氯苯甲酸植物毒性实验中抗氧化酶变化的量化研究

为研究氯苯甲酸(CBA)的植物毒性,评估生物化学参数能否作为CBA植物毒性的指示因子,采用对CBA敏感的小白菜种子和大白菜种子进行暴露实验,在根伸长抑制率为10%～50%的质量浓度范围内,研究了CBA剂量-抗氧化酶活性的关系.结果表明:随着CBA质量浓度的升高,超氧化物歧化酶(SOD)活性总体上呈逐渐上升至峰值然后下降趋势,过氧化物酶(POD)活性逐渐降低,过氧化氢酶(CAT)活性与SOD活性近似,呈先升后降趋势,但幅度大于SOD活性.对CBA剂量-酶活性抑制率进行了回归分析,对拟合效果进行了显著性检验(P<0.05),并求出相应的半效应浓度(EC50),实验材料的SOD和CAT活性的EC50均在实验区间之外,POD活性的EC50则在实验区间之内,表明在实验区间内,SOD和CAT活性不敏感,POD活性为有效指标 

Quantity Relationship of Antioxidant Enzyme Activity in the Toxicological Vegetation Test of Chlorobenzoate Acids

To investigate the phytotoxicity of chlorobenzoate (CBA) and to evaluate biochemical endpoints’ suitability and sensibility, two terrestrial plant species in same category, Chinese Cabbage (Brassica chinensis) seeds and Chinese White Cabbage (Brassica pekinensis) seeds, were exposed to different mass concentrations of CBA in a germination test and the relationship of CBA dose-antioxidase activity was studied in the 10%～50% of elongation inhibition range. The results indicated: with the mass concentration of CBA rising, the superoxide dismutase (SOD) activity firstly raised and reached summit, then decreased, the perioxidase (POD) activity gradually decreased, and the catalase (CAT) activity had a similar result with SOD activity, however the degree of variance was bigger than that of SOD activity. The regression was analyzed for CBA dose-inhibition rate of antioxidant enzyme and the significant test (F-statistic) of plotting equation (P<0.05)was also done, therefore the half effect concentration (EC_ 50 ) was got by the plotting equation. With respect to the fitting equation and biochemical knowledge, the EC_ 50 of SOD and CAT were out of the experimental range; however POD’s was in the range of it. This suggested that the inhibition degree of SOD and CAT activity was an invalid indicator; however the inhibition degree of POD activity was a valid indicator.