P-372 - Salicylic acid improves the performance of the enzymatic antioxidant system of barley exposed to glyphosate

Abstract

Glyphosate (Gly) is the most used herbicide worldwide and, despite it can be metabolized by microorganisms, it can negatively affect non-target plants. Thus, there is a need to find new strategies that enhance plant tolerance to Gly, allowing a more advantageous, yet not safer, use of this herbicide. Salicylic acid (SA) is a hormone-like substance, able to enhance the efficiency of the antioxidant (AOX) system in plants and their tolerance to oxidative stress (OS). Thereby, this study aimed to unveil the effects of SA (100 μM) on the oxidative status of Hordeum vulgare L. in response to Gly (30 mg kg-1). After 14 days of growth, foliar and root levels of H2O2 were increased after Gly exposure, but manifested a clear decrease tendency upon co-exposure with SA. Regarding O2•- production, its content was only increased in roots. The activity evaluation of the main AOX enzymes (superoxide dismutase – SOD; catalase – CAT; ascorbate peroxidase – APX) revealed the activation of several defense mechanisms against Gly. Generally, all studied enzymes were positively affected by Gly in both organs. However, upon SA co-treatment, the response of the plant AOX system was even more notorious, suggesting a positive role of this substance against Gly-induced OS.