Pongamia pinnata (L.) Pierre tree seedlings offer a model species for arsenic phytoremediation

Hydroponic experiments were conducted to investigate the effect of different concentrations of arsenic (As) on seedlings of Pongamia pinnata (L.). Results revealed that P. pinnata successfully tolerated As up to 0.2-1.0 mM and did not show significant reduction in growth and chlorophyll contents. However, the values of these parameters significantly reduced at 1.5 mM of As exposure. Further, P. pinnata accumulated As about 1129-3322 mg kg− 1 dry weight in roots, and 345-3662 mg kg− 1 dry weight in shoots, respectively when exposed to 0.2-1.5 mM As. Arsenic exposure at 0.2-1.5 mM significantly enhanced oxidative stress markers [superoxide radical (SOR), hydrogen peroxide (H2O2) and malondialdehyde (MDA)] contents, and activities of antioxidants [ascorbate peroxidase (APX) and catalase (CAT)] and nutrient accumulation. Increase in antioxidants and nutrient accumulation might have protected plants from As exposure. Additionally, bioaccumulation and translocation factors were > 1 which also confirmed that test plant has greater ability to accumulate and detoxify greater amount of As.