Silicon Nanoparticles Improve In Vitro Organogenesis of Citrus aurantium L. and Are Associated with Enhanced Antioxidant Activity

• Ali A. Zainel1

  Author

This study investigated the potential impact of silicon nanoparticles SiNPs on in vitro organogenesis of Citrus aurantium L. through regulation of oxidative stress and antioxidant defense. Nodal explants were grown in Murashige and Skoog (MS) media supplemented with SiNPs at varying doses (0, 50, 100, and 200 mg L⁻¹). The control treatment showed the lowest values for shoot induction, shoot multiplication, shoot length and rooting parameters than SiNPs treatments. Single shoot tip explants exhibited superior rooting performance (22.56±0.080 roots number) produced from a tissue-cultured simple shoot clone’s seedlings, at optimum level 100 mgL⁻¹ had shown the highest efficiency on tissue regeneration reaching 91.2% shoot induction and average number of shoots was recorded as around 5.87 ± 0.064 per explant. Additionally, SiNPs treatment significantly increased chlorophyll content and enhanced the activity of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). On the other hand, oxidative stress indicators such as malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) showed a substantial decline. Plants demonstrated optimum stress tolerance, as evidenced by a considerable increase in proline accumulation. However, at 200 mgL⁻¹, a decrease in several parameters was observed, suggesting potentially inhibitory effects at higher concentrations of nanoparticles. In conclusion, these findings suggest a potential role of silicon NPs in controlling homeostasis of reactive oxygen species and improved physiological stability in in vitro cultured citrus tissues. SiNPs’ efficacy was confirmed in micro-propagation, and optimal regeneration protocols for citrus rootstocks were developed.

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