant plants of S. halepense and L. rigidum are grown at suboptimal cool temperature conditions is reported. RESULTS: Lowering temperature from 30 to 19 °C in S. halepense and from 19 to 8 °C in L. rigidum significantly reduced both plant survival and above-ground biomass produced by glyphosate-resistant plants. Thus, glyphosate resistance parameters significantly decreased when glyphosate-treated resistant plants of both species were grown under non-optimal temperature conditions. The results suggest that the resistance mechanism against glyphosate damage is less efficient at sub-optimal [corrected] growing temperatures. CONCLUSION: It is possible to increase the control of glyphosate-resistant S. halepense and L. rigidum populations by treatment with glyphosate during growing conditions at suboptimal low temperatures. Conversely, glyphosate failure will continue to occur on glyphosate-resistant populations treated during periods of higher temperatures

Vila-Aiub MM; Gundel PE; Yu Q; Powles SB

2013-02-01

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Glyphosate reduces urediniospore development and Puccinia psidii disease severity on Eucalyptus grandis.  

UK PubMed Central (United Kingdom)

BACKGROUND: Recent studies have shown the effects of glyphosate drift on decreasing rust intensity on Eucalyptus grandis plants. However, the effects of the herbicide on Puccinia psidii initial development are unknown. In this study the systemic action of glyphosate on rust severity was evaluated on Eucalyptus plants maintained under greenhouse conditions. Urediniospore germination and apressorium formation on detached leaves and on water agar medium, previously treated with glyphosate, were also evaluated. RESULTS: Rust severity and the number of urediniospores per leaf area were significantly reduced with increasing glyphosate doses, even on branches not directly treated with the herbicide, indicating a systemic effect of glyphosate on pathogen development. Similarly, higher glyphosate doses also reduced germination and apressorium formation on detached Eucalyptus leaves, regardless of the direct application of the product on the leaf limb or on the petiole base. Puccinia psidii urediniospore germination in water agar medium also decreased with increasing herbicide doses. CONCLUSIONS: Reductions in germination and apressorium formation of P. psidii urediniospores with increasing glyphosate dose indicate that a lower severity and intensity of the disease may perhaps be due to blockage of the shikimic acid pathway in the fungal metabolic system.

Santos LD; Graça RN; Alfenas AC; Ferreira FA; Melo CA; Machado MS

2011-07-01

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Anatomia foliar de Lolium multiflorum sensível e resistente ao glyphosate/ Leaf anatomy of Lolium multiflorum sensitive and resistant to glyphosate  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Este trabalho foi desenvolvido com o intuito de contribuir para o conhecimento anatômico da espécie Lolium multiflorum e, a partir disso, observar possíveis alterações que possam elucidar o mecanismo que confere resistência ao herbicida glyphosate. Para isso, realizou-se um experimento com quatro biótipos dessa espécie com distinta sensibilidade ao herbicida glyphosate, sendo um sensível (B1S) e três resistentes (B2R, B3R e B4R). As análises ocorreram a partir (more) de secções transversais e longitudinais dos órgãos vegetativos de plantas no estádio de afilhamento. Anatomicamente, o azevém caracteriza-se por apresentar grande quantidade de estômatos e de células buliformes, bem como mesofilo homogêneo constituído apenas de células paliçádicas compactamente distribuídas. Comparativamente, não ocorrem diferenças morfológicas evidentes que possam ser usadas para diferir biótipos sensíveis de resistentes, no entanto, nota-se que biótipos resistentes, especialmente B3R e B4R, apresentaram maior densidade estomática em relação aos demais. Ainda, os biótipos resistentes apresentaram maior quantidade de espaços intercelulares no mesofilo e feixes vasculares com menor quantidade de floema em relação ao xilema, o que, por suas funções na planta, pode colaborar para a menor sensibilidade ao herbicida. Abstract in english This work aimed to contribute to the anatomical knowledge of the species Lolium multiflorum and to observe possible changes that may elucidate the mechanism that confers its resistance to the herbicide glyphosate. Thus, an experiment was conducted using four biotypes of this species with distinct sensitivities to the herbicide glyphosate: one susceptible (B1S) and three resistant biotypes (B2R, B3R and B4R). Analyses were conducted on the transverse and longitudinal secti (more) ons of the vegetative organs of the plants at the tillering stage. Anatomically, ryegrass is characterized as having a large number of stomata and buliform cells as well as homogeneous mesophylls constituted only of palisade cells compactly distributed. Comparatively, no evident morphological differences occur that can be used to distinguish sensitive from resistant biotypes; however, the resistant biotypes, especially B3R B4R, presented higher stomatal density, compared to the others. Still, the resistant biotypes had a higher amount of intercellular spaces in the mesophyll and vascular bundles with a smaller amount of phloem compared to the xylem, which, because of their functions in the plants, may contribute to the lower sensitivity to the herbicide.

Galvani, J.; Rizzardi, M.A.; Carneiro, C.M.; Bianchi, M.A

2012-06-01

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Anatomia foliar de Lolium multiflorum sensível e resistente ao glyphosate Leaf anatomy of Lolium multiflorum sensitive and resistant to glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available Este trabalho foi desenvolvido com o intuito de contribuir para o conhecimento anatômico da espécie Lolium multiflorum e, a partir disso, observar possíveis alterações que possam elucidar o mecanismo que confere resistência ao herbicida glyphosate. Para isso, realizou-se um experimento com quatro biótipos dessa espécie com distinta sensibilidade ao herbicida glyphosate, sendo um sensível (B1S) e três resistentes (B2R, B3R e B4R). As análises ocorreram a partir de secções transversais e longitudinais dos órgãos vegetativos de plantas no estádio de afilhamento. Anatomicamente, o azevém caracteriza-se por apresentar grande quantidade de estômatos e de células buliformes, bem como mesofilo homogêneo constituído apenas de células paliçádicas compactamente distribuídas. Comparativamente, não ocorrem diferenças morfológicas evidentes que possam ser usadas para diferir biótipos sensíveis de resistentes, no entanto, nota-se que biótipos resistentes, especialmente B3R e B4R, apresentaram maior densidade estomática em relação aos demais. Ainda, os biótipos resistentes apresentaram maior quantidade de espaços intercelulares no mesofilo e feixes vasculares com menor quantidade de floema em relação ao xilema, o que, por suas funções na planta, pode colaborar para a menor sensibilidade ao herbicida.This work aimed to contribute to the anatomical knowledge of the species Lolium multiflorum and to observe possible changes that may elucidate the mechanism that confers its resistance to the herbicide glyphosate. Thus, an experiment was conducted using four biotypes of this species with distinct sensitivities to the herbicide glyphosate: one susceptible (B1S) and three resistant biotypes (B2R, B3R and B4R). Analyses were conducted on the transverse and longitudinal sections of the vegetative organs of the plants at the tillering stage. Anatomically, ryegrass is characterized as having a large number of stomata and buliform cells as well as homogeneous mesophylls constituted only of palisade cells compactly distributed. Comparatively, no evident morphological differences occur that can be used to distinguish sensitive from resistant biotypes; however, the resistant biotypes, especially B3R B4R, presented higher stomatal density, compared to the others. Still, the resistant biotypes had a higher amount of intercellular spaces in the mesophyll and vascular bundles with a smaller amount of phloem compared to the xylem, which, because of their functions in the plants, may contribute to the lower sensitivity to the herbicide.

J. Galvani; M.A. Rizzardi; C.M. Carneiro; M.A Bianchi

2012-01-01

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Sensitivity of Ambrosia artemisiifolia to glufosinate and glyphosate at various developmental stages  

UK PubMed Central (United Kingdom)

Glufosinate and glyphosate at 375 g a.i. ha?¹ and 540 g a.e. ha?¹, respectively, were assessed for control of Ambrosia artemisiifolia under non-crop conditions at four different developmental stages (vegetative, BBCH 14; bud appearance, BBCH 53-55; onset of pollen production, BBCH 61; mid female flowering, BBCH 73-77). Both herbicides displayed high efficacies at all development stages. However, after treatments at BBCH 14, new emergence or re-growth of A. artemisiifolia led to the presence of plants that produced pollen and seeds. Treatments at BBCH 53-55 gave more than 99.9% reduced pollen production. Seed production was more than 99.9% reduced by glyphosate and 92.0-99.8% by glufosinate. Treatments at BBCH 61 suppressed viable seed production by more than 99.8%. When treatments were made at BBCH 73-77, seed production by A. artemisiifolia was not significantly affected, but seed viability was decreased by 10-85%. Although significantly reduced, the number of viable seeds was still 283-652 and 827-3893 m?² in the plots treated by glufosinate and glyphosate respectively. It is concluded that on non-crop areas, herbicide treatment of A. artemisiifolia at bud appearance (BBCH 53-55) with glufosinate or glyphosate gave the most effective control of both pollen and seed production.

GAUVRIT C; CHAUVEL B

2010-10-01

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Glyphosate reduces spore viability and root colonization of arbuscular mycorrhizal fungi  

UK PubMed Central (United Kingdom)

Glyphosate is the most widely used herbicide in the world, but its effects on non-target organisms, such as arbuscular mycorrhizal fungi (AMF), are unclear. No studies have been found that made reference to effects of glyphosate on AMF spore viability despite its importance as a source of propagules for the perpetuation and spread of AMF in the system. The objective of this study was to evaluate the effect of glyphosate application on AMF spore viability, and their ability to colonize roots. Soil samples were collected from a grassland area located in the Flooding Pampa region (Argentina). We evaluated three herbicide rates: 0, 0.26 and 1× recommended field rate, 10 and 30 days after application. Part of the soil from each tray was used to estimate the spore viability, and the remainder was used as substrate for growing Lolium multiflorum Lam. One month after sowing, total root colonization and percentage of arbuscules and vesicles were determined. The spore viability in herbicide untreated soils was between 5.8- and 7.7-fold higher than in treated soils. This reduction was detected even when the lower rate was applied. Root colonization was significantly lower in plants grown in glyphosate treated soil than in untreated ones. A decrease in arbuscular colonization (but not in vesicles) was found in plants grown in soils treated with the highest herbicide rate. That would indicate that symbiosis functionality was affected, given that arbuscules are the main site for host–fungus nutrient exchange. The results indicate that soil residence time of glyphosate and/or its degradation products was enough to reduce AMF spore viability and their ability to colonize roots. This decrease in propagules viability may affect plant diversity, taking into account the different degrees of mycorrhizal dependency between plant species that may coexist in grassland communities.

Druille M; Cabello MN; Omacini M; Golluscio RA

2013-02-01

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Qualidade de sementes de algodão provenientes de plantas tratadas com doses reduzidas de glyphosate Quality of cotton seeds from plants submitted to reduced rates of glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available O presente trabalho teve como objetivo avaliar a influência do tratamento de plantas de algodoeiro com doses reduzidas de glyphosate, simulando deriva, na qualidade das sementes produzidas. Plantas dos cultivares ITA-90 e BRS-Facual foram tratadas em dois diferentes estádios de desenvolvimento (quatro e dez folhas) com as doses de 0, 180 e 360 g ha-1 de glyphosate. Avaliaram-se o rendimento de algodão em caroço, a qualidade das sementes, através de massa de 100 sementes, a porcentagem de emergência e a massa seca de plântulas emersas. Houve redução no rendimento de algodão em caroço em todos os tratamentos, exceto em plantas mais velhas tratadas com 180 g ha-1, sem afetar a qualidade das sementes.This work aimed to evaluate the influence of cotton plant treatment using reduced rates of glyphosate, simulating drift, on the quality of the seeds produced. The plants of the ITA-90 and BRS-Facual cultivars were treated at two different development stages (4 and 10 leaves) with glyphosate in the doses of 0; 180 and 360 g ha-1 ea. Cotton crop yield was evaluated. The material was seeded and seed quality evaluated, through mass of 100 seeds, emergence percentage and mass of plantules. There was a reduction in cotton production in the treatments, except in older plants treated with 180 g ha-1. No significant difference in plantule emergence was found in the different treatments.

O.M. Yamashita; S.C. Guimarães

2006-01-01

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TREATABILITY STUDIES OF PESTICIDE MANUFACTURING WASTEWATERS: GLYPHOSATE  

Science.gov (United States)

The report gives results of subjecting various combinations of glyphosate production wastestreams to biological treatment following lime-pretreatment to reduce high levels of glyphosate. Bench-scale biological treatment demonstrated that glyphosate did not appear to interfere wit...

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Aspectos morfofisiológicos de biótipos de azevém (Lolium multiflorum) sensíveis e resistentes ao glyphosate/ Morphophysiological aspects of ryegrass biotypes (Lolium multiflorum) sensitive and resistant to glyphosate  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O azevém é uma gramínea com elevado potencial de infestação em lavouras e pomares, e seu controle com glyphosate tem sido limitado devido à existência de biótipos resistentes a esse herbicida. Objetivou-se comparar quatro biótipos de azevém coletados em diferentes regiões do Rio Grande do Sul, com o intuito de testar a hipótese de que aspectos morfofisiológicos e fenológicos estejam vinculados à resistência. O experimento foi conduzido em casa de vegetaç? (more) ?o, onde um biótipo suscetível (B1S, Passo Fundo) e três resistentes ao glyphosate (B2R, Santa Maria; B3R, Júlio de Castilhos; e B4R, Vacaria) foram colhidos aos 126, 147, 168 e 189 dias de idade. O biótipo B1S mostrou 21 dias de antecipação no florescimento em relação aos demais biótipos. O biótipo B4R produziu significativamente mais folhas (43 por planta), afilhos (14 por planta), espigas (14 por planta), sementes (3.484 por planta) e matéria seca total (raízes + parte aérea = 13,8 g por planta). Conclui-se que biótipos sensíveis não podem ser diferidos de biótipos resistentes apenas por aspectos morfológicos relacionados ao vigor. Abstract in english Ryegrass has a high potential for infestation in crops and orchads and its control with glyphosate has been limited due to the existence of herbicide-resistant biotypes. The objective of this work was to compare four ryegrass biotypes collected from different regions in the state of Rio Grande do Sul, Brazil, to test the hypothesis that morphophysiological aspects and phenology are linked to resistance. The experiment was conducted in a greenhouse, where four biotypes, on (more) e susceptible (B1S, Passo Fundo) and three resistant to glyphosate (B2R, Santa Maria; B3R, Julio de Castillos; B4R, Vacaria) were collected at 126, 147, 168 and 189 days of age. Biotype B1S showed 21 days in advance of flowering in relation to the other biotypes. Biotype B4R produced significantly more leaves (43 per plant), tillers (14 per plant), ears (14 per plant), seeds (3484 per plant) and total dry matter (roots + shoot = 13.8 g per plant). It is concluded that sensitive biotypes cannot be distinguished from the resistant ones only by morphological aspects related to vigor.

Galvan, J; Rizzardi, M.A; Scheffer-Basso, S

2011-01-01

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Aspectos morfofisiológicos de biótipos de azevém (Lolium multiflorum) sensíveis e resistentes ao glyphosate Morphophysiological aspects of ryegrass biotypes (Lolium multiflorum) sensitive and resistant to glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available O azevém é uma gramínea com elevado potencial de infestação em lavouras e pomares, e seu controle com glyphosate tem sido limitado devido à existência de biótipos resistentes a esse herbicida. Objetivou-se comparar quatro biótipos de azevém coletados em diferentes regiões do Rio Grande do Sul, com o intuito de testar a hipótese de que aspectos morfofisiológicos e fenológicos estejam vinculados à resistência. O experimento foi conduzido em casa de vegetação, onde um biótipo suscetível (B1S, Passo Fundo) e três resistentes ao glyphosate (B2R, Santa Maria; B3R, Júlio de Castilhos; e B4R, Vacaria) foram colhidos aos 126, 147, 168 e 189 dias de idade. O biótipo B1S mostrou 21 dias de antecipação no florescimento em relação aos demais biótipos. O biótipo B4R produziu significativamente mais folhas (43 por planta), afilhos (14 por planta), espigas (14 por planta), sementes (3.484 por planta) e matéria seca total (raízes + parte aérea = 13,8 g por planta). Conclui-se que biótipos sensíveis não podem ser diferidos de biótipos resistentes apenas por aspectos morfológicos relacionados ao vigor.Ryegrass has a high potential for infestation in crops and orchads and its control with glyphosate has been limited due to the existence of herbicide-resistant biotypes. The objective of this work was to compare four ryegrass biotypes collected from different regions in the state of Rio Grande do Sul, Brazil, to test the hypothesis that morphophysiological aspects and phenology are linked to resistance. The experiment was conducted in a greenhouse, where four biotypes, one susceptible (B1S, Passo Fundo) and three resistant to glyphosate (B2R, Santa Maria; B3R, Julio de Castillos; B4R, Vacaria) were collected at 126, 147, 168 and 189 days of age. Biotype B1S showed 21 days in advance of flowering in relation to the other biotypes. Biotype B4R produced significantly more leaves (43 per plant), tillers (14 per plant), ears (14 per plant), seeds (3484 per plant) and total dry matter (roots + shoot = 13.8 g per plant). It is concluded that sensitive biotypes cannot be distinguished from the resistant ones only by morphological aspects related to vigor.

J Galvan; M.A Rizzardi; S Scheffer-Basso

2011-01-01

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Glyphosate-resistant goosegrass. Identification of a mutation in the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase.  

Science.gov (United States)

The spontaneous occurrence of resistance to the herbicide glyphosate in weed species has been an extremely infrequent event, despite over 20 years of extensive use. Recently, a glyphosate-resistant biotype of goosegrass (Eleusine indica) was identified in Malaysia exhibiting an LD(50) value approximately 2- to 4-fold greater than the sensitive biotype collected from the same region. A comparison of the inhibition of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity by glyphosate in extracts prepared from the resistant (R) and sensitive (S) biotypes revealed an approximately 5-fold higher IC(50)(glyphosate) for the (R) biotype. Sequence comparisons of the predicted EPSPS mature protein coding regions from both biotypes revealed four single-nucleotide differences, two of which result in amino acid changes. One of these changes, a proline to serine substitution at position 106 in the (R) biotype, corresponds to a substitution previously identified in a glyphosate-insensitive EPSPS enzyme from Salmonella typhimurium. Kinetic data generated for the recombinant enzymes suggests that the second substitution identified in the (R) EPSPS does not contribute significantly to its reduced glyphosate sensitivity. Escherichia coli aroA- (EPSPS deficient) strains expressing the mature EPSPS enzyme from the (R) biotype exhibited an approximately 3-fold increase in glyphosate tolerance relative to strains expressing the mature EPSPS from the (S) biotype. These results provide the first evidence for an altered EPSPS enzyme as an underlying component of evolved glyphosate resistance in any plant species. PMID:12114580

Baerson, Scott R; Rodriguez, Damian J; Tran, Minhtien; Feng, Yongmei; Biest, Nancy A; Dill, Gerald M

2002-07-01

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Glyphosate-resistant goosegrass. Identification of a mutation in the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase.  

UK PubMed Central (United Kingdom)

The spontaneous occurrence of resistance to the herbicide glyphosate in weed species has been an extremely infrequent event, despite over 20 years of extensive use. Recently, a glyphosate-resistant biotype of goosegrass (Eleusine indica) was identified in Malaysia exhibiting an LD(50) value approximately 2- to 4-fold greater than the sensitive biotype collected from the same region. A comparison of the inhibition of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity by glyphosate in extracts prepared from the resistant (R) and sensitive (S) biotypes revealed an approximately 5-fold higher IC(50)(glyphosate) for the (R) biotype. Sequence comparisons of the predicted EPSPS mature protein coding regions from both biotypes revealed four single-nucleotide differences, two of which result in amino acid changes. One of these changes, a proline to serine substitution at position 106 in the (R) biotype, corresponds to a substitution previously identified in a glyphosate-insensitive EPSPS enzyme from Salmonella typhimurium. Kinetic data generated for the recombinant enzymes suggests that the second substitution identified in the (R) EPSPS does not contribute significantly to its reduced glyphosate sensitivity. Escherichia coli aroA- (EPSPS deficient) strains expressing the mature EPSPS enzyme from the (R) biotype exhibited an approximately 3-fold increase in glyphosate tolerance relative to strains expressing the mature EPSPS from the (S) biotype. These results provide the first evidence for an altered EPSPS enzyme as an underlying component of evolved glyphosate resistance in any plant species.

Baerson SR; Rodriguez DJ; Tran M; Feng Y; Biest NA; Dill GM

2002-07-01

15

Glyphosate effects on photosynthesis, nutrient accumulation, and nodulation in glyphosate-resistant soybean.  

Science.gov (United States)

Previous studies demonstrated that the photosynthesis of some cultivars of first (GR1) and second generation (GR2) glyphosate-resistant soybean was reduced by glyphosate. The reduction in photosynthesis caused by glyphosate might affect nutrient uptake and lead to lower plant biomass production and ...

16

Bases for interactions between saflufenacil and glyphosate in plants.  

UK PubMed Central (United Kingdom)

Buckwheat (Fagropyrum esculentum Moench.), cabbage (Brassica oleracea L), and conventional and glyphosate-resistant varieties of canola (Brassica napus L.) were used to study the bases of saflufenacil and glyphosate interactions. Compared to the addition of Merge (surfactant), the addition of both Transorb (i.e., commercial product, Transorb formulation with glyphosate) and Merge increased the cuticular absorption of [(14)C] saflufenacil in cabbage plants with thick epicuticular wax layers. However, in all cases, the addition of glyphosate reduced the translocation of [(14)C]saflufenacil in glyphosate-susceptible plants, while translocation was not affected in glyphosate-resistant canola. Moreover, the phytotoxicity of saflufenacil reduced the activity of glyphosate, possibly by reducing its translocation in all plant species studied. Increased absorption of saflufenacil by the addition of Transorb (i.e., Transorb formulation with glyphosate) plus Merge appears to increase its contact activity, thus the interaction of saflufenacil and glyphosate involves two separate processes, absorption and translocation.

Ashigh J; Hall JC

2010-06-01

17

Bases for interactions between saflufenacil and glyphosate in plants.  

Science.gov (United States)

Buckwheat (Fagropyrum esculentum Moench.), cabbage (Brassica oleracea L), and conventional and glyphosate-resistant varieties of canola (Brassica napus L.) were used to study the bases of saflufenacil and glyphosate interactions. Compared to the addition of Merge (surfactant), the addition of both Transorb (i.e., commercial product, Transorb formulation with glyphosate) and Merge increased the cuticular absorption of [(14)C] saflufenacil in cabbage plants with thick epicuticular wax layers. However, in all cases, the addition of glyphosate reduced the translocation of [(14)C]saflufenacil in glyphosate-susceptible plants, while translocation was not affected in glyphosate-resistant canola. Moreover, the phytotoxicity of saflufenacil reduced the activity of glyphosate, possibly by reducing its translocation in all plant species studied. Increased absorption of saflufenacil by the addition of Transorb (i.e., Transorb formulation with glyphosate) plus Merge appears to increase its contact activity, thus the interaction of saflufenacil and glyphosate involves two separate processes, absorption and translocation. PMID:20481603

Ashigh, Jamshid; Hall, J Christopher

2010-06-23

18

Fluorescence enhancement of CdTe/CdS quantum dots by coupling of glyphosate and its application for sensitive detection of copper ion  

International Nuclear Information System (INIS)

Graphical abstract: Glyphosate (Glyp) had been used to modify the surface of CdTe/CdS QDs, resulting in the enhancement of fluorescence intensity. The Glyp-functionalized QDs fluorescent probe offers good sensitivity and selectivity for detecting Cu2+ based on the fluorescence quenching. Highlights: ? Water soluble CdTe/CdS quantum dots capped with glyphosate were firstly synthesized. ? The fluorescence of the Glyp-functionalized QDs was quenched by copper ion. ? A new fluorescent sensor for copper ion was developed based on the prepared QDs. ? The sensor exhibited high sensitivity and good selectivity for copper ion. - Abstract: A novel fluorescent probe for Cu2+ determination based on the fluorescence quenching of glyphosate (Glyp)-functionalized quantum dots (QDs) was firstly reported. Glyp had been used to modify the surface of QDs to form Glyp-functionalized QDs following the capping of thioglycolic acid on the core–shell CdTe/CdS QDs. Under the optimal conditions, the response was linearly proportional to the concentration of Cu2+ between 2.4 × 10?2 ?g mL?1 and 28 ?g mL?1, with a detection limit of 1.3 × 10?3 ?g mL?1 (3?). The Glyp-functionalized QDs fluorescent probe offers good sensitivity and selectivity for detecting Cu2+. The fluorescent probe was successfully used for the determination of Cu2+ in environmental samples. The mechanism of reaction was also discussed.

2012-10-01

19

Preparation method of glyphosate technicals  

UK PubMed Central (United Kingdom)

The invention relates to a preparation method of multiple glyphosate technicals, comprising the following steps: 1) adopting chloroacetic acid, glycine or ethanolamine as raw material and combining phosphorous acid and formaldehyde used as raw material to react to synthesize glyphosate 2) adopting iminodiacetonirile or diethanol amine as raw material to first synthesize N,N-(phosphonomethyl)diaminonitrile or N,N-(phosphonomethyl)diglycinol and then perform hydrolysis reaction to synthesize N-phosphonomethyliminodiacetic acid without through generating diglycolamidic acid and performing oxydrolysis reaction by one step to synthesize glyphosate. Compared with the existing glyphosate production process, the new process reduces 30% of energy consumption, 80% of wastewater discharge and 5% of raw material cost.

JIAN LI

20

Effect of glyphosate on ethylene production in tobacco callus.  

UK PubMed Central (United Kingdom)

Glyphosate (N-phosphonomethylglycine) caused a significant decrease or a slight increase in ethylene production in tobacco callus (Nicotiana tabacum L.) depending on the concentration of indole-3-acetic acid (IAA) present in the medium. IAA stimulated ethylene production, but a pretreatment with glyphosate greatly reduced the IAA-induced ethylene production. Inasmuch as glyphosate treatment promoted the metabolism of IAA, the decrease in ethylene production induced by glyphosate is attributed to the rapid loss of free IAA in the treated tissue.

Lee TT; Dumas T

1983-07-01

 
 
 
 
21

Fluorescence enhancement of CdTe/CdS quantum dots by coupling of glyphosate and its application for sensitive detection of copper ion  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: Glyphosate (Glyp) had been used to modify the surface of CdTe/CdS QDs, resulting in the enhancement of fluorescence intensity. The Glyp-functionalized QDs fluorescent probe offers good sensitivity and selectivity for detecting Cu{sup 2+} based on the fluorescence quenching. Highlights: Black-Right-Pointing-Pointer Water soluble CdTe/CdS quantum dots capped with glyphosate were firstly synthesized. Black-Right-Pointing-Pointer The fluorescence of the Glyp-functionalized QDs was quenched by copper ion. Black-Right-Pointing-Pointer A new fluorescent sensor for copper ion was developed based on the prepared QDs. Black-Right-Pointing-Pointer The sensor exhibited high sensitivity and good selectivity for copper ion. - Abstract: A novel fluorescent probe for Cu{sup 2+} determination based on the fluorescence quenching of glyphosate (Glyp)-functionalized quantum dots (QDs) was firstly reported. Glyp had been used to modify the surface of QDs to form Glyp-functionalized QDs following the capping of thioglycolic acid on the core-shell CdTe/CdS QDs. Under the optimal conditions, the response was linearly proportional to the concentration of Cu{sup 2+} between 2.4 Multiplication-Sign 10{sup -2} {mu}g mL{sup -1} and 28 {mu}g mL{sup -1}, with a detection limit of 1.3 Multiplication-Sign 10{sup -3} {mu}g mL{sup -1} (3{delta}). The Glyp-functionalized QDs fluorescent probe offers good sensitivity and selectivity for detecting Cu{sup 2+}. The fluorescent probe was successfully used for the determination of Cu{sup 2+} in environmental samples. The mechanism of reaction was also discussed.

Liu Zhengqing; Liu Shaopu; Yin Pengfei [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); He Youqiu, E-mail: heyq@swu.edu.cn [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)

2012-10-01

22

RENOVATING PASTURES WITH GLYPHOSATE TOLERANT SOYBEANS  

Science.gov (United States)

Reducing costs, reducing risk of failure, and producing income from pasture land during renovation can significantly increase the profitability of improving pastures. Technology developed for soybean production can be used to renovate pasture. Roundup® ready (glyphosate; N-(phosphonomethyl)glycine)...

23

Control of volunteer glyphosate-tolerant maize (Zea mays) in glyphosate-tolerant soybean (Glycine max).  

UK PubMed Central (United Kingdom)

Glyphosate-tolerant volunteer maize (Zea mays L.) has become a problem when glyphosate-tolerant soybean Glycine max (L.) Merr. follows glyphosate-tolerant maize in a crop rotation. A total of four field trials were conducted at Exeter, Ontario over a 2-year period (2003 and 2004) to evaluate the control of glyphosate-tolerant volunteer maize in glyphosate-tolerant soybean. Treatments consisted of postemergence (POST) glyphosate at 900 g ae/ha alone (control) and in tank-mix with clethodim (at 15, 22.5 and 30 g ai/ha), fenoxaprop-p-ethyl (at 27, 40.5 and 54 g ai/ha), fluazifop-p-butyl (at 37.5, 56.2 and 75 g ai/ha), quizalofop-p-ethyl (at 18, 27 and 36 g ai/ha), or sethoxydim (at 75, 112.5 and 150 g ai/ha). Glyphosate tank-mixed with clethodim, fenoxaprop-p-ethyl, fluazifop-p-butyl, quizalofop-p-ethyl, and sethoxydim did not injure the soybean and controlled volunteer maize. Glyphosate-tolerant volunteer maize density and dry weight were reduced with clethodim, fenoxaprop-p-ethyl, fluazifop-p-butyl, quizalofop-p-ethyl, and sethoxydim, but sethoxydim did not provide control of glyphosate-tolerant volunteer maize equivalent to the other herbicides evaluated. There was a decrease in control as the dose of clethodim, fenoxaprop-p-ethyl, fluazifop-p-butyl, and sethoxydim were reduced. There was no dose response with quizalofop-p-ethyl. Soybean yields closely reflected the level of glyphosate-tolerant volunteer maize control achieved. Based on these results, clethodim, fenoxaprop-p-ethyl, fluazifop-p-butyl, and quizalofop-p-ethyl at the recommended dose can be used to effectively control glyphosate-tolerant volunteer maize in glyphosate-tolerant soybean under Ontario growing conditions.

Soltani N; Shropshire C; Sikkema PH

2006-02-01

24

Glyphosate effects on the gene expression of the apical bud in soybean (Glycine max).  

UK PubMed Central (United Kingdom)

Glyphosate is a broad spectrum, non-selective herbicide which has been widely used for weed control. Much work has focused on elucidating the high accumulation of glyphosate in shoot apical bud (shoot apex). However, to date little is known about the molecular mechanisms of the sensitivity of shoot apical bud to glyphosate. Global gene expression profiling of the soybean apical bud response to glyphosate treatment was performed in this study. The results revealed that the glyphosate inhibited tryptophan biosynthesis of the shikimic acid pathway in the soybean apical bud, which was the target site of glyphosate. Glyphosate inhibited the expression of most of the target herbicide site genes. The promoter sequence analysis of key target genes revealed that light responsive elements were important regulators in glyphosate induction. These results will facilitate further studies of cloning genes and molecular mechanisms of glyphosate on soybean shoot apical bud.

Jiang LX; Jin LG; Guo Y; Tao B; Qiu LJ

2013-08-01

25

Glyphosate effects on the gene expression of the apical bud in soybean (Glycine max).  

Science.gov (United States)

Glyphosate is a broad spectrum, non-selective herbicide which has been widely used for weed control. Much work has focused on elucidating the high accumulation of glyphosate in shoot apical bud (shoot apex). However, to date little is known about the molecular mechanisms of the sensitivity of shoot apical bud to glyphosate. Global gene expression profiling of the soybean apical bud response to glyphosate treatment was performed in this study. The results revealed that the glyphosate inhibited tryptophan biosynthesis of the shikimic acid pathway in the soybean apical bud, which was the target site of glyphosate. Glyphosate inhibited the expression of most of the target herbicide site genes. The promoter sequence analysis of key target genes revealed that light responsive elements were important regulators in glyphosate induction. These results will facilitate further studies of cloning genes and molecular mechanisms of glyphosate on soybean shoot apical bud. PMID:23845904

Jiang, Ling-Xue; Jin, Long-Guo; Guo, Yong; Tao, Bo; Qiu, Li-Juan

2013-07-08

26

Occurrence of glyphosate in surface waters of Southern Ontario.  

UK PubMed Central (United Kingdom)

Glyphosate in surface waters of southern Ontario (Canada) was studied over a 2-year period. A small percentage of samples exhibited glyphosate concentrations greater than the analytical limit of quantitation (17 microg a.e./L), and the maximum concentration of glyphosate measured was 40.8 microg/L. No samples of roughly 500 analyzed exceeded the Canadian Water Quality Guideline of 65 microg a.e./L considered protective of aquatic life. Typical concentrations of glyphosate in amphibian habitats were well below a range of toxicity thresholds for aquatic organisms, and were thus judged to be unlikely to pose a substantial risk to either sensitive amphibian larvae or other aquatic biota.

Struger J; Thompson D; Staznik B; Martin P; McDaniel T; Marvin C

2008-04-01

27

Efecto del glifosato sobre el crecimiento y acumulación de azúcares libres en dos biotipos de lolium perenne de distinta sensibilidad al herbicida/ Glyphosate effects on the growth and free sugar accumulation of two lolium perenn e biotypes with different herbicide sensitivity  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish El movimiento sistémico del glifosato está determinado por el transporte de fotoasimilados. A su vez, la capacidad de un destino de consumir los asimilados está condicionada por su actividad metabólica. Pese a su importancia, la relación entre el glifosato y la síntesis de azúcares en hojas fuente ha sido poco abordada. El objetivo del presente trabajo fue evaluar los efectos del glifosato sobre el crecimiento y la acumulación de azúcares libres en dos biotipos d (more) e Lolium perenne de baja y alta sensibilidad al herbicida. Se trabajó con clones de ambos tipos de plantas, en macollaje, tratados con 1.440 g e.a. ha-1 de glifosato y sin tratamiento herbicida como controles. Se evaluó periódicamente el efecto del glifosato sobre el rebrote de hojas hasta las 50 horas post-aplicación y sobre los niveles de azúcares libres totales, reductores y no reductores en hojas a 1, 2, 3 y 5 días post-aplicación. A partir de las 25 horas post-aplicación, el glifosato provocó una disminución del crecimiento del 58% en el biotipo susceptible, con una acumulación de azúcares libres superior al 90% con relación al control, desde el primer día post-aplicación en adelante. La inhibición del crecimiento, inducida por el glifosato en plantas susceptibles, no depende de la limitación del traslado de fotoasimilados desde la parte aérea. Por tanto, la acumulación de azúcares libres en hojas podría explicarse por la caída en la tasa de crecimiento. En el biotipo de baja sensibilidad, en el que no se detectó inhibición del crecimiento, estos efectos fueron limitados. Abstract in english The systemic movement of glyphosate is determined by the transport of photoassimilates. In turn, the capacity of a destination to consume assimilates is conditioned by their metabolic activity. Despite its importance, the relationship between the glyphosate and the sugar synthesis from source leaves has been little studied. The aim of this work was to determine the effect of glyphosate on the growth and free sugar accumulation of two Lolium perenne biotypes of low and hig (more) h glyphosate sensitivity. It was worked with clones of both types, in tillering, sprayed with 1,440 g a.e. ha-1 of glyphosate as treatments and without herbicide as controls. The glyphosate effects on the regrowth of leaves was studied until 50 hours post-application and on total free sugar, reducing free sugar and nonreducing free sugar from leaves to 1, 2, 3 and 5 days post-application were periodically evaluated. From 25 hours after glyphosate application, it caused on the susceptible biotype a growth decrease of 58% and an accumulation of free sugar above 90% compared to controls. In susceptible biotypes, growth inhibition does not depend on a reduced photoassimilate translocation from the overground part. Therefore, the free sugar accumulation in leaves could be explained by the fall in the rate of growth. These effects are limited in the low sensitivity biotype, where growth inhibition has not been detected.

Yanniccari, M.; Istilart, C.; Giménez, D.O.; Acciaresi, H.; Castro, A.M

2012-03-01

28

Efecto del glifosato sobre el crecimiento y acumulación de azúcares libres en dos biotipos de lolium perenne de distinta sensibilidad al herbicida Glyphosate effects on the growth and free sugar accumulation of two lolium perenn e biotypes with different herbicide sensitivity  

Directory of Open Access Journals (Sweden)

Full Text Available El movimiento sistémico del glifosato está determinado por el transporte de fotoasimilados. A su vez, la capacidad de un destino de consumir los asimilados está condicionada por su actividad metabólica. Pese a su importancia, la relación entre el glifosato y la síntesis de azúcares en hojas fuente ha sido poco abordada. El objetivo del presente trabajo fue evaluar los efectos del glifosato sobre el crecimiento y la acumulación de azúcares libres en dos biotipos de Lolium perenne de baja y alta sensibilidad al herbicida. Se trabajó con clones de ambos tipos de plantas, en macollaje, tratados con 1.440 g e.a. ha-1 de glifosato y sin tratamiento herbicida como controles. Se evaluó periódicamente el efecto del glifosato sobre el rebrote de hojas hasta las 50 horas post-aplicación y sobre los niveles de azúcares libres totales, reductores y no reductores en hojas a 1, 2, 3 y 5 días post-aplicación. A partir de las 25 horas post-aplicación, el glifosato provocó una disminución del crecimiento del 58% en el biotipo susceptible, con una acumulación de azúcares libres superior al 90% con relación al control, desde el primer día post-aplicación en adelante. La inhibición del crecimiento, inducida por el glifosato en plantas susceptibles, no depende de la limitación del traslado de fotoasimilados desde la parte aérea. Por tanto, la acumulación de azúcares libres en hojas podría explicarse por la caída en la tasa de crecimiento. En el biotipo de baja sensibilidad, en el que no se detectó inhibición del crecimiento, estos efectos fueron limitados.The systemic movement of glyphosate is determined by the transport of photoassimilates. In turn, the capacity of a destination to consume assimilates is conditioned by their metabolic activity. Despite its importance, the relationship between the glyphosate and the sugar synthesis from source leaves has been little studied. The aim of this work was to determine the effect of glyphosate on the growth and free sugar accumulation of two Lolium perenne biotypes of low and high glyphosate sensitivity. It was worked with clones of both types, in tillering, sprayed with 1,440 g a.e. ha-1 of glyphosate as treatments and without herbicide as controls. The glyphosate effects on the regrowth of leaves was studied until 50 hours post-application and on total free sugar, reducing free sugar and nonreducing free sugar from leaves to 1, 2, 3 and 5 days post-application were periodically evaluated. From 25 hours after glyphosate application, it caused on the susceptible biotype a growth decrease of 58% and an accumulation of free sugar above 90% compared to controls. In susceptible biotypes, growth inhibition does not depend on a reduced photoassimilate translocation from the overground part. Therefore, the free sugar accumulation in leaves could be explained by the fall in the rate of growth. These effects are limited in the low sensitivity biotype, where growth inhibition has not been detected.

M. Yanniccari; C. Istilart; D.O. Giménez; H. Acciaresi; A.M Castro

2012-01-01

29

76 FR 19701 - Glyphosate (N-  

Science.gov (United States)

...residues of both gyphosate and its metabolite N-acetyl glyphosate. N- acetyl glyphosate is found in genetically modified (GMO) glyphosate- resistant commodities, including corn and soybeans; that are used as feed items for poultry in the U.S....

2011-04-08

30

Reduced sensitivity RDX obtained from bachmann RDX  

Energy Technology Data Exchange (ETDEWEB)

In recent years much interest has been generated in a quality of reduced sensitivity RDX (RS-RDX), like I-RDX {sup registered} which, when incorporated in cast cure and even pressable plastic bonded explosives (PBX compositions), can confer reduced shock sensitivity as measured through gap test. At crystal level, lot of work has been done to try to determine which property or properties may explain the behaviour of the corresponding cast PBX composition. But up to now, and despite an international inter-laboratory comparison (Round Robin) of seven lots of RDX from five different manufacturers conducted from 2003 to 2005, even if some techniques lead to interesting results, there is no dedicated specification to apply to RS-RDX. This quality (I-RDX {sup registered}) has proved to retain its low sensitivity even after ageing, which does not seem to be the case for standard RDX produced by the Bachmann process (when re-crystallized under I-RDX conditions in order to obtain RS-RDX). It has been shown that the higher sensitivity of RDX produced by the Bachmann process, or the evolution of sensitivity after ageing of RS-RDX produced from Bachmann RDX may be linked to the presence of octogen (HMX) during the crystallization process. In order to check such hypothesis, low HMX content RDX produced by the Bachmann process has been prepared and evaluated in cast PBX composition (PBX N 109). Results of the characterization of such quality of RDX and its evaluation in cast PBX composition as well as ageing behaviour are presented and discussed; there are indications that removal of HMX from Bachmann RDX may lead to RS-RDX, which retains its RS character even after ageing. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Spyckerelle, Christian; Eck, Genevieve [EURENCO France, Sorgues Plant 1928 route d' Avignon, BP 311, 84706 Sorgues Cedex (France); Sjoeberg, Per; Amneus, Anna-Maria [EURENCO Sweden, SE-69186 Karlskoga (Sweden)

2008-02-15

31

Effect of glyphosate on ethylene production in tobacco callus.  

Science.gov (United States)

Glyphosate (N-phosphonomethylglycine) caused a significant decrease or a slight increase in ethylene production in tobacco callus (Nicotiana tabacum L.) depending on the concentration of indole-3-acetic acid (IAA) present in the medium. IAA stimulated ethylene production, but a pretreatment with glyphosate greatly reduced the IAA-induced ethylene production. Inasmuch as glyphosate treatment promoted the metabolism of IAA, the decrease in ethylene production induced by glyphosate is attributed to the rapid loss of free IAA in the treated tissue. PMID:16663098

Lee, T T; Dumas, T

1983-07-01

32

Hormesis with glyphosate depends on coffee growth stage.  

Science.gov (United States)

Weed management systems in almost all Brazilian coffee plantations allow herbicide spray to drift on crop plants. In order to evaluate if there is any effect of the most commonly used herbicide in coffee production, glyphosate, on coffee plants, a range of glyphosate doses were applied directly on coffee plants at two distinct plant growth stages. Although growth of both young and old plants was reduced at higher glyphosate doses, low doses caused no effects on growth characteristics of young plants and stimulated growth of older plants. Therefore, hormesis with glyphosate is dependent on coffee plant growth stage at the time of herbicide application. PMID:23828346

De Carvalho, Leonardo B; Alves, Pedro L C A; Duke, Stephen O

33

Hormesis with glyphosate depends on coffee growth stage.  

UK PubMed Central (United Kingdom)

Weed management systems in almost all Brazilian coffee plantations allow herbicide spray to drift on crop plants. In order to evaluate if there is any effect of the most commonly used herbicide in coffee production, glyphosate, on coffee plants, a range of glyphosate doses were applied directly on coffee plants at two distinct plant growth stages. Although growth of both young and old plants was reduced at higher glyphosate doses, low doses caused no effects on growth characteristics of young plants and stimulated growth of older plants. Therefore, hormesis with glyphosate is dependent on coffee plant growth stage at the time of herbicide application.

De Carvalho LB; Alves PL; Duke SO

2013-04-01

34

Efeitos de diferentes formulações comerciais de glyphosate sobre estirpes de Bradyrhizobium Effects of different glyphosate commercial formulations on Bradyrhizobium strains  

Directory of Open Access Journals (Sweden)

Full Text Available O objetivo deste trabalho foi avaliar efeitos de formulações comerciais de glyphosate sobre estirpes de Bradyrhizobium, em condições de laboratório. As formulações foram aplicadas na concentração de 43,2 µg L-1 do equivalente ácido. As bactérias foram inoculadas em meio de cultura à base de manitol e extrato de levedura (YM). O efeito do herbicida no crescimento das estirpes de Bradyrhizobium foi avaliado mediante leitura da densidade ótica em espectrofotômetro. Avaliou-se o crescimento das estirpes de B. japonicum SEMIA 5079 e de B. elkanii SEMIA 5019 e SEMIA 587 sob efeito de nove formulações de glyphosate: Zapp Qi®, Roundup®, Roundup Multiação®, Roundup Transorb®, Roundup WG®, Trop®, Agrisato®, glyphosate técnico [padrão de N-(phosphonomethyl) glycina] e controle sem adição de herbicida (testemunha para as estirpes). Foram utilizadas seis repetições. Confeccionaram-se curvas de crescimento para cada estirpe. Pelos resultados, pôde-se observar que todas as formulações de glyphosate causaram efeitos diferenciados sobre as estirpes de Bradyrhizobium SEMIA 5019, SEMIA 5079 e SEMIA 587. Constatou-se que a formulação Zapp Qi foi a menos tóxica às estirpes de Bradyrhizobium avaliadas. A maior toxicidade foi observada para Roundup Transorb, que provocou reduções no crescimento acima de 94% para todas as estirpes de Bradyrhizobium estudadas. Não se observou correlação entre o tipo de sal - isopropilamina, amônio ou potássico, presentes na formulação herbicida - e o grau de inibição no crescimento das estirpes. SEMIA 587 foi a estirpe menos tolerante à maioria das formulações testadas, porém SEMIA 5019 foi a mais sensível ao glyphosate padrão, sem adição de sais ou de outros aditivos.This work aimed to evaluate the effects of glyphosate commercial formulations on Bradyrhizobium strains under laboratory conditions. The formulations were applied in the concentration of 43.2 µg L-1 of the a.e. and the strains were inoculated in yeast extract manitol (YM). Herbicide effect on the growth of the Bradyrhizobium strains was assessed by optic density reading in a spectrophotometer. Twenty seven treatments arranged in a factorial design were evaluated and consisted of one strain of B. japonicum: SEMIA 5079; and two strains of B. elkanii: SEMIA 5019 and SEMIA 587, under the effect of nine glyphosate formulations: Zapp QI®, Roundup®, Roundup Multiação®, Roundup Transorb®, Roundup WG®, Trop®, Agrisato®, technical glyphosate [N-(phosphonomethyl) glycine] and control without herbicide addition (as the strain control treatment), with six replications. A growth curve was established for each strain. It could be observed that the different glyphosate formulations Zapp Qi, Roundup, Roundup Multiação, Roundup transorb, Roundup WG, Trop and Agrisato caused differentiated effects on the strains of Bradyrhizobium SEMIA 5019, SEMIA 5079 and SEMIA 587. It was verified that the Zapp Qi formulation was the least toxic to the strains. The highest toxicity was observed for Roundup Transorb, which reduced growth over 94% for all the strains assessed. Correlation was not observed among the type of salt, isopropylamine, ammonium or potassic, present in the formulation herbicides, and the toxicity degree to the strains. The strain SEMIA 587 was the least tolerant to most formulations while SEMIA 5019 was the most sensitive to the control treatment N- (phosphonomethyl) glycine, without salts or other additives.

J.B. Santos; R.J.S. Jacques; S.O. Procópio; M.C.M. Kasuya; A.A. Silva; E.A. Santos

2004-01-01

35

Efeitos de diferentes formulações comerciais de glyphosate sobre estirpes de Bradyrhizobium/ Effects of different glyphosate commercial formulations on Bradyrhizobium strains  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O objetivo deste trabalho foi avaliar efeitos de formulações comerciais de glyphosate sobre estirpes de Bradyrhizobium, em condições de laboratório. As formulações foram aplicadas na concentração de 43,2 µg L-1 do equivalente ácido. As bactérias foram inoculadas em meio de cultura à base de manitol e extrato de levedura (YM). O efeito do herbicida no crescimento das estirpes de Bradyrhizobium foi avaliado mediante leitura da densidade ótica em espectrofotôm (more) etro. Avaliou-se o crescimento das estirpes de B. japonicum SEMIA 5079 e de B. elkanii SEMIA 5019 e SEMIA 587 sob efeito de nove formulações de glyphosate: Zapp Qi®, Roundup®, Roundup Multiação®, Roundup Transorb®, Roundup WG®, Trop®, Agrisato®, glyphosate técnico [padrão de N-(phosphonomethyl) glycina] e controle sem adição de herbicida (testemunha para as estirpes). Foram utilizadas seis repetições. Confeccionaram-se curvas de crescimento para cada estirpe. Pelos resultados, pôde-se observar que todas as formulações de glyphosate causaram efeitos diferenciados sobre as estirpes de Bradyrhizobium SEMIA 5019, SEMIA 5079 e SEMIA 587. Constatou-se que a formulação Zapp Qi foi a menos tóxica às estirpes de Bradyrhizobium avaliadas. A maior toxicidade foi observada para Roundup Transorb, que provocou reduções no crescimento acima de 94% para todas as estirpes de Bradyrhizobium estudadas. Não se observou correlação entre o tipo de sal - isopropilamina, amônio ou potássico, presentes na formulação herbicida - e o grau de inibição no crescimento das estirpes. SEMIA 587 foi a estirpe menos tolerante à maioria das formulações testadas, porém SEMIA 5019 foi a mais sensível ao glyphosate padrão, sem adição de sais ou de outros aditivos. Abstract in english This work aimed to evaluate the effects of glyphosate commercial formulations on Bradyrhizobium strains under laboratory conditions. The formulations were applied in the concentration of 43.2 µg L-1 of the a.e. and the strains were inoculated in yeast extract manitol (YM). Herbicide effect on the growth of the Bradyrhizobium strains was assessed by optic density reading in a spectrophotometer. Twenty seven treatments arranged in a factorial design were evaluated and cons (more) isted of one strain of B. japonicum: SEMIA 5079; and two strains of B. elkanii: SEMIA 5019 and SEMIA 587, under the effect of nine glyphosate formulations: Zapp QI®, Roundup®, Roundup Multiação®, Roundup Transorb®, Roundup WG®, Trop®, Agrisato®, technical glyphosate [N-(phosphonomethyl) glycine] and control without herbicide addition (as the strain control treatment), with six replications. A growth curve was established for each strain. It could be observed that the different glyphosate formulations Zapp Qi, Roundup, Roundup Multiação, Roundup transorb, Roundup WG, Trop and Agrisato caused differentiated effects on the strains of Bradyrhizobium SEMIA 5019, SEMIA 5079 and SEMIA 587. It was verified that the Zapp Qi formulation was the least toxic to the strains. The highest toxicity was observed for Roundup Transorb, which reduced growth over 94% for all the strains assessed. Correlation was not observed among the type of salt, isopropylamine, ammonium or potassic, present in the formulation herbicides, and the toxicity degree to the strains. The strain SEMIA 587 was the least tolerant to most formulations while SEMIA 5019 was the most sensitive to the control treatment N- (phosphonomethyl) glycine, without salts or other additives.

Santos, J.B.; Jacques, R.J.S.; Procópio, S.O.; Kasuya, M.C.M.; Silva, A.A.; Santos, E.A.

2004-06-01

36

IS AMINOMETHLYPHOSPHONIC ACID A METABOLITE OF GLYPHOSATE CAUSING INJURY IN GLYPHOSATE TREATED GLYPHOSATE-RESISTANT SOYBEAN  

Science.gov (United States)

Application of glyphosate to glyphosate-resistant (GR) soybean has resulted in significant injury under certain conditions. If GR soybean is completely resistant to glyphosate, injury could be caused by a metabolite of glyphosate. We hypothesized that GR soybean injury possibly results from the plan...

37

Gene amplification confers glyphosate resistance in Amaranthus palmeri.  

UK PubMed Central (United Kingdom)

The herbicide glyphosate became widely used in the United States and other parts of the world after the commercialization of glyphosate-resistant crops. These crops have constitutive overexpression of a glyphosate-insensitive form of the herbicide target site gene, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Increased use of glyphosate over multiple years imposes selective genetic pressure on weed populations. We investigated recently discovered glyphosate-resistant Amaranthus palmeri populations from Georgia, in comparison with normally sensitive populations. EPSPS enzyme activity from resistant and susceptible plants was equally inhibited by glyphosate, which led us to use quantitative PCR to measure relative copy numbers of the EPSPS gene. Genomes of resistant plants contained from 5-fold to more than 160-fold more copies of the EPSPS gene than did genomes of susceptible plants. Quantitative RT-PCR on cDNA revealed that EPSPS expression was positively correlated with genomic EPSPS relative copy number. Immunoblot analyses showed that increased EPSPS protein level also correlated with EPSPS genomic copy number. EPSPS gene amplification was heritable, correlated with resistance in pseudo-F(2) populations, and is proposed to be the molecular basis of glyphosate resistance. FISH revealed that EPSPS genes were present on every chromosome and, therefore, gene amplification was likely not caused by unequal chromosome crossing over. This occurrence of gene amplification as an herbicide resistance mechanism in a naturally occurring weed population is particularly significant because it could threaten the sustainable use of glyphosate-resistant crop technology.

Gaines TA; Zhang W; Wang D; Bukun B; Chisholm ST; Shaner DL; Nissen SJ; Patzoldt WL; Tranel PJ; Culpepper AS; Grey TL; Webster TM; Vencill WK; Sammons RD; Jiang J; Preston C; Leach JE; Westra P

2010-01-01

38

Glyphosate-Resistant Goosegrass from Mississippi  

Directory of Open Access Journals (Sweden)

Full Text Available A suspected glyphosate-resistant goosegrass [Eleusine indica (L.) Gaertn.] population, found in Washington County, Mississippi, was studied to determine the level of resistance and whether the resistance was due to a point mutation, as was previously identified in a Malaysian population. Whole plant dose response assays indicated a two- to four-fold increase in resistance to glyphosate. Leaf disc bioassays based on a glyphosate-dependent increase in shikimate levels indicated a five- to eight-fold increase in resistance. Sequence comparisons of messenger RNA for epsps, the gene encoding the enzyme 5-enolpyruvylshikimate-3-phosphate synthase, from resistant and sensitive goosegrass, revealed a cytosine to thymine nucleotide change at position 319 in the resistant accessions. This single nucleotide polymorphism causes a proline to serine amino acid substitution at position 106 in 5-enolpyruvylshikimate-3-phosphate synthase. A real-time polymerase chain reaction assay using DNA probes specific for the nucleotide change at position 319 was developed to detect this polymorphism. Goosegrass from 42 locations were screened, and the results indicated that glyphosate-resistant goosegrass remained localized to where it was discovered. Pendimethalin, s-metolachlor, clethodim, paraquat and fluazifop controlled resistant goosegrass 93% to 100%, indicating that several control options for glyphosate-resistant goosegrass are available.

William T. Molin; Alice A. Wright; Vijay K. Nandula

2013-01-01

39

Effects of additives on glyphosate activity in purple nutsedge  

International Nuclear Information System (INIS)

Effects of additives on 14 C-glyphosate penetration into purple nutsedge leaves were examined in the laboratory and efficacy of glyphosate for purple nutsedge control was studied in the greenhouse and field. The addition of (NH4)2 SO4 at 1.0% (v/v) + diesel oil at 1,0% (v/v) + Tendal at 1.0% (v/v) increased 14C-glyphosate penetration into nutsedge leaves more than the addition of either one alone. (NH4)2SO4 at 1.0% + diesel oil at 1.0% + Tendal at 0.12 or 0.25% increased the phytotoxicity of glyphosate at 0.5 and 0.75 kg, a.e./ha on nutsedge plants in the greenhouse but not in the field. Additives did not enhance glyphosate activity by reducing the number of nutsedae tubers. (author).

1998-01-01

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Redvine (Brunnichia ovata) and trumpetcreeper (Campsis radicans) management in glufosinate- and glyphosate-resistant soybean  

UK PubMed Central (United Kingdom)

Three field studies were conducted during 1998 to 2002 at Stoneville, MS, to examine the efficacy of glufosinate and glyphosate on redvine and trumpetcreeper control in glufosinate- and glyphosate-resistant soybean. Glyphosate at 2.52 kg ae/ha applied approximately 3 wk before planting soybean reduced trumpetcreeper density (45 to 52%) but not redvine compared with no glyphosate in both glufosinate- and glyphosate-resistant soybean. However, glyphosate applied preplant reduced biomass of both species in glufosinate-resistant soybean. Glyphosate early postemergence (EPOST) followed by (fb) late postemergence (LPOST) had no effect on redvine density but reduced trumpetcreeper density (70%) compared with the no-herbicide control. There were no differences in densities and biomass of redvine and trumpetcreeper and soybean yield among isopropylamine, diammonium, and aminomethanamide dihydrogen tetraoxosulfate salts of glyphosate. Overall, trumpetcreeper is more susceptible to glyphosate than redvine. Glufosinate EPOST with or without acifluorfen or glufosinate EPOST fb LPOST had no effect on densities of redvine and trumpetcreeper but reduced biomass 45 to 76% and 35 to 58%, respectively, compared with the nontreated control. These results show that glyphosate preplant and POST in-crop applications can reduce trumpetcreeper density but not redvine, and glufosinate POST applications can suppress growth of both species.

Reddy KN; Chachalis D

2004-10-01

 
 
 
 
41

Foliar Nickel Application Alleviates Detrimental Effects of Glyphosate Drift on Yield and Seed Quality of Wheat.  

UK PubMed Central (United Kingdom)

Glyphosate drift to non-target crops causes growth aberrations and yield losses. This herbicide can also interact with divalent nutrients and form poorly soluble complexes. The possibility of using nickel (Ni), an essential divalent metal, for alleviating glyphosate drift damage to wheat was investigated in this study. Effects of Ni applications on various growth parameters, seed yield and quality of durum wheat (Triticum durum) treated with sublethal glyphosate at different developmental stages were investigated in greenhouse experiments. Nickel concentrations of various plant parts and glyphosate-induced shikimate accumulation were measured. Foliar but not soil Ni applications significantly reduced glyphosate injuries including yield losses, stunting and excessive tillering. Both shoot and grain Ni concentrations were enhanced by foliar Ni treatment. Seed germination and seedling vigor were impaired by glyphosate and improved by foliar Ni application to parental plants. Foliar Ni application appears to have a great potential to ameliorate glyphosate drift injury to wheat.

Kutman BY; Kutman UB; Cakmak I

2013-07-01

42

Bacterial glyphosate resistance conferred by overexpression of an E. coli membrane efflux transporter.  

Science.gov (United States)

Glyphosate herbicide-resistant crop plants, introduced commercially in 1994, now represent approximately 85% of the land area devoted to transgenic crops. Herbicide resistance in commercial glyphosate-resistant crops is due to expression of a variant form of a bacterial 5-enolpyruvylshikimate-3-phosphate synthase with a significantly decreased binding affinity for glyphosate at the target site of the enzyme. As a result of widespread and recurrent glyphosate use, often as the only herbicide used for weed management, increasing numbers of weedy species have evolved resistance to glyphosate. Weed resistance is most often due to changes in herbicide translocation patterns, presumed to be through the activity of an as yet unidentified membrane transporter in plants. To provide insight into glyphosate resistance mechanisms and identify a potential glyphosate transporter, we screened Escherichia coli genomic DNA for alternate sources of glyphosate resistance genes. Our search identified a single non-target gene that, when overexpressed in E. coli and Pseudomonas, confers high-level glyphosate resistance. The gene, yhhS, encodes a predicted membrane transporter of the major facilitator superfamily involved in drug efflux. We report here that an alternative mode of glyphosate resistance in E. coli is due to reduced accumulation of glyphosate in cells that overexpress this membrane transporter and discuss the implications for potential alternative resistance mechanisms in other organisms such as plants. PMID:22089966

Staub, Jeffrey M; Brand, Leslie; Tran, Minhtien; Kong, Yifei; Rogers, Stephen G

2011-11-17

43

Bacterial glyphosate resistance conferred by overexpression of an E. coli membrane efflux transporter.  

UK PubMed Central (United Kingdom)

Glyphosate herbicide-resistant crop plants, introduced commercially in 1994, now represent approximately 85% of the land area devoted to transgenic crops. Herbicide resistance in commercial glyphosate-resistant crops is due to expression of a variant form of a bacterial 5-enolpyruvylshikimate-3-phosphate synthase with a significantly decreased binding affinity for glyphosate at the target site of the enzyme. As a result of widespread and recurrent glyphosate use, often as the only herbicide used for weed management, increasing numbers of weedy species have evolved resistance to glyphosate. Weed resistance is most often due to changes in herbicide translocation patterns, presumed to be through the activity of an as yet unidentified membrane transporter in plants. To provide insight into glyphosate resistance mechanisms and identify a potential glyphosate transporter, we screened Escherichia coli genomic DNA for alternate sources of glyphosate resistance genes. Our search identified a single non-target gene that, when overexpressed in E. coli and Pseudomonas, confers high-level glyphosate resistance. The gene, yhhS, encodes a predicted membrane transporter of the major facilitator superfamily involved in drug efflux. We report here that an alternative mode of glyphosate resistance in E. coli is due to reduced accumulation of glyphosate in cells that overexpress this membrane transporter and discuss the implications for potential alternative resistance mechanisms in other organisms such as plants.

Staub JM; Brand L; Tran M; Kong Y; Rogers SG

2012-04-01

44

Translocação do glyphosate em biótipos de azevém (Lolium multiflorum)/ Glyphosate translocation in Italian ryegrass biotypes (Lolium multiflorum)  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Foram avaliadas neste trabalho a absorção foliar e a translocação do glyphosate por biótipos de azevém (Lolium multiflorum) sensíveis e resistentes a esse herbicida. Para isso, aplicou-se 14C-glyphosate utilizando-se uma microsseringa de precisão, adicionando-se 10 µL da calda sobre a face adaxial da primeira folha com lígula totalmente visível, quando as plantas de azevém se apresentavam com três perfilhos. A quantidade de glyphosate absorvido e translocado (more) foi avaliada em intervalos de tempo (2, 4, 8, 16, 32 e 64 horas após a aplicação), por meio da medição da radiação emitida pelo 14C-glyphosate, em espectrômetro de cintilação líquida. Foram analisadas a parte aérea e as raízes, bem como a folha onde foi feita a aplicação e a solução de lavagem desta folha. A velocidade de absorção do glyphosate foi semelhante em ambos os biótipos de azevém, observando-se mais de 50% de absorção desse herbicida nas primeiras oito horas após a aplicação. Maior retenção de glyphosate foi observada na folha tratada do biótipo resistente: 81,64% do total de glyphosate absorvido até as 64 horas. No biótipo sensível esse valor foi de 55% no mesmo período. No restante da parte aérea e nas raízes, a maior quantidade do glyphosate absorvido foi encontrada no biótipo sensível, mostrando sua maior capacidade de translocação. Após 64 horas da aplicação do glyphosate, apenas 6%, em média, do glyphosate se encontrava nas plantas, indicando que a maior parte do produto pode ter sido exsudada. Conclui-se que a sensibilidade do azevém ao glyphosate pode ser atribuída à maior capacidade de translocação desse herbicida pelo biótipo sensível. Abstract in english This work evaluated foliar absorption and glyphosate translocation in Italian ryegrass (Lolium multiflorum) susceptible and resistant biotypes, 14C-glyphosate was applied by using a precision micro syringe, and adding 10 µL of solution on the adaxial side of the first leaf with ligule totally visible, when Italian ryegrass plants showed 3 tillers. The quantity of glyphosate absorbed and translocated was evaluated through a liquid scintilation spectrometer by measuring ra (more) diation emitted by 14C-glyphosate at 2, 4, 8, 16, 32 and 64 hours after application. The roots and aerial part were analyzed as well as the leaf where application was performed and the solution used to wash the leaf. Glyphosate absorption speed was similar in both Italian ryegrass biotypes, with over 50% of herbicide absorption in the first 8 hours after application. Up to 64 hours, higher retention (81.64%)of glyphosate was observed in the resistant biotype, while only 55% was retained in the susceptible biotype. In the remaining aerial part and roots, a higher amount of glyphosate was absorbed by the susceptible biotype, indicating higher capacity of its translocation. After 64 hours of application, only 6%, of glyphosate was found in the plants, on average indicating that most of the product could be exuded. It could be concluded that Italian ryegrass sensitivity to glyphosate can be attributed to higher translocation capacity of this herbicide by susceptible biotypes.

Ferreira, E.A.; Santos, J.B.; Silva, A.A.; Oliveira, J.A.; Vargas, L.

2006-06-01

45

Aggregation of Explosives for Reduced Sensitiveness.  

Science.gov (United States)

Very small particles of explosives are less sensitive to impact than larger particles. However, such small RDX particles in TNT give a high melt viscosity. This task was aimed at binding the very small particles together to give aggregates that would not ...

W. W. Hillstrom L. J. Vande Kieft E. J. Pacanowsky

1982-01-01

46

Reduced taste sensitivity in congenital blindness.  

