## 3 Results and Discussion
### Profiling of VOCs and Their Distribution
**} & \multicolumn{1}{c}{**Compound**} & \multicolumn{1}{c}{**RI \({}^{1}\)**} & \multicolumn{1}{c}{**Classification**} & \multicolumn{4}{c}{**DAS**} \\ \cline{4-7}  & & & **30** & **60** & **70** & **80** \\ \hline
1 & (_Z_)-3-Hexanal & 802 & Aldehyde & 0.04 \(\pm\) 0.01 & ND & ND & ND \\
2 & (_E_)-2-Hexanal & 857 & Aldehyde & 0.45 \(\pm\) 0.02 a & 0.32 \(\pm\) 0.06 a & 0.05 \(\pm\) 0.01 b & 0.07 \(\pm\) 0.04 b \\
3 & (_E_,_E_)-2,4-Hexadien & 913 & Aldehyde & 0.04 \(\pm\) 0.00 & ND & ND & ND \\
4 & 1-Octen-3-ol & 981 & Fatty alcohol & 0.06 \(\pm\) 0.01 b & 0.11 \(\pm\) 0.01 a & 0.02 \(\pm\) 0.00 c & 0.04 \(\pm\) 0.00 b \\
5 & 9-Pinene & 983 & Monoterpene & ND \({}^{2}\) & 0.12 \(\pm\) 0.01 a & ND & 0.02 \(\pm\) 0.01 b \\
6 & 9-Myrene & 993 & Monoterpene & ND & 0.13 \(\pm\) 0.05 a & ND & 0.02 \(\pm\) 0.01 b \\
7 & L-Limonene & 1030 & Monoterpene & ND & 0.14 \(\pm\) 0.03 & ND & ND \\
8 & Eucalypt & 1033 & Monoterpene & 1.61 \(\pm\) 0.25 b & 5.64 \(\pm\) 1.34 a & 0.09 \(\pm\) 0.01 b & 1.22 \(\pm\) 0.41 b \\
9 & cis-4-Thujan & 1072 & Terpene alcohol & 0.11 \(\pm\) 0.01 a & 0.17 \(\pm\) 0.03 a & ND & ND \\
10 & 4-Methyl benzaldehyde & 1079 & Aldehyde & 2.24 \(\pm\) 0.34 a & ND & 0.33 \(\pm\) 0.04 b & 0.32 \(\pm\) 0.04 b \\
11 & Linalool & 1101 & Terpene alcohol & 1.45 \(\pm\) 0.46 b & 15.30 \(\pm\) 1.55 a & 0.85 \(\pm\) 0.55 b & 15.26 \(\pm\) 6.71 a \\
12 & (_Z_)-Thujone & 1105 & Monoterpene & 0.11 \(\pm\) 0.02 & ND & ND & ND \\
13 & L-Camphor & 1146 & Monoterpene & 0.18 \(\pm\) 0.03 b & 0.40 \(\pm\) 0.02 a & ND & ND \\
14 & 8-Terpineol & 1167 & Terpene alcohol & 0.24 \(\pm\) 0.01 a & 0.38 \(\pm\) 0.06 a & 0.36 \(\pm\) 0.18 a & 0.14 \(\pm\) 0.04 a \\
15 & endo-Borneo & 1169 & Terpene alcohol & ND & ND & 0.05 \(\pm\) 0.01 a & 0.03 \(\pm\) 0.01 ab \\
16 & Terpine-4-ol & 1179 & Terpene alcohol & 0.05 \(\pm\) 0.00 b & 0.13 One commonality among all plant species was the presence of (_E_)-2-hexanal, a naturally occurring volatile C6 aliphatic aldehyde compound [75]. It acts as a germination inhibitor [76] and accumulates as a product of lipid peroxidation during the germination process [77]. These aldehydes result from the degradation of hydroperoxides, which are produced from the conversion of unsaturated fatty acids compositing the main membrane of lipids susceptible to peroxidation into free radicals and C6/C9 hydroperoxides [78]. The accumulation of (_E_)-2-hexanal at 30 DAS indicated the germination process, while its decrease after 60 DAS signified the transition to the growth stages. Additionally, for the dominant volatile compounds, all the plant species showed an increased tendency in the initial vegetative stages, followed by a decrease in total VOCs content over time, coinciding with a decrease in the main component. In the case of AR (Table 3), a total of 16 compounds were identified and these consist of aldehydes (2), fatty alcohol (1), monoterpenes (4), sesquiterpenenes (3), terpene alcohols (2), and phenylropenes (4). A significant effect of the growth stage on total VOCs was observed by varied total VOCs content. It varied from 71.7 \(\pm\) 7.0 ng/mg at 70 DAS to 243.4 \(\pm\) 21.3 ng/mg at 60 DAS. As depicted in Figure S3, the phenylropene group constituted a substantial proportion, ranging from 96.7% to 97.8% of the total VOCs. The dominance was primarily attributed to the presence of estragole, the most abundant compound. Changes in estragole content influenced the overall total content, with a notable increase up to 60 DAS (S2), followed by a sharp decrease. AR proved to be a rich source of  
\begin{table}
\begin{tabular}{l l c c c c c} \hline \hline \multicolumn{1}{c}{**No.