以萘、菲和芘为供试多环芳烃(PAHs),采用水培试验方法,研究了PAHs污染下黑麦草(Lolium multiflorum Lam)体内过氧化物酶(POD)和多酚氧化酶(PPO)的响应。结果表明,菲处理浓度为0-1.8mg·L^-1,144h后,黑麦草根和茎叶中POD、PPO活性均随菲处理浓度的增加先升高后降低;表明低菲污染可激发供试植物酶活性,高污染则对酶活有抑制作用。萘、菲或芘处理后,植物不同部位酶的表达存在差异,黑麦草根中POD活性整体上高于茎叶,而茎叶中PPO活性则高于根。黑麦草根或茎叶中POD、PPO对供试3种PAHs的敏感性响应顺序为萘〈菲〈芘,与污染物自身毒性强弱顺序一致。
Understanding the relation of organic contaminants and enzyme in plants is important for risk assessment on polluted sites. However, there is still limited information on the impacts of polycyclic aromatic hydrocarbons (PAHs)on enzyme of plants. In this paper, the activities of POD (peroxidase)and PPO (phenol oxidase)in ryegrass were evaluated under the effects of phenanthrene, pyrene and naphthalene as representatives of PAHs. Results showed that, the activities of tested enzymes firstly increased and then decreased with increasing the concentrations of phenanthrene from 0 to 1.8 mg·L^-1. Enzymes differed greatly in different parts of plants. For the same treatments with phenanthrene, pyrene or naphthalene, the POD in plant roots was generally higher than that in shoots. In contrast, the PPO in shoots was higher than that in roots. Additionally, the response sensitivities of the tested two enzymes in plants against the tested PAHs increased following the order of naphthalene〈 phenanthrene 〈pyrene, which is the same order as the toxicity of the three PAHs.