Evaluation of Free Radical Scavenging Activities Against Multiple Heavy Metals Stress in Avicennia marina (Forsk.) and Rhizophora mucronata Lamk
The tolerance mechanism of mangrove species (Avicennia marina (Forsk.) and Rhizophora mucronataLamk) was studied by inducing multiple heavy metal stress in roots and leaves of the plants. Mangrove seedlings weretreated with different concentrations of heavy metal solution (Cr, Cd, Pb and Hg) for a period of 2 months. Scavengingantioxidant enzymes like Polyphenol Oxidase (PPO), Glutathione-S-transferase (GSTs) and Guaiacol Peroxidase(POD) were analyzed in both species after appropriate intervals of 15 days. Results revealed that activities of theseantioxidative enzymes were altered due to multiple heavy metals exposure in both mangrove species, whereas leavesexhibited the higher values as compared to the roots. In the leaves of both mangrove plants GSTs exhibited anincreased trend throughout the investigated period whereas, PPO activity initially showed an increasing trend, butgradually decreased with the passage of time in response to heavy metal stress. Furthermore, an increased level ofantioxidants was also observed in A. marina than R. mucronata which proves that the former is a strong candidate forheavy metals phyto-remediation with its viable survival strategies.