Chitooligosaccharide-Coated Silica Nanofibers: Synthesis and Its Effect on Germination and Seedling Growth of Peanut (Arachis hypogaea L.) and Date Palm Seeds (Phoenix dactylifera)

In this study, silica nanofibers were synthesized via a ZnO-assisted hydrothermal method to develop a novel nanofertilizer with promoted plant growth potential. The aim was to fabricate one-dimensional (1D) silica nanostructures and evaluate their effectiveness when combined with chitooligosaccharide as a seed treatment agent. Structural and morphological characterization was conducted using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy (HR-TEM), and Fourier transform infrared (FTIR) spectroscopy. The resulting silica nanofibers exhibited diameters ranging from 10 to 100 nm and a high surface area, with ZnO and ethylenediamine serving as key complexing and structure-directing agents in the nanofiber formation. The fibers were subsequently coated with chitooligosaccharide to form a nanofiber-based organic fertilizer. Its efficacy was tested on the germination and early seedling development of peanut ( Arachis hypogaea L.) and date palm ( Phoenix dactylifera ) seeds under four treatment conditions: control, chitosan alone, uncoated silica nanofibers, and chitooligosaccharide-coated silica nanofibers. The results demonstrated that seeds treated with the coated nanofiber fertilizer showed significantly higher germination rates and greater root and leaf lengths than other treatments. Specifically, the germination rates of peanut and date palm seeds treated with COS-coated SNF were approximately 1.25 times (0.989 vs. 0.789) and 1.57 times (0.97 vs. 0.79) higher than the respective controls. Regarding root development, COS-coated SNF increased root length by 1.45 times (119 mm vs. 81.8 mm) in peanut seedlings after 7 days and by 2 times (23.1 mm vs. 11.5 mm) in date palm seedlings after 17 days. Additionally, leaf growth in date palm was enhanced by 1.97 times (228.7 mm vs. 128.6 mm) after 30 days compared to the control. These results highlight the potential of COS-coated SNF as an effective nanofertilizer to promote early plant growth and development.