铅污染对芦荟抗氧化活性影响的研究

Study on effects of lead on the antioxidant activities of Aloe vera

采用盆栽试验,对芦荟在不同浓度Pb胁迫下抗氧化酶系统的变化进行了研究。用流动注射化学发光分析法,以亚甲基蓝-Fenton体系、鲁米诺-邻苯三酚体系分别测定盆栽芦荟体内抗氧化酶清除·OH和清除O2-·的能力,进而评价铅污染对芦荟生物活性的影响。结果表明,在相对低浓度铅污染水平下,芦荟提取酶的活性均比无污染时的对照值有所升高,并与芦荟体内铅含量成正相关;而在相对较高浓度铅污染下,提取酶的活性均比对照值有所下降,与芦荟体内铅含量成负相关。说明在低浓度铅毒害作用下,芦荟体内抗氧化酶系统对重金属胁迫的生理的响应使其活性有所上升;高浓度铅毒害使芦荟自身的保护机制遭到破坏,体内抗氧化酶系统也受到一定损害,使其活性值降低。

The variation of the antioxidant enzyme system of Aloe vera under the stress of different Pb concentrations was studied using pot experiments. The scavenging abilities of the potted Aloe vera to ·OH and O2^-·were determined by flow injection chemiluminescence method using methylene blue- Fenton system and 1,2,3-trihydroxybenzene system. The effects of lead pollution on the enzymatic activity of Aloe vera were evaluated. The results showed that at a relatively low lead pollution level, the enzymatic activity of polluted Aloe vera was higher than that of the un-polluted, and increased with the increase of lead concentration in Aloe vera body; while at a relatively higher lead pollution level, the enzymatic activity of polluted Aloe vera was lower than that of the un-polluted, and the ac- tivity decreased with the increase of lead concentration in Aloe vera body. These indicated that at a low pollution level the physiological response of Aloe vera antioxidant enzyme system to heavy metal stress resulted in the rise of enzymatic activity of Aloe vera ; while at a high pollution level, the self protection system of Aloe vera is damaged, which in turn led to the damage of antioxidant enzyme system, and then results in the decrease of the enzymatic activity.