In view of their potential bioaccumulation of heavy metals, Ceratophyllum demersum and
Myriophyllum spicatum was studied under hydroponic cultures enriched by different Pb
concentrations (25, 50, 75 mg/l) for 1–7 days. Both species exerted remarkable capabilities
to concentrate Pb in their tissues as compared to control. The highest accumulation value of
Pb (164.26 mg/g.dw) was recorded in C. demersum and the most of metal (91.72 mg/g dw)
accumulated after 1 d. Significant reduction in photosynthetic pigments and appearance of
morphological symptoms such as chlorosis and fragmentation of leaves were evident after
7d at 75 mg/l. The activity of POX and APX, carotenoids and proline showed induction at
lower concentration and duration followed by decline. Major re-shuffle in protein patterns
appeared as a tolerant mechanism, which both species developed under Pb toxicity. Results
suggest that both species responded positively to Pb concentration and accumulated high
amount of metal. Due to metal accumulation coupled with detoxification potential, both
species appear to have potential for use as phytoremediators and the developed responses
can be used as reliable biomarkers for Pb water pollution.