Preliminary screening of growth performance, biochemical profiling and accumulation capacity of Senna tora and S. uniflora to lead stress

Abstract

Lead is a non-essential element that has a detrimental effect on plant growth and metabolism when accumulated in higher quantities. In the present study, we investigate effect of lead on Senna tora (L.) Roxb. and Senna uniflora (Mill.) H.S. Irwin and Barneby, those grow dominantly on banks water bodies in the Kolhapur district, Maharashtra, India. We assessed the relative effects of varying lead concentrations on the growth of seedlings, biochemicals and accumulation capacity of both species. In both species, the seedling growth was reduced in response to lead treatment at concentrations 5, 10, 20 and 40 mg kg-1 of soil and the germination of seed, root and shoot growth, fresh and dry biomass were highly diminished at 40 mg of lead kg-1 of soil. The growth parameters decreased with the increased accumulation of lead (i.e., 0.073, 0.110, 0.149 and 0.170 mg g-1 and 0.122, 0.169, 0.212 and 0.429 mg g-1 at 5, 10, 20 and 40 mg kg-1 of soil) in S. tora and S. uniflora, respectively. Decline in the content of chlorophyll, reducing sugar, total sugar and protein was a common feature while, proline content increased at 5, 10, 20 and 40 mg of lead kg-1 of soil for S. tora and S. uniflora, respectively. In both plant species, an increase in lead concentration resulted in a decrease in the bioconcentration factor and tolerance index. The growth performance and biochemicals were impaired due to different concentrations of lead.