Protective role of nitric oxide against arsenic-induced damages in germinating mung bean seeds

Nitric oxide (NO) is a bioactive gaseous, multifunctional molecule playing a central role and mediating a variety of physiological processes and responses to biotic and abiotic stresses including heavy metals. The present study investigated whether NO applied exogenously as sodium nitroprusside (SNP) has a protective role against arsenic (As) toxicity (applied as sodium arsenate) in Vigna radiata (mung bean) germinating seeds. Treatment with 75 mu M SNP significantly improved mung bean seed germination, growth, and decreased the As-accumulation. Furthermore, As-induced oxidative stress measured in terms of malondialdehyde and H2O2 contents was lesser upon supplementation of SNP indicating a reactive oxygen species scavenging activity of NO. In addition, supplementation of SNP markedly decreased the activity of superoxide dismutase and stimulated catalase, alpha-amylase, protease and slightly changed the H+-ATPase activity.