UK PubMed Central (United Kingdom)

Sight is undoubtedly not only important for food identification and selection but also for the modulation of gustatory sensitivity. We can, therefore, assume that taste sensitivity and eating habits are affected by visual deprivation from birth. We measured taste detection and identification thresholds of the 5 basic tastants in 13 congenitally blind and 13 sighted control subjects. Participants also answered several eating habits questionnaires, including the Food Neophobia Scale, the Food Variety Seeking Tendency Scale, the Intuitive Eating Scale, and the Body Awareness Questionnaire. Our behavioral results showed that compared with the normal sighted, blind subjects have increased thresholds for taste detection and taste identification. This finding is at odds with the superior performance of congenitally blind subjects in several tactile, auditory and olfactory tasks. Our psychometric data further indicate that blind subjects more strongly rely on internal hunger and satiety cues, instead of external contextual or emotional cues, to decide when and what to eat. We suggest that the lower taste sensitivity observed in congenitally blind individuals is due to various blindness-related obstacles when shopping for food, cooking and eating out, all of which contribute to underexpose the gustatory system to a larger variety of taste stimuli.

Gagnon L; Kupers R; Ptito M

2013-07-01

47

Improved weed control with broadleaved herbicides in glyphosate-tolerant soybean (Glycine max)  

UK PubMed Central (United Kingdom)

Failure to control certain broadleaved weeds with glyphosate creates the need for other herbicides in glyphosate-tolerant soybean. Field studies were conducted in 2001, 2002 and 2003 to evaluate soybean yield response and control of Solanum sisymbrifolium Lam., Parietaria debilis Nutt., Commelina erecta L. and Sida rhombifolia L. with soil and foliar-applied broadleaved herbicides. Pre-emergence metribuzin, imazaquin and post-emergence imazethapyr and glyphosate controlled S. sisymbrifolium, C. erecta and S. rhombifolia. In 2002 and 2003, in glyphosate-treated plots surviving plants and those emerged along with the crop compete with soybean during 3 or 4 weeks after crop emergence thus reducing crop yield. Soil-applied herbicides may be beneficial for glyphosate-tolerant crops reducing early season competition of weeds, particularly those inherentely more tolerant to glyphosate.

Arregui MC; Scotta R; Sa?nchez D

2006-07-01

48

Nontarget mechanims involved in glyphosate tolerance found in Canavalia ensiformis plants.  

UK PubMed Central (United Kingdom)

A glyphosate-tolerant population of Canavalia ensiformis was collected in a cover crop in citrus orchards in Veracruz (Mexico), where glyphosate had been used for the first time. A susceptible Amaranthus hybridus L. population was collected from a nearby field that had never been treated with glyphosate. Dose-response experiments indicated a glyphosate tolerance ratio [ED(50)(C. ensiformis)/ED(50) (A. hybridus)] of 7.7. The hypothesis of a high level of glyphosate tolerance was provisionally corroborated on the basis of shikimate accumulation in both species. The susceptible population accumulated 6 times more shikimic acid in leaf tissue 96 h after glyphosate application than the tolerant leguminous crop. Two different physiological factors were involved in the glyphosate tolerance of this C. ensiformis population, which were confirmed by [(14)C]glyphosate, being a lack of penetration of glyphosate through the cuticle of the leguminous plants and an impaired herbicide translocation to the roots and the rest of shoots. This paper reports that two different nontarget site-based mechanisms, limited absorption and reduced translocation, contribute to the glyphosate tolerance found in C. ensiformis.

Cruz-Hipolito H; Osuna MD; Heredia A; Ruiz-Santaella JP; De Prado R

2009-06-01

49

Nontarget mechanims involved in glyphosate tolerance found in Canavalia ensiformis plants.  

Science.gov (United States)

A glyphosate-tolerant population of Canavalia ensiformis was collected in a cover crop in citrus orchards in Veracruz (Mexico), where glyphosate had been used for the first time. A susceptible Amaranthus hybridus L. population was collected from a nearby field that had never been treated with glyphosate. Dose-response experiments indicated a glyphosate tolerance ratio [ED(50)(C. ensiformis)/ED(50) (A. hybridus)] of 7.7. The hypothesis of a high level of glyphosate tolerance was provisionally corroborated on the basis of shikimate accumulation in both species. The susceptible population accumulated 6 times more shikimic acid in leaf tissue 96 h after glyphosate application than the tolerant leguminous crop. Two different physiological factors were involved in the glyphosate tolerance of this C. ensiformis population, which were confirmed by [(14)C]glyphosate, being a lack of penetration of glyphosate through the cuticle of the leguminous plants and an impaired herbicide translocation to the roots and the rest of shoots. This paper reports that two different nontarget site-based mechanisms, limited absorption and reduced translocation, contribute to the glyphosate tolerance found in C. ensiformis. PMID:19432449

Cruz-Hipolito, Hugo; Osuna, Maria D; Heredia, Antonio; Ruiz-Santaella, Juan Pedro; De Prado, Rafael

2009-06-10

50

Control of glyphosate resistant giant ragweed in soybean with preplant herbicides  

Directory of Open Access Journals (Sweden)

Full Text Available Giant ragweed was the first glyphosate resistant weed identified in Canada. It is a very competetive weed in row crop production and has been found to drastically reduce yields of soybean; therefore, control of this competitive weed is essential. The objective of this study was to determine effective control options for glyphosate resistant giant ragweed in soybean with herbicides applied preplant. Eighteen herbicide combinations were evaluated in field studies conducted in 2011 and 2012 at five locations with confirmed glyphosate resistant giant ragweed. Glyphosate plus 2,4-D ester or amitrole provided the best control of glyphosate resistant giant ragweed 4 WAA. Glyphosate plus 2,4-D ester provided 98 to 99% control and was equivalent to the weed free check at all locations. Glyphosate plus amitrole provided 90% to 93% control and was equivalent to the weed free check at 4 of 5 locations. Herbicides providing residual activity provided variable control across all locations. Of the herbicides with residual activity evaluated, glyphosate plus linuron provided the best control of glyphosate resistant giant ragweed; however, control was inconsistent across locations and years. Glyphosate plus linuron provided 23% to 99% controland was equal to the weed free check at one location 8 WAA.

Joanna Follings; Nader Soltani; Darren E. Robinson; François J. Tardif; Mark B. Lawton; Peter H. Sikkema

2013-01-01

51

Interaction of a bioherbicide and glyphosate for controlling hemp sesbania in glyphosate-resistant soybean  

UK PubMed Central (United Kingdom)

The bioherbicidal fungus, Colletotrichum truncatum (Schwein.) Andrus & Moore, was tested at different inoculum concentrations alone and in combination with, prior to or following treatment with different rates of glyphosate (N-[phosphonomethyl]glycine) (Roundup Ultra) for the control of hemp sesbania (Sesbania exaltata[Raf.] Rydb. ex A.W. Hill) in Roundup Ready soybean field plots. Colletotrichum truncatum and glyphosate were applied in all pair-wise combinations of 0, 1.25, 2.5, 5.0, and 10.0 x 10? spores mL?¹ (i.e. 3.125, 6.25, 12.5, and 25 x 10¹¹ spores ha?¹), and 0.15, 0.30, 0.60, and 1.2 kg ha?¹, respectively. Weed control and disease incidence were enhanced at the two lowest fungal and herbicidal rates when the fungal spores were applied after glyphosate treatment. The application of the fungus in combination with or prior to glyphosate application at 0.30 kg ha?¹ resulted in reduced disease incidence and weed control regardless of the inoculum's concentration. At the highest glyphosate rates, the weeds were controlled by the herbicide alone. These results suggest that it might be possible to utilize additive or synergistic herbicide and pathogen interactions to enhance hemp sesbania control.

Boyette CD; Hoagland RE; Weaver MA

2008-03-01

52

Reduced contrast sensitivity when viewing through an aircraft windscreen.  

UK PubMed Central (United Kingdom)

The Contrast Sensitivity Function (CSF) of an experienced observer was measured under normal viewing conditions, when looking through an aircraft windscreen and when looking through the windscreen in the presence of a glare source. We found that contrast sensitivity was significantly reduced for frequencies above about 6 cycles/degree viewed through the windscreen and that the addition of a glare source further reduced contrast sensitivity for all spatial frequencies greater than 1 cycle/degree. These results demonstrate that the CSF is a sensitive metric of degraded visual performance when viewing through optical transparencies.

Hughes PK; Vingrys AJ

1991-03-01

53

Glyphosate no controle de biótipos de azevém e impacto na microbiota do solo Glyphosate application for italian ryegrass biotype control and impact on soil microbiota  

Directory of Open Access Journals (Sweden)

Full Text Available Avaliou-se neste trabalho a resistência de azevém (L. multiflorum) ao glyphosate e o impacto do controle desses biótipos sobre a respiração e biomassa microbiana do solo. Foram conduzidos dois ensaios: no primeiro foram avaliadas a intoxicação e a massa seca das plantas de biótipos de três populações de azevém: população 1 (reconhecidamente resistente), população 2 (resistência intermediária), e população 3 (sensível ao glyphosate), submetidas a diferentes doses de glyphosate (200, 400, 800, 1.600 e 3.200 g ha-1). No segundo ensaio foram avaliados a massa seca da parte aérea, a altura de plantas, o número de folhas de azevém e a respiração e massa microbiana do solo cultivado com os biótipos resistente e sensível, com e sem aplicação de glyphosate (480 g ha-1). Aos 14 DAT, observou-se morte do biótipo sensível quando tratado com doses a partir de 200 g ha-1 de glyphosate. Nos biótipos resistentes e com nível intermediário de resistência, a toxicidade do glyphosate às plantas de azevém foi de 85% na maior dose avaliada. O biótipo resistente apresentou maior produção de massa seca da parte aérea aos 42 DAT e na rebrota, aos 72 DAT, quando comparado ao biótipo intermediário. O biótipo sensível apresentou maior altura de plantas, número de folhas e massa seca da parte aérea, em comparação ao resistente, quando não tratados com o glyphosate. Não foi observada diferença na atividade microbiana do solo entre os tratamentos avaliados.This study aimed to evaluate the resistance Italian ryegrass (L. multiflorum) against glyphosate and the impact of the control of these biotypes on soil respiration and microbial biomass. Two essays were conducted: the first evaluated intoxication and dry mass of the plants of biotypes of three Italian ryegrass population (population 1 - resistant; population 2 - intermediary resistance; and population 3 - sensitive to glyphosate) submitted to different glyphosate rates. The second assay evaluated dry matter of the aereal part, plant height, number of leaves and respiration and microbial mass of the soil cultivated with the resistant and sensitive biotypes, with and without glyphosate application (480 g ha-1). At 14 DAA, death of the susceptible biotype was observed, when treated with rates starting from 200 g ha-1 of glyphosate. The resistant ad intermediate resistant biotypes showed glyphosate phytotoxicity of 85% at the highest rate evaluated. The resistant biotype presented the highest dry matter production of the aerial part at 42 DAA and during sprouting, at 72 DAA, compared to the intermediary biotype. The sensitive biotype presented higher plant height, number of leaves and dry mass of the aerial part, to the resistant biotype, without glyphosate. No difference was observed in the microbial activity in the soil among the treatments.

E.A. Ferreira; J.B. Santos; A.A. Silva; L. Vargas; M.R. Reis

2006-01-01

54

Antagonismo na associação de glyphosate e triazinas Antagonism with glyphosate and triazine combinations  

Directory of Open Access Journals (Sweden)

Full Text Available No sistema de semeadura direta, há a necessidade de realizar o controle da vegetação existente na área antes da semeadura da cultura e também de utilizar herbicidas residuais para evitar a infestação de plantas daninhas no período inicial do desenvolvimento da cultura. É interesse dos agricultores utilizar herbicidas dessecantes e residuais simultaneamente, a fim de economizar tempo e recursos financeiros. O objetivo deste trabalho foi verificar a compatibilidade de glyphosate e triazinas quando associados no tanque do pulverizador. O experimento foi realizado em campo, na safra de crescimento 2001-2002. Utilizou-se como planta reagente o sorgo, híbrido Dekalb 865, semeado em novembro de 2001. Os tratamentos herbicidas foram aplicados 60 dias após a semeadura, quando as plantas estavam com 1,0 m, no início do emborrachamento. Os tratamentos consistiram de glyphosate nas doses de 540, 720 e 900 g ha-1, aplicado isoladamente ou associado a simazine + atrazine (Primatop SC) nas doses de 1.750 + 1.750 g ha-1. Também foram testados um tratamento sem herbicidas e outro apenas com o herbicida residual. As avaliações de controle e de teores de clorofila indicaram efeitos antagônicos para as três doses de glyphosate. Os efeitos antagônicos da associação dos herbicidas reduzem de intensidade com o aumento da dose do glyphosate ou com o decorrer do tempo.The no-tillage system requires herbicide spraying before planting to eliminate the existing weeds in the area and residual herbicides to prevent new weed infestation during the crop cycle. Farmers tend to spray both groups of herbicide simultaneously to reduce costs and application time. The objective of this work was to verify the compatibility of glyphosate and triazine as a tank mix. An experiment was conducted under field conditions during the 2001-2002 growing season, using sorghum as a model to evaluate the herbicide mixture compatibility. Sorghum hibrid Dekalb 865 was planted in November 2001 and the treatments were sprayed 60 days after planting, when the plants were 100 cm tall and at the boot stage. Treatments consisted of glyphosate at 540, 720 and 900 g ha-1, sprayed alone or in mixture with simazine + atrazine (Primatop SC) at 1750 + 1750 g ha-1. Treatments also included an untreated control and the residual herbicides used alone. The results of plant control and chlorophyll content indicated a severe antagonism in the glyphosate and triazine combination. Herbicide antagonism reduced with increment of glyphosate rate or at late assessment periods.

R.A. Vidal; M. Machry; G.C. Hernandes; N.G. Fleck

2003-01-01

55

Antagonismo na associação de glyphosate e triazinas/ Antagonism with glyphosate and triazine combinations  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese No sistema de semeadura direta, há a necessidade de realizar o controle da vegetação existente na área antes da semeadura da cultura e também de utilizar herbicidas residuais para evitar a infestação de plantas daninhas no período inicial do desenvolvimento da cultura. É interesse dos agricultores utilizar herbicidas dessecantes e residuais simultaneamente, a fim de economizar tempo e recursos financeiros. O objetivo deste trabalho foi verificar a compatibilidade (more) de glyphosate e triazinas quando associados no tanque do pulverizador. O experimento foi realizado em campo, na safra de crescimento 2001-2002. Utilizou-se como planta reagente o sorgo, híbrido Dekalb 865, semeado em novembro de 2001. Os tratamentos herbicidas foram aplicados 60 dias após a semeadura, quando as plantas estavam com 1,0 m, no início do emborrachamento. Os tratamentos consistiram de glyphosate nas doses de 540, 720 e 900 g ha-1, aplicado isoladamente ou associado a simazine + atrazine (Primatop SC) nas doses de 1.750 + 1.750 g ha-1. Também foram testados um tratamento sem herbicidas e outro apenas com o herbicida residual. As avaliações de controle e de teores de clorofila indicaram efeitos antagônicos para as três doses de glyphosate. Os efeitos antagônicos da associação dos herbicidas reduzem de intensidade com o aumento da dose do glyphosate ou com o decorrer do tempo. Abstract in english The no-tillage system requires herbicide spraying before planting to eliminate the existing weeds in the area and residual herbicides to prevent new weed infestation during the crop cycle. Farmers tend to spray both groups of herbicide simultaneously to reduce costs and application time. The objective of this work was to verify the compatibility of glyphosate and triazine as a tank mix. An experiment was conducted under field conditions during the 2001-2002 growing season (more) , using sorghum as a model to evaluate the herbicide mixture compatibility. Sorghum hibrid Dekalb 865 was planted in November 2001 and the treatments were sprayed 60 days after planting, when the plants were 100 cm tall and at the boot stage. Treatments consisted of glyphosate at 540, 720 and 900 g ha-1, sprayed alone or in mixture with simazine + atrazine (Primatop SC) at 1750 + 1750 g ha-1. Treatments also included an untreated control and the residual herbicides used alone. The results of plant control and chlorophyll content indicated a severe antagonism in the glyphosate and triazine combination. Herbicide antagonism reduced with increment of glyphosate rate or at late assessment periods.

Vidal, R.A.; Machry, M.; Hernandes, G.C.; Fleck, N.G.

2003-08-01

56

Sintomas da intoxicação inicial de Eucalyptus proporcionados por subdoses de glyphosate aplicadas no caule ou nas folhas/ Initial symptoms of Eucalyptus intoxication by glyphosate rates applied on the stem or leaves  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Com o objetivo de avaliar os sintomas de intoxicação causados pela aplicação de glyphosate, foi montado um estudo composto por quatro ensaios com aplicações de glyphosate (360 g e.a. L-1) em eucalipto. Em todos os ensaios, mudas foram transplantadas em vasos de 5,0 L. Nos ensaios 1 e 2, foram aplicados volumes crescentes de solução de glyphosate no caule do eucalipto. No ensaio 1, a solução de 3% (v/v) foi aplicada nos volumes de 0, 1, 5, 10, 20, 40, 80 e 160 µ (more) L de calda por planta e, no segundo, a solução de glyphosate a 2% (v/v) foi aplicada nos volumes de 0, 1, 5, 15, 30, 60, 90, 120 e 150 µL de calda por planta. Nos ensaios 3 e 4, foram feitas aplicações de glyphosate sobre as plantas de eucalipto. No ensaio 3, as doses foram de 0, 7,2.10-7, 7,2.10-6, 7,2.10-5, 7,2.10-4, 7,2.10-3, 7,2.10-2, 7,2.10-1, 7,2, 72, 360 e 720 g e.a. de glyphosate ha-1 e, no ensaio 4, de 0, 9, 18, 36, 72, 144, 288, 432, 576, 720, 1.080, 1.440 e 2.160 g e.a. de glyphosate ha-1. Nos quatro ensaios foi utilizado o delineamento DIC, com três repetições. Nas plantas, foram avaliadas a altura, a área foliar e a matéria seca de caule e folhas. Os resultados obtidos foram submetidos a análises de regressão. Quando aplicadas no caule, doses de 40,78 e 51,41 µL de calda por planta de glyphosate a 3 e 2% (v/v), respectivamente, nos ensaios 1 e 2, foram suficientes para redução média de 50% das características estudadas. Nas aplicações sobre as folhas, houve maior sensibilidade das plantas mais desenvolvidas. Para redução média de 50% nas variáveis analisadas, foram necessárias doses de 277,4 e 143,3 g e.a. de glyphosate ha-1 nos ensaios 3 e 4, respectivamente. Abstract in english This work was carried out to evaluate intoxication symptoms caused by glyphosate application. It was constituted by four assays with glyphosate applications (360 g a.e. L-1) on eucalyptus. In all assays, seedlings were transplanted into 5.OL plastic pots. In assays 1 and 2, increasing herbicide volumes were applied on the stem. In the first one, a glyphosate solution of 3% (v/v) was applied at the volumes 0, 1, 5, 10, 20, 40, 80 and 160 µL solution per plant, and in the (more) second, glyphosate solution of 2% (v/v) was applied at volumes 0, 1, 5, 15, 30, 60, 90, 120 and 150 µL solution per plant. In assays 3 and 4, glyphosate was sprayed on the plants. The rates in the third assay were: 0, 7.2 10-7, 7.2 10-6, 7.2 10-5, 7.2 10-4, 7.2 10-3, 7.2 10-2, 7.2 10-1, 7.2, 72, 360 and 720 g a.e. of glyphosate ha 1, and in the fourth assay, the rates were: 0, 9, 18, 36, 72, 144, 288, 432, 576, 720, 1.080, 1.440 and 2.160 g a.e. of glyphosate ha-1. All assays were arranged in a randomized design, with three replications. Height, leaf area, and dry mass of the leaves and stem were evaluated in the plants and the results were submitted to regression analysis. When applied on the stem, doses of 40.78 and 51.41 µL per plant of glyphosate solution, 3 and 2% (v/v), respectively, were sufficient to reduce eucalyptus development in 50%. When applied on the plants, more developed plants showed greater sensitivity.Rates of 277.4 and 143.3 g a.e. ha-1 reduced eucalyptus growth in 50%, in assays 3 and 4, respectively.

Salgado, T.P; Alves, P.L.C.A; Kuva, M.A; Takahashi, E.N; Dias, T.C.S; Lemes, L.N

2011-12-01

57

Isoflavone, glyphosate, and aminomethylphosphonic acid levels in seeds of glyphosate-treated, glyphosate-resistant soybean.  

Science.gov (United States)

The estrogenic isoflavones of soybeans and their glycosides are products of the shikimate pathway, the target pathway of glyphosate. This study tested the hypothesis that nonphytotoxic levels of glyphosate and other herbicides known to affect phenolic compound biosynthesis might influence levels of these nutraceutical compounds in glyphosate-resistant soybeans. The effects of glyphosate and other herbicides were determined on estrogenic isoflavones and shikimate in glyphosate-resistant soybeans from identical experiments conducted on different cultivars in Mississippi and Missouri. Four commonly used herbicide treatments were compared to a hand-weeded control. The herbicide treatments were (1) glyphosate at 1260 g/ha at 3 weeks after planting (WAP), followed by glyphosate at 840 g/ha at 6 WAP; (2) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied preemergence (PRE), followed by glyphosate at 1260 g/ha at 6 WAP; (3) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by glyphosate at 1260 g/ha at full bloom; and (4) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by acifluorfen at 280 g/ha plus bentazon at 560 g/ha plus clethodim at 140 g/ha at 6 WAP. Soybeans were harvested at maturity, and seeds were analyzed for daidzein, daidzin, genistein, genistin, glycitin, glycitein, shikimate, glyphosate, and the glyphosate degradation product, aminomethylphosphonic acid (AMPA). There were no remarkable effects of any treatment on the contents of any of the biosynthetic compounds in soybean seed from either test site, indicating that early and later season applications of glyphosate have no effects on phytoestrogen levels in glyphosate-resistant soybeans. Glyphosate and AMPA residues were higher in seeds from treatment 3 than from the other two treatments in which glyphosate was used earlier. Intermediate levels were found in treatments 1 and 2. Low levels of glyphosate and AMPA were found in treatment 4 and a hand-weeded control, apparently due to herbicide drift. PMID:12502430

Duke, Stephen O; Rimando, Agnes M; Pace, Patrick F; Reddy, Krishna N; Smeda, Reid J

2003-01-01

58

Isoflavone, glyphosate, and aminomethylphosphonic acid levels in seeds of glyphosate-treated, glyphosate-resistant soybean.  

UK PubMed Central (United Kingdom)

The estrogenic isoflavones of soybeans and their glycosides are products of the shikimate pathway, the target pathway of glyphosate. This study tested the hypothesis that nonphytotoxic levels of glyphosate and other herbicides known to affect phenolic compound biosynthesis might influence levels of these nutraceutical compounds in glyphosate-resistant soybeans. The effects of glyphosate and other herbicides were determined on estrogenic isoflavones and shikimate in glyphosate-resistant soybeans from identical experiments conducted on different cultivars in Mississippi and Missouri. Four commonly used herbicide treatments were compared to a hand-weeded control. The herbicide treatments were (1) glyphosate at 1260 g/ha at 3 weeks after planting (WAP), followed by glyphosate at 840 g/ha at 6 WAP; (2) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied preemergence (PRE), followed by glyphosate at 1260 g/ha at 6 WAP; (3) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by glyphosate at 1260 g/ha at full bloom; and (4) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by acifluorfen at 280 g/ha plus bentazon at 560 g/ha plus clethodim at 140 g/ha at 6 WAP. Soybeans were harvested at maturity, and seeds were analyzed for daidzein, daidzin, genistein, genistin, glycitin, glycitein, shikimate, glyphosate, and the glyphosate degradation product, aminomethylphosphonic acid (AMPA). There were no remarkable effects of any treatment on the contents of any of the biosynthetic compounds in soybean seed from either test site, indicating that early and later season applications of glyphosate have no effects on phytoestrogen levels in glyphosate-resistant soybeans. Glyphosate and AMPA residues were higher in seeds from treatment 3 than from the other two treatments in which glyphosate was used earlier. Intermediate levels were found in treatments 1 and 2. Low levels of glyphosate and AMPA were found in treatment 4 and a hand-weeded control, apparently due to herbicide drift.

Duke SO; Rimando AM; Pace PF; Reddy KN; Smeda RJ

2003-01-01

59

GLYPHOSATE AND GLYPHOSATE-RESISTANT CROP INTERACTIONS WITH RHIZOSPHERE MICROORGANISMS  

Science.gov (United States)

Glyphosate and glyphosate-resistant crops represent a major advancement in effective weed management that is now widely used in many crop production systems. Studies conducted during 1997-2007 showed that Fusarium root colonization was consistently higher on Roundup Ready (RR) soybean treated with g...

60

Reduced insulin sensitivity as a marker for acute mountain sickness?  

Science.gov (United States)

Abstract Spliethoff, Kerstin, Daniela Meier, Isabelle Aeberli, Max Gassmann, Wolfgang Langhans, Marco Maggiorini, Thomas A. Lutz, and Oliver Goetze. Reduced insulin sensitivity as a marker for acute mountain sickness? High Alt Med Biol 14:240-250, 2013-Reduced insulin sensitivity might increase the susceptibility to acute mountain sickness (AMS). The diabetogenic side effects of dexamethasone should therefore be considered for AMS treatment. To examine whether reduced insulin sensitivity is predictive of AMS and how it is affected by dexamethasone at high altitude, we analyzed endocrine and metabolic parameters obtained from healthy mountaineers in Zurich (LA; 490?m), and 2 and 4 days after fast ascent to the Capanna Regina Margherita (HA2, HA4; 4559?m). 14 of 25 participants developed AMS and were treated with dexamethasone starting in the evening of HA2. Before and after ingestion of an 1800?kJ meal, plasma was analyzed for erythropoietin (EPO) and cholecystokinin (CCK). Insulin sensitivity (HOMA-S) and beta cell activity were calculated. HOMA-S (pEPO levels (pEPO levels were more susceptible to AMS. Reduced CCK may contribute to the beneficial effect of dexamethasone on high altitude anorexia. However, reduced insulin sensitivity questions the widespread use of dexamethasone to prevent/treat AMS. PMID:24067185

Spliethoff, Kerstin; Meier, Daniela; Aeberli, Isabelle; Gassmann, Max; Langhans, Wolfgang; Maggiorini, Marco; Lutz, Thomas A; Goetze, Oliver

2013-09-01

 
 
 
 
61

76 FR 27268 - Glyphosate; Pesticide Tolerance  

Science.gov (United States)

...residues of both glyphosate and its metabolite N-acetyl glyphosate. N-acetyl glyphosate is found in genetically modified (GMO) glyphosate-resistant commodities, including corn, grown in the U.S. Therefore, it is included in the U.S....

2011-05-11

62

Impact of the invasive mussel Limnoperna fortunei on glyphosate concentration in water.  

UK PubMed Central (United Kingdom)

The use of glyphosate has increased dramatically during the past years around the world. Microbial communities are altered when glyphosate reaches water bodies. The freshwater golden mussel Limnoperna fortunei is an invasive species that has rapidly dispersed since it was introduced in Argentina two decades ago. Mussels alter aquatic conditions through their filtrating activity by increasing water clarity and nutrient recycling. We aim to evaluate the potential capacity of the golden mussel to reduce glyphosate concentration in water, in laboratory conditions. Firstly, the evasive response of mussels to glyphosate (10, 20, and 40 mg l?¹) was evaluated and a toxicity test was carried out for these concentrations. A three-week experiment was then performed to assess glyphosate variation under mussel presence for two mussel sizes. Finally, mussels' role on glyphosate concentration was evaluated considering different mussel parts (living organisms and empty shells) through another three-week experiment. Laboratory experiments were performed in triplicate using 2-l microcosms. An initial glyphosate concentration between 16 and 19 mg l?¹ was used, and when mussels or valvae were added, 20 organisms per aquaria were used. Samples were obtained at days 0, 1, 2, 4, 8, 14, and 21. Glyphosate decreased by 40% under large mussel presence in both experiments, and was reduced by 25% in empty shell treatments. We believe that part of the herbicide that disappears from the water column is adsorbed in valvae surface, while another proportion is being mineralized by microbial communities in shells' biofilm. The mechanisms by which living mussels increase glyphosate dissipation would be degradation, possibly mediated by bacteria associated to mussel's metabolism. Glyphosate half-life depended on mussel and valvae presence and varied with mussel size. L. fortunei presence (either alive or as empty valvae) alters glyphosate concentration in water. We provide preliminary observations from laboratory experiments, with strong potential ecological consequences, about two stressors that could be acting jointly on the environment.

Di Fiori E; Pizarro H; dos Santos Afonso M; Cataldo D

2012-07-01

63

Changes in constructed Brassica communities treated with glyphosate drift.  

UK PubMed Central (United Kingdom)

We constructed a mixed-species community designed to simulate roadside and field edge plant communities and exposed it to glyphosate drift in order to test three hypotheses: (1) higher fitness in transgenic Brassica carrying the CP4 EPSPS transgene that confers resistance to glyphosate will result in significant changes in the plant community relative to control communities; (2) given repeated years of glyphosate drift selective pressure, the increased fitness of the transgenic Brassica with CP4 EPSPS will contribute to an increase in the proportion of transgenic progeny produced in plant communities; and (3) the increased fitness of Brassica carrying the CP4 EPSPS transgene will contribute to decreased levels of mycorrhizal infection and biomass in a host species (Trifolium incarnatum). Due to regulatory constraints that prevented the use of outdoor plots for our studies, in 2005 we established multispecies communities in five large cylindrical outdoor sunlit mesocosms (plastic greenhouses) designed for pollen confinement. Three of the community members were sexually compatible Brassica spp.: transgenic glyphosate-resistant canola (B. napus) cultivar (cv.) RaideRR, glyphosate-sensitive non-transgenic B. napus cv. Sponsor, and a weedy B. rapa (GRIN Accession 21735). Additional plant community members were the broadly distributed annual weeds Digitaria sanguinalis, Panicum capillare, and Lapsana communis. Once annually in 2006 and 2007, two mesocosms were sprayed with glyphosate at 10% of the field application rate to simulate glyphosate drift as a selective pressure. After two years, changes were observed in community composition, plant density, and biomass in both control and treatment mesocosms. In control mesocosms, the weed D. sanguinalis (crabgrass) began to dominate. In glyphosate drift-treated mesocosms, Brassica remained the dominant genus and the incidence of the CP4 EPSPS transgene increased in the community. Shoot biomass and mycorrhizal infection in Trifolium incarnatum planted in 2008 were significantly lower in mesocosms that had received glyphosate drift treatments. Our results suggest that, over time, glyphosate drift can contribute to persistence of Brassica that express the CP4 EPSPS transgene and that increased representation of Brassica (a non-mycorrhizal host) within plant communities may indirectly negatively impact beneficial ecosystem services associated with arbuscular mycorrhiza.

Watrud LS; King G; Londo JP; Colasanti R; Smith BM; Waschmann RS; Lee EH

2011-03-01

64

A Preliminary Study of Soybean Genotype Responses to Glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of four application rates of glyphosate (Roundup, 360 g a.i./l) – 180; 360; 720 and 1440 g a.i./ha on the survival, dynamics of growth, and accumulation of fresh biomass in g per plant was studied on eight newly-developed Bulgarian lines, varieties and candidate varieties of soybean bred by different methods under greenhouse conditions. The objective of this study was to determine and compare the sensitivities of different soybean genotypes to glyphosate. The studied soybean genotypes showed different levelsof glyphosate sensitivity due to their genetic differences. Glyphosate rates of 180, 360, 720 and 1440 g a.i./ha, applied at the stage of three trifoliate leaves (V4) of soybean had effect on the survival of the studied genotypes and can be presented conditionally in the following order: H (40.6%) < G (40.7%) < D (51.3%) < C (52.6%) < F (58.9%) < E (60.5%) < B (62.0%) < A (65.3%). The depression coefficients (B) of the studied characteristics dependedmainly on soybean genotypes and the applied herbicide rates. The tested glyphosate rates showed a high (GI 26.5-51.6%) to relatively low degree of toxicity (GI 16.0-18.7%) in the studied soybean genotypes.

Plamen Marinov-Serafimov

2009-01-01

65

Glyphosate-Degrading Microorganisms from Industrial Activated Sludge  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A plating medium was developed to isolate N-phosphonomethylglycine (glyphosate)-degrading microorganisms, with glyphosate as the sole phosphorus source. Two industrial biosystems treating glyphosate wastes contained elevated microbial counts on the medium. One purified isolate metabolized glyphosate...

Balthazor, Terry M.; Hallas, Laurence E.

66

Reduced insulin sensitivity as a marker for acute mountain sickness?  

UK PubMed Central (United Kingdom)

Abstract Spliethoff, Kerstin, Daniela Meier, Isabelle Aeberli, Max Gassmann, Wolfgang Langhans, Marco Maggiorini, Thomas A. Lutz, and Oliver Goetze. Reduced insulin sensitivity as a marker for acute mountain sickness? High Alt Med Biol 14:240-250, 2013-Reduced insulin sensitivity might increase the susceptibility to acute mountain sickness (AMS). The diabetogenic side effects of dexamethasone should therefore be considered for AMS treatment. To examine whether reduced insulin sensitivity is predictive of AMS and how it is affected by dexamethasone at high altitude, we analyzed endocrine and metabolic parameters obtained from healthy mountaineers in Zurich (LA; 490?m), and 2 and 4 days after fast ascent to the Capanna Regina Margherita (HA2, HA4; 4559?m). 14 of 25 participants developed AMS and were treated with dexamethasone starting in the evening of HA2. Before and after ingestion of an 1800?kJ meal, plasma was analyzed for erythropoietin (EPO) and cholecystokinin (CCK). Insulin sensitivity (HOMA-S) and beta cell activity were calculated. HOMA-S (p<0.01) and EPO levels (p<0.05) were lower in Zurich in the group developing AMS and given dexamethasone, i.e., before treatment and exposure to hypoxia. CCK was lower (p<0.01) and glucose and insulin were higher on HA4 in the dexamethasone group compared to the untreated group. Individuals with low baseline insulin sensitivity and low baseline EPO levels were more susceptible to AMS. Reduced CCK may contribute to the beneficial effect of dexamethasone on high altitude anorexia. However, reduced insulin sensitivity questions the widespread use of dexamethasone to prevent/treat AMS.

Spliethoff K; Meier D; Aeberli I; Gassmann M; Langhans W; Maggiorini M; Lutz TA; Goetze O

2013-09-01

67

Isoflavone, Glyphosate and Aminomethylphosphonic Acid Levels in Seeds of Glyphosate-treated, Glyphosate-resistant Soybean  

Science.gov (United States)

The estrogenic isoflavones of soybeans and their glycosides are products of the shikimate pathway, the target pathway of glyphosate. We tested the hypothesis that non-phytotoxic levels of glyphosate and other herbicides known to affect phenolic compound biosynthesis might influence levels of these ...

68

Controle de plantas daninhas na cultura de soja resistente ao glyphosate/ Weed control in glyphosate tolerant soybean crop  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O objetivo da pesquisa foi avaliar o controle de plantas daninhas em área cultivada com soja resistente ao herbicida glyphosate, sem a utilização de práticas complementares de manejo de plantas daninhas. Foram desenvolvidos experimentos, em condições de campo, nos anos agrícolas 2005/2006 e 2006/2007 em Jaboticabal (SP). Foram avaliadas duas cultivares de soja resistentes ao glyphosate (CD 214 RR e M-SOY 8008 RR), oito tratamentos de herbicidas (glyphosate, em apli (more) cação única, nas doses de 0,48; 0,72; 0,96 e 1,20 kg ha-1 de equivalente ácido, associadas ou não a aplicação sequencial na dose de 0,48 kg ha-1), além de duas testemunhas, uma capinada e outra mantida infestada. As cultivares de soja influenciaram na infestação das espécies de plantas daninhas na área. Sem a aplicação de glyphosate, houve o predomínio de X. strumarium na área, desfavorecendo a ocorrência de outras espécies. Quando utilizado glyphosate, independentemente da dose, a infestação contabilizada aos 35 e 40 dias após a primeira aplicação, no primeiro e segundo ano, respectivamente, foi baixa. O controle de plantas daninhas na cultura da soja transgênica é diretamente influenciado pela dose de glyphosate, havendo controle satisfatório com a aplicação única de 0,96 kg ha-1 ou a sequencial de 0,48 + 0,48 kg ha-1 de glyphosate. Em situação de menor infestação (2006/2007), a aplicação única de 0,48 kg ha-1 de glyphosate é suficiente para o controle das plantas daninhas. As cultivares de soja transgênica CD 214 RR e M-SOY 8008 RR influenciam diferencialmente a dinâmica das espécies de plantas daninhas, sendo o controle químico mais efetivo na situação de cultivo de M-SOY 8008 RR, em que houve menor diversidade e desenvolvimento das plantas daninhas. Abstract in english This work evaluated the weed control in glyphosate tolerant soybean crop without additional management practices. Two experiments were carried out under field conditions in the agricultural years 2006/2007 and 2007/2008 in Jaboticabal, São Paulo State, Brazil. It was tested two glyphosate-tolerant varieties (CD 214 RR and M-SOY 8008 RR), eight herbicide treatments (Roundup Ready, single spraying at rates of 0.48; 0.72; 0.96 and 1.20 kg ha-1 of glyphosate acid equivalent, (more) associates or not to sequential spraying at 0.48 kg ha-1), and two controls (one under mechanical control and one untreated control). Soybean varieties influenced the infestation of weed species. Xanthium strumarium was predominant in control treatments, reducing the occurrence of other weeds species. Independently of the dose, glyphosate sprayings resulted in low infestations 35 and 40 days after the first spraying, in the first and second year, respectively. The weed control in transgenic soybean is directly influenced for the glyphosate rate, having satisfactory control with the single application at 0.96 kg ha-1 or sequential at 0.48 plus 0.48 kg ha-1 of glyphosate. Under lesser infestation conditions (2006/2007), the single application at 0.48 kg ha-1 of glyphosate is enough for weed control. The varieties of transgenic soybean CD 214 RR and M-SOY 8008 RR distinguishing influence the dynamics of the weed species. The chemical control is more effective in the M-SOY 8008 RR, where it had minor diversity and development of the weed.

Correia, Núbia Maria; Durigan, Julio Cezar

2010-01-01

69

Controle de plantas daninhas na cultura de soja resistente ao glyphosate Weed control in glyphosate tolerant soybean crop  

Directory of Open Access Journals (Sweden)

Full Text Available O objetivo da pesquisa foi avaliar o controle de plantas daninhas em área cultivada com soja resistente ao herbicida glyphosate, sem a utilização de práticas complementares de manejo de plantas daninhas. Foram desenvolvidos experimentos, em condições de campo, nos anos agrícolas 2005/2006 e 2006/2007 em Jaboticabal (SP). Foram avaliadas duas cultivares de soja resistentes ao glyphosate (CD 214 RR e M-SOY 8008 RR), oito tratamentos de herbicidas (glyphosate, em aplicação única, nas doses de 0,48; 0,72; 0,96 e 1,20 kg ha-1 de equivalente ácido, associadas ou não a aplicação sequencial na dose de 0,48 kg ha-1), além de duas testemunhas, uma capinada e outra mantida infestada. As cultivares de soja influenciaram na infestação das espécies de plantas daninhas na área. Sem a aplicação de glyphosate, houve o predomínio de X. strumarium na área, desfavorecendo a ocorrência de outras espécies. Quando utilizado glyphosate, independentemente da dose, a infestação contabilizada aos 35 e 40 dias após a primeira aplicação, no primeiro e segundo ano, respectivamente, foi baixa. O controle de plantas daninhas na cultura da soja transgênica é diretamente influenciado pela dose de glyphosate, havendo controle satisfatório com a aplicação única de 0,96 kg ha-1 ou a sequencial de 0,48 + 0,48 kg ha-1 de glyphosate. Em situação de menor infestação (2006/2007), a aplicação única de 0,48 kg ha-1 de glyphosate é suficiente para o controle das plantas daninhas. As cultivares de soja transgênica CD 214 RR e M-SOY 8008 RR influenciam diferencialmente a dinâmica das espécies de plantas daninhas, sendo o controle químico mais efetivo na situação de cultivo de M-SOY 8008 RR, em que houve menor diversidade e desenvolvimento das plantas daninhas.This work evaluated the weed control in glyphosate tolerant soybean crop without additional management practices. Two experiments were carried out under field conditions in the agricultural years 2006/2007 and 2007/2008 in Jaboticabal, São Paulo State, Brazil. It was tested two glyphosate-tolerant varieties (CD 214 RR and M-SOY 8008 RR), eight herbicide treatments (Roundup Ready, single spraying at rates of 0.48; 0.72; 0.96 and 1.20 kg ha-1 of glyphosate acid equivalent, associates or not to sequential spraying at 0.48 kg ha-1), and two controls (one under mechanical control and one untreated control). Soybean varieties influenced the infestation of weed species. Xanthium strumarium was predominant in control treatments, reducing the occurrence of other weeds species. Independently of the dose, glyphosate sprayings resulted in low infestations 35 and 40 days after the first spraying, in the first and second year, respectively. The weed control in transgenic soybean is directly influenced for the glyphosate rate, having satisfactory control with the single application at 0.96 kg ha-1 or sequential at 0.48 plus 0.48 kg ha-1 of glyphosate. Under lesser infestation conditions (2006/2007), the single application at 0.48 kg ha-1 of glyphosate is enough for weed control. The varieties of transgenic soybean CD 214 RR and M-SOY 8008 RR distinguishing influence the dynamics of the weed species. The chemical control is more effective in the M-SOY 8008 RR, where it had minor diversity and development of the weed.

Núbia Maria Correia; Julio Cezar Durigan

2010-01-01

70

Selection and characterization of glyphosate tolerance in birdsfoot trefoil (Lotus corniculatus)  

Energy Technology Data Exchange (ETDEWEB)

If birdsfoot trefoil (Lotus corniculatus L.) was tolerant to glyphosate (N-(phosphonomethyl)glycine), Canada thistle (Cirsium arvense (L.) Scop.) and other dicot weeds could be selectively controlled in certified seed production fields. Glyphosate tolerance in birdsfoot trefoil was identified in plants from the cultivar Leo, plants regenerated from tolerant callus, and selfed progeny of plants regenerated from callus. Plants from the three sources were evaluated in field studies for tolerance to glyphosate at rates up to 1.6 kg ae/ha. Plants of Leo selected for tolerance exhibited a twofold range in the rate required to reduce shoot weight 50% (I{sub 50}s from 0.6 to 1.2 kg/ha glyphosate). Plants regenerated from tolerant callus had tolerance up to 66% greater than plants regenerated from unselected callus. Transgressive segregation for glyphosate tolerance was observed in the selfed progeny of two regenerated plants that both had I{sub 50}s of 0.7 kg/ha glyphosate. The selfed progeny ranged from highly tolerant (I{sub 50} of 1.5 kg/ha) to susceptible (I{sub 50} of 0.5 kg/ha). Spray retention, {sup 14}C-glyphosate absorption and translocation did not account for the differential tolerance of nine plants that were evaluated from the three sources. The specific activity of 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase ranged from 1.3 to 3.5 nmol/min{sm bullet}mg among the nine plants and was positively correlated with glyphosate tolerance. Leo birdsfoot trefoil was found to have significant variation in glyphosate tolerance which made it possible to initiate a recurrent selection program to select for glyphosate tolerance in birdsfoot trefoil. Two cycles of selection for glyphosate tolerance were practiced in three birdsfoot trefoil populations, Leo, Norcen, and MU-81.

Boerboom, C.M.

1989-01-01

71

Selection and characterization of glyphosate tolerance in birdsfoot trefoil (Lotus corniculatus)  

International Nuclear Information System (INIS)

If birdsfoot trefoil (Lotus corniculatus L.) was tolerant to glyphosate [N-(phosphonomethyl)glycine], Canada thistle [Cirsium arvense (L.) Scop.] and other dicot weeds could be selectively controlled in certified seed production fields. Glyphosate tolerance in birdsfoot trefoil was identified in plants from the cultivar Leo, plants regenerated from tolerant callus, and selfed progeny of plants regenerated from callus. Plants from the three sources were evaluated in field studies for tolerance to glyphosate at rates up to 1.6 kg ae/ha. Plants of Leo selected for tolerance exhibited a twofold range in the rate required to reduce shoot weight 50% (I50s from 0.6 to 1.2 kg/ha glyphosate). Plants regenerated from tolerant callus had tolerance up to 66% greater than plants regenerated from unselected callus. Transgressive segregation for glyphosate tolerance was observed in the selfed progeny of two regenerated plants that both had I50s of 0.7 kg/ha glyphosate. The selfed progeny ranged from highly tolerant (I50 of 1.5 kg/ha) to susceptible (I50 of 0.5 kg/ha). Spray retention, 14C-glyphosate absorption and translocation did not account for the differential tolerance of nine plants that were evaluated from the three sources. The specific activity of 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase ranged from 1.3 to 3.5 nmol/min sm-bullet mg among the nine plants and was positively correlated with glyphosate tolerance. Leo birdsfoot trefoil was found to have significant variation in glyphosate tolerance which made it possible to initiate a recurrent selection program to select for glyphosate tolerance in birdsfoot trefoil. Two cycles of selection for glyphosate tolerance were practiced in three birdsfoot trefoil populations, Leo, Norcen, and MU-81.

1989-01-01

72

Glyphosate inhibition of 5-enolpyruvylshikimate 3-phosphate synthease from suspension-cultured cells of Nicotiana silvestris  

Energy Technology Data Exchange (ETDEWEB)

Treatment of isogenic suspension-cultured cells of Nicotiana silvestris Speg, et Comes with glyphosate (N-(phosphonomethyl)glycine) led to elevated levels of intracellular shikimate (364-fold increase by 1.0 millimolar glyphosate). In the presence of glyphosate, it is likely that most molecules of shikimate originate from the action of 3-deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthase-Mn since this isozyme, in contrast to the DAHP synthase-Co isozyme, is insensitive to inhibition by glyphosate. 5-Enolpyruvylshikimate 3-phosphate (EPSP) synthase (EC 2.5.1.19) from N. silvestris was sensitive to micromolar concentrations of glyphosate and possessed a single inhibitor binding site. Rigorous kinetic studies of EPSP synthase required resolution from the multiple phosphatase activities present in crude extracts, a result achieved by ion-exchange column chromatography. Although EPSP synthase exhibited a broad pH profile (50% of maximal activity between pH 6.2 and 8.5), sensitivity to glyphosate increased dramatically with increasing pH within this range. In accordance with these data and the pK/sub a/ values of glyphosate, it is likely that the ionic form of glyphosate inhibiting EPSP synthase is COO/sup -/CH/sub 2/NH/sub 2//sup +/CH/sub 2/PO/sub 3//sup 2 -/, and that a completely ionized phosphono group is essential for inhibition. At pH 7.0, inhibition was competitive with respect to phosphoenolpyruvate (K/sub i/ = 1.25 micromolar) and uncompetitive with respect to shikimate-3-P (K/sub i/ = 18.3 micromolar). All data were consistent with a mechanism of inhibition in which glyphosate competes with PEP for binding to an (enzyme:shikimate-3-P) complex and ultimately forms the dead-end complex of (enzyme:shikimate-3-P:glyphosate). 36 references, 8 figures, 1 table.

Rubin, J.L.; Gaines, C.G.; Jensen, R.A.

1984-07-01

73

Lens design with reduced sensitivity to thermally induced stress birefringence.  

UK PubMed Central (United Kingdom)

In optical systems required to maintain the polarization states of the transiting light, mechanically induced stress birefringence can degrade performance, at least locally altering polarization phase and ultimately reducing polarization contrast. Although thermally induced stress birefringence can cause similar problems in imaging systems bearing high optical flux, appropriate design approaches to resolve this problem have been lacking. This paper first develops criteria to select optical glasses with reduced sensitivity to thermally induced stress birefringence. The design of projection lenses using the resulting thermal stress desensitized reduced glass list is then discussed, as is the application of such lenses in laser projection systems.

Kurtz AF; Bietry JR

2013-06-01

74

Reducing risk for ventilator associated pneumonia through nursing sensitive interventions.  

Science.gov (United States)

The purpose of this paper is to describe an improvement initiative designed to implement nurse sensitive interventions known to reduce patients' risk for ventilator associated pneumonia (VAP), in cardiothoracic intensive care patients. This initiative is a part of one Australian critical care unit's efforts to identify and measure compliance with key nursing interventions known to improve cardiac surgical patients' outcomes. The premise behind the initiative is that improved nursing process and surveillance systems allow emerging trends to catalyse action and motivate nurses to reduce patients' risk for infection acquisition. At five and nine months following implementation of the initiative a>70% compliance rate in 11 out of the 15 nurse sensitive interventions known to reduce patients' risks for VAP and a drop in VAP incidence from 13.4% to 7.69% from per 1000 ventilator days was accomplished. PMID:23816403

Micik, Svatka; Besic, Nihada; Johnson, Natalie; Han, Matilda; Hamlyn, Stephen; Ball, Hayley

2013-06-29

75

Effects of watering frequency, shade and glyphosate application on Paspalum conjugatum Berg (sour grass).  

UK PubMed Central (United Kingdom)

Greenhouse experiments were conducted to determine effects of shade, water and a combination of either watering frequency or shade and glyphosate on growth of Paspalum conjugatum Berg. (sour grass). Plant height, shoot and root dry weight and numbers of leaves and tillers decreased as light and water levels decreased. The combined effect of glyphosate application and reduced watering frequency influenced shoot and root growth of plants receiving daily watering. Glyphosate had less effect on shoot and root dry weight and injury ratings of sour grass grown under water stress. Reduction in the growth of sour grass treated with 0.2 kg/ha glyphosate was greater under shade (52% and 69%) than under exposed conditions (0% and 36% shade). Visible injury to sour grass with 0.05 kg/ha glyphosate was greater under 69% shade than under exposed conditions.

Sahid IB; Ibrahim RB; Kadri S

1996-02-01

76

Effect of glyphosate and fungicide combinations on weed control in soybeans  

UK PubMed Central (United Kingdom)

Field studies were conducted in 2005 and 2006 along the upper Texas Gulf Coast near Yoakum, Texas and in 2005 near Tifton, Georgia to determine weed control and soybean response to glyphosate plus fungicide tank-mixes. In Texas, glyphosate at 0.77kg a.e./ha in combination with azoxystrobin, tebuconazole, pyraclostrobin, and tetraconazole applied at the V3 or R1 soybean growth stage controlled Amaranthus palmeri and Panicum texanum at least 97% control while glyphosate alone controlled both weeds 100%. In Georgia, glyphosate applied alone to a mixed stand of annual grasses [P. texanum L., Digitaria ciliaris (Retz.) Koel., and Dactyloctenium aegyptium (L.) Willd.] at the V3 stage of soybean development provided only 68% control and at the R1 stage provided 94% control. When rated approximately four weeks after treatment application, increased control of the mixed stand of annual grasses was obtained with glyphosate plus azoxystrobin or pyraclostrobin applied at the R1 stage rather than the V3 growth stage. No yield results were obtained at the Georgia location; however, at the Texas location, soybean yields were higher when glyphosate plus azoxystrobin or tetraconazole was applied at V3 compared with the R1 stage. In conclusion, tank mixing of glyphosate with a fungicide is a good option and can be used to reduce production costs. If glyphosate applications are delayed too long, yield reductions can occur due to early season weed competition.

Grichar WJames; Prostko EricP

2009-07-01

77

Adição simultânea de sulfato de amônio e ureia à calda de pulverização do herbicida glyphosate Simultaneous addition of ammonium sulfate and urea to glyphosate spray solution  

Directory of Open Access Journals (Sweden)

Full Text Available Dois experimentos foram desenvolvidos em casa de vegetação, com o objetivo de avaliar a eficácia do herbicida glyphosate sobre plantas de Digitaria insularis quando soluções de ureia (U; 5 g L-1), sulfato de amônio (SA; 15 g L-1) ou U+SA (2,5 + 7,5 g L-1) foram utilizadas como veículo de pulverização. Aos 28 dias após aplicação, de acordo com as curvas de dose-resposta (primeiro experimento), foram necessários 409 g ha-1 de glyphosate para atingir 50% de controle da planta daninha (C50) quando água sem adjuvantes foi usada como veículo de pulverização. Para obtenção dos mesmos 50% de controle, as doses de glyphosate foram reduzidas para 373, 208 e 189 g ha-1; quando o herbicida foi pulverizado utilizando solução de U, SA ou U+SA, respectivamente. A redução na dose oriunda da combinação de glyphosate e U+SA também foi observada para controles de 80% (C80). No segundo experimento, a adição de U+SA à calda elevou o controle obtido com a menor dose de glyphosate (360 g ha-1), igualando-o à aplicação da maior dose (720 g ha-1) sem adjuvantes. Esses resultados evidenciam efeito complementar de U e SA em elevar a eficácia do glyphosate para controle de D. insularis.Two trials were carried out under greenhouse conditions to evaluate the efficacy of glyphosate on Digitaria insularis plants when urea (U; 5 g L-1); ammonium sulfate (AMS; 15 g L-1) or U+AMS (2.5 + 7.5 g L-1) were used as spray solutions. At 28 days after application, according to dose-response curves (first trial), 409 g ha-1 of glyphosate application were necessary to obtain 50% of weed control (C50) when water without adjuvants was used as spray solution. To reach the same 50% of weed control, glyphosate rates were reduced to 373, 208 and 189 g ha-1, when the herbicide was sprayed using a solution of U, AMS or U+AMS, respectively. Reduction in the dose of glyphosate combined with U+AMS was also observed for controls of 80% (C80). In the second trial, the addition of U+SA to glyphosate spray solution increased the control obtained at the lowest glyphosate rate (360 g ha-1), leveling it to the highest rate application (720 g ha-1) without adjuvants. These results show the complementary action of U and AMS to increase glyphosate efficacy to control D. insularis.

S.J.P. Carvalho; A.C.R. Dias; G.M. Shiomi; P.J. Christoffoleti

2010-01-01

78

Adição simultânea de sulfato de amônio e ureia à calda de pulverização do herbicida glyphosate/ Simultaneous addition of ammonium sulfate and urea to glyphosate spray solution  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Dois experimentos foram desenvolvidos em casa de vegetação, com o objetivo de avaliar a eficácia do herbicida glyphosate sobre plantas de Digitaria insularis quando soluções de ureia (U; 5 g L-1), sulfato de amônio (SA; 15 g L-1) ou U+SA (2,5 + 7,5 g L-1) foram utilizadas como veículo de pulverização. Aos 28 dias após aplicação, de acordo com as curvas de dose-resposta (primeiro experimento), foram necessários 409 g ha-1 de glyphosate para atingir 50% de cont (more) role da planta daninha (C50) quando água sem adjuvantes foi usada como veículo de pulverização. Para obtenção dos mesmos 50% de controle, as doses de glyphosate foram reduzidas para 373, 208 e 189 g ha-1; quando o herbicida foi pulverizado utilizando solução de U, SA ou U+SA, respectivamente. A redução na dose oriunda da combinação de glyphosate e U+SA também foi observada para controles de 80% (C80). No segundo experimento, a adição de U+SA à calda elevou o controle obtido com a menor dose de glyphosate (360 g ha-1), igualando-o à aplicação da maior dose (720 g ha-1) sem adjuvantes. Esses resultados evidenciam efeito complementar de U e SA em elevar a eficácia do glyphosate para controle de D. insularis. Abstract in english Two trials were carried out under greenhouse conditions to evaluate the efficacy of glyphosate on Digitaria insularis plants when urea (U; 5 g L-1); ammonium sulfate (AMS; 15 g L-1) or U+AMS (2.5 + 7.5 g L-1) were used as spray solutions. At 28 days after application, according to dose-response curves (first trial), 409 g ha-1 of glyphosate application were necessary to obtain 50% of weed control (C50) when water without adjuvants was used as spray solution. To reach the (more) same 50% of weed control, glyphosate rates were reduced to 373, 208 and 189 g ha-1, when the herbicide was sprayed using a solution of U, AMS or U+AMS, respectively. Reduction in the dose of glyphosate combined with U+AMS was also observed for controls of 80% (C80). In the second trial, the addition of U+SA to glyphosate spray solution increased the control obtained at the lowest glyphosate rate (360 g ha-1), leveling it to the highest rate application (720 g ha-1) without adjuvants. These results show the complementary action of U and AMS to increase glyphosate efficacy to control D. insularis.

Carvalho, S.J.P.; Dias, A.C.R.; Shiomi, G.M.; Christoffoleti, P.J.

2010-01-01

79

Economic and herbicide use impacts of glyphosate-resistant crops.  

UK PubMed Central (United Kingdom)

More than 95% of United States maize, cotton, soybean and sugarbeet acres are treated with herbicides for weed control. These products are used to improve the economic profitability of crop production for farmers. Since their introduction in 1996, over 75 million acres of genetically engineered glyphosate-resistant crops have been planted, making up 80% of soybean acres and 70% of cotton acres in the USA. These genetically engineered crops have been adopted by farmers because they are perceived to offer greater economic benefits than conventional crop and herbicide programs. The adoption of glyphosate-resistant crops has saved US farmers 1.2 billion dollars associated with the costs of conventional herbicide purchases, application, tillage and hand weeding. With the adoption of glyphosate-resistant sugarbeets on currently planted sugarbeet acres, US growers could potentially save an additional 93 million dollars. The adoption of glyphosate-resistant crops by US agriculture has reduced herbicide use by 37.5 million lbs, although the adoption of glyphosate-resistant sugarbeets would dampen this reduction by 1 million lbs.

Gianessi LP

2005-03-01

80

Economic and herbicide use impacts of glyphosate-resistant crops.  

Science.gov (United States)

More than 95% of United States maize, cotton, soybean and sugarbeet acres are treated with herbicides for weed control. These products are used to improve the economic profitability of crop production for farmers. Since their introduction in 1996, over 75 million acres of genetically engineered glyphosate-resistant crops have been planted, making up 80% of soybean acres and 70% of cotton acres in the USA. These genetically engineered crops have been adopted by farmers because they are perceived to offer greater economic benefits than conventional crop and herbicide programs. The adoption of glyphosate-resistant crops has saved US farmers 1.2 billion dollars associated with the costs of conventional herbicide purchases, application, tillage and hand weeding. With the adoption of glyphosate-resistant sugarbeets on currently planted sugarbeet acres, US growers could potentially save an additional 93 million dollars. The adoption of glyphosate-resistant crops by US agriculture has reduced herbicide use by 37.5 million lbs, although the adoption of glyphosate-resistant sugarbeets would dampen this reduction by 1 million lbs. PMID:15706602

Gianessi, Leonard P

2005-03-01

 
 
 
 
81

Questions concerning the potential impact of glyphosate-based herbicides on amphibians.  

Science.gov (United States)

Use of glyphosate-based herbicides is increasing worldwide. The authors review the available data related to potential impacts of these herbicides on amphibians and conduct a qualitative meta-analysis. Because little is known about environmental concentrations of glyphosate in amphibian habitats and virtually nothing is known about environmental concentrations of the substances added to the herbicide formulations that mainly contribute to adverse effects, glyphosate levels can only be seen as approximations for contamination with glyphosate-based herbicides. The impact on amphibians depends on the herbicide formulation, with different sensitivity of taxa and life stages. Effects on development of larvae apparently are the most sensitive endpoints to study. As with other contaminants, costressors mainly increase adverse effects. If and how glyphosate-based herbicides and other pesticides contribute to amphibian decline is not answerable yet due to missing data on how natural populations are affected. Amphibian risk assessment can only be conducted case-specifically, with consideration of the particular herbicide formulation. The authors recommend better monitoring of both amphibian populations and contamination of habitats with glyphosate-based herbicides, not just glyphosate, and suggest including amphibians in standardized test batteries to study at least dermal administration. PMID:23637092

Wagner, Norman; Reichenbecher, Wolfram; Teichmann, Hanka; Tappeser, Beatrix; Lötters, Stefan

2013-08-01

82

Questions concerning the potential impact of glyphosate-based herbicides on amphibians.  

UK PubMed Central (United Kingdom)

Use of glyphosate-based herbicides is increasing worldwide. The authors review the available data related to potential impacts of these herbicides on amphibians and conduct a qualitative meta-analysis. Because little is known about environmental concentrations of glyphosate in amphibian habitats and virtually nothing is known about environmental concentrations of the substances added to the herbicide formulations that mainly contribute to adverse effects, glyphosate levels can only be seen as approximations for contamination with glyphosate-based herbicides. The impact on amphibians depends on the herbicide formulation, with different sensitivity of taxa and life stages. Effects on development of larvae apparently are the most sensitive endpoints to study. As with other contaminants, costressors mainly increase adverse effects. If and how glyphosate-based herbicides and other pesticides contribute to amphibian decline is not answerable yet due to missing data on how natural populations are affected. Amphibian risk assessment can only be conducted case-specifically, with consideration of the particular herbicide formulation. The authors recommend better monitoring of both amphibian populations and contamination of habitats with glyphosate-based herbicides, not just glyphosate, and suggest including amphibians in standardized test batteries to study at least dermal administration.

Wagner N; Reichenbecher W; Teichmann H; Tappeser B; Lötters S

2013-08-01

83

Yield of glyphosate-resistant sugar beets and efficiency of weed management systems with glyphosate and conventional herbicides under German and Polish crop production.  

Science.gov (United States)

In sugar beet production, weed control is one of the most important and most expensive practices to ensure yield. Since glyphosate-resistant sugar beets are not yet approved for cultivation in the EU, little commercial experience exists with these sugar beets in Europe. Experimental field trials were conducted at five environments (Germany, Poland, 2010, 2011) to compare the effects of glyphosate with the effects of conventional weed control programs on the development of weeds, weed control efficiency and yield. The results show that the glyphosate weed control programs compared to the conventional methods decreased not only the number of herbicide applications but equally in magnitude decreased the dosage of active ingredients. The results also showed effective weed control with glyphosate when the weed covering was greater and sugar beets had a later growth stage of four true leaves. Glyphosate-resistant sugar beets applied with the glyphosate herbicide two or three times had an increase in white sugar yield from 4 to 18 % in comparison to the high dosage conventional herbicide systems. In summary, under glyphosate management sugar beets can positively contribute to the increasingly demanding requirements regarding efficient sugar beet cultivation and to the demands by society and politics to reduce the use of chemical plant protection products in the environment. PMID:23271374

Nichterlein, Henrike; Matzk, Anja; Kordas, Leszek; Kraus, Josef; Stibbe, Carsten

2012-12-28

84

Yield of glyphosate-resistant sugar beets and efficiency of weed management systems with glyphosate and conventional herbicides under German and Polish crop production.  

UK PubMed Central (United Kingdom)

In sugar beet production, weed control is one of the most important and most expensive practices to ensure yield. Since glyphosate-resistant sugar beets are not yet approved for cultivation in the EU, little commercial experience exists with these sugar beets in Europe. Experimental field trials were conducted at five environments (Germany, Poland, 2010, 2011) to compare the effects of glyphosate with the effects of conventional weed control programs on the development of weeds, weed control efficiency and yield. The results show that the glyphosate weed control programs compared to the conventional methods decreased not only the number of herbicide applications but equally in magnitude decreased the dosage of active ingredients. The results also showed effective weed control with glyphosate when the weed covering was greater and sugar beets had a later growth stage of four true leaves. Glyphosate-resistant sugar beets applied with the glyphosate herbicide two or three times had an increase in white sugar yield from 4 to 18 % in comparison to the high dosage conventional herbicide systems. In summary, under glyphosate management sugar beets can positively contribute to the increasingly demanding requirements regarding efficient sugar beet cultivation and to the demands by society and politics to reduce the use of chemical plant protection products in the environment.

Nichterlein H; Matzk A; Kordas L; Kraus J; Stibbe C

2013-08-01

85

Glyphosate inhibits rust diseases in glyphosate-resistant wheat and soybean  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Glyphosate is a broad-spectrum herbicide used for the control of weeds in glyphosate-resistant crops. Glyphosate inhibits 5-enolpyruvyl shikimate 3-phosphate synthase, a key enzyme in the synthesis of aromatic amino acids in plants, fungi, and bacteria. Studies with glyphosate-resistant wheat have s...

Feng, Paul C. C.; Baley, G. James; Clinton, William P.; Bunkers, Greg J.; Alibhai, Murtaza F.; Paulitz, Timothy C.

