Plant-based nano-fertilizer prepared from Paulownia Tomentosa: fabrication, characterization, and application on Ocimum basilicum

Abstract

Abstract Background The use of hazardous and toxic chemical material has become limited by the green synthesis of nano-particles (NPs) from plants and other living organisms. In the current study, a new nano-fertilizer was green synthesized from Paulownia tomentosa leaves and then its effectiveness in alleviation of drought stress in Ocimum basilicum was investigated. Five concentrations of nano-fertilizer (0, 50, 70, 90 and 110 ppm) at three irrigation regimes including 100% of field capacity (IRF100), 75% of field capacity (IRF75), and 50% of field capacity (IRF50) were evaluated. Nano-fertilizers were prepared using the green hydrothermal method. Results Based on TEM analyses nanoparticles sizes were 5–8 nm. The results of FTIR appearance indicated the main distinctive peaks of the Paulownia-based nano-fertilizer (NFPs) in the spectrum. In addition, the nitrogen peaks in the XPS spectra indicate that the prepared carbon dots NFPs are nitrogen-doped. Moreover, there are functional groups, such as COOH or OH groups on the surface of Paulownia-based nano-fertilizer (NFPs). The results illustrated that drought stress increased proline (73%), alcohol-soluble carbohydrates (78%), and malondialdehyde (41%) in comparison with normal irrigation; in contrast, soluble proteins (73%), Chlorophyll a (46%), Chlorophyll b (39%), Chlorophyll total (42%), and carotenoid (77%) were reduced in the same condition. The O. basilicum biological yield was reduced in moderate (12.40%) and severe (24.42%) drought stress in comparison with full irrigation conditions (IRF100). Paulownia-based nano-fertilizer (NFPs) caused an increase in soluble proteins and photosynthetic pigments. Application of NFP-90 reduced the production of proline and malondialdehyde, respectively, 51.8% and 30.8% compared to non-application under severe stress conditions, which indicates alleviated the adverse effect of drought stress. The highest biological yield of basil was obtained at a 110 ppm concentration of NFPs. Conclusion Overall, results showed that using NPs biosynthesized from Paulownia leaves could be an economically and environmentally friendly method as a nano-fertilizer. Graphical Abstract