# In Vivo Biosynthesis of Au and Ag NPs Using Two _Medicago sativa_ L. Genotypes
## 3 Results
### Obtaining Plant Suspension from Seedings for Spectrophotometry
\begin{table}
\begin{tabular}{l l l} \hline \hline
**Precursor** & **Precursor Concentration (mg/L)** & **Light Wavelength (nm)** & **Absorption (u.a.) Values** \\ \hline \multirow{8}{*}{Control} & & 340-385, 387, 389, 392, 394, 397, 403-447 & \textgreater{}5.00 \\ \cline{3-4}  & & 386,388 & 4.79 \\ \cline{3-4}  & & 390–391, 393 & 4.49 \\ \cline{3-4}  & & 395–396 & \(\downarrow\) \\ \cline{3-4}  & & 398–402 & 4.19 \\ \cline{3-4}  & & 447–899 & \(\downarrow\) \\ \cline{3-4}  & & 900 & 0.93 \\ \hline \multirow{8}{*}{HAuCl\({}_{4}\)} & & 340–345 & 2.56 \\ \cline{3-4}  & & 364–899 & \(\downarrow\) \\ \cline{3-4}  & & 900 & 0.93 \\ \cline{3-4}  & & 340–345, 347 & \textgreater{}5.00 \\ \cline{3-4}  & & 346 & 4.79 \\ \cline{3-4}  & & 347–899 & \(\downarrow\) \\ \cline{3-4}  & & 900 & 0.47 \\ \cline{3-4}  & & 340–357, 360, 361 & \textgreater{}5.00 \\ \cline{3-4}  & & 358–359 & 4.79 \\ \cline{3-4}  & & 362–899 & \(\downarrow\) \\ \cline{3-4}  & & 900 & 0.51 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Highest and lowest light absorbance values in _’la Bella’_ after 48 h of AgNO\({}_{3}\) and HAuCl\({}_{4}\) exposure (green indicates results with maximum absorbance values (5.00), yellow indicates the results in which the absorption values are the highest but do not reach the maximum possible value (5.00), an arrow means a decrease in absorption results at the indicated wavelength of light). Figure 4: The results of light absorption for _la Bella_ genotype after 48 h of exposure to AgNO\({}_{3}\) and HAuCl\({}_{4}\). Two-beam photo-spectroscopy showed that control samples of both alfalfa genotypes had a light absorption peak between 5.00 and 4.5 when the samples received light with a wavelength between 340 and 460 nm. When light was received with a wavelength exceeding 460 nm, the absorption intensity decreased in all control samples and reached a minimum at 900 nm (<1.00). In both _'Kometa'_ and _'la Bella'_ samples of the experimental groups that received all concentrations of the HAuCl4 precursor for 24 h and almost all concentrations for 48 h, the wavelength period in which the maximum values of light absorption were observed decreased compared to the control group. The decrease depended on the precursor type and its concentration. As the concentration of the precursor increased, the maximum values of light absorption were shown less frequently than in the control groups. Samples were found where the light absorption peak did not reach the maximum value of 5.00. These were _'Kometa'_ genotype samples that received 250 and 1000 mg/L of the AgNO3 precursor with an exposure time of 24 h, as well as _'la Bella'_ samples that received the AgNO3 precursor with concentrations of 250 and 500 mg/L and an exposure time of 24 h.  
When the precursors were used for 48 h, samples were detected in which the light absorption peak did not reach the maximum value of 5.00. These results are shown in Table 4. These were the _'Kometa'_ genotype samples that received 100 and 200 mg/L of the HauCl4 precursor and samples that received 250 mg/L of the AgNO3 precursor. The _'la Bella'_ sample that received 50 mg/L of the HauCl4 precursor also differed significantly from the control. This was the only one of the HauCl4 samples to show such a considerable difference from the control. Additionally, _'la Bella'_ samples that received the AgNO3 precursor at all concentrations showed low absorption peaks with a short wavelength period. Determination of Light Absorbance Intensity at a Certain Wavelength by Spectrophotometry Using a NanoDrop1000 Spectrophotometer  
The absorbance of the light in the suspension solution was determined at light wavelengths of 470 and 350 nm for AgNO3 samples and 450 and 650 nm for HauCl4 samples. The NanoDrop1000 spectrophotometer differs from the two-beam Shimadzu UV-2550 PC UV-Vis spectrophotometer, in that absorbance is determined at a specific wavelength rather than a period. Each sample measurement was repeated in triplicate, and the light absorbance was determined at the selected wavelengths.