Exogenous sodium nitroprusside increases antioxidative potential and grain yield of bread wheat exposed to cadmium

The cadmium accumulation declines the crop productivity by disturbing the metabolism of plant. Thus, it is very essential to know the process of Cd effects through Cd-induced physio-biochemical determinations as well as its accretion, carrying and the associations with development, mineral nutrients and the antioxidant systems. The experiments were conducted under different Cd (control, 0.3, 0.6, 0.9 and 1.2 mM) regimes without or with an exogenous NO donor, sodium nitroprusside (0.15 and 0.30 mM SNP) on four cultivars of wheat (Punjab-2011, AARI-2011, Millat-2011 and Sehar-2006). The exogenous SNP was effective in improving growth of Cd-stressed wheat plants. Cd stress caused a noticeable repression in flavaniods, total phenolics, soluble proteins, and grain yield components while increased total free ascorbic acid (AsA), proline, glycinebetain (GB), glucose and sucrose, malondialdehyde (MDA), hydrogen peroxide (H2O2) and the activity of enzymes including catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and peroxidase (POD) irrespective of wheat cultivars. More effective of both SNP levels was 0.30 mM. Of wheat cultivars, Punjab-2011 and AARI-2011 performed better than Millat-2011 and Sehar-2006. The exogenous NO was effective in improving total flavaniods, total phenolics, soluble proteins, and grain yield components under Cd stress. Furthermore, NO reversed the effects of Cd on reducing and non-reducing sugars, proline, total free amino acids, H2O2, MDA and enzyme activity of APX, CAT and POD irrespective of wheat cultivars. Overall, the results elaborated that exogenously applied NO reduced the Cd toxicity in wheat.