Physiological and Antioxidant Responses in Wheat (Triticum aestivum) to HHCB in Soil

Seedlings of wheat (Triticum aestivum) were exposed in soil to the polycyclic musk chemical, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2-benzopyran (HHCB) for 21 days, to evaluate its effect upon chlorophyll (CHL), lipid peroxidation and the antioxidant system. The content of CHL in leaves was inhibited significantly after 14- and 21-days exposures, whereas it was significantly induced by a low level of HHCB after a 7-days exposure. The content of malondialdehyde (MDA) in wheat leaves increased with an increase in the concentration of HHCB in soil, indicating that oxidative stress could be induced by HHCB. Moreover, HHCB exposure induced significant antioxidant responses in wheat. The activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in wheat leaves were induced by HHCB after 14 and 21 days of exposure. However, the changing trend of the antioxidant enzymes in wheat roots was different from that in leaves. The results suggested that the assayed parameters of T. aestivum could be used as responsive biomarkers for oxidative stress in the soil environment.