Manganese uptake and redistribution in soybean as affected by glyphosate

Abstract

Detrimental effects of glyphosate on plant mineral nutrition have been reported in the literature, particularly on Mn uptake and redistribution. However, in most of the experiments conducted so far glyphosate-susceptible plants were used. Effects of glyphosate on Mn absorption kinetics, accumulation, and distribution within the plant, as well as soybean response to Mn as affected by glyphosate were studied in three experiments. In the first experiment, in nutrient solution, the effect of glyphosate on soybean Mn uptake kinetic parameters (Imax, Km and Cmin) was determined. In a second experiment, also in nutrient solution, differential Mn accumulation and distribution were studied for a conventional soybean cultivar and its near-isogenic glyphosate-resistant counterpart as affected by glyphosate. In a third experiment, response of glyphosate-resistant soybean cultivars to Mn application was studied in the presence of glyphosate, in pots with Mn-deficient soil. Maximum Mn influx (Imax) was higher in the herbicide-resistant (GR) cultivar than in its conventional counterpart. Glyphosate applied to nutrient solution at low rates decreased Km and Cmin. A few days after herbicide treatment, RR soybean plants developed yellowish leaves, a symptom which, in the field, could be misinterpreted as Mn deficiency, but herbicide application had no effect on Mn uptake or distribution within the plant. In the soil experiment, soybean Mn uptake was increased by Mn application, with no effect of glyphosate. Under greenhouse conditions, there was no evidence of deleterious effects of glyphosate on Mn absorption, accumulation and distribution in the plant and on soybean cultivars response to Mn application.

Effect of ammonium sulfate and water hardness on glyphosate and glufosinate activity in corn

“…The 2002 Purdue study included several RR varieties and found that not all RR varieties were responsive to Mn, suggesting that the Mn response is not directly linked to the RR trait. Research in California found no evidence that the RR trait affected Mn relations (Rosolem et al 2009). Research in Brazil found 1 out of 3 RR varieties had lower Mn concentrations in new leaves than the non-RR parental line, but the other two varieties were not affected (Zobiole et al 2010).…”

“…They also reported significant reductions in shoot and root biomass due to the glyphosate applications, something that is normally not observed. However, the majority of research has not identified differences in Mn absorption, accumulation and availability between glyphosate-treated and non-treated RR soybean (Bott et al 2008;Rosolem et al 2009;Nelson 2009). Rosolem et al (2009) stated that glyphosate injury symptoms in RR soybean have been misinterpreted as Mn deficiency.…”

“…However, the majority of research has not identified differences in Mn absorption, accumulation and availability between glyphosate-treated and non-treated RR soybean (Bott et al 2008;Rosolem et al 2009;Nelson 2009). Rosolem et al (2009) stated that glyphosate injury symptoms in RR soybean have been misinterpreted as Mn deficiency. Ebelhar and Hart (2006) in Illinois were unable to prevent chlorosis associated with glyphosate by supplementing soybean with additional Mn, nor prevent yield loss associated with high glyphosate rates (2X-4X) with supplemental Mn.…”

Short-term phyto-toxicity consequences of a non-selective herbicide glyphosate (Roundup) on the growth of onions (Allium cepa Linn.)

“…It has been proposed that glyphosate interferes with absorption and utilization of Mn, thus increasing a plants susceptibility to disease. However, the majority of research has not found reductions in Mn concentrations within plants following glyphosate applications (Bott et al, 2008;Nelson, 2009;Rosolem et al, 2009). From the discussion above, it is apparent that the use of herbicides in the environment has negative impacts on onion cells and likely soil nutrients which might affect the growth and yield of onions as well as other similar plant species (Kellogg et al, 2000;Cavusoglu et al, 2011).…”

Efeitos de doses e épocas de aplicação de manganês via foliar no cultivo de soja convencional e em derivada transgênica RR

“…Zobiole et al (2010) Rosolem et al (2010), que em condições controladas, não encontraram evidências de efeitos negativos do glifosato na absorção, acúmulo e distribuição do Mn na soja RR e que a transgenia RR não levou a mudanças significativas na resposta da planta a este elemento. Para Stefanello et al (2011) a aplicação de glifosato na soja transgênica RR não apresentou efeito nos teores foliares de nutrientes.…”