Silicon nanoparticle(s) induced morpho-anatomical traits and improved micropropagation of white fleshed dragon fruit [Selenicereus undatus (Haworth)]

Silicon nanoparticles (SiNPs) improve plant growth and yield by enhancing nutrient uptake and stress tolerance. These nanoparticles boost plant defense mechanisms against pathogens and environmental challenges. In this study, seedlings-derived explants of white-fleshed dragon fruit (Selenicereus undatus) were used for differentiation and high-frequency shoot regeneration on Murashige and Skoog (MS) medium with 6-benzylaminopurine (BAP, 0.5 mg L⁻¹) and α-naphthalene acetic acid (NAA, 0.25 mg L⁻¹). The complementation of 3.0 mg L⁻¹ SiNPs in the optimized nutrient medium enhanced the shoot multiplication rate to 23.0 cladodes per explants. The regenerated cladodes were structurally well-suited with thick cuticles, well-developed epidermis, hypodermis, aquiferous cortex, and collateral vascular bundles compared to the control and other concentrations of SiNPs tested. SiNPs promoted the development of 3-5 aerial and adventitious roots per cladode enabling preferred direct hardening of cloned plants on soilrite ex vitro. The morphological transformations improved by SiNPs, including the formation of robust cladode and spines, played a pivotal role in achieving a high rate of acclimatization success (96%) in the field. The incorporation of SiNPs in vitro at the shoot amplification stage of micropropagation of S. undatus induced morphogenesis and structural changes, and promoted qualitative and quantitative improvements in the regenerated cladodes which helped in enhanced survival of plants in vivo.