Effect of Varying Concentrations of Lead (Pb) on the Growth and Protein Profile of Ipomoea aquatica Forssk.

Abstract

The effect of varying concentrations of lead (Pb) on the growth and protein profile of Ipomoea aquatica Forssk. was investigated. Different concentrations of lead (1, 10 and 20 ppm lead) were incorporated in the hydroponics solution for 21 days. Root length, root-shoot ratio, leaf area, dry weight were found to have no significant difference at a=0.05. Whereas, shoot length, leaf number, fresh weight and hypocotyl growth were found to be significant at a=0.05. There was no significant difference in the chlorophyll content and protein content of I. aquatica Forssk. Tolerance index decreased significantly with increasing lead concentration. A positive correlation between the lead concentration and the lead accumulation per mg/kg dry weight was observed. SDS-PAGE analysis detected 7 bands in the control, 11 bands in Ippm lead treatment, 10 bands in lOppm lead treatment and 12 bands in 20 ppm lead treatment. Four bands with molecular weights of 104, 43, 40, and 25 kDa were present in only in the 20 ppm lead treatment. Since Ipomoea aquatica Forssk. does not have specific phytotoxic symptoms when subjected to lead, careful monitoring of the major freshwater systems must be done in order to prevent lead toxicity to humans by ingesting lead contaminated freshwater macrophyte such as I. aquatica.