Assessment of antioxidant system and enzyme/nonenzyme regulation related to ascorbate-glutathione cycle in ferulic acid-treated Triticum aestivum L. roots under boron toxicity

Abstract

Ferulic acid (FA; 3-methoxy-4-hydroxycinnamic acid) can eliminate stress-induced damage because of its ability to induceantioxidant activity under stress. The aim of this study was to identify the effects of FA on water status, antioxidant system, and lipidperoxidation in wheat (Triticum aestivum L.) roots exposed to boron (B) stress. Plants were grown in hydroponic culture containingthe combination or alone form of 25–75 μM FA and 4–8 mM B. Stress significantly decreased growth (RGR), water content (RWC),proline content (Pro), and osmotic potential (YP). However, FA alleviated the decrease in RGR, RWC, and Pro content. Compared tothe control groups, stress decreased the activities of superoxide dismutase (SOD), peroxidase (POX), catalase, and ascorbate peroxidase(APX), but an increase was only observed in glutathione reductase (GR) activity. Hydrogen peroxide (H2O2) content accumulated withB stress. Besides, a notable decrease was observed in the scavenging activity of hydroxyl radical (OH•); thus, wheat roots had high lipidperoxidation (thiobarbituric acid reactive substance content). In response to stress, FA triggered the activities of SOD, POX, and APX.Moreover, when FA was made present in stressed wheat roots, we observed the enhanced activities of dehydroascorbate reductase,and monodehydroascorbate reductase and dehydroascorbate contents which are related to ascorbate-glutathione cycle, so FA couldmaintain ascorbate (AsA) regeneration. However, when wheat roots were treated with stress, FA did not induce the regeneration ofglutathione because of decline in GR activity. Due to successful elimination of H2O2 content, the exogenous application of FA alleviatedB-induced lipid peroxidation in wheat. Consequently, FA eliminated the damage induced by B stress via the increased POX and theenzymes related to Asada-Halliwell pathway (AsA-GSH cycle) in wheat roots.