The antioxidant defense responses of Hordeum vulgare L. to polycyclic aromatic hydrocarbons and their derivatives in biochar-amended soil

The recent studies indicated that the biochar (BC) may be a source of polycyclic aromatic hydrocarbons (PAHs) as well as their oxygen, nitrogen, or sulfur-containing derivatives that are considered as more toxic pollutants than their parent compounds. Here, the assessment of the impact of various biochars addition (1% wt.) to soil on barley Hordeum vulgare L. growth was presented. The concentrations of bioavailable PAHs and their derivatives in biochar were determined. PAHs increased reactive oxygen species generation resulting in oxidative stress in organisms. In this study, the response of soil-grown plants was examined in terms of the activity of the antioxidative enzymes (superoxide dismutase, catalase, peroxidase), lipid peroxidation, and the expression of genes related to oxidative stress. The results indicate that despite low content of a bioavailable fraction of parent compounds and their derivatives (up to 4.45 +/- 0.24 ng gbiocharxe213; 1 and 0.83 +/- 0.03 ng L-1, respectively) the biochemical response of plant was present, the activity of superoxide dismutase increased up to 2 times, but the activity of the other enzymes was lowered. The transcript level values support the studies on enzymatic activity. The presence of PAHs and their derivatives induced oxidative stress slightly but the plant was able to mitigate it.