Green synthesized TiO2 nanoparticles as a stimulator for aquaculture growth of Oryza sativa L.

Depleting agricultural land and water resources with growing human civilization demands an alternative way for faster and more sustainable crop production techniques to meet the current requirements. Recently, nanotechnology-aided hydroponic agriculture (aquaculture) systems have brought remarkable attention. In this context, the present investigation focuses on applying green synthesized TiO₂ nanoparticles in soil-free aquaculture systems to stimulate the germination and growth of Oryza sativa L. TiO₂ nanoparticles are synthesized using Dillenia indica fruit extract and characterized using various spectroscopic and microscopic techniques. X-ray diffraction pattern (XRD) confirms the anatase phase of the synthesized TiO₂ nanoparticles with an average crystallite size of 6.34 nm. Field emission scanning electron microscopy (FESEM) images exhibit spherical morphology, and high-resolution transmission electron microscopy (HRTEM) analysis indicates the most nanoparticles of sizes below 10 nm. The BET surface analysis indicates the mesoporous nature of synthesized nanoparticles, and their pore sizes are distributed between 1 and 10 nm as confirmed by BJH analysis, which is very similar to the result obtained from HRTEM images. Green synthesized TiO₂ nanoparticles in Hoagland nutrient solution enhance germination and growth of Oryza sativa L. via soil-free aquaculture relative to previously commercially produced TiO₂ nanoparticles and other metal oxide nanoparticles. Among different concentrations of synthesized TiO₂ nanoparticles, a particular concentration (10 mg/L) in the nutrient solution efficiently stimulates germination and growth for Oryza sativa L., relative to the control system. TiO₂ nanoparticles with a higher specific surface area adsorb nutrients and facilitate nutrient translocation with improved water uptake inside plants, thus stimulating plant growth and increasing fresh and dry biomass.