Antioxidative defense mechanism against lead-induced phytotoxicity in Fagopyrum kashmirianum

Abstract

The effect of lead (Pb)-induced oxidative stress was investigated in Fagopyrum kashmirianum. The seedlings absorbed the Pb readily by showing time (15 and 30 days) and concentration (0, 100, 200 and 300 μM) dependent effects. Pb caused reduction in both root and shoot lengths but its accumulation was more in roots (22.32 mg g−1 DW) than shoots (8.86 mg g−1 DW) at the highest concentration (300 μM) resulting in translocation factor (TF) < 1 at all concentrations. Thus the uptake and translocation of Pb between roots and shoots showed a positive correlation indicating the plant as root accumulator. Amongst the photosynthetic pigments, chlorophyll content showed a decline while the carotenoid and anthocyanin levels were elevated. The fresh mass and biomass showed a non-significant decrease at both the sampling times. The osmolyte and antioxidative enzymes (SOD, CAT, APX. POD, GR and GST) were positively correlated with Pb treatments except proline and CAT, which showed decline in 30-day-old plants. The alleviation of Pb-stress is an indication for existence of strong detoxification mechanism in F. kashmirianum, which suggest that it could be cultivated in Pb-contaminated soils.