The Bio-Toxcity Of Atrazine On The Stand Wheat Seedings

Atrazine belongs to the widely used herbicides not only in corn field, but also in cereals, lucerne, and sugarcane. Atrazine is a selective uptake before seedlings or postemergence herbicide. Atrazine was mainly absorbed in roots, few in shoots. Herbicide atrazine was rapidly transmitted to the meristen and leaves, inhibiting of photosynthesis, destorying the chlorophyll, hindering carbohydrate synthesis and deoxidation of CO2to make weeds to death. Under the rotation of winter wheat and summer maize, a major double-cropping system in china, our study evaluated the bio-toxicity of residual atrazine to the wheat seedings, including oxidative stress, bioaccumulation and gene damage.In the experiment, the biomass and chlorophyll content of wheat seedings were decreased with the increasing atrazine concentrations. The levels of lipid peroxidation products in wheat seedling were increased by exposured atrazine and the value of TBARS appeared a rising at low concentration and falling at high concentration.With the over accumulation of ROS, the activities of antioxidant enzymes changed. Activities of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) show a general increase at low atrazine concentrations and a decrease at high atrazine levels, while peroxidase (POD) and polyphenol oxidase (PPO) present sustaining increase. The two kinds of detoxifcation enzymes, glutathione S-transferase (GST) and UDP glucose-dependent glucosyltransferase (GTs) show considerable activity under atrazine stress. On the gene express result, the expression of SOD and GST genes were consistent with the activities of corresponding enzymes. Nearly all the five genes present up-regulation at0.2mg kg-1and down-regulation at further concentration. The expression of GST and SOD at0.2mg kg-1and0.4mg kg-1in roots are higher than others.Bioaccumulation in tissues also suggests the toxicity on wheat seedings. The content of bioaccumulation progressively increased with the increasing atrazine concentration. Bioconcentration factors (BCF) and translocation factor (TF) expressed a decrease current, reflecting the harm in translocation mechanism.