Phyto-exclusion of Pb and Cd by different genotypes of Andrographis paniculata (Burm. F.) nees: A novel approach for safe cultivation

Pb and Cd are ubiquitous heavy metals (HMs) in the environment and their accumulation in medicinal herbs poses a serious threat due to health hazards. The genetic selection of high-yielding and low Pb and Cd accumulating genotypes known as phtyoexclusion is a cost-effective and promising phytotechnology. In the present study, phtyoexclusion method was used for the selection of low Pb and Cd accumulating genotypes of Andrographis paniculata (Burm.F.) Nees with minimum alteration in their pharmacological important constituents in three application rates of Pb and Cd. The performance of genotypes of A. paniculata was evaluated by uptake and translocation of Pb and Cd, biomass yield, shoot-to-root ratio, metabolite content, oxidative enzymes, and mineral content for their safe production and commercial viability. The bio-concentration factor (BCF) and translocation factor (TF) of Pb among the genotypes ranged from 0.09-3.6 and 0.006-0.045, respectively. However, variations in BCF and TF of Cd were 0.05-3.36 and 0.001-0.150 respectively. The differential expression of the metal accumulation in genotypes of A. paniculata was majorly associated with ionomics and biomass. Four genotypes of A. paniculata were screened out and were divided in the three categories. One, genotypes that accumulated Pb and Cd below the prescribed limits with high productivity and tolerance could be used for safer herb production. In the second category, genotypes having high accumulation in roots and low translocation could be used for phytostabilization of the soil. The above-ground material of the plant can be used for the extraction of pure constituents. The third one is genotypes with high accumulators and low productivity.