Cadmium (Cd) contamination is a serious agricultural and environmental hazard. The study investigates cross-protection roles of putrescine (Put, 0.2 mM) and nitric oxide (sodium nitroprusside; SNP, 1 mM) in conferring Cd (CdCl2, 1.5 mM) tolerance in mung bean (Vigna radiata L. cv. BARI Mung-2) seedlings. Cadmium stress increased root and shoot Cd content, reduced growth, destroyed chlorophyll (chl), modulated proline (Pro) and reduced leaf relative water content (RWC), increased oxidative damage [lipid peroxidation, H2O2 content, O2(∙-) generation rate, lipoxygenase (LOX) activity], methylglyoxal (MG) toxicity. Put and/or SNP reduced Cd uptake, increasd phytochelatin (PC) content, reduced oxidative damage enhancing non-enzymatic antioxidants (AsA and GSH) and activities of enzymes [superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST), and glutathione peroxidase (GPX)]. Exogenous Put and/or SNP modulated endogenous polyamines, PAs (putrescine, Put; spermidine, Spd; spermine, Spm), and NO; improved glyoxalase system in detoxifying MG and improved physiology and growth where combined application showed better effects which designates possible crosstalk between NO and PAs to confer Cd-toxicity tolerance.
Keywords: Environmental pollution; Heavy metal; Methylglyoxal; Reactive oxygen species; Signaling crosstalk.
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