Salicylic Acid Pretreatment Modulates Wheat Responses to Glyphosate

Abstract

Glyphosate is an extensively used herbicide because of its non-selective action for weed control. Salicylic acid (SA) is a phenolic compound that has the potential to increase plant tolerance to diverse stresses. To test SA ability to modulate plant responses to glyphosate we used young wheat (Triticum aestivum L.) seedlings grown as a water culture. Plants were sprayed with 1 mM SA, and 24 h later with 0.5 mM glyphosate. All measurements were performed 14 days after herbicide treatment. Wheat growth was reduced by glyphosate. Stress markers (proline and malondialdehyde) were significantly increased by glyphosate showing oxidative damages. Incapacity of wheat to cope with the oxidative stress was evidenced by reduction in thiols and phenolics content, accompanied by slight induction of superoxide dismutase and catalase activities. Enhanced activities of peroxidase, glutathione reductase and glutathione-S-transferase were expected to participate in glyphosate detoxification. SA applied alone had no important effects on measured parameters. SA pretreatment decreased stress markers and caused additional amplification of antioxidant defense systems in glyphosate-treated plants. Growth was partially restored in combine-treated plants due to SA application. SA probably triggered antioxidant defense to cope with the herbicide stress.

Lipid Peroxidation, Proline Content and Soluble Sugars as indicators of Oxidative Stress Tolerance in Some Advanced Durum Wheat Lines (Triticum durum Desf.).

“…It is believed that this increase is due to oxidative damage induced by glyphosate. Furthermore, Sergiev et al (2020) reported that oxidative damage caused by glyphosate application increased significantly the proline content in pea plants; a similar response was also observed in wheat (Shopova et al, 2021). Rapid accumulation of free proline is a response to oxidative stress, with lines G4 and G3 showing a high positive deviation from the average, which are considered the most tolerant under oxidative stress (figure 2).…”

“…The maximum increase in MDA was observed in line G5 (65.8 nmol.g -1 FW), followed by line G3 (52.83 nmol.g -1 FW). The significant increase in MDA content indicates a strong imbalance of the biomembrane lipid peroxidation in the herbicide-treated plants (Shopova et al, 2021). However, we recorded a slight increase of MDA content in genotypes Jupare C 2001, Boutaleb, and Oued el bared with 21.09, 26.32, and 26.96 nmol.g -1 FW respectively, with an average of 35.24; genotypes with a lower level of lipid peroxidation are considered more tolerant to oxidative damage.…”