86

Herança da resistência de azevém (Lolium multiflorum) ao glyphosate/ Inheritance of azevém (Lolium multiflorum) resistance to glyphosate  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O glyphosate é o principal produto usado para manejo não-seletivo das plantas daninhas. Já foram identificados biótipos de azevém resistentes a esse herbicida no Rio Grande do Sul, os quais estão se tornando predominantes rapidamente. Objetivou-se neste trabalho identificar o tipo de herança, o número de genes que conferem resistência e o grau de resistência dos biótipos homozigotos e heterozigotos resistentes em azevém. Foram realizados cruzamentos recíproco (more) s entre genitores suscetíveis e resistentes para obtenção de sementes F1 e, em seguida, efetuaram-se os retrocruzamentos resistente e sensível. Plantas F1 foram cruzadas, para obtenção da geração F2. Sobre as plantas F1, F2, RCr e RCs e genitores foi aplicado o glyphosate na dose de 720 g ha-1, para avaliar a segregação. A fim de avaliar o grau de resistência, as plantas F1 e os genitores resistente e sensível foram tratados com doses crescentes de glyphosate (0, 360, 720, 1.440 e 2.880 g ha-1). As plantas F1 evidenciaram resposta intermediária ao biótipo resistente e sensível, demonstrando que a interação alélica é do tipo dominância incompleta. As plantas F2 mostraram tendência para segregação 3:1, indicando que a característica resistência ao glyphosate é controlada por um gene semidominante. Abstract in english Glyphosate is a non-selective herbicide used to control weeds. Azevem plants, which are tolerant to glyphosate, have been identified in Rio Grande do Sul, where they are rapidly becoming predominant. The objective of this work was to identify inheritance type, number of genes conferring resistance, and the degree of resistance in azevem plants. Reciprocal crossings between sensitive and resistant plants have been carried out to obtain F1 seeds which were crossed among the (more) mselves to obtain F2 plants .Herbicide containing 720 g ha-1 was applied on the F1, F2, RCr, Rc and parent plants to estimate segregation. To evaluate the degree of resistance of the F1 plants, resistant and sensitive parents were sprayed with increasing rates of glyphosate (0, 360, 720, 1.440 and 2.880 g ha-1). F1 plants showed intermediate response to the resistant and sensitive biotypes, indicating that allelic interaction is of the incomplete dominance type. F2 plants showed a tendency for segregation 3:1, indicating that resistance to glyphosate is controlled by a semi-dominant gene.

Vargas, L.; Moraes, R.M.A.; Berto, C.M.

2007-09-01

87

Herança da resistência de azevém (Lolium multiflorum) ao glyphosate Inheritance of azevém (Lolium multiflorum) resistance to glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available O glyphosate é o principal produto usado para manejo não-seletivo das plantas daninhas. Já foram identificados biótipos de azevém resistentes a esse herbicida no Rio Grande do Sul, os quais estão se tornando predominantes rapidamente. Objetivou-se neste trabalho identificar o tipo de herança, o número de genes que conferem resistência e o grau de resistência dos biótipos homozigotos e heterozigotos resistentes em azevém. Foram realizados cruzamentos recíprocos entre genitores suscetíveis e resistentes para obtenção de sementes F1 e, em seguida, efetuaram-se os retrocruzamentos resistente e sensível. Plantas F1 foram cruzadas, para obtenção da geração F2. Sobre as plantas F1, F2, RCr e RCs e genitores foi aplicado o glyphosate na dose de 720 g ha-1, para avaliar a segregação. A fim de avaliar o grau de resistência, as plantas F1 e os genitores resistente e sensível foram tratados com doses crescentes de glyphosate (0, 360, 720, 1.440 e 2.880 g ha-1). As plantas F1 evidenciaram resposta intermediária ao biótipo resistente e sensível, demonstrando que a interação alélica é do tipo dominância incompleta. As plantas F2 mostraram tendência para segregação 3:1, indicando que a característica resistência ao glyphosate é controlada por um gene semidominante.Glyphosate is a non-selective herbicide used to control weeds. Azevem plants, which are tolerant to glyphosate, have been identified in Rio Grande do Sul, where they are rapidly becoming predominant. The objective of this work was to identify inheritance type, number of genes conferring resistance, and the degree of resistance in azevem plants. Reciprocal crossings between sensitive and resistant plants have been carried out to obtain F1 seeds which were crossed among themselves to obtain F2 plants .Herbicide containing 720 g ha-1 was applied on the F1, F2, RCr, Rc and parent plants to estimate segregation. To evaluate the degree of resistance of the F1 plants, resistant and sensitive parents were sprayed with increasing rates of glyphosate (0, 360, 720, 1.440 and 2.880 g ha-1). F1 plants showed intermediate response to the resistant and sensitive biotypes, indicating that allelic interaction is of the incomplete dominance type. F2 plants showed a tendency for segregation 3:1, indicating that resistance to glyphosate is controlled by a semi-dominant gene.

L. Vargas; R.M.A. Moraes; C.M. Berto

2007-01-01

88

Reduced Insulin Sensitivity in Adults with Pseudohypoparathyroidism Type 1a.  

UK PubMed Central (United Kingdom)

Context:Disruption of the Gs?maternal allele leads to severe obesity and insulin resistance in mice and early-onset obesity in patients with pseudohypoparathyroidism (PHP) type 1a. However, insulin resistance and glucose metabolism have not been systematically characterized in patients with PHP1a.Objective, Design, and Setting:In a cross-sectional, case-control study, we examined insulin sensitivity, ?-cell function, energy expenditure, and sympathetic nervous system activity (SNA) in adults with PHP1a.Study Participants:PHP1a patients (n=8) and healthy control subjects (n=24) matched for age (41 ± 7 vs. 41 ± 7 yr [mean ± SD]), gender, and percent body fat.Methods:Insulin sensitivity (SI), acute insulin response to glucose, and disposition index (DI) were assessed during an FSIVGTT. Oral glucose insulin sensitivity (OGIS) was measured during a mixed meal. Energy expenditure was measured using whole room indirect calorimetry. Body composition was assessed via dual-energy x-ray absorptiometry and SNA by measuring 24-hr urinary catecholamine concentrations.Results:Results: PHP1a patients were less insulin-sensitive than their matched controls based upon SI and OGIS. Non-diabetic PHP1a patients tended to have a lower SI (p = 0.09) and reduced OGIS (p = 0.03). DI, a composite measure of ?-cell function also tended to be lower in patients (p=0.07). Total caloric intake, resting energy expenditure (REE), total EE, meal-induced thermogenesis, and 24-hr urinary catecholamine concentrations were not significantly different between the groups.Conclusions:Adults with PHP-1a have reduced insulin sensitivity compared with their matched controls that may contribute to the pathogenesis of glucose intolerance and diabetes in these patients.

Muniyappa R; Warren MA; Zhao X; Aney SC; Courville AB; Chen KY; Brychta RJ; Germain-Lee EL; Weinstein LS; Skarulis MC

2013-09-01

89

Micromorfologia foliar na análise da fitotoxidez por glyphosate em Eucalyptus grandis/ Leaf micromorphology in the analysis of glyphosate toxicity in Eucalyptus grandis  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Foram avaliados os efeitos da deriva de formulações comerciais de glyphosate sobre a superfície foliar e o crescimento de clones de eucalipto. Mudas de seis clones foram submetidas a 129,6 g ha-1 de glyphosate das formulações comerciais Scout®, Roundup NA®, Roundup transorb® e Zapp QI®. Entre os clones não foram identificadas diferenças quanto à tolerância ao glyphosate. Plantas expostas à deriva simulada de Roundup transorb® e Zapp QI® apresentaram, respe (more) ctivamente, a maior e menor porcentagem de intoxicação. Observou-se menor massa seca em plantas expostas ao glyphosate, independentemente da formulação, e menor altura naquelas expostas ao Scout® e ao Roundup transorb®. As características quantitativas da superfície foliar não foram afetadas pelo glyphosate. As alterações micromorfológicas ocorreram na ausência de danos visíveis e foram observadas em ambas as faces da epiderme, em todos os clones avaliados. Danos como erosão e aspecto amorfo das ceras epicuticulares e infestação por hifas fúngicas ocorreram, independentemente da formulação utilizada. A avaliação anatômica da superfície foliar foi relevante para descrição e interpretação dos danos causados pelo glyphosate. Os dados de crescimento e de intoxicação indicam o Zapp QI® como a formulação de menor risco para a cultura do eucalipto quanto aos efeitos indesejáveis da deriva. Abstract in english The effects of commercial glyphosate drift on the leaf surface and growth of eucalypt clones were evaluated. Seedlings of six clones were submitted to 129.6 g ha-1 sub-rate of commercial glyphosate formulations Scout®, Roundup NA®, Roundup transorb® and Zapp QI®. No differences in tolerance to glyphosate were observed among the clones. Plants exposed to simulated drift of Roundup transorb® and Zapp QI® presented the highest and lowest intoxication percentages, respe (more) ctively. Plants exposed to glyphosate reduced dry biomass, regardless of the formulation, and also reduced height of the plants exposed to Scout® and Roundup transorb®. Leaf surface characteristics were not affected by glyphosate application. However, the micromorphological damages occurred prior to the appearance of visible symptoms, and were observed on both faces of the epidermis, in all clones tested. Damages such as erosion and amorphous aspect of epicuticular waxes and infestation of fungal hyphae occurred, independently of the formulation used. The anatomical evaluation of the leaf surface effectively described the damages caused by glyphosate. The growth and intoxication data indicate Zapp QI® formulation as presenting the lowest risk to eucalypt culture, in relation to the undesirable herbicide drift effects.

Tuffi Santos, L.D.; Sant'Anna-Santos, B.F.; Meira, R.M.S.A.; Ferreira, F.A.; Tiburcio, R.A.S.T.; Silva, E.C.F.

2009-01-01

90

Photosynthetic activity of coffee after application of glyphosate subdoses/ Atividade fotossintética do cafeeiro após aplicação de subdoses de glyphosate  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Para o controle de plantas daninhas em lavouras cafeeiras, os produtores utilizam herbicidas não-seletivos, como o glyphosate, empregado em aplicações dirigidas. Apesar de todos os cuidados com a aplicação, são constatados casos de intoxicação em plantas, sendo de fundamental importância o conhecimento dos efeitos sobre os processos fotossintéticos. Objetivou-se com este trabalho avaliar as características associadas à atividade fotossintética entre cultivare (more) s de cafeeiro submetidos a doses de glyphosate. O experimento foi conduzido em casa de vegetação utilizando-se três cultivares de cafeeiro (Coffea arabica): Acaiá (MG-6851), Catucaí Amarelo (2 SL) e Topázio (MG-1190) e, três subdoses do glyphosate (0,0; 115,2 e 460,8 g ha-1), em esquema fatorial 3 x 3. Em função da aplicação do herbicida observou-se redução de carbono interno, razão carbono interno e do ambiente, consumo de carbono e taxa fotossintética, aos 15 DAA na quarta folha. Na mesma folha aos 45 DAA, constatou-se menor consumo de carbono pelos cultivares. Na última folha apesar de inferiores concentrações de carbono, não obteve-se diferença no consumo e taxa fotossintética. O glyphosate resulta em danos metabólicos com efeitos transitórios sobre a atividade fotossintética, sendo o cultivar Acaiá o mais tolerante. Este efeito transitório pode resultar em danos prolongados e irreversíveis no crescimento da cultura. Abstract in english Farmers use non-selective herbicides, such as glyphosate, in directed applications to control weeds in coffee crops. Despite the precautions used during the application of herbicides, there are usually reports of poisoning in plantation areas. Moreover, it is fundamental to understand the effects of glyphosate on photosynthetic processes. The present study aimed to evaluate the characteristics associated with the photosynthetic activity in coffee cultivars subjected to do (more) ses of glyphosate. The experiment was conducted in a greenhouse using three varieties of coffee (Coffea arabica), including Acaiá (MG-6851), Catucaí Amarelo (2 SL) and Topázio (MG-1190), and three subdoses of glyphosate (0.0, 115.2 and 460.8 g ha-1) in a 3 x 3 factorial scheme. Herbicide application led to reduced internal carbon, ratio between internal and environmental carbon, carbon consumption and photosynthetic rate at 15 days after application (DAA) in the fourth leaf. In the same leaf at 45 DAA, the carbon consumption of the cultivars was even less. Despite low carbon concentrations, no difference in consumption and photosynthetic rate was observed in the last leaf. Glyphosate caused metabolic damage with transitory effects on the photosynthetic rate; the Acaiá cultivar was the most tolerant. These transitory effects may result in irreversible and prolonged damage to crop growth.

Carvalho, Felipe Paolinelli de; França, André Cabral; Lemos, Vinícius Teixeira; Ferreira, Evander Alves; Santos, José Barbosa dos; Silva, Antonio Alberto da

2013-03-01

91

Resistência de azevém (Lolium multiflorum) ao herbicida glyphosate Resistance of italian ryegrass (Lolium multiflorum) to glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available O azevém é uma gramínea de ciclo anual, constituindo-se com freqüência em planta infestante em lavouras de trigo do Rio Grande do Sul. Em experimentos realizados em casa de vegetação e no campo, foi avaliada a suscetibilidade de dois biótipos de azevém ao herbicida glyphosate, bem como a eficiência de herbicidas de ação total na dessecação de Lolium multiflorum para a semeadura direta de trigo. O delineamento experimental foi completamente casualizado em casa de vegetação e de blocos ao acaso em campo, com três e quatro repetições, respectivamente. Foram avaliados herbicidas com mecanismos de ação distintos em diferentes doses: glyphosate, glufosinate, clethodim, haloxyfop-r e diclofop, paraquat e paraquat + diuron. Os resultados, em casa de vegetação, evidenciam que o biótipo sensível é totalmente controlado com glyphosate na dose de 360 g e.a. ha-1 e que doses de até 1.440 g e.a. ha-1 não afetam significativamente o acúmulo de matéria seca do biótipo resistente e produzem toxicidade inferior a 15% sobre este. Já as doses entre 1.440 e 5.760 g e.a. ha-1 de glyphosate reduzem significativamente a produção de matéria seca e resultam em toxicidade inferior a 45%. Em campo, os melhores controles de azevém foram propiciados pelos tratamentos clethodim (79,2 g ha-1) e diuron + paraquat (300 + 600 g ha-1), que não diferiram entre si. Assim, evidencia-se que a população de Lolium multiflorum avaliada neste trabalho é constituída predominantemente de um biótipo resistente aos herbicidas inibidores da enzima EPSPs.Italian ryegrass (Lolium multiflorum) is cultivated as forage and/or cover crop in no-till system. However, it is also a serious weed in wheat and other winter cereals in Southern Brazil. Experiments were conducted at greenhouse and field conditions to evaluate the susceptibility of two ryegrass biotype to glyphosate as well as the efficacy of other herbicides on the post-emergence control of the species for sowing wheat under no-till system. The experimental design was a completely randomized design for the greenhouse experiment and a completely randomized block design for the field experiment. Herbicides with different mechanisms of action were evaluated on the weed control: glyphosate, glufosinate, clethodim, haloxyfop-r and diclofop, paraquat and paraquat+diuron. The results obtained under greenhouse conditions indicated the glyphosate susceptible biotype was controlled by the rate of 360 g e.a. ha-1. The resistant ryegrass biotype had no reduction in dry matter production and less than 15 % phytotoxicity caused by glyphosate up to 1,440 g e.a. ha-1. However, glyphosate rates between 1440 and 5,760 g e.a. ha-1 reduced dry matter accumulation and resulted in toxicities under45%. Under field conditions, the best Lolium multiflorum control was given by clethodim 79.2 g ha-1 and diuron + paraquat at 300+600 g ha¹, respectively. The results obtained in these studies indicated that the population was composed predominantly by a biotype resistant to EPSPs inhibitor herbicides.

E.S. Roman; L. Vargas; M.A. Rizzardi; R.W. Mattei

2004-01-01

92

THE REMOVAL OF GLYPHOSATE FROM DRINKING WATER  

Science.gov (United States)

The effectiveness of granulated activated carbon (GAC), packed activated carbon (PAC), conventional treatment, membranes, and oxidation for removing glyphosate from natural waters is evaluated. Results indicate that GAC and PAC are not effective in removing glyphosate, while oxid...

93

75 FR 24969 - Glyphosate From China  

Science.gov (United States)

...COMMISSION [Investigation No. 731-TA-1178 (Preliminary)] Glyphosate From China AGENCY: United States International Trade Commission...gives notice that its antidumping investigation concerning glyphosate from China (investigation No. 731-TA-1178...

2010-05-06

94

75 FR 17768 - Glyphosate From China  

Science.gov (United States)

...COMMISSION [Investigation No. 731-TA-1178 (Preliminary)] Glyphosate From China AGENCY: United States International Trade Commission...is materially retarded, by reason of imports from China of glyphosate, provided for in subheadings 2931.00.90 and...

2010-04-07

95

Selectivity of glyphosate tank mixtures for RR soybean Seletividade de glyphosate em misturas em tanque para soja RR  

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Full Text Available An active ingredients mixture of different action mechanisms is an essential tool to prevent or manage areas with resistant weeds. However, it is important that such a mixture provides adequate selectivity to the crop. The aim of this work was to evaluate glyphosate selectivity to glyphosate-resistant (RR) soybean, and also verify if there is selectivity in mixtures with other active ingredients applied postemergence aimed at new control strategies, which might be used in RR soybean cultivation. The herbicides and respective rates (g ha-1) evaluated were: glyphosate (720, 960, 1,200, and 1,440), and the mixtures of glyphosate (960) with cloransulam-methyl (30.24), fomesafen (125), lactofen (72), chlorimuron-ethyl (12.5), flumiclorac-pentyl (30), bentazon (480), or imazethapyr (80). All treatments were applied in postemergence when the soybean crop was at V2 to V3 stage. Treatments with glyphosate or in mixtures with postemergent herbicides showed visual effects of phytotoxicity when applied to the glyphosate-resistant soybean. Effects such as reduction in plant height, crop closure, number of pods per plant, and hundred grain weight could be observed. However, the effects related to plant development were mostly transient and did not persist during the crop cycle. Among the studied treatments, only the mixture of glyphosate and lactofen was not selective to the crop, promoting negative effects on most characteristics analyzed and consequently reducing grain yield.A mistura de ingredientes ativos de diferentes mecanismos de ação é uma ferramenta essencial para prevenir ou manejar áreas com plantas daninhas resistentes. No entanto é importante que tais associações forneçam adequada seletividade para a cultura. O objetivo deste trabalho foi avaliar a seletividade do glyphosate a soja RR, e verificar também, se existe seletividade a misturas com outros ingredientes ativos, aplicados em pós-emergência, visando novas estratégias de controle que poderão ser empregadas no cultivo da soja RR. Os herbicidas e respectivas doses (g ha-1) avaliadas foram: glyphosate isolado (720, 960, 1.200 e 1.440) e as misturas de glyphosate (960) com cloransulam-methyl (30,24), fomesafen (125), lactofen (72), chlorimuron-ethyl (12,5), flumiclorac-pentyl (30), bentazon (480) e imazethapyr (80). Todos os tratamentos foram aplicados em dose única em pós-emergência quando a soja estava no estádio V2 a V3. Tratamentos com glyphosate isolado ou em mistura com herbicidas pós-emergentes aplicados em dose única promoveram efeitos visuais de fitointoxicação quando aplicados na soja resistente ao glyphosate. Efeitos como redução na altura das plantas, no fechamento da cultura, no número de vagens por planta e na massa de cem grãos puderam ser observados. Entretanto, os efeitos relatados ao desenvolvimento das plantas foram na sua maioria transientes, não persistindo durante todo ciclo da cultura. Dentre os tratamentos estudados, somente a mistura entre glyphosate e lactofen não apresentou seletividade à cultura, promovendo efeitos negativos na maioria das características estudadas e consequentemente reduzindo a produtividade de grãos.

D.G Alonso; J Constantin; R.S Oliveira Jr; J.G.Z Arantes; S.D Cavalieri; G Santos; F.A Rios; L.H.M Franchini

2011-01-01

96

Control of glyphosate resistant giant ragweed in soybean with preplant herbicides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Giant ragweed was the first glyphosate resistant weed identified in Canada. It is a very competetive weed in row crop production and has been found to drastically reduce yields of soybean; therefore, control of this competitive weed is essential....

Joanna Follings; Nader Soltani; Darren E. Robinson; François J. Tardif; Mark B. Lawton; Peter H. Sikkema

97

Confidence intervals for sensitivity indices using reduced-basis metamodels  

CERN Document Server

Global sensitivity analysis is often impracticable for complex and time demanding numerical models, as it requires a large number of runs. The reduced-basis approach provides a way to replace the original model by a much faster to run code. In this paper, we are interested in the information loss induced by the approximation on the estimation of sensitivity indices. We present a method to provide a robust error assessment, hence enabling significant time savings without sacrifice on precision and rigourousness. We illustrate our method with an experiment where computation time is divided by a factor of nearly 6. We also give directions on tuning some of the parameters used in our estimation algorithms.

Janon, Alexandre; Prieur, Clémentine

2011-01-01

98

NEW PREPARATION METHOD OF GLYPHOSATE BY OXIDATION PMIDA WITH AIR  

UK PubMed Central (United Kingdom)

The invention provides a new preparation method of glyphosate by oxidation of PMIDA, which uses air or oxygen as oxidant and the combination of activated carbon or carbon nanotube with supersonic wave as catalyst. The advantages of the method comprise high yield, high selectivity, high purity of the product, cheap catalyst, low cost, no reducer and no hydrogen peroxide.

GUO YULAI; YIN YINGWU; TIAN JINPING; YAN HUIJUAN

99

SPRAY DROPLET COMPARISONS FOR GLYPHOSATE FORMULATIONS  

Science.gov (United States)

Preliminary studies were conducted to evaluate the effects of three glyphosate formulations on spray droplet size. A Malvern laser droplet analyzer was used to determine spray droplet size for three glyphosate formulations; Roundup Original®, UltraMax®, and WeatherMax®. Each glyphosate formulation...

100

78 FR 60707 - Glyphosate; Pesticide Tolerances  

Science.gov (United States)

...EPA-HQ-OPP-2011-0307; FRL-9396-6] Glyphosate; Pesticide Tolerances AGENCY: Environmental...tolerance for residues of the herbicide glyphosate in or on canola, seed at 20 parts per...expression from the combined residues of glyphosate only, to the combined residues of...

2013-10-02

 
 
 
 
101

Resposta de diferentes populações de Digitaria insularis ao herbicida glyphosate Response of different Digitaria insularis populations to glyphosate  

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Full Text Available Objetivou-se com estse trabalho avaliar o controle químico de diferentes populações de capim-amargoso (Digitaria insularis) pelo herbicida glyphosate por meio de curva de dose-resposta, além de propor tratamentos alternativos para as populações mais tolerantes. O delineamento experimental foi o de blocos ao acaso, com quatro repetições, em esquema fatorial 5 x 9. As sementes de capim-amargoso foram coletadas em cinco locais: área de produção de grãos da Fazenda de Ensino, Pesquisa e Produção da UNESP, Jaboticabal (SP); área de produção comercial de grãos, localizada nos municípios de Campo Florido-MG e Rio Verde-GO; pomar de laranja, localizado no município de Matão (SP); e área não agrícola sem histórico da aplicação de glyphosate (Jaboticabal-SP). O glyphosate (0D, 1/4D, 1/2D, D, 2D, 4D e 8D, em que D é a dose recomendada de 1,5 kg ha-1 de equivalente ácido) e as suas associações [glyphosate + fluazifop-p-butil (1,5 + 0,25 kg ha-1) e glyphosate (1,5 kg ha-1) com sequencial de diuron + paraquat (0,20 + 0,40 kg ha-1 + 0,2% de surfatante)] foram pulverizados em plantas de sete a oito perfilhos e altura média de 20 cm. As populações de capim-amargoso de Campo Florido e Rio Verde foram consideradas suscetíveis; as de Jaboticabal e Matão, tolerantes; e a da área não agrícola, de sensibilidade intermediária. A associação de glyphosate ao fluazifop ou a sua aplicação com sequencial de diuron + paraquat foram eficazes no controle das populações mais tolerantes de capim-amargoso.The objective of this study was to evaluate the chemical control of different sourgrass (Digitaria insularis) populations by the herbicide glyphosate through dose-response curves, besides considering alternative treatments to control tolerant populations. A randomized block design was used with four replications, in a factorial scheme (5 x 9). Sourgrass seeds were colleted from five locations: a grain production area located at the educational, research and production farm of UNESP, Jaboticabal-SP; a grain production area located in the agricultural area of Campo Florido, MG, and Rio Verde, GO; citrus production area located in the agricultural area of Matão, SP, and an area without previous glyphosate application (Jaboticabal-SP). Glyphosate (0D, 1/4D, 1/2D, D, 2D, 4D and 8D, where D is the recommended rate of 1.5 kg ha-1 of acid equivalent) and its associations [glyphosate plus fluazifop-p-butyl (1.5 plus 0.25 kg ha-1) and glyphosate (1.5 kg ha-1) in sequence with diuron plus paraquat (0.20 plus 0.40 kg ha-1 plus 0.2% of surfactant)] were sprayed on the 7-8 tiller plants with average height of 20 cm. Campo Florido, MG and Rio Verde, GO sourgrass populations were considered susceptible; those of Jaboticabal-SP and Matão,SP were found to be tolerant and those from the nonagricultural area were considered of intermediate sensitivity. The association of glyphosate with fluazifop, or its application in sequence with diuron plus paraquat, were efficient in the control of sourgrass tolerant populations.

N.M Correia; G.J Leite; L.D Garcia

2010-01-01

102

Resposta de diferentes populações de Digitaria insularis ao herbicida glyphosate/ Response of different Digitaria insularis populations to glyphosate  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Objetivou-se com estse trabalho avaliar o controle químico de diferentes populações de capim-amargoso (Digitaria insularis) pelo herbicida glyphosate por meio de curva de dose-resposta, além de propor tratamentos alternativos para as populações mais tolerantes. O delineamento experimental foi o de blocos ao acaso, com quatro repetições, em esquema fatorial 5 x 9. As sementes de capim-amargoso foram coletadas em cinco locais: área de produção de grãos da Fazend (more) a de Ensino, Pesquisa e Produção da UNESP, Jaboticabal (SP); área de produção comercial de grãos, localizada nos municípios de Campo Florido-MG e Rio Verde-GO; pomar de laranja, localizado no município de Matão (SP); e área não agrícola sem histórico da aplicação de glyphosate (Jaboticabal-SP). O glyphosate (0D, 1/4D, 1/2D, D, 2D, 4D e 8D, em que D é a dose recomendada de 1,5 kg ha-1 de equivalente ácido) e as suas associações [glyphosate + fluazifop-p-butil (1,5 + 0,25 kg ha-1) e glyphosate (1,5 kg ha-1) com sequencial de diuron + paraquat (0,20 + 0,40 kg ha-1 + 0,2% de surfatante)] foram pulverizados em plantas de sete a oito perfilhos e altura média de 20 cm. As populações de capim-amargoso de Campo Florido e Rio Verde foram consideradas suscetíveis; as de Jaboticabal e Matão, tolerantes; e a da área não agrícola, de sensibilidade intermediária. A associação de glyphosate ao fluazifop ou a sua aplicação com sequencial de diuron + paraquat foram eficazes no controle das populações mais tolerantes de capim-amargoso. Abstract in english The objective of this study was to evaluate the chemical control of different sourgrass (Digitaria insularis) populations by the herbicide glyphosate through dose-response curves, besides considering alternative treatments to control tolerant populations. A randomized block design was used with four replications, in a factorial scheme (5 x 9). Sourgrass seeds were colleted from five locations: a grain production area located at the educational, research and production far (more) m of UNESP, Jaboticabal-SP; a grain production area located in the agricultural area of Campo Florido, MG, and Rio Verde, GO; citrus production area located in the agricultural area of Matão, SP, and an area without previous glyphosate application (Jaboticabal-SP). Glyphosate (0D, 1/4D, 1/2D, D, 2D, 4D and 8D, where D is the recommended rate of 1.5 kg ha-1 of acid equivalent) and its associations [glyphosate plus fluazifop-p-butyl (1.5 plus 0.25 kg ha-1) and glyphosate (1.5 kg ha-1) in sequence with diuron plus paraquat (0.20 plus 0.40 kg ha-1 plus 0.2% of surfactant)] were sprayed on the 7-8 tiller plants with average height of 20 cm. Campo Florido, MG and Rio Verde, GO sourgrass populations were considered susceptible; those of Jaboticabal-SP and Matão,SP were found to be tolerant and those from the nonagricultural area were considered of intermediate sensitivity. The association of glyphosate with fluazifop, or its application in sequence with diuron plus paraquat, were efficient in the control of sourgrass tolerant populations.

Correia, N.M; Leite, G.J; Garcia, L.D

2010-12-01

103

Crescimento de cultivares de café arábica submetidos a doses do glyphosate/ Growth of arabica coffee cultivars submitted to glyphosate doses  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Avaliaram-se, neste trabalho, os efeitos do glyphosate sobre o crescimento de três cultivares de café arábica. Utilizou-se o esquema fatorial (3 x 5) em delineamento de blocos casualizados, com quatro repetições, sendo os tratamentos compostos por três cultivares de café: Catucaí Amarelo (2 SL), Oeiras (MG-6851) e Topázio (MG-1190) e cinco doses de glyphosate (0; 57,6; 115,2; 230,4; e 460,8 g ha-1). O herbicida foi aplicado quando as plantas de café se apresenta (more) vam com 21 pares de folhas e de forma que não atingisse o terço superior delas. Aos 45 e 120 dias após a aplicação do glyphosate (DAA), avaliaram-se os incrementos na altura, na área foliar, no diâmetro do caule, no número de folhas e nos ramos plagiotrópicos, sendo eles mensurados inicialmente no dia da aplicação do herbicida; aos 10, 45 e 120 DAA, avaliou-se a porcentagem de intoxicação das plantas. A massa da matéria seca de folhas, raízes e caule, a densidade e o comprimento radicular foram avaliados aos 120 DAA. Os sintomas de intoxicação das plantas de café causados pelo glyphosate foram semelhantes nos diferentes cultivares, sendo caracterizados por clorose e estreitamento do limbo foliar. Os incrementos no número de folhas e ramos plagiotrópicos e no diâmetro do caule, independentemente do cultivar, não foram alterados pelo glyphosate. O cultivar Topázio foi o mais sensível ao glyphosate quanto a acúmulo de área foliar, de massa de matéria seca e densidade radicular. Abstract in english This study evaluated the effects of glyphosate on the growth of three arabica coffee cultivars. A factorial (3 x 5) was arranged in a randomized block design with four replications, with treatments consisting of three coffee varieties: Catucaí Amarelo (2 SL), Oeiras (MG-6851) and Topázio (MG-1190) and five glyphosate doses (0, 57.6, 115.2, 230.4 and 460.8 g ha-1 ). The herbicide was applied when the coffee plants reached 21 pairs of leaves, before reaching their upper t (more) hird ones. At 45 and 120 days after glyphosate application (DAA), increase in leaf area, stem diameter, number of leaves and plagiotropic branches was evaluated, being initially measured on the day the herbicide was applied, and plant intoxication rate at 10, 45 and 120 DAA. Dry matter of leaves, roots and stem, and root length and density were measured at 120 DAA. Symptoms of coffee plant intoxication caused by glyphosate were similar in different cultivars, being characterized by chlorosis and leaf narrowing. Increase in the number of leaves, plagiotropic branches and stem diameter, regardless of the cultivar, was not affected by glyphosate. Cultivar Topázio was the most sensitive to glyphosate, in terms of accumulation of leaf area, root dry matter and root density.

França, A.C.; Freitas, M.A.M.; Fialho, C.M.T.; Silva, A.A.; Reis, M.R.; Galon, L.; Victoria Filho, R.

2010-01-01

104

Qualidade fisiológica de sementes de soja colhidas em duas épocas após dessecação com glyphosate/ Physiological quality of soybean seeds harvested at two periods after glyphosate desiccation  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A dessecação de plantas de soja em pré-colheita com glyphosate vem se tornando prática rotineira entre os produtores, apesar de não ser recomendada, pois pode comprometer a qualidade fisiológica das sementes. Objetivou-se avaliar os efeitos da dessecação das plantas em pré-colheita com glyphosate na qualidade fisiológica de sementes de soja colhidas em duas épocas após a aplicação. O delineamento experimental foi em blocos ao acaso, com quatro repetições, (more) em esquema de parcelas subdivididas. As parcelas principais consistiram da dessecação ou não das plantas de soja com glyphosate em pré-colheita, no estádio R7, e as subparcelas da colheita das sementes 7 e 14 dias após a aplicação. As sementes foram avaliadas quanto ao teor de água, dano mecânico, viabilidade, massa de 100 sementes e teor de proteína. A qualidade fisiológica foi avaliada por meio dos testes de germinação, envelhecimento acelerado, condutividade elétrica, comprimento de plântulas e massa da matéria seca das plântulas. A dessecação das plantas de soja em pré-colheita com glyphosate ocasiona redução da germinação das sementes e do desenvolvimento inicial das plântulas. O atraso na colheita reduz a germinação das sementes oriundas de plantas de soja dessecadas com glyphosate em pré-colheita, mas minimiza os efeitos fitotóxicos no desenvolvimento das plântulas. Abstract in english Pre-harvest desiccation of soybean plants with glyphosate has been routinely conducted by seed producers, although it is not recommended because it may reduce seed physiological quality. The objective of this study was to evaluate the effects of the pre-harvest desiccation of plants with glyphosate on the physiological quality of soybean seeds harvested at two different periods after application. The experimental design was completely randomized blocks, with four replicat (more) ions and subdivided plots. Main plots consisted of the presence and absence of a pre-harvest desiccation of soybean plants with glyphosate at the R7 stage, and subplots of seeds harvested 7 and 14 days after application. Moisture content, mechanical damage, viability, weight of 100 seeds, protein content and accumulation of glyphosate residues were determined after harvest. Physiological quality was evaluated by tests for germination, accelerated aging, electrical conductivity, seedling length and seedling dry matter. Pre-harvest desiccation of soybean plants with glyphosate reduces seed germination and seedling development. Delayed harvesting reduces the germination of soybean seeds produced by plants desiccated with glyphosate, but minimizes phytotoxicity in seedling development.

Toledo, Mariana Zampar; Cavariani, Cláudio; França-Neto, José de Barros

2012-01-01

105

Impact of glyphosate on the development, fertility and demography of Chrysoperla externa (Neuroptera: Chrysopidae): ecological approach.  

UK PubMed Central (United Kingdom)

Few ecotoxicological studies have used life table analysis to evaluate the toxicity of pesticides on beneficial organisms. This study is the first report of the effect of the herbicide glyphosate on a predator insect, Chrysoperla externa, using a demographic approach. This predator is associated to soybean pests and has a potential role as a biological control agent in the Neotropical Region. The objective of this work was to evaluate the side-effects of glyphosate on the development, fertility and demography of C. externa, treated orally by ingestion of glyphosate-dipped eggs of Sitotroga cerealella in laboratory conditions. The data were analyzed using the age-stage, two-sex life table. Development from third larval instar to pupae and adult longevity were shorter in glyphosate-treatment than in the control. Adult pre-reproductive period was longer in glyphosate-treatment than in the control. Fecundity and fertility were deeply reduced, as well, being fertility greater affected. A high important reduction was registered in all population parameters. Most eggs from glyphosate-treated cohort looked abnormal, smaller than control, dehydrated and became black 2d after oviposition. In addition, adults developed tumours in the abdomen region at 20d after emergence, being the effect more drastic in females than males. It is beyond the scope of our study to speculate on the effects of this herbicide on C. externa field populations. However, it seems likely that populations under continuous use of glyphosate would be exposed at greater detrimental effects in the long term.

Schneider MI; Sanchez N; Pineda S; Chi H; Ronco A

2009-09-01

106

Heterogeneity reduces sensitivity of cell death for TNF-Stimuli  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Apoptosis is a form of programmed cell death essential for the maintenance of homeostasis and the removal of potentially damaged cells in multicellular organisms. By binding its cognate membrane receptor, TNF receptor type 1 (TNF-R1), the proinflammatory cytokine Tumor Necrosis Factor (TNF) activates pro-apoptotic signaling via caspase activation, but at the same time also stimulates nuclear factor ?B (NF-?B)-mediated survival pathways. Differential dose-response relationships of these two major TNF signaling pathways have been described experimentally and using mathematical modeling. However, the quantitative analysis of the complex interplay between pro- and anti-apoptotic signaling pathways is an open question as it is challenging for several reasons: the overall signaling network is complex, various time scales are present, and cells respond quantitatively and qualitatively in a heterogeneous manner. Results This study analyzes the complex interplay of the crosstalk of TNF-R1 induced pro- and anti-apoptotic signaling pathways based on an experimentally validated mathematical model. The mathematical model describes the temporal responses on both the single cell level as well as the level of a heterogeneous cell population, as observed in the respective quantitative experiments using TNF-R1 stimuli of different strengths and durations. Global sensitivity of the heterogeneous population was quantified by measuring the average gradient of time of death versus each population parameter. This global sensitivity analysis uncovers the concentrations of Caspase-8 and Caspase-3, and their respective inhibitors BAR and XIAP, as key elements for deciding the cell's fate. A simulated knockout of the NF-?B-mediated anti-apoptotic signaling reveals the importance of this pathway for delaying the time of death, reducing the death rate in the case of pulse stimulation and significantly increasing cell-to-cell variability. Conclusions Cell ensemble modeling of a heterogeneous cell population including a global sensitivity analysis presented here allowed us to illuminate the role of the different elements and parameters on apoptotic signaling. The receptors serve to transmit the external stimulus; procaspases and their inhibitors control the switching from life to death, while NF-?B enhances the heterogeneity of the cell population. The global sensitivity analysis of the cell population model further revealed an unexpected impact of heterogeneity, i.e. the reduction of parametric sensitivity.

Schliemann Monica; Bullinger Eric; Borchers Steffen; Allgöwer Frank; Findeisen Rolf; Scheurich Peter

2011-01-01

107

The syndromes of reduced sensitivity to thyroid hormone.  

UK PubMed Central (United Kingdom)

BACKGROUND: Six known steps are required for the circulating thyroid hormone (TH) to exert its action on target tissues. For three of these steps, human mutations and distinct phenotypes have been identified. SCOPE OF REVIEW: The clinical, laboratory, genetic and molecular characteristics of these three defects of TH action are the subject of this review. The first defect, recognized 45years ago, produces resistance to TH and carries the acronym, RTH. In the majority of cases it is caused by TH receptor ? gene mutations. It has been found in over 3000 individuals belonging to approximately 1000 families. Two relatively novel syndromes presenting reduced sensitivity to TH involve membrane transport and metabolism of TH. One of them, caused by mutations in the TH cell-membrane transporter MCT8, produces severe psychomotor defects. It has been identified in more than 170 males from 90 families. A defect of the intracellular metabolism of TH in 10 individuals from 8 families is caused by mutations in the SECISBP2 gene required for the synthesis of selenoproteins, including TH deiodinases. MAJOR CONCLUSIONS: Defects at different steps along the pathway leading to TH action at cellular level can manifest as reduced sensitivity to TH. GENERAL SIGNIFICANCE: Knowledge of the molecular mechanisms involved in TH action allows the recognition of the phenotypes caused by defects of TH action. Once previously known defects have been ruled out, new molecular defects could be sought, thus opening the avenue for novel insights in thyroid physiology. This article is part of a Special Issue entitled Thyroid hormone signaling.

Dumitrescu AM; Refetoff S

2013-07-01

108

Glyphosate-Resistant Giant Ragweed (Ambrosia trifida L.): 2,4-D Dose Response and Control with Postemergence Herbicides in Soybean  

Directory of Open Access Journals (Sweden)

Full Text Available Glyphosate resistant giant ragweed is an increasing problem in glyphosate resistant cropping systems in southwestern Ontario. The postemergence herbicides registered for use in soybean in Ontario do not provide consistent control of glyphosate resistant giant ragweed. There is limited research on the lowest effective rate of 2,4-D for the control of glyphosate resistant giant ragweed. Consequently, the objectives of this study were a) to determine the efficacy of herbicides applied postemergence for the control of glyphosate resistant giant ragweed in glyphosate resistant soybean, and b) to determine the lowest effective rate of 2,4-D for the control of glyphosate-resistant giant ragweed. Ten postemergence herbicide combinations and seven rates of 2,4-D were evaluated in field studies conducted in 2011 and 2012 at six locations confirmed with glyphosate-resistant giant ragweed. The post emergence herbicides evaluated did not provide acceptable/consistent control. Of the herbicides evaluated, glyphosate plus cloransulam-methyl provided 26% to 70% control 8 WAA of glyphosate resistant giant ragweed, which was the best of the herbicides combinations evaluated. The doses of 2,4-D required to reduce giant ragweed shoot dry weight by 50, 80 and 95% were 142, 310 and 1048 g a.e. ha-1, respectively.

Joanna Follings; Nader Soltani; Darren E. Robinson; François J. Tardif; Mark B. Lawton; Peter H. Sikkema

2013-01-01

109

Changes in the accumulation of shikimic acid in mycorrhized Capsicum annuum L. grown with application of glyphosate and phosphorus  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english When glyphosate is added to the soil, it is absorbed by roots and transported by xylem causing growth inhibition in plants. Mycorrhiza is the beneficial association between roots of most plants and soil fungi. The methylphosphonic group of the glyphosate could compete with inorganic phosphates for sorption sites in the soil. The aim of this work was to study the effect of phosphorus availability and glyphosate residues in soil on pepper plant growth, and on physiological (more) parameters, in plants non-inoculated or inoculated with Glomus mosseae or G. intraradices. The phytotoxic effects of the glyphosate were assessed by a bio-indicator as shikimic acid. At high doses, glyphosate (6.32 ?M) reduced root colonization, and this effect was increased by higher levels of phosphorus in the soil. The effects of herbicide on shikimic acid accumulation and on shoot growth began 24 hours after glyphosate treatments (HAT). At 24, 48, and 72 HAT, inoculated plants grown without glyphosate showed higher growth compared to the non-inoculated ones. At high glyphosate (6.32 ?M) and 96 HAT, the growth was completely inhibited. The shikimic acid accumulated in the upper leaves of non-inoculated plants, treated at 3.16 ?M glyphosate, was significantly higher at high P level, related to inoculated ones. These results suggest that the remobilization of glyphosate residues in the soil by the addition of phosphate should be considered a serious problem for crops in treated soils. The mycorrhization increases the pepper plant's tolerance to high glyphosate concentration in the substrate, and may allow support to this stress condition.

Beltrano, José; Ruscitti, Marcela; Arango, Cecilia; Ronco, Marta

2013-01-01

110

Glyphosate catabolism by Pseudomonas sp  

Energy Technology Data Exchange (ETDEWEB)

The pathway for the degradation of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. PG2982 has been determined using metabolic radiolabeling experiments. Radiorespirometry experiments utilizing (3-/sup 14/C) glyphosate revealed that approximately 50-59% of the C3 carbon was oxidized to CO/sub 2/. Fractionation of stationary phase cells labeled with (3-/sup 14/C)glyphosate revealed that from 45-47% of the assimilated C3 carbon is distributed to proteins and that amino acids methionine and serine are highly labeled. The nucleic acid bases adenine and guanine received 90% of the C3 label that was incorporated into nucleic acids, and the only pyrimidine base labeled was thymine. Pulse labeling of PG2982 cells with (3-/sup 14/C)glyphosate revealed that (3-/sup 14/C)sarcosine is an intermediate in glyphosate degradation. Examination of crude extracts prepared from PG2982 cells revealed the presence of an enzyme that oxidizes sarcosine to glycine and formaldehyde. These results indicate that the first step in glyphosate degradation by PG2982 is cleavage of the carbon-phosphorus bond, resulting in the release of sarcosine and a phosphate group. The phosphate group is utilized as a source of phosphorus, and the sarcosine is degraded to glycine and formaldehyde. Phosphonate utilization by Pseudomonas sp. PG2982 was investigated. Each of the ten phosphonates tested were utilized as a sole source of phosphorus by PG2982. Representative compounds tested included alkylphosphonates, 1-amino-substituted alkylphosphonates, amino-terminal phosphonates, and an arylphosphonate. PG2982 cultures degraded phenylphosphonate to benzene and produced methane from methylphosphonate. The data indicate that PG2982 is capable of cleaving the carbon-phosphorus bond of several structurally different phosphonates.

Shinabarger, D.L.

1986-01-01

111

Glyphosate catabolism by Pseudomonas sp  

International Nuclear Information System (INIS)

[en] The pathway for the degradation of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. PG2982 has been determined using metabolic radiolabeling experiments. Radiorespirometry experiments utilizing [3-14C] glyphosate revealed that approximately 50-59% of the C3 carbon was oxidized to CO2. Fractionation of stationary phase cells labeled with [3-14C]glyphosate revealed that from 45-47% of the assimilated C3 carbon is distributed to proteins and that amino acids methionine and serine are highly labeled. The nucleic acid bases adenine and guanine received 90% of the C3 label that was incorporated into nucleic acids, and the only pyrimidine base labeled was thymine. Pulse labeling of PG2982 cells with [3-14C]glyphosate revealed that [3-14C]sarcosine is an intermediate in glyphosate degradation. Examination of crude extracts prepared from PG2982 cells revealed the presence of an enzyme that oxidizes sarcosine to glycine and formaldehyde. These results indicate that the first step in glyphosate degradation by PG2982 is cleavage of the carbon-phosphorus bond, resulting in the release of sarcosine and a phosphate group. The phosphate group is utilized as a source of phosphorus, and the sarcosine is degraded to glycine and formaldehyde. Phosphonate utilization by Pseudomonas sp. PG2982 was investigated. Each of the ten phosphonates tested were utilized as a sole source of phosphorus by PG2982. Representative compounds tested included alkylphosphonates, 1-amino-substituted alkylphosphonates, amino-terminal phosphonates, and an arylphosphonate. PG2982 cultures degraded phenylphosphonate to benzene and produced methane from methylphosphonate. The data indicate that PG2982 is capable of cleaving the carbon-phosphorus bond of several structurally different phosphonates

1986-01-01

112

40 CFR 180.364 - Glyphosate; tolerances for residues.  

Science.gov (United States)

...2009-07-01 2009-07-01 false Glyphosate; tolerances for residues. 180... Specific Tolerances § 180.364 Glyphosate; tolerances for residues. (a...Tolerances are established for residues of glyphosate N -(phosphonomethyl)glycine...

2009-07-01

113

INTERACTIONS OF GLYPHOSATE AND FOLIAR AMENDMENTS WITH IAA SYNTHESIS AND UREASE ACTIVITY BY RHIZOSPHERE BACTERIA OF GLYPHOSATE-RESISTANT SOYBEAN  

Science.gov (United States)

Increased use of glyphosate-resistant crops has raised concerns regarding the potential environmental impacts of glyphosate. Biostimulants (products containing micronutrients, selected microorganisms, and plant growth regulators) and liquid fertilizers applied with glyphosate may affect metabolic ac...

114

The effect of glyphosate on import into a sink leaf of sugar beet  

International Nuclear Information System (INIS)

The basis for glyphosate inducted limitation of carbon import into developing leaves was studied in sugar beet. To separate the effects of the herbicide on export from those on import, glyphosate was supplied to a developing leaf from two exporting source leaves which fed the sink leaf. Carbon import into the sink leaf was determined by supplying 14CO2 to a third source leaf which also supplies carbon to the monitored sink leaf. Import into the sink leaf decreased within 2 to 3 h after glyphosate application, even though photosynthesis and export in the source leaf supplying 14C were unaffected. Reduced import into the sink leaf was accompanied by increased import by the tap root. Elongation of the sink leaf was only slightly decreased following arrival of glyphosate. Photosynthesis by the sink leaf was not inhibited. The results to data support the view that import is slowed by the inhibition of synthesis of structural or storage compounds in the developing leaves.

1990-08-02

115

GLYPHOSATE REMOVAL FROM DRINKING WATER  

Science.gov (United States)

Activated-carbon, oxidation, conventional-treatment, filtration, and membrane studies are conducted to determine which process is best suited to remove the herbicide glyphosate from potable water. Both bench-scale and pilot-scale studies are completed. Computer models are used ...

116

Review of potential environmental impacts of transgenic glyphosate-resistant soybean in Brazil.  

UK PubMed Central (United Kingdom)

Transgenic glyphosate-resistant soybeans (GRS) have been commercialized and grown extensively in the Western Hemisphere, including Brazil. Worldwide, several studies have shown that previous and potential effects of glyphosate on contamination of soil, water, and air are minimal, compared to those caused by the herbicides that they replace when GRS are adopted. In the USA and Argentina, the advent of glyphosate-resistant soybeans resulted in a significant shift to reduced- and no-tillage practices, thereby significantly reducing environmental degradation by agriculture. Similar shifts in tillage practiced with GRS might be expected in Brazil. Transgenes encoding glyphosate resistance in soybeans are highly unlikely to be a risk to wild plant species in Brazil. Soybean is almost completely self-pollinated and is a non-native species in Brazil, without wild relatives, making introgression of transgenes from GRS virtually impossible. Probably the highest agricultural risk in adopting GRS in Brazil is related to weed resistance. Weed species in GRS fields have shifted in Brazil to those that can more successfully withstand glyphosate or to those that avoid the time of its application. These include Chamaesyce hirta (erva-de-Santa-Luzia), Commelina benghalensis (trapoeraba), Spermacoce latifolia (erva-quente), Richardia brasiliensis (poaia-branca), and Ipomoea spp. (corda-de-viola). Four weed species, Conyza bonariensis, Conyza Canadensis (buva), Lolium multiflorum (azevem), and Euphorbia heterophylla (amendoim bravo), have evolved resistance to glyphosate in GRS in Brazil and have great potential to become problems.

Cerdeira AL; Gazziero DL; Duke SO; Matallo MB; Spadotto CA

2007-06-01

117

Growth and Yield of Glyphosate-Resistant Corn under Different Timing of Glyphosate Application  

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A field experiment was conducted in 2002 in Langkat, North Sumatra, to determine the effects of glyphosate application timing on the growth and grain yield of glyphosate-resistant corn. Glyphosate at 1,500 g ha-1 was applied at twelve different treatments namely at the V3 stage, the V...

N. Desmarwansyah; E. Purba

118

Agricultural impacts of glyphosate-resistant soybean cultivation in South America.  

UK PubMed Central (United Kingdom)

In the 2009/2010 growing season, Brazil was the second largest world soybean producer, followed by Argentina. Glyphosate-resistant soybeans (GRS) are being cultivated in most of the soybean area in South America. Overall, the GRS system is beneficial to the environment when compared to conventional soybean. GRS resulted in a significant shift toward no-tillage practices in Brazil and Argentina, but weed resistance may reduce this trend. Probably the highest agricultural risk in adopting GRS in Brazil and South America is related to weed resistance due to use of glyphosate. Weed species in GRS fields have shifted in Brazil to those that can more successfully withstand glyphosate or to those that avoid the time of its application. Five weed species, in order of importance, Conyza bonariensis (L.) Cronquist, Conyza canadensis (L.) Cronquist, Lolium multiflorum Lam., Digitaria insularis (L.) Mez ex Ekman, and Euphorbia heterophylla L., have evolved resistance to glyphosate in GRS in Brazil. Conyza spp. are the most difficult to control. A glyphosate-resistant biotype of Sorghum halepense L. has evolved in GRS in Argentina and one of D. insularis in Paraguay. The following actions are proposed to minimize weed resistance problem: (a) rotation of GRS with conventional soybeans in order to rotate herbicide modes of action; (b) avoidance of lower than recommended glyphosate rates; (c) keeping soil covered with a crop or legume at intercrop intervals; (d) keeping machinery free of weed seeds; and (d) use of a preplant nonselective herbicide plus residuals to eliminate early weed interference with the crop and to minimize escapes from later applications of glyphosate due to natural resistance of older weeds and/or incomplete glyphosate coverage.

Cerdeira AL; Gazziero DL; Duke SO; Matallo MB

2011-06-01

119

Glyphosate drift promotes changes in fitness and transgene gene flow in canola (Brassica napus) and hybrids.  

UK PubMed Central (United Kingdom)

BACKGROUND AND AIMS: With the advent of transgenic crops, genetically modified, herbicide-resistant Brassica napus has become a model system for examining the risks and potential ecological consequences of escape of transgenes from cultivation into wild compatible species. Escaped transgenic feral B. napus and hybrids with compatible weedy species have been identified outside of agriculture and without the apparent selection for herbicide resistance. However, herbicide (glyphosate) exposure can extend beyond crop field boundaries, and a drift-level of herbicide could function as a selective agent contributing to increased persistence of transgenes in the environment. METHODS: The effects of a drift level (0·1 × the field application rate) of glyphosate herbicide and varied levels of plant competition were examined on plant fitness-associated traits and gene flow in a simulated field plot, common garden experiment. Plants included transgenic, glyphosate-resistant B. napus, its weedy ancestor B. rapa, and hybrid and advanced generations derived from them. KEY RESULTS: The results of this experiment demonstrate reductions in reproductive fitness for non-transgenic genotypes and a contrasting increase in plant fitness for transgenic genotypes as a result of glyphosate-drift treatments. Results also suggest that a drift level of glyphosate spray may influence the movement of transgenes among transgenic crops and weeds and alter the processes of hybridization and introgression in non-agronomic habitats by impacting flowering phenology and pollen availability within the community. CONCLUSIONS: The results of this study demonstrate the potential for persistence of glyphosate resistance transgenes in weedy plant communities due to the effect of glyphosate spray drift on plant fitness. Additionally, glyphosate drift has the potential to change the gene-flow dynamics between compatible transgenic crops and weeds, simultaneously reducing direct introgression into weedy species while contributing to an increase in the transgenic seed bank.

Londo JP; Bautista NS; Sagers CL; Lee EH; Watrud LS

2010-12-01

120

Understanding the combined influence of fine sediment and glyphosate herbicide on stream periphyton communities.  

UK PubMed Central (United Kingdom)

Pesticides and deposited fine sediment have independently been associated with changes in relative abundance and species richness in aquatic ecosystems, but the interplay between these two stressors in agricultural streams is poorly understood. A 28-day experiment in outdoor stream mesocosms examined the effects of four levels each of fine sediment coverage (0, 25, 75, 100%) and glyphosate-based herbicide concentration (0, 50, 200, 370 ?g/L) on periphyton communities (algae and bacteria) in a fully factorial, repeated-measures design. Our aims were to determine whether (i) increased levels of sediment and glyphosate had individual and/or additive effects, (ii) increased sediment reduced the toxicity of glyphosate (antagonistic multiple stressor interaction), or (iii) sediment-adsorbed glyphosate prolonged the effects of exposure (synergistic interaction). We also assigned all algal taxa to three ecological guilds (low-profile, high-profile and motile growth forms) and separately determined their responses to the treatments. As individual stressors, sediment addition affected all algal community-level metrics, whereas glyphosate addition only affected algal community evenness. Bacterial taxon richness was unaffected by either stressor. In combination, however, significant overall sediment by glyphosate interactions were detected, demonstrating synergistic (algal evenness, high-profile and motile guilds) or antagonistic effects (low-profile guild). Our experiment underscores the importance of considering both structural and functional indicators, including algal guild representation, when assessing the mechanisms by which periphyton communities respond to multiple stressors.

Magbanua FS; Townsend CR; Hageman KJ; Lange K; Lear G; Lewis GD; Matthaei CD

2013-09-01

 
 
 
 
121

Understanding the combined influence of fine sediment and glyphosate herbicide on stream periphyton communities.  

Science.gov (United States)

Pesticides and deposited fine sediment have independently been associated with changes in relative abundance and species richness in aquatic ecosystems, but the interplay between these two stressors in agricultural streams is poorly understood. A 28-day experiment in outdoor stream mesocosms examined the effects of four levels each of fine sediment coverage (0, 25, 75, 100%) and glyphosate-based herbicide concentration (0, 50, 200, 370 ?g/L) on periphyton communities (algae and bacteria) in a fully factorial, repeated-measures design. Our aims were to determine whether (i) increased levels of sediment and glyphosate had individual and/or additive effects, (ii) increased sediment reduced the toxicity of glyphosate (antagonistic multiple stressor interaction), or (iii) sediment-adsorbed glyphosate prolonged the effects of exposure (synergistic interaction). We also assigned all algal taxa to three ecological guilds (low-profile, high-profile and motile growth forms) and separately determined their responses to the treatments. As individual stressors, sediment addition affected all algal community-level metrics, whereas glyphosate addition only affected algal community evenness. Bacterial taxon richness was unaffected by either stressor. In combination, however, significant overall sediment by glyphosate interactions were detected, demonstrating synergistic (algal evenness, high-profile and motile guilds) or antagonistic effects (low-profile guild). Our experiment underscores the importance of considering both structural and functional indicators, including algal guild representation, when assessing the mechanisms by which periphyton communities respond to multiple stressors. PMID:23866128

Magbanua, Francis S; Townsend, Colin R; Hageman, Kimberly J; Lange, Katharina; Lear, Gavin; Lewis, Gillian D; Matthaei, Christoph D

2013-06-05

122

Control of glyphosate resistant hairy fleabane (Conyza bonariensis) with dicamba and 2,4-D/ Controle de buva (Conyza bonariensis) resistente ao glyphosate com dicamba e 2,4-D  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Os herbicidas mimetizadores de auxinas como dicamba e 2,4-D são alternativas para o controle de buva resistente ao glyphosate. Com a possível futura liberação comercial de culturas resistentes ao dicamba e 2,4-D, a aplicação destes herbicidas reguladores de crescimento será uma provável alternativa de controle de buva resistente ao glyphosate. O objetivo desta pesquisa foi modelar por meio de curvas de dose-resposta a eficácia do dicamba e 2,4-D isolados e dicamb (more) a em associação com glyphosate para controle de uma população de buva resistente. Um estudo de doseresposta em casa de vegetação foi conduzido em delineamento experimental inteiramente casualizado, sendo que as doses utilizadas para a construção das curvas de dose-resposta foram de 0, 120, 240, 480, 720 e 960 g i.a. ha-1de para o dicamba e o 2,4-D isolados e dicamba associado com 540 g e.a. ha-1 de glyphosate. As doses utilizadas para o glyphosate isolado foram de 0, 180, 360, 540, 720 e 960 g e.a. ha-1. Os tratamentos herbicidas foram aplicados quando asplantas estavam no estádio vegetativo de 10 a 12 folhas e altura entre 12 e 15 cm. A buva apresentou baixa sensibilidade ao glyphosate, pois não foi controlada mesmo na dose de 960 g e.a. ha-1 de glyphosate. O dicamba e o 2,4-D foram eficazes no controle da população de buva estudada. A buva responde de forma diferenciada ao 2,4-D e dicamba e será importante determinaras doses apropriadas de cada herbicida para controle de buva resistente ao glyphosate em condições de campo. A associação de glyphosate e dicamba não foi antagônica no controle da buva e o glyphosate pode causar um efeito aditivo no controle, apesar da resistência da população. Abstract in english Auxyn type herbicides such as dicamba and 2,4-D are alternative herbicides that can be used to control glyphosate-resistant hairy fleabane. With the forthcoming possibility of releasing dicamba-resistant and 2,4-D-resistant crops, use of these growth regulator herbicides will likely be an alternative that can be applied to the control of glyphosate resistant hairy fleabane (Conyza bonariensis). The objective of this research was to model the efficacy, through dose-respons (more) e curves, of glyphosate, 2,4-D, isolated dicamba and glyphosatedicamba combinations to control a brazilian hairy fleabane population resistant to glyphosate. The greenhouse dose-response studies were conducted as a completely randomized experimental design, and the rates used for dose response curve construction were 0, 120, 240, 480, 720 and 960 g a.i. ha-1 for 2,4-D, dicamba and the dicamba combination, with glyphosate at 540 g a.e. ha-1. The rates for glyphosate alone were 0, 180, 360, 540, 720 and 960 g a.e. ha-1. Herbicides were applied when the plants were in a vegetative stage with 10 to 12 leaves and height between 12 and 15 cm. Hairy fleabane had low sensitivity to glyphosate, with poor control even at the 960 g a.e. ha-1 rate. Dicamba and 2,4-D were effective in controlling the studied hairy fleabane. Hairy fleabane responds differently to 2,4-D and dicamba. The combination of glyphosate and dicamba was not antagonistic to hairy fleabane control, and glyphosate may cause an additive effect on the control, despite the population resistance.

Soares, D.J.; Oliveira, W.S.; López-Ovejero, R.F.; Christoffoleti, P.J

2012-06-01

123

Control of glyphosate resistant hairy fleabane (Conyza bonariensis) with dicamba and 2,4-D Controle de buva (Conyza bonariensis) resistente ao glyphosate com dicamba e 2,4-D  

Directory of Open Access Journals (Sweden)

Full Text Available Auxyn type herbicides such as dicamba and 2,4-D are alternative herbicides that can be used to control glyphosate-resistant hairy fleabane. With the forthcoming possibility of releasing dicamba-resistant and 2,4-D-resistant crops, use of these growth regulator herbicides will likely be an alternative that can be applied to the control of glyphosate resistant hairy fleabane (Conyza bonariensis). The objective of this research was to model the efficacy, through dose-response curves, of glyphosate, 2,4-D, isolated dicamba and glyphosatedicamba combinations to control a brazilian hairy fleabane population resistant to glyphosate. The greenhouse dose-response studies were conducted as a completely randomized experimental design, and the rates used for dose response curve construction were 0, 120, 240, 480, 720 and 960 g a.i. ha-1 for 2,4-D, dicamba and the dicamba combination, with glyphosate at 540 g a.e. ha-1. The rates for glyphosate alone were 0, 180, 360, 540, 720 and 960 g a.e. ha-1. Herbicides were applied when the plants were in a vegetative stage with 10 to 12 leaves and height between 12 and 15 cm. Hairy fleabane had low sensitivity to glyphosate, with poor control even at the 960 g a.e. ha-1 rate. Dicamba and 2,4-D were effective in controlling the studied hairy fleabane. Hairy fleabane responds differently to 2,4-D and dicamba. The combination of glyphosate and dicamba was not antagonistic to hairy fleabane control, and glyphosate may cause an additive effect on the control, despite the population resistance.Os herbicidas mimetizadores de auxinas como dicamba e 2,4-D são alternativas para o controle de buva resistente ao glyphosate. Com a possível futura liberação comercial de culturas resistentes ao dicamba e 2,4-D, a aplicação destes herbicidas reguladores de crescimento será uma provável alternativa de controle de buva resistente ao glyphosate. O objetivo desta pesquisa foi modelar por meio de curvas de dose-resposta a eficácia do dicamba e 2,4-D isolados e dicamba em associação com glyphosate para controle de uma população de buva resistente. Um estudo de doseresposta em casa de vegetação foi conduzido em delineamento experimental inteiramente casualizado, sendo que as doses utilizadas para a construção das curvas de dose-resposta foram de 0, 120, 240, 480, 720 e 960 g i.a. ha-1de para o dicamba e o 2,4-D isolados e dicamba associado com 540 g e.a. ha-1 de glyphosate. As doses utilizadas para o glyphosate isolado foram de 0, 180, 360, 540, 720 e 960 g e.a. ha-1. Os tratamentos herbicidas foram aplicados quando asplantas estavam no estádio vegetativo de 10 a 12 folhas e altura entre 12 e 15 cm. A buva apresentou baixa sensibilidade ao glyphosate, pois não foi controlada mesmo na dose de 960 g e.a. ha-1 de glyphosate. O dicamba e o 2,4-D foram eficazes no controle da população de buva estudada. A buva responde de forma diferenciada ao 2,4-D e dicamba e será importante determinaras doses apropriadas de cada herbicida para controle de buva resistente ao glyphosate em condições de campo. A associação de glyphosate e dicamba não foi antagônica no controle da buva e o glyphosate pode causar um efeito aditivo no controle, apesar da resistência da população.

D.J. Soares; W.S. Oliveira; R.F. López-Ovejero; P.J Christoffoleti

2012-01-01

124

Bermudagrass (Cynodon spp) dose-response relationships with clethodim, glufosinate and glyphosate.  

UK PubMed Central (United Kingdom)

Greenhouse studies were conducted to evaluate the sensitivity of three commercial cultivars, eight experimental cultivars and common bermudagrass to clethodim, glufosinate and glyphosate. Each herbicide was applied at eight doses. Data were regressed on herbicide dose using a log-logistic curve (R2 = 0.56-0.95 for clethodim, R2 = 0.60-0.94 for glufosinate, and R2 = 0.70-0.96 for glyphosate). The herbicide rate that elicited a 50% plant response (I50) in the bermudagrass cultivars ranged from 0.04 to 0.19 kg ha(-1) clethodim, 0.19 to 1.33 kg ha(-1) glufosinate and 0.34 to 1.14 kg ha(-1) glyphosate. Relative to other cultivars, common bermudagrass was intermediate in its response to clethodim and among the most tolerant cultivars to glufosinate and glyphosate. TifSport was relatively tolerant to clethodim and glufosinate compared with other cultivars, but relatively sensitive to glyphosate. One cultivar, 94-437, was consistently among the most sensitive cultivars to each of the herbicides. While there were differential herbicide tolerances among the tested bermudagrass cultivars, there did not appear to be any naturally occurring herbicide resistance that could be commercially utilized. However, research indicated that breeding efforts should target herbicide resistance that is at least four times the registered use rate. Also, TifSport and Tifway have been identified as suitable representatives of triploid hybrid bermudagrass cultivars to be used to evaluate the success of turfgrass renovation programs.

