Lead Tolerance and its Accumulation by a Tree Legume: Dalbergia sissoo DC

Dalbergia sissoo DC, a leguminous tropical timber tree has been investigated against the Pb toxicity; under the Pb-stress, plant's morphology, biochemical parameters and genomic template stability (GTS) screened in vitro. At the optimum Pb tolerance level (150mgL(-1)), plant's defense mechanismsuperoxide dismutase, catalase, ascorbate peroxidases and proline could trigger to achieve optimum vegetative growth with minimum fluctuations of the GTS. Further, D. sissoo roots could accumulate 2399.8 +/- 16mgkg(-1) Pb. Scanning electron microscopy and energy dispersive X-ray spectrometer analysis also revealed the deposition of Pb in root tissues. In a 1year pot experiment with Pb-contaminated soil, the plants exhibited normal growth, and Pb accumulation significantly enhanced by the amalgamation of citric acid in the soil. Thus, the tree may prove as a potential candidate for Pb phytostabilization.