Effect of antioxidants on membrane lipid oxidative damage during reoxygenation and chemical oxidative stress in wheat and rice seedlings

The role of antioxidants (trolox, ascorbate, and reduced glutathione) and the plasma membrane NAD(P)H oxidase inhibitor diphenylene iodonium in modulating lipid oxidative damage under oxidative stress caused by anoxia / reaeration or prooxidants was assessed. Plants were kept for 24 h in the analyzed antioxidant / DPI and then exposed to 24 h anoxia / 24 h reaeration or a prooxidant (H2O2 or menadione). The intensity of lipid peroxidation (LP) was assessed by measuring the content of thiobarbiturate (TBA)-reactive products. The effects of anoxia / reaeration and prooxidant treatment resulted in a comparable increase in LP in both plants, with a slight predominance in wheat. Pretreatment with antioxidants contributed to LP reduction. The positive effect was more pronounced in the roots, probably due to the studied substances administration through the roots. All antioxidants reduced LP intensity to the control level in rice roots. Trolox was identified as the most effective antioxidant. DPI lowered LP only in rice, which may indicate the importance of the plasma membrane in signaling and the development of oxidative damage during anoxia and reaeration. The highest suppression of LP by antioxidants was observed in rice plants, probably due to a more effective antioxidant system.