## 4 Conclusions  
This study investigated the Mg NP/GW nanocomposite and its effects across various parameters. FTIR spectra revealed distinctive peaks indicating functional groups such as O-H stretching vibrations, aromatic C=C stretching, amide II, and C-O bonds. SEM images confirmed aggregation of Mg nanoparticles on GW powder, and EDX analysis verified elemental composition with magnesium present at low atomic percentage (\(\sim\)1%). The nanocomposite exhibited a slight increase in hydrodynamic size post-Mg precipitation, suggesting aggregation or surface modifications. XRD patterns indicated a crystalline nature without significant MgO formation, suggesting surface oxide formation. In seed germination studies, lower concentrations (0.5 g/L) of Mg NP/GW and GW enhanced seed germination rates, while higher concentrations (5.0 g/L) inhibited germination, demonstrating a concentration-dependent response. High concentrations of Mg NP/GW (5.0 g/L) showed toxicity effects on seed germination, potentially due to physiological alterations or structural interference. In _P. graveolens_, GW (0.5 g/L) and Mg NP/GW (0.5 g/L) treatments enhanced shoot length, leaf number, and biomass, with GW showing particular effectiveness in promoting shoot length. Both treatments upregulated FPPS1 and GPPS1 gene expression in _P. \begin{table}
\begin{tabular}{l l l l} \hline \hline
**Gene Name** & \multicolumn{2}{c}{**Primer Sequence**} & **Accession No.** & **Tm (\({}^{\circ}\)C)** \\ \hline \multirow{2}{*}{**FPPS1**} & F & 5\({}^{\prime}\)-CCGATGATTCTGCCCAATGGG-3\({}^{\prime}\) & \multirow{2}{*}{At5g47770} & \multirow{2}{*}{58 \({}^{\circ}\)C} \\ \cline{2-2} \cline{4-4}  & R & 5\({}^{\prime}\)-CCATTCAATGCACCACCAGTG-3\({}^{\prime}\) & & \\ \hline \multirow{2}{*}{**GPPS1**} & F & 5\({}^{\prime}\)-CCAAATGCCTCGTCAT-3\({}^{\prime}\) & \multirow{2}{*}{At5g49530} & \multirow{2}{*}{58 \({}^{\circ}\)C} \\ \cline{2-2} \cline{4-4}  & R & 5\({}^{\prime}\)-ATTAGAGCTCAAGCTCAAAAGG-3\({}^{\prime}\) & & \\ \hline \multirow{2}{*}{\(\upbeta\)**-Actin**} & F & 5\({}^{\prime}\)-GTGCCCCATTCAGAAGGATA-3\({}^{\prime}\) & \multirow{2}{*}{AB181991} & \multirow{2}{*}{58 \({}^{\circ}\)C} \\ \cline{2-2} \cline{4-4}  & R & 5\({}^{\prime}\)-GAAGACTCCATCCGCATCAT-3\({}^{\prime}\) & & \\ \hline \multirow{2}{*}{**GAPDH**} & F & 5\({}^{\prime}\)-TTGTTCCACTGCATTCGTT-3\({}^{\prime}\) & \multirow{2}{*}{CA254672} & \multirow{2}{*}{} \\ \cline{2-2} \cline{4-4}  & R & 5\({}^{\prime}\)-CTGATCCACCTGTTGT-3\({}^{\prime}\) & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Oligonucleotide primers used in qRT-PCR analysis. gravelopens_ and _S. alba_, with GW NPs generally inducing higher fold changes compared to Mg NPs. In cytogenetic studies using _Allium cepa_, lower concentrations of Mg NP/GW (0.5 g/L) increased the mitotic index, while higher concentrations (5.0 g/L) decreased it, indicating a dual effect on cell division. Mg NP/GW treatments also induced various aberrations in chromosome behavior, suggesting potential cytotoxic effects at higher concentrations. Overall, the Mg NP/GW nanocomposite exhibited unique physical, chemical, and biological properties influenced by nanoparticle concentration and interaction with the substrate material. This study underscores the importance of dose-dependent application in agricultural practices to harness beneficial effects while mitigating potential adverse impacts. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/molecules29143394/s1](https://www.mdpi.com/article/10.3390/molecules29143394/s1)]([https://www.mdpi.com/article/10.3390/molecules29143394/s1](https://www.mdpi.com/article/10.3390/molecules29143394/s1)), Table S1: Effects of Mg NPs/GW on mitotic abnormalities in _Allium cepa_; Table S2: Effects of Mg NPs/GW on mitotic cell division in _Allium cepa_. Funding acquisition, D.H.M.A. ; Methodology, M.M.K. and R.M. ; Validation, M.M.K. and Y.G. ; Visualization, M.M.K., A.B. and W.N.H. ; Writing--original draft, M.M.K. Supervisors, W.N.H. and A.B.