Evaluation of Antioxidant Defense and Phytoremediation Efficacy of a Submerged Aquatic Macrophyte Hydrilla verticillata(L.f.) Royle under Lead Stress

摘要

Lead-induced antioxidative response of a submerged aquatic macrophyte Hydrilla verticillata was investigated under laboratory condition. The plant was collected from a fresh water pond and bioassayed with varying concentrations of Pb for fifteen days. The activities of enzymatic antioxidants such as Catalase, Superoxide dismutase, Monodehydro ascorbate reductase, Glutathione reductase, Ascorbate peroxidase, Polyphenol oxidase and Phenyl alanine ammonia lyase and non-enzymatic antioxidants (carotenoid, flavonoid, proline, phenol and ascorbate) were analyzed. Phytoremediation efficacy of the macrophyte for lead was evaluated and supported with the quantification of Bioconcentration Factor (BCF). Data were statistically analyzed and levels of significance were recorded. SOD activity, phenol (P-value＜0.0001) and proline (P-value=0.0009) accumulation were extremely significant in treated plants as compared to control. APX, GR, PAL, CAT, MDHAR and PPO activity were significant in metal treated plants than control. Very significant amounts of carotenoid and flavonoid were encountered while ascorbate content remained non-significant. Enzymatic and non-enzymatic antioxidants were positively correlated with biosorption of Pb and were significant. Significant lead accumulation suggested that Hydrilla verticillata was a promising candidate for phytoremediation of Pb. The present study helped assess the enzymatic and non-enzymatic antioxidant defense in Hydrilla verticillata suggesting the enhanced activation of SOD and increased accumulation of phenol and proline as a biomarker of Pb stress and tolerance.