Impact of SiO2 Nanoparticles on Radish Growth, Enzyme Activity, and Nutrient Content under Saline Water Stress

This study aimed to investigate the reduction of stress and changes in nutrient content in radish (Raphanus sativus L.) plants under saline irrigation water conditions by applying nanosilica. The experiment involved four levels of salinity stress, represented by increasing electrical conductivity (EC) values of the saline water (SW; 0.6-control, 1.2, 2.4, and 3.6 dS m–1), and four doses of silica oxide nanoparticles (SiO2 NP-0, 100, 200, and 400 mg L–1). The main parameters measured included radish length, diameter, root weight, number of leaves, malondialdehyde (MDA), enzyme activities (SOD, CAT, and APX), and concentrations of macro- and micronutrients (Ca, Mg, K, P, Na, Fe, Cu, Zn, and Mn). The results showed that silica oxide nanoparticles significantly mitigated the adverse effects of salt stress on radish growth. The highest dose of silica oxide nanoparticles (SiO2NP400) increased radish root length by 7%, root diameter by 26%, root weight by 43%, and dry matter content by 21% compared to the control. Under the highest salinity level (SW3.6), silica oxide nanoparticles also improved root length, root diameter, root weight, and dry matter, thereby reducing the negative impact of salinity stress. Furthermore, SiO2NP400 increased Fe and Cu uptake by 8 and 34%, respectively. It has been determined that SiO2NPs primarily function as healing agents/stress protectors. Future studies are recommended to investigate the potential use of nanoparticles as a substitute for nutrients or as a source of nutrients.