Cadmium and lead-induced Bacoside-A production, genetic responses, biomass enhancement, and antioxidant defense in Bacopa monnieri (L.) Wettst.: A comparative analysis

Objective & Method: This study investigated the impact of cadmium (Cd) and lead (Pb) on morpho-physiological traits, phytochemical composition and Bacoside-A accumulation in Bacopa monnieri (BM), using metal concentrations optimized from plant samples grown near industrial areas. BM plants were subjected to different concentrations of Cd and Pb. Results: Growth parameters including root length, shoot length and biomass exhibited significant increase in presence of both the heavy metals and maximum increase of upto 30% and 24.3% was obtained at 100 mu M Cd and 50 mu M Pb, respectively. Similarly, substantial improvement was also recorded in physiological properties such that chlorophyll content and antioxidant activity increased 25 % and 35 %, respectively in the presence of Cd. Both metals led to higher Bacoside-A accumulation, such that Cd led to 40 % increase and Pb led to 25 % increase in the content w.r.t. control. The responses under stress conditions were further authenticated using RAPD analysis, which revealed a significant genotoxic effect showing stress-responsive genetic variations that can be critical for understanding plant adaption mechanisms. Conclusion: This study affirmed that moderate levels of heavy metals (50 mu M -100 mu M) could stimulate growth and secondary metabolite production in BM. Therefore, BM should be considered for phytoremediation in industrial areas, leveraging its ability to thrive under heavy metal stress and accumulate beneficial secondary metabolites for pharmaceutical industry.