Effect of lead on plant growth, lead accumulation and biochemical changes of Pistia stratiotes L.
By: Monica Mishra, Ashirbad Mohapatra, Kunja Bihari Satapathy
Key Words: Lead, Phytoremediation, Pistia stratiotes
Int. J. Biosci. 9(6), 66-78, December 2016.
Aquatic macrophytes are well known accumulators for heavy metals in contaminated water bodies. The objective of this study was to evaluate the effect of lead nitrate on the growth, accumulation and biochemical changes of Pistia stratiotes L. Plants were cultured in Hoagland’s medium which was exposed to different concentrations (10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 mg/l) of lead nitrate solutions. The toxicity symptoms of Pb on P. stratiotes showed chlorosis on leaves followed by significant decrease in the relative growth, biomass productivity, chlorophyll content, protein and carbohydrate content with increased concentrations. But with the increase in Pb concentration (20, 40, 60, 80, 100 ppm) an increased proline content (0.516±0.01, 0.739±0.01, 0.956±0.02, 1.434±0.03, 1.844±0.05 µg/g fresh weight) was observed in Pistia stratiotes irrespective of the period of treatment. Increased concentrations of Pb (100 mg/l) in the growth medium enhanced the bio-concentration factor of P. stratiotes up to an optimum value of 1239.56, while the relative growth of plants significantly decreased (0.79 g). These responses indicate the potential of Pistia stratiotes L. not only as a lead scavenger but also a suitable tool for phytoremediation in the aquatic environment.