Effect of glyphosate on symbiotic N₂ fixation and nickel concentration in glyphosate-resistant soybeans

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment ecosystems & environment, 2010-02, Vol.44 (2), p.176-180
• Main Authors: Zobiole, L.H.S, Oliveira, R.S, Kremer, R.J, Constantin, J, Yamada, T, Castro, C, Oliveira, F.A, Oliveira, A
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; Fundamental and applied biological sciences. Psychology; Glycine max; glyphosate; herbicide resistance; nickel; nitrogen fixation; photosynthesis; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Soil science; soybeans; symbiosis
• ISSN: 0929-1393; 1873-0272
• DOI: 10.1016/j.apsoil.2009.12.003

Decreased biological nitrogen fixation in glyphosate-resistant (GR) soybeans has been attributed directly to toxicity of glyphosate or its metabolites, to N₂-fixing microorganisms. As a strong metal chelator, glyphosate could influence symbiotic N₂ fixation by lowering the concentration of nickel (Ni) that is essential for the symbiotic microorganisms. Evaluation of different cultivars grown on different soil types at the State University of Maringá, PR, Brazil during the summer 2008 revealed, significant decreases in photosynthetic parameters (chlorophyll, photosynthetic rate, transpiration and stomatal conductance) and nickel content with glyphosate use (single or sequential application). This work demonstrated that glyphosate can influence the symbiotic N₂ fixation by lowering nickel content available to the symbiotic microorganisms.