Webster TM; Hanna WW; Mullinix BG Jr

2004-12-01

125

Buva (Conyza bonariensis) resistente ao glyphosate na região sul do Brasil Conyza bonariensis biotypes resistant to the glyphosate in southern Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available O glyphosate é um herbicida não-seletivo utilizado para controlar plantas daninhas há mais de 20 anos no Rio Grande do Sul. A buva (Conyza bonariensis) é uma espécie daninha comum nos Estados da região Sul do Brasil e tradicionalmente controlada com uso de glyphosate. Entretanto, nos últimos anos plantas de buva têm apresentado poucos sintomas de toxicidade em resposta ao tratamento com glyphosate, sugerindo que estas plantas são resistentes ao herbicida. Assim, com o objetivo de avaliar a resposta de uma população de plantas de buva a glyphosate, foram realizados três experimentos: um em campo e dois em casa de vegetação. No experimento em campo, os tratamentos avaliados constaram de doses crescentes de glyphosate (0, 360, 720, 1.440, 2.880 e 5.760 g ha-1), e os herbicidas paraquat (400 g ha-1) e 2,4-D (1.005 g ha-1) foram empregados como produtos testemunhas, com diferentes mecanismos de ação nas plantas. No experimento em casa de vegetação os tratamentos constaram de doses crescentes de glyphosate (0, 360, 720, 1.440, 2.880 e 5.760 g ha-1), mais os herbicidas testemunhas, aplicados sobre plantas de um biótipo considerado resistente e de outro considerado sensível. No segundo experimento realizado em casa de vegetação, foram avaliados os tratamentos contendo glyphosate (720, 1.440 e 2.880 g ha-1), mais os herbicidas chlorimuron-ethyl (40 g ha-1), metsulfuron-methyl (4 g ha-1), 2,4-D (1.005 g ha-1), paraquat (400 g ha-1) e diuron + paraquat (200 + 400 g ha-1), bem como a testemunha sem tratamento herbicida. A toxicidade dos tratamentos herbicidas foi avaliada aos 7, 15 e 30 DAT (dias após tratamento). Os resultados obtidos nos experimentos em condições de campo e em casa de vegetação, de forma geral, evidenciam que o biótipo sensível é controlado pelo glyphosate e pelos demais herbicidas avaliados. Demonstram ainda que o biótipo resistente apresenta-se, igualmente ao biótipo sensível, altamente suscetível aos herbicidas com mecanismo de ação distinto daquele do glyphosate. Entretanto, o biótipo resistente mostra baixa resposta ao herbicida glyphosate, mesmo se este for empregado em doses elevadas, evidenciando ter adquirido resistência a esse produto.Glyphosate is a non-selective herbicide used for over 20 years to control weeds in Rio Grande do Sul. Horseweed (Conyza bonariensis) is a common weed in Rio Grande do Sul and traditionally sensitive to glyphosate. However, during the last years, some horseweed plants have not shown significant injury symptoms after treatment with glyphosate, suggesting that they are resistant to this herbicide. Aiming to evaluate the response of a population of horseweed plants to glyphosate, one field and two greenhouse experiments were carried out. The field experiment treatment had increasing rates of glyphosate (0, 360, 720, 1,440, 2,880 and 5,760 g ha-1), and also the herbicides paraquat and 2,4-D as standards. The greenhouse experiments had increasing rates of glyphosate (0, 360, 720, 1,440, 2,880 and 5,760 g ha-1) plus the above listed check herbicides sprayed on biotypes considered resistant and on plants of one susceptible biotype. In the second greenhouse experiment, the treatments were increasing rates of glyphosate (720, 1,440 and 2,880 g ha-1) and herbicides chlorimuron-ethyl, metsulfuron-methyl, 2,4-D, paraquat and diuron + paraquat sprayed on plants of resistant and susceptible biotypes. Horseweed control was accessed at 7, 15 and 30 DAT (days after treatment). Overall results of the field and greenhouse experiments provided evidence that the susceptible biotype is easily controlled by glyphosate and the other tested herbicides. In addition, the results demonstrated that the resistant biotype, as the susceptible biotype, is highly sensitive to herbicides with mode of action that differs from glyphosate. However, the resistant biotype showed low response to glyphosate, even at very high rates, confirming resistance of this horseweed population to glyphosate.

L. Vargas; M.A. Bianchi; M.A. Rizzardi; D. Agostinetto; T. Dal Magro

2007-01-01

126

Efeitos da chuva na eficiência de formulações e doses de glyphosate no controle de Brachiaria decumbens Rainfall effects on glyphosate formulation and rate the efficiency to control of Brachiaria decumbens  

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Full Text Available O objetivo deste trabalho foi de avaliar os efeitos de doses das formulações de glyphosate - amônio, isopropilamina e potássico - sobre o controle de plantas de Brachiaria decumbens, em condições controladas, quando submetidas à chuva com intensidade de 20 mm e durante 30 minutos, em intervalos de 1, 2, 4, 6, 12 e 24 horas após aplicação dos tratamentos herbicidas. A ocorrência de chuvas após a aplicação de glyphosate reduziu o controle de B. decumbens, e essa redução foi maior com a diminuição do intervalo sem chuva após a aplicação. As aplicações das formulações de glyphosate potássico e isopropilamina resultaram em maior controle da B. decumbens que a formulação de glyphosate amônico. Esse efeito foi também observado no acúmulo de matéria seca da rebrota da planta daninha, avaliada aos 19 dias após o corte da parte aérea das plantas. Foram necessários intervalos de pelo menos 8, 11 e 12 horas sem chuva após aplicação, respectivamente para glyphosate potássico, isopropilamina e amônio, na dose de 1.440 g ha-1, para obter controle maior que 80%. Na dose de 2.160 g ha-1 necessitou-se de intervalos de pelo menos 5, 7 e 9 horas sem chuva, respectivamente para as formulações de glyphosate potássico, isopropilamina e amônio, para proporcionar o mesmo controle de B. decumbens. Na avaliação da matéria seca acumulada na rebrota, o glyphosate potássico proporcionou controle excelente da espécie (rebrota menor do que 5%) a partir de quatro e cinco horas sem chuva após aplicação, respectivamente nas duas maiores doses (2.160 e 1.440 g ha-1). No caso do glyphosate isopropilamina, nas doses de 2.160 e 1.440 g ha-1, o mesmo controle foi obtido a partir de 7 e 12 horas sem chuva, respectivamente. Concluiu-se que as formulações glyphosate potássico e isopropilamina são menos afetadas pela ocorrência de chuva após a aplicação e demandam menor intervalo livre de chuva do que o glyphosate amônio.The objective of this study was to evaluate the dose effects the glyphosate formulations - ammonium, isopropylamine and potassic - on Brachiaria decumbens plant control, under controlled conditions, when submitted to 20 mm of rainfall intensity for 30 minutes, at intervals of 1, 2, 4, 6, 12 and 24 hours after application of the herbicide treatments. Rainfall events after glyphosate application reduced the control of B. decumbens and this reduction was higher as the rainfall event was closer to the herbicide application. Potassic and isopropylamine glyphosate formulations showed a higher control of B. decumbens than ammonium glyphosate formulation. This effect was also observed on the dry biomass accumulation of B. decumbens regrowth, which was evaluated at 19 days after excising the plantshoot. At least 8, 11 and 12 hours after glyphosate application without rainfall were required, respectively, for potassic, isopropylamine and ammonium glyphosate at the dose of 1,440 g ha-1, to obtain a control over 80%; however, for the rate of 2,160 g ha-1, intervals required were 5, 7, and 9 hours, at least, respectively, to obtain the same control of B. decumbens. Dry biomass accumulation oduring weed regrowth was lower than 5%, providing an excellent control of the weed when four to five hours without rainfall occurred after herbicide application at the highest two doses (2,160 and 1,440 g ha-1). For isopropylamine glyphosate at the doses of 2,160 and 1,440 g ha-1, the same control was obtained from 7 and 12 hours without rainfall, respectively. It was concluded that both the potassic and isopropylamine glyphosate formulations are less affected by rainfall events after herbicide application, tolerating rainfall in a shorter interval after herbicide application than ammonium glyphosate.

R.C. Werlang; A.A. Silva; L.R. Ferreira; G.V. Miranda

2003-01-01

127

Glyphosate-degrading microorganisms from industrial activated sludge.  

Science.gov (United States)

A plating medium was developed to isolate N-phosphonomethylglycine (glyphosate)-degrading microorganisms, with glyphosate as the sole phosphorus source. Two industrial biosystems treating glyphosate wastes contained elevated microbial counts on the medium. One purified isolate metabolized glyphosate to aminomethylphosphonic acid, mineralizing this accumulating intermediate during log growth. This microorganism has been identified as a Flavobacterium species. PMID:16346999

Balthazor, T M; Hallas, L E

1986-02-01

128

Glyphosate-degrading microorganisms from industrial activated sludge.  

UK PubMed Central (United Kingdom)

A plating medium was developed to isolate N-phosphonomethylglycine (glyphosate)-degrading microorganisms, with glyphosate as the sole phosphorus source. Two industrial biosystems treating glyphosate wastes contained elevated microbial counts on the medium. One purified isolate metabolized glyphosate to aminomethylphosphonic acid, mineralizing this accumulating intermediate during log growth. This microorganism has been identified as a Flavobacterium species.

Balthazor TM; Hallas LE

1986-02-01

129

ALKOXYLATED ALKYLAMINE QUATERNARY SURFACTANTS FOR GLYPHOSATE  

UK PubMed Central (United Kingdom)

The present invention relates to stable glyphosate formulations with improved efficacy by a highly effective alkoxylated alkylamine quaternary surfactant at a very low used level. The alkoxylated alkylamine quaternary surfactant is compatible in all salts of glyphosate formulations (including potassium and ammonium) EVEN AT VERY HIGH CONCENTRATION (470-600 g a.e./l).

ZHU SHAWN; ABRAHAM WILLIAM; HEMMINGHAUS JOHN

130

Glyphosate-resistant goosegrass from Mississippi  

Science.gov (United States)

A glyphosate resistant population of goosegrass (Eleusine indica (L.) Gaertn.) was documented near Stoneville, Mississippi, USA, in an area which had received multiple applications of glyphosate each year for the previous eleven years. Resistance ratios based on dose response growth reduction assays...

131

Influence of glyphosate and its formulation (Roundup[reg]) on the toxicity and bioavailability of metals to Ceriodaphnia dubia  

Energy Technology Data Exchange (ETDEWEB)

This study examined the toxicological interaction between glyphosate (or its formulation, Roundup[reg]) and several heavy metals to a freshwater cladoceran, Ceriodaphnia dubia. We demonstrated that all binary combinations of Roundup[reg] and metals (Cd, Cu, Cr, Ni, Pb, Se and Zn) exhibited 'less than additive' mixture toxicity, with 48-h LC50 toxic unit>1. Addition of glyphosate alone could significantly reduce the acute toxicity of Ag, Cd, Cr, Cu, Ni, Pb and Zn (but not Hg and Se). The ratio between glyphosate and metal ions was important in determining the mitigation of metal toxicity by glyphosate. A bioaccumulation study showed that in the presence of glyphosate the uptake of some metals (e.g. Ag) was halted but that of others (e.g. Hg) was increased significantly. Therefore, our study strongly suggests that glyphosate and its commercial formulations can control the toxicity as well as the bioavailability of heavy metals in aquatic ecosystems where both groups of chemicals can co-occur. - Glyphosate can control the toxicity and bioavailability of many heavy metals in the aquatic environment.

Tsui, Martin T.K. [Department of Biology, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong (China); Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong (China); Wang Wenxiong [Department of Biology, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong (China); Chu, L.M. [Department of Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong (China)]. E-mail: leemanchu@cuhk.edu.hk

2005-11-15

132

Influence of glyphosate and its formulation (Roundup[reg]) on the toxicity and bioavailability of metals to Ceriodaphnia dubia  

International Nuclear Information System (INIS)

This study examined the toxicological interaction between glyphosate (or its formulation, Roundup[reg]) and several heavy metals to a freshwater cladoceran, Ceriodaphnia dubia. We demonstrated that all binary combinations of Roundup[reg] and metals (Cd, Cu, Cr, Ni, Pb, Se and Zn) exhibited 'less than additive' mixture toxicity, with 48-h LC50 toxic unit>1. Addition of glyphosate alone could significantly reduce the acute toxicity of Ag, Cd, Cr, Cu, Ni, Pb and Zn (but not Hg and Se). The ratio between glyphosate and metal ions was important in determining the mitigation of metal toxicity by glyphosate. A bioaccumulation study showed that in the presence of glyphosate the uptake of some metals (e.g. Ag) was halted but that of others (e.g. Hg) was increased significantly. Therefore, our study strongly suggests that glyphosate and its commercial formulations can control the toxicity as well as the bioavailability of heavy metals in aquatic ecosystems where both groups of chemicals can co-occur. - Glyphosate can control the toxicity and bioavailability of many heavy metals in the aquatic environment.

2005-01-01

133

RDX-based nanocomposite microparticles for significantly reduced shock sensitivity  

International Nuclear Information System (INIS)

[en] Cyclotrimethylenetrinitramine (RDX)-based nanocomposite microparticles were produced by a simple, yet novel spray drying method. The microparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and high performance liquid chromatography (HPLC), which shows that they consist of small RDX crystals (?0.1-1 ?m) uniformly and discretely dispersed in a binder. The microparticles were subsequently pressed to produce dense energetic materials which exhibited a markedly lower shock sensitivity. The low sensitivity was attributed to small crystal size as well as small void size (?250 nm). The method developed in this work may be suitable for the preparation of a wide range of insensitive explosive compositions.

2011-01-15

134

RDX-based nanocomposite microparticles for significantly reduced shock sensitivity  

Energy Technology Data Exchange (ETDEWEB)

Cyclotrimethylenetrinitramine (RDX)-based nanocomposite microparticles were produced by a simple, yet novel spray drying method. The microparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and high performance liquid chromatography (HPLC), which shows that they consist of small RDX crystals ({approx}0.1-1 {mu}m) uniformly and discretely dispersed in a binder. The microparticles were subsequently pressed to produce dense energetic materials which exhibited a markedly lower shock sensitivity. The low sensitivity was attributed to small crystal size as well as small void size ({approx}250 nm). The method developed in this work may be suitable for the preparation of a wide range of insensitive explosive compositions.

Qiu Hongwei, E-mail: hqiu@stevens.edu [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Stepanov, Victor; Di Stasio, Anthony R. [U.S. Army - Armament Research, Development, and Engineering Center, Picatinny, NJ 07806 (United States); Chou, Tsengming; Lee, Woo Y. [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)

2011-01-15

135

Glyphosate degradation by immobilized bacteria: laboratory studies showing feasibility for glyphosate removal from waste water.  

Science.gov (United States)

To evaluate immobilized bacteria technology for the removal of low levels of glyphosate (N-phosphonomethylglycine) from aqueous industrial effluents, microorganisms with glyphosate-degrading activity obtained from a fill and draw enrichment reactor inoculated with activated sludge were first exposed to glyphosate production wastes containing 500-2000 mg glyphosate/L. The microorganisms were then immobilized by adsorption onto a diatomaceous earth biocarrier contained in upflow Plexiglas columns. The columns were aerated, maintained at pH 7.0-8.0, incubated at 25 degrees C, supplemented with NH4NO3 (50 mg/L), and exposed to glyphosate process wastes pumped upflow through the biocarrier. Glyphosate degradation to aminomethylphosphonic acid was initially > 96% for 21 days of operation at flows yielding hydraulic residence times (HRTs) as short as 42 min. Higher flow rate studies showed > 98% removal of 50 mg glyphosate/L from the waste stream could be achieved at a HRT of 23 min. Glyphosate removal of > 99% at a 37-min HRT was achieved under similar conditions with a column inoculated with a pure culture of Pseudomonas sp. strain LBr, a bacterium known to have high glyphosate-degrading activity. After acid shocking (pH 2.8 for 18 h) of a column of immobilized bacteria, glyphosate-degrading activity was regained within 4 days without reinoculation. Although microbial growth and glyphosate degradation were not maintained under low organic nutrient conditions in the laboratory, the low levels of degradable carbon (45-94 mg/L) in the industrial effluent were sufficient to support prolonged glyphosate-degrading activity. The results demonstrated that immobilized bacteria technology is effective in removing low levels of glyphosate in high-volume liquid waste streams. PMID:1464067

Heitkamp, M A; Adams, W J; Hallas, L E

1992-09-01

136

Glyphosate degradation by immobilized bacteria: laboratory studies showing feasibility for glyphosate removal from waste water.  

UK PubMed Central (United Kingdom)

To evaluate immobilized bacteria technology for the removal of low levels of glyphosate (N-phosphonomethylglycine) from aqueous industrial effluents, microorganisms with glyphosate-degrading activity obtained from a fill and draw enrichment reactor inoculated with activated sludge were first exposed to glyphosate production wastes containing 500-2000 mg glyphosate/L. The microorganisms were then immobilized by adsorption onto a diatomaceous earth biocarrier contained in upflow Plexiglas columns. The columns were aerated, maintained at pH 7.0-8.0, incubated at 25 degrees C, supplemented with NH4NO3 (50 mg/L), and exposed to glyphosate process wastes pumped upflow through the biocarrier. Glyphosate degradation to aminomethylphosphonic acid was initially > 96% for 21 days of operation at flows yielding hydraulic residence times (HRTs) as short as 42 min. Higher flow rate studies showed > 98% removal of 50 mg glyphosate/L from the waste stream could be achieved at a HRT of 23 min. Glyphosate removal of > 99% at a 37-min HRT was achieved under similar conditions with a column inoculated with a pure culture of Pseudomonas sp. strain LBr, a bacterium known to have high glyphosate-degrading activity. After acid shocking (pH 2.8 for 18 h) of a column of immobilized bacteria, glyphosate-degrading activity was regained within 4 days without reinoculation. Although microbial growth and glyphosate degradation were not maintained under low organic nutrient conditions in the laboratory, the low levels of degradable carbon (45-94 mg/L) in the industrial effluent were sufficient to support prolonged glyphosate-degrading activity. The results demonstrated that immobilized bacteria technology is effective in removing low levels of glyphosate in high-volume liquid waste streams.

Heitkamp MA; Adams WJ; Hallas LE

1992-09-01

137

The use of environmental metabolomics to determine glyphosate level of exposure in rapeseed (Brassica napus L.) seedlings  

International Nuclear Information System (INIS)

Metabolic profiling in plants can be used to differentiate between treatments and to search for biomarkers for exposure. A methodology for processing Ultra-High-Performance Liquid Chromatography-Diode-Array-Detection data is devised. This methodology includes a scheme for selecting informative wavelengths, baseline removal, retention time alignment, selection of relevant retention times, and principal component analysis (PCA). Plant crude extracts from rapeseed seedling exposed to sublethal concentrations of glyphosate are used as a study case. Through this approach, plants exposed to concentrations down to 5 ?M could be distinguished from the controls. The compounds responsible for this differentiation were partially identified and were different from those specific for high exposure samples, which suggests that two different responses to glyphosate are elicited in rapeseed depending on the level of exposure. The PCA loadings indicate that a combination of other metabolites could be more sensitive than the response of shikimate to detect glyphosate exposure. - Highlights: ? A method for processing UHPLC-DAD data for plant metabolic profiling is devised. ? The metabolic profiling approach is more sensitive to glyphosate exposure than shikimate. ? Plants exposed to concentrations down to 5 ?M can be distinguished from the controls. ? Two different responses to glyphosate may be elicited in rapeseed depending on the level of exposure. - A novel untargeted environmental metabololomic approach is used to detect low-level glyphosate exposure of rapeseed seedlings.

2011-01-01

138

The use of environmental metabolomics to determine glyphosate level of exposure in rapeseed (Brassica napus L.) seedlings  

Energy Technology Data Exchange (ETDEWEB)

Metabolic profiling in plants can be used to differentiate between treatments and to search for biomarkers for exposure. A methodology for processing Ultra-High-Performance Liquid Chromatography-Diode-Array-Detection data is devised. This methodology includes a scheme for selecting informative wavelengths, baseline removal, retention time alignment, selection of relevant retention times, and principal component analysis (PCA). Plant crude extracts from rapeseed seedling exposed to sublethal concentrations of glyphosate are used as a study case. Through this approach, plants exposed to concentrations down to 5 {mu}M could be distinguished from the controls. The compounds responsible for this differentiation were partially identified and were different from those specific for high exposure samples, which suggests that two different responses to glyphosate are elicited in rapeseed depending on the level of exposure. The PCA loadings indicate that a combination of other metabolites could be more sensitive than the response of shikimate to detect glyphosate exposure. - Highlights: > A method for processing UHPLC-DAD data for plant metabolic profiling is devised. > The metabolic profiling approach is more sensitive to glyphosate exposure than shikimate. > Plants exposed to concentrations down to 5 {mu}M can be distinguished from the controls. > Two different responses to glyphosate may be elicited in rapeseed depending on the level of exposure. - A novel untargeted environmental metabololomic approach is used to detect low-level glyphosate exposure of rapeseed seedlings.

Petersen, Iben Lykke; Tomasi, Giorgio; Sorensen, Hilmer; Boll, Esther S.; Hansen, Hans Christian Bruun [Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C (Denmark); Christensen, Jan H., E-mail: jch@life.ku.dk [Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C (Denmark)

2011-10-15

139

Interação de glyphosate com carfentrazone-ethyl/ Glyphosate - carfentrazone-ethyl interaction  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Foi conduzido um experimento em condições controladas para determinar a interação do carfentrazone-ethyl em mistura no tanque com o herbicida glyphosate, no controle de seis espécies de plantas daninhas. Glyphosate aplicado isoladamente na dose de 720 g ha-1 foi eficaz no controle de Amaranthus hybridus (100%), Desmodium tortuosum (100%), Bidens pilosa (99%), Eleusine indica (96%), Digitaria horizontalis (100%) e Commelina benghalensis (93%) aos 21 DAA. Carfentrazone (more) -ethyl aplicado isoladamente controlou eficazmente C. benghalensis. As misturas de glyphosate nas doses de 252 e 720 g ha-1 com carfentrazone-ethyl nas doses de 15 e 30 g ha¹ demonstraram efeito aditivo no controle de A. hybridus, D. tortuosum e Bidens pilosa, à exceção das misturas de glyphosate na dose de 252 g ha-1 com as doses de 15 e 30 g ha-1 de carfentrazone-ethyl, que proporcionam efeito sinergístico no controle de D. tortuosum. A adição das duas doses de carfentrazone-ethyl antagonizou o efeito de glyphosate na menor dose (252 g ha-1) no controle de E. indica, apresentando, no entanto, efeito aditivo com o glyphosate na maior dose (720 g ha-1). Já para D. horizontalis, as misturas de carfentrazone-ethyl com glyphosate na menor dose (252 g ha-1) apresentaram efeito sinergístico no controle dessa espécie, demonstrando, ainda, efeito aditivo na mistura com glyphosate na dose de 720 g ha-1. A mistura de carfentrazone-ethyl com glyphosate proporcionou efeito aditivo no controle de C. benghalensis, independentemente das combinações de doses avaliadas. Os resultados deste experimento indicam que carfentrazone-ethyl apresenta comportamento diferenciado quanto à interação com glyphosate, dependendo da espécie de planta daninha e da dose dos herbicidas utilizados na mistura em tanque, sendo complementar na mistura em tanque com glyphosate, pois demonstrou efeito antagônico em poucas das combinações estudadas, prevalecendo seu efeito aditivo na mistura com glyphosate, no controle das espécies avaliadas. Abstract in english Under evironmental controlled conditions experiments were conducted to determine the efficacy of carfentrazone-ethyl in tank mixture with glyphosate to control six weed species. Glyphosate alone at 720 g ha-1 was effective in controlling Amaranthus hybridus (100%), Desmodium tortuosum (100%), Bidens pilosa (99%), Eleusine indica (96%), Digitaria horizontalis (100%) and Commelina benghalensis (93%) at 21 DAA. Carfentrazone-ethyl alone controlled only C. benghalensis. effic (more) iently. Glyphosate mixtures (252 and 720 g ha-1) with carfentrazone-ethyl at 15 and 30 g ha¹ showed an additive effect in controlling A. hybridus, D. tortuosum and Bidens pilosa, except for glyphosate mixture at 252 g ha-1 with carfentrazone-ethyl at 15 and 30 g ha-1, which showed synergism in controlling D. tortuosum. The addition of the two carfentrazone-ethyl doses antagonized the effect of the smallest dose (252 g ha-1) of glyphosate on E. indica control. However, the largest glyphosate dose (720 g ha-1) provided additive effect when mixed with both carfentrazone-ethyl doses. For D. horizontalis, carfentrazone-ethyl mixtures with glyphosate in the smallest dose (252 g ha-1) had a synergistic effect in the control of this species, also showing and additive effect in the mixture with glyphosate at 720 g ha-1. Carfentrazone-ethyl mixture with glyphosate provided an additive effect in C. benghalensis control, regardless of dose combinations. The results of this experiment indicate that carfentrazone-ethyl presents a differentiated behavior when interacting with glyphosate, depending on the weed species and the herbicide dose used in the tank mixtures, being complementary in tank-mix combinations with glyphosate, since it showed an antagonistic effect in few combinations, with its additive effect prevailing in the mixture with glyphosate for the control of the evaluated species.

Werlang, R.C.; Silva, A.A.

2002-04-01

140

Interação de glyphosate com carfentrazone-ethyl Glyphosate - carfentrazone-ethyl interaction  

Directory of Open Access Journals (Sweden)

Full Text Available Foi conduzido um experimento em condições controladas para determinar a interação do carfentrazone-ethyl em mistura no tanque com o herbicida glyphosate, no controle de seis espécies de plantas daninhas. Glyphosate aplicado isoladamente na dose de 720 g ha-1 foi eficaz no controle de Amaranthus hybridus (100%), Desmodium tortuosum (100%), Bidens pilosa (99%), Eleusine indica (96%), Digitaria horizontalis (100%) e Commelina benghalensis (93%) aos 21 DAA. Carfentrazone-ethyl aplicado isoladamente controlou eficazmente C. benghalensis. As misturas de glyphosate nas doses de 252 e 720 g ha-1 com carfentrazone-ethyl nas doses de 15 e 30 g ha¹ demonstraram efeito aditivo no controle de A. hybridus, D. tortuosum e Bidens pilosa, à exceção das misturas de glyphosate na dose de 252 g ha-1 com as doses de 15 e 30 g ha-1 de carfentrazone-ethyl, que proporcionam efeito sinergístico no controle de D. tortuosum. A adição das duas doses de carfentrazone-ethyl antagonizou o efeito de glyphosate na menor dose (252 g ha-1) no controle de E. indica, apresentando, no entanto, efeito aditivo com o glyphosate na maior dose (720 g ha-1). Já para D. horizontalis, as misturas de carfentrazone-ethyl com glyphosate na menor dose (252 g ha-1) apresentaram efeito sinergístico no controle dessa espécie, demonstrando, ainda, efeito aditivo na mistura com glyphosate na dose de 720 g ha-1. A mistura de carfentrazone-ethyl com glyphosate proporcionou efeito aditivo no controle de C. benghalensis, independentemente das combinações de doses avaliadas. Os resultados deste experimento indicam que carfentrazone-ethyl apresenta comportamento diferenciado quanto à interação com glyphosate, dependendo da espécie de planta daninha e da dose dos herbicidas utilizados na mistura em tanque, sendo complementar na mistura em tanque com glyphosate, pois demonstrou efeito antagônico em poucas das combinações estudadas, prevalecendo seu efeito aditivo na mistura com glyphosate, no controle das espécies avaliadas.Under evironmental controlled conditions experiments were conducted to determine the efficacy of carfentrazone-ethyl in tank mixture with glyphosate to control six weed species. Glyphosate alone at 720 g ha-1 was effective in controlling Amaranthus hybridus (100%), Desmodium tortuosum (100%), Bidens pilosa (99%), Eleusine indica (96%), Digitaria horizontalis (100%) and Commelina benghalensis (93%) at 21 DAA. Carfentrazone-ethyl alone controlled only C. benghalensis. efficiently. Glyphosate mixtures (252 and 720 g ha-1) with carfentrazone-ethyl at 15 and 30 g ha¹ showed an additive effect in controlling A. hybridus, D. tortuosum and Bidens pilosa, except for glyphosate mixture at 252 g ha-1 with carfentrazone-ethyl at 15 and 30 g ha-1, which showed synergism in controlling D. tortuosum. The addition of the two carfentrazone-ethyl doses antagonized the effect of the smallest dose (252 g ha-1) of glyphosate on E. indica control. However, the largest glyphosate dose (720 g ha-1) provided additive effect when mixed with both carfentrazone-ethyl doses. For D. horizontalis, carfentrazone-ethyl mixtures with glyphosate in the smallest dose (252 g ha-1) had a synergistic effect in the control of this species, also showing and additive effect in the mixture with glyphosate at 720 g ha-1. Carfentrazone-ethyl mixture with glyphosate provided an additive effect in C. benghalensis control, regardless of dose combinations. The results of this experiment indicate that carfentrazone-ethyl presents a differentiated behavior when interacting with glyphosate, depending on the weed species and the herbicide dose used in the tank mixtures, being complementary in tank-mix combinations with glyphosate, since it showed an antagonistic effect in few combinations, with its additive effect prevailing in the mixture with glyphosate for the control of the evaluated species.

R.C. Werlang; A.A. Silva

2002-01-01

 
 
 
 
141

Herbicidas alternativos para controle de biótipos de Conyza bonariensis e C. canadensis resistentes ao glyphosate Alternative herbicides to control glyphosate-resistant biotypes of Conyza bonariensis and C. canadensis  

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Full Text Available Após sucessivos anos, aplicações do herbicida glyphosate em pomares de citros no Estado de São Paulo selecionaram biótipos resistentes de Conyza bonariensis e C. canadensis. Na ocorrência de plantas daninhas resistentes em uma área agrícola, tornam-se necessárias mudanças nas práticas de manejo para obtenção de adequado controle das populações resistentes, bem como para a redução da pressão de seleção sobre outras espécies. Assim, este trabalho foi realizado com o objetivo de identificar herbicidas alternativos para controle de biótipos de Conyza spp. resistentes ao herbicida glyphosate, com aplicações em diferentes estádios fenológicos da planta daninha. Três experimentos foram conduzidos em campo, em pomares de citros em formação, sobre plantas de buva em estádio fenológico de dez folhas e no pré-florescimento. Para plantas no estádio de dez folhas, controle satisfatório foi obtido com aplicações de glyphosate + bromacil + diuron (1.440 + 1.200 + 1.200 g ha-1), glyphosate + atrazina (1.440 + 1.500 g ha-1) e glyphosate + diuron (1.440 + 1.500 g ha-1). Quando em estádio de pré-florescimento de Conyza spp., a aplicação do herbicida amônio-glufosinato, na dose de 400 g ha-1, isolado ou associado a MSMA, bromacil+diuron, metsulfuron, carfentrazone e paraquat, foi a alternativa viável para controle dos biótipos resistentes ao glyphosate.After successive years, glyphosate applications on São Paulo-Brazil citrus orchards selected resistant biotypes of Conyza bonariensis and C. canadensis. The occurrence of herbicide-resistant weed biotypes at some agricultural area makes it necessary to change the management practices to reach effective control of the selected resistant populations, as well as to reduce selection pressure on the other species. Thus, this work aimed to identify the alternative herbicides to control glyphosate-resistant biotypes of Conyza spp., with applications at different weed phenological stages. Three trials were developed under field conditions: in citrus orchards under formation, in plants with phenological stages of ten leaves and at pre-flowering. For plants at the ten leaf stage, satisfactory control was reached with applications of glyphosate + bromacil + diuron (1,440 + 1,200 + 1,200 g ha-1), glyphosate + atrazine (1,440 + 1,500 g ha-1) and glyphosate + diuron (1,440 + 1,500 g ha-1). For Conyza spp. plants at the pre-flowering stage, ammonium-glufosinate application, at the rate of 400 g ha-1, isolated or associated to MSMA, bromacil+diuron, metsulfuron, carfentrazone and paraquat, was a viable alternative to control glyphosate-resistant biotypes.

M.S. Moreira; M.S.C. Melo; S.J.P. Carvalho; M. Nicolai; P.J. Crhistoffoleti

2010-01-01

142

Impact of glyphosate on the development, fertility and demography of Chrysoperla externa (Neuroptera: Chrysopidae): ecological approach.  

Science.gov (United States)

Few ecotoxicological studies have used life table analysis to evaluate the toxicity of pesticides on beneficial organisms. This study is the first report of the effect of the herbicide glyphosate on a predator insect, Chrysoperla externa, using a demographic approach. This predator is associated to soybean pests and has a potential role as a biological control agent in the Neotropical Region. The objective of this work was to evaluate the side-effects of glyphosate on the development, fertility and demography of C. externa, treated orally by ingestion of glyphosate-dipped eggs of Sitotroga cerealella in laboratory conditions. The data were analyzed using the age-stage, two-sex life table. Development from third larval instar to pupae and adult longevity were shorter in glyphosate-treatment than in the control. Adult pre-reproductive period was longer in glyphosate-treatment than in the control. Fecundity and fertility were deeply reduced, as well, being fertility greater affected. A high important reduction was registered in all population parameters. Most eggs from glyphosate-treated cohort looked abnormal, smaller than control, dehydrated and became black 2d after oviposition. In addition, adults developed tumours in the abdomen region at 20d after emergence, being the effect more drastic in females than males. It is beyond the scope of our study to speculate on the effects of this herbicide on C. externa field populations. However, it seems likely that populations under continuous use of glyphosate would be exposed at greater detrimental effects in the long term. PMID:19577273

Schneider, M I; Sanchez, N; Pineda, S; Chi, H; Ronco, A

2009-07-03

143

Nanofiltration process of glyphosate simulated wastewater.  

UK PubMed Central (United Kingdom)

Nanofiltration separation of glyphosate simulated wastewater was investigated using a DK membrane. The effects of operating parameters and the addition of impurities on membrane performance were studied in detail. It was found that at 20 °C, with a glyphosate concentration of 500 mg/L and pH of 2.96, the glyphosate retention rate and the membrane permeate flux increased slightly with increasing transmembrane pressure. With an increase in operating temperature, the permeate flux increased linearly while the retention rate decreased. The permeate flux and glyphosate retention rate decreased with increasing feed concentration. Within the pH range of 3-5, the glyphosate retention rate decreases with increasing pH and reaches a minimum at the isoelectric point of the membrane, while the permeate flux reaches a maximum level at this point. In the pH range of 5-11, with the increases of pH, the glyphosate retention rate increases and the permeate flux decreases. Glyphosate retention decreases slightly with increasing NaCl and phosphite concentrations. This can be explained in terms of the shielding phenomenon.

Liu ZY; Xie M; Ni F; Xu YH

2012-01-01

144

Development of an oligopeptide functionalized surface plasmon resonance biosensor for online detection of glyphosate.  

Science.gov (United States)

We report a surface plasmon resonance (SPR) biosensor for online detection of glyphosate. The surface of the sensing element is decorated with an oligopeptide, TPFDLRPSSDTR, which is identified by using phage display library. This oligopeptide shows high binding specificity for glyphosate (KD = 8.6 ?M), probably because of the presence of R and D in the oligopeptide. To detect glyphosate in buffer solution, an SPR gold sensor chip is modified by using the oligopeptide with a surface density of 0.6 1/nm(2). The sensitivity of this oligopeptide-functionalized SPR biosensor is 1.02 RU/?M whereas the limit of detection (LOD) is 0.58 ?M. This oligopeptide functionalized SPR biosensor also shows good specificity against other analytes such as glycine, thiacloprid, and imidacloprid. PMID:23675691

Ding, Xiaokang; Yang, Kun-Lin

2013-05-28

145

Development of an oligopeptide functionalized surface plasmon resonance biosensor for online detection of glyphosate.  

UK PubMed Central (United Kingdom)

We report a surface plasmon resonance (SPR) biosensor for online detection of glyphosate. The surface of the sensing element is decorated with an oligopeptide, TPFDLRPSSDTR, which is identified by using phage display library. This oligopeptide shows high binding specificity for glyphosate (KD = 8.6 ?M), probably because of the presence of R and D in the oligopeptide. To detect glyphosate in buffer solution, an SPR gold sensor chip is modified by using the oligopeptide with a surface density of 0.6 1/nm(2). The sensitivity of this oligopeptide-functionalized SPR biosensor is 1.02 RU/?M whereas the limit of detection (LOD) is 0.58 ?M. This oligopeptide functionalized SPR biosensor also shows good specificity against other analytes such as glycine, thiacloprid, and imidacloprid.

Ding X; Yang KL

2013-06-01

146

Identificação de biótipos de azevém (Lolium multiflorum) resistentes ao herbicida glyphosate em pomares de maçã Identification of glyphosate-resistant ryegrass (Lolium multiflorum) biotypes in apple orchards  

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Full Text Available O glyphosate é um herbicida de amplo espectro utilizado há mais de 15 anos em pomares de maçã na região de Vacaria-RS, para manejo da vegetação nas linhas da cultura. São realizadas, em geral, três a quatro aplicações por ciclo e a dose normalmente utilizada é de 720 a 1.080 g e.a. ha-1 de glyphosate (2 a 3 L ha-1 do produto comercial). O azevém (Lolium multiflorum) é uma planta daninha comum em pomares e, tradicionalmente, sensível ao glyphosate. Entretanto, nos últimos anos a ocorrência de plantas de azevém que, após receberem o tratamento com glyphosate, não manifestam sintomas significativos de toxicidade sugere que elas adquiriram resistência ao produto. Assim, com o objetivo de avaliar a resposta de uma população de plantas de azevém ao glyphosate, foram realizados três experimentos: um em campo e dois em casa de vegetação. No experimento em campo os tratamentos avaliados constaram de doses crescentes de glyphosate (0, 360, 720, 1.440, 2.880, 5.760 e 11.520 g e.a. ha-1), e os herbicidas paraquat, glufosinate, haloxyfop e diclofop foram empregados como produtos-padrão, aplicados em dois estádios vegetativos do azevém. No experimento em casa de vegetação, os tratamentos constaram de doses crescentes de glyphosate (0, 360, 720, 1.440, 2.880 e 5.760 g e.a. ha-1) mais os herbicidas testemunhas, aplicados sobre plantas do biótipo considerado resistente e de um sensível. No segundo experimento realizado em casa de vegetação foram avaliados tratamentos contendo glyphosate (720, 1.440, 2.880, 720 + 720 e 720 + 1.440 g e.a. ha-1), em aplicações únicas e seqüenciais, mais os herbicidas paraquat, glufosinate, haloxyfop, clethodim, sethoxydim, diclofop, fenoxaprop, fluazifop, paraquat + diuron, atrazine + simazine, trifluralin e metolachlor. A toxicidade dos tratamentos herbicidas foi avaliada aos 15, 30 e 45 DAT (dias após tratamento). Os resultados obtidos nos experimentos em campo e em casa de vegetação, de forma geral, evidenciam que o biótipo sensível é facilmente controlado com o herbicida glyphosate e pelos demais herbicidas pós-emergentes avaliados, independentemente do estádio vegetativo. Demonstram, ainda, que o biótipo resistente apresenta-se, igualmente ao biótipo sensível, altamente suscetível aos herbicidas com mecanismo de ação distinto daquele do glyphosate. No entanto, o biótipo resistente apresenta baixa resposta ao herbicida glyphosate, mesmo se este for empregado em altas doses, evidenciando ter adquirido resistência a esse produto.Glyphosate is a wide spectrum herbicide used for over 15 years in apple orchards in Vacaria-RS for weed control in rows of trees. Usually, 3 to 4 applications per year are made at a rate of 720 to 1080 g a.e. glyphosate ha-1 (2 to 3 L ha-1 of commercial product). Ryegrass (Lolium multiflorum) is a common weed in orchards and traditionally sensitive to glyphosate. However, in the last years, some ryegrass plants have not been found to show significant toxicity symptoms after treatment with glyphosate, suggesting that they acquired resistance to this product. To evaluate the response of a ryegrass plant population to glyphosate, one field and two greenhouse experiments were carried out. The field experiment treatments had increasing rates of glyphosate (0; 360; 720; 1,440; 2,880; 5,760 and 11,520 g a.e. ha-1), in addition to the herbicides paraquat, glufosinate-ammonium, haloxyfop and diclofop-methyl as standards, sprayed at two different vegetative growth stages of ryegrass. The greenhouse experiments had increasing rates of glyphosate (0; 360; 720; 1,440; 2,880 and 5,760 g a.e. ha-1) plus the above listed check herbicides sprayed on biotypes considered resistant and on plants of one susceptible biotype. In the second greenhouse experiment, glyphosate rates (720; 1,440; 2,880; 720 + 720 and 720 + 1,440 g a.e. ha-1) were sprayed in single and sequential applications, in addition to the herbicides paraquat, glufosinate-ammonium, haloxyfop, clethodim, sethoxydim, diclofop-methyl, fenoxaprop, fluazifop, paraqua

L. Vargas; E.S. Roman; M.A. Rizzardi; V.C. Silva

2004-01-01

147

Lack of interaction between glyphosate and fungicide treatments on rhizoctonia crown and root rot in glyphosate-resistant sugarbeet  

UK PubMed Central (United Kingdom)

A field experiment was conducted in 2008 and 2009 in the Saginaw Valley region of Michigan to determine if there were potential interactions between applications of glyphosate and the fungicide azoxystrobin and to determine the effectiveness of foliar and in-furrow azoxystrobin applications when Rhizoctonia solani is present. Significant differences in disease indices, percentage of harvestable sugarbeet (Beta vulgaris L.), and percentage of healthy sugarbeet were evident among the different varieties and azoxystrobin treatments, but herbicide treatment did not significantly affect these parameters. Hillesho?g 9027RR and Hillesho?g 9029RR had the lowest disease indices and highest percentage of healthy sugarbeet when compared with Crystal RR827 and Hillesho?g 9028RR. Foliar applied azoxystrobin resulted in the lowest disease index (2.0) and highest percentageof healthy sugarbeet (42%) when compared with the in-furrow application or no fungicide treatment. In-furrow azoxystrobin reduced the disease index when compared with no fungicide. Similar trends were observed for harvestable sugarbeet, except for Crystal RR827 where there was not a significant difference between in-furrow azoxystrobin and no fungicide. Glyphosate did not affect the efficacy of fungicide treatments, but choosing a Rhizoctonia-tolerant variety and applying foliar fungicide applications appear to be the best methods for managing Rhizoctonia crown and root rot in glyphosate-resistant sugarbeet.

Barnett KellyA; Sprague ChristyL; Kirk WilliamW; Hanson LindaE

2011-01-01

148

Monitoring glyphosate and AMPA concentrations in wells and drains using the sorbicell passive sampler  

DEFF Research Database (Denmark)

Glyphosate is one of the world’s most extensively used weed control agents. Glyphosate, and its metabolite aminomethylphosphonic acid (AMPA), are suspected to be hazardous to human health and the aquatic environment. In Denmark, the extensive use has resulted in an increasing number of occurrences in groundwater wells and tile drains, stressing the need for extensive monitoring of this compound in the environment. Traditionally, monitoring programs are based on grab sampling which is time consuming and expensive due to the need for frequent sampling events. Using a passive sampling device, the SorbiCell, will decrease the workload and number of samples freeing up funds for larger monitoring programs. When installed in a well the SorbiCell will continuously sample the water giving either a flux-weighed or time-weighted average measurement of the glyphosate/AMPA concentration throughout the sampling period. It may therefore be possible to measure lower concentrations as the glyphosate/AMPA sorbed in the SorbiCell is an accumulated measurement. Also, glyphosate/AMPA associated with sudden flush events will be detected by the SorbiCells, while such events may pass between two consecutive grab samples. To document the ability of the SorbiCell to capture glyphosate/AMPA, a series of laboratory flow experiments were carried out. Sorption and release from the flow cells is tested with two influent solutions (0.15 µg/l and 5 µg/l), one of demineralized water and the other with drain water from the Silstrup site (part of the Danish Pesticide Leaching Assessment Program, PLAP), spiked with 14C marked glyphosate. Two different volumes of effluent were then eluted through Sorbicell’s with two different capacities. The concentration of glyphosate/AMPA was continuously measured in both the influent and effluent. The aim of the study is to test and verify if the glyphosate/AMPA sensitive SorbiCell is an efficient and reliable, and cost-effective technology for groundwater and drainwater monitoring of pesticides.

Vendelboe, Anders Lindblad; de Jonge, Hubert

149

Bioassay and Characterization of Several Palmer Amaranth (Amaranthus palmeri) Biotypes with Varying Tolerances to Glyphosate  

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Full Text Available The wide distribution of Palmer amaranth (Amaranthus palmeri) in the southern US became a serious weed control problem prior to the extensive use of glyphosate-resistant crops. Currently glyphosate-resistant populations of Palmer amaranth occur in many areas of this geographic region creating an even more serious threat to crop production. Investigations were undertaken using four biotypes (one glyphosate-sensitive, one resistant from Georgia and two of unknown tolerance from Mississippi) of Palmer amaranth to assess bioassay techniques for the rapid detection and level of resistance in populations of this weed. These plants were characterized with respect to chlorophyll, betalain, and protein levels and immunological responses to an antibody of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) the target site of glyphosate. Only slight differences were found in four biotypes grown under greenhouse conditions regarding extractable soluble protein and chlorophyll content, but one biotype was found to be devoid of the red pigment, betalain. Measurement of early growth (seedling shoot elongation) of seedlings was a useful detection tool to determine glyphosate resistance. A leaf disc bioassay (using visual ratings and/or chlorophyll analysis) and an assay for shikimate accumulation were effective methods for determining herbicide resistance levels. The two unknown biotypes were found to be resistant to this herbicide. Some differences were found in the protein profiles of the biotypes, and western blots demonstrated a weak labeling of antibody in the glyphosate-sensitive biotype, whereas strong labeling occurred in the resistant plants. This latter point supports research by others, that increased copy number of the EPSPS gene (and increased EPSPS protein levels) is the resistance mechanism in this species. Results indicate the utility of certain bioassays for the determination of resistance and provide useful comparative information on the levels of inherent constituents among closely related plants.

Robert E. Hoagland; Robin H. Jordan; Neal D. Teaster

2013-01-01

150

Associações entre o herbicida glyphosate e inseticidas na cultura da soja Roundup Ready® Associations among glyphosate and insecticides in Roundup Ready® soybean  

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Full Text Available Este trabalho teve o objetivo de avaliar os efeitos da associação do herbicida glyphosate com 10 inseticidas de diferentes grupos químicos sobre a cultura da soja Roundup Ready® (cultivar Monsoy 8585 RR®), o controle de plantas daninhas e o controle da lagarta-da-soja (Anticarsia gemmatalis). O experimento foi realizado em lavoura no município de Nova Xavantina - MT, no período de novembro de 2005 a abril de 2006, em solo classificado como Latossolo Vermelho distrófico. O delineamento experimental utilizado foi o de blocos ao acaso, em esquema fatorial 11 x 2, sendo os fatores constituídos por 11 tratamentos inseticidas [lambdacyhalothrin (3,75 g ha-1); permethrin (12,50 g ha-1); methamidophos (300,00 g ha-1); chlorpyriphos (240,00 g ha-1); acephate (150,00 g ha-1); endosulfan (175,00 g ha-1); methomyl (107,50 g ha-1); lufenuron (7,50 g ha-1); triflumuron (14,40 g ha-1); spinosad (24,00 g ha-1); e testemunha sem inseticida], com ou sem a adição (mistura em tanque) de 960 g e.a. ha-1 de glyphosate, formando 22 tratamentos, conduzidos em quatro repetições. Os tratamentos foram aplicados 30 dias depois da emergência da cultura. A mistura do herbicida glyphosate com o inseticida chlorpyriphos causou fitotoxicidade inicial à cultura da soja RR®. O controle das plantas daninhas Chamaesyce hirta, Alternanthera tenella, Euphorbia heterophylla e Cenchrus echinatus não foi afetado pelas misturas de glyphosate com todos os inseticidas avaliados. A adição do glyphosate à calda de aplicação prejudicou a eficiência inicial dos inseticidas methomyl, methamidophos, chlorpyriphos e acephate no controle de Anticarsia gemmatalis, porém incrementou o controle dessa praga quando associado aos inseticidas spinosad, lambdacyhalothrin e lufenuron. A combinação de glyphosate com os inseticidas methamidophos, chlorpyriphos, lufenuron, triflumuron e spinosad proporcionou os maiores níveis de produtividade de grãos da soja RR®.This research aimed to evaluate the effects of the association of the herbicide glyphosate with 10 different insecticides of several chemical groups on Roundup Ready® soybean (Monsoy 8585 RR®), weeds, and on velvetbean caterpillar (Anticarsia gemmatalis). The experiment was carried out under field conditions at Nova Xavantina-MT, from November 2005 to April 2006 in soil classified as Dystrophic Red Latosol. Trial design was a factorial randomized complete block having 11 insecticide treatments: [lambdacyhalothrin (3,75 g ha-1); permethrin (12,50 g ha-1); methamidophos (300,00 g ha-1); chlorpyriphos (240,00 g ha-1); acephate (150,00 g ha-1); endosulfan (175,00 g ha-1); methomyl (107,50 g ha-1); lufenuron (7,50 g ha-1); triflumuron (14,40 g ha-1); spinosad (24,00 g ha-1); and untreated without insecticide] with and without addiction (tank mixture) of 960 g a.e. ha-1 of glyphosate, totalling 22 treatments. Each treatment had four replications. Treatments were applied 30 days after soybean emergence. Tank mixture of glyphosate and insecticide caused phytotoxicity to soybean. The control of the weeds Chamaesyce hirta, Alternathera tenella, Euphorbia heterophylla and Cenchrus echinatus was not affected by the glyphosate mixture. Tank mixture of glyphosate with the insecticides methomyl, methamidophos, chlorpyriphos and acephate reduced their control of Anticarsia gemmatalis. However, the control performance of the insecticides spinosad, lambdacyhalothrin and lufenuron was increased. The combination of glyphosate with the insecticides methamidophos, chlorpyriphos, lufenuron, triflumuron and spinosad provided the highest soybean yields.

F.A. Petter; S.O. Procópio; A. Cargnelutti Filho; A.L.L. Barroso; L.P. Pacheco; A.F. Bueno

2007-01-01

151

Associações entre o herbicida glyphosate e inseticidas na cultura da soja Roundup Ready®/ Associations among glyphosate and insecticides in Roundup Ready® soybean  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Este trabalho teve o objetivo de avaliar os efeitos da associação do herbicida glyphosate com 10 inseticidas de diferentes grupos químicos sobre a cultura da soja Roundup Ready® (cultivar Monsoy 8585 RR®), o controle de plantas daninhas e o controle da lagarta-da-soja (Anticarsia gemmatalis). O experimento foi realizado em lavoura no município de Nova Xavantina - MT, no período de novembro de 2005 a abril de 2006, em solo classificado como Latossolo Vermelho distr? (more) ?fico. O delineamento experimental utilizado foi o de blocos ao acaso, em esquema fatorial 11 x 2, sendo os fatores constituídos por 11 tratamentos inseticidas [lambdacyhalothrin (3,75 g ha-1); permethrin (12,50 g ha-1); methamidophos (300,00 g ha-1); chlorpyriphos (240,00 g ha-1); acephate (150,00 g ha-1); endosulfan (175,00 g ha-1); methomyl (107,50 g ha-1); lufenuron (7,50 g ha-1); triflumuron (14,40 g ha-1); spinosad (24,00 g ha-1); e testemunha sem inseticida], com ou sem a adição (mistura em tanque) de 960 g e.a. ha-1 de glyphosate, formando 22 tratamentos, conduzidos em quatro repetições. Os tratamentos foram aplicados 30 dias depois da emergência da cultura. A mistura do herbicida glyphosate com o inseticida chlorpyriphos causou fitotoxicidade inicial à cultura da soja RR®. O controle das plantas daninhas Chamaesyce hirta, Alternanthera tenella, Euphorbia heterophylla e Cenchrus echinatus não foi afetado pelas misturas de glyphosate com todos os inseticidas avaliados. A adição do glyphosate à calda de aplicação prejudicou a eficiência inicial dos inseticidas methomyl, methamidophos, chlorpyriphos e acephate no controle de Anticarsia gemmatalis, porém incrementou o controle dessa praga quando associado aos inseticidas spinosad, lambdacyhalothrin e lufenuron. A combinação de glyphosate com os inseticidas methamidophos, chlorpyriphos, lufenuron, triflumuron e spinosad proporcionou os maiores níveis de produtividade de grãos da soja RR®. Abstract in english This research aimed to evaluate the effects of the association of the herbicide glyphosate with 10 different insecticides of several chemical groups on Roundup Ready® soybean (Monsoy 8585 RR®), weeds, and on velvetbean caterpillar (Anticarsia gemmatalis). The experiment was carried out under field conditions at Nova Xavantina-MT, from November 2005 to April 2006 in soil classified as Dystrophic Red Latosol. Trial design was a factorial randomized complete block having 1 (more) 1 insecticide treatments: [lambdacyhalothrin (3,75 g ha-1); permethrin (12,50 g ha-1); methamidophos (300,00 g ha-1); chlorpyriphos (240,00 g ha-1); acephate (150,00 g ha-1); endosulfan (175,00 g ha-1); methomyl (107,50 g ha-1); lufenuron (7,50 g ha-1); triflumuron (14,40 g ha-1); spinosad (24,00 g ha-1); and untreated without insecticide] with and without addiction (tank mixture) of 960 g a.e. ha-1 of glyphosate, totalling 22 treatments. Each treatment had four replications. Treatments were applied 30 days after soybean emergence. Tank mixture of glyphosate and insecticide caused phytotoxicity to soybean. The control of the weeds Chamaesyce hirta, Alternathera tenella, Euphorbia heterophylla and Cenchrus echinatus was not affected by the glyphosate mixture. Tank mixture of glyphosate with the insecticides methomyl, methamidophos, chlorpyriphos and acephate reduced their control of Anticarsia gemmatalis. However, the control performance of the insecticides spinosad, lambdacyhalothrin and lufenuron was increased. The combination of glyphosate with the insecticides methamidophos, chlorpyriphos, lufenuron, triflumuron and spinosad provided the highest soybean yields.

Petter, F.A.; Procópio, S.O.; Cargnelutti Filho, A.; Barroso, A.L.L.; Pacheco, L.P.; Bueno, A.F.

2007-01-01

152

Influence of glyphosate on the copper dissolution in phosphate buffer  

Science.gov (United States)

The electrochemical behavior of copper microelectrode in phosphate buffer in the presence of glyphosate was investigated by electrochemical techniques. It was observed that the additions of glyphosate in the phosphate buffer increased the anodic current of copper microelectrode and the electrochemical dissolution was observed. This phenomenon could be associated with the Cu(II) complexation by glyphosate forming a soluble complex. Physical characterization of the surface showed that, in absence of glyphosate, an insoluble layer covered the copper surface; on the other hand, in presence of glyphosate, it was observed a corroded copper surface with the formation of glyphosate complex in solution.

Coutinho, C. F. B.; Silva, M. O.; Machado, S. A. S.; Mazo, L. H.

2007-01-01

153

Leaf anatomy and morphometry in three eucalypt clones treated with glyphosate/ Anatomia e morfometria foliar em clones de eucalipto tratados com glyphosate  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Este trabalho teve como objetivo avaliar os efeitos da deriva simulada de glyphosate na morfoanatomia de três clones de eucalipto e correlacionar os sintomas de intoxicação em escala microscópica com aqueles observados à vista desarmada. Os efeitos da deriva do glyphosate foram proporcionais às doses testadas, sendo Eucalyptus urophylla mais tolerante ao herbicida que E. grandis e o híbrido urograndis. Os sintomas de intoxicação foram semelhantes para os diferent (more) es clones testados, tanto aos 7 quanto aos 15 dias após a aplicação, sendo caracterizados, morfologicamente, por murcha, clorose e enrolamento foliar e, no caso das maiores doses, por necrose, senescência foliar e morte das plantas de eucalipto. Anatomicamente, doses de glyphosate superiores a 86,4 g.ha-1 provocaram plasmólise, hipertrofia e hiperplasia celular, formação de tecido de cicatrização e morte das células da face adaxial da epiderme. Observou-se diminuição na espessura do parênquima lacunoso e aumento na espessura do parênquima paliçádico e da lâmina foliar. O aumento na espessura da folha e do parênquima paliçádico podem estar relacionados à resposta das plantas ao glyphosate, como forma de compensar a área fotossinteticamente reduzida pelas necroses e senescência causadas pelo herbicida. Abstract in english This work aimed to evaluate the effects of simulated drift of glyphosate on the morphoanatomy of three eucalypt clones and to correlate the intoxication symptoms on a microscopic scale with those observed in this visual analysis. The effects of glyphosate drift were proportional to the five doses tested, with Eucalyptus urophylla being more tolerant to the herbicide than E. grandis and urograndis hybrid. The symptoms of intoxication which were similar for the different cl (more) ones at 7 and 15 days after application were characterized by leaf wilting, chlorosis and curling and, at the highest rates, by necrosis, leaf senescence and death. Anatomically glyphosate doses higher than 86.4 g.ha-1 caused cellular plasmolysis, hypertrophy and hyperplasia, formation of the cicatrization tissue and dead cells on the adaxial epidermis. The spongy parenchyma had a decrease, and the palisade parenchyma and leaf blade thickness had an increase. The increased thickness in leaf blade and palisade parenchyma may be related to the plant response to glyphosate action, as a form of recovering the photosynthetically active area reduced by necroses and leaf senescence caused by the herbicide.

Tuffi Santos, LD.; Sant'Anna-Santos, BF.; Meira, RMSA.; Ferreira, FA.; Tiburcio, RAS.; Machado, AFL.

2009-02-01

154

Effect of glyphosate application timings and methods on glyphosate-resistant cotton  

Science.gov (United States)

Under certain conditions, application of glyphosate to glyphosate-resistant (GR) cotton can lead to fruit shedding and yield reductions. Field studies were conducted at the Texas Agricultural Experiment Station using GR cotton, cv. ‘DeltaPine 5690RR’, to determine if application method and timing af...

155

Review of genotoxicity studies of glyphosate and glyphosate-based formulations.  

Science.gov (United States)

An earlier review of the toxicity of glyphosate and the original Roundup™-branded formulation concluded that neither glyphosate nor the formulation poses a risk for the production of heritable/somatic mutations in humans. The present review of subsequent genotoxicity publications and regulatory studies of glyphosate and glyphosate-based formulations (GBFs) incorporates all of the findings into a weight of evidence for genotoxicity. An overwhelming preponderance of negative results in well-conducted bacterial reversion and in vivo mammalian micronucleus and chromosomal aberration assays indicates that glyphosate and typical GBFs are not genotoxic in these core assays. Negative results for in vitro gene mutation and a majority of negative results for chromosomal effect assays in mammalian cells add to the weight of evidence that glyphosate is not typically genotoxic for these endpoints in mammalian systems. Mixed results were observed for micronucleus assays of GBFs in non-mammalian systems. Reports of positive results for DNA damage endpoints indicate that glyphosate and GBFs tend to elicit DNA damage effects at high or toxic dose levels, but the data suggest that this is due to cytotoxicity rather than DNA interaction with GBF activity perhaps associated with the surfactants present in many GBFs. Glyphosate and typical GBFs do not appear to present significant genotoxic risk under normal conditions of human or environmental exposures. PMID:23480780

Kier, Larry D; Kirkland, David J

2013-03-12

156

Review of genotoxicity studies of glyphosate and glyphosate-based formulations.  

UK PubMed Central (United Kingdom)

An earlier review of the toxicity of glyphosate and the original Roundup™-branded formulation concluded that neither glyphosate nor the formulation poses a risk for the production of heritable/somatic mutations in humans. The present review of subsequent genotoxicity publications and regulatory studies of glyphosate and glyphosate-based formulations (GBFs) incorporates all of the findings into a weight of evidence for genotoxicity. An overwhelming preponderance of negative results in well-conducted bacterial reversion and in vivo mammalian micronucleus and chromosomal aberration assays indicates that glyphosate and typical GBFs are not genotoxic in these core assays. Negative results for in vitro gene mutation and a majority of negative results for chromosomal effect assays in mammalian cells add to the weight of evidence that glyphosate is not typically genotoxic for these endpoints in mammalian systems. Mixed results were observed for micronucleus assays of GBFs in non-mammalian systems. Reports of positive results for DNA damage endpoints indicate that glyphosate and GBFs tend to elicit DNA damage effects at high or toxic dose levels, but the data suggest that this is due to cytotoxicity rather than DNA interaction with GBF activity perhaps associated with the surfactants present in many GBFs. Glyphosate and typical GBFs do not appear to present significant genotoxic risk under normal conditions of human or environmental exposures.

Kier LD; Kirkland DJ

2013-04-01

157

Alteração das características biológicas dos biótipos de azevém (Lolium multiflorum) ocasionada pela resistência ao herbicida glyphosate Change in the biological characteristics of ryegrass (Lolium multiflorum) biotypes caused by resistance to the herbicide glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available A resistência de biótipos de azevém ao herbicida glyphosate está alterando o manejo da vegetação de cobertura do solo em pomares de maçã. O objetivo deste trabalho foi determinar a dose de glyphosate necessária para reduzir 50% do acúmulo de matéria seca (GR50), a resposta do biótipo resistente e sensível a herbicidas graminicidas e o acúmulo de matéria seca destes biótipos durante o ciclo. Para isso, foram conduzidos três experimentos. No primeiro, os tratamentos constaram de doses crescentes de glyphosate aplicadas sobre plantas dos biótipos resistente e sensível para determinar o GR50. No segundo experimento, os tratamentos constaram de doses dos herbicidas glyphosate, haloxyfop-r, diclofop, fluazifop-p, fenoxaprop-p e paraquat. No terceiro experimento, sementes dos biótipos resistente e sensível foram semeadas em recipientes com capacidade para 10 L e as plantas originadas delas foram colhidas quinzenalmente, para determinação da matéria seca da parte aérea, radicular e total. Como resultados, foi obtido GR50 de 287,5 e de 4.833,5 g e.a. ha-1 de glyphosate para os biótipos sensível e resistente, respectivamente, e verificou-se que existem diferenças significativas na resposta dos biótipos aos herbicidas graminicidas, dependendo da dose utilizada. Além disso, o biótipo sensível evidenciou maior capacidade de acúmulo de matéria seca e produção de sementes. Constatouse, assim, fator de resistência (FR) de 16,8 e que o mecanismo de resistência provoca alterações nas características biológicas do biótipo resistente e afeta a sensibilidade deste aos herbicidas graminicidas.The identification of ryegrass biotypes resistant to glyphosate is causing changes in weed management in apple orchards. Three experiments were carried out to determine the GR50 of the biotypes, to grass herbicides and dry matter accumulation. The first experiment tested different rates of glyphosate. Their effects on GR50 dry matter accumulation by the biotype were assessed. In the second experiment different rates of glyphosate and grass herbicides were tested: glyphosate, haloxyfop-r, diclofop, fluazifop-p, fenoxaprop-p and paraquat. A third experiments was carried out under glasshouse conditions to determine the curve of dry matter accumulation. The results showed GR50 of 287.5 and 4,833.5 g e. a. ha-1 of glyphosate for the sensitive and resistant biotypes, respectively. The results showed that the resistant factor (RF) was 16.8 and that the resistance mechanism alters the biological characteristics of the resistant biotype affecting its sensitivity to grass herbicides.

L. Vargas; E.S. Roman; M.A. Rizzardi; V.C. Silva

2005-01-01

158

Improved method for preparing glyphosate by catalytic oxidation of N-(phosphonomethyl) iminodiacetic acid through oxygen-rich gas  

UK PubMed Central (United Kingdom)

The invention provides an improved method for preparing glyphosate by catalytically oxidizing N-(phosphonomethyl) iminodiacetic acid with oxygen-rich gas. The method comprises the following steps: selecting N-(phosphonomethyl) iminodiacetic acid (PMIDA) as the raw material, active carbon as a catalyst, and an oxygen-rich gas as an oxidant, adding N-(phosphonomethyl) iminodiacetic acid, the active carbon and water into a high-pressure reaction kettle at a certain ratio, introducing the oxygen-rich gas to carry out oxidation reaction, adding filter cake after the oxidation reaction into a saturated glyphosate solution to fully dissolve glyphosate crystals as much as possible, and filtering while the solution is hot to obtain glyphosate. The method can improve the solubility of glyphosate and further improve the yield of the dry product, and can solve the bumping problem existing in the active carbon separation process at high temperature, thereby improving the safety of the production and effectively separating glyphosate and the active carbon. The method has the advantages of simple operation, easy recovery and utilization of the catalyst, reduced energy consumption, environmental protection, low production cost, etc.

