# In Vivo Biosynthesis of Au and Ag NPs Using Two _Medicago sativa_ L. Genotypes
## 3 Results
### Obtaining Plant Suspension from Seedings for Spectrophotometry  
Despite the small size of the seedlings, plant green mass suspensions for spectrophotometric analysis were obtained from all experimental groups. When evaluating the external appearance of the suspension, no drastic colour changes were observed. No deposits or particles of other materials were observed. However, the green colour of some samples was darker. Determination of Light Absorbance at Different Wavelengths from 340 to 900 nm with a Two-Beam Shimadzu UV-2550 PC UV-Vis Spectrophotometer  
Using a two-beam Shimadzu UV-2550 PC UV-Vis spectrophotometer, light absorbance was determined at different wavelengths from 340 to 900 nm. Light absorbance results for each alfalfa genotype, depending on the precursor and its exposure time, are summarised in graphs of Figures 1-4. The results of light absorption for the _'Kometa'_ genotype after 24 h exposure to AgNO\({}_{3}\) and HAuCl\({}_{4}\) are shown in Figure 1.  
The most significant changes in the light absorption results compared to the control for the _'Kometa'_ genotype after 24 h of exposure to the precursors are summarised in Table 1. \begin{table}
\begin{tabular}{l l l l} \hline \hline
**Precursor** & **Precursor Concentration (mg/L)** & **Light Wavelength (nm)** & **Absorption (u.a.) Values** \\ \hline \multirow{4}{*}{Control} & & 340–391, 399–444 & \textless{}5.00 \\ \cline{3-4}  & & 392–399 & 4.49 \\ \cline{3-4}  & & 448–899 & \(\downarrow\) \\ \cline{3-4}  & & 900 & 0.67 \\ \hline \multirow{4}{*}{HAuCl\({}_{4}\)} & & 340–364, 434, 437, 440 & \textless{}5.00 \\ \cline{3-4}  & & 435–439 & \(\downarrow\) \\ \cline{1-1} \cline{3-4}  & 50 & 441–899 & \(\downarrow\) \\ \cline{1-1} \cline{3-4}  & & 900 & 0.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Highest and lowest light absorbance values in ‘_Kometa’_ after 24 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 1: The results of light absorption for the ‘_‘Kometa’_ genotype after 24 h of exposure to AgNO\({}_{3}\) and HAuCl\({}_{4}\). The results of light absorption for the _'la Bella'_ genotype after 24 h of exposure to AgNO\({}_{3}\) and HauCl\({}_{4}\) are shown in Figure 2.  
The most significant changes in the light absorption results compared to the control for the _'la Bella'_ genotype after 24 h of exposure to the precursors are summarised in Table 2. \begin{table}
\begin{tabular}{l l l l} \hline
**Precursor** & **Precursor Concentration (mg/L)** & **Light Wavelength (nm)** & **Absorption (u.a.) Values** \\ \hline \multirow{6}{*}{HAuCl\({}_{4}\)} & \multirow{3}{*}{100} & 340–448 & \textgreater{}5.00 \\ \cline{3-4}  & & 449–899 & \(\downarrow\) \\ \cline{3-4}  & & 900 & 0.64 \\ \cline{3-4}  & & 340–449 & \textgreater{}5.00 \\ \cline{3-4}  & 200 & 450–899 & \(\downarrow\) \\ \cline{3-4}  & & 900 & 0.70 \\ \hline \multirow{6}{*}{AgNO\({}_{3}\)} & \multirow{6}{*}{500} & 341 & 4.31 \\ \cline{3-4}  & & 340 & 4.09 \\ \cline{3-4}  & & 345–899 & \(\downarrow\) \\ \cline{3-4}  & & 900 & 0.39 \\ \cline{3-4}  & & 340–345 & \textgreater{}5.00 \\ \cline{3-4}  & & 446, 447 & 4.79 \\ \cline{3-4}  & & 348 & 4.31 \\ \cline{3-4}  & & 349 & 4.09 \\ \cline{3-4}  & & 350–899 & \(\downarrow\) \\ \cline{3-4}  & & 900 & 0.5 \\ \hline \multirow{6}{*}{1000} & \multirow{6}{*}{1000} & 340 & 4.57 \\ \cline{3-4}  & & 341 & 3.52 \\ \cline{3-4}  & & 342, 343 & 3.47 \\ \cline{1-1} \cline{3-4}  & & 344–899 & \(\downarrow\) \\ \cline{1-1} \cline{3-4}  & & 900 & 0.5 \\ \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
Figure 2: The results of light absorption for the _’la Bella’_ genotype after 24 h of exposure to AgNO\({}_{3}\) and HauCl\({}_{4}\).