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

Abstract

Lattice henbane<em> (Hyoscyamus reticulatus</em> L.) is an herbaceous, biennial plant belonging to Solanaceae family. <em>H. reticulatus</em> hairy roots were established from two-week-old leaves infected by A7 strain of <em>Agrobacterium rhizogenes</em> 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 Guaiacolperoxidase (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.