WEI WANG; SHUGUANG ZHOU; JIANNIAN WU; XU YANG; SHUO WANG; JING CHEN

159

Evaluation of the performance of the reduced local lymph node assay for skin sensitization testing.  

Science.gov (United States)

The local lymph node assay (LLNA) is the preferred method for classification of sensitizers within REACH. To reduce the number of mice for the identification of sensitizers the reduced LLNA was proposed, which uses only the high dose group of the LLNA. To evaluate the performance of this method for classification, LLNA data from REACH registrations were used and classification based on all dose groups was compared to classification based on the high dose group. We confirmed previous examinations of the reduced LLNA showing that this method is less sensitive compared to the LLNA. The reduced LLNA misclassified 3.3% of the sensitizers identified in the LLNA and misclassification occurred in all potency classes and that there was no clear association with irritant properties. It is therefore not possible to predict beforehand which substances might be misclassified. Another limitation of the reduced LLNA is that skin sensitizing potency cannot be assessed. For these reasons, it is not recommended to use the reduced LLNA as a stand-alone assay for skin sensitization testing within REACH. In the future, the reduced LLNA might be of added value in a weight of evidence approach to confirm negative results obtained with non-animal approaches. PMID:23459101

Ezendam, Janine; Muller, Andre; Hakkert, Betty C; van Loveren, Henk

2013-02-28

160

Evaluation of the performance of the reduced local lymph node assay for skin sensitization testing.  

UK PubMed Central (United Kingdom)

The local lymph node assay (LLNA) is the preferred method for classification of sensitizers within REACH. To reduce the number of mice for the identification of sensitizers the reduced LLNA was proposed, which uses only the high dose group of the LLNA. To evaluate the performance of this method for classification, LLNA data from REACH registrations were used and classification based on all dose groups was compared to classification based on the high dose group. We confirmed previous examinations of the reduced LLNA showing that this method is less sensitive compared to the LLNA. The reduced LLNA misclassified 3.3% of the sensitizers identified in the LLNA and misclassification occurred in all potency classes and that there was no clear association with irritant properties. It is therefore not possible to predict beforehand which substances might be misclassified. Another limitation of the reduced LLNA is that skin sensitizing potency cannot be assessed. For these reasons, it is not recommended to use the reduced LLNA as a stand-alone assay for skin sensitization testing within REACH. In the future, the reduced LLNA might be of added value in a weight of evidence approach to confirm negative results obtained with non-animal approaches.

Ezendam J; Muller A; Hakkert BC; van Loveren H

2013-06-01

 
 
 
 
161

Dessecação de plantas daninhas com glyphosate em mistura com ureia ou sulfato de amônio/ Weed desiccation with glyphosate mixed with urea or ammonium sulfate  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O glyphosate é um herbicida não-seletivo, sistêmico, usado para controle de plantas daninhas anuais e perenes em todo o mundo. A absorção da molécula do glyphosate ocorre pelos tecidos fotossinteticamente ativos das plantas, porém alguns fatores podem reduzir sua eficácia, como a morfologia e diversidade de espécies, chuva após aplicação, qualidade da água e misturas em tanque com outros defensivos, entre outros. Objetivou-se com este trabalho avaliar a influ (more) ência da adição de sulfato de amônio ou ureia em calda na eficácia do herbicida glyphosate para dessecação de plantas daninhas. Dois experimentos foram desenvolvidos em Piracicaba - SP, com aplicações de glyphosate (720 e 1.440 g ha-1) isolado ou combinado com duas doses de sulfato de amônio (7,5 e 15,0 g L-1) ou ureia (2,5 e 5,0 g L-1) sobre as plantas daninhas: apaga-fogo (Alternanthera tenella) e capim-massambará (Sorghum halepense). Para a espécie menos suscetível ao herbicida (capim-massambará), a adição de fontes nitrogenadas à menor dose de glyphosate acelerou a morte das plantas, elevando os níveis de controle em até 7,3% na avaliação de 21 dias após aplicação (DAA) dos tratamentos. Contudo, os efeitos não foram observados nas avaliações de controle, massa fresca e seca, conduzidas aos 28 DAA. A dose recomendada de glyphosate para cada espécie proporcionou controle satisfatório, sem a necessidade de adição de sulfato de amônio ou ureia. Abstract in english Glyphosate is a non-selective systemic herbicide used to control annual and perennial weeds worldwide. Molecule absorption occurs through the plant's photosynthetically-active tissues; however, some factors might reduce its efficacy, such as morphology and specific diversity, rain after application, water quality and tank mixtures with other chemicals. Thus, this work aimed to evaluate the influence of ammonium sulfate or urea addiction to spray tank on glyphosate efficac (more) y for weed desiccation. Two trials were carried out in Piracicaba - SP, with applications of glyphosate (720 and 1440 g ha-1) alone or combined with two rates of ammonium sulfate (7.5 and 15.0 g L-1) or urea (2.5 and 5.0 g L-1), over the weeds Alternanthera tenella and Sorghum halepense. For the least susceptible species (S. halepense), the addition of nitrogen sources to the lower rate of glyphosate accelerated plant death, increasing the control levels up to 7.3%, at 21 days after application (DAA). However, the effects were not observed when control, fresh and dry mass were evaluated at 28 DAA. Glyphosate recommended rate for each species promoted appropriate control, without the need to add ammonium sulfate or urea.

Carvalho, S.J.P.; Damin, V.; Dias, A.C.R.; Melo, M.S.C.; Nicolai, M.; Christoffoleti, P.J.

2009-06-01

162

Severe adverse effects related to dermal exposure to a glyphosate-surfactant herbicide.  

Science.gov (United States)

This is a case of severe chemical burns following prolonged accidental exposure to a glyphosate-surfactant herbicide. The patient developed local swelling, bullae and exuding wounds. Neurological impairment followed affecting finger flexion and sensation with reduced nerve conduction. Imaging revealed oedema of the soft tissue and juxta-articular osteopenia, and a causal relationship to exposure is suggested. PMID:23360343

Mariager, T P; Madsen, P V; Ebbehøj, N E; Schmidt, B; Juhl, A

2013-01-30

163

Severe adverse effects related to dermal exposure to a glyphosate-surfactant herbicide  

DEFF Research Database (Denmark)

This is a case of severe chemical burns following prolonged accidental exposure to a glyphosate-surfactant herbicide. The patient developed local swelling, bullae and exuding wounds. Neurological impairment followed affecting finger flexion and sensation with reduced nerve conduction. Imaging revealed oedema of the soft tissue and juxta-articular osteopenia, and a causal relationship to exposure is suggested.

Mariager, T P; Madsen, P V

2013-01-01

164

Gene amplification confers glyphosate resistance in Amaranthus palmeri  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The herbicide glyphosate became widely used in the United States and other parts of the world after the commercialization of glyphosate-resistant crops. These crops have constitutive overexpression of a glyphosate-insensitive form of the herbicide target site gene, 5-enolpyruvylshikimate-3-phosphate...

Gaines, Todd A.; Zhang, Wenli; Wang, Dafu; Bukun, Bekir; Chisholm, Stephen T.; Shaner, Dale L.; Nissen, Scott J.

165

Glyphosate Exposure in a Farmer’s Family  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We tested the presence of glyphosate in the urines of a farmer who sprayed a glyphosate based herbicide on his land, and in his family, as his children were born with birth defects that could be due to or promoted by pesticides. Glyphosate residues were measured in urines a day before, during, and t...

Robin Mesnage; Christian Moesch; Rozenn Le Grand Grand; Guillaume Lauthier; Joël Spiroux de Vendômois; Steeve Gress

166

Methods for making plants tolerant to glyphosate and compositions thereof  

UK PubMed Central (United Kingdom)

The methods and materials disclosed herein are directed to glyphosate herbicide tolerance in plants. In particular, the isolation of a glyphosate resistant EPSP synthase coding sequence and its regulatory elements from Eleusine indica. The coding sequence and regulatory sequences are useful to genetically engineer plants for tolerance to glyphosate herbicide.

Baerson Scott R.; Heck Gregory J.; Rodriguez Damian J.

167

METHODS FOR MAKING PLANTS TOLERANT TO GLYPHOSATE AND COMPOSITIONS THEREOF  

UK PubMed Central (United Kingdom)

The methods and materials disclosed herein are directed to glyphosate herbicide tolerance in plants. In particular, the isolation of a glyphosate resistant EPSP synthase coding sequence and its regulatory elements from Eleusine indica. The coding sequence and regulatory sequences are useful to genetically engineer plants for tolerance to glyphosate herbicide.

BAERSON Scott R.; HECK Gregory J.; RODRIGUEZ Damian J.

168

Glyphosate translocation in herbicide tolerant plants/ Translocação do glyphosate em plantas tolerantes ao herbicida  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Objetivou-se neste estudo avaliar a translocação de glyphosate em plantas tolerantes (Ipomoea nil, Tridax procumbens e Spermacoce latifolia) e suscetível (Bidens pilosa) a esse herbicida. As avaliações de absorção e translocação do 14C-glyphosate em I. nil e B. pilosa foram efetuadas às 6, 12, 36 e 72 horas após a aplicação do herbicida (HAT), e em T. procumbens e S. latifolia, às 72 HAT. As plantas foram coletadas e fracionadas em: folha de aplicação, dem (more) ais folhas, caules e raízes; em T. procumbens e S. latifolia, avaliou-se a presença do produto na inflorescência da planta. Em S. latifolia, aproximadamente 88% do glyphosate permaneceu na folha de aplicação, e pequena quantidade translocou para as raízes. Todavia, em T. procumbens, 75% do herbicida permaneceu na folha que recebeu a aplicação, observando-se maior translocação na inflorescência em relação às raízes. Conclui-se que a menor translocação do glyphosate observada em S. latifolia e T. procumbens pode ser um dos fatores responsáveis pela maior tolerância dessas espécies ao herbicida, ao passo que em I. nil a metabolização, a exsudação radicular ou a compartimentalização podem favorecer a tolerância, já que grande quantidade do produto atingiu as raízes da espécie. Abstract in english The objective of this study was to evaluate glyphosate translocation in glyphosate-tolerant weed species (I. nil, T. procumbens and S. latifolia) compared to glyphosate-susceptible species (B. pilosa). The evaluations of 14C-glyphosate absorption and translocation were performed at 6, 12, 36 and 72 hours after treatment (HAT) in I. nil and B. pilosa, and only at 72 HAT in the species T. procumbens and S. latifolia. The plants were collected and fractionated into applicati (more) on leaf, other leaves, stems, and roots. In S. latifolia, approximately 88% of the glyphosate remained in the application leaf and a small amount was translocated to roots at 72 HAT. However, 75% of the herbicide applied on T. procumbens remained in the leaf that had received the treatment, with greater glyphosate translocation to the floral bud. It was concluded that the smaller amount of glyphosate observed in S. latifolia and T. procumbens may partly account for their higher tolerance to glyphosate. However, I. nil tolerance to glyphosate may be associated with other factors such as metabolization, root exudation or compartmentalization, because a large amount of the herbicide reached the roots of this species.

Galon, L; Ferreira, E.A; Aspiazú, I; Concenço, G; Silva, A.F; Silva, A.A; Vargas, L

2013-03-01

169

Glyphosate translocation in herbicide tolerant plants Translocação do glyphosate em plantas tolerantes ao herbicida  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this study was to evaluate glyphosate translocation in glyphosate-tolerant weed species (I. nil, T. procumbens and S. latifolia) compared to glyphosate-susceptible species (B. pilosa). The evaluations of 14C-glyphosate absorption and translocation were performed at 6, 12, 36 and 72 hours after treatment (HAT) in I. nil and B. pilosa, and only at 72 HAT in the species T. procumbens and S. latifolia. The plants were collected and fractionated into application leaf, other leaves, stems, and roots. In S. latifolia, approximately 88% of the glyphosate remained in the application leaf and a small amount was translocated to roots at 72 HAT. However, 75% of the herbicide applied on T. procumbens remained in the leaf that had received the treatment, with greater glyphosate translocation to the floral bud. It was concluded that the smaller amount of glyphosate observed in S. latifolia and T. procumbens may partly account for their higher tolerance to glyphosate. However, I. nil tolerance to glyphosate may be associated with other factors such as metabolization, root exudation or compartmentalization, because a large amount of the herbicide reached the roots of this species.Objetivou-se neste estudo avaliar a translocação de glyphosate em plantas tolerantes (Ipomoea nil, Tridax procumbens e Spermacoce latifolia) e suscetível (Bidens pilosa) a esse herbicida. As avaliações de absorção e translocação do 14C-glyphosate em I. nil e B. pilosa foram efetuadas às 6, 12, 36 e 72 horas após a aplicação do herbicida (HAT), e em T. procumbens e S. latifolia, às 72 HAT. As plantas foram coletadas e fracionadas em: folha de aplicação, demais folhas, caules e raízes; em T. procumbens e S. latifolia, avaliou-se a presença do produto na inflorescência da planta. Em S. latifolia, aproximadamente 88% do glyphosate permaneceu na folha de aplicação, e pequena quantidade translocou para as raízes. Todavia, em T. procumbens, 75% do herbicida permaneceu na folha que recebeu a aplicação, observando-se maior translocação na inflorescência em relação às raízes. Conclui-se que a menor translocação do glyphosate observada em S. latifolia e T. procumbens pode ser um dos fatores responsáveis pela maior tolerância dessas espécies ao herbicida, ao passo que em I. nil a metabolização, a exsudação radicular ou a compartimentalização podem favorecer a tolerância, já que grande quantidade do produto atingiu as raízes da espécie.

L Galon; E.A Ferreira; I Aspiazú; G Concenço; A.F Silva; A.A Silva; L Vargas

2013-01-01

170

Bermudagrass (Cynodon spp) dose-response relationships with clethodim, glufosinate and glyphosate.  

Science.gov (United States)

Greenhouse studies were conducted to evaluate the sensitivity of three commercial cultivars, eight experimental cultivars and common bermudagrass to clethodim, glufosinate and glyphosate. Each herbicide was applied at eight doses. Data were regressed on herbicide dose using a log-logistic curve (R2 = 0.56-0.95 for clethodim, R2 = 0.60-0.94 for glufosinate, and R2 = 0.70-0.96 for glyphosate). The herbicide rate that elicited a 50% plant response (I50) in the bermudagrass cultivars ranged from 0.04 to 0.19 kg ha(-1) clethodim, 0.19 to 1.33 kg ha(-1) glufosinate and 0.34 to 1.14 kg ha(-1) glyphosate. Relative to other cultivars, common bermudagrass was intermediate in its response to clethodim and among the most tolerant cultivars to glufosinate and glyphosate. TifSport was relatively tolerant to clethodim and glufosinate compared with other cultivars, but relatively sensitive to glyphosate. One cultivar, 94-437, was consistently among the most sensitive cultivars to each of the herbicides. While there were differential herbicide tolerances among the tested bermudagrass cultivars, there did not appear to be any naturally occurring herbicide resistance that could be commercially utilized. However, research indicated that breeding efforts should target herbicide resistance that is at least four times the registered use rate. Also, TifSport and Tifway have been identified as suitable representatives of triploid hybrid bermudagrass cultivars to be used to evaluate the success of turfgrass renovation programs. PMID:15578605

Webster, Theodore M; Hanna, Wayne W; Mullinix, Benjamin G

2004-12-01

171

Influence of glyphosate on Rhizoctonia crown and root rot (Rhizoctonia solani) in glyphosate-resistant sugarbeet (Beta vulgaris L.)  

Science.gov (United States)

Previous greenhouse studies with a non-commercial glyphosate-resistant sugarbeet variety indicated that susceptibility to Rhizoctonia crown and root rot could increase after glyphosate was applied. Greenhouse and field experiments were conducted in 2008 and 2009 to determine if glyphosate influenced...

172

Eficiência fotossintética e uso da água em plantas de eucalipto pulverizadas com glyphosate/ Photosynthetic efficiency and water use in eucalyptus plants sprayed with glyphosate  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Objetivou-se com este trabalho avaliar a eficiência fotossintética e o uso da água por plantas de clones de eucalipto submetidas ao herbicida glyphosate. O experimento foi realizado em esquema fatorial 4 x 5, com quatro clones de eucalipto (57, 386, 1203 e 1213) e quatro doses de glyphosate (43,2; 86,2; 129,6; e 172,8 g ha-1) e uma testemunha sem herbicida, considerada dose zero, com quatro repetições. Aos 7, 14, 21 e 28 dias após aplicação do herbicida (DAA) foi (more) avaliada a intoxicação das plantas, e aos 7 e 21 DAA, o fluxo de gases pelos estômatos (U - mmol s-1), a atividade fotossintética (A - mmol m-2 s-1), a condutância estomática (Gs - mol m-1 s-1), a transpiração (E - mol H2O m-2 s-1) e a eficiência do uso da água (QUE - mol CO2 mol H2O-1). Aos 50 DAA, as plantas de eucalipto foram coletadas e colocadas em estufa de ventilação forçada a 70 ºC até atingirem massa constante. Aos 21 DAA, o clone 1203 comportou-se como mais sensível ao herbicida. Não houve diferença entre clones para as variáveis fisiológicas avaliadas. Aos 21 DAA constatou-se que, com o incremento da dose de glyphosate, houve redução na condutância estomática, na taxa de fluxo de gases pelos estômatos, na taxa fotossintética e na eficiência do uso da água. Plantas dos clones 1213 e 1203 apresentaram maior acúmulo de massa seca. O aumento da dose do glyphosate promoveu menor acúmulo de massa seca das plantas de eucalipto. O glyphosate afetou negativamente o crescimento e a eficiência fotossintética e de uso da água dos clones estudados. Abstract in english The objective of this study was to assess the photosynthetic efficiency and water use by eucalyptus clones submitted to the herbicide glyphosate. The experiment was performed in a 4 x 5 factorial, with four eucalyptus clones (57, 386, 1203 and 1213), four doses of glyphosate (43.2, 86.2, 129.6 and 172.8 g ha-1) and a control without herbicide, considered zero dose, with four replications. At 7, 14, 21 and 28 days after herbicide application (DAA), plant intoxication was e (more) valuated and at 7 and 21 DAA, stomatal gas flow (U - mmol s-1), photosynthetic activity (A -mmol m-2 s-1), stomatal conductance (Gs - mol m-1 s-1), transpiration (E - mol H2O m-2 s-1) and water use efficiency (WUE - mol CO2 mol H2O-1). At 50 DAA, the eucalyptus plants were collected and placed in a forced-ventilation oven at 70 °C until constant weight to determine dry mass. At 21 DAA, clone 1203 was found to be the most sensitive to the herbicide. There was no difference among the clones for the assessed physiological variables. At 21DAA, it was verified that increasing doses of glyphosate led to a reduction in stomatal conductance, stomatal gas flow rate, photosynthetic rate and water use efficiency. Plants of clones 1213 and 1203 showed a higher accumulation of dry mass. Increasing doses of glyphosate promoted less accumulation of dry mass in the eucalyptus plants. Glyphosate negatively affected growth, photosynthetic efficiency and water use of the evaluated clones.

Machado, A.F.L.; Ferreira, L.R.; Santos, L.D.T.; Ferreira, F.A.; Viana, R.G.; Machado, M.S.; Freitas, F.C.L.

2010-06-01

173

STUDY OF CHRONIC TOXICITY OF THE GLYPHOSATE HERBICIDE IN SEEDS OF CORN,  

Directory of Open Access Journals (Sweden)

Full Text Available Glyphosate is an agrochemical from the group of phosphonates, which is widely used as a herbicide. Although it kills almost any plant, it can be used to eliminate weeds during the growth of crops that are resistant to glyphosate. This research aimed to evaluate the toxicological effects of the herbicide in a study using as test organism seeds of maize (Zea mays), okra (Abelmoschus esculentus (L.) Moench) and arugula (Eruca sativa). The toxicological testing was to use a paper towel dampened with a sample of glyphosate and twenty seeds evenly distributed in containers with lids, left in a dry and airy place, and watered once a day for 5 days. It was possible to check the toxic effect of glyphosate for corn seeds at concentrations above 90 mg.L-1, for okra seeds at concentrations above 75 mg L-1 and arugula seeds in concentrations above 2 mg L - 1. Thus it was concluded that the seeds studied showed a high sensitivity with the possibility to be applied in toxicity testing, representing a simple and low cost.

Ana Cláudia Rebessi; Núbia Natália de Brito

2011-01-01

174

Efeito de concentrações de espalhante adesionante e doses de glyphosate no controle de Brachiaria decumbens e Panicum maximum Effects of adhesive spreading and glyphosate on Brachiaria decumbens and Panicum maximum control  

Directory of Open Access Journals (Sweden)

Full Text Available Foram avaliadas as interações entre o glyphosate e o espalhante adesionante correspondente ao condensado de alcoolfenóis com óxido de eteno e sulfonados orgânicos quanto à redução de tensão superficial e ao controle de Panicum maximum e Brachiaria decumbens. Os produtos comerciais apresentavam 360 g e.a./l e 466 g i.a./l, respectivamente. O herbicida reduziu o efeito do espalhante sobre a tensão superficial. Na concentração de 0,1% de p.c., o espalhante maximizou o controle das duas espécies pelo glyphosate. P. maximum mostrou-se menos sensível ao glyphosate que B. decumbens, exigindo doses 24,05% superiores.The interactions of glyphosate and one adhesive spreading (concentrate of alcoholphenols with ethene-oxide and organic sulfonates) in reducing the surface tension and controlling Brachiaria decumbens and Panicum maximum were evaluated. It were used comercial products with 360 g a.e/l and 466 g i.a./l, respectivelly. To achieve similar control levels, the herbicide rates should be 24,05% higher for the second species. The herbicide reduced the effect of the surfactant on surface tension. The concentration of 0,1 % (c.p.) of the surfactant maximized the efficacy of glyphosate in controlling the two grasses.

Edivaldo D. Velini; Dagoberto Martins; Marco A. de Souza Silva

2000-01-01

175

Glyphosate como regulador de crescimento em arroz de terras altas/ Use of glyphosate as growth regulator in upland rice  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O acamamento de algumas cultivares de arroz, no momento da colheita, acarreta perdas significativas na produtividade e, além disto, manejos de água e nitrogênio inadequados, em condições de alta tecnologia, agravam, ainda mais, o problema. O uso de reguladores vegetais é uma das alternativas para se reduzir o acamamento, entretanto, as informações sobre o assunto são escassas. O trabalho objetivou avaliar o uso de subdoses de glyphosate (26 g ha-1, 52 g ha-1, 78 (more) g ha-1, 104 g ha-1, 130 g ha-1, 156 g ha-1 e 182 g ha-1) sobre as características agronômicas, desenvolvimento e produtividade do arroz de terras altas irrigado por aspersão, aplicadas na época da diferenciação floral. O experimento foi desenvolvido no município de Selvíria (MS), durante os anos agrícolas 2008/2009 e 2009/2010. O aumento das subdoses de glyphosate, aplicadas na época da diferenciação floral da cultivar Primavera, reduziu a altura de plantas, o tamanho das panículas e, consequentemente, a produtividade. Subdoses iguais ou superiores a 78 g ha-1 eliminaram o acamamento de plantas. Abstract in english The lodging of some rice cultivars at harvest time can lead to significant losses in yield, and the inappropriate water and nitrogen management, under high-tech conditions, can aggravate the problem. The use of vegetal regulators is an alternative to reduce lodging, however, information on this topic are rare. The study aimed to evaluate the application of glyphosate sub doses (26 g ha-1, 52 g ha-1, 78 g ha-1, 104 g ha-1, 130 g ha-1, 156 g ha-1, and 182 g ha-1) on agronom (more) ical traits, development, and yield of upland rice crops irrigated by aspersion, during the floral differentiation period. The experiment was carried out in Selvíria, Mato Grosso do Sul State, Brazil, through the agricultural years of 2008/2009 and 2009/2010. The increase of glyphosate sub doses, at the floral differentiation period of the Primavera cultivar, reduced the plants height, panicle size, and, consequently, yield. Sub doses higher than or equal to 78 g ha-1 eliminated the plants lodging process.

Gitti, Douglas de Castilho; Arf, Orivaldo; Peron, Igor Balbi Guirão; Portugal, José Roberto; Corsini, Daiene Camila Dias Chaves; Rodrigues, Ricardo Antônio Ferreira

2011-12-01

176

USE OF GLYPHOSATE AS GROWTH REGULATOR IN UPLAND RICE GLYPHOSATE COMO REGULADOR DE CRESCIMENTO EM ARROZ DE TERRAS ALTAS  

Directory of Open Access Journals (Sweden)

Full Text Available The lodging of some rice cultivars at harvest time can lead to significant losses in yield, and the inappropriate water and nitrogen management, under high-tech conditions, can aggravate the problem. The use of vegetal regulators is an alternative to reduce lodging, however, information on this topic are rare. The study aimed to evaluate the application of glyphosate sub doses (26 g ha-1, 52 g ha-1, 78 g ha-1, 104 g ha-1, 130 g ha-1, 156 g ha-1, and 182 g ha-1) on agronomical traits, development, and yield of upland rice crops irrigated by aspersion, during the floral differentiation period. The experiment was carried out in Selvíria, Mato Grosso do Sul State, Brazil, through the agricultural years of 2008/2009 and 2009/2010. The increase of glyphosate sub doses, at the floral differentiation period of the Primavera cultivar, reduced the plants height, panicle size, and, consequently, yield. Sub doses higher than or equal to 78 g ha-1 eliminated the plants lodging process.O acamamento de algumas cultivares de arroz, no momento da colheita, acarreta perdas significativas na produtividade e, além disto, manejos de água e nitrogênio inadequados, em condições de alta tecnologia, agravam, ainda mais, o problema. O uso de reguladores vegetais é uma das alternativas para se reduzir o acamamento, entretanto, as informações sobre o assunto são escassas. O trabalho objetivou avaliar o uso de subdoses de glyphosate (26 g ha-1, 52 g ha-1, 78 g ha-1, 104 g ha-1, 130 g ha-1, 156 g ha-1 e 182 g ha-1) sobre as características agronômicas, desenvolvimento e produtividade do arroz de terras altas irrigado por aspersão, aplicadas na época da diferenciação floral. O experimento foi desenvolvido no município de Selvíria (MS), durante os anos agrícolas 2008/2009 e 2009/2010. O aumento das subdoses de glyphosate, aplicadas na época da diferenciação floral da cultivar Primavera, reduziu a altura de plantas, o tamanho das panículas e, consequentemente, a produtividade. Subdoses iguais ou superiores a 78 g ha-1 eliminaram o acamamento de plantas.

Douglas de Castilho Gitti; Orivaldo Arf; Igor Balbi Guirão Peron; José Roberto Portugal; Daiene Camila Dias Chaves Corsini; Ricardo Antônio Ferreira Rodrigues

2011-01-01

177

Aplicação foliar de manganês em soja transgênica tolerante ao glyphosate Foliar application of manganese in transgenic soybean tolerant to glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available O amarelecimento da soja Roundup Ready após aplicação do glyphosate pode estar associado à deficiência momentânea de manganês. Por isso, com a hipótese de que soja tolerante ao glyphosate necessitaria de uma adição suplementar de manganês, o objetivo deste trabalho foi avaliar diferentes manejos na aplicação foliar de manganês sobre alguns parâmetros da soja. Foram desenvolvidos dois experimentos, um no município de Taquaruçú do Sul e outro em Boa Vista das Missões, RS, no ano agrícola 2009/2010. Foram testados os seguintes tratamentos: 1) sem aplicação de glyphosate, com controle manual das plantas daninhas e sem aplicação foliar de manganês (testemunha); 2) sem aplicação de glyphosate, com controle manual das plantas daninhas e uma aplicação foliar de manganês sete dias após esse controle manual das plantas daninhas; 3) com aplicação de glyphosate e sem aplicação foliar de manganês; 4) aplicação de glyphosate em mistura com manganês; 5) aplicação de glyphosate mais uma aplicação foliar de manganês sete dias após aplicação do glyphosate; 6) aplicação de glyphosate mais aplicação foliar de manganês parcelada em duas épocas, aos 7 e 14 dias após aplicação do glyphosate; 7) aplicação de glyphosate e uma aplicação foliar de manganês aos 14 dias após aplicação de glyphosate. A aplicação de glyphosate foi realizada no estádio V5 da soja, na dose de 720g L-1 e.a, enquanto a dose de Mn utilizada foi 2,0L ha-1 de uma formulação contendo 14% (m/v) de manganês solúvel. Não houve diferença significativa entre os tratamentos para as variáveis estatura de plantas e altura de inserção da primeira vagem. A aplicação de glyphosate não afetou a absorção e o teor foliar de manganês e nitrogênio na cultura da soja. Mesmo com aumento no teor foliar de manganês com a suplementação de manganês, não houve incremento na produtividade da soja. Isso mostra que em solos com teores de Mn acima do suficiente a aplicação do herbicida glifosato não requer a suplementação foliar de manganês em soja geneticamente modificada tolerante a esse herbicida.The yellowing of Roundup Ready soybean after glyphosate application, can be associated to a momentary manganese deficiency. Because of that, with the hypothesis that glyphosate tolerant soybean would need supplementary addition of manganese, the objective of this research was to evaluate different managements in the foliar application of manganese in some soybean parameters. It was developed two experiments, one at Taquaruçú do Sul and other at Boa Vista das Missões, RS in the year of 2009/2010. It was tested the following treatments: 1) without glyphosate application with manual weed control and without manganese foliar application (untreated check); 2) without glyphosate application with manual weed control and one manganese foliar application at 7 days after this manual weed control; 3) with glyphosate application and without manganese foliar application; 4) glyphosate application in mixture with manganese; 5) glyphosate application added of one manganese foliar application at 7 days after glyphosate application; 6) glyphosate application added of manganese foliar application split in two times, at 7 and 14 days after glyphosate application; 7) glyphosate application and one of manganese foliar application at 14 days after glyphosate application. The glyphosate application was realized in the V5 soybean stage, using 720g L-1 i.e, while the used dose of Mn was 2.0L ha-1 of a formulation with 14% (m/v) of Mn. There were no significant difference among the treatments to plant height and height insertion of the first legume. The glyphosate application did not affect the absorption and the foliar amount of manganese and nitrogen in soybean crop. Even with the increase in foliar manganese amount, there was no increasing in soybean productivity. This shows that in soils with Mn levels above of the sufficient, it is not necessary foliar manganese addition in genetically modified soybean tolerant t

Claudir José Basso; Antônio Luis Santi; Fabiane Pinto Lamego; Eduardo Girotto

2011-01-01

178

Leaching of glyphosate and AMPA under two soil management practices in Burgundy vineyards (Vosne-Romanee, 21-France)  

Energy Technology Data Exchange (ETDEWEB)

Some drinking water reservoirs under the vineyards of Burgundy are contaminated with herbicides. Thus the effectiveness of alternative soil management practices, such as grass cover, for reducing the leaching of glyphosate and its metabolite, AMPA, through soils was studied. The leaching of both molecules was studied in structured soil columns under outdoor conditions for 1 year. The soil was managed under two vineyard soil practices: a chemically treated bare calcosol, and a vegetated calcosol. After 680 mm of rainfall, the vegetated calcosol leachates contained lower amounts of glyphosate and AMPA (0.02% and 0.03%, respectively) than the bare calcosol leachates (0.06% and 0.15%, respectively). No glyphosate and only low amounts of AMPA (<0.01%) were extracted from the soil. Glyphosate, and to a greater extent, AMPA, leach through the soils; thus, both molecules may be potential contaminants of groundwater. However, the alternative soil management practice of grass cover could reduce groundwater contamination by the pesticide. - Glyphosate and AMPA leached in greater amounts through a chemically treated bare calcosol than through a vegetated calcosol.

Landry, David [UMR 1229 INRA/Universite de Bourgogne, Microbiologie et Geochimie des sols, Centre des Sciences de la Terre, Universite de Bourgogne, 6 bd Gabriel 21000 Dijon (France)]. E-mail: david.landry@u-bourgogne.fr; Dousset, Sylvie [UMR 1229 INRA/Universite de Bourgogne, Microbiologie et Geochimie des sols, Centre des Sciences de la Terre, Universite de Bourgogne, 6 bd Gabriel 21000 Dijon (France); Fournier, Jean-Claude [UMR 1229 INRA/Universite de Bourgogne, INRA, 17 rue Sully, 21000 Dijon (France); Andreux, Francis [UMR 1229 INRA/Universite de Bourgogne, Microbiologie et Geochimie des sols, Centre des Sciences de la Terre, Universite de Bourgogne, 6 bd Gabriel 21000 Dijon (France)

2005-11-15

179

AUXIN-PRODUCING BACTERIA AND UREASE ACTIVITY IN THE RHIZOSPHERE OF GLYPHOSATE-RESISTANT SOYBEAN  

Science.gov (United States)

Repeated use of glyphosate on glyphosate-resistant crops has raised concerns regarding the potential environmental impacts of this herbicide. Glyphosate may affect microbial production of plant-growth-regulating compounds including hydrogen cyanide, phytohormones including auxins, and other unidenti...

180

The use of BMED for glyphosate recovery from glyphosate neutralization liquor in view of zero discharge.  

UK PubMed Central (United Kingdom)

Alkaline glyphosate neutralization liquors containing a high salinity pose a severe environmental pollution problem by the pesticide industry. However, there is a high potential for glyphosate recovery due to the high concentration of glyphosate in the neutralization liquors. In the study, a three-compartment bipolar membrane electrodialysis (BMED) process was applied on pilot scale for the recovery of glyphosate and the production of base/acid with high concentration in view of zero discharge of wastewater. The experimental results demonstrate that BMED can remove 99.0% of NaCl from the feed solution and transform this fraction into HCl and NaOH with high concentration and purity. This is recycled for the hydrolysis reaction of the intermediate product generated by the means of the Mannich reaction of paraformaldehyde, glycine and dimethylphosphite catalyzed by triethylamine in the presence of HCl and reclamation of the triethylamine catalyst during the production process of glyphosate. The recovery of glyphosate in the feed solution was over 96%, which is acceptable for industrial production. The current efficiency for producing NaOH with a concentration of 2.0molL(-1) is above 67% and the corresponding energy consumption is 2.97kWhkg(-1) at a current density of 60mAcm(-2). The current efficiency increases and energy consumption decreases as the current density decreases, to 87.13% and 2.37kWhkg(-1), respectively, at a current density of 30mAcm(-2). Thus, BMED has a high potential for desalination of glyphosate neutralization liquor and glyphosate recovery, aiming at zero discharge and resource recycling in industrial application.

Shen J; Huang J; Liu L; Ye W; Lin J; Van der Bruggen B

2013-09-01

 
 
 
 
181

The use of BMED for glyphosate recovery from glyphosate neutralization liquor in view of zero discharge.  

Science.gov (United States)

Alkaline glyphosate neutralization liquors containing a high salinity pose a severe environmental pollution problem by the pesticide industry. However, there is a high potential for glyphosate recovery due to the high concentration of glyphosate in the neutralization liquors. In the study, a three-compartment bipolar membrane electrodialysis (BMED) process was applied on pilot scale for the recovery of glyphosate and the production of base/acid with high concentration in view of zero discharge of wastewater. The experimental results demonstrate that BMED can remove 99.0% of NaCl from the feed solution and transform this fraction into HCl and NaOH with high concentration and purity. This is recycled for the hydrolysis reaction of the intermediate product generated by the means of the Mannich reaction of paraformaldehyde, glycine and dimethylphosphite catalyzed by triethylamine in the presence of HCl and reclamation of the triethylamine catalyst during the production process of glyphosate. The recovery of glyphosate in the feed solution was over 96%, which is acceptable for industrial production. The current efficiency for producing NaOH with a concentration of 2.0molL(-1) is above 67% and the corresponding energy consumption is 2.97kWhkg(-1) at a current density of 60mAcm(-2). The current efficiency increases and energy consumption decreases as the current density decreases, to 87.13% and 2.37kWhkg(-1), respectively, at a current density of 30mAcm(-2). Thus, BMED has a high potential for desalination of glyphosate neutralization liquor and glyphosate recovery, aiming at zero discharge and resource recycling in industrial application. PMID:23832058

Shen, Jiangnan; Huang, Jie; Liu, Lifen; Ye, Wenyuan; Lin, Jiuyang; Van der Bruggen, Bart

2013-06-19

182

The effect of glyphosate on import into a sink leaf of sugar beet  

Energy Technology Data Exchange (ETDEWEB)

The basis for glyphosate inducted limitation of carbon import into developing leaves was studied in sugar beet. To separate the effects of the herbicide on export from those on import, glyphosate was supplied to a developing leaf from two exporting source leaves which fed the sink leaf. Carbon import into the sink leaf was determined by supplying {sup 14}CO{sub 2} to a third source leaf which also supplies carbon to the monitored sink leaf. Import into the sink leaf decreased within 2 to 3 h after glyphosate application, even though photosynthesis and export in the source leaf supplying {sup 14}C were unaffected. Reduced import into the sink leaf was accompanied by increased import by the tap root. Elongation of the sink leaf was only slightly decreased following arrival of glyphosate. Photosynthesis by the sink leaf was not inhibited. The results to data support the view that import is slowed by the inhibition of synthesis of structural or storage compounds in the developing leaves.

Shieh, Wenjang; Geiger, D.R. (Univ. of Dayton, OH (USA))

1990-05-01

183

Glyphosate and bioherbicide interaction for controlling kudzu (Pueraria lobata), redvine (Brunnichia ovata), and trumpetcreeper (Campsis radicans)  

UK PubMed Central (United Kingdom)

In controlled environment experiments, the bioherbicidal fungus Myrothecium verrucaria (Alb. & Schwein.) Ditmar:Fr. was tested alone, in combination with, prior to, and following treatment with glyphosate N-(phosphonomethyl)glycine for control of kudzu Pueraria lobata (Willd.) Ohwi, redvine Brunnichia ovata (Walt.) Shinners, and trumpetcreeper Campsis radicans (L.) Seem. ex Bureau at temperatures of 20, 30, and 40 degrees C. At all temperatures, kudzu was most adversely affected by the fungus, followed by trumpetcreeper and redvine, as indicated by greater mortality and dry weight reductions. Trumpetcreeper and redvine mortalities and dry weight reductions significantly increased when the fungus was applied 2 days after the glyphosate treatment. Application of the fungus combined with or prior to glyphosate treatment resulted in reduced weed control. Although pathogenesis and mortality also occurred at 20 degrees C, disease development was favored by higher temperatures (30 and 40 degrees C). Infected weeds of each species exhibited similar disease symptomatology within 12 h following treatment at incubation temperatures of 30 and 40 degrees C. Disease symptomatology was characterized by necrotic flecking on leaves that coalesced into large lesions. Symptoms progressed, initially infecting cotyledons and leaves, and later (within 48 h) producing stem lesions. The fungus sporulated profusely on infected tissue and was easily reisolated. These results suggest that timing of glyphosate application in relation to combined treatment with the bioherbicide M. verrucaria can improve the control of kudzu, redvine, and trumpetcreeper.

Boyette CD; Reddy KN; Hoagland RE

2006-01-01

184

Reduced Sensitivity to Slow-Rate Dynamic Auditory Information in Children with Dyslexia  

Science.gov (United States)

|The etiology of developmental dyslexia remains widely debated. An appealing theory postulates that the reading and spelling problems in individuals with dyslexia originate from reduced sensitivity to slow-rate dynamic auditory cues. This low-level auditory deficit is thought to provoke a cascade of effects, including inaccurate speech perception…

Poelmans, Hanne; Luts, Heleen; Vandermosten, Maaike; Boets, Bart; Ghesquiere, Pol; Wouters, Jan

2011-01-01

185

Reduced baroreflex sensitivity and pulmonary dysfunction in alcoholic cirrhosis: effect of hyperoxia  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Patients with cirrhosis exhibit impaired regulation of the arterial blood pressure, reduced baroreflex sensitivity (BRS), and prolonged QT interval. In addition, a considerable number of patients have a pulmonary dysfunction with hypoxemia, impaired lung diffusing capacity (Dl(CO)), and presence of ...

Møller, Søren; Iversen, Jens S; Krag, Aleksander; Bie, Peter; Kjaer, Andreas; Bendtsen, Flemming

186

Influence of late emerging weeds in glyphosate-resistant corn  

Directory of Open Access Journals (Sweden)

Full Text Available Fifteen field trials were conducted from 2009 to 2011 in Ontario, Canada and Michigan, USA to determine how long glyphosate-resistant corn needs to be kept weed-free after emergence to prevent yield loss. Data were separated into two environments based on when yield loss first occurred after glyphosate application. In Environment 1 (4/15 sites) yield was not reduced when corn was kept weed-free until the 4-leaf stage. However, in Environment 2 (11/15 sites) there was no yield loss when corn was kept weed-free up to the 2-leaf stage. The most prominent weeds were velvetleaf, redroot pigweed, common ragweed, common lambsquarters and foxtail species. While later emerging weeds did not necessarily impact corn yield, weeds emerging after the 2- and 4-leaf corn stage likely produced seed that was added to the soil seed bank. Weeds emerging after 6-, 8-, and 10-leaf corn growth stages were small (low biomass/seedlings) and most likely did not reach reproductive maturity. Based on this research, corn must be maintained weed-free up to the 4-leaf stage. Any weeds emerging after that did not influence corn yield.

Nader Soltani; Robert E. Nurse; Eric Page; Wesley J. Everman; Christy L. Sprague; Peter H. Sikkema

2013-01-01

187

Toxicity of formulated glyphosate (glyphos) and cosmo-flux to larval Colombian frogs 1. Laboratory acute toxicity.  

UK PubMed Central (United Kingdom)

The spraying of coca (Erythroxylum coca) with glyphosate in Colombia has raised concerns about possible impacts on amphibians. There are few toxicity data for species other than those from temperate regions, and these have not been generated with the combination of formulated glyphosate (Glyphos) and the adjuvant, Cosmo-Flux (coca mix) as used in coca control in Colombia. In order to characterize toxicity of the spray mixture to frogs from Colombia, Gosner stage-25 tadpoles of Scinax ruber, Dendropophus microcephalus, Hypsiboas crepitans, Rhinella granulosa, Rhinella marina, Rhinella typhonius, Centrolene prosoblepon, and Engystomops pustulosus were exposed to the coca mix at concentrations of glyphosate ranging from 1 to 4.2 mg a.e./L diluted in dechlorinated tap water in glass containers. Cosmo-Flux was added to Glyphos in the proportion of 2.3% v/v, as used in aerial application for coca control. Exposures were for 96 h at 23 +/- 1.5 degrees C with 12:12-h light/dark cycle. Test solutions were renewed every 24 h. Concentrations, measured within the first hour and at 24 and 96 h using enzyme-linked immunosorbent assay (ELISA) (Abraxis, LLC), ranged from 70 to 130% of nominal values. LC50 values ranged from 1200 to 2780 microg glyphosate acid equivalents (a.e.)/L for the 8 species tested. Data suggest that sensitivity to Roundup-type formulations of glyphosate in these species is similar to that observed in other tropical and temperate species. In addition, sensitivity of larval amphibians to Roundup-type formulations spans a relatively narrow range. Finally, toxicity of the mixture as used to spray coca was likely driven by the surfactant in the glyphosate formulation, as the addition of Cosmo-Flux did not enhance toxicity above those reported for Vision = Roundup.

Bernal MH; Solomon KR; Carrasquilla G

2009-01-01

188

Toxicity of formulated glyphosate (glyphos) and cosmo-flux to larval Colombian frogs 1. Laboratory acute toxicity.  

Science.gov (United States)

The spraying of coca (Erythroxylum coca) with glyphosate in Colombia has raised concerns about possible impacts on amphibians. There are few toxicity data for species other than those from temperate regions, and these have not been generated with the combination of formulated glyphosate (Glyphos) and the adjuvant, Cosmo-Flux (coca mix) as used in coca control in Colombia. In order to characterize toxicity of the spray mixture to frogs from Colombia, Gosner stage-25 tadpoles of Scinax ruber, Dendropophus microcephalus, Hypsiboas crepitans, Rhinella granulosa, Rhinella marina, Rhinella typhonius, Centrolene prosoblepon, and Engystomops pustulosus were exposed to the coca mix at concentrations of glyphosate ranging from 1 to 4.2 mg a.e./L diluted in dechlorinated tap water in glass containers. Cosmo-Flux was added to Glyphos in the proportion of 2.3% v/v, as used in aerial application for coca control. Exposures were for 96 h at 23 +/- 1.5 degrees C with 12:12-h light/dark cycle. Test solutions were renewed every 24 h. Concentrations, measured within the first hour and at 24 and 96 h using enzyme-linked immunosorbent assay (ELISA) (Abraxis, LLC), ranged from 70 to 130% of nominal values. LC50 values ranged from 1200 to 2780 microg glyphosate acid equivalents (a.e.)/L for the 8 species tested. Data suggest that sensitivity to Roundup-type formulations of glyphosate in these species is similar to that observed in other tropical and temperate species. In addition, sensitivity of larval amphibians to Roundup-type formulations spans a relatively narrow range. Finally, toxicity of the mixture as used to spray coca was likely driven by the surfactant in the glyphosate formulation, as the addition of Cosmo-Flux did not enhance toxicity above those reported for Vision = Roundup. PMID:19672764

Bernal, M H; Solomon, K R; Carrasquilla, G

2009-01-01

189

RHIZOSPHERE ECOLOGY AND GLYPHOSATE-RESISTANT SOYBEAN  

Science.gov (United States)

The interaction of glyphosate-resistant (GR) soybean with the ecology of plant-associated microbial populations has been the subject of environmental assessments in response to the public concern regarding the ecological compatibility of transgenic crops. Changes in the dynamics of soil and rhizosph...

190

Effects of glyphosate on isolated maize mitochondria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The effects of the herbicide glyphosate (K+ salt) on isolated maize mitochondria have been investigated. Protein synthesis, oxygen uptake (state 3 and state 4 respiration) and passive swelling were inhibited at concentrations in the 10?6–10?2 M range. No decrease of the respiratory control ratio (RC...

Lopez Braña, Isidoro; Delibes Castro, Angeles; García Olmedo, Francisco

191

Glyphosate-Resistant Goosegrass from Mississippi  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A suspected glyphosate-resistant goosegrass [Eleusine indica (L.) Gaertn.] population, found in Washington County, Mississippi, was studied to determine the level of resistance and whether the resistance was due to a point mutation, as was previously identified in a Malaysian population. Whole plant...

William T. Molin; Alice A. Wright; Vijay K. Nandula

192

Manejo de Conyza bonariensis resistente ao herbicida glyphosate/ Management of Glyphosate-resistant Conyza bonariensis  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese C. bonariensis (Conyza bonariensis) é uma planta daninha da família Asteraceae, amplamente distribuída no Brasil, com presença marcante nos Estados do Rio Grande do Sul e do Paraná. Biótipos de C. bonariensis resistentes ao glyphosate foram identificados nos Estados do Rio Grande do Sul, Paraná e São Paulo. O objetivo deste trabalho foi avaliar o efeito de diferentes manejos de inverno e na pré-semeadura da soja sobre a população de plantas de C. bonariensis re (more) sistente ao herbicida glyphosate. Os resultados evidenciaram que a população de C. bonariensis é maior em áreas mantidas sem cultivo (pousio) do que naquelas áreas cultivadas com trigo ou aveia-preta durante o inverno. Observou-se que o trigo e a aveia-preta exercem efeito supressor sobre a população de C. bonariensis, proporcionando maior facilidade de controle com herbicida na pré-semeadura da cultura usada em sucessão. O controle de C. bonariensis resistente ao herbicida glyphosate foi satisfatório quando se utilizaram herbicidas pós-emergentes na cultura do trigo e glyphosate + 2,4-D ou glyphosate + diuron + paraquat na pré-semeadura da soja. Abstract in english Horseweed (Conyza bonariensis), which belongs to the Asteraceae family, is a weed species widely spread in Brazil. Horseweed biotypes resistant to glyphosate, the main herbicide used in Roundup Ready soybean fields, were identified in the states of Rio Grande do Sul and Parana. The aim of this study was to evaluate the effect of different winter and pre-sowing management techniques on soybean plant population of C. bonariensis resistant to glyphosate. The results showed t (more) hat the population of C. bonariensis is larger in areas maintained fallow than in areas planted with wheat or oats during the winter. Wheat and oats were found to exert a suppressive effect on the population of C. bonariensis, providing greater ease of control with herbicide before seeding in the culture used in succession. The control of glyphosate-resistant C. bonariensis was satisfactory when post-emergence herbicides were used in wheat crop and glyphosate and 2,4-D or glyphosate paraquat diuron in pre-planting soybeans.

Paula, J.M.; Vargas, L.; Agostinetto, D.; Nohatto, M.A.

2011-03-01

193

Effects of glyphosate on cholinesterase activity of the mussel Perna perna and the fish Danio rerio and Jenynsia multidentata: in vitro studies.  

UK PubMed Central (United Kingdom)

Although the herbicide glyphosate [N-(phosphonomethyl)glycine] is not classified as an acethylcholinesterase inhibitor, some studies have reported reduction in the acethylcolinesterase activity after in vivo exposure to both its pure form and its commercial formulations. Considering this controversy, the objective of the present study was to investigate, in vitro, the effects of glyphosate exposure on cholinesterase activity of the brown mussel Perna perna and of two fish species: zebrafish Danio rerio and onesided livebearer Jenynsia multidentata. For this purpose, samples of different tissues (brain and muscle for fish; gills and muscle for mussel) were homogenized and pre-incubated with different glyphosate concentrations before cholinesterase activity determination. Results demonstrated that cholinesterase from different fractions of all species tested was inhibited by glyphosate. The concentrations of glyphosate that inhibits 50% of cholinesterase activity (IC50) ranged from 0.62 mM for P. perna muscle to 8.43 mM for J. multidentata brain. According to this, cholinesterase from mussel seems to be more sensitive to glyphosate exposure than those from the fish D. rerio and J. multidentata.

Sandrini JZ; Rola RC; Lopes FM; Buffon HF; Freitas MM; Martins Cde M; da Rosa CE

2013-04-01

194

Effects of glyphosate on cholinesterase activity of the mussel Perna perna and the fish Danio rerio and Jenynsia multidentata: in vitro studies.  

Science.gov (United States)

Although the herbicide glyphosate [N-(phosphonomethyl)glycine] is not classified as an acethylcholinesterase inhibitor, some studies have reported reduction in the acethylcolinesterase activity after in vivo exposure to both its pure form and its commercial formulations. Considering this controversy, the objective of the present study was to investigate, in vitro, the effects of glyphosate exposure on cholinesterase activity of the brown mussel Perna perna and of two fish species: zebrafish Danio rerio and onesided livebearer Jenynsia multidentata. For this purpose, samples of different tissues (brain and muscle for fish; gills and muscle for mussel) were homogenized and pre-incubated with different glyphosate concentrations before cholinesterase activity determination. Results demonstrated that cholinesterase from different fractions of all species tested was inhibited by glyphosate. The concentrations of glyphosate that inhibits 50% of cholinesterase activity (IC50) ranged from 0.62 mM for P. perna muscle to 8.43 mM for J. multidentata brain. According to this, cholinesterase from mussel seems to be more sensitive to glyphosate exposure than those from the fish D. rerio and J. multidentata. PMID:23411353

Sandrini, Juliana Zomer; Rola, Regina Coimbra; Lopes, Fernanda Moreira; Buffon, Hermeson Francisco; Freitas, Milene Marques; Martins, Camila de Martinez Gaspar; da Rosa, Carlos Eduardo

2013-01-18

195

The effect of reduced oxygen levels on the electrostatic ignition sensitivity of dusts  

Energy Technology Data Exchange (ETDEWEB)

When handling powders with low values of minimum ignition energy (MIE), it is often necessary to employ additional protective measures such as explosion venting, suppression, containment or inerting. Inerting generally involves reducing the oxygen concentration to around 5% v/v; however, it has been shown with gases that more modest reductions in the oxygen content can still have a significant effect on the MIE. Therefore, a test program was carried out to assess the impact of reduced oxygen levels on the MIE of a series of sensitive powders. In addition, this work was also used to investigate whether testing of such sensitive materials in the standard equipment but with reduced oxygen levels could enable the prediction of MIEs <1 mJ at standard atmospheric oxygen levels.

Ackroyd, Graham; Bailey, Mike; Mullins, Robert [Syngenta Process Hazards Section, Huddersfield, HD2 2GZ (United Kingdom)

2011-06-23

196

Side-effects of glyphosate on the life parameters of Eriopis connexa (Coleoptera: Coccinelidae) in Argentina.  

Science.gov (United States)

In Argentina, transgenic soybean crop (Roundup Ready, RR) has undergone a major expansion over the last 15 years, with the consequent increase of glyphosate applications, a broad-spectrum and post emergence herbicide. Soybean crops are inhabited by several arthropods. Eriopis connexa Germar (Coleoptera: Coccinelidae) is a predator associated to soybean soft-bodies pest and have a Neotropical distribution. Nowadays, it is being considered a potentially biological control agent in South America. The objectives of this work were to evaluate the side-effects of glyphosate on larvae (third instar) and adults of this predator. Commercial compound and the maximum registered concentrations for field use were employed: GlifoGlex 48 (48% glyphosate, 192 mg a.i./litre, Gleba Argentina S.A.). The exposure was by ingestion through the treated prey (Rophalosiphum padi) or by drinking treated water during 48 h for treatment of the adult. The herbicide solutions were prepared using distilled water as solvent. The bioassays were carried out in the laboratory under controlled conditions: 23 +/- 0.5 degrees C, 75 +/- 5% RH and 16:8 (L:D) of photoperiod. Development time, weight of pupae, adult emergence, pre-oviposition period, fecundity and fertility were evaluated as endpoints. Larvae from glyphosate treatment molted earlier than controls. In addition, the weight of pupae, longevity, fecundity and fertility were drastically reduced in treated organisms. The reductions were more drastic when the treatments were performed at the third larval stage than as adult. The reproduction capacity of the predator was the most affected parameter and could be related to a hormonal disruption by glyphosate in the treated organisms. This work can confirm the deleterious effects of this herbicide on beneficial organisms. Also, it agrees with prior studies carried out on other predators associated to soybean pest, such as Chrysoperla externa (Neuroptera: Chrysopidae) and Alpaida veniliae (Araneae: Araneidae). PMID:21539255

Mirande, L; Haramboure, M; Smagghe, G; Piñeda, S; Schneider, M I

2010-01-01

197

Differential response of two sourgrass populations to glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available The repetitive use of glyphosate may cause increase on the resistance of sourgrass (Digitaria insularis) through mechanisms of natural selection. The aim of this study was to verify the response of two populations of sourgrass (one collected from nonagricultural area and the other one from area suspected of glyphosate resistance) to increasing doses of glyphosate. The experimental design was completely randomized with four repetitions. For both populations, glyphosate was sprayed at 10 doses (0D, D/16, D/8, D/4, D/2, D, 2D, 4D, 8D, and 16D; so that D is the dose of 1.08 kg e.a. ha-1). The treatments were sprayed when the plants had shown 3-5 tillers. The population collected in the nonagricultural area was slightly more sensible to the herbicide glyphosate than the population originated from an area where the herbicide application is common, not indicating glyphosate resistance.

Paulo Roberto Fidelis Giancotti; Bruna Pires da Silva; São Paulo State University, Jaboticabal, SP, Brazil; Leonardo Bianco de Carvalho; Pedro Luis da Costa Aguiar Alves

2013-01-01

198

Early supplementation with Lactobacillus rhamnosus HN001 reduces eczema prevalence to 6 years: does it also reduce atopic sensitization?  

UK PubMed Central (United Kingdom)

BACKGROUND: The role of probiotics in prevention of allergic disease is still not clear; efficacy may depend on the timing, dose, duration, and specific probiotic used. Using a double-blind randomized placebo-controlled trial (Australian New Zealand Clinical Trials Registry: ACTRN12607000518460), we have shown that in a high-risk birth cohort, maternal supplementation from 35 weeks gestation until 6 months if breastfeeding and infant supplementation from birth until 2 years with Lactobacillus rhamnosus HN001 (HN001) (6 × 10(9)  cfu/day) halved the cumulative prevalence of eczema at 2 and 4 years. Bifidobacterium animalis subsp lactis HN019 (HN019) (9 × 10(9)  cfu/day) had no significant effect. OBJECTIVE: To determine whether differences in effects of HN001 and HN019 on eczema persist to age 6 years, and to investigate effects on sensitization. METHODS: Standard procedures were used to assess eczema (The UK Working Party's Criteria), eczema severity (SCORAD), atopic sensitization [skin prick tests (SPT), total and specific IgE] and standard questions used for asthma, wheeze, and rhinoconjunctivitis. RESULTS: HN001 was associated with significantly lower cumulative prevalence of eczema (HR = 0.56, 95% CI 0.39-0.80), SCORAD ? 10 (HR = 0.69, 0.49-0.98) and SPT sensitization (HR = 0.69, 95% CI 0.48-0.99). The point prevalence of eczema (RR = 0.66, 95% CI 0.44-1.00), SCORAD ? 10 (RR = 0.62, 95% CI 0.38-1.01) and SPT sensitization (RR = 0.72, 95% CI 0.53-1.00) were also reduced among children taking HN001. HN019 had no significant effect on any outcome. CONCLUSION AND CLINICAL RELEVANCE: This study provides evidence for the efficacy of the probiotic L. rhamnosus HN001 in preventing the development of eczema and possibly also atopic sensitization in high risk infants to age 6 years. The absence of a similar effect for HN019 indicates that benefits may be species specific.

Wickens K; Stanley TV; Mitchell EA; Barthow C; Fitzharris P; Purdie G; Siebers R; Black PN; Crane J

2013-09-01

199

Differential contributions of impaired corneal sensitivity and reduced tear secretion to corneal epithelial disorders.  

UK PubMed Central (United Kingdom)

BACKGROUND/AIMS: To determine the possible roles of impaired corneal sensitivity and reduced tear secretion in various types of corneal epithelial disorders. METHODS: A total of 99 patients (179 eyes) with corneal epithelial disorders classified as persistent epithelial defects (PED), corneal erosion, or superficial punctate keratopathy (SPK) and 115 individuals (230 eyes) without apparent ocular surface disorders (controls) were enrolled in a prospective study. Corneal sensitivity was measured with a Cochet-Bonnet esthesiometer, and tear secretion was measured by the Schirmer test in each subject. RESULTS: Corneal sensitivity of eyes in the PED and corneal erosion groups was significantly lower than that in the control group. Schirmer test values for eyes in the SPK group were significantly reduced compared with those in the control group. CONCLUSION: A loss of corneal sensitivity may contribute to the development of PED and corneal erosion, whereas reduced tear secretion may be a contributing factor for SPK. Both results indicate the importance of corneal sensory innervation to the maintenance of corneal integrity.

Nishida T; Chikama T; Sawa M; Miyata K; Matsui T; Shigeta K

2012-01-01

200

An Assessment of the Impact of Glyphosate and 2,4-D Amine Salt on Weeds in Niger  

Directory of Open Access Journals (Sweden)

Full Text Available An experiment was carried out to investigate the efficacy of two herbicides, viz., glyphosate and 2,4- D amine salt at varying doses for the control of the main noxious weeds. The lowest application rate (0.5l per ha of 2,4-D and 2l per ha of glyphosate) of both herbicides gave a control of shoot grow th and drastically reduced the green biomass compared to unweeded plots at different time intervals after the application. There was no re-growth up to nine days after spraying in all treated plots. The highest control of the density of noxious weeds has been obtained with 2,4-D amine salt at the dose of 1.5 l per ha and glyphosate at the dose of 4l per ha in six days after treatment; the reduction rate was more than 85%. Data on green biomass also showed drastic reduction following herbicide application.

A. Mamadou; A. Haougui; B.M. Coulibaly; A. Moumouni and O. Garba

2010-01-01

 
 
 
 
201

Leaching of glyphosate and AMPA under two soil management practices in Burgundy vineyards (Vosne-Romanee, 21-France)  

International Nuclear Information System (INIS)

Some drinking water reservoirs under the vineyards of Burgundy are contaminated with herbicides. Thus the effectiveness of alternative soil management practices, such as grass cover, for reducing the leaching of glyphosate and its metabolite, AMPA, through soils was studied. The leaching of both molecules was studied in structured soil columns under outdoor conditions for 1 year. The soil was managed under two vineyard soil practices: a chemically treated bare calcosol, and a vegetated calcosol. After 680 mm of rainfall, the vegetated calcosol leachates contained lower amounts of glyphosate and AMPA (0.02% and 0.03%, respectively) than the bare calcosol leachates (0.06% and 0.15%, respectively). No glyphosate and only low amounts of AMPA (

2005-01-01

202

Sensitive high-throughput screening for the detection of reducing sugars.  

UK PubMed Central (United Kingdom)

The exploitation of renewable resources for the production of biofuels relies on efficient processes for the enzymatic hydrolysis of lignocellulosic materials. The development of enzymes and strains for these processes requires reliable and fast activity-based screening assays. Additionally, these assays are also required to operate on the microscale and on the high-throughput level. Herein, we report the development of a highly sensitive reducing-sugar assay in a 96-well microplate screening format. The assay is based on the formation of osazones from reducing sugars and para-hydroxybenzoic acid hydrazide. By using this sensitive assay, the enzyme loads and conversion times during lignocellulose hydrolysis can be reduced, thus allowing higher throughput. The assay is about five times more sensitive than the widely applied dinitrosalicylic acid based assay and can reliably detect reducing sugars down to 10 ?M. The assay-specific variation over one microplate was determined for three different lignocellulolytic enzymes and ranges from 2 to 8%. Furthermore, the assay was combined with a microscale cultivation procedure for the activity-based screening of Pichia pastoris strains expressing functional Thermomyces lanuginosus xylanase A, Trichoderma reesei ?-mannanase, or T. reesei cellobiohydrolase 2.

Mellitzer A; Glieder A; Weis R; Reisinger C; Flicker K

2012-01-01

203

Glyphosate-Resistant Giant Ragweed (Ambrosia trifida L.) in Ontario: Dose Response and Control with Postemergence Herbicides  

Directory of Open Access Journals (Sweden)

Full Text Available Giant ragweed (Ambrosia trifida L.) is competitive with agronomic crops and can cause significant yield losses. Rapid adoption of glyphosate-resistant (GR) crops and a concomitant increase in the reliance on glyphosate for weed management has led to the evolution of GR giant ragweed in Ontario, Canada. Field studies were conducted to evaluate the level of resistance in giant ragweed biotypes from Ontario, and to evaluate the effectiveness of various postemer-gence (POST) herbicides in soybean (Glycine max L.). The effective dose (ED) to provide 50%, 80% and 95% giant ragweed control was up to 1658, 9991 and >43200 g?a.e.?ha–1 4 weeks after application (WAA), respectively. For effective control, growers would need to apply glyphosate 18 times greater than the recommended field application dose. Glyphosate applied at the recommended field dose of 900 g?a.e.?ha–1 provided up to 57% control and resulted in soybean yield equivalent to the weedy check. Cloransulam-methyl applied POST provided up to 99% control, reduced giant ragweed density 98%, reduced giant ragweed shoot dry weight 99% and resulted in soybean yield equivalent to the weedfree check. Chlorimuron-ethyl, fomesafen, imazethapyr and imazethapyr plus bentazon applied alone or with glyphosate did not provide adequate control of GR giant ragweed. Based on these results, some GR giant ragweed biotypes from Ontario have evolved a high level of resistance to glyphosate. Cloransulam-methyl applied POST was the only herbicide that provided adequate control and suggests that additional weed management tactics will need to be implemented in order to effectively manage GR giant ragweed.

Joseph P. Vink; Nader Soltani; Darren E. Robinson; François J. Tardif; Mark B. Lawton; Peter H. Sikkema

2012-01-01

204

Distance from a distance: psychological distance reduces sensitivity to any further psychological distance.  

Science.gov (United States)

What is the difference between far and further? Investigations into such psychological distancing--removal from an egocentric reference point--have suggested similarities between geographical space, time, probability, and social distance. We draw on these similarities to propose that experiencing any kind of distance will reduce sensitivity to any other distance. Nine studies varied the initial distance of an event and assessed sensitivity to a second distance. Consistently, people were less responsive to a given span of distance when it was distal versus proximal. This effect held using each of the four distances as the initial instantiation of distance; it also held using each dimension to assess sensitivity to distance (i.e., as the second distance dimension). These findings suggest that the dimensions of psychological distance share a common, interchangeable meaning and that the cross-dimension difference between far and further is less than that between near and far. PMID:23025560

Maglio, Sam J; Trope, Yaacov; Liberman, Nira

2012-10-01

205

Distance from a distance: psychological distance reduces sensitivity to any further psychological distance.  

