Antioxidative and Biochemical Responses in Dalbergia sissoo Roxb. Seedlings Growing Under Cobalt and Lead Stress

Abstract

Dalbergia sissoo Roxb. is one of the most important timber species of India. It is used for high quality furniture, cabinets making and has pesticidal property. It is commonly planted tree species in urban and suburban areas, roadsides and industrial areas where the soil may be polluted with heavy metals such as Co or Pb. Lead (Pb) and Cobalt (Co) are one of the non essential and toxic heavy metals which can cause oxidative stress in plants. The concentrations of these heavy metals in the environment are currently increasing, due mainly to anthropogenic activities. The effect of these heavy metals on biochemical parameters and antioxidant activity were studied in leaves of Dalbergia sissoo Roxb. grown under control laboratory conditions in pot culture and four levels of heavy metal stress (10, 20, 30 and 40ppm Pb2+, Co2+). Six months exposure of Dalbergia sissoo Roxb. plantlets to different concentration of Co or Pb in normal soil conditions elicited an antioxidative response, measured in terms of ascorbic acid, proline accumulation and biochemical responses in terms of protein and free amino acids. The results indicate that the proline, ascorbic acid contents increased with increase in Co and Pb amount in soil whereas the protein and total chlorophyll contents showed opposite trend.