稀土铽对辣根抗氧化酶的影响

Influence of terbium on horseradish at different concentrations

为了解重稀土对植物的生态毒理学作用,给稀土农用的环境安全问题积累基础实验资料,以辣根为观测材料进行实验,以稀土铽(Tb(Ⅲ))作为探针,研究不同质量比浓度Tb(Ⅲ)对辣根过氧化物酶(HRP)活性,过氧化氢酶(CAT)活性和过氧化氢(H_2O_2)含量的影响。实验结果显示,低质量比的Tb(Ⅲ)对辣根HRP和CAT有激活作用;相反,高质量比,Tb(Ⅲ)对HRP和CAT活性有抑制作用。具体表现为辣根HRP和CAT酶活性先升后降,在Tb(Ⅲ)质量比为1 mg/kg时,HRP酶活性比CK植株增大5.3%。CAT的酶活性比CK植株增加1.23%。H_2O_2含量则是呈先降后升趋势,在Tb(Ⅲ)质量比为3mg/kg时,辣根体内的H_2O_2,含量比CK植株降低11.68%。HRP对Tb(Ⅲ)的反应更为敏感,它可以成为研究稀土毒理的重要生物标志物。

This paper intends to report its investigation over the effects of rare eth terbium （Ⅲ） on horseradish peroxidase （HRP）, catalases （CAT）, and the Hydrogen peroxide （H2O2 ） of potted horseradish. The purpose of this research was to find the ecotoxicological effects of rare earth elements on the plants so as to accumlate basic experimental data for enhancing the environmental safety with their application in agriculture. We adopted nine concentrations of Tb（Ⅲ） solution, with their weight difference of 0 mg/kg, 1 mg/kg, 3 mg/kg, 5 mg/kg, 10 mg/kg, 30 mg/kg, 100 mg/kg, 300 mg/kg, 1 000 mg/kg, and distilled water in the control group and then spayed evenly different Tb （Ⅲ） solutions on the leaves until the drops began to fall. At the same time, the same amount of distilled water was applied to another set of the plant as the control group. The horseradish plant was treated with Tb （Ⅲ） solutions for 48 h, HRP and CAT activities with the content of H2O2 determined. The results of our experiment show that Tb （Ⅲ） at lower concentrations could induce the increase of the activities of HRP and CAT, Th at high concentration, however, would inhibit the activities of HRP and CAT. Compared with CK, 1 mg/kg Tb （Ⅲ） made HRP and CAT activities would increase 5.3 % and 1.23 %, respectively. Nevertheless, the content of H202 tends to decrease first and then increase with the increased Tb （Ⅲ） concentration. 3 mg/kg Tb （Ⅲ） was found to make the H2O2 content decrease by 11.68%. Meanwhile, when the Tb （Ⅲ） concentration was 1 000 mg/kg, the activity of HRP and CAT would turn to be the lowest and the H2O2 content would increase to its highest. Therefore, the change of HRP and CAT activities proves in full conformity with the ＂hormesis effect＂, with the H2O2 content in full agreement with the stated data in the theory. In addition, HRP proves to be more sensitive to Tb （Ⅲ） than CAT and HRP can be taken as a good biological maker of the rare earth toxicity.