UK PubMed Central (United Kingdom)

What is the difference between far and further? Investigations into such psychological distancing--removal from an egocentric reference point--have suggested similarities between geographical space, time, probability, and social distance. We draw on these similarities to propose that experiencing any kind of distance will reduce sensitivity to any other distance. Nine studies varied the initial distance of an event and assessed sensitivity to a second distance. Consistently, people were less responsive to a given span of distance when it was distal versus proximal. This effect held using each of the four distances as the initial instantiation of distance; it also held using each dimension to assess sensitivity to distance (i.e., as the second distance dimension). These findings suggest that the dimensions of psychological distance share a common, interchangeable meaning and that the cross-dimension difference between far and further is less than that between near and far.

Maglio SJ; Trope Y; Liberman N

2013-08-01

206

Manejo de tiririca e trapoeraba com glyphosate em ambientes sombreados Commelina benghalensis and Cyperus rotundus treated with glyphosate in shaded environments  

Directory of Open Access Journals (Sweden)

Full Text Available Plantas daninhas mantidas em ambientes com redução da intensidade luminosa apresentam alterações morfofisiológicas marcantes, que podem alterar seu comportamento reprodutivo e a tolerância a herbicidas aplicados em pós-emergência. Objetivou-se neste estudo avaliar a eficiência de doses de glyphosate no manejo da trapoeraba (Commelina benghalensis) e da tiririca (Cyperus rotundus) cultivadas em diferentes níveis de sombreamento. O trabalho foi composto por dois ensaios, referentes a cada uma das espécies, com o mesmo delineamento experimental, sendo constituídos em esquema fatorial 5 x 3, com cinco doses de herbicida (0, 540, 810, 1.080 ou 1.350 g ha-1 de glyphosate), três ambientes de cultivo (0, 30 ou 50% de sombra) e quatro repetições. As parcelas experimentais foram compostas por um vaso com duas plantas de tiririca ou de trapoeraba. As avaliações de controle ocorreram aos 10, 20 e 30 dias após a aplicação (DAA), por meio de observações visuais. Aos 30 DAA, foi determinada a massa seca da parte aérea de cada espécie. A produtividade de tubérculos foi observada pela contagem direta desses propágulos presentes nas raízes das plantas de tiririca. Já a sua viabilidade foi avaliada por teste de germinação em leito de areia e por tetrazólio no caso dos não germinados. O controle das espécies foi mais eficiente em ambientes sombreados, contribuindo para a redução de até 25% da dose recomendada para ambas, obtendo-se controle de 81% para trapoeraba e 100% para tiririca. Já a matéria seca da parte aérea, a produtividade e a viabilidade dos tubérculos foram afetadas pelo aumento do nível de sombra e pela dose de glyphosate. A diminuição da intensidade luminosa - comum no sub-bosque de culturas arbóreas e arbustivas ou quando do adensamento de cultivos - representa prática interessante na supressão da trapoeraba e da tiririca e potencializa a ação de controle do glyphosate.Weeds maintained in reduced light intensity environments present remarkable morpho-physiological changes that may alter their reproductive behavior and tolerance to post-emergence herbicides. Our goal was to evaluate the efficiency of glyphosate doses in the management of Commelina benghalensis and Cyperus rotundus grown at different levels of shading. The work consisted of two trials for each species with the same experimental design, in a 5 x 3 factorial design with five herbicide doses (0, 540, 810, 1.080, and 1.350 gha-1 of glyphosate), three cultivation environments (0, 30, or 50% of shading) and four replicates. Experimental plots consisted of a vase with two plants of either C. benghalensis or C. rotundus. Control evaluations were carried out 10, 20, and 30 days after application (DAA) through visual observations. Tuber productivity was verified by direct counting of these propagules present in the roots of C. rotundus plants, while tuber viability was evaluated by germination test in a sand bed, and by tetrazolium, for the non-germinated tubers. Species control was more efficient in shade environments, contributing to a reduction of up to 25% of the recommended dose for the treated species, and resulting in a control of 81% for C. benghalensis and 100% for C. rotundus. Aerial part dry biomass and productivity and viability of tubers were affected by increase in shade level and glyphosate dose. Reduced light intensity - common in the under-story of tree and shrub cultures or in culture density - is an interesting practice aiming at suppressing C. benghalensis and C. rotundus, acting as a potential control of glyphosate.

A Santos Júnior; L.D Tuffi Santos; G.A Costa; E.A Barbosa; G.L.D Leite; V.D Machado; L.R Cruz

2013-01-01

207

Resposta de plantas de beterraba (Beta vulgaris) e de cenoura (Daucus carota) à deriva simulada de glyphosate e clomazone Response of beetroot (Beta vulgaris) and carrot (Daucus carota) to simulated glyphosate and clomazone drift  

Directory of Open Access Journals (Sweden)

Full Text Available Várias espécies de hortaliças são de muita importância para a alimentação humana e tornam-se alvos da deriva de herbicidas, pois comumente são cultivadas nas proximidades de culturas como arroz, soja e milho, pulverizadas com esses produtos. Neste trabalho, objetivou-se verificar possíveis efeitos de doses reduzidas dos herbicidas glyphosate e clomazone sobre plantas de beterraba (Beta vulgaris) e de cenoura (Daucus carota), em diferentes fases de desenvolvimento. As doses avaliadas dos herbicidas foram de 0, 5, 10, 15 e 20% da dose recomendada, equivalentes a 0, 63, 126, 189 e 252 g ha-1 de glyphosate e 0, 14,4, 28,8, 43,2 e 57,6 g ha-1 de clomazone, respectivamente, aplicadas aos 20, 30 e 40 dias após a emergência das culturas. Observou-se aumento no percentual de fitotoxicidade do glyphosate com o incremento na dose do herbicida, e a maior suscetibilidade ocorreu com a deriva nos estádios mais precoces, em ambas as espécies. As doses de clomazone não causaram qualquer sintoma detectável visualmente para as plantas de beterraba e de cenoura. Os resultados sugerem que o herbicida glyphosate causa injúrias às plantas de beterraba e cenoura, independentemente do estádio em que ocorre a interceptação do produto. No entanto, o herbicida clomazone não interfere no desenvolvimento inicial de plantas de beterraba e cenoura.Herbicide drift over horticultural crops is a common problem in the state of Rio Grande do Sul, mainly in areas near rice, soybean and corn fields. The objective of this research was to evaluate glyphosate and clomazone drift effects on beetroot (Beta vulgaris) and carrot (Daucus carota) plants. The herbicides were sprayed at three different growth stages: 20, 30 and 40 days after seedling emergence. Herbicide rates evaluated were 0, 5, 10, 15, and 20% of the label rate. The sprayed rates were 0, 63, 126, 189 and 252 g ha-1 of glyphosate and 0.0, 14.4, 28.8, 43.2 and 57.6 g ha-1 of clomazone. Glyphosate injury to beetroot and carrot increased with herbicide rate, with the highest injury being observed at the earlier growth stage. Clomazone did not injure beetroot and carrot plants at any tested rate or growth stage. The results of this study suggest that glyphosate drift damages beetroot and carrot at any growth stage. However, beetroot and carrot are not sensitive to clomazone drift.

R.P. Rogoli; L.C. Fontana; S.S. Figueredo; J.A. Noldin

2008-01-01

208

Resposta de plantas de beterraba (Beta vulgaris) e de cenoura (Daucus carota) à deriva simulada de glyphosate e clomazone/ Response of beetroot (Beta vulgaris) and carrot (Daucus carota) to simulated glyphosate and clomazone drift  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Várias espécies de hortaliças são de muita importância para a alimentação humana e tornam-se alvos da deriva de herbicidas, pois comumente são cultivadas nas proximidades de culturas como arroz, soja e milho, pulverizadas com esses produtos. Neste trabalho, objetivou-se verificar possíveis efeitos de doses reduzidas dos herbicidas glyphosate e clomazone sobre plantas de beterraba (Beta vulgaris) e de cenoura (Daucus carota), em diferentes fases de desenvolvimento (more) . As doses avaliadas dos herbicidas foram de 0, 5, 10, 15 e 20% da dose recomendada, equivalentes a 0, 63, 126, 189 e 252 g ha-1 de glyphosate e 0, 14,4, 28,8, 43,2 e 57,6 g ha-1 de clomazone, respectivamente, aplicadas aos 20, 30 e 40 dias após a emergência das culturas. Observou-se aumento no percentual de fitotoxicidade do glyphosate com o incremento na dose do herbicida, e a maior suscetibilidade ocorreu com a deriva nos estádios mais precoces, em ambas as espécies. As doses de clomazone não causaram qualquer sintoma detectável visualmente para as plantas de beterraba e de cenoura. Os resultados sugerem que o herbicida glyphosate causa injúrias às plantas de beterraba e cenoura, independentemente do estádio em que ocorre a interceptação do produto. No entanto, o herbicida clomazone não interfere no desenvolvimento inicial de plantas de beterraba e cenoura. Abstract in english Herbicide drift over horticultural crops is a common problem in the state of Rio Grande do Sul, mainly in areas near rice, soybean and corn fields. The objective of this research was to evaluate glyphosate and clomazone drift effects on beetroot (Beta vulgaris) and carrot (Daucus carota) plants. The herbicides were sprayed at three different growth stages: 20, 30 and 40 days after seedling emergence. Herbicide rates evaluated were 0, 5, 10, 15, and 20% of the label rate. (more) The sprayed rates were 0, 63, 126, 189 and 252 g ha-1 of glyphosate and 0.0, 14.4, 28.8, 43.2 and 57.6 g ha-1 of clomazone. Glyphosate injury to beetroot and carrot increased with herbicide rate, with the highest injury being observed at the earlier growth stage. Clomazone did not injure beetroot and carrot plants at any tested rate or growth stage. The results of this study suggest that glyphosate drift damages beetroot and carrot at any growth stage. However, beetroot and carrot are not sensitive to clomazone drift.

Rogoli, R.P.; Fontana, L.C.; Figueredo, S.S.; Noldin, J.A.

2008-06-01

209

Is the application of a residual herbicide required prior to glyphosate application in no-till glyphosate-tolerant soybean (Glycine max)  

UK PubMed Central (United Kingdom)

In no-till glyphosate-tolerant soybean multiple applications of glyphosate may be required to maintain weed control throughout the season. Another approach that may improve weed control and aid in the stewardship of glyphosate use is to apply a pre-emergence residual herbicide such as flufenacet plus metribuzin prior to a single in-crop application of glyphosate. There is limited information on the optimal glyphosate application timing in glyphosate-tolerant soybeans (Glycine max) following the application of a residual herbicide such as flufenacet plus metribuzin. Field trials using factorial designs were conducted at three Ontario locations, in 1999 and 2000 to evaluate the efficacy of flufenacet plus metribuzin applied pre-plant or pre-emergence followed by a post-emergence application of glyphosate in glyphosate-tolerant soybean. Crop tolerance was acceptable for all treatments (flufenacet plus metribuzin, glyphosate and flufenacet plus metribuzin followed by glyphosate). Control of Echinochloa crus-galli and Setaria viridis was excellent using glyphosate and thus soil-applied applications of flufenacet plus metribuzin did not improve control. Control of Chenopodium album, Ambrosia artemisiifolia and Abutilon theophrasti with flufenacet plus metribuzin was poor at all application timings whereas a post-emergence application of glyphosate provided excellent annual broadleaved weed control. There was no difference in soybean yield among the three glyphosate timings evaluated. Overall, there was no benefit from the application of the residual herbicide applied prior to glyphosate.

Nurse RE; Hamill AS; Swanton CJ; Tardif FJ; Deen W; Sikkema PH

2007-04-01

210

Suscetibilidade de genótipos de Lolium multiflorum ao herbicida glyphosate/ Susceptibility of Lolium multiflorum genotypes to glyphosate  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Objetivou-se com este trabalho avaliar o grau de tolerância dos genótipos diploides e tetraploides de L. multiflorum (azevém) ao herbicida glyphosate. Para isso, foram instalados quatro experimentos, sendo um para cada estádio fenológico do azevém (duas folhas, quatro perfilhos, pré-florescimento e formação de grãos). Utilizou-se delineamento em blocos casualizados com arranjo fatorial 2 x 6 (dois genótipos e seis doses do herbicida glyphosate: 240, 480, 960, 1 (more) .920, 3.840 e 7.680 g e.a. ha-1) e uma testemunha sem aplicação de glyphosate, com quatro repetições. Os parâmetros analisados foram porcentagem de controle e fitomassa seca da parte aérea das plantas. Os resultados foram submetidos à análise de variância e, em seguida, ajustados para modelo de curva de dose-resposta do tipo logística, sendo desses modelos calculados valores de controle correspondentes a 50, 80, 90 e 99%. Os genótipos de azevém diploide apresentaram suscetibilidade diferencial ao herbicida glyphosate, sendo o genótipo tetraploide mais tolerante ao herbicida que o diploide. O grau diferencial de tolerância, medido pelo fator de tolerância diferencial entre os genótipos, foi de 1,6 vez a dose de glyphosate no genótipo tetraploide em relação ao diploide. Os estádios fenológicos de desenvolvimento das plantas de ambos os genótipos afetaram o grau de tolerância ao glyphosate. A variável fitomassa seca das plantas apresentou a mesma tendência diferencial entre os genótipos diploides e tetraploides que o parâmetro porcentagem visual de controle. Abstract in english This work aimed to evaluate the degree of tolerance of Italian ryegrass genotypes to the herbicide glyphosate. Thus, four experiments were installed, one for each phenological stage (two leaves, four tillers, pre-flowering, and grain formation). The treatments consisted of the combination of the two genotypes and six rates of glyphosate (240; 480; 960; 1,920; 3,840 and 7,680 g a.e. ha-1) and a check without glyphosate application, in a complete randomized block design and (more) four replications. The parameters analyzed were control percentage and shoot dry biomass. Results were submitted to analysis of variance and subsequently adjusted to non-linear log of dose-response curves, and from these models control values were calculated at 50, 80, 90 and 99%. The Italian ryegrass genotypes presented differential susceptibility to the herbicide glyphosate, with the tetraploid genotype being more tolerant to the herbicide than the diploid. The degree of differential tolerance, measured by the differential tolerance factor between the genotypes, is 1.6 times the glyphosate dose in the tetraploid genotype compared to the diploid genotype. The phenological stages of plant development of both the genotypes studied affected the degree of tolerance to glyphosate. The variable shoot dry biomass presented the same differential tendency between the diploid and tetraploid genotypes presented by the parameter visual control percentage.

Dors, C.A.; Christoffoleti, P.J.; Sanchotene, D.M.; Dias, A.C.R.; Manfron, P.A.; Dornelles, S.H.B.

2010-06-01

211

Suscetibilidade de genótipos de Lolium multiflorum ao herbicida glyphosate Susceptibility of Lolium multiflorum genotypes to glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available Objetivou-se com este trabalho avaliar o grau de tolerância dos genótipos diploides e tetraploides de L. multiflorum (azevém) ao herbicida glyphosate. Para isso, foram instalados quatro experimentos, sendo um para cada estádio fenológico do azevém (duas folhas, quatro perfilhos, pré-florescimento e formação de grãos). Utilizou-se delineamento em blocos casualizados com arranjo fatorial 2 x 6 (dois genótipos e seis doses do herbicida glyphosate: 240, 480, 960, 1.920, 3.840 e 7.680 g e.a. ha-1) e uma testemunha sem aplicação de glyphosate, com quatro repetições. Os parâmetros analisados foram porcentagem de controle e fitomassa seca da parte aérea das plantas. Os resultados foram submetidos à análise de variância e, em seguida, ajustados para modelo de curva de dose-resposta do tipo logística, sendo desses modelos calculados valores de controle correspondentes a 50, 80, 90 e 99%. Os genótipos de azevém diploide apresentaram suscetibilidade diferencial ao herbicida glyphosate, sendo o genótipo tetraploide mais tolerante ao herbicida que o diploide. O grau diferencial de tolerância, medido pelo fator de tolerância diferencial entre os genótipos, foi de 1,6 vez a dose de glyphosate no genótipo tetraploide em relação ao diploide. Os estádios fenológicos de desenvolvimento das plantas de ambos os genótipos afetaram o grau de tolerância ao glyphosate. A variável fitomassa seca das plantas apresentou a mesma tendência diferencial entre os genótipos diploides e tetraploides que o parâmetro porcentagem visual de controle.This work aimed to evaluate the degree of tolerance of Italian ryegrass genotypes to the herbicide glyphosate. Thus, four experiments were installed, one for each phenological stage (two leaves, four tillers, pre-flowering, and grain formation). The treatments consisted of the combination of the two genotypes and six rates of glyphosate (240; 480; 960; 1,920; 3,840 and 7,680 g a.e. ha-1) and a check without glyphosate application, in a complete randomized block design and four replications. The parameters analyzed were control percentage and shoot dry biomass. Results were submitted to analysis of variance and subsequently adjusted to non-linear log of dose-response curves, and from these models control values were calculated at 50, 80, 90 and 99%. The Italian ryegrass genotypes presented differential susceptibility to the herbicide glyphosate, with the tetraploid genotype being more tolerant to the herbicide than the diploid. The degree of differential tolerance, measured by the differential tolerance factor between the genotypes, is 1.6 times the glyphosate dose in the tetraploid genotype compared to the diploid genotype. The phenological stages of plant development of both the genotypes studied affected the degree of tolerance to glyphosate. The variable shoot dry biomass presented the same differential tendency between the diploid and tetraploid genotypes presented by the parameter visual control percentage.

C.A. Dors; P.J. Christoffoleti; D.M. Sanchotene; A.C.R. Dias; P.A. Manfron; S.H.B. Dornelles

2010-01-01

212

Rhizosphere processes as determinants for glyphosate damage of non-target plants  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Due to low production costs and high herbicidal efficiency, glyphosate is the most widely used wide-spectrum herbicide. Glyphosate acts as a non-selective, total herbicide by inhibiting the biosynthesis of aromatic amino acids. Apart from glyphosate drift contamination, risks of glyphosate toxicity ...

Bott, Sebastian

213

Tactile motion adaptation reduces perceived speed but shows no evidence of direction sensitivity.  

UK PubMed Central (United Kingdom)

INTRODUCTION: While the directionality of tactile motion processing has been studied extensively, tactile speed processing and its relationship to direction is little-researched and poorly understood. We investigated this relationship in humans using the 'tactile speed aftereffect' (tSAE), in which the speed of motion appears slower following prolonged exposure to a moving surface. METHOD: We used psychophysical methods to test whether the tSAE is direction sensitive. After adapting to a ridged moving surface with one hand, participants compared the speed of test stimuli on the adapted and unadapted hands. We varied the direction of the adapting stimulus relative to the test stimulus. RESULTS: Perceived speed of the surface moving at 81 mms(-1) was reduced by about 30% regardless of the direction of the adapting stimulus (when adapted in the same direction, Mean reduction = 23 mms(-1), SD = 11; with opposite direction, Mean reduction = 26 mms(-1), SD = 9). In addition to a large reduction in perceived speed due to adaptation, we also report that this effect is not direction sensitive. CONCLUSIONS: Tactile motion is susceptible to speed adaptation. This result complements previous reports of reliable direction aftereffects when using a dynamic test stimulus as together they describe how perception of a moving stimulus in touch depends on the immediate history of stimulation. Given that the tSAE is not direction sensitive, we argue that peripheral adaptation does not explain it, because primary afferents are direction sensitive with friction-creating stimuli like ours (thus motion in their preferred direction should result in greater adaptation, and if perceived speed were critically dependent on these afferents' response intensity, the tSAE should be direction sensitive). The adaptation that reduces perceived speed therefore seems to be of central origin.

McIntyre S; Holcombe AO; Birznieks I; Seizova-Cajic T

2012-01-01

214

Controle de Brachiaria brizantha com uso do glyphosate após o estabelecimento de Tifton 85 (Cynodon spp.) Control of Brachiaria brizantha with glyphosate's after Tifton's 85 (Cynodon spp.) establishment  

Directory of Open Access Journals (Sweden)

Full Text Available A eficiência do glyphosate no controle de Brachiaria brizantha cv. Marandu em áreas de cultivo do Tifton 85 foi avaliada utilizando o delineamento experimental em blocos casualizados, com oito doses de glyphosate (0, 90, 180, 360, 720, 1.080, 1.440 e 1.800 g ha-1), e quatro repetições. Cada parcela foi constituída de um vaso com duas plantas de B. brizantha cv. Marandu e duas plantas de Tifton-85. A aplicação do herbicida foi feita quando as plantas de B. brizantha apresentavam cerca de 40 cm de altura. O nível de intoxicação nas plantas de Tifton 85 e a eficiência do herbicida no controle de B. brizantha foram avaliados aos 15, 30 e 60 dias após aplicação (DAA). Aos 60 DAA, as plantas foram colhidas ao nível do solo e secas em estufa. A rebrota foi avaliada, do mesmo modo, aos 60 dias após o corte (DAC). Obeservou-se controle superior a 90% de B. brizantha, a partir da dose de 738,28 g ha-1 de glyphosate, enquanto a intoxicação para as plantas de Tifton 85 foi de apenas 12,05. Aos 60 DAA, houve redução na produção de massa seca de braquiária a partir da dose de 90 g ha-1. Doses superiores a 720 g ha-1 diminuíram o crescimento e desenvolvimento do Tifton 85, afetando sua produção, sem, no entanto, ocasionar a morte das plantas. Os resultados evidenciam boa tolerância do Tifton 85 até a dose de 720 g ha-1 de glyphosate.No information is available on selective herbicide to control Brachiaria brizantha cv. Marandu on established pasture of 'Tifton 85'. This work evaluated the selectivity of glyphosate to Tifton 85 culture, using a randomized block design, with eight glyphosate rates (0; 90; 180; 360; 720; 1.080; 1.440 and 1.800 g ha-1 ), and four replications. Each plot consisted of a pot with two Brachiaria brizantha cv. Marandu plants and two 'Tifton-85' plants. Herbicide was applied when Brachiaria was around 40 cm high. After 15, 30 and 60 days of application (DAA), intoxication level on Tifton plants and herbicide efficiency on Brachiaria control were evaluated. At 60 DAA, the plants were cut and dried in a greenhouse, and the sprouts evaluated 60 days after cut. Under 738.28 g ha-1 of glyphosate, 90% of the Brachiaria brizantha plants were controlled, while Tifton plant intoxication was observed only at 12.05%. At 60 DAA, Brachiaria dry matter production decreased from 90 g ha-1 , with total control of these plants being observed at the rate of 738.28 g ha-1. Rates higher than 720 g ha-1 reduced the growth and development of Tifton 85, affecting its production without, however, leading to death of the plants. The results evidenced good selectivity for glyphosate to Tifton 85 culture up to 720 g ha-1.

M.V. Santos; F.A. Ferreira; F.C.L. Freitas; L.D. Tuffi Santos; D.M. Fonseca

2006-01-01

215

Atividade de glutationa S-transferase na degradação do herbicida glyphosate em plantas de milho (Zea mays) Glutathione S-transferase activity on the degradation of the herbicide glyphosate in maize (Zea mays) plants  

Directory of Open Access Journals (Sweden)

Full Text Available A glutationa S-transferase (GST, EC 2.5.1.18) desempenha um papel importante na resposta do estresse causado por herbicidas nas plantas; é considerada uma enzima de desintoxicação, por metabolizar grande variedade de compostos xenobióticos, por meio da conjugação destes com glutationa reduzida, formando substâncias de baixa toxicidade. O milho (Zea mays) foi escolhido neste trabalho por apresentar problemas de injúrias quando submetido ao controle químico de plantas daninhas, por meio do uso de herbicidas. Esta pesquisa teve como objetivo determinar as alterações na atividade desta enzima em plantas de milho submetidas ao tratamento pelo herbicida glyphosate. O delineamento experimental utilizado foi o inteiramente casualizado, em esquema fatorial 4x4, com quatro tratamentos herbicidas (glyphosate nas concentrações de 1.000, 2.500 e 5.000 ppm e as plantas-controle tratadas com água) e quatro estádios de desenvolvimento (9, 16, 23 e 30 dias após a emergência), com cinco repetições. O herbicida foi aplicado na parte aérea das plântulas de milho. A parte aérea foi coletada às 24, 48 e 72 horas após a aplicação do herbicida e utilizada para a determinação da atividade da GST e do teor de lipoperóxidos. Foi verificado que os teores de lipoperóxidos não foram alterados pelo tratamento com o glyphosate, porém a atividade de GST aumentou na maioria dos tratamentos utilizados, indicando ter ação na degradação do herbicida glyphosate em plantas de milho.Glutathione S-transferase (GST, EC 2.5.1.18) plays an important role in the response to stress caused by herbicides in plants; it is considered to be a detoxifying enzyme since it metabolizes a great variety of xenobiotic compounds, by combining them with reduced glutathione, forming substances of low toxicity. Maize (Zea mays) was chosen in this work for showing injury problems when submitted to weed chemical control. This research aimed to determine the alterations in the activity of this enzyme in glyphosate-treated maize plants. The experimental design was completely randomized, in a 4 x 4 factorial arrangement, with four treatments (glyphosate at concentrations of 1,000, 2,500 and 5,000 ppm and control plant treated with water) and four developmental stages (9, 16, 23 and 30 days after emergence), with five replicates. The herbicide was applied on the maize plant shoots, which were collected at 24, 48 and 72 hours after herbicide application and utilized for determining the GST activity and lipoperoxide content. It was verified that glyphosate does not change the lipoperoxide content, but increases GST activity for most treatments utilized, indicating its action in the degradation of glyphosate in maize plants.

A.C. Cataneo; G.F.G. Déstro; L.C. Ferreira; K.L. Chamma; D.C.F. Sousa

2003-01-01

216

Reduced fear-recognition sensitivity following acute buprenorphine administration in healthy volunteers.  

Science.gov (United States)

In rodents, the endogenous opioid system has been implicated in emotion regulation, and in the reduction of fear in particular. In humans, while there is evidence that the opioid antagonist naloxone acutely enhances the acquisition of conditioned fear, there are no corresponding data on the effect of opioid agonists in moderating responses to fear. We investigated whether a single 0.2mg administration of the mu-opioid agonist buprenorphine would decrease fear sensitivity with an emotion-recognition paradigm. Healthy human subjects participated in a randomized placebo-controlled within-subject design, in which they performed a dynamic emotion recognition task 120min after administration of buprenorphine and placebo. In the recognition task, basic emotional expressions were morphed between their full expression and neutral in 2% steps, and presented as dynamic video-clips with final frames of different emotional intensity for each trial, which allows for a fine-grained measurement of emotion sensitivity. Additionally, visual analog scales were used to investigate acute effects of buprenorphine on mood. Compared to placebo, buprenorphine resulted in a significant reduction in the sensitivity for recognizing fearful facial expressions exclusively. Our data demonstrate, for the first time in humans, that acute up-regulation of the opioid system reduces fear recognition sensitivity. Moreover, the absence of an effect of buprenorphine on mood provides evidence of a direct influence of opioids upon the core fear system in the human brain. PMID:22651957

Ipser, Jonathan C; Terburg, David; Syal, Supriya; Phillips, Nicole; Solms, Mark; Panksepp, Jaak; Malcolm-Smith, Susan; Thomas, Kevin; Stein, Dan J; van Honk, Jack

2012-05-30

217

Reduced fear-recognition sensitivity following acute buprenorphine administration in healthy volunteers.  

UK PubMed Central (United Kingdom)

In rodents, the endogenous opioid system has been implicated in emotion regulation, and in the reduction of fear in particular. In humans, while there is evidence that the opioid antagonist naloxone acutely enhances the acquisition of conditioned fear, there are no corresponding data on the effect of opioid agonists in moderating responses to fear. We investigated whether a single 0.2mg administration of the mu-opioid agonist buprenorphine would decrease fear sensitivity with an emotion-recognition paradigm. Healthy human subjects participated in a randomized placebo-controlled within-subject design, in which they performed a dynamic emotion recognition task 120min after administration of buprenorphine and placebo. In the recognition task, basic emotional expressions were morphed between their full expression and neutral in 2% steps, and presented as dynamic video-clips with final frames of different emotional intensity for each trial, which allows for a fine-grained measurement of emotion sensitivity. Additionally, visual analog scales were used to investigate acute effects of buprenorphine on mood. Compared to placebo, buprenorphine resulted in a significant reduction in the sensitivity for recognizing fearful facial expressions exclusively. Our data demonstrate, for the first time in humans, that acute up-regulation of the opioid system reduces fear recognition sensitivity. Moreover, the absence of an effect of buprenorphine on mood provides evidence of a direct influence of opioids upon the core fear system in the human brain.

Ipser JC; Terburg D; Syal S; Phillips N; Solms M; Panksepp J; Malcolm-Smith S; Thomas K; Stein DJ; van Honk J

2013-01-01

218

Metabolism of glyphosate in Pseudomonas sp. strain LBr.  

Science.gov (United States)

Metabolism of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. strain LBr, a bacterium isolated from a glyphosate process waste stream, was examined by a combination of solid-state 13C nuclear magnetic resonance experiments and analysis of the phosphonate composition of the growth medium. Pseudomonas sp. strain LBr was capable of eliminating 20 mM glyphosate from the growth medium, an amount approximately 20-fold greater than that reported for any other microorganism to date. The bacterium degraded high levels of glyphosate, primarily by converting it to aminomethylphosphonate, followed by release into the growth medium. Only a small amount of aminomethylphosphonate (about 0.5 to 0.7 mM), which is needed to supply phosphorus for growth, could be metabolized by the microorganism. Solid-state 13C nuclear magnetic resonance analysis of strain LBr grown on 1 mM [2-13C,15N]glyphosate showed that about 5% of the glyphosate was degraded by a separate pathway involving breakdown of glyphosate to glycine, a pathway first observed in Pseudomonas sp. strain PG2982. Thus, Pseudomonas sp. strain LBr appears to possess two distinct routes for glyphosate detoxification. PMID:3223761

Jacob, G S; Garbow, J R; Hallas, L E; Kimack, N M; Kishore, G M; Schaefer, J

1988-12-01

219

Metabolism of glyphosate in Pseudomonas sp. strain LBr.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Metabolism of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. strain LBr, a bacterium isolated from a glyphosate process waste stream, was examined by a combination of solid-state 13C nuclear magnetic resonance experiments and analysis of the phosphonate composition of the growth medium. Ps...

Jacob, G S; Garbow, J R; Hallas, L E; Kimack, N M; Kishore, G M; Schaefer, J

220

Metabolism of glyphosate in Pseudomonas sp. strain LBr.  

UK PubMed Central (United Kingdom)

Metabolism of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. strain LBr, a bacterium isolated from a glyphosate process waste stream, was examined by a combination of solid-state 13C nuclear magnetic resonance experiments and analysis of the phosphonate composition of the growth medium. Pseudomonas sp. strain LBr was capable of eliminating 20 mM glyphosate from the growth medium, an amount approximately 20-fold greater than that reported for any other microorganism to date. The bacterium degraded high levels of glyphosate, primarily by converting it to aminomethylphosphonate, followed by release into the growth medium. Only a small amount of aminomethylphosphonate (about 0.5 to 0.7 mM), which is needed to supply phosphorus for growth, could be metabolized by the microorganism. Solid-state 13C nuclear magnetic resonance analysis of strain LBr grown on 1 mM [2-13C,15N]glyphosate showed that about 5% of the glyphosate was degraded by a separate pathway involving breakdown of glyphosate to glycine, a pathway first observed in Pseudomonas sp. strain PG2982. Thus, Pseudomonas sp. strain LBr appears to possess two distinct routes for glyphosate detoxification.

Jacob GS; Garbow JR; Hallas LE; Kimack NM; Kishore GM; Schaefer J

1988-12-01

 
 
 
 
221

Glyphosate catabolism by Pseudomonas sp. strain PG2982.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The pathway for the degradation of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. PG2982 has been determined by using metabolic radiolabeling experiments. Radiorespirometry experiments utilizing [3-14C]glyphosate revealed that approximately 50 to 59% of the C-3 carbon was oxidized to CO2. ...

Shinabarger, D L; Braymer, H D

222

Glyphosate applications on arable fields considerably coincide with migrating amphibians.  

UK PubMed Central (United Kingdom)

Glyphosate usage is increasing worldwide and the application schemes of this herbicide are currently changing. Amphibians migrating through arable fields may be harmed by Glyphosate applied to field crops. We investigated the population-based temporal coincidence of four amphibian species with Glyphosate from 2006 to 2008. Depending on a) age- and species-specific main migration periods, b) crop species, c) Glyphosate application mode for crops, and d) the presumed DT50 value (12 days or 47 days) of Glyphosate, we calculated up to 100% coincidence with Glyphosate. The amphibians regularly co-occur with pre-sowing/pre-emerging Glyphosate applications to maize in spring and with stubble management prior to crop sowing in late summer and autumn. Siccation treatment in summer coincides only with early pond-leaving juveniles. We suggest in-depth investigations of both acute and long-term effects of Glyphosate applications on amphibian populations not only focussed on exposure during aquatic periods but also terrestrial life stages.

Berger G; Graef F; Pfeffer H

2013-09-01

223

Potato (Solanum tuberosum) response to simulated glyphosate drift  

Science.gov (United States)

Field studies were conducted in 2008 in Ontario, OR and Paterson, WA to determine the effect of simulated glyphosate drift on 'Ranger Russet' potato injury, shikimic acid accumulation, and tuber yield. Glyphosate was applied at 8.5-, 54-, 107-, 215-, and 423 g ae ha-1; which corresponds to 0.01, 0.0...

224

Glyphosate applications on arable fields considerably coincide with migrating amphibians.  

Science.gov (United States)

Glyphosate usage is increasing worldwide and the application schemes of this herbicide are currently changing. Amphibians migrating through arable fields may be harmed by Glyphosate applied to field crops. We investigated the population-based temporal coincidence of four amphibian species with Glyphosate from 2006 to 2008. Depending on a) age- and species-specific main migration periods, b) crop species, c) Glyphosate application mode for crops, and d) the presumed DT50 value (12 days or 47 days) of Glyphosate, we calculated up to 100% coincidence with Glyphosate. The amphibians regularly co-occur with pre-sowing/pre-emerging Glyphosate applications to maize in spring and with stubble management prior to crop sowing in late summer and autumn. Siccation treatment in summer coincides only with early pond-leaving juveniles. We suggest in-depth investigations of both acute and long-term effects of Glyphosate applications on amphibian populations not only focussed on exposure during aquatic periods but also terrestrial life stages. PMID:24018602

Berger, Gert; Graef, Frieder; Pfeffer, Holger

2013-09-10

225

Soil Depth and Tillage Effects on Glyphosate Degradation  

Science.gov (United States)

The use of glyphosate-resistant crops facilitated the widespread adoption of no-tillage (NT) cropping systems. The experimental objectives were to determine glyphosate sorption, mineralization, and persistence at two depths [0- to 2- cm (A) and 2- to 10-cm (B)] in a silt loam managed under long ter...

226

A method for enhancing the rainfastness of glyphosate  

UK PubMed Central (United Kingdom)

A method to enhance the rainfastness of glyphosate by applying a composition comprising a) glyphosate or at least one agriculturally acceptable salt, derivative or mixtures thereof, and b) saflufenacil or at least one agriculturally acceptable derivative or mixtures thereof, to unwanted vegetation, crops, crop seed or other crop propagating organ.

BEGLIOMINI EDSON; YOTSUMOTO TADASHI

227

Refractory cardiopulmonary failure after glyphosate surfactant intoxication: a case report  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Glyphosate is an herbicide considered to be of low toxicity to humans because its effects are specific to plants. However, fatal reactions to glyphosate have been reported after the ingestion of large amounts. Pulmonary edema, shock, and arrhythmia were the repor...

Chang Chirn-Bin; Chang Chia-Chu

228

Novel three-dimensional acquisition order with reduced motion sensitivity for MR imaging  

International Nuclear Information System (INIS)

[en] This paper reports on acquisition order for three-dimensional (3D) volumetric MR imaging that provides considerably reduced motion sensitivity in the imaging of moving structures. In a standard 3D pulse sequence, all phase-encoding values of ky are acquired sequentially for each value of kz. Because of the long time delay between acquiring successive kz values, this strategy is highly susceptible to image corruption due to motion. For our proposed 3D square spiral acquisition order, phase encodings were acquired beginning at the central ky- kz value and then sequentially outward in a square spiral pattern. Motion sensitivity was assessed by simulation and experimental phantom and in vivo studies

1990-01-01

229

Identification of Glyphosate Resistance in Lolium rigidum Gaudin  

Directory of Open Access Journals (Sweden)

Full Text Available Glyphosate resistance was found in Lolium rigidum Gaudin (Rigid ryegrass, LOLRI) inSouth Africa. Suspected glyphosate-resistant L. rigidum populations were collected andgrown under greenhouse conditions. The plants were sprayed with a range of doses of glyphosate35 days after planting and shoot dry biomass was determined 17 days after herbicidetreatment. Based on the dose-response experiment conducted in the greenhouse,one population of L. rigidum suspected to be resistant to glyphosate was approximately 5.3fold more resistant than susceptible population. The other population was 2.8 fold moreresistant than susceptible population. Difference between the two suspected resistant populationswas 1.9 fold. All plants were treated with glyphosate (1000 g a.i. ha-1) and shikimicacid was extracted 2, 4 and 6 days after treatment. The plants of susceptible populationsaccumulated more shikimic acid than other two populations.

Danijela Pavlovi?; Charlie Reinhardt; Igor Elezovi?; Sava Vrbni?anin

2011-01-01

230

Bioassay for detection of transgenic soybean seeds tolerant to glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available Glyphosate is a systemic, nonselective, postemergence herbicide that inhibits growth of both weeds and crop plants. Once inside the plant, glyphosate interferes with biosynthesis of aromatic amino acids phenylalanine, tyrosine, and tryptophan, by inhibiting the activity of 5enolpyruvylshikimate-3-phosphate synthase (EPSPS), a key enzyme of the shikimate pathway. The objective of this work was to develop a simple, effective and inexpensible method for identification of transgenic soybean tolerant to glyphosate. This technique consisted in germinating soybean seeds in filter paper moistened with 100 to 200 muM of glyphosate. Transgenic soybean seeds tolerant to glyphosate germinated normally in this solution and, between 7 and 10 days, started to develop a primary root system. However non-transgenic seeds stopped primary root growth and emission of secondary roots.

Torres Antonio Carlos; Nascimento Warley Marco; Paiva Sonia Alessandra Vasconcelos; Aragão Fernando Antonio Souza de

2003-01-01

231

Method for producing glyphosate ammonium salt solid preparations  

UK PubMed Central (United Kingdom)

The invention relates to a manufacturing method of a herbicide, the technical proposal of which is to oxidize PMIDA to get mixed glyphosate solution, separate 20-80 percent of mother liquor after keeping stationary with reaction pressure controlled between 0.04MPa and 0.095MPa and reaction temperature controlled between 60 DEG C and 95 DEG C, take partial water from heat reaction to add the agent taking 5-30 percent weight of the mixed glyphosate solution and padding taking 2-15 percent weight of the mixed glyphosate solution into the mixed glyphosate solution after even stirring, spraying and granulation are to get granules of the glyphosate. The invention is characterized by scientific process, reasonable materials use, simple operation, low production costs and high product yields.

WEN WANG; LIANG ZHOU; GUOMING XU; DUANYONG ZHENG; HUI QIU; XIAOHUA LIU; ZHONGSHI WANG

232

Rydberg atoms with a reduced sensitivity to dc and low-frequency electric fields  

CERN Multimedia

A non-resonant microwave dressing field at 38.465 GHz was used to eliminate the static electric dipole moment difference between the $49s_{1/2}$ and $48s_{1/2}$ Rydberg states of $^{87}$Rb in dc fields of approximately 1 V/cm. The reduced susceptibility to electric field fluctuations was measured using 2-photon microwave spectroscopy. An anomalous spectral doublet is attributed to polarization ellipticity in the dressing field. The demonstrated ability to inhibit static dipole moment differences --- while retaining sensitivity to high frequency fields --- is applicable to sensors and/or quantum devices using Rydberg atoms.

Jones, L A; Martin, J D D

2013-01-01

233

Time-division SQUID multiplexers with reduced sensitivity to external magnetic fields  

CERN Multimedia

Time-division SQUID multiplexers are used in many applications that require exquisite control of systematic error. One potential source of systematic error is the pickup of external magnetic fields in the multiplexer. We present measurements of the field sensitivity figure of merit, effective area, for both the first stage and second stage SQUID amplifiers in three NIST SQUID multiplexer designs. These designs include a new variety with improved gradiometry that significantly reduces the effective area of both the first and second stage SQUID amplifiers.

Stiehl, G M; Hilton, G C; Irwin, K D; Mates, J A B; Reintsema, C D; Zink, B L

2010-01-01

234

Carbon isotope ratio measurements of glyphosate and AMPA by liquid chromatography coupled to isotope ratio mass spectrometry.  

UK PubMed Central (United Kingdom)

The interest in compound-specific isotope analysis for product authenticity control and source differentiation in environmental sciences has grown rapidly during the last decade. However, the isotopic analysis of very polar analytes is a challenging task due to the lack of suitable chromatographic separation techniques which can be used coupled to isotope ratio mass spectrometry. In this work, we present the first method to measure carbon isotope compositions of the widely applied herbicide glyphosate and its metabolite aminomethylphosphonic acid (AMPA) by liquid chromatography coupled to isotope ratio mass spectrometry. We demonstrate that this analysis can be carried out either in cation exchange or in reversed-phase separation modes. The reversed-phase separation yields a better performance in terms of resolution compared with the cation exchange method. The measurement of commercial glyphosate herbicide samples show its principal applicability and reveals a wide range of ?(13)C values between -24 and -34 ‰ for different manufacturers. The absolute minimum amounts required to perform a precise and accurate determination of carbon isotope compositions of glyphosate and AMPA were in the sub-microgram range. The method proposed is sensitive enough to further perform the experiments that are necessary to better understand the carbon isotope fractionation associated to the natural degradation of glyphosate into AMPA. Furthermore, it can be used for contaminant source allocation and product authenticity as well.

Kujawinski DM; Wolbert JB; Zhang L; Jochmann MA; Widory D; Baran N; Schmidt TC

2013-03-01

235

Carbon isotope ratio measurements of glyphosate and AMPA by liquid chromatography coupled to isotope ratio mass spectrometry.  

Science.gov (United States)

The interest in compound-specific isotope analysis for product authenticity control and source differentiation in environmental sciences has grown rapidly during the last decade. However, the isotopic analysis of very polar analytes is a challenging task due to the lack of suitable chromatographic separation techniques which can be used coupled to isotope ratio mass spectrometry. In this work, we present the first method to measure carbon isotope compositions of the widely applied herbicide glyphosate and its metabolite aminomethylphosphonic acid (AMPA) by liquid chromatography coupled to isotope ratio mass spectrometry. We demonstrate that this analysis can be carried out either in cation exchange or in reversed-phase separation modes. The reversed-phase separation yields a better performance in terms of resolution compared with the cation exchange method. The measurement of commercial glyphosate herbicide samples show its principal applicability and reveals a wide range of ?(13)C values between -24 and -34 ‰ for different manufacturers. The absolute minimum amounts required to perform a precise and accurate determination of carbon isotope compositions of glyphosate and AMPA were in the sub-microgram range. The method proposed is sensitive enough to further perform the experiments that are necessary to better understand the carbon isotope fractionation associated to the natural degradation of glyphosate into AMPA. Furthermore, it can be used for contaminant source allocation and product authenticity as well. PMID:23322349

Kujawinski, Dorothea M; Wolbert, J Benjamin; Zhang, Lijun; Jochmann, Maik A; Widory, David; Baran, Nicole; Schmidt, Torsten C

2013-01-16

236

Distribuição de glyphosate e acúmulo de nutrientes em biótipos de azevém Glyphosate distribution and nutrient accumulation in ryegrass biotypes  

Directory of Open Access Journals (Sweden)

Full Text Available Objetivou-se neste trabalho avaliar o acúmulo de nutrientes e a translocação de glyphosate em biótipos de azevém. Para isso, foram montados dois ensaios: no primeiro aplicou-se 14C-glyphosate, adicionando 10 µL da calda sobre a face adaxial da primeira folha com lígula totalmente visível, quando as plantas de azevém apresentavam três perfilhos. A quantidade de glyphosate absorvido, translocado e exsudado foi avaliada 64 horas após aplicação, por meio da medição da radiação emitida pelo 14C-glyphosate, em espectrômetro de cintilação líquida. O glyphosate foi quantificado em folha de aplicação, perfilhos, raízes e na solução nutritiva onde foram cultivados os biótipos de azevém. No segundo experimento, aplicou-se o glyphosate (480 g ha-1) tanto no biótipo sensível quanto no resistente. Após dez dias da aplicação, a parte área e as raízes das plantas foram coletadas e secas em estufa, sendo determinados os teores de macronutrientes. No primeiro ensaio, verificou-se exsudação radicular em ambos os biótipos, nos quais a quantidade de glyphosate exsudada foi semelhante, não ultrapassando 5% do total que penetrou na planta. No perfilho principal do biótipo sensível, comparado ao resistente, foi observada maior concentração do produto marcado. O biótipo resistente apresentou maior acúmulo de produto marcado na folha de aplicação; no sensível, a maior parte do glyphosate foi encontrada nas raízes. Com relação ao segundo ensaio, na presença de herbicida o biótipo sensível apresentou menor teor de fósforo tanto na parte aérea quanto na planta. Os biótipos resistente e sensível, sem aplicação de herbicida, tenderam a apresentar maiores teores de N total e N inorgânico na parte aérea e na planta como um todo, quando comparados aos tratamentos em que foi realizada a aplicação do produto. Ambos os biótipos mostraram a mesma capacidade de absorção e acúmulo de macronutrientes na ausência do produto.This work aimed to evaluate nutrient accumulation and glyphosate translocation in ryegrass biotypes. Two trials were conducted: in the first, 10 uL of 14C-glyphosate ware applied on the upper side of the first leaf showing completely visible ligule, with ryegrass plants at the three-tiller stage. The amount of glyphosate absorbed, translocated and exudated was evaluated 64 hours after application, by using a liquid scintillation spectrometer. Glyphosate was quantified in the leaf it had been applied, in the tillers, roots and in the nutritive solution the plants were grown. In the second trial, glyphosate was applied on the resistant and the susceptible biotypes at the rate of 480 g L-1. Ten days after application, the shoot and roots were collected and oven-dried and the levels of macronutrients were determined. In the first trial, root exudation was observed in both biotypes, in which the amount of exudated glyphosate was similar and not greater than 5% of the absorbed glyphosate. In the main tiller of the susceptible biotype, a higher concentration of 14C-glyphosate was observed, compared to the resistant one. The resistant biotype showed more glyphosate accumulation in the leaf it had been applied and in the susceptible biotype; most 14-C glyphosate was found in the root system. In the second trial, the susceptible biotype showed less P accumulation than the resistant one. Both the resistant and susceptible biotypes tended to accumulate more total N and inorganic N in the shoot and in the whole plant in the absence of glyphosate, compared to the applied treatments. Both biotypes presented the same absorption capacity and macronutrients accumulation in the absence of the glyphosate.

E.A. Ferreira; A.A. Silva; M.R. Reis; J.B. Santos; J.A. Oliveira; L. Vargas; K.R. Khouri; A.A. Guimarães

2008-01-01

237

Modeling of glyphosate and metal-glyphosate speciation in solution and at solution-mineral interfaces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Glyphosate (N-(phosphonomethyl)glycine, PMG, H3L) is a widely used organophosphorous herbicide. It interacts with metal ions and mineral surfaces, which may affect its mobility, degradation and bioavailability in the environment. However, these interactions are far from fully understood. This thesis...

Jonsson, Caroline

238

Uso de aminoácido exógeno na prevenção de injúrias causadas por glyphosate na soja RR/ Use of exogenous amino acid to prevent glyphosate injury in glyphosate-resistant soybean  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O aumento da área cultivada de soja resistente ao glyphosate (RR) no Brasil é resultado do benefício dessa tecnologia no manejo de plantas daninhas. No entanto, a expansão da área de soja RR aumentou significativamente o uso de glyphosate e consequentemente, em alguns casos, têm sido observados sintomas de injúrias na soja RR conhecidos como yellow flashing ou amarelecimento das folhas superiores. Nesse sentido, dois experimentos, em diferentes anos, foram conduzid (more) os em delineamento inteiramente casualizado, com quatro repetições. O primeiro teve o objetivo de avaliar a influência do glyphosate na soja RR nas variáveis fotossintéticas, nos parâmetros de nodulação e na biomassa seca da parte aérea e raiz, realizando-se a comparação entre os tratamentos BRS 242 RR sem glyphosate, BRS 242 RR + glyphosate e a isolinha parental não-RR cv. Embrapa 58, submetidas a uma dose de glyphosate de 1.200 g e.a. ha-1; aplicada no estádio V4. O segundo experimento foi conduzido visando reavaliar as variáveis fotossintéticas, de produção de biomassa e nodulação afetadas na soja RR pelo glyphosate no primeiro experimento. Entretanto, no segundo experimento foi avaliada a utilização de diversas modalidades de aplicação de aminoácidos (a.a.), sendo os diferentes tratamentos (sem a.a.; tratamento de semente com a.a; tratamento de semente com a.a. + aplicação foliar de a.a.; sem tratamento de sementes com a.a; e com aplicação foliar de a.a) combinados com diferentes doses de glyphosate (1.200 e 2.400 g e.a. ha-1), objetivando uma provável recuperação das plantas de soja com sua utilização exógena. Em ambos os experimentos, as variáveis fotossintéticas, os parâmetros de nodulação e biomassa seca da parte aérea e raiz foram afetados pela aplicação do glyphosate, porém o segundo experimento evidenciou, de modo geral, que o uso de aminoácidos via tratamento de sementes associado com aplicação foliar pode ser uma estratégia para prevenir os efeitos indesejáveis desse herbicida na cultura da soja RR. Abstract in english Cultivation of glyphosate-resistant (GR) soybeans has increased in Brazil as a result of the application of this technology in weed management systems developed for this crop. However, the expansion of GR soybean production has significantly increased the use of glyphosate and, in some cases, resulted in injury symptoms observed in GR soybean, known as "yellow flashing" or yellowing of the upper leaves. Thus, two experiments were conducted in different years. The first ex (more) periment aimed to evaluate the influence of glyphosate on GR soybeans regarding the photosynthetic variables, nodule parameters, and shoot and root dry biomass by comparing cultivar BRS 242 GR without glyphosate and BRS 242 RR + glyphosate at 1.200 g ha-1 at V4 growth stage, to the near isogenic non-GR parental line cv. Embrapa 58. The second experiment aimed to reassess the same parameters in GR soybeans at the V4 stage treated with glyphosate, plus the application of various amino acids, to evaluate the expected recovery of soybean growth under the exogenous use of supplemental amino acids. In general, the photosynthetic variables, nodulation parameters and shoot and root dry biomass were affected by glyphosate; however, the use of amino acids may be a strategy to prevent the undesirable effects of this herbicide on GR soybean

Zobiole, L.H.S.; Oliveira Jr., R.S.; Constantin, J.; Biffe, D.F.; Kremer, R.J.

2010-01-01

239

Shock Reactivity Study on Standard and Reduced Sensitivity Rdx of Different Particle Size Distributions  

Science.gov (United States)

Embedded gauge experiments have been performed using a three inch high velocity powder gun to assess the effects of RDX particle size and crystal quality on shock induced reactivity in support of the Combat Safe Insensitive Munitions (CSIM) program. Four monomodal experimental compositions containing 73% solids loading by weight and 27% HTPB binder were tested. The compositions were made using either standard or reduced sensitivity grades of RDX in Class 5 or Class 1 150-300 micron sieve cut particle size classes. Results have shown marked changes in the mode of reaction between the two particle size classes. Both RDX grades at the Class 1 sieve cut particle size distribution showed significant reaction at the shock front as well as behind the front. The Class 5 RDX compositions however showed little reaction at the shock front with rapid growth behind the front. Reaction modes were similar but occurring at greater input pressures for the reduced sensitivity grade of RDX compared to the corresponding particle size distribution standard grade RDX counterpart.

McGregor, N. M.; Lindfors, A. J.

2007-12-01

240

Improved insulin sensitivity associated with reduced mitochondrial complex IV assembly and activity.  

UK PubMed Central (United Kingdom)

Mice lacking Surf1, a complex IV assembly protein, have ?50-70% reduction in cytochrome c oxidase activity in all tissues yet a paradoxical increase in lifespan. Here we report that Surf1(-/-) mice have lower body (15%) and fat (20%) mass, in association with reduced lipid storage, smaller adipocytes, and elevated indicators of fatty acid oxidation in white adipose tissue (WAT) compared with control mice. The respiratory quotient in the Surf1(-/-) mice was significantly lower than in the control animals (0.83-0.93 vs. 0.90-0.98), consistent with enhanced fat utilization in Surf1(-/-) mice. Elevated fat utilization was associated with increased insulin sensitivity measured as insulin-stimulated glucose uptake, as well as an increase in insulin receptor levels (?2-fold) and glucose transporter type 4 (GLUT4; ?1.3-fold) levels in WAT in the Surf1(-/-) mice. The expression of peroxisome proliferator-activated receptor ?-coactivator 1-? (PGC-1?) mRNA and protein was up-regulated by 2.5- and 1.9-fold, respectively, in WAT from Surf1(-/-) mice, and the expression of PGC-1? target genes and markers of mitochondrial biogenesis was elevated. Together, these findings point to a novel and unexpected link between reduced mitochondrial complex IV activity, enhanced insulin sensitivity, and increased mitochondrial biogenesis that may contribute to the increased longevity in the Surf1(-/-) mice.

Deepa SS; Pulliam D; Hill S; Shi Y; Walsh ME; Salmon A; Sloane L; Zhang N; Zeviani M; Viscomi C; Musi N; Van Remmen H

2013-04-01

 
 
 
 
241

Effect of reducing groundwater on the retardation of redox-sensitive radionuclides  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Laboratory batch sorption experiments were used to investigate variations in the retardation behavior of redox-sensitive radionuclides. Water-rock compositions were designed to simulate subsurface conditions at the Nevada Test Site (NTS), where a suite of radionuclides were deposited as a result of underground nuclear testing. Experimental redox conditions were controlled by varying the oxygen content inside an enclosed glove box and by adding reductants into the testing solutions. Under atmospheric (oxidizing) conditions, radionuclide distribution coefficients varied with the mineralogic composition of the sorbent and the water chemistry. Under reducing conditions, distribution coefficients showed marked increases for 99Tc (from 1.22 at oxidizing to 378 mL/g at mildly reducing conditions) and 237Np (an increase from 4.6 to 930 mL/g) in devitrified tuff, but much smaller variations in alluvium, carbonate rock, and zeolitic tuff. This effect was particularly important for 99Tc, which tends to be mobile under oxidizing conditions. A review of the literature suggests that iodine sorption should decrease under reducing conditions when I- is the predominant species; this was not consistently observed in batch tests. Overall, sorption of U to alluvium, devitrified tuff, and zeolitic tuff under atmospheric conditions was less than in the glove-box tests. However, the mildly reducing conditions achieved here were not likely to result in substantial U(VI) reduction to U(IV). Sorption of Pu was not affected by the decreasing Eh conditions achieved in this study, as the predominant sorbed Pu species in all conditions was expected to be the low-solubility and strongly sorbing Pu(OH)4. Depending on the aquifer lithology, the occurrence of reducing conditions along a groundwater flowpath could potentially contribute to the retardation of redox-sensitive radionuclides 99Tc and 237Np, which are commonly identified as long-term dose contributors in the risk assessment in various radionuclide environmental contamination scenarios. The implications for increased sorption of 99Tc and 237Np to devitrified tuff under reducing conditions are significant as the fractured devitrified tuff serves as important water flow path at the NTS and the horizon for a proposed repository to store high-level nuclear waste at Yucca Mountain.

Hu QH; Zavarin M; Rose TP

2008-01-01

242

Glyphosate em mistura com herbicidas alternativos para o manejo de plantas daninhas/ Glyphosate combined with alternative herbicides for vegetation management  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O uso intensivo de glyphosate como herbicida não-seletivo tem selecionado espécies de plantas daninhas tolerantes. Dessa forma, é importante que sejam estudadas misturas de tanque com herbicidas de mecanismos de ação alternativos e que apresentem efeitos sinergísticos ou aditivos. Por essa razão, foi instalado um experimento inteiramente casualizado, composto por 13 tratamentos e 4 repetições, em casa de vegetação da Universidade de São Paulo - ESALQ/USP, Pira (more) cicaba-SP, com as plantas daninhas Richardia brasiliensis, Commelina benghalensis, Amaranthus hybridus, Galinsoga parviflora e Ipomoea grandifolia em misturas de tanque dos herbicidas chlorimuron-ethyl, sulfentrazone, carfentrazone, bentazon ou flumioxazin com glyphosate. As interações foram aditivas para as plantas daninhas I. grandifolia e C. benghalensis, e os herbicidas flumioxazin, sulfentrazone e carfentrazone aplicados isoladamente e em mistura com glyphosate foram os que proporcionaram os melhores níveis de controle. A interação de glyphosate com sulfentrazone foi antagônica em R. brasiliensis; a mistura de glyphosate com os demais herbicidas estudados foi aditiva, sendo os tratamentos com mistura de glyphosate e chlorimuron-ethyl ou flumioxazin os mais eficazes. Em A. hybridus, os tratamentos que apresentaram melhores níveis de controle foram o glyphosate e carfentrazone, aplicados isoladamente, e a mistura de glyphosate com flumioxazin, sulfentrazone, chlorimuron-ethyl e bentazon, sendo estes interações aditivas. No caso de G. parviflora, os tratamentos com flumioxazin e sulfentrazone apresentaram controle total, o mesmo acontecendo com as misturas de glyphosate com carfentrazone, flumioxazin, sulfentrazone, chlorimuron-ethyl ou bentazon. Abstract in english The intensive use of glyphosate as a non-selective herbicide for weed vegetation management has selected some tolerant weed species. Thus, it is important to study the synergistic or antagonic or additive effects of tank mixtures of glyphosate combined with alternative mechanism of action herbicides. An experiment was developed in a randomized complete design, using 12 treatments and four replications, under greenhouse conditions at University of São Paulo - USP/ESALQ - (more) Piracicaba-SP, Brazil, with the weeds Richardia brasiliensis, Commelina benghalensis, Amaranthus hybridus, Galinsoga parviflora and Ipomoea grandifolia and applying glyphosate combined with the herbicides chlorimuron-ethyl, carfentrazone, bentazon, sulfentrazone and flumioxazin. The interactions were additive for the weeds I. grandifolia and C. benghalensis but the herbicides flumioxazin, sulfentrazone and carfentrazone sprayed alone and in mixture with glyphosate gave better control results. The interaction of glyphosate with sulfentrazone was antagonic in R. brasiliensis, whereas the glyphosate mixed with other herbicides was additive; however, the treatments using glyphosate and chlorimuron-ethyl or flumioxazin were more efficient in weed control. In A. hybridus, the best control results were glyphosate and carfentrazone alone and glyphosate mixed with flumioxazin, sulfentrazone, chlorimuron-ethyl and bentazon, all additives. In the case of G. parviflora, flumioxazin, sulfentrazone, chlorimuron and bentazon with glyphosate and flumioxazin and sulfentrazone gave excellent control.

Monquero, P.A.; Christoffoleti, P.J.; Santos, C.T.D.

2001-12-01

243

Glyphosate em mistura com herbicidas alternativos para o manejo de plantas daninhas Glyphosate combined with alternative herbicides for vegetation management  

Directory of Open Access Journals (Sweden)

Full Text Available O uso intensivo de glyphosate como herbicida não-seletivo tem selecionado espécies de plantas daninhas tolerantes. Dessa forma, é importante que sejam estudadas misturas de tanque com herbicidas de mecanismos de ação alternativos e que apresentem efeitos sinergísticos ou aditivos. Por essa razão, foi instalado um experimento inteiramente casualizado, composto por 13 tratamentos e 4 repetições, em casa de vegetação da Universidade de São Paulo - ESALQ/USP, Piracicaba-SP, com as plantas daninhas Richardia brasiliensis, Commelina benghalensis, Amaranthus hybridus, Galinsoga parviflora e Ipomoea grandifolia em misturas de tanque dos herbicidas chlorimuron-ethyl, sulfentrazone, carfentrazone, bentazon ou flumioxazin com glyphosate. As interações foram aditivas para as plantas daninhas I. grandifolia e C. benghalensis, e os herbicidas flumioxazin, sulfentrazone e carfentrazone aplicados isoladamente e em mistura com glyphosate foram os que proporcionaram os melhores níveis de controle. A interação de glyphosate com sulfentrazone foi antagônica em R. brasiliensis; a mistura de glyphosate com os demais herbicidas estudados foi aditiva, sendo os tratamentos com mistura de glyphosate e chlorimuron-ethyl ou flumioxazin os mais eficazes. Em A. hybridus, os tratamentos que apresentaram melhores níveis de controle foram o glyphosate e carfentrazone, aplicados isoladamente, e a mistura de glyphosate com flumioxazin, sulfentrazone, chlorimuron-ethyl e bentazon, sendo estes interações aditivas. No caso de G. parviflora, os tratamentos com flumioxazin e sulfentrazone apresentaram controle total, o mesmo acontecendo com as misturas de glyphosate com carfentrazone, flumioxazin, sulfentrazone, chlorimuron-ethyl ou bentazon.The intensive use of glyphosate as a non-selective herbicide for weed vegetation management has selected some tolerant weed species. Thus, it is important to study the synergistic or antagonic or additive effects of tank mixtures of glyphosate combined with alternative mechanism of action herbicides. An experiment was developed in a randomized complete design, using 12 treatments and four replications, under greenhouse conditions at University of São Paulo - USP/ESALQ - Piracicaba-SP, Brazil, with the weeds Richardia brasiliensis, Commelina benghalensis, Amaranthus hybridus, Galinsoga parviflora and Ipomoea grandifolia and applying glyphosate combined with the herbicides chlorimuron-ethyl, carfentrazone, bentazon, sulfentrazone and flumioxazin. The interactions were additive for the weeds I. grandifolia and C. benghalensis but the herbicides flumioxazin, sulfentrazone and carfentrazone sprayed alone and in mixture with glyphosate gave better control results. The interaction of glyphosate with sulfentrazone was antagonic in R. brasiliensis, whereas the glyphosate mixed with other herbicides was additive; however, the treatments using glyphosate and chlorimuron-ethyl or flumioxazin were more efficient in weed control. In A. hybridus, the best control results were glyphosate and carfentrazone alone and glyphosate mixed with flumioxazin, sulfentrazone, chlorimuron-ethyl and bentazon, all additives. In the case of G. parviflora, flumioxazin, sulfentrazone, chlorimuron and bentazon with glyphosate and flumioxazin and sulfentrazone gave excellent control.

P.A. Monquero; P.J. Christoffoleti; C.T.D. Santos

2001-01-01

244

Weed control and yield are improved when glyphosate is preceded by a residual herbicide in glyphosate-tolerant maize (Zea mays)  

UK PubMed Central (United Kingdom)

In glyphosate-tolerant maize, a delay in glyphosate application may be required to ensure late germinating weeds do not reach reproductive maturity. Alternatively, full season weed control may be achieved by frequent applications of glyphosate throughout the growing season. Another approach that may improve weed control and aid in the stewardship of glyphosate use is to apply a pre-emergence residual herbicide prior to one in-crop application of glyphosate. There is limited information on the optimal glyphosate application timing in glyphosate-tolerant maize (Zea mays) following the application of a residual herbicide. Six factorial field trials were conducted over a 2 year period (1999 and 2000) at two Ontario locations, Ridgetown, and Woodstock to evaluate the efficacy of the residual herbicide flufenacet plus metribuzin applied preplant, pre-emergence or at the maize spike stage followed by a post-emergence application of glyphosate in glyphosate-tolerant maize. At Ridgetown, crop tolerance was acceptable at all flufenacet plus metribuzin, glyphosate and flufenacet plus metribuzin followed by glyphosate application timings. Visual crop injury of up to 40% was recorded at Woodstock after the application of flufenacet plus metribuzin. Control of Amaranthus retroflexus, Ambrosia artemisiifolia, and Chenopodium album with flufenacet plus metribuzin followed by an in-crop application of glyphosate was better than with one in-crop application of glyphosate. The application timing of glyphosate and flufenacet plus metribuzin was not a significant factor in weed control or grain yield. In maize, the application of a residual herbicide such as flufenacet plus metribuzin prior to glyphosate may provide better early season weed control and allow for the delayed in-crop application of glyphosate.

Nurse RE; Swanton CJ; Tardif F; Sikkema PH

2006-11-01

245

Toxic, cytotoxic, and genotoxic effects of a glyphosate formulation (Roundup®SL-Cosmoflux®411F) in the direct-developing frog Eleutherodactylus johnstonei.  

