Impact of Silver Nitrate on the Antioxidant System of Rosa canina L.

Dog rose is a plant species known for its strong antioxidant properties, primarily due to its high content of biologically active compounds. Silver nitrate (AgNO₃) is widely used in plant biotechnology as an ethylene action inhibitor, capable of delaying senescence and promoting plant development, as well as an antibacterial agent. However, silver ions can also exert phytotoxic effects by inducing excessive production of reactive oxygen species, potentially disrupting cellular homeostasis and causing oxidative stress. In this study, we investigated the effect of silver nitrate on the antioxidant system of Rosa canina L. We measured the activity of ascorbate oxidase, ascorbate peroxidase, guaiacol peroxidase, ascorbic acid, vitamin P, and thiol-containing compounds to assess both enzymatic and non-enzymatic antioxidant responses. Guaiacol peroxidase activity increased at all concentrations of AgNO₃, indicating activation of enzymatic defense mechanisms. The content of vitamin P increased at 10 and 50 mg/L, while ascorbic acid levels decreased at all concentrations. The concentration of high-molecular-weight thiols decreased at 50 mg/L. These findings provide valuable insights into the modulation of the antioxidant system in dog rose under silver-induced stress, highlighting the potential of R. canina as a model for studying plant responses to metal ions exposure. The obtained results may be useful for optimizing micropropagation protocols of R. canina and related species, as well as for using this system as a model to study metal-induced oxidative stress in plant tissues in vitro.