Study On Toxico Effects On Lemna Minor In The Water With Butachlor, Thiamethoxam And Azoxystrobin

China is a large agricultural country and has large population from ancient times to the present. The throughput and application amount of agricultural chemicals at the forefront of the world. Agricultural chemicals are inevitably spread to the air during its production and using, and by rainfall or other ways get into the water or soil, then pollute them. Reseach the impact of agricultural chemicals on the aquatic ecological environment has important significance in ecotoxicological studies.This article use Lemna minor for test material, study the growth of Lemna minor with Butachlor, Thiamethoxam and Azoxystrobin, according to the study of chlorophyll, CAT, SOD, and MDA, prod into the injury mechanism, provide a scientific basis for fair use of these three kinds of agricultural chemicals. The results show that:1. Butachlor, Thiamethoxam and Azoxystrobin can restrain the growth rate of the Lemna minor. The function of Butachlor is the strongest, and Thiamethoxam is the feeblest. Butachlor can also damage the leaves. These three kind of agricultural chemicals can lead to the content of chlorophyll decrease. The higher the concentration, the lower the content of chlorophyll.2. Study the CAT, SOD, and MDA, these physiological indexes can show the reacts in contaminated. These physiological indexes have time effect. Different physiological index have different response rate.3. In the combined action of these three kind of agricultural chemicals, Butachlor have the main function. These three kind of agricultural chemicals have no synergistic reaction and haven’t antagonistic effect, either.