Abstract
The present study investigated the influence of inorganic amendments viz., SDS (sodium dodecyl sulphate) and ethylenediaminetetraacetic acid (EDTA) in enhancing metal tolerance in plants. Seedlings of an important ornamental plant, Dahlia variabilis Cav. were grown under cadmium (Cd) and lead (Pb) stress. 30days old seedlings were transferred to pots containing sterilized sand and supplemented with Hoagland's medium. After 15 days of transplanting, four treatments (0, 10, 25, and 100 mg kg(-1)) of Cd and four treatments of Pb (0, 100, 500 and 5000 mg kg(-1)) were used with or without application of 2.0 mM SDS and 2.5 mM EDTA, separately and in combination. Seedlings were further grown for 60 days in culture media. Results revealed that both Cd and Pb significantly reduced plant growth, pigment content, and relative water content. Antioxidant enzymes viz., superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) along with protein and total soluble sugar contents showed a declining trend with an increase in Cd and Pb concentrations applied. The Cd and Pb treatment enhanced the production rate of reactive oxygen species (ROS) as depicted by the increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) production in leaf. Inorganic amendments viz., EDTA+SDS applied either alone or in combination significantly alleviated Cd and Pb-induced toxic effects. However, a combination of EDTA+SDS showed significant results than used separately. These results revealed that the application of inorganic amendments in combination can enhance the phytoextraction capacity of the species studied. However, the effects of various amendments vary with the nature of the inorganic compound. The study suggests that the application of EDTA and SDS could be a useful strategy for enhancing the phytoextraction capability of Dahlia variabilis to remove Cd and Pb from contaminated soils.