Science.gov (United States)

The aerial spraying of glyphosate formulations in Colombia to eradicate illegal crops has generated great concern about its possible impact on nontarget organisms, particularly amphibians. This study evaluated the toxic, cytotoxic, and genotoxic effects of a glyphosate formulation (Roundup®SL-Cosmoflux®411F) in the direct-developing frog Eleutherodactylus johnstonei by estimating the median lethal application rate (LC50 ), median hemolytic application rate (HD50 ), and extent of DNA damage using the in vitro and in vivo Comet assays. Toxicity results indicated that the application rate [37.4 µg acid equivalent (a.e.)/cm(2) ] equivalent to that used in aerial spraying (3.74 kg a.e./ha) is not lethal in male and female adult frogs, whereas neonates are highly sensitive. Glyphosate formulation at application rates above 5.4 µg a.e./cm(2) (in vivo) and concentrations above 95 µg a.e./mL (in vitro) showed clear evidence of cytotoxicity. In vivo and in vitro exposure of E. johnstonei erythrocytes to the glyphosate formulation induced DNA breaks in a dose-dependent manner with statistically significant values (P?glyphosate formulation. PMID:23625742

Meza-Joya, Fabio Leonardo; Ramírez-Pinilla, Martha Patricia; Fuentes-Lorenzo, Jorge Luis

2013-04-26

246

Toxic, cytotoxic, and genotoxic effects of a glyphosate formulation (Roundup®SL-Cosmoflux®411F) in the direct-developing frog Eleutherodactylus johnstonei.  

UK PubMed Central (United Kingdom)

The aerial spraying of glyphosate formulations in Colombia to eradicate illegal crops has generated great concern about its possible impact on nontarget organisms, particularly amphibians. This study evaluated the toxic, cytotoxic, and genotoxic effects of a glyphosate formulation (Roundup®SL-Cosmoflux®411F) in the direct-developing frog Eleutherodactylus johnstonei by estimating the median lethal application rate (LC50 ), median hemolytic application rate (HD50 ), and extent of DNA damage using the in vitro and in vivo Comet assays. Toxicity results indicated that the application rate [37.4 µg acid equivalent (a.e.)/cm(2) ] equivalent to that used in aerial spraying (3.74 kg a.e./ha) is not lethal in male and female adult frogs, whereas neonates are highly sensitive. Glyphosate formulation at application rates above 5.4 µg a.e./cm(2) (in vivo) and concentrations above 95 µg a.e./mL (in vitro) showed clear evidence of cytotoxicity. In vivo and in vitro exposure of E. johnstonei erythrocytes to the glyphosate formulation induced DNA breaks in a dose-dependent manner with statistically significant values (P?glyphosate formulation.

Meza-Joya FL; Ramírez-Pinilla MP; Fuentes-Lorenzo JL

2013-06-01

247

The occurrence of glyphosate, atrazine, and other pesticides in vernal pools and adjacent streams in Washington, DC, Maryland, Iowa, and Wyoming, 2005-2006  

Science.gov (United States)

Vernal pools are sensitive environments that provide critical habitat for many species, including amphibians. These small water bodies are not always protected by pesticide label requirements for no-spray buffer zones, and the occurrence of pesticides in them is poorly documented. In this study, we investigated the occurrence of glyphosate, its primary degradation product aminomethylphosphonic acid, and additional pesticides in vernal pools and adjacent flowing waters. Most sampling sites were chosen to be in areas where glyphosate was being used either in production agriculture or for nonindigenous plant control. The four site locations were in otherwise protected areas (e.g., in a National Park). When possible, water samples were collected both before and after glyphosate application in 2005 and 2006. Twenty-eight pesticides or pesticide degradation products were detected in the study, and as many as 11 were identified in individual samples. Atrazine was detected most frequently and concentrations exceeded the freshwater aquatic life standard of 1.8 micrograms per liter (??g/l) in samples from Rands Ditch and Browns Ditch in DeSoto National Wildlife Refuge. Glyphosate was measured at the highest concentration (328 ??g/l) in a sample from Riley Spring Pond in Rock Creek National Park. This concentration exceeded the freshwater aquatic life standard for glyphosate of 65 ??g/l. Aminomethylphosphonic acid, triclopyr, and nicosulfuron also were detected at concentrations greater than 3.0 ??g/l. ?? Springer Science+Business Media B.V. 2008.

Battaglin, W. A.; Rice, K. C.; Focazio, M. J.; Salmons, S.; Barry, R. X.

2009-01-01

248

CloudBurst: highly sensitive read mapping with MapReduce.  

UK PubMed Central (United Kingdom)

MOTIVATION: Next-generation DNA sequencing machines are generating an enormous amount of sequence data, placing unprecedented demands on traditional single-processor read-mapping algorithms. CloudBurst is a new parallel read-mapping algorithm optimized for mapping next-generation sequence data to the human genome and other reference genomes, for use in a variety of biological analyses including SNP discovery, genotyping and personal genomics. It is modeled after the short read-mapping program RMAP, and reports either all alignments or the unambiguous best alignment for each read with any number of mismatches or differences. This level of sensitivity could be prohibitively time consuming, but CloudBurst uses the open-source Hadoop implementation of MapReduce to parallelize execution using multiple compute nodes. RESULTS: CloudBurst's running time scales linearly with the number of reads mapped, and with near linear speedup as the number of processors increases. In a 24-processor core configuration, CloudBurst is up to 30 times faster than RMAP executing on a single core, while computing an identical set of alignments. Using a larger remote compute cloud with 96 cores, CloudBurst improved performance by >100-fold, reducing the running time from hours to mere minutes for typical jobs involving mapping of millions of short reads to the human genome. AVAILABILITY: CloudBurst is available open-source as a model for parallelizing algorithms with MapReduce at (http://cloudburst-bio.sourceforge.net/).

Schatz MC

2009-06-01

249

Preparation for glyphosate from N-(phosphonomethyl)iminodiacetic acid (PMIDA) and its products ,and related process  

UK PubMed Central (United Kingdom)

The present invention belongs to the field of herbicide technology, and is the process of preparing glyphosate with N-phosphonomethyl iminodiaacetic acid and compounding glyphosate products with glyphosate. Inside reactor, N-phosphonomethyl iminodiaacetic acid, hydrogen peroxide solution as oxidant and ferrous sulfate as reductant in the molar ratio of 1 to 2 to 3.6 produce oxidation and reduction at normal pressure to synthesize glyphosate proper amount of deionized water is added to obtain glyphosate aqua. The glyphosate aqua is used as main material to prepare marketable 10 % glyphosate aqua, 41 % glyphosate isopropyl amine salt solution, 95 % glyphosate powder, etc. The present invention has the features of short technological path, easily controlled reaction condition, high yield, low power consumption, etc.

MA XIHONG; ZHUANG MINGRU

250

High-performance liquid chromatographic determination of glyphosate and (aminomethyl)phosphonic acid in human serum after conversion into p-toluenesulphonyl derivatives.  

Science.gov (United States)

We have developed a simple, highly sensitive and fast assay method for determining glyphosate and its major metabolite, (aminomethyl)phosphonic acid (AMPA), in serum by high-performance liquid chromatography with ultraviolet detection. Both compounds were successfully extracted with an anion-exchange resin column and allowed to react with p-toluenesulphonyl chloride. The detection limits were 0.3 microgram/ml for glyphosate and 0.2 microgram/ml for AMPA. Recoveries of glyphosate and AMPA spiked to serum were ca. 75% and ca. 88%, respectively. We are convinced that this procedure, in practice, allows medical examiners to analyse both compounds in the serum of poisoned patients within a short time. PMID:1885717

Tomita, M; Okuyama, T; Watanabe, S; Uno, B; Kawai, S

1991-05-01

251

High-performance liquid chromatographic determination of glyphosate and (aminomethyl)phosphonic acid in human serum after conversion into p-toluenesulphonyl derivatives.  

UK PubMed Central (United Kingdom)

We have developed a simple, highly sensitive and fast assay method for determining glyphosate and its major metabolite, (aminomethyl)phosphonic acid (AMPA), in serum by high-performance liquid chromatography with ultraviolet detection. Both compounds were successfully extracted with an anion-exchange resin column and allowed to react with p-toluenesulphonyl chloride. The detection limits were 0.3 microgram/ml for glyphosate and 0.2 microgram/ml for AMPA. Recoveries of glyphosate and AMPA spiked to serum were ca. 75% and ca. 88%, respectively. We are convinced that this procedure, in practice, allows medical examiners to analyse both compounds in the serum of poisoned patients within a short time.

Tomita M; Okuyama T; Watanabe S; Uno B; Kawai S

1991-05-01

252

Glyphosate formulations with early burndown symptoms  

UK PubMed Central (United Kingdom)

Disclosed is an aqueous ready-to-use herbicidal composition comprising: between 0.1-5% by weight (a.e.) of a glyphosate component comprising N-(phosphonomethyl)glycine, an agronomically acceptable salt of N-(phosphonomethyl)glycine or a mixture thereof between 1.5-5% by weight (a.e.) of a fatty acid component predominantly comprising at least one C8 to C12 saturated, straight or branched chain fatty acid or an agronomically acceptable salt thereof and between 0.5-4% by weight of an agronomically acceptable inorganic ammonium salt. Preferred combinations include pelargonic acid as the fatty acid, and ammonium sulfate as the ammonium salt.

WRIGHT DANIEL R; SANDBRINK JOSEPH J; RATLIFF PAUL G; KLIEWER BRYAN A; WYSE-PESTER DAWN Y

253

Adsorption of glyphosate and aminomethylphosphonic acid in soils  

Science.gov (United States)

The results showed that glyphosate is initially adsorbed mostly in the upper 2 cm. It is than transported and adsorbed after few days in deeper soil horizons with concomitant increasing content of its metabolite aminomethylphosphonic acid. Moreover, Fe-oxides seem to be a key parameter for glyphosate and aminomethylphosphonic adsorption in soils. This study confirmed previous studies: the analysis showed lower contents of dithionite-soluble and Fe-oxides for the Chernozem, with consequently lower adsorption of glyphosate and aminomethylphosphonic as compared with the Cambisol and the Stagnosol.

Rampazzo, N.; Rampazzo Todorovic, G.; Mentler, A.; Blum, W. E. H.

2013-03-01

254

Glyphosate management strategies, weed diversity and soybean yield in Argentina  

UK PubMed Central (United Kingdom)

From their introduction in 1996, glyphosate resistant (GR) soybean cultivars have been rapidly adopted by farmers in Argentina and in other countries in the world. The high rate of adoption of this technology seems to be based on the simplicity of use provided by a single herbicide (glyphosate), its high efficacy to control many weeds and, the low costs of the technology relative to that used in conventional crops. During 2001-2002, 2002-2003 and 2003-2004 soybean growing seasons, field surveys and field experiments were performed with the aim of studying the effect of different glyphosate management strategies on the diversity of soybean weed communities, weed control, individual survival, fecundity and crop yield. In addition, the emergence pattern of three important weeds, Digitaria sanguinalis, Cyperus rotundus and Anoda cristata, was also studied. Both field surveys and field experiments were carried out on no-till soybean crops sown immediately after wheat or barley harvest (double cropped system). Experiments were set up in commercial soybean crops and consisted of different times of a single glyphosate application, two glyphosate applications and also the application of glyphosate plus a residual herbicide imazethapyr. A. cristata, D. sanguinalis, Stellaria media, Chenopodium album and Cyperus sp. were the most prevalent weeds recorded at pre-harvest of the soybean crops, showing regional constancy higher than 80% in both years. In three out of four field experiments, crop yield was not increased when glyphosate was applied twice compared with a single application of the herbicide. In addition there was a lower negative effect on weed species richness when glyphosate was applied once during the crop cycle than with two applications of glyphosate or glyphosate plus imazethapyr. D. sanguinalis escaped the glyphosate early treatment because of the long weed emergence period, while A. cristata and C. rotundus survived treatments due to their high individual tolerance. The results suggest that it is possible to manage glyphosate application to get high crop yield with a low impact on weed diversity, depending on the weed species and their abundance.

Scursoni JA; Satorre EmilioH

2010-09-01

255

Highly sensitive micromachined capacitive pressure sensor with reduced hysteresis and low parasitic capacitance  

DEFF Research Database (Denmark)

This paper describes the design and fabrication of a capacitive pressure sensor that has a large capacitance signal and a high sensitivity of 76 pF/bar in touch mode operation. Due to the large signal, problems with parasitic capacitances are avoided and hence it is possible to integrate the sensor with a discrete components electronics circuit for signal conditioning. Using an AC bridge electronics circuit a resolution of 8 mV/mbar is achieved. The large signal is obtained due to a novel membrane structure utilizing closely packed hexagonal elements. The sensor is fabricated in a process based on fusion bonding to create vacuum cavities. The exposed part of the sensor is perfectly flat such that it can be coated with corrosion resistant thin films. Hysteresis is an inherent problem in touch mode capacitive pressure sensors and a technique to significantly reduce it is presented.

Pedersen, Thomas; Fragiacomo, Giulio

2009-01-01

256

Resistência de Conyza canadensis e C. bonariensis ao herbicida glyphosate/ Glyphosate-resistance in Conyza canadensis and C. bonariensis  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O objetivo deste trabalho foi avaliar, por meio de curvas de dose-resposta, a ocorrência de biótipos resistentes ao herbicida glyphosate em populações de Conyza canadensis e C. bonariensis, bem como propor tratamentos alternativos para esses biótipos. Os experimentos foram realizados em casa de vegetação, utilizando-se três populações de cada espécie: duas com suspeita de resistência ao herbicida glyphosate, coletadas em pomares de laranja localizados em duas (more) regiões diferentes do Estado de São Paulo; e uma suscetível, coletada em área sem histórico de aplicação do herbicida. O delineamento experimental adotado foi o de blocos ao acaso, com quatro repetições. Para cada espécie, os tratamentos foram resultado da combinação fatorial entre as três populações e os tratamentos herbicidas (oito doses de glyphosate ou cinco tratamentos alternativos). As doses de glyphosate foram (g e.a. ha¹): 90, 180, 360, 720, 1.440, 2.880, 5.760 e testemunha sem aplicação. Como alternativas de controle, foram testados os seguintes tratamentos (g ha-1): glyphosate + 2,4-D (1.440 + 1.005), glyphosate + metsulfuron (1.440 + 2,4), glyphosate + metsulfuron (1.440 + 3,6), glyphosate + metribuzin (1.440 + 480) e testemunha sem aplicação. A partir dos resultados, comprovou-se a existência de populações de ambas as espécies com biótipos resistentes ao herbicida glyphosate, com diferentes níveis de resistência. Todos os tratamentos herbicidas alternativos controlaram de forma eficiente as três populações de cada espécie. Abstract in english The objective of this research was to evaluate, through dose-response curves, the occurrence of glyphosate-resistant biotypes in populations of Conyza canadensis and C. bonariensis; as well as to propose alternative treatments to these biotypes. The experiments were conducted in a greenhouse, using three populations of each species: two with suspicion of resistance to the herbicide glyphosate, and collected in orange orchards located in two different São Paulo state regi (more) ons; and a susceptible one, collected in an area without herbicide application history. The experimental design adopted was randomized blocks, with four replicates. For each species, the treatments were the result of a factorial combination among the three populations and the herbicide treatments (eight rates of glyphosate or five alternative treatments). The glyphosate rates used were (g e.a. ha-1): 90, 180, 360, 720, 1.440, 2.880, 5.760 and checks without application. As control alternative, the following treatments (g ha-1) were tested: glyphosate + 2,4-D (1.440 + 1.005), glyphosate + metsulfuron (1.440 + 2,4), glyphosate + metsulfuron (1.440 + 3,6), glyphosate + metribuzin (1440 + 480) and checks without application. The results obtained proved the existence of populations of both species with glyphosate-resistant biotypes, with different levels of resistance. All the alternative herbicide treatments controlled efficiently the three populations of each species.

Moreira, M.S.; Nicolai, M.; Carvalho, S.J.P.; Christoffoleti, P.J.

2007-03-01

257

Resistência de Conyza canadensis e C. bonariensis ao herbicida glyphosate Glyphosate-resistance in Conyza canadensis and C. bonariensis  

Directory of Open Access Journals (Sweden)

Full Text Available O objetivo deste trabalho foi avaliar, por meio de curvas de dose-resposta, a ocorrência de biótipos resistentes ao herbicida glyphosate em populações de Conyza canadensis e C. bonariensis, bem como propor tratamentos alternativos para esses biótipos. Os experimentos foram realizados em casa de vegetação, utilizando-se três populações de cada espécie: duas com suspeita de resistência ao herbicida glyphosate, coletadas em pomares de laranja localizados em duas regiões diferentes do Estado de São Paulo; e uma suscetível, coletada em área sem histórico de aplicação do herbicida. O delineamento experimental adotado foi o de blocos ao acaso, com quatro repetições. Para cada espécie, os tratamentos foram resultado da combinação fatorial entre as três populações e os tratamentos herbicidas (oito doses de glyphosate ou cinco tratamentos alternativos). As doses de glyphosate foram (g e.a. ha¹): 90, 180, 360, 720, 1.440, 2.880, 5.760 e testemunha sem aplicação. Como alternativas de controle, foram testados os seguintes tratamentos (g ha-1): glyphosate + 2,4-D (1.440 + 1.005), glyphosate + metsulfuron (1.440 + 2,4), glyphosate + metsulfuron (1.440 + 3,6), glyphosate + metribuzin (1.440 + 480) e testemunha sem aplicação. A partir dos resultados, comprovou-se a existência de populações de ambas as espécies com biótipos resistentes ao herbicida glyphosate, com diferentes níveis de resistência. Todos os tratamentos herbicidas alternativos controlaram de forma eficiente as três populações de cada espécie.The objective of this research was to evaluate, through dose-response curves, the occurrence of glyphosate-resistant biotypes in populations of Conyza canadensis and C. bonariensis; as well as to propose alternative treatments to these biotypes. The experiments were conducted in a greenhouse, using three populations of each species: two with suspicion of resistance to the herbicide glyphosate, and collected in orange orchards located in two different São Paulo state regions; and a susceptible one, collected in an area without herbicide application history. The experimental design adopted was randomized blocks, with four replicates. For each species, the treatments were the result of a factorial combination among the three populations and the herbicide treatments (eight rates of glyphosate or five alternative treatments). The glyphosate rates used were (g e.a. ha-1): 90, 180, 360, 720, 1.440, 2.880, 5.760 and checks without application. As control alternative, the following treatments (g ha-1) were tested: glyphosate + 2,4-D (1.440 + 1.005), glyphosate + metsulfuron (1.440 + 2,4), glyphosate + metsulfuron (1.440 + 3,6), glyphosate + metribuzin (1440 + 480) and checks without application. The results obtained proved the existence of populations of both species with glyphosate-resistant biotypes, with different levels of resistance. All the alternative herbicide treatments controlled efficiently the three populations of each species.

M.S. Moreira; M. Nicolai; S.J.P. Carvalho; P.J. Christoffoleti

2007-01-01

258

Reduced stretch-reflex sensitivity after exhausting stretch-shortening cycle exercise.  

UK PubMed Central (United Kingdom)

The stretch-shortening cycle (SSC) is an effective and natural form of muscle function but, when repeated with sufficient intensity or duration, it may lead to muscle damage and functional defects. A reduced tolerance to impact has been reported, which may be partly attributed to a reduced stretch-reflex potentiation. The aim of the present study was to examine the influence of SSC-induced metabolic fatigue and muscle damage on the efficacy of stretch reflexes, as judged by the electromyograph (EMG) response of two shank muscles (lateral gastrocnemius LG, soleus SOL) to controlled ramp stretches. These EMG responses were recorded before and immediately after exhausting SSC-type leg exercise and 2 h, 2 days and 4 days later. Serum concentrations of creatine kinase ([CK]), myoglobin and lactate were measured repetitively along the protocol. Two maximal vertical drop jumps and counter-movement jumps were performed after each reflex test. The exhausting SSC-type exercise induced an immediate reduction (P < 0.05) with a delayed short-term recovery of the LG peak-to-peak reflex amplitude. This was not accompanied by significant changes in the reflex latency. The drop jump performance remained slightly but significantly reduced (P < 0.05) until the 2nd day postexercise. Peak [CK] appeared for all the subjects on the 2nd day, suggesting the presence of muscle damage. The increase in [CK] between the 2nd h and the 2nd day postexercise was found to be negatively related (P < 0.001) to the relative changes in the drop jump height. Furthermore, a significant relationship (P < 0.05) was found between recovery of the stretch reflex in LG and the decrease of [CK] between the 2nd and the 4th day. These findings support the hypothesis of a reduced stretch-reflex sensitivity. While the exact mechanisms of the reflex inhibition remain unclear, it is emphasized that the delayed recovery of the reflex sensitivity could have resulted from the progressive inflammation that develops in cases of muscle damage.

Nicol C; Komi PV; Horita T; Kyröläinen H; Takala TE

1996-01-01

259

Reduced sensitizing capacity of epoxy resin systems: a structure-activity relationship study.  

Science.gov (United States)

Epoxy resins can be prepared from numerous chemical compositions. Until recently, alternatives to epoxy resins based on diglycidyl ethers of bisphenol A (DGEBA) or bisphenol F (DGEBF) monomers have not received commercial interest, but are presently doing so, as epoxy resins with various properties are desired. Epoxy resin systems are known to cause allergic contact dermatitis because of contents of uncured monomers, reactive diluents, and hardeners. Reactive diluents, for example, glycidyl ethers, which also contain epoxide moieties, are added to reduce viscosity and improve polymerization. We have investigated the contact allergenic properties of a series of six analogues to phenyl glycidyl ether (PGE), all with similar basic structures but with varying carbon chain lengths and degrees of saturation. The chemical reactivity of the compounds in the test series toward the hexapeptide H-Pro-His-Cys-Lys-Arg-Met-OH was investigated. All epoxides were shown to bind covalently to both cysteine and proline residues. The percent depletion of nonreacted peptide was also studied resulting in 88% depletion when using PGE and 46% when using butyl glycidyl ether (5) at the same time point, thus revealing a large difference between the fastest and the slowest reacting epoxide. The skin sensitization potencies of the epoxides using the murine local lymph node assay (LLNA) were evaluated in relation to the observed physicochemical and reactivity properties. To enable determination of statistical significance between structurally closely related compounds, a nonpooled LLNA was performed. It was found that the compounds investigated ranged from strong to weak sensitizers, congruent with the reactivity data, indicating that even small changes in chemical structure result in significant differences in sensitizing capacity. PMID:19725531

Niklasson, Ida B; Broo, Kerstin; Jonsson, Charlotte; Luthman, Kristina; Karlberg, Ann-Therese

2009-11-01

260

Reduced sensitivity of the ferroportin Q248H mutant to physiological concentrations of hepcidin.  

UK PubMed Central (United Kingdom)

Ferroportin Q248H mutation has an allele frequency of 2.2-13.4% in African populations and is associated with a mild tendency to increased serum ferritin in the general population. Some investigators have reported that ferroportin Q248H is degraded after exposure to hepcidin in exactly the same manner as wild-type ferroportin, but supraphysiological concentrations of hepcidin were used. The aim of our study was to determine whether ferroportin Q248H may have reduced sensitivity to physiological concentrations of hepcidin. The sensitivity of ferroportin Q248H to hepcidin was determined in 293T cells transiently expressing ferroportin using immunoblotting and fluorescence analysis. Ferritin concentrations were measured in these cells and also in human primary monocytes derived from humans with different ferroportin genotypes. The effect of Q248H on serum iron measures was examined in patients with sickle cell anemia. Immunoblotting and fluorescence analysis showed decreased sensitivity of ferroportin Q248H to physiological concentrations of hepcidin. Lower ferritin concentrations were observed after incubation with iron and hepcidin in 293T cells expressing ferroportin Q248H and in primary monocytes from ferroportin Q248H subjects. In sickle cell anemia, ferroportin Q248H heterozygotes had lower serum ferritin concentrations than wild-type subjects, consistent with enhanced iron release by macrophage ferroportin Q248H. A clinical benefit of ferroportin Q248H was suggested by lower echocardiographic estimates of pulmonary artery pressure in patients carrying mutant alleles. In conclusion, our results suggest that ferroportin Q248H protein is resistant to physiological concentrations of hepcidin and that this mutation has discernible effects on iron metabolism-related clinical complications of sickle cell anemia. They provide a mechanistic explanation for the effect of ferroportin Q248H on iron status in individuals of African descent and suggest that these changes in iron metabolism may be beneficial under certain disease-specific circumstances. (ClinicalTrials.gov Identifier:NCT00011648).

Nekhai S; Xu M; Foster A; Kasvosve I; Diaz S; Machado RF; Castro OL; Kato GJ; Taylor JG 6th; Gordeuk VR

2013-03-01

 
 
 
 
261

Sensitive detection of rutin based on ?-cyclodextrin-chemically reduced graphene/Nafion composite film  

International Nuclear Information System (INIS)

Highlights: ? ?-CD-graphene composite obtained via a simple sonication-induced assembly. ? Accelerating electron transfer on electrode to amplify the electrochemical signal. ? A highly sensitive electrochemical sensor for rutin detection. ? Good selectivity and reproducibility for the detection of rutin in real samples. - Abstract: An electrochemical sensor based on chemically reduced graphene (CRG) was developed for the sensitive detection of rutin. To construct the base of the sensor, a novel composite was initially fabricated and used as the substrate material by combining CRG and ?-cyclodextrin (?-CD) via a simple sonication-induced assembly. Due to the high rutin-loading capacity on the electrode surface and the upstanding electric conductivity of graphene, the electrochemical response of the fabricated sensor was greatly enhanced and displayed excellent analytical performance for rutin detection from 6.0 x 10-9 to 1.0 x 10-5 mol L-1 with a low detection limit of 2.0 x 10-9 mol L-1 at 3?. Moreover, the proposed electrochemical sensor also exhibited good selectivity and acceptable reproducibility and could be used for the detection of rutin in real samples. Therefore, the present work offers a new way to broaden the analytical applications of graphene in pharmaceutical analysis.

2011-05-30

262

Sensitive detection of rutin based on {beta}-cyclodextrin-chemically reduced graphene/Nafion composite film  

Energy Technology Data Exchange (ETDEWEB)

Highlights: > {beta}-CD-graphene composite obtained via a simple sonication-induced assembly. > Accelerating electron transfer on electrode to amplify the electrochemical signal. > A highly sensitive electrochemical sensor for rutin detection. > Good selectivity and reproducibility for the detection of rutin in real samples. - Abstract: An electrochemical sensor based on chemically reduced graphene (CRG) was developed for the sensitive detection of rutin. To construct the base of the sensor, a novel composite was initially fabricated and used as the substrate material by combining CRG and {beta}-cyclodextrin ({beta}-CD) via a simple sonication-induced assembly. Due to the high rutin-loading capacity on the electrode surface and the upstanding electric conductivity of graphene, the electrochemical response of the fabricated sensor was greatly enhanced and displayed excellent analytical performance for rutin detection from 6.0 x 10{sup -9} to 1.0 x 10{sup -5} mol L{sup -1} with a low detection limit of 2.0 x 10{sup -9} mol L{sup -1} at 3{sigma}. Moreover, the proposed electrochemical sensor also exhibited good selectivity and acceptable reproducibility and could be used for the detection of rutin in real samples. Therefore, the present work offers a new way to broaden the analytical applications of graphene in pharmaceutical analysis.

Liu Kunping; Wei Jinping [School of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Wang Chunming, E-mail: wangcm@lzu.edu.cn [School of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

2011-05-30

263

Labile compounds in plant litter reduce the sensitivity of decomposition to warming and altered precipitation.  

Science.gov (United States)

Together, climate and litter quality strongly regulate decomposition rates. Although these two factors and their interaction have been studied across species in continent-scale experiments, few researchers have studied how labile and recalcitrant compounds interact to influence decomposition, or the climate sensitivity of decomposition, within a litter type. Over a period of 3 yr, we studied the effects of warming and altered precipitation on mass loss and compound-specific decomposition using two litter types that possessed similar heteropolymer chemistry, but different proportions of labile and recalcitrant compounds. Climate treatments immediately affected the mass loss of the more recalcitrant litter, but affected the more labile litter only after 2 yr. After 3 yr, although both litter types had lost similar amounts of mass, warming (c. 4°C) and supplemental precipitation (150% of ambient) together accelerated the degradation of alkyl-carbon and lignin only in the more recalcitrant litter, highlighting the role of initial litter quality in determining whether the chemistry of litter residues converges or diverges under different climates. Our finding that labile compounds in litter reduce the climate sensitivity of mass loss and the decomposition of recalcitrant matrix is novel. Our results highlight the potential for litter quality to regulate the effect of climatic changes on the sequestration of litter-derived carbon. PMID:23822593

Suseela, Vidya; Tharayil, Nishanth; Xing, Baoshan; Dukes, Jeffrey S

2013-07-04

264

Labile compounds in plant litter reduce the sensitivity of decomposition to warming and altered precipitation.  

UK PubMed Central (United Kingdom)

Together, climate and litter quality strongly regulate decomposition rates. Although these two factors and their interaction have been studied across species in continent-scale experiments, few researchers have studied how labile and recalcitrant compounds interact to influence decomposition, or the climate sensitivity of decomposition, within a litter type. Over a period of 3 yr, we studied the effects of warming and altered precipitation on mass loss and compound-specific decomposition using two litter types that possessed similar heteropolymer chemistry, but different proportions of labile and recalcitrant compounds. Climate treatments immediately affected the mass loss of the more recalcitrant litter, but affected the more labile litter only after 2 yr. After 3 yr, although both litter types had lost similar amounts of mass, warming (c. 4°C) and supplemental precipitation (150% of ambient) together accelerated the degradation of alkyl-carbon and lignin only in the more recalcitrant litter, highlighting the role of initial litter quality in determining whether the chemistry of litter residues converges or diverges under different climates. Our finding that labile compounds in litter reduce the climate sensitivity of mass loss and the decomposition of recalcitrant matrix is novel. Our results highlight the potential for litter quality to regulate the effect of climatic changes on the sequestration of litter-derived carbon.

Suseela V; Tharayil N; Xing B; Dukes JS

2013-10-01

265

New C$_{6}$D$_{6}$ detectors: reduced neutron sensitivity and improved safety  

CERN Document Server

During the 2011 data measurement campaign at n_TOF, the liquid scintillator detectors developed at FZK-Karlsruhe (hereafter named K6D6, [1]) and used with success along 10 years have shown ageing problems, mainly related to liquid leakage. The mould used to produce the carbon fiber structure, containing the liquid and the detection elements, was not available anymore and the technician involved in its construction was retired. Once decided to proceed to the production of new detectors (L6D6 in the following) two major items have been identified: - The detector setup must be able to work in the new class A experimental area (safety requirements advise to avoid the use of the old K6D6 in this area). - If possible, it is useful to reduce the neutron sensitivity, with the aim to have a liquid scintillator detector with very low neutron sensitivity (improving the already high performing K6D6). [1] R.Plag et al., NIM A496 (2003) 425

Mastinu, Pierfrancesco; Berthoumieux, Eric; Cano-Ott, Daniel; Gramegna, F; Guerrero, Carlos; Massimi, Cristian; Milazzo, Paolo Maria; Mingrone, Federica; Praena, Javier; Prete, G; García, Aczel Regino

2013-01-01

266

Efeito hormese de glyphosate em feijoeiro/ Hormesis effect of glyphosate on common bean cultivars  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Embora o efeito hormese seja amplamente conhecido, ainda não tem aplicação prática definida para o desenvolvimento da tecnologia agropecuária. Desta forma, propôs-se um estudo, no município de Selvíria (MS), com o objetivo de verificar o efeito da aplicação de baixas doses do herbicida glyphosate (0 g ha-1, 10 g ha-1, 20 g ha-1, 30 g ha-1 e 40 g ha-1 do ingrediente ativo) no desenvolvimento e produtividade de cultivares de feijão (Carioca precoce - tipo I, Juri (more) ti - tipo II e Pérola - tipo III) irrigadas por aspersão, no outono-inverno de 2009 e 2010. O delineamento experimental foi em blocos casualizados, com 15 tratamentos dispostos em esquema fatorial 5x3 e quatro repetições. Concluiu-se que a massa de 100 grãos foi reduzida, quando submetida a subdoses mais elevadas de glyphosate, e que a aplicação de subdoses de glyphosate não alterou a produtividade do feijoeiro, quando avaliadas as três cultivares conjuntamente, entretanto, quando cada cultivar foi analisada individualmente, verificou-se aumento na produtividade do feijoeiro de até 10%, para a cultivar Juriti. Abstract in english Although being well-known, the hormesis effect has not yet a defined practical application on the development of agricultural technology. Thus, this study was carried out in Selvíria, Mato Grosso do Sul State, Brazil, in order to evaluate the effect of glyphosate applied at low doses (0 g ha-1, 10 g ha-1, 20 g ha-1, 30 g ha-1 and 40 g ha-1 of active ingredient) on the development and yield of bean cultivars (Carioca precoce - type I, Juriti - type II and Pérola - type I (more) II), irrigated by aspersion, in the autumn/winter of 2009 and 2010. The experimental design was randomized blocks, with 15 treatments arranged in a 5x3 factorial scheme and four replications. It was possible to conclude that the 100 grains mass decreased when submitted to higher glyphosate sub doses, and that the application of glyphosate sub doses did not affect the common bean yield, when the three cultivars were evaluated altogether, however, when each cultivar was individually analyzed, an increase of up to 10% in yield was observed for the Juriti cultivar.

Silva, Juliano Costa da; Arf, Orivaldo; Gerlach, Gustavo Antonio Xavier; Kuryiama, Clarice Sayumi; Rodrigues, Ricardo Antonio Ferreira

2012-09-01

267

Deriva simulada de glyphosate em algodoeiro: efeito de dose, cultivar e estádio de desenvolvimento Simulated drift of glyphosate in cotton crop: dose effect, cultivation and development levels  

Directory of Open Access Journals (Sweden)

Full Text Available Objetivou-se com este trabalho avaliar os efeitos da deriva simulada, pela aplicação de doses reduzidas de glyphosate em diferentes cultivares e estádios de desenvolvimento do algodoeiro. O ensaio foi realizado a campo em Alta Floresta, MT. As doses reduzidas de glyphosate foram 0, 180 e 360 g e.a. ha-1. Os cultivares ITA-90 e BRS-Facual foram tratados nos estádios de quatro e dez folhas. Foram avaliados aos 7, 14, 28, 42, 56 e 70 dias: sintomas visuais de intoxicação e altura de planta. Ao final do ensaio, foi avaliado o rendimento de algodão em caroço. Plantas de algodão tratadas com a dose de 180 g ha-1 apresentaram recuperação lenta, não havendo diferença entre os estádios de desenvolvimento. A maior dose provocou maiores danos em plantas mais jovens. O algodoeiro tratado com a menor dose apresentou crescimento normal nos 70 dias após a aplicação; quando tratado com 360 g ha-1, o crescimento foi afetado, principalmente em plantas mais jovens, e os sintomas visuais de intoxicação nas folhas foram mais severos em plantas mais jovens, havendo recuperação classificada como aceitável em plantas mais velhas. Houve redução no rendimento de algodão em caroço em todos os tratamentos, exceto em plantas mais velhas tratadas com 180 g ha-1.This work aimed to evaluate the effects of reduced rates of simulated drift of glyphosate on cotton crop using different cultivars and development levels. The assay was carried out in Alta Floresta, MT. The reduced doses of glyphosate were 0,180 and 360 g a.e. ha-1. The cultivars ITA-90 and BRS-Facual were treated at the four and 10 leaf stages and phytotoxicity visual symptoms and plant height were assessed at 7,14,28,42,56 and 70 days. At the end of the trial, cotton yield and seed quality were evaluated. Cotton plant treated with 180 g ha-1 dose had a slow recovery, with no difference being observed between the development levels. The highest dose caused greater damages in younger plants. The cotton plant treated with the smallest dose presented a normal growth 70 days after application but when the dose of 360 g ha-1 was applied, growth was affected, especially in younger plants, and the visual symptoms of phytotoxicity in the leaves were more severe in younger plants, with recovery classified as acceptable in older plants .Cotton yield was reduced in all treatments, except in older plants treated with 180 g ha-1 e.a.

O.M. Yamashita; S.C. Guimarães

2006-01-01

268

Regional differences in time to pregnancy among fertile women from five Colombian regions with different use of glyphosate.  

UK PubMed Central (United Kingdom)

The objective of this study was to test whether there was an association between the use of glyphosate when applied by aerial spray for the eradication of illicit crops (cocaine and poppy) and time to pregnancy (TTP) among fertile women. A retrospective cohort study (with an ecological exposure index) of first pregnancies was undertaken in 2592 fertile Colombian women from 5 regions with different uses of glyphosate. Women were interviewed regarding potential reproductive, lifestyle, and work history predictors of TTP, which was measured in months. Fecundability odds ratios (fOR) were estimated using a discrete time analogue of Cox's proportional hazard model. There were differences in TTP between regions. In the final multivariate model, the main predictor was the region adjusted by irregular relationship with partner, maternal age at first pregnancy, and, marginally, coffee consumption and self-perception of water pollution. Boyaca, a region with traditional crops and. recently, illicit crops without glyphosate eradication spraying (manual eradication), displayed minimal risk and was the reference region. Other regions, including Sierra Nevada (control area, organic agriculture), Putumayo and Narino (illicit crops and intensive eradication spray program), and Valle del Cauca, demonstrated greater risk of longer TTP, with the highest risk for Valle del Cauca (fOR 0.15, 95% CI 0.12, 0.18), a sugar-cane region with a history of use of glyphosate and others chemicals for more than 30 yr. The reduced fecundability in some regions was not associated with the use of glyphosate for eradication spraying. The observed ecological differences remain unexplained and may be produced by varying exposures to environmental factors, history of contraceptive programs in the region, or psychological distress. Future studies examining these or other possible causes are needed.

Sanin LH; Carrasquilla G; Solomon KR; Cole DC; Marshall EJ

2009-01-01

269

[Effect of glyphosate on the energy exchange in carp organs].  

UK PubMed Central (United Kingdom)

The use of glyphosate as a herbicide in agriculture can lead to the presence of its residues and metabolites (aminomethylphosphonic acid) in food for human consumption and pose a threat to health. The effect of these herbicides on the fish organism at the biochemical level has been insufficiently studied. We studied changes in the content of adenine nucleotides, enzyme activity, quantitative indexes of energy metabolism substrates in carp under the action of glyphosate. It has been found that proteins are the major energy substrate under the influence of glyphosate in the liver, brain, white muscle of carp yearlings. Glyphosphate decreases energy metabolism in the brain of carp and increases it in the white muscles. The growth of activity of catabolic enzymes in the liver under the influence of glyphosate can be attributed to the adaptive remodelling of metabolic pathways for homeostasis and enantiostasis in response to herbicides.

Zhidenko AA; Bibchuk EV; Barbukho EV

2013-05-01

270

[Effect of glyphosate on the energy exchange in carp organs].  

Science.gov (United States)

The use of glyphosate as a herbicide in agriculture can lead to the presence of its residues and metabolites (aminomethylphosphonic acid) in food for human consumption and pose a threat to health. The effect of these herbicides on the fish organism at the biochemical level has been insufficiently studied. We studied changes in the content of adenine nucleotides, enzyme activity, quantitative indexes of energy metabolism substrates in carp under the action of glyphosate. It has been found that proteins are the major energy substrate under the influence of glyphosate in the liver, brain, white muscle of carp yearlings. Glyphosphate decreases energy metabolism in the brain of carp and increases it in the white muscles. The growth of activity of catabolic enzymes in the liver under the influence of glyphosate can be attributed to the adaptive remodelling of metabolic pathways for homeostasis and enantiostasis in response to herbicides. PMID:23937045

Zhidenko, A A; Bibchuk, E V; Barbukho, E V

271

Resistência de genótipos de soja ao herbicida glyphosate Resistance of soybean genotypes to glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available Avaliou-se a resistência de dez genótipos de soja (Glycine max) ao herbicida glyphosate. Foi adotado o esquema fatorial 10 x 4, no delineamento em blocos casualizados, com quatro repetições. O fator A foi composto por dez genótipos de soja, e o B, por quatro doses de glyphosate. A aplicação do herbicida foi realizada no momento em que as plantas de soja apresentavam a segunda folha trifoliolada completamente desenvolvida. Avaliaramse os caracteres: intoxicação das plantas, número de nós da haste principal, altura das plantas e massa seca das plantas. Na avaliação da intoxicação de plantas, tanto aos quatro dias após a aplicação (DAA) do herbicida quanto aos 28 DAA, os genótipos convencionais apresentaram médias superiores estatisticamente em comparação com genótipos resistentes ao glyphosate (RR). Verificou-se que, nas avaliações realizadas ao 0 DAA ou aos 28 DAA sob 0,0 g e.a. ha¹, as respostas dos genótipos foram diferentes em todos os caracteres avaliados, com exceção do número de nós aos 28 DAA. Essas diferenças podem ser atribuídas aos efeitos fisiológicos e ambientais ou a características do próprio material. Nas demais doses, os genótipos RR comportaram-se de maneira desejável em detrimento dos genótipos convencionais. Ao considerar todos os caracteres avaliados, pode-se afirmar que Valiosa RR, BCR945G110, BCR945G114, BCR892G132, BCR892G140, BCR1067G210, BCR1070G244 e M-SOY 8008RR comportaram-se de forma semelhante quanto à resistência ao glyphosate quando submetidos até a dose de 2.160 g e.a. ha-1 .Resistance of ten soybean genotypes (Glycine max) to the herbicide glyphosate was evaluated. The randomized block experimental design was used under factorial scheme 10 x 4 and four replicates. Factor A was composed of 10 soybean genotypes and factor B of four glyphosate doses. The herbicide was applied when the second trifoliate leaf of the soybean plants was completely developed. The following characters were evaluated: plant intoxication, number of nodes at the main stem, plant height and dry mass. When evaluating plant intoxication either at four days after application (DAA) of the herbicide and at 28 DAA, the conventional genotypes showed statistically higher averages, compared to the glyphosate-resistant genotypes (RR). In evaluations accomplished at 0 DAA or at 28 DAA under 0.0 g e.a. ha-1, the genotype responses were different for all characters under evaluation, except for the number of nodes at 28 DAA. These differences were attributed to the physiological and environmental effects or to the characteristics of the material itself. At other doses, the behavior of the RR genotypes was superior to that of the conventional ones. Taking into account all characters under evaluation, it can be stated that Valiosa RR, BCR945G110, BCR945G114, BCR892G132, BCR892G140, BCR1067G210, BCR1070G244 and M-SOY 8008RR behaved similarly for glyphosate resistance when subjected to doses up to 2.160 g e.a. ha-1 .

E Matsuo; T Sediyama; C.D Cruz; A.A Silva; R.C.T Oliveira; A.P.O Nogueira; F.D Tancredi

2009-01-01

272

Glyphosate-resistant weeds of South American cropping systems: an overview.  

Science.gov (United States)

Herbicide resistance is an evolutionary event resulting from intense herbicide selection over genetically diverse weed populations. In South America, orchard, cereal and legume cropping systems show a strong dependence on glyphosate to control weeds. The goal of this report is to review the current knowledge on cases of evolved glyphosate-resistant weeds in South American agriculture. The first reports of glyphosate resistance include populations of highly diverse taxa (Lolium multiflorum Lam., Conyza bonariensis L., C. canadensis L.). In all instances, resistance evolution followed intense glyphosate use in fruit fields of Chile and Brazil. In fruit orchards from Colombia, Parthenium hysterophorus L. has shown the ability to withstand high glyphosate rates. The recent appearance of glyphosate-resistant Sorghum halepense L. and Euphorbia heterophylla L. in glyphosate-resistant soybean fields of Argentina and Brazil, respectively, is of major concern. The evolution of glyphosate resistance has clearly taken place in those agroecosystems where glyphosate exerts a strong and continuous selection pressure on weeds. The massive adoption of no-till practices together with the utilization of glyphosate-resistant soybean crops are factors encouraging increase in glyphosate use. This phenomenon has been more evident in Argentina and Brazil. The exclusive reliance on glyphosate as the main tool for weed management results in agroecosystems biologically more prone to glyphosate resistance evolution. PMID:18161884

Vila-Aiub, Martin M; Vidal, Ribas A; Balbi, Maria C; Gundel, Pedro E; Trucco, Frederico; Ghersa, Claudio M

2008-04-01

273

Reduced transverse relaxation rate (RR2) for improved sensitivity in monitoring myocardial iron in thalassemia.  

UK PubMed Central (United Kingdom)

PURPOSE: To evaluate the reduced transverse relaxation rate (RR2), a new relaxation index which has been shown recently to be primarily sensitive to intracellular ferritin iron, as a means of detecting short-term changes in myocardial storage iron produced by iron-chelating therapy in transfusion-dependent thalassemia patients. MATERIALS AND METHODS: A single-breathhold multi-echo fast spin-echo sequence was implemented at 3 Tesla (T) to estimate RR2 by acquiring signal decays with interecho times of 5, 9 and 13 ms. Transfusion-dependent thalassemia patients (N = 8) were examined immediately before suspending iron-chelating therapy for 1 week (Day 0), after a 1-week suspension of chelation (Day 7), and after a 1-week resumption of chelation (Day 14). RESULTS: The mean percent changes in RR2, R2, and R2* off chelation (between Day 0 and 7) were 11.9 ± 8.9%, 5.4 ± 7.7% and -4.4 ± 25.0%; and, after resuming chelation (between Day 7 and 14), -10.6 ± 13.9%, -8.9 ± 8.0% and -8.5 ± 24.3%, respectively. Significant differences in R2 and RR2 were observed between Day 0 and 7, and between Day 7 and 14, with the greatest proportional changes in RR2. No significant differences in R2* were found. CONCLUSION: These initial results demonstrate that significant differences in RR2 are detectable after a single week of changes in iron-chelating therapy, likely as a result of superior sensitivity to soluble ferritin iron, which is in close equilibrium with the chelatable cytosolic iron pool. RR2 measurement may provide a new means of monitoring the short-term effectiveness of iron-chelating agents in patients with myocardial iron overload.

Cheung JS; Au WY; Ha SY; Kim D; Jensen JH; Zhou IY; Cheung MM; Wu Y; Guo H; Khong PL; Brown TR; Brittenham GM; Wu EX

2011-06-01

274

Glyphosate catabolism by Pseudomonas sp. strain PG2982.  

UK PubMed Central (United Kingdom)

The pathway for the degradation of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. PG2982 has been determined by using metabolic radiolabeling experiments. Radiorespirometry experiments utilizing [3-14C]glyphosate revealed that approximately 50 to 59% of the C-3 carbon was oxidized to CO2. Fractionation of stationary-phase cells labeled with [3-14C]glyphosate revealed that from 45 to 47% of the assimilated label is distributed to proteins and that the amino acids methionine and serine are highly labeled. Adenine and guanine received 90% of the C-3 label found in the nucleic acid fraction, and the only pyrimidine base labeled was thymine. These results indicated that C-3 of glyphosate was at some point metabolized to a C-1 compound whose ultimate fate could be both oxidation to CO2 and distribution to amino acids and nucleic acid bases that receive a C-1 group from the C-1-donating coenzyme tetrahydrofolate. Pulse-labeling of PG2982 cells with [3-14C]glyphosate resulted in the isolation of [3-14C]sarcosine as an intermediate in glyphosate degradation. Examination of crude extracts prepared from PG2982 cells revealed the presence of a sarcosine-oxidizing enzyme that oxidizes sarcosine to glycine and formaldehyde. These results indicate that the first step in glyphosate degradation by PG2982 is cleavage of the carbon-phosphorus bond, resulting in the release of sarcosine and a phosphate group. The phosphate group is utilized as a source of phosphorus, and the sarcosine is degraded to glycine and formaldehyde. This pathway is supported by the results of [1,2-14C]glyphosate metabolism studies, which show that radioactivity in the proteins of labeled cells is found only in the glycine and serine residues.

Shinabarger DL; Braymer HD

1986-11-01

275

Glyphosate catabolism by Pseudomonas sp. strain PG2982.  

Science.gov (United States)

The pathway for the degradation of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. PG2982 has been determined by using metabolic radiolabeling experiments. Radiorespirometry experiments utilizing [3-14C]glyphosate revealed that approximately 50 to 59% of the C-3 carbon was oxidized to CO2. Fractionation of stationary-phase cells labeled with [3-14C]glyphosate revealed that from 45 to 47% of the assimilated label is distributed to proteins and that the amino acids methionine and serine are highly labeled. Adenine and guanine received 90% of the C-3 label found in the nucleic acid fraction, and the only pyrimidine base labeled was thymine. These results indicated that C-3 of glyphosate was at some point metabolized to a C-1 compound whose ultimate fate could be both oxidation to CO2 and distribution to amino acids and nucleic acid bases that receive a C-1 group from the C-1-donating coenzyme tetrahydrofolate. Pulse-labeling of PG2982 cells with [3-14C]glyphosate resulted in the isolation of [3-14C]sarcosine as an intermediate in glyphosate degradation. Examination of crude extracts prepared from PG2982 cells revealed the presence of a sarcosine-oxidizing enzyme that oxidizes sarcosine to glycine and formaldehyde. These results indicate that the first step in glyphosate degradation by PG2982 is cleavage of the carbon-phosphorus bond, resulting in the release of sarcosine and a phosphate group. The phosphate group is utilized as a source of phosphorus, and the sarcosine is degraded to glycine and formaldehyde. This pathway is supported by the results of [1,2-14C]glyphosate metabolism studies, which show that radioactivity in the proteins of labeled cells is found only in the glycine and serine residues. PMID:2430939

Shinabarger, D L; Braymer, H D

1986-11-01

276

HERBICIDAL CONCENTRATE COMPOSITIONS CONTAINING GLYPHOSATE AND DICAMBA SALTS  

UK PubMed Central (United Kingdom)

The mixture of potassium or certain amine salts of glyphosate and dicamba allows the preparation of high-strength liquid compositions containing greater than 300 gae/L of total active ingredient loading if the pH is adjusted between about 6.0 and about 8.0. Compositions are particularly well-suited for herbicidal applications on crops that are resistant or tolerant to both glyphosate and dicamba.

ZHANG HONG; TANK HOLGER; LI MEI; LIU LEI; WILSON STEPHEN L; QIN KUIDE; OUSE DAVID G

277

USE OF GLYPHOSATE SALTS IN SEED DRESSING HERBICIDAL COMPOSITIONS  

UK PubMed Central (United Kingdom)

Glyphosate salts and mixtures thereof are useful for the preparation of seed dressing, seed priming and seed coating herbicidal compositions for control of parasitic weeds such as Orobanche spp., Cuscuta spp., Striga spp. and Alectra spp., in glyphosate-resistant crop plants e.g. vegetables, legumes or cereals that contain a gene encoding a modified 5-enolpyruvyl-3-phosphoshikimate (EPSP) synthase and/or produce enhanced amounts of EPSP synthase.

GRESSEL Jonathan; JOEL Daniel M.

278

Effect of glyphosate and manganese on nutrition and yield of transgenic glyphosate-resistant soybeanEfeito de glyphosate e manganês na nutrição e produtividade da soja transgênica  

Directory of Open Access Journals (Sweden)

Full Text Available Research suggests that the application of glyphosate on transgenic glyphosate-resistant soybean can cause induced deficiency of Mn. Thus, the aim of this work was to evaluate the application of glyphosate and manganese in post-emergence on different phenological growth stages of RR soybean and its effects on leaf nutrient contents and productivity of grains. The experiment was carried out at two farms in Rio Brilhante-MS, both with randomized block experimental design with six replications at Lages de Pedra farm and four replications at São Manoel farm. Treatments were established in 3 x 8 factorial schemes, where the factor A consisted of three treatments with glyphosate (without the application of glyphosate, application of 720 g i.a. in the growth stage V2 + 480 g a. in V4, and application of 1.200 g i.a. in V4 growth stage). The factor B consisted of eight treatments with foliar application of Mn being without application, and seven Mn application was sprayed the leaves with 332 g ha-1, divided into different growth stages. The application of glyphosate on transgenic soybean did not have effect on leaf nutrient contents, including the absorbing of Mn. Yield and mass of 100 grains were not influenced by applying of glyphosate neither by leaf fertilization with Mn, and leaf applying of Mn influenced only the leaf contents of Mn and Fe.Pesquisas sugerem que a aplicação de glyphosate em soja transgênica (soja RR) pode causar deficiência induzida de Mn. Assim, objetivou-se com o trabalho avaliar a aplicação de Mn e glyphosate em pós-emergência em diferentes estádios fenológicos da soja RR e, seus efeitos nos teores foliares de nutrientes e produtividade de grãos. O experimento foi realizado em duas propriedades no município de Rio Brilhante – MS, ambos com delineamento experimental em blocos casualizados, com seis repetições na Fazenda Lages de Pedra, e quatro na Fazenda São Manoel. Os tratamentos foram dispostos em arranjo fatorial 3 x 8, onde o fator A consistiu de três tratamentos com glyphosate (sem aplicação de glyphosate, aplicação de 720 g i.a. no estádio fenológico V2 + 480 g i.a. em V4, e aplicação de 1.200 g i.a. no estádio V4). O fator B consistiu de oito tratamentos com aplicação foliar de Mn sendo uma testemunha, e sete formas de aplicação de Mn via foliar com 332 g ha-1, divididos em diferentes estádios de fenológicos. A aplicação de glyphosate na soja transgênica não apresentou efeito nos teores foliares de nutrientes, inclusive na absorção de Mn. A produtividade e a massa de 100 grãos não foram influenciadas pela aplicação de glyphosate ou pela adubação foliar com Mn, e a aplicação foliar de Mn influenciou apenas os teores foliares de Mn e Fe.

Fábio Fernando Stefanello; Marlene Estevão Marchetti; Eulene Francisco da Silva; Josemar Stefanello; Rafael Sabino Bonifácio Doreto; José Oscar Novelino

2011-01-01

279

PHYTO-MICROBIAL DEGRADATION OF GLYPHOSATE IN RIYADH AREA  

Directory of Open Access Journals (Sweden)

Full Text Available Greenhouse studies were conducted to determine the ability of plant Amaranth, Amaranthus caudate and two isolated bacterial strains from rhizosphere region for cleaning up glyphosate residues in soil and plants. The analytical study of the biodegradation of glyphosate was carried out in the laboratory conditions. Amaranth, Amaranthus caudate and two isolated bacterial strains namely Pseudomonas aeruginosa and Bacillus megaterium could degrade glyphosate in 5 days. These results suggested that phytoremediation could accelerate the degradation of glyphosate residues in plants and in rhizosphere region as well. Glyphosate had strong effect on bacterial DNA where many DNA bands were affected. This could be explained that the effect of herbicide glyphosate on the protein profile may reflex somehow DNA mutation occurred during the assimilation of those toxic compounds. Therefore, the alteration occurred in both DNA and protein profiles is considered a degree of tolerance that lead to DNA mutation to cope with the assimilation of this compound. Therefore, the phytoremediation way could be a promising tool in program is to protect public health and the environment by ensuring the safety and availability of herbicides and pesticide alternatives.

ABDEL-MEGEED A.; SADIK M.W.; AL-SHAHRANI H.O.; ALI H.M.

2013-01-01

280

Pool of resistance mechanisms to glyphosate in Digitaria insularis.  

Science.gov (United States)

Digitaria insularis biotypes resistant to glyphosate have been detected in Brazil. Studies were carried out in controlled conditions to determine the role of absorption, translocation, metabolism, and gene mutation as mechanisms of glyphosate resistance in D. insularis. The susceptible biotype absorbed at least 12% more (14)C-glyphosate up to 48 h after treatment (HAT) than resistant biotypes. High differential (14)C-glyphosate translocation was observed at 12 HAT, so that >70% of the absorbed herbicide remained in the treated leaf in resistant biotypes, whereas 42% remained in the susceptible biotype at 96 HAT. Glyphosate was degraded to aminomethylphosphonic acid (AMPA), glyoxylate, and sarcosine by >90% in resistant biotypes, whereas a small amount of herbicide (up to 11%) was degraded by the susceptible biotype up to 168 HAT. Two amino acid changes were found at positions 182 and 310 in EPSPS, consisting of a proline to threonine and a tyrosine to cysteine substitution, respectively, in resistant biotypes. Therefore, absorption, translocation, metabolism, and gene mutation play an important role in the D. insularis glyphosate resistance. PMID:22175446

de Carvalho, Leonardo Bianco; Alves, Pedro Luis da Costa Aguiar; González-Torralva, Fidel; Cruz-Hipolito, Hugo Enrique; Rojano-Delgado, Antonia María; De Prado, Rafael; Gil-Humanes, Javier; Barro, Francisco; de Castro, María Dolores Luque

2012-01-05

 
 
 
 
281

Pool of resistance mechanisms to glyphosate in Digitaria insularis.  

UK PubMed Central (United Kingdom)

Digitaria insularis biotypes resistant to glyphosate have been detected in Brazil. Studies were carried out in controlled conditions to determine the role of absorption, translocation, metabolism, and gene mutation as mechanisms of glyphosate resistance in D. insularis. The susceptible biotype absorbed at least 12% more (14)C-glyphosate up to 48 h after treatment (HAT) than resistant biotypes. High differential (14)C-glyphosate translocation was observed at 12 HAT, so that >70% of the absorbed herbicide remained in the treated leaf in resistant biotypes, whereas 42% remained in the susceptible biotype at 96 HAT. Glyphosate was degraded to aminomethylphosphonic acid (AMPA), glyoxylate, and sarcosine by >90% in resistant biotypes, whereas a small amount of herbicide (up to 11%) was degraded by the susceptible biotype up to 168 HAT. Two amino acid changes were found at positions 182 and 310 in EPSPS, consisting of a proline to threonine and a tyrosine to cysteine substitution, respectively, in resistant biotypes. Therefore, absorption, translocation, metabolism, and gene mutation play an important role in the D. insularis glyphosate resistance.

de Carvalho LB; Alves PL; González-Torralva F; Cruz-Hipolito HE; Rojano-Delgado AM; De Prado R; Gil-Humanes J; Barro F; de Castro MD

2012-01-01

282

Studies on a new group of biodegradable surfactants for glyphosate.  

Science.gov (United States)

The effectiveness of a homologous series of biodegradable rapeseed oil derivatives (triglyceride ethoxylates; Agnique RSO series containing an average of 5, 10, 30 and 60 units of ethylene oxide (EO) as adjuvants for foliage-applied, water-soluble, systemic active ingredients was evaluated employing glyphosate as an example. Previous experiments had revealed that the surfactants used are not phytotoxic at concentrations ranging from 1 to 10 g litre-1. The experiments were performed using Phaseolus vulgaris L and nine selected weed species, grown in a growth chamber at 25/20 (+/- 2) degrees C day/night temperature and 40/70 (+/- 10)% relative humidity. The surfactants were evaluated for enhancement of spray retention, and foliar penetration biological efficacy of glyphosate. Glyphosate was applied at a concentration of 43 mM. The surfactants were added at concentrations of 1 g litre-1. The commercial glyphosate 360 g AE litre-1 SL Roundup Ultra and unformulated glyphosate served as references. The surfactants used improved spray retention, foliar penetration and biological efficacy. Some of the formulations were comparable to the performance of Roundup Ultra in the aspects evaluated; some were even more effective in enhancing spray liquid retention and promoting glyphosate phytotoxicity in several plant species. In these studies Agnique RSO 60 generally was most effective. PMID:12192908

Haefs, Roland; Schmitz-Eiberger, Michaela; Mainx, Hans-G; Mittelstaedt, Werner; Noga, Georg

2002-08-01

283

Studies on a new group of biodegradable surfactants for glyphosate.  

UK PubMed Central (United Kingdom)

The effectiveness of a homologous series of biodegradable rapeseed oil derivatives (triglyceride ethoxylates; Agnique RSO series containing an average of 5, 10, 30 and 60 units of ethylene oxide (EO) as adjuvants for foliage-applied, water-soluble, systemic active ingredients was evaluated employing glyphosate as an example. Previous experiments had revealed that the surfactants used are not phytotoxic at concentrations ranging from 1 to 10 g litre-1. The experiments were performed using Phaseolus vulgaris L and nine selected weed species, grown in a growth chamber at 25/20 (+/- 2) degrees C day/night temperature and 40/70 (+/- 10)% relative humidity. The surfactants were evaluated for enhancement of spray retention, and foliar penetration biological efficacy of glyphosate. Glyphosate was applied at a concentration of 43 mM. The surfactants were added at concentrations of 1 g litre-1. The commercial glyphosate 360 g AE litre-1 SL Roundup Ultra and unformulated glyphosate served as references. The surfactants used improved spray retention, foliar penetration and biological efficacy. Some of the formulations were comparable to the performance of Roundup Ultra in the aspects evaluated; some were even more effective in enhancing spray liquid retention and promoting glyphosate phytotoxicity in several plant species. In these studies Agnique RSO 60 generally was most effective.

Haefs R; Schmitz-Eiberger M; Mainx HG; Mittelstaedt W; Noga G

2002-08-01

284

A glyphosate-based pesticide impinges on transcription  

International Nuclear Information System (INIS)

Widely spread chemicals used for human benefits may exert adverse effects on health or the environment, the identification of which are a major challenge. The early development of the sea urchin constitutes an appropriate model for the identification of undesirable cellular and molecular targets of pollutants. The widespread glyphosate-based pesticide affected sea urchin development by impeding the hatching process at millimolar range concentration of glyphosate. Glyphosate, the active herbicide ingredient of Roundup, by itself delayed hatching as judged from the comparable effect of different commercial glyphosate-based pesticides and from the effect of pure glyphosate addition to a threshold concentration of Roundup. The surfactant polyoxyethylene amine (POEA), the major component of commercial Roundup, was found to be highly toxic to the embryos when tested alone and therefore could contribute to the inhibition of hatching. Hatching, a landmark of early development, is a transcription-dependent process. Correlatively, the herbicide inhibited the global transcription, which follows fertilization at the 16-cell stage. Transcription inhibition was dose-dependent in the millimolar glyphosate range concentration. A 1257-bp fragment of the hatching enzyme transcript from Sphaerechinus granularis was cloned and sequenced; its transcription was delayed by 2 h in the pesticide-treated embryos. Because transcription is a fundamental basic biological process, the pesticide may be of health concern by inhalation near herbicide spraying at a concentration 25 times the adverse transcription concentration in the sprayed microdroplets

2005-02-15

285

Effects of glyphosate-based herbicides on embryo-larval development and metamorphosis in the Pacific oyster, Crassostrea gigas.  

Science.gov (United States)

Pesticides may be involved in oyster summer mortality events, not necessarily as a single causative agent but as an additional stressor. In this context, the present study aimed to assess the toxicity of glyphosate, its by-product, aminomethylphosphonic acid (AMPA) and two commercial formulations, Roundup Express(®) (R(EX)) and Roundup Allées et Terrasses(®) (R(AT)), containing glyphosate as the active ingredient, on the early life stages of the Pacific oyster, Crassostrea gigas. The embryotoxicity of these chemicals were quantified by considering both the rates of abnormalities and the arrested development or types of abnormalities in D-shaped larvae after 48 h exposure. The success of metamorphosis was examined in pediveliger larvae exposed for 24 h. Experiments involving both endpoints included range finding experiments for herbicide concentrations ranging from 0.1 to 100,000 ?g L(-1). This range was then narrowed down in order to determine precise EC(50) values. Actual concentrations of the herbicide were determined at the beginning and after 48 h (embryotoxicity) and 24 h (metamorphosis) to evaluate the potential temporal variation in the concentrations. During embryo-larval development, no mortalities were recorded at any of the concentrations of glyphosate and AMPA, whereas no embryos or D-shaped larvae could be observed after exposure to 10,000 ?g L(-1) of R(EX) or R(AT). Compared with the controls, no effects on embryo-larval development were recorded between 0.1 and 1000 ?g L(-1), regardless of the chemical tested. Above a threshold, which varied according to the chemical used, the gradient of herbicide concentrations correlated with a gradient of severity of abnormality ranging from normal larvae to arrested development (an "old embryo" stage). The EC(50) values were 28,315 and 40,617 ?g L(-1) for glyphosate and its metabolite, respectively, but much lowered values of 1133 and 1675 ?g L(-1) for R(EX) and R(AT), respectively. Metamorphosis tests also revealed a significant difference between molecules, as the EC(50) values exceeded 100,000 ?g L(-1) for glyphosate and AMPA but were as low as 6366 and 6060 ?g L(-1) for the commercial formulations, which appeared relatively more toxic. Overall, the embryo-larval development of C. gigas was more sensitive to glyphosate-based herbicides compared to various endpoints studied in regulatory model organisms, and embryos and D-shaped larvae were more sensitive compared to pediveliger larvae. PMID:23277103

Mottier, Antoine; Kientz-Bouchart, Valérie; Serpentini, Antoine; Lebel, Jean Marc; Jha, Awadhesh N; Costil, Katherine

2012-12-10

286

Effects of glyphosate-based herbicides on embryo-larval development and metamorphosis in the Pacific oyster, Crassostrea gigas.  

