Effects of Silicon and AgNO3 Elicitors on Biochemical Traits and Antioxidant Enzymes Activity of Henbane (Hyoscyamus reticulatus L.) Hairy Roots

Lattice henbane (Hyoscyamus reticulatus L.) is an herbaceous, biennial plant belonging to Solanaceae family. H. reticulatus hairy roots were established from two-week-old leaves infected by A7 strain of Agrobacterium rhizogenes on solid Murashige and Skoog (MS) medium. In this study, abiotic elicitors including; Sodium silicate (Na2SiO3) with different concentrations (0, 1, 5 and 7 mM) and silver nitrate (AgNO3) concentrations (0, 0.5, 1 and 2 mM) were added to hairy roots culture media. The results showed that, Na2SiO3 and AgNO3 significantly affected hairy roots fresh weight after 24h. Also, the highest hairy root fresh weight was observed in the control, and with broadening elicitor concentrations, fresh weight was decreased in both treated hairy roots with AgNO3 and Na2SiO3 but the effect of exposure duration was not significant. Biochemical analysis showed that total antioxidant activity (TAA), total phenol (TP), catalase (CAT), ascorbate peroxidase (APX) and Guaiacol peroxidase (GPX) activities were enhanced in elicitated hairy roots compared to non elicitated hairy roots. The highest CAT, APX and GPX activities were observed in hairy roots treated with 7mM Na2SiO3 and 2mM AgNO3. Our results suggest that, Na2SiO3 and AgNO3 can stimulate the antioxidant defense systems and protect the plants from subsequent stresses.