Hydroxyapatite nanoparticles as novel nano-fertilizer for production of rosemary plants

Nano-fertilizers are new materials produced by means of nanotechnology and may soon replace conventional fertilizers. Nanomaterials including nanoparticles are characterized by rapid absorption and controlled delivery of nutrients in plants. In the current study, hydroxyapatite, i.e., calcium phosphate, nanoparticles (HAP NPs) were developed as a novel phosphorus nano-fertilizer and evaluated for the growth characters, essential oil content, and histological changes in rosemary (Rosmarinus officinalis L.) plants. For comparison, the NPK fertilizer was used. The results showed that compared to the traditional form NPK, nano-HA at 0.5 and 1.0 g/L enhanced the growth character and essential oil production along with its major constituents during both cuts. The levels of rosemary oil components including α-pinene, eucalyptol, camphor, endo-borneol and verbenone were higher in the nano-fertilizer group than in the control group. Furthermore, the highest values of the stem diameter, fiber thickness, phloem tissue thickness, xylem tissue thickness, pith diameter of the stem and the midvein thickness and lamina thickness of the leaf were obtained with nano-fertilizer. In conclusion, the data demonstrate that hydroxyapatite nanoparticles as a nano-fertilizer showed great potential to improve the productivity of rosemary plants. This approach opens a new avenue for exploring nanomaterials as an alternative technology to traditional fertilizers used in medicinal and aromatic plant culture.