UK PubMed Central (United Kingdom)

Pesticides may be involved in oyster summer mortality events, not necessarily as a single causative agent but as an additional stressor. In this context, the present study aimed to assess the toxicity of glyphosate, its by-product, aminomethylphosphonic acid (AMPA) and two commercial formulations, Roundup Express(®) (R(EX)) and Roundup Allées et Terrasses(®) (R(AT)), containing glyphosate as the active ingredient, on the early life stages of the Pacific oyster, Crassostrea gigas. The embryotoxicity of these chemicals were quantified by considering both the rates of abnormalities and the arrested development or types of abnormalities in D-shaped larvae after 48 h exposure. The success of metamorphosis was examined in pediveliger larvae exposed for 24 h. Experiments involving both endpoints included range finding experiments for herbicide concentrations ranging from 0.1 to 100,000 ?g L(-1). This range was then narrowed down in order to determine precise EC(50) values. Actual concentrations of the herbicide were determined at the beginning and after 48 h (embryotoxicity) and 24 h (metamorphosis) to evaluate the potential temporal variation in the concentrations. During embryo-larval development, no mortalities were recorded at any of the concentrations of glyphosate and AMPA, whereas no embryos or D-shaped larvae could be observed after exposure to 10,000 ?g L(-1) of R(EX) or R(AT). Compared with the controls, no effects on embryo-larval development were recorded between 0.1 and 1000 ?g L(-1), regardless of the chemical tested. Above a threshold, which varied according to the chemical used, the gradient of herbicide concentrations correlated with a gradient of severity of abnormality ranging from normal larvae to arrested development (an "old embryo" stage). The EC(50) values were 28,315 and 40,617 ?g L(-1) for glyphosate and its metabolite, respectively, but much lowered values of 1133 and 1675 ?g L(-1) for R(EX) and R(AT), respectively. Metamorphosis tests also revealed a significant difference between molecules, as the EC(50) values exceeded 100,000 ?g L(-1) for glyphosate and AMPA but were as low as 6366 and 6060 ?g L(-1) for the commercial formulations, which appeared relatively more toxic. Overall, the embryo-larval development of C. gigas was more sensitive to glyphosate-based herbicides compared to various endpoints studied in regulatory model organisms, and embryos and D-shaped larvae were more sensitive compared to pediveliger larvae.

Mottier A; Kientz-Bouchart V; Serpentini A; Lebel JM; Jha AN; Costil K

2013-03-01

287

Comparative losses of glyphosate and selected residual herbicides in surface runoff from conservation-tilled watersheds planted with corn or soybean.  

UK PubMed Central (United Kingdom)

Residual herbicides regularly used in conjunction with conservation tillage to produce corn ( L.) and soybean [ (L.) Merr] are often detected in surface water at concentrations that exceed their U.S. maximum contaminant levels (MCL) and ecological standards. These risks might be reduced by planting glyphosate-tolerant varieties of these crops and totally or partially replacing the residual herbicides alachlor, atrazine, linuron, and metribuzin with glyphosate, a contact herbicide that has a short half-life and is strongly sorbed to soil. Therefore, we applied both herbicide types at typical rates and times to two chisel-plowed and two no-till watersheds in a 2-yr corn/soybean rotation and at half rates to three disked watersheds in a 3-yr corn/soybean/wheat-red clover ( L.- L.) rotation and monitored herbicide losses in surface runoff for three crop years. Average dissolved glyphosate loss for all tillage practices, as a percentage of the amount applied, was significantly less ( ? 0.05) than the losses of atrazine (21.4x), alachlor (3.5x), and linuron (8.7x) in corn-crop years. Annual, flow-weighted, concentration of atrazine was as high as 41.3 ?g L, much greater than its 3 ?g L MCL. Likewise, annual, flow-weighted alachlor concentration (MCL = 2 ?g L) was as high as 11.2 and 4.9 ?g L in corn- and soybean-crop years, respectively. In only one runoff event during the 18 watershed-years it was applied did glyphosate concentration exceed its 700 ?g L MCL and the highest, annual, flow-weighted concentration was 3.9 ?g L. Planting glyphosate-tolerant corn and soybean and using glyphosate in lieu of some residual herbicides should reduce the impact of the production of these crops on surface water quality.

Shipitalo MJ; Owens LB

2011-07-01

288

An intercomparison study on the determinations of glyphosate, chlormequat and mepiquat residues in wheat  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract An intercomparison study on the analytical determinations of glyphosate, chlormequat and mepiquat residues in cereals was performed. Four samples were sent to six participating laboratories, one blank, two incurred and one spiked sample. For glyphosate, two laboratories reported con...

289

Method for preparing glyphosate by PMIDA of catalytic oxidizing by gas containing molecular oxygen  

UK PubMed Central (United Kingdom)

This invention relates to a method of using gas containing molecular oxygen to catalytic oxidate double-gan phosphine for preparing glyphosate. The steps:(1) mix double-gan phosphine, water and activated carbon, at condition of speed of agitator 800 to 1500 r/m , inlet oxygen enrichment gas to carry out reaction, reactant liquor for refrigeration, glyphosate seed out, collect glyphosate and activated carbon blending press cake, divide mother solution with deleterious impurities such as formaldehyde (2) plunge glyphosate and activated carbon admixture press cake to glyphosate saturation solution, after glyphosate dissolving take filtration while hot, filtrate recooling, glyphosate seedout, cake drying, then gain glyphosate solid or plunge press cake to water, cooling, drop isopropylamine or inlet alkaline air, directly prepare isopropylamine salt or ammonium salt water solution.

LI XINRONG

290

Central fuel banking to reduce the number of proliferation sensitive enrichment activities  

International Nuclear Information System (INIS)

Central fuel banking is a complex international political, economic and technical concept that aims to reduce uncontrolled spreading of uranium enrichment technology in the world in order to prevent proliferation of nuclear weapons. This paper first gives an outline of the notions: 'non-proliferation', the 'front-end' of the fuel cycle, the scope of fuel baking, nuclear fuel and the 60 years of enrichment technology. Enrichment technology is highly concentrated in the nuclear weapon states and other developed countries, but this is not exclusive any more. The technology is spreading. The global demand for enrichment services - parallel to massive nuclear investments in the civil sector and the ageing of older facilities - is constantly growing. Proliferation sensitivity calls for an effective and comprehensive non-proliferation regime. The solution may be multilateralizing the nuclear fuel cycle. After a historical overview, the proposals on multilateral nuclear approaches are presented. The assessment of the proposals is complex in the dimensions of: the non-proliferation aim, the assurance of supply aspect and other variables such as legal issues and non-nuclear inducements. A general evaluation and the recommendations of the Expert Panel of the IAEA are introduced outlining a plan on a middle- and long-term basis. The conclusion of the paper stresses the importance and challenge in finding the 'new balance' between obligations and interests of the members of the global community stating that the answers will have a significant impact on the nuclear indus- try, world wide economics and security policy. (orig.)

2008-01-01

291

Moderately reduced graphene oxide as transparent counter electrodes for dye-sensitized solar cells  

International Nuclear Information System (INIS)

Moderately reduced graphene oxide (GO) films were fabricated by simple and fast thermal treatment of solution processed GO, and their application as an alternative to conventional Pt counter electrode in dye-sensitized solar cells (DSSCs) was investigated. GO without thermal treatment and thermally treated GO at 150 °C showed low efficiency of ?0.5%, whereas cell performance was significantly improved by applying thermal treatment over 250 °C. In particular, the DSSC with GO thermally treated at 350 °C exhibited the highest performance with open-circuit voltage (VOC) of 0.66 V, short-circuit current density (JSC) of 16.35 mA/cm2, F.F. of 33.33%, and overall power conversion efficiency (PCE) of 3.60%. Moderate reduction of GO by simple thermal treatment over 250 °C was confirmed through the measurements of X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). Enhancement of efficiency after high temperature thermal treatment might be attributed to the improved electrical conductivities and higher catalytic activities, resulting from the reduction of GO.

2012-10-30

292

Highly sensitive reduced graphene oxide impedance sensor harnessing ?-stacking interaction mediated direct deposition of protein probes.  

UK PubMed Central (United Kingdom)

Graphene-based electrochemical impedance sensors have recently received much attention due to their outstanding sensing capability and economic viability. In this study, we present a novel means of constructing an impedance sensing platform via harnessing intrinsic ?-stacking interactions between probe protein molecules and reduced graphene oxide (RGO) substrate, obviating the need for introducing external chemical groups often required for covalent anchoring of the probes. To achieve this goal, protein molecules used as a probe were denatured to render their hydrophobic residues exposed in order to facilitate their direct ?-stacking interactions with the surface of RGO nanosheets. The protein molecules in denatured form, which would otherwise have difficulty in undergoing ?-stacking interactions with the RGO surface, were found to uniformly cover the RGO nanosheets at high density, conducive to providing a graphene-based impedance sensing platform capable of detecting a probe-specific analyte at high sensitivity. The proof-of-concept performance of thus-constructed RGO-based impedance sensors was demonstrated via selective detection of biological binding events of antigen-antibody reaction at a femtomolar range. Notably, since the ?-stacking interaction can occur on the entire RGO surface, it can desirably exclude a backfill process indispensable for the conventional biosensors to suppress background noise signals. Since the procedure of ?-stacking mediated direct deposition of on-purpose denatured protein probes onto the RGO surface is facile and straightforward, the proposed strategy is anticipated to extend its applicability for fabrication of high performance graphene-based bio or chemical sensors.

Kim KS; Um YM; Jang JR; Choe WS; Yoo PJ

2013-05-01

293

Speciation of glyphosate, phosphate and aminomethylphosphonic acid in soil extracts by ion chromatography with inductively coupled plasma mass spectrometry with an octopole reaction system.  

UK PubMed Central (United Kingdom)

Ion-pairing chromatography coupled with inductively coupled plasma mass spectrometry (ICP-MS) used for the speciation of phosphorus is limited as the mobile phase containing organic solvents changes in detection sensitivity and the carbon precipitates on torch and cones. To address this issue, anion-exchange chromatography with ICP-MS has been used for the speciation of glyphosate, phosphate and aminomethylphosphonic acid in soil extracts. The separation of the targets on a new column was achieved within 5 min using an eluent containing 20 mM NH(4)NO(3) at pH 5.1. Furthermore, since the polyatomic ions such as (14)N(16)O(1)H(+) and (15)N(16)O(+) from a nitrogen-based ion-pairing reagent interfered with ICP-MS detection of (31)P, an octopole reaction system was investigated to determine whether the polyatomic interferences could be reduced. The results show that addition of He to the cell can benefit analyses by reducing such interferences, but at the expense of reduced sensitivity. The detection limits in the range of 1.0-1.5 microg L(-1) (expressed as P) was achieved when 50 microL was injected using He as the collusion gas.

Chen Z; He W; Beer M; Megharaj M; Naidu R

2009-05-01

294

Speciation of glyphosate, phosphate and aminomethylphosphonic acid in soil extracts by ion chromatography with inductively coupled plasma mass spectrometry with an octopole reaction system.  

Science.gov (United States)

Ion-pairing chromatography coupled with inductively coupled plasma mass spectrometry (ICP-MS) used for the speciation of phosphorus is limited as the mobile phase containing organic solvents changes in detection sensitivity and the carbon precipitates on torch and cones. To address this issue, anion-exchange chromatography with ICP-MS has been used for the speciation of glyphosate, phosphate and aminomethylphosphonic acid in soil extracts. The separation of the targets on a new column was achieved within 5 min using an eluent containing 20 mM NH(4)NO(3) at pH 5.1. Furthermore, since the polyatomic ions such as (14)N(16)O(1)H(+) and (15)N(16)O(+) from a nitrogen-based ion-pairing reagent interfered with ICP-MS detection of (31)P, an octopole reaction system was investigated to determine whether the polyatomic interferences could be reduced. The results show that addition of He to the cell can benefit analyses by reducing such interferences, but at the expense of reduced sensitivity. The detection limits in the range of 1.0-1.5 microg L(-1) (expressed as P) was achieved when 50 microL was injected using He as the collusion gas. PMID:19269440

Chen, Zuliang; He, Wenxiang; Beer, Michael; Megharaj, Mallavarapu; Naidu, Ravendra

2009-01-15

295

Comparative environmental impacts of glyphosate and conventional herbicides when used with glyphosate-tolerant and non-tolerant crops  

International Nuclear Information System (INIS)

The introduction of glyphosate-tolerant (GT) crops is expected to mitigate the environmental contamination by herbicides because glyphosate is less persistent and toxic than the herbicides used on non-GT crops. Here, we compared the environmental balances of herbicide applications for both crop types in three French field trials. The dynamic of herbicides and their metabolites in soil, groundwater and air was simulated with PRZM model and compared to field measurements. The associated impacts were aggregated with toxicity potentials calculated with the fate and exposure model USES for several environmental endpoints. The impacts of GT systems were lower than those of non-GT systems, but the accumulation in soils of one glyphosate metabolite (aminomethylphosphonic acid) questions the sustainability of GT systems. The magnitude of the impacts depends on the rates and frequency of glyphosate application being highest for GT maize monoculture and lowest for combination of GT oilseed rape and non-GT sugarbeet crops. - The impacts of herbicide applications on glyphosate-tolerant crops could be higher than expected due to the accumulation of a metabolite of glyphosate in soils.

296

Comparative environmental impacts of glyphosate and conventional herbicides when used with glyphosate-tolerant and non-tolerant crops  

Energy Technology Data Exchange (ETDEWEB)

The introduction of glyphosate-tolerant (GT) crops is expected to mitigate the environmental contamination by herbicides because glyphosate is less persistent and toxic than the herbicides used on non-GT crops. Here, we compared the environmental balances of herbicide applications for both crop types in three French field trials. The dynamic of herbicides and their metabolites in soil, groundwater and air was simulated with PRZM model and compared to field measurements. The associated impacts were aggregated with toxicity potentials calculated with the fate and exposure model USES for several environmental endpoints. The impacts of GT systems were lower than those of non-GT systems, but the accumulation in soils of one glyphosate metabolite (aminomethylphosphonic acid) questions the sustainability of GT systems. The magnitude of the impacts depends on the rates and frequency of glyphosate application being highest for GT maize monoculture and lowest for combination of GT oilseed rape and non-GT sugarbeet crops. - The impacts of herbicide applications on glyphosate-tolerant crops could be higher than expected due to the accumulation of a metabolite of glyphosate in soils.

Mamy, Laure, E-mail: laure.mamy@versailles.inra.f [INRA-AgroParisTech, UMR 1091 Environnement et Grandes Cultures, 78850 Thiverval-Grignon (France); Gabrielle, Benoit, E-mail: benoit.gabrielle@agroparistech.f [INRA-AgroParisTech, UMR 1091 Environnement et Grandes Cultures, 78850 Thiverval-Grignon (France); Barriuso, Enrique, E-mail: barriuso@grignon.inra.f [INRA-AgroParisTech, UMR 1091 Environnement et Grandes Cultures, 78850 Thiverval-Grignon (France)

2010-10-15

297

Differential Effects of Glyphosate and Roundup on Human Placental Cells and Aromatase  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Roundup is a glyphosate-based herbicide used worldwide, including on most genetically modified plants that have been designed to tolerate it. Its residues may thus enter the food chain, and glyphosate is found as a contaminant in rivers. Some agricultural workers using glyphosate have pregnancy prob...

Richard, Sophie; Moslemi, Safa; Sipahutar, Herbert; Benachour, Nora; Seralini, Gilles-Eric

298

Reduced baroreflex sensitivity in alcoholic cirrhosis: relations to hemodynamics and humoral systems.  

DEFF Research Database (Denmark)

In cirrhosis, arterial vasodilatation leads to central hypovolemia and activation of the sympathetic nervous and renin-angiotensin-aldosterone systems. As the liver disease and circulatory dysfunction may affect baroreflex sensitivity (BRS), we assessed BRS in a large group of patients with cirrhosis and in controls who were all supine and some after 60 degrees passive head-up and 30 degrees head-down tilting in relation to central hemodynamics and activity of the sympathetic nervous and renin-angiotensin-aldosterone systems. One-hundred and five patients (Child classes A/B/C: 21/55/29) and 25 (n=11 + 14) controls underwent a full hemodynamic investigation. BRS was assessed by cross-spectral analysis of variabilities between blood pressure and heart rate time series. The median BRS was significantly lower in the supine cirrhotic patients, 3.7 (range 0.3-30.7) ms/mmHg than in matched controls (n=11): 14.3 (6.1-23.6) ms/mmHg, P<0.001. A stepwise multiple-regression analysis revealed that serum sodium (P=0.044), heart rate (P=0.027), and central circulation time (P=0.034) independently correlated with BRS. Head-down tilting had no effects on BRS, but, after head-up tilting, BRS was similar in the patients (n=23) and controls (n=14). In conclusion, BRS is reduced in cirrhosis in the supine position and relates to various aspects of cardiovascular dysfunction, but no further reduction was observed in parallel with the amelioration of the hyperdynamic circulation after head-up tilting. The results indicate that liver dysfunction and compensatory mechanisms to vasodilatation may be involved in the low BRS, which may contribute to poor cardiovascular adaptation in cirrhosis.

MØller, SØren; Iversen, Jens S

2007-01-01

299

Manejo de capim pé-de-galinha em lavouras de soja transgênica resistente ao glifosato Management of goose grass on transgenic soybean, resistant to glyphosate  

Directory of Open Access Journals (Sweden)

Full Text Available O objetivo deste trabalho foi avaliar a resistência de capim pé-de-galinha (Eleusine indica) ao glifosato, em lavouras de soja transgênica; avaliar o efeito de aplicações de glifosato em diferentes estádios de desenvolvimento; identificar práticas agronômicas associadas à seleção de biótipos resistentes; e avaliar a eficiência dos herbicidas cletodim, fluazifope-P-butílico, clomazona, glufosinato de amônio e glifosato nas plantas resistentes. Plantas escapes ao tratamento com glifosato foram coletadas em 24 propriedades, no Rio Grande do Sul. As plantas foram cultivadas em casa de vegetação, tendo-se avaliado a sua resistência ao glifosato. Os acessos resistentes foram selecionados e avaliados quanto ao efeito da aplicação do glifosato em diferentes estádios de crescimento e quanto à sensibilidade aos herbicidas. Foi aplicado um questionário aos produtores para identificação das práticas agronômicas associadas às falhas no controle. O controle de E. indica pelo glifosato é mais efetivo com a aplicação em estádios iniciais de desenvolvimento. Práticas agronômicas, como uso contínuo de baixas doses do herbicida, aplicação em estádios de desenvolvimento avançados das plantas daninhas (mais de um afilho) e a ausência de rotação de culturas foram relacionadas às falhas de controle observadas. Os herbicidas cletodim, fluazifope-P-butílico e glufosinato de amônio são alternativas eficientes para o controle de E. indica.The objective of this work was to evaluate the resistance of goose grass (Eleusine indica) to glyphosate application in transgenic soybean crops; evaluate the effect of glyphosate applications in different growth stages; identify the main agronomic practices associated with the selection of resistant biotypes; and evaluate the effect of the herbicides clethodim, fluazifop-p-butyl, clomazone, glufosinate ammonium, and glyphosate on resistant plants. Plants that survived glyphosate application were collected on 24 properties in the state of Rio Grande do Sul, Brazil. Plants were grown in greenhouse and their resistance to glyphosate was evaluated. The resistant accessions were selected and evaluated as to the effect of glyphosate application on different growth stages and to their sensitivity to the herbicides. A questionnaire was given to producers in order to identify agronomic practices associated with control failures. The control of E. indica by glyphosate is more effective at initial growth stages. Agronomic practices, such as continued use of low doses of glyphosate, application on advanced weed growth stages (more than one tiller), and absence of crop rotation were related to the observed control failures. The herbicides clethodim, fluazifop-p-butyl, and glufosinate ammonium are efficient alternatives to control E. indica.

André da Rosa Ulguim; Leandro Vargas; Dirceu Agostinetto; Taísa Dal Magro; Nixon da Rosa Westendorff; Marcelo Timm Holz

2013-01-01

300

Control of winter cereals in the spring with glyphosate  

UK PubMed Central (United Kingdom)

Poor survival of winter cereals due to winter conditions in Ontario can necessitate destruction of the stand in the spring to allow the subsequent seeding of an alternative crop. Winter cereals were seeded in the autumn of 2004 and 2005 at the Huron Research Station and at the University of Guelph Ridgetown Campus in Ontario to evaluate two formulations of glyphosate [potassium (K) vs diammonium (DA) salt] at different doses (225, 450, 675, 900, or 1350g a.e. ha?¹) for the burn-off of soft white winter wheat (SWW), soft red winter wheat (SRW), hard red winter wheat (HRW) and autumn rye (AR) in either late April or early May. There was no difference between the glyphosate formulations for the control of winter cereals at 1, 2, 3, and 4weeks after treatment (WAT). There was generally improved control with glyphosate applications made in early May compared to late April however results were not always statistically significant. Generally, control of winter cereals increased as the glyphosate dose was increased from 225 to 1350g a.e. ha?¹. The minimum dose of glyphosate required for providing 90% or greater control of SWW, SRW, HRW, and AR was 675g a.e. ha?¹ at 4 WAT. Glyphosate applied at 675g a.e. ha?¹ caused a 98, 97, 98, and 99% reduction in shoot dry weight of SWW, SRW, HRW, and AR, respectively. Based on this study glyphosate (K or DA) applied in late April or early May can be used at doses as low as 675g a.e. ha?¹ to adequately control SWW, SRW, HRW, and AR in the spring.

Soltani Nader; Shropshire Christy; Sikkema PeterH

2010-05-01

 
 
 
 
301

Deposição de glyphosate aplicado para controle de plantas daninhas em soja transgênica Glyphosate deposition for weed control in transgenic soybean  

Directory of Open Access Journals (Sweden)

Full Text Available Inúmeros fatores estão envolvidos na tecnologia de aplicação de um herbicida, sendo a deposição correta fundamental para que o produto possa expressar sua eficiência. Com o objetivo de avaliar a deposição de uma solução traçante constituída de glyphosate Roundup Ready (0,96 kg e.a. ha-1) + corante FDC-1 (1.500 ppm), foi conduzido um experimento em área semeada com soja transgênica e infestada com amendoim-bravo (Euphorbia heterophylla), localizada em Londrina-PR. As aplicações foram efetuadas em diferentes estádios de desenvolvimento da cultura, correspondendo a 17, 24, 31, 38 e 45 dias após a emergência da soja. Os alvos, plantas de soja, amendoim-bravo e placas na superfície do solo (linha e entrelinha), foram coletados após pulverização, e a solução traçante foi nestes depositada, posteriormente recuperada através de lavagem com agitação em água destilada. As amostras das soluções recuperadas foram submetidas à análise, utilizando-se procedimentos espectrofotométricos, e os resultados de absorbância convertidos para concentração em µL cm-2 e µL por planta. As freqüências acumuladas dos dados originais de depósito foram adequadamente ajustadas segundo modelo de Gompertz, apresentando elevada precisão (R² > 0,95). Os resultados indicaram que o depósito da calda de pulverização nas plantas de soja e amendoim-bravo reduziu progressivamente com o desenvolvimento da cultura e infestação, sugerindo que a maior garantia de eficiência de controle pode ser conseguida com aplicações precoces.Several factors are involved in herbicide application technology, with correct deposition being essential to ensure product efficacy. To evaluate the deposition of a glyphosate tracer solution (RR) with an FDC-1 dye, an experiment was carried out in a transgenic soybean cultivated area, infested with wild poinsettia (Euphorbia heterophylla). Applications were carried out at different crop development stages, corresponding to 17; 24; 31; 38 and 45 days after soybean emergence. The targets, soybean plants, wild poinsettias, and Petri dishes on the soil surface, were collected after spraying and the tracer solution was later recovered by washing and stirring in distilled water. Samples of recovered solutions were submitted to spectrophotometer analysis, and the absorption data were converted in µL cm-2 and µL per plant. The accumulated frequencies of the original deposit data were adequately adjusted to the Gompertz model, showing high precision (R² > 0.95). The results showed that the spraying solution deposition on soybean plants and wild poinsettia reduced progressively with crop development and weed infestation, suggesting that control efficiency can be obtained with early applications.

D.L.P. Gazziero; C.D.G. Maciel; R.T. Souza; E.D. Velini; C.E.C. Prete; W. Oliveira Neto

2006-01-01

302

Weed Control, Environmental Impact and Profitability of Weed Management Strategies in Glyphosate-Resistant Corn  

Directory of Open Access Journals (Sweden)

Full Text Available Eleven field trials were conducted over a three-year period (2006-2008) at three locations in southwestern Ontario, Canada to evaluate the effect of various weed management strategies in glyphosate-tolerant corn on weed control, crop injury, corn yield, environmental impact and profit margin. No visible injury resulted from the herbicide treatments evaluated. Overall, the effect of all factors assessed were location specific. By 56 days after treatment, depending on location, glyphosate applied at the 7 - 8 leaf stage (LPOST), preemergence (PRE) herbicides followed by (fb) glyphosate LPOST and sequential glyphosate applications (EPOST (3 - 4 leaf stage) followed by LPOST) provided more consistent control of annual broadleaf weeds and annual grasses compared to glyphosate applied alone EPOST. Weed control at 56 days after treatment was lower when glyphosate was applied alone LPOST compared to sequential applications of glyphosate or PRE herbicides fb glyphosate. There were no differences in corn yield among the sequential programs evaluated; however, a yield benefit was found when a sequential program was used compared to glyphosate applied alone LPOST. Among the sequential programs the lowest environmental impact was isoxaflutole/atrazine fb glyphosate. The lowest profit margins were associated with atrazine, S-metolachlor/atrazine/benoxacor, dicamba/atrazine and glyphosate LPOST treatments compared to all other treatments. Overall, profit margins tended to be somewhat higher for treatments that included glyphosate applications. Based on these results, the most efficacious and profitable weed management program in corn was a sequential application of glyphosate; however, isoxaflutole/atrazine fb glyphosate was the treatment with the lowest environmental risk while also adding glyphosate stewardship benefits.

Nader Soltani; Christie L. Stewart; Robert E. Nurse; Laura L. Van Eerd; Richard J. Vyn; Peter H. Sikkema

2012-01-01

303

Low-Sodium DASH reduces oxidative stress and improves vascular function in salt-sensitive humans.  

UK PubMed Central (United Kingdom)

Salt induces oxidative stress in salt-sensitive (SS) animals and man. It is not known whether in SS subjects the low-sodium dietary approaches to stop hypertension (LS-DASH) reduces oxidative stress more than DASH, which is high in antioxidants. To assess the effects of DASH and LS-DASH on oxidative stress, 19 volunteers were studied after 3 weeks of a standardized usual low fruits and vegetables diet (ULFV), followed by 3 weeks on DASH (both diets approximately 120 mmol Na(+) per day), then 3 weeks on LS-DASH (60 mmol Na(+) per day). SS was defined as systolic blood pressure >or=5 mm Hg lower on LS-DASH than DASH. In SS subjects (N=9), systolic blood pressure was lower on LS-DASH (111.0+/-2.0 mm Hg) than DASH (118.0+/-2.2, P<0.01) and ULFV (122.3+/-2.7, P=0.002). In salt-resistant (SR) volunteers (N=10), systolic blood pressure was lower on DASH (113.0+/-1.6) than ULFV (119.0+/-1.8, P<0.05) but not LS-DASH (115.7+/-1.8). Urine F2-isoprostanes, a marker of oxidative stress, were lower in SS subjects on LS-DASH (1.69+/-0.24) than ULFV (3.09+/-0.50, P<0.05) and marginally lower than DASH (2.46+/-0.44, P<0.20). F2-isoprostanes were not different among the three diets in SR volunteers (2.18+/-0.29, 2.06+/-0.29, 2.27+/-0.53, respectively). Aortic augmentation index, a measure of vascular stiffness, was lower in SS subjects on LS-DASH than either DASH or ULFV, and lower on DASH than ULFV in SR volunteers. In SS but not SR subjects, LS-DASH is associated with lower values for F2-isoprostanes and the aortic augmentation index. The results suggest that LS-DASH decreases oxidative stress, improves vascular function and lowers blood pressure in SS but not SR volunteers.

Al-Solaiman Y; Jesri A; Zhao Y; Morrow JD; Egan BM

2009-12-01

304

Adsorção de glifosato sobre solos e minerais Adsorption of glyphosate on soils and minerals  

Directory of Open Access Journals (Sweden)

Full Text Available Glyphosate, an enzyme inhibitor herbicide, has been widely used around the world in agriculture. Dr. John Franz from Monsanto Corporation (USA) discovered glyphosate in 1970. It has been showed that glyphosate is strongly adsorbed by inorganic soil components especially aluminium and iron oxides, and the phosphate group is involved in this interaction. The inactivation of glyphosate in soils can last for days or even months depending on soil characteristics. The addition of phosphate from fertilizers can displace glyphosate from the soils and this could be the cause of decreased productivity of some crops.

Luís R. M. Toni; Henrique de Santana; Dimas A. M. Zaia

2006-01-01

305

Herbicide-resistant weed management: focus on glyphosate.  

Science.gov (United States)

This review focuses on proactive and reactive management of glyphosate-resistant (GR) weeds. Glyphosate resistance in weeds has evolved under recurrent glyphosate usage, with little or no diversity in weed management practices. The main herbicide strategy for proactively or reactively managing GR weeds is to supplement glyphosate with herbicides of alternative modes of action and with soil-residual activity. These herbicides can be applied in sequences or mixtures. Proactive or reactive GR weed management can be aided by crop cultivars with alternative single or stacked herbicide-resistance traits, which will become increasingly available to growers in the future. Many growers with GR weeds continue to use glyphosate because of its economical broad-spectrum weed control. Government farm policies, pesticide regulatory policies and industry actions should encourage growers to adopt a more proactive approach to GR weed management by providing the best information and training on management practices, information on the benefits of proactive management and voluntary incentives, as appropriate. Results from recent surveys in the United States indicate that such a change in grower attitudes may be occurring because of enhanced awareness of the benefits of proactive management and the relative cost of the reactive management of GR weeds. Copyright © 2011 Society of Chemical Industry. PMID:21548004

Beckie, Hugh J

2011-05-05

306

Herbicide-resistant weed management: focus on glyphosate.  

UK PubMed Central (United Kingdom)

This review focuses on proactive and reactive management of glyphosate-resistant (GR) weeds. Glyphosate resistance in weeds has evolved under recurrent glyphosate usage, with little or no diversity in weed management practices. The main herbicide strategy for proactively or reactively managing GR weeds is to supplement glyphosate with herbicides of alternative modes of action and with soil-residual activity. These herbicides can be applied in sequences or mixtures. Proactive or reactive GR weed management can be aided by crop cultivars with alternative single or stacked herbicide-resistance traits, which will become increasingly available to growers in the future. Many growers with GR weeds continue to use glyphosate because of its economical broad-spectrum weed control. Government farm policies, pesticide regulatory policies and industry actions should encourage growers to adopt a more proactive approach to GR weed management by providing the best information and training on management practices, information on the benefits of proactive management and voluntary incentives, as appropriate. Results from recent surveys in the United States indicate that such a change in grower attitudes may be occurring because of enhanced awareness of the benefits of proactive management and the relative cost of the reactive management of GR weeds.

Beckie HJ

2011-09-01

307

Eficácia de glyphosate em plantas de cobertura/ Efficacy of glyphosate in cover crops  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Objetivou-se comparar a eficácia de três dosagens do herbicida glyphosate para a dessecação de Brachiaria decumbens, B. brizantha cv. Marandu e vegetação espontânea, visando a adoção do sistema plantio direto. Utilizou-se delineamento experimental de blocos ao acaso, num esquema fatorial 3 x 3, com quatro repetições. Testaram-se três tipos de cobertura vegetal e três dosagens de glyphosate (1,44, 2,16 e 2,88 kg ha-1). Aos 7, 14, 21 e 28 dias após a aplicaç? (more) ?o (DAA), foram feitas avaliações visuais da porcentagem de controle das coberturas vegetais e, aos 45 DAA, avaliações visuais da porcentagem de reinfestação da área. Conclui-se que, para as espécies que compunham a vegetação espontânea, o uso de 1,44 kg ha-1 proporcionou bom controle, sem no entanto evitar rebrotes de Digitaria insularis. Para as braquiárias, a mesma taxa de controle foi observada a partir de 2,16 kg ha-1. A camada de palha das braquiárias sobre o solo não foi capaz de suprimir a emergência de Cyperus rotundus, Alternanthera tenella, Raphanus raphanistrum, Bidens pilosa e Euphorbia heterophylla. Abstract in english This work aimed to compare rates of glyphosate to desiccate Brachiaria decumbens, B. brizantha cv. Marandu and spontaneous plants (weeds), aiming to adopt the no-tillage system. A randomized block experimental design in a factorial scheme was used (3x3), with four replications. The factors consisted of three species of cover crops and three rates of glyphosate (1.44, 2.16 and 2.88 kg ha-1). At 7, 14, 21 and 28 days after application of the herbicide, visual evaluations of (more) the percentage of cover crop control were carried out and at 45 days of the reinfestation percentage of the area. It was concluded that the spontaneous plants presented a good control at 1.44 kg ha-1, without, however, preventing Digitaria insularis sprouts. The same control rate starting at 2.16 kg ha-1 was observed for the Brachiaria species. The straw layer of these cover crops on the soil was not able to suppress the emergence of Cyperus rotundus, Alternanthera tenella, Raphanus raphanistrum, Bidens pilosa and Euphorbia heterophylla.

Timossi, P.C.; Durigon, J.C.; Leite, G.J.

2006-09-01

308

Momento da chuva após a aplicação e a eficácia dos herbicidas sulfosate e glyphosate aplicados em diferentes formulações Rainfastness and glyphosate and sulfosate efficacy using different formulations  

Directory of Open Access Journals (Sweden)

Full Text Available Com o objetivo de estudar a influência da chuva sobre o desempenho dos herbicidas sulfosate e glyphosate em diferentes formulações, foram conduzidos dois experimentos, um no inverno de 2000 e outro no verão de 2001, na Fazenda Experimental de Ensino e Pesquisa da Faculdade de Ciências Agrárias e Veterinárias, Campus de Jaboticabal-SP. Os experimentos foram instalados segundo o delineamento experimental de blocos ao acaso, com quatro repetições, no arranjo fatorial de 4x5+1, ou seja, quatro tratamentos de herbicidas, cinco períodos sem chuva após a aplicação e uma testemunha, que não recebeu chuva. As formulações de glyphosate foram: SAqC (1,0 L ha-1), GrDA (0,5 kg ha-1), SAqC Transorb (0,75 L ha-1), mais o sulfosate SAqC (1,09 L ha¹). Os períodos sem chuva após a aplicação foram de 1, 2, 4, 6 e > 48 horas. Os herbicidas foram aplicados em pós-emergência das plantas daninhas, utilizando-se de um pulverizador costal, à pressão constante (mantida por ar comprimido) de 30 lbf pol-2. A chuva foi simulada com um sistema de irrigação por aspersão. A lâmina de água variou entre 18 e 19 mm. Em ambas as épocas, a chuva simulada foi prejudicial à ação dos herbicidas, principalmente quando feita nos menores intervalos após a aplicação. Os sintomas de fitointoxicação apareceram mais rapidamente no verão. A formulação Transorb, comercializada como não sendo afetada pela chuva uma hora após a aplicação, não teve o desempenho esperado, tanto no inverno quanto no verão, para períodos de até seis horas sem chuva após a aplicação. O sulfosate apresentou o melhor controle geral das plantas avaliadas, quando se simulou chuva após seis horas, em ambas as épocas. A formulação GrDA foi a mais afetada pela ação da chuva em ambas as épocas.Two field assays were carried out to evaluate the rainfall effects on sulfosate and glyphosate herbicide activity, using different formulations, under two growing seasons (winter and summer). The experiments were conducted at the FCAV/UNESP Experimental Station, Jaboticabel, Brazil, during 2000/01. The formulations were glyphosate SA (1.0 L ha-1), WG (0.5 L ha-1), Transorb (0.75 L ha-1) and sulfosate SA (1.09 L ha-1). In the field, all the trials were arranged in a randomized block experimental design, with four replications. The treatments were arranged in factorial design 5 x 4 + 1 factors, with five periods between the herbicide spraying and the rain incidence (1, 2, 4, 6 and > 48 h), plus one control treatment. The herbicide treatments were applied using a back spraying, with six nozzles DG 11002, spaced by 0.5 m, at 30 p.s.i. constant pression. Artificial rain was provided by a top irrigation system raining 18-19 mm during one hour. The artificial rain reduced glyphosate action, mainly in the shorter periods between herbicide application and the rain incidence. The herbicide symptoms appeared quicker in the summer trials. The Transorb formulation (advertised as not affected by rain one hour after spraying) had the phytointoxication symptoms reduced by the rain up to six hours after spraying, both in the summer and winter. The herbicide sulfosate promoted better control when the rain occurred six hours after spraying, in both seasons.

A.F.F. Pedrinho Júnior; G. Martini; G.V. Felici; F.M. Piva; J.C. Durigan

2002-01-01

309

Momento da chuva após a aplicação e a eficácia dos herbicidas sulfosate e glyphosate aplicados em diferentes formulações/ Rainfastness and glyphosate and sulfosate efficacy using different formulations  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Com o objetivo de estudar a influência da chuva sobre o desempenho dos herbicidas sulfosate e glyphosate em diferentes formulações, foram conduzidos dois experimentos, um no inverno de 2000 e outro no verão de 2001, na Fazenda Experimental de Ensino e Pesquisa da Faculdade de Ciências Agrárias e Veterinárias, Campus de Jaboticabal-SP. Os experimentos foram instalados segundo o delineamento experimental de blocos ao acaso, com quatro repetições, no arranjo fatoria (more) l de 4x5+1, ou seja, quatro tratamentos de herbicidas, cinco períodos sem chuva após a aplicação e uma testemunha, que não recebeu chuva. As formulações de glyphosate foram: SAqC (1,0 L ha-1), GrDA (0,5 kg ha-1), SAqC Transorb (0,75 L ha-1), mais o sulfosate SAqC (1,09 L ha¹). Os períodos sem chuva após a aplicação foram de 1, 2, 4, 6 e > 48 horas. Os herbicidas foram aplicados em pós-emergência das plantas daninhas, utilizando-se de um pulverizador costal, à pressão constante (mantida por ar comprimido) de 30 lbf pol-2. A chuva foi simulada com um sistema de irrigação por aspersão. A lâmina de água variou entre 18 e 19 mm. Em ambas as épocas, a chuva simulada foi prejudicial à ação dos herbicidas, principalmente quando feita nos menores intervalos após a aplicação. Os sintomas de fitointoxicação apareceram mais rapidamente no verão. A formulação Transorb, comercializada como não sendo afetada pela chuva uma hora após a aplicação, não teve o desempenho esperado, tanto no inverno quanto no verão, para períodos de até seis horas sem chuva após a aplicação. O sulfosate apresentou o melhor controle geral das plantas avaliadas, quando se simulou chuva após seis horas, em ambas as épocas. A formulação GrDA foi a mais afetada pela ação da chuva em ambas as épocas. Abstract in english Two field assays were carried out to evaluate the rainfall effects on sulfosate and glyphosate herbicide activity, using different formulations, under two growing seasons (winter and summer). The experiments were conducted at the FCAV/UNESP Experimental Station, Jaboticabel, Brazil, during 2000/01. The formulations were glyphosate SA (1.0 L ha-1), WG (0.5 L ha-1), Transorb (0.75 L ha-1) and sulfosate SA (1.09 L ha-1). In the field, all the trials were arranged in a random (more) ized block experimental design, with four replications. The treatments were arranged in factorial design 5 x 4 + 1 factors, with five periods between the herbicide spraying and the rain incidence (1, 2, 4, 6 and > 48 h), plus one control treatment. The herbicide treatments were applied using a back spraying, with six nozzles DG 11002, spaced by 0.5 m, at 30 p.s.i. constant pression. Artificial rain was provided by a top irrigation system raining 18-19 mm during one hour. The artificial rain reduced glyphosate action, mainly in the shorter periods between herbicide application and the rain incidence. The herbicide symptoms appeared quicker in the summer trials. The Transorb formulation (advertised as not affected by rain one hour after spraying) had the phytointoxication symptoms reduced by the rain up to six hours after spraying, both in the summer and winter. The herbicide sulfosate promoted better control when the rain occurred six hours after spraying, in both seasons.

Pedrinho Júnior, A.F.F.; Martini, G.; Felici, G.V.; Piva, F.M.; Durigan, J.C.

2002-04-01

310

Comparative toxicity of two glyphosate-based formulations to Eisenia andrei under laboratory conditions.  

Science.gov (United States)

Glyphosate-based products are the leading post-emergent agricultural herbicides in the world, particularly in association with glyphosate tolerant crops. However, studies on the effects of glyphosate-based formulations on terrestrial receptors are scarce. This study was conducted to evaluate the comparative toxicity of two glyphosate-based products: Roundup FG (monoammonium salt, 72% acid equivalent, glyphosate-A) and Mon 8750 (monoammonium salt, 85.4% acid equivalent, glyphosate-B), towards the earthworm Eisenia andrei. Median lethal concentration (LC50) showed that glyphosate-A was 4.5-fold more toxic than glyphosate-B. Sublethal concentrations caused a concentration-dependent weight loss, consistent with the reported effect of glyphosate as uncoupler of oxidative phosphorylation. Glyphosate-A showed deleterious effects on DNA and lysosomal damage at concentrations close to the applied environmental concentrations (14.4 ?g ae cm(-2)). With glyphosate-B toxic effects were observed at higher doses, close to its LC50, suggesting that the higher toxicity of formulate A could be attributed to the effects of some of the so-called "inert ingredients", either due to a direct intrinsic toxicity, or to an enhancement in the bioavailability and/or bioaccumulation of the active ingredient. Our results highlight the importance of ecotoxicological assessment not only of the active ingredients, but also of the different formulations usually employed in agricultural practices. PMID:23332878

Piola, Lucas; Fuchs, Julio; Oneto, María Luisa; Basack, Silvana; Kesten, Eva; Casabé, Norma

2013-01-18

311

Comparative toxicity of two glyphosate-based formulations to Eisenia andrei under laboratory conditions.  

UK PubMed Central (United Kingdom)

Glyphosate-based products are the leading post-emergent agricultural herbicides in the world, particularly in association with glyphosate tolerant crops. However, studies on the effects of glyphosate-based formulations on terrestrial receptors are scarce. This study was conducted to evaluate the comparative toxicity of two glyphosate-based products: Roundup FG (monoammonium salt, 72% acid equivalent, glyphosate-A) and Mon 8750 (monoammonium salt, 85.4% acid equivalent, glyphosate-B), towards the earthworm Eisenia andrei. Median lethal concentration (LC50) showed that glyphosate-A was 4.5-fold more toxic than glyphosate-B. Sublethal concentrations caused a concentration-dependent weight loss, consistent with the reported effect of glyphosate as uncoupler of oxidative phosphorylation. Glyphosate-A showed deleterious effects on DNA and lysosomal damage at concentrations close to the applied environmental concentrations (14.4 ?g ae cm(-2)). With glyphosate-B toxic effects were observed at higher doses, close to its LC50, suggesting that the higher toxicity of formulate A could be attributed to the effects of some of the so-called "inert ingredients", either due to a direct intrinsic toxicity, or to an enhancement in the bioavailability and/or bioaccumulation of the active ingredient. Our results highlight the importance of ecotoxicological assessment not only of the active ingredients, but also of the different formulations usually employed in agricultural practices.

Piola L; Fuchs J; Oneto ML; Basack S; Kesten E; Casabé N

2013-04-01

312

Glyphosate translocation in hairy fleabane (Conyza bonariensis) biotypes Translocação do glyphosate em biótipos de buva (Conyza bonariensis)  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this work was to evaluate the translocation of glyphosate in C. bonariensis plants resistant and susceptible to that herbicide. The 14C-glyphosate was mixed with commercial gyhphosate (800 g ha-1) and applied on the center of the adaxial face of a third node leaf, using a micro syringe, and adding 10 µL of a solution with specific activity of 1,400 Bq, 45 days after plant emergence. The concentration of the glyphosate translocated in the plant was evaluated at time intervals of 6, 12, 36 and 72 hours after being applied on the application leaf, stem, roots and leaves. Ten hours after treatment application, the distribution of the product in the application leaf, divided into base, center and apex, was also evaluated by measuring the radiation emitted by 14C-glyphosate in a liquid scintillation spectrometer. Greater glyphosate retention was observed in the resistant biotype leaf, approximately 90% of the total absorbed up to 72 hours. In the susceptible biotype, this value was close to 70% in the same period. Susceptible biotype leaves, stem and roots showed greater concentration of glyphosate, indicating greater translocation efficiency in this biotype. In the resistant biotype, the herbicide accumulated in greater quantity at the apex and center of the application leaf, while in the susceptible biotype greater accumulation was observed at the base and center leaf. Thus, it can be stated that the resistance mechanism is related to the differential translocation of this herbicide in the biotypes.Objetivou-se com este trabalho avaliar a translocação do glyphosate em plantas de C. bonariensis resistentes e suscetíveis a esse herbicida. Para isso aplicou-se o 14C-glyphosate em mistura com glyphosate comercial (800 g ha-1) sobre o centro da face adaxial da folha do terceiro nó, utilizando-se uma microsseringa, adicionando-se 10 µL da calda com atividade específica de 1.400 Bq, aos 45 dias após a emergência da buva. A concentração de glyphosate translocado na planta foi avaliada em intervalos de tempo de 6, 12, 36 e 72 horas após a aplicação, na folha de aplicação, no caule, nas raízes e nas folhas. Dez horas após a aplicação dos tratamentos (HAT) avaliou-se também a distribuição do produto na folha de aplicação, dividida em base, centro e ápice. As avaliações foram realizadas por meio da medição da radiação emitida pelo 14C-glyphosate, em espectrômetro de cintilação líquida. Maior retenção de glyphosate foi observada na folha tratada do biótipo resistente, aproximadamente 90 % do total absorvido até as 72 horas. No biótipo suscetível esse valor foi de cerca de 70 % no mesmo período. Nas folhas, no caule e nas raízes, a maior concentração do glyphosate absorvido foi encontrada no biótipo suscetível, indicando maior eficiência de translocação neste biótipo. No biótipo resistente o herbicida se acumulou em maior quantidade no ápice e no centro da folha de aplicação e no suscetível observou-se maior acúmulo na base e no centro da mesma folha. Desta forma, pode-se afirmar que o mecanismo de resistência está relacionado à translocação diferencial deste herbicida nos biótipos.

E.A. Ferreira; L. Galon; I. Aspiazú; A.A. Silva; G. Concenço; A.F. Silva; J.A. Oliveira; L. Vargas

2008-01-01

313

Degradation of the Herbicide Glyphosate by Members of the Family Rhizobiaceae.  

Science.gov (United States)

Several strains of the family Rhizobiaceae were tested for their ability to degrade the phosphonate herbicide glyphosate (isopropylamine salt of N-phosphonomethylglycine). All organisms tested (seven Rhizobium meliloti strains, Rhizobium leguminosarum, Rhizobium galega, Rhizobium trifolii, Agrobacterium rhizogenes, and Agrobacterium tumefaciens) were able to grow on glyphosate as the sole source of phosphorus in the presence of the aromatic amino acids, although growth on glyphosate was not as fast as on P(i). These results suggest that glyphosate degradation ability is widespread in the family Rhizobiaceae. Uptake and metabolism of glyphosate were studied by using R. meliloti 1021. Sarcosine was found to be the immediate breakdown product, indicating that the initial cleavage of glyphosate was at the C-P bond. Therefore, glyphosate breakdown in R. meliloti 1021 is achieved by a C-P lyase activity. PMID:16348512

Liu, C-M; McLean, P A; Sookdeo, C C; Cannon, F C

1991-06-01

314

Degradation of the Herbicide Glyphosate by Members of the Family Rhizobiaceae.  

UK PubMed Central (United Kingdom)

Several strains of the family Rhizobiaceae were tested for their ability to degrade the phosphonate herbicide glyphosate (isopropylamine salt of N-phosphonomethylglycine). All organisms tested (seven Rhizobium meliloti strains, Rhizobium leguminosarum, Rhizobium galega, Rhizobium trifolii, Agrobacterium rhizogenes, and Agrobacterium tumefaciens) were able to grow on glyphosate as the sole source of phosphorus in the presence of the aromatic amino acids, although growth on glyphosate was not as fast as on P(i). These results suggest that glyphosate degradation ability is widespread in the family Rhizobiaceae. Uptake and metabolism of glyphosate were studied by using R. meliloti 1021. Sarcosine was found to be the immediate breakdown product, indicating that the initial cleavage of glyphosate was at the C-P bond. Therefore, glyphosate breakdown in R. meliloti 1021 is achieved by a C-P lyase activity.

Liu CM; McLean PA; Sookdeo CC; Cannon FC

1991-06-01

315

Resposta de biótipos de Euphorbia heterophylla a doses de glyphosate/ Response of Euphorbia heterophylla biotypes to glyphosate rates  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A leiteira (Euphorbia heterophylla) é uma planta daninha de ciclo anual encontrada com frequência em lavouras de soja na região Sul do Brasil, controlada em lavouras de soja geneticamente modificada (Roundup Ready® - RR) com uso do herbicida glyphosate. Entretanto, nos últimos anos, o controle dessa espécie não tem sido satisfatório em alguns locais, provocando a suspeita de que foram selecionados biótipos resistentes ao herbicida. Diante disso, o objetivo deste (more) trabalho foi avaliar, por meio de curvas de dose-resposta, biótipos de leiteira com suspeita de resistência ao glyphosate. O experimento foi realizado em casa de vegetação, em delineamento experimental completamente casualizado, com quatro repetições. Os tratamentos constituíram-se de doses crescentes de glyphosate (0, 90, 180, 360, 720, 1.080, 1.440 e 2.160 g e.a. ha-1), aplicadas sobre cinco biótipos de leiteira, oriundos de lavouras de soja RR do Estado do Rio Grande do Sul. As variáveis avaliadas foram controle e matéria seca da parte aérea. Os resultados evidenciam que os biótipos de leiteira avaliados são suscetíveis ao glyphosate. Abstract in english Wild poinsettia is an annual cycle weed, commonly found in soybean crop in southern Brazil. It is controlled by glyphosate in genetically- modified soybean (Roundup Ready® - RR). The control of this species has not proven to be satisfactory in some places in the last years, leading to the suspicion that biotypes resistant to glyphosate have been selected. The objective this work was to evaluate, by response-dose curve, wild poinsettia biotypes with suspected resistance t (more) o glyphosate. The experiment was conducted under greenhouse conditions and the experiment was arranged in a randomized complete block design, with four replications. The treatments consisted of increased application rates of glyphosate (0, 90, 180, 360, 720, 1,080, 1,440 and 2,160 g a.e. ha-1) on five wild poinsettia biotypes, from crop soybean RR in the state of Rio Grande do Sul. Control and dry weight were evaluated. The results indicated that the wild poinsettia biotypes are susceptible to glyphosate.

Vargas, L; Nohatto, M.A; Agostinetto, D; Bianchi, M.A; Gonçalves, E.M; Toledo, R.E

2011-01-01

316

Tolerância do Tifton 85 ao glyphosate em diferentes épocas de aplicação Tifton 85 tolerance to glyphosate at different application times  

Directory of Open Access Journals (Sweden)

Full Text Available O Tifton 85 é uma forrageira de alto valor nutritivo, recomendada para pastejo, fenação e silagem, podendo ser considerada uma espécie daninha, principalmente em áreas de cultivos agrícolas e produção de sementes de outras forrageiras, devido a sua fácil propagação e seu rápido desenvolvimento. Este experimento foi proposto com o objetivo de avaliar a tolerância de plantas de Tifton 85 a doses crescentes de glyphosate em duas épocas diferentes. O experimento foi conduzido em vasos de polietileno com capacidade de 10 L, em delineamento experimental de blocos casualizados, no esquema fatorial 2 x 8, sendo duas épocas de aplicação (inverno e verão) e oito doses de glyphosate (0, 270, 540, 1.080, 2.160, 3.240, 4.320 e 5.400 g ha-1), com quatro repetições. Para cada época de aplicação, o controle das plantas de Tifton 85 foi feito aos 15, 30 e 60 DAA (dias após aplicação). Obteve-se controle superior a 90% de Tifton 85 a partir de 2.636,72 g ha-1 de glyphosate em aplicação realizada no inverno e de 3.607,03 g ha-1 em aplicação no verão. Os resultados evidenciaram a alta tolerância do Tifton 85 ao glyphosate e o maior controle das plantas expostas a esse herbicida em épocas mais frias do ano (inverno), quando em comparação com as plantas expostas ao herbicida no verão.Tifton 85 is a type of forage of high nutritive value, recommended for grazing or hay and silage production. It can be considered a weed, mainly in agricultural and forage seed production areas, probably due to its easy propagation and fast development. Thus, this experiment aimed to evaluate Tifton 85 tolerance to increasing levels of glyphosate during two different seasons. The experiment was arranged in a completely randomized block design with four replications in a 2 x 8 factorial arrangement, and pulverization in two seasons (winter and summer) and eight glyphosate levels (0; 270; 540; 1,080; 2,160; 3,240; 4,320; and 5,400 g ha-1). The experiment was carried out in polyethylene pots with 10L capacity. For each season, control of the Tifton 85 plants was performed at 15, 30 and 60 DAA (days after application). Around 90% of Tifton 85 plant control was observed with 2,636.72 g ha-1 of glyphosate in the winter and 3,607.03 g ha-1 of glyphosate in the summer. The results obtained showed that Tifton 85 is highly tolerant to glyphosate and control is more efficient in the winter than in the summer.

M.V. Santos; F.C.L. Freitas; F.A. Ferreira; A.J. Carvalho; T.G.S. Braz; J. Cavali; O.L. Rodrigues

2010-01-01

317

Effects of glyphosate and endosulfan on soil microorganisms in soybean crop Efeitos do endosulfan e glyphosate sobre microrganismos do solo na cultura da soja  

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Full Text Available Transgenic soybean, resistant to glyphosate, is the most dominant transgenic crop grown commercially in the world. Research works on herbicide and insecticide mixtures and their effects on microorganisms are rarely reported. This work aimed to study the impact of glyphosate, endosulfan and their mixtures on the microbial soil activity in soybean crop. The experiment was carried out in a complete randomized block design with four treatments and five replications. The treatments were glyphosate 480 SL [540 g of active ingredient (a.i.) ha-1], endosulfan 350 EC (525 g a.i. ha-1), the glyphosate 480 SL [540 g of active ingredient (a.i.) ha-1] mixed with endosulfan 350 EC (525 g a.i. ha-1) and the control. Microbial activity was evaluated five days after treatment application. Glyphosate application was not an impacting factor for soil CO2 production. Endosulfan application (alone or mixed with glyphosate) suppressed CO2 production by microorganisms in the soil. Microbial biomass and microbial quotient were lower in the treatments using endosulfan alone and in those using endosulfan mixed with glyphosate than in the treatments using glyphosate alone and control.A soja resistente ao glyphosate é a cultura transgênica mais cultivada em todo o mundo. Pesquisas envolvendo o impacto de mistura de herbicidas e inseticidas e seus efeitos sobre microrganismos do solo são raramente reportadas. Este trabalho teve por objetivo avaliar o impacto do herbicida (glyphosate), do inseticida (endosulfan) e da mistura de ambos sobre a atividade microbiana do solo na cultura da soja. O delineamento experimental foi em blocos casualizados, com quatro tratamentos e cinco repetições. Os tratamentos foram o herbicida glyphosate 480 SL [540 g de ingrediente ativo (i.a.) ha-1], endosulfan 350 EC (525 g i.a. ha-1), a mistura de glyphosate 480 SL (540 g de i.a. ha-1) com endosulfan 350 EC (525 g i.a. ha-1) e a testemunha onde se aplicou água. A atividade microbiana foi avaliada aos cinco dias após a aplicação dos tratamentos. A aplicação de glyphosate não afetou a produção de CO2 pela microbiota do solo. A aplicação de endosulfan (isolado ou em mistura com o glyphosate) reduziu a produção de CO2 pelos microrganismos do solo. A biomassa microbiana e o quociente metabólico foram menores nos tratamentos submetidos à aplicação de endosulfan isolado e em mistura com glyphosate, em comparação àqueles submetidos à aplicaçao de glyphosate isolado e à testemunha.

J.L. Pereira; M.C. Picanço; A.A. Silva; E.A. Santos; H.V.V. Tomé; J.B. Olarte

2008-01-01

318

Glyphosate resistance by engineering the flavoenzyme glycine oxidase.  

UK PubMed Central (United Kingdom)

Glycine oxidase from Bacillus subtilis is a homotetrameric flavoprotein of great potential biotechnological use because it catalyzes the oxidative deamination of various amines and d-isomer of amino acids to yield the corresponding alpha-keto acids, ammonia/amine, and hydrogen peroxide. Glyphosate (N-phosphonomethylglycine), a broad spectrum herbicide, is an interesting synthetic amino acid: this compound inhibits 5-enolpyruvylshikimate-3-phosphate synthase in the shikimate pathway, which is essential for the biosynthesis of aromatic amino acids in plants and certain bacteria. In recent years, transgenic crops resistant to glyphosate were mainly generated by overproducing the plant enzyme or by introducing a 5-enolpyruvylshikimate-3-phosphate synthase insensitive to this herbicide. In this work, we propose that the enzymatic oxidation of glyphosate could be an effective alternative to this important biotechnological process. To reach this goal, we used a rational design approach (together with site saturation mutagenesis) to generate a glycine oxidase variant more active on glyphosate than on the physiological substrate glycine. The glycine oxidase containing three point mutations (G51S/A54R/H244A) reaches an up to a 210-fold increase in catalytic efficiency and a 15,000-fold increase in the specificity constant (the k(cat)/K(m) ratio between glyphosate and glycine) as compared with wild-type glycine oxidase. The inspection of its three-dimensional structure shows that the alpha2-alpha3 loop (comprising residues 50-60 and containing two of the mutated residues) assumes a novel conformation and that the newly introduced residue Arg(54) could be the key residue in stabilizing glyphosate binding and destabilizing glycine positioning in the binding site, thus increasing efficiency on the herbicide.

Pedotti M; Rosini E; Molla G; Moschetti T; Savino C; Vallone B; Pollegioni L

2009-12-01

319

Glyphosate resistance by engineering the flavoenzyme glycine oxidase.  

Science.gov (United States)

Glycine oxidase from Bacillus subtilis is a homotetrameric flavoprotein of great potential biotechnological use because it catalyzes the oxidative deamination of various amines and d-isomer of amino acids to yield the corresponding alpha-keto acids, ammonia/amine, and hydrogen peroxide. Glyphosate (N-phosphonomethylglycine), a broad spectrum herbicide, is an interesting synthetic amino acid: this compound inhibits 5-enolpyruvylshikimate-3-phosphate synthase in the shikimate pathway, which is essential for the biosynthesis of aromatic amino acids in plants and certain bacteria. In recent years, transgenic crops resistant to glyphosate were mainly generated by overproducing the plant enzyme or by introducing a 5-enolpyruvylshikimate-3-phosphate synthase insensitive to this herbicide. In this work, we propose that the enzymatic oxidation of glyphosate could be an effective alternative to this important biotechnological process. To reach this goal, we used a rational design approach (together with site saturation mutagenesis) to generate a glycine oxidase variant more active on glyphosate than on the physiological substrate glycine. The glycine oxidase containing three point mutations (G51S/A54R/H244A) reaches an up to a 210-fold increase in catalytic efficiency and a 15,000-fold increase in the specificity constant (the k(cat)/K(m) ratio between glyphosate and glycine) as compared with wild-type glycine oxidase. The inspection of its three-dimensional structure shows that the alpha2-alpha3 loop (comprising residues 50-60 and containing two of the mutated residues) assumes a novel conformation and that the newly introduced residue Arg(54) could be the key residue in stabilizing glyphosate binding and destabilizing glycine positioning in the binding site, thus increasing efficiency on the herbicide. PMID:19864430

Pedotti, Mattia; Rosini, Elena; Molla, Gianluca; Moschetti, Tommaso; Savino, Carmelinda; Vallone, Beatrice; Pollegioni, Loredano

2009-10-28

320

Glyphosate Resistance by Engineering the Flavoenzyme Glycine Oxidase*  

Science.gov (United States)

Glycine oxidase from Bacillus subtilis is a homotetrameric flavoprotein of great potential biotechnological use because it catalyzes the oxidative deamination of various amines and d-isomer of amino acids to yield the corresponding ?-keto acids, ammonia/amine, and hydrogen peroxide. Glyphosate (N-phosphonomethylglycine), a broad spectrum herbicide, is an interesting synthetic amino acid: this compound inhibits 5-enolpyruvylshikimate-3-phosphate synthase in the shikimate pathway, which is essential for the biosynthesis of aromatic amino acids in plants and certain bacteria. In recent years, transgenic crops resistant to glyphosate were mainly generated by overproducing the plant enzyme or by introducing a 5-enolpyruvylshikimate-3-phosphate synthase insensitive to this herbicide. In this work, we propose that the enzymatic oxidation of glyphosate could be an effective alternative to this important biotechnological process. To reach this goal, we used a rational design approach (together with site saturation mutagenesis) to generate a glycine oxidase variant more active on glyphosate than on the physiological substrate glycine. The glycine oxidase containing three point mutations (G51S/A54R/H244A) reaches an up to a 210-fold increase in catalytic efficiency and a 15,000-fold increase in the specificity constant (the kcat/Km ratio between glyphosate and glycine) as compared with wild-type glycine oxidase. The inspection of its three-dimensional structure shows that the ?2-?3 loop (comprising residues 50–60 and containing two of the mutated residues) assumes a novel conformation and that the newly introduced residue Arg54 could be the key residue in stabilizing glyphosate binding and destabilizing glycine positioning in the binding site, thus increasing efficiency on the herbicide.

Pedotti, Mattia; Rosini, Elena; Molla, Gianluca; Moschetti, Tommaso; Savino, Carmelinda; Vallone, Beatrice; Pollegioni, Loredano

2009-01-01

 
 
 
 
321

Time-integrated sampling of glyphosate in natural waters.  

Science.gov (United States)

Environmental monitoring of pesticide residues in surface water is often done with time-integrated sampling where a specified volume is sampled each hour during, e.g., a week, thus avoiding at momentary high or low extreme concentrations. However, sampling over an extended period of time can result in losses of easily degradable analytes, why the stability of the target analytes over the timespan of the sampling must be checked. Glyphosate is one of the most widely used herbicides. Because of its chemical complexity, glyphosate binds differently to metals and colloids at different pH, and the degradation may also be affected. Recovery of glyphosate from spiked natural waters after 1 and 3 weeks of storage was higher when the samples were acidified to approximately pH 2 rather than at their natural pH. Keeping the samples refrigerated to 4°C in darkness also enhanced recovery, while glyphosate losses were substantial from samples kept at their natural pH at 20 °C. Total loss of glyphosate was observed in some samples kept at natural pH, 20 °C, and daylight; a loss partly due to binding to metals or colloids that could only partially be reversed by acidification. For 1-week time-integrated sampling a small amount of hydrochloric acid in a piece of heat-sealed hydrophobic micro-porous tubing is added to the sampling bottles before deployment, a procedure that acidifies the samples during collection keeping them below pH 2 until analysis, thus minimising losses of glyphosate. The method also allows determination of the primary degradation product aminomethylphosphonic acid (AMPA). PMID:23044352

Kylin, H

2012-10-06

322

Time-integrated sampling of glyphosate in natural waters.  

UK PubMed Central (United Kingdom)

Environmental monitoring of pesticide residues in surface water is often done with time-integrated sampling where a specified volume is sampled each hour during, e.g., a week, thus avoiding at momentary high or low extreme concentrations. However, sampling over an extended period of time can result in losses of easily degradable analytes, why the stability of the target analytes over the timespan of the sampling must be checked. Glyphosate is one of the most widely used herbicides. Because of its chemical complexity, glyphosate binds differently to metals and colloids at different pH, and the degradation may also be affected. Recovery of glyphosate from spiked natural waters after 1 and 3 weeks of storage was higher when the samples were acidified to approximately pH 2 rather than at their natural pH. Keeping the samples refrigerated to 4°C in darkness also enhanced recovery, while glyphosate losses were substantial from samples kept at their natural pH at 20 °C. Total loss of glyphosate was observed in some samples kept at natural pH, 20 °C, and daylight; a loss partly due to binding to metals or colloids that could only partially be reversed by acidification. For 1-week time-integrated sampling a small amount of hydrochloric acid in a piece of heat-sealed hydrophobic micro-porous tubing is added to the sampling bottles before deployment, a procedure that acidifies the samples during collection keeping them below pH 2 until analysis, thus minimising losses of glyphosate. The method also allows determination of the primary degradation product aminomethylphosphonic acid (AMPA).

Kylin H

2013-02-01