Abstract: The growth and main physiological responses of Cuscuta japonica to mixed reagents（ethanol extract of Melia azedarach bark and tusit） were studied. The results showed that the mixed reagent in low concentration had no obvious damage to C. japonica. However,the stem of C. japonica withered up and died after 30 days treatment with high concentration of mixed reagent. Under the high concentration of combination treatment,the content of soluble sugar and malondialdehyde （MDA） of C. japonica increased,whereas the content of soluble protein decreased. Under the high concentration（40 g/L） of ethanol extract of M. azedarach bark treatment,the activity of superoxide dismutase（SOD）,peroxidase（POD） and catalase （CAT） presented a tendency of increased first and then decreased as the concentration of tusite increase in C. japonica. Under the high concentration of tusite（14 mg/L） treatment,the activity of POD and CAT presented a tendency of increased first and then decreased as the concentration of ethanol extract increased. It was indicated that high concentration of mixed reagent which played a role of control was by influencing the metabolism of protein and other biological macromolecules and destroying the balance of protective enzyme system of C. japonica.

Key words: Melia azedarach, ethanol extraction, Cuscuta japonica, physiological indicators, protective enzyme