Prospects of Selenium Nanoparticles for Enhancing Stevia rebaudiana Bertoni In Vitro Multiplication and Bacterial Growth Suppression

As is well known, selenium nanoparticles (SeNPs) are readily taken up by plants, exhibit high bioavailability, and enhance plant organogenesis in situ, while also demonstrating antibacterial properties. These characteristics offer broad prospects for their application during in vitro plant micropropagation. We identified effective concentrations of SeNPs measuring 10–45 nm and 50–100 nm that stimulated the in vitro multiplication of Stevia rebaudiana Bertoni. Treatment with 50 μg L−1 SeNPs (10–45 nm) increased the number of shoots 3.5-fold, fresh weight (FW) 2.2-fold, and the plant multiplication factor 2.8-fold; treatment with 100 μg L−1—by 5.4-, 5.2-, and 4.2-fold, respectively. Larger SeNPs (50–100 nm) also promoted plant growth, increasing the number of shoots by 3.1- and 3.8-fold and FW by 3.2- and 2.2-fold at concentrations of 10 and 20 mg L−1, respectively. The dry matter content was 38–45% lower, although no visible hyperhydration was observed. Only SeNPs measuring 50–100 nm caused moderate, concentration-dependent inhibition of Pectobacterium carotovorum growth, which was most pronounced at concentrations of 20–200 mg L−1. Thus, SeNPs have considerable potential as multifunctional supplements to culture media for plant clonal micropropagation.