| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4420089 | Ecotoxicology and Environmental Safety | 2014 | 9 Pages |
•S. grandiflora root tissue accumulated higher Pb content.•The level of MDA and photosynthetic pigment contents enhanced by Pb toxicity.•Antioxidative defense enzymes were effectively activated by Pb induced stress.•Pb heavy metal toxicity affects genomic template stability.•Plants had effective detoxification mechanism for hyperaccumulation of heavy metal ions.
The present study was aimed at evaluating phytotoxicity of various concentrations of lead nitrate (0, 100, 200, 400, 600, 800 and 1000 mg L−1) in Sesbania grandiflora. The seedling growth was significantly affected (46%) at 1000 mg L−1 lead (Pb) treatment. Accumulation of Pb content was high in root (118 mg g−1 dry weight) than in shoot (23 mg g−1 dry weight). The level of photosynthetic pigment contents was gradually increased with increasing concentrations of Pb. Malondialdehyde (MDA) content increased in both the leaves as well as roots at 600 mg L−1 Pb treatment and decreased at higher concentrations. The activity of antioxidative enzymes such as superoxide dismutase and peroxidase were positively correlated with Pb treatment while catalase and ascorbate peroxidase activities increased up to 600 mg L−1 Pb treatment and then slightly decreased at higher concentrations. Isozyme banding pattern revealed the appearance of additional isoforms of superoxide dismutase and peroxidase in Pb treated leaf tissues. Isozyme band intensity was more consistent with the respective changes in antioxidative enzyme activities. Random amplified polymorphic DNA results indicated that genomic template stability (GTS) was significantly affected based on Pb concentrations. The present results suggest that higher concentrations of Pb enhanced the oxidative damage by over production of ROS in S. grandiflora that had potential tolerance mechanism to Pb as evidenced by increased level of photosynthetic pigments, MDA content, and the level of antioxidative enzymes. Retention of high levels of Pb in root indicated that S. grandiflora has potential for phytoextracting heavy metals by rhizofiltration.
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