The present study investigates the effect of long and short term Cd stress in chickpea plants and evaluates the protective effect of
exogenous nitric oxide (NO) supplementation using sodium nitroprusside (SNP). Cadmium treatments were given before sowing
(long term stress) and thirty days after germination (short term stress). Sodium nitroprusside was given as foliar spray 30 days
after germination to both long and short term Cd treated plants. Cadmium adversely affected the membranes as was evident from
increased electrolyte leakage and lipid peroxidation levels. Sodium nitroprusside treatments decreased ion leakage and lipid peroxidation
levels significantly. Short term Cd stress resulted in a higher induction of the catalase, peroxidase, ascorbate peroxidase, glutathione
reductase and superoxide dismutase as compared to long term Cd stress. Nitric oxide showed its positive effect by further increasing
the activities of antioxidant enzymes. Cadmium stress also altered the level of antioxidant metabolites by reducing the ascorbate redox
ratio (ASC/DHA) and glutathione redox ratio (GSH/GSSG). Sodium nitroprusside treatments increased the redox ratios. Cadmium
also adversely affected the seed yield and a greater decline was observed with long term Cd stress as compared to short term Cd
stress. Nitric oxide had a positive effect on seed yield and Cd accumulation. The study concludes that an exogenous supply of NO
protects chickpea plants from Cd toxicity.
