运用蚕豆幼苗叶片生物标志物评价铅污染土壤

Evaluation of Soil Lead Contamination by Biomarkers in Leaves of Vicia faba L. Seedlings

以蚕豆(Vicia faba L.)幼苗为供试植物,通过室外盆栽实验研究了暴露5周后的蚕豆幼苗叶片应激蛋白(HSP70和HSP60)等相关生物指标对土壤铅胁迫的响应.结果表明,随着外源铅的增加,叶片总铅含量、超氧阴离子自由基(O2.-)和膜脂质过氧化产物都在不同程度上得到增加.相关性分析表明,O2.-与膜脂质过氧化产物(r=0.973,p<0.01)之间存在显著的相关性.超氧物歧化酶、过氧化物酶、过氧化氢酶和抗坏血酸过氧化物酶活力均被相应的诱导.HSP70和HSP60对铅污染的响应比上述其它生物指标更加敏感.可见,土壤铅进入叶片后,可能通过O2.-的作用诱导了膜脂质过氧化,而4种抗氧化酶活力的提高缓解了活性氧的氧化损伤.HSP70和HSP60可作为土壤铅污染早期诊断的潜在的生物标志物,同时还应该考虑铅的暴露剂量并综合利用其它生物指标.

Stress proteins （HSP70 and HSP60） and other related biological parameters were investigated in leaves of Vicia faba L. seedlings subjected to soil lead stress. The seedlings were cultivated outdoors in pots for five weeks. Results showed that total lead content, superoxide radical （ O2^- ） and lipid peroxidation productions in the leaves increased with the increase of extraneous lead in soils. Significant correlation was found between the O2^- and lipid peroxidation productions （ r = 0.973, p 〈 0.01 ）. Activities of superoxide dismutase （SOD）, guaiacol peroxidase （POD）, catalase （CAT） and ascorbate peroxidase （APX） were activated. Moreover, HSP70 and HSP60 increased more sensitively than the other parameters in response to lead stress. This indicates lead might cause lipid peroxidation in the leaves by mediation of O2^- . The activated antioxidative enzymes alleviated the stress and damage of reactive oxygen species. HSP70 and HSP60 are potential biomarkers for early warning of lead-contaminated soils. Additionally, concentrations of soil lead and related biological parameters should be combined.