Effect of Sodium Nitroprusside on Antioxidant Enzymes and Phenylpropanoid Pathway of Ginger Rhizomes

Ginger rhizomes were used as materials to study the effect of sodium nitroprusside (SNP) dipping at different concentration for 10 min on the respiratory intensity and weight loss to screen the optimal concentration of SNP. The changes of antioxidant enzymes activities, key enzymes in phenylpropanoid pathway and metabolites accumulation in ginger rhizomes after SNP treatment were also studied. The results indicated that 0.25 mmol/L SNP treatment decreased the respiratory intensity and inhibited the increase of weight loss. SNP treatment significantly increased the content of hydrogen peroxide (H₂O₂) and the activity of superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) in ginger rhizomes. The results also showed that SNP treatment enhanced the activity of phenylalanine ammonia-lyase (PAL) and significantly increased 4-coumarate/coenzyme A ligase (4CL) activity to activate the accumulation of lignin, total phenolic compounds and flavonoids in ginger rhizomes. These results suggested that SNP delay senescence of ginger rhizomes by modulating antioxidant enzymes and phenylpropanoid pathway.