Differential amelioration of cadmium toxicity by sodium nitroprusside and citric acid in Brassica juncea (L.) Czern and Coss

Abstract

Cadmium (Cd) is a highly toxic heavy metal for the living world. Cd toxicity leads to plants growth retardation; decrease in chlorophyll content, photosynthetic efficiency and food grain quality-quantity due to increased oxidative damage (quantitated in terms of malondialdehyde, MDA content and hydrogen peroxide H 2 O 2 levels) and suppresses the antioxidant defense systems. Through this present investigation, we tried to have an insight into the differential responses due to sodium nitoprusside (SNP, an important source of nitric oxide) and citric acid (CA) in Cd treated mustard seedlings in terms of metal accumulation and stress tolerance in Brassica juncea. Mustard seedlings when treated with Cd in combination SNP and CA in hydroponic culture for three days led to recovery of growth and biomass, suppression of oxidative damage and enhancement in the activities of antioxidant enzymes. The results clearly depict that SNP and CA plays crucial part in alleviation of Cd toxicity in mustard seedlings. Further among the two agents used for amelioration of Cd toxicity, SNP was found to be more efficient than CA. Besides we also observed that SNP reduces the translocation of Cd in above ground portion of mustard plant which might also lead to reduction of Cd accumulation in the edible parts of the plant. • Sodium nitroprusside treatment leads to lesser accumulation of Cd in plants. • Sodium nitroprusside and citric acid both improves photosynthetic efficiency. • Sodium nitroprusside and citric acid enhances the antioxidant enzymatic activities. • Sodium nitroprusside rendered better tolerance to Cd toxicity than citric acid.