EFFECT OF NANOSTRUCTURES BIOSTIMULANTS AND BIOISOLATES ON MORPHOLOGICAL, PHYSIOLOGICAL AND ANATOMICAL CHARACTERISTICS OF BASIL (OCIMUM SPECIES)

Abstract

The present study evaluated the effects of nanostructured zinc-based nano-biostimulants and nano-bioisolates on the morphological, physiological, and anatomical characteristics of basil (Ocimum basilicum L. and Ocimum tenuiflorum L.). A factorial randomized complete block design (RCBD) was employed with two species and thirteen treatments, including control and three concentrations (25, 100, and 250 mg L⁻¹) of nano-biostimulants and nano-bioisolates, applied through soil drenching. Data were analyzed using Fisher's analysis of variance (ANOVA). Tukey's test was used to compare treatment means at a 5% probability level. The results demonstrated that all nano-enabled treatments significantly (P ≤ 0.05) enhanced plant growth, physiological efficiency, and root anatomical development compared to the control. Among treatments, sodium nitrophenolate-based nano-biostimulants (SNP-Zn NPs) showed the highest effectiveness, resulting in maximum plant height (192.78 cm), branching (193.26), leaf area (400.58 cm²), fresh biomass (489.83 g), and dry weight (169.64 g) in O. basilicum. Physiological parameters, including photosynthetic rate (24.21 μmol m⁻² s⁻¹), stomatal conductance (400.58 mmol m⁻² s⁻¹), transpiration rate (20.25 mmol m⁻² s⁻¹), and chlorophyll content (49.47 μmol m⁻²), were significantly improved under SNP-Zn NP treatments. Root anatomical traits such as epidermal thickness (4001.83 µm), aerenchyma cell area (2219.50 µm²), metaxylem area (501.78 µm²), and phloem area (24.21 µm²) were also markedly enhanced, indicating improved structural and functional efficiency. Linalool-based nano-bioisolates ranked second, followed by eucalyptol-based formulations, whereas chlormequat chloride-based nano-biostimulants exhibited comparatively lower responses. Overall, O. basilicum showed higher absolute values, while O. tenuiflorum exhibited greater proportional responses. These findings highlight the potential of functionalized Zn NPs, particularly sodium nitrophenolate-based nano-biostimulants, for improving crop performance and advancing sustainable agricultural practices.