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

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• 作者：Selim Eker ; Levent Ozturk ; Atilla Yazici ; Bulent Erenoglu ; Volker Romheld ; Ismail Cakmak
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2006
• 出版时间：December 27, 2006
• 年：2006
• 卷：54
• 期：26
• 页码：10019 - 10025
• 全文大小：233K
• 年卷期：v.54,no.26(December 27, 2006)
• ISSN：1520-5118

文摘

Evidence clearly shows that cationic micronutrients in spray solutions reduce the herbicidaleffectiveness 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 micronutrientnutrition of nontarget plants when exposed to glyphosate drift or glyphosate residues in soil. In thepresent 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 controlledenvironmental conditions. Glyphosate was sprayed on plant shoots at different rates between 1.25and 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 chlorophyllconcentrations of young leaves and shoot tips. The basal parts of the youngest leaves and shoottips 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 theconcentration of Zn and Cu was less affected. In short-term uptake experiments with radiolabeledFe (⁵⁹Fe), Mn (⁵⁴Mn), and Zn (⁶⁵Zn), root uptake of ⁵⁹Fe and ⁵⁴Mn was significantly reduced in 12and 24 h after application of 6% of the recommended dosage of glyphosate, respectively. Glyphosateresulted in almost complete inhibition of root-to-shoot translocation of ⁵⁹Fe within 12 h and ⁵⁴Mnwithin 24 h after application. These results suggest that glyphosate residues or drift may result insevere impairments in Fe and Mn nutrition of nontarget plants, possibly due to the formation of poorlysoluble glyphosate-metal complexes in plant tissues and/or rhizosphere interactions.