Influence of tannery sludge on oil yield, metal uptake and antioxidant activities of Ocimum basilicum L. grown in two different soils

•POD was better intrinsic defensive tool than SOD and CAT.•Metal uptake by Ocimum basilicum depends upon soil properties and soil type.•Oil content increased at 50:50 ratio of sludge and soil of both sets.

Application of sludge to soil for increasing crop productivity has become an alternative to chemical fertilizers in many countries. The present study aimed at investigating the effect of tannery sludge (TS) under two soil types viz coarse soil (Set A) and fine soil (Set B) on oil yield, metal uptake and antioxidant activity of Ocimum basilicum. Experimental data showed that increased biomass and oil yield were observed at 50:50 ratio of sludge and soil of both Sets. Cation exchange capacity (CEC) played a major role in metal uptake which was showed by step wise regression model. Superoxide dismutase (SOD) and catalase (CAT) activity went down in 100% TS, however peroxidase (POD), malondialdehyde (MDA) and proline activity was maximum in 100% TS. POD act as a better intrinsic defense tool to resist the heavy metals present in TS. Principal component analysis (PCA) showed that soil properties should be taken into consideration for predicting heavy metal accumulation in plant.

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