[Effects of herbicide acetochlor on physiological mechanisms in wheat and biomarkers identification]

Changes of the activity of antioxidant enzymes including peroxidases (POD) and superoxide dismutases (SOD) and the contents of chlorophyll (CHL), malondialdehyde (MDA), and soluble proteins (SP) in wheat (Triticum aestivum L.) under the stress of acetochlor in soil were examined. The increased MDA level detected in the leaves of wheat after 1 day exposure of acetochlor indicated the presence of poisoning AOS. However, the difference of MDA levels in leaves of different concentrations of acetochlor decreased with the prolonged exposure. The data of POD could suggest that the plant had the capacity to counteract the oxidative stress caused by lower concentration of acetochlor, but the capacity would be lost with exposure time. It is indicated that the increase of POD activity in the leaves may be caused by H2O2 produced from sources other than SOD. The activity of POD and contents of MDA could not be considered as biomarkers of stress by acetochlor in soil. While the activity of SOD could be considered as biomarkers of stress by acetochlor in soil need farther research. But the contents of CHL and SP could be considered as biomarkers of stress by acetochlor in soil and there are dose-response relationships between the SP content in leaves and the concentration of acetochlor in soil.