## 2 Results and Discussion
### Effect of Nanoparticle on Mitotic Division
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Replicates**} & **Concentration** & **Number of** & **Counted** & **Normal** & **Normal** & **Sticky** & **Laggard** & **Chromosomal** & **Bridge** & **Disturbed** \\  & **(g/L)** & **Cells** & **Metaphase** & **Anophase** & **Chromosome** & **Chromosome** & **Bridge** & **Metaphase** \\ \hline Control & 0.0 & 1000 & + & + & – & – & – & – \\ Nanoparticle & 0.5 & 1000 & + & + & + & + & – & – \\ (0.5 g/L) & 1.0 & 1000 & + & + & + & – & + & + \\ Nanoparticle & 5.0 & 1000 & + & – & + & + & + & + \\ (5.0 g/L) & \multicolumn{2}{c}{**Concentration**} & \multicolumn{2}{c}{**Mean \(\pm\) SE**} & \multicolumn{2}{c}{**Miotic**} & \multirow{2}{*}{**Telophase**} & \multirow{2}{*}{**Anophase**} & \multirow{2}{*}{**Metaphase**} & \multirow{2}{*}{**Prophase**} & **Dividing** \\  & **of Mg NP/GW** & **(\%) \({}^{\star}\) & & & & & & **Cell** \\  & **(g/L)** & & & & & & & **(Total)** \\ \hline Control & 0.0 & 44.6 \(\pm\) 2.16 & 45.8-50.1 & 0-2 & 1–5 & 2–4 & 380–493 & 386–501 \\ Nanoparticle & 0.5 & 61.24 \(\pm\) 1.79 & 54.6–64.5 & 0-3 & 1–8 & 4–16 & 530–640 & 546–645 \\ Nanoparticle & 1.0 & 36.96 \(\pm\) 0.86 & 34.6–39.2 & 0-1 & 1–3 & 1–2 & 340–390 & 346–392 \\ Nanoparticle & 5.0 & 27.36 \(\pm\) 1.34 & 24.1–31.7 & 0 & 0–1 & 0–2 & 240–315 & 241–317 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Effects of Mg NP/GW on mitotic abnormalities and cell division in _Allium cpa_. Figure 9: Representative examples of normal and abnormal cell divisions in onion root tips subjected to the various treatments of GW and Mg NP/GW nanoparticles (**A–D**): normal prophase, metaphase, anaphase, and telophase, respectively, under control conditions. (**E**): Multiple bridges; (**F**): stickiness in anaphase; (**G**): lagging in anaphase; (**H**): C-shaped metaphase; (**I**): stickiness in metaphase; (**J**): stickiness in metaphase; (**K**): DNA decay; (**L**): breaks and disturbance. (1.0 g/L and 5.0 g/L) show a decrease in the mitotic index, indicating cytotoxic effects that inhibit cell division. These changes reflect the nanoparticles' disruptive impact on the cell cycle. Previous studies have established that nanoparticles can exert significant cytotoxic effects on plant cells. For instance, research on silver nanoparticles (AgNPs) demonstrated their ability to disrupt cellular processes and induce oxidative stress, leading to cell cycle arrest and apoptosis [44; 46]. Similar findings are reported for titanium dioxide (TiO\({}_{2}\)) nanoparticles, where exposure led to decreased mitotic indices and increased frequencies of chromosomal aberrations in _Allium cepa_ root tips [47]. The analysis of the presented figure aligns with these findings, showing a marked increase in mitotic abnormalities and changes in the mitotic index upon treatment with GW and Mg NP/GW nanoparticles. The data in Table 4 supports this by illustrating the variations in the mitotic index and stages of cell division with increasing nanoparticle concentrations. Nanoparticles are known to cause genotoxic effects, leading to various chromosomal aberrations. Studies have shown that exposure to zinc oxide (ZnO) nanoparticles induces chromosomal stickiness, bridges, and laggards in plant cells, highlighting their potential to disrupt mitotic spindle formation and chromosome segregation [48; 49]. The abnormalities observed in the provided figure, such as multiple bridges, stickiness, and lagging chromosomes, are consistent with these genotoxic effects. The quantitative data from Table 4 further corroborate these findings, showing increased frequencies of such abnormalities with nanoparticle treatments. One of the primary mechanisms through which nanoparticles exert their toxic effects is the generation of reactive oxygen species (ROS). ROS can cause oxidative stress, leading to lipid peroxidation, protein oxidation, and DNA damage [50; 51]. This is evident in the study by [52], which demonstrated increased ROS production and DNA strand breaks in plants exposed to various metal nanoparticles.