Plants as sources of cations antagonistic to glyphosate activity

Hall, Gavin J.; Hart, Clifford A; Jones, Ceris A

doi:10.1002/(sici)1526-4998(200004)56:4<351::aid-ps151>3.0.co;2-a

Cited by 66 publications

(10 citation statements)

References 41 publications

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“…The treated leaf was washed with 5 ml of an acidified (pH 1.5) washing solution (0.1 M HCl plus methanol, 50:50 by volume) in a 20-ml glass vial for 15 s to remove unabsorbed herbicide. The acid washing regime was used to effectively remove poorly soluble salts of glyphosate that might form on the leaf surface as described by Hall et al (2000). A 1-ml subsample of the washing solutions was mixed with 15-ml of Ready Safe TM (Beckman Coulter Inc, Fullerton, CA, USA) cocktail and radioactivity was quantified using an LS 6000 SC liquid scintillation counter (Beckman Coulter Inc) to determine 14 C-glyphosate leaf uptake.…”

Section: Petri Dish Dose-response Bioassaymentioning

confidence: 99%

Investigating the mechanisms of glyphosate resistance in Lolium multiflorum

Perez‐Jones

Park

Polge

et al. 2007

Planta

163

191

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Evolved resistance to the herbicide glyphosate has been reported in eleven weed species, including Lolium multiflorum. Two glyphosate-resistant L. multiflorum populations were collected, one from Chile (SF) and one from Oregon, USA (OR), and the mechanisms conferring glyphosate resistance were studied. Based on a Petri dish dose-response bioassay, the OR and the SF populations were two and fivefold more resistant to glyphosate when compared to the susceptible (S) population, respectively; however, based on a whole-plant dose-response bioassay, both OR and SF populations were fivefold more resistant to glyphosate than the S population, implying that different resistance mechanisms might be involved. The S population accumulated two and three times more shikimic acid in leaf tissue 96 h after glyphosate application than the resistant OR and SF populations, respectively. There were no differences between the S and the glyphosate-resistant OR and SF populations in 14C-glyphosate leaf uptake; however, the patterns of 14C-glyphosate translocation were significantly different. In the OR population, a greater percentage of 14C-glyphosate absorbed by the plant moved distal to the treated section and accumulated in the tip of the treated leaf. In contrast, in the S and in the SF populations, a greater percentage of 14C-glyphosate moved to non-treated leaves and the stem. cDNA sequence analysis of the EPSP synthase gene indicated that the glyphosate-resistant SF population has a proline 106 to serine amino acid substitution. Here, we report that glyphosate resistance in L. multiflorum is conferred by two different mechanisms, limited translocation (nontarget site-based) and mutation of the EPSP synthase gene (target site-based).

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Section: Petri Dish Dose-response Bioassaymentioning

confidence: 99%

Investigating the mechanisms of glyphosate resistance in Lolium multiflorum

Perez‐Jones

Park

Polge

et al. 2007

Planta

163

191

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“…The nature of this antagonism between micronutrients and glyphosate is not known. Possibly, it is related to the formation of insoluble glyphosate complexes with cationic micronutrients (19,20). Iron and Mn in spray solutions are known to inhibit glyphosate herbicidal activity by limiting absorption and translocation of glyphosate in treated leaves.…”

Section: Introductionmentioning

confidence: 99%

“…After absorption of glyphosate into the plant, the uptake and transport of cationic micronutrients may also be limited due to the formation of poorly soluble glyphosate-metal complexes within plant tissues. The antagonism between cationic mineral nutrients and glyphosate has been studied primarily in terms of impaired leaf absorption (penetration) and limited translocation of glyphosate to explain reduced effectiveness of glyphosate to kill target plants (19)(20)(21)(22)(23)(24). In sunflower and velvetleaf plants, cationic nutrients such as Mn, Fe, and Ca bind to the glyphosate molecule via its carboxyl and phosphonate groups to form stable complexes with glyphosate (20,22,23).…”

Section: Introductionmentioning

confidence: 99%

Foliar-Applied Glyphosate Substantially Reduced Uptake and Transport of Iron and Manganese in Sunflower (Helianthus annuus L.) Plants

Eker

Öztürk

Yazıcı

et al. 2006

J. Agric. Food Chem.

151

104

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Evidence clearly shows that cationic micronutrients in spray solutions reduce the herbicidal effectiveness of glyphosate for weed control due to the formation of metal-glyphosate complexes. The formation of these glyphosate-metal complexes in plant tissue may also impair micronutrient nutrition of nontarget plants when exposed to glyphosate drift or glyphosate residues in soil. In the present study, the effects of simulated glyphosate drift on plant growth and uptake, translocation, and accumulation (tissue concentration) of iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) were investigated in sunflower (Helianthus annuus L.) plants grown in nutrient solution under controlled environmental conditions. Glyphosate was sprayed on plant shoots at different rates between 1.25 and 6.0% of the recommended dosage (i.e., 0.39 and 1.89 mM glyphosate isopropylamine salt). Glyphosate applications significantly decreased root and shoot dry matter production and chlorophyll concentrations of young leaves and shoot tips. The basal parts of the youngest leaves and shoot tips were severely chlorotic. These effects became apparent within 48 h after the glyphosate spray. Glyphosate also caused substantial decreases in leaf concentration of Fe and Mn while the concentration of Zn and Cu was less affected. In short-term uptake experiments with radiolabeled Fe (59Fe), Mn (54Mn), and Zn (65Zn), root uptake of 59Fe and 54Mn was significantly reduced in 12 and 24 h after application of 6% of the recommended dosage of glyphosate, respectively. Glyphosate resulted in almost complete inhibition of root-to-shoot translocation of 59Fe within 12 h and 54Mn within 24 h after application. These results suggest that glyphosate residues or drift may result in severe impairments in Fe and Mn nutrition of nontarget plants, possibly due to the formation of poorly soluble glyphosate-metal complexes in plant tissues and/or rhizosphere interactions.

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“…Glyphosate is most effective when applied at low spray volumes with a surfactant (Ramsdale et al 2003 ). Divalent cations such as calcium can interact with glyphosate preventing its penetration into the leaf (Hall et al 2000 ;Thelen et al 1995 ). The addition of ammonium sulfate can overcome this antagonism and is often added to the spray solutions (Thelen et al 1995 ).…”

mentioning

confidence: 99%

Testing Methods for Glyphosate Resistance

Shaner

2010

Glyphosate Resistance in Crops and Weeds

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Plants as sources of cations antagonistic to glyphosate activity

Cited by 66 publications

References 41 publications

Investigating the mechanisms of glyphosate resistance in Lolium multiflorum

Investigating the mechanisms of glyphosate resistance in Lolium multiflorum

Foliar-Applied Glyphosate Substantially Reduced Uptake and Transport of Iron and Manganese in Sunflower (Helianthus annuus L.) Plants

Testing Methods for Glyphosate Resistance

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