# Dynamics of Monoterpene Formation in Spike Lavender Plants
## 2 Results  
### GC/MS Analysis  
GC/MS analysis of chloroform extracts from WT plants allowed the detection of most of the components of the spike lavender essential oil [48; 49] including monoterpenes, sesquiterpenes and, at longer retention times, over 21 min, coumarin, as previously reported [49; 37] (data not shown). Over 50 samples were used in order to adjust the extraction, labelling and GC/MS measuring conditions (Table S1). Total excess of \({}^{13}\)C abundance and the relative contributions of isotopomers (containing 1 or more \({}^{13}\)C-atoms, indicated by M+1, M+2,..., M+10, respectively) in the \({}^{13}\)C-enriched fraction of camphor and 1,8-cineole of selected samples are depicted in Figure 3A,B. More specifically, the labelling profiles shown in Figures S1 and S2 indicated that a pulse period below five hours did not lead to significant \({}^{13}\)C enrichments in both camphor and 1,8-cineol. However, \({}^{13}\)CO\({}_{2}\) pulses of five hours and more resulted in \({}^{13}\)C-enrichments of \(>\)2% (Figure 3A,B). Some of the samples showed \({}^{13}\)C enrichments of more than 10% (up to 25% in some cineole and camphor samples (Figure 3). Even experiments with a given pulse period (i.e., the said 5 h) showed considerable differences of labelling profiles that can be explained, in part, on the basis of different chase periods. Generally, it appeared that the \({}^{13}\)C enrichments increase with higher chase periods (Figures S1 and S2). To interpret the data in more detail, samples 48, 49, 50, 55, 31, 32, 43, 42 and 30, all of them with isotopologue excess values over 2.5% were chosen (Figure 3 and Table 1). Values for the isotopomers M+2 and M+3 and their ratios for both camphor and cineole are presented in Table 1. In all of these samples, the M+1 to M+3 fraction ranged from 25-73% of total labelled excess isotopologues. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & & & & & & & & \\ \hline \hline \multicolumn{2}{c}{} & Pulse time (h) & Chase time (h) & Sample & M+2 & M+3 & M+2/M+3 & M+2/(M+2 + M+3) \\ \hline \multirow{5}{*}{**Camphor**} & 4.9 a & 95 & 55 & 2.72 & 2.80 & 0.97 & 0.49 \\  & 5.0 a & 168 & 31 & 2.78 & 1.91 & 1.45 & 0.59 \\  & 5.0 a & 264 & 42 & 3.65 & 2.25 & 1.63 & 0.62 \\  & 5.1 a & 16 & 48 & 0.29 & 0.34 & 0.86 & 0.46 \\  & 5.1 a & 16 & 49 & 0.44 & 0.48 & 0.90 & 0.47 \\  & 5.1 a & 40 & 50 & 0.54 & 0.54 & 1.00 & 0.50 \\  & 5.2 a & 192 & 32 & 4.86 & 3.53 & 1.38 & 0.58 \\  & 5.2 a & 240 & 43 & 2.10 & 1.40 & 1.50 & 0.60 \\  & 8.8 a & 240 & 30 & 2.40 & 2.86 & 0.84 & 0.46 \\ \cline{2-7}  & - & - & - & - & Mean \(\pm\) SD & \(1.17\pm 0.31\) & \(0.53\pm 0.07\) \\ \hline \multirow{5}{*}{**Cineole**} & 4.9 a & 95 & 55 & 3.81 & 3.87 & 0.98 & 0.50 \\  & 5.0 a & 168 & 31 & 2.52 & 1.66 & 1.52 & 0.60 \\  & 5.0 a & 264 & 42 & 3.43 & 2.13 & 1.61 & 0.62 \\  & 5.1 a & 16 & 48 & 0.44 & 0.49 & 0.90 & 0.47 \\  & 5.1 a & 16 & 49 & 0.55 & 0.60 & 0.92 & 0.48 \\  & 5.1 a & 40 & 50 & 0.58 & 0.58 & 1.00 & 0.50 \\  & 5.2 a & 192 & 32 & 4.87 & 3.41 & 1.43 & 0.59 \\  & 5.2 a & 240 & 43 & 2.13 & 1.37 & 1.55 & 0.61 \\  & 8.8 a & 240 & 30 & 2.61 & 2.96 & 0.88 & 0.47 \\ \cline{2-7}  & - & - & - & - & Mean \(\pm\) SD & \(1.20\pm 0.32\) & \(0.54\pm 0.07\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: GC/MS excess data for M+2 and M+3 isotopomeres in 1,8-cineole and camphor extracted with chloroform-d and analyzed by GC/MS from spike laverned leaves at different points of time after the labelling pulse phase with \({}^{13}\)CO\({}_{2}\). SD: standard deviation. Figure 3: (**A**) Isotopologue excess values and distribution of isotopomers of cineole for selected samples in \({}^{13}\)CO\({}_{2}\) feeding experiments. All experiments are sort according to their chase time in ascending order. pu. (h): pulse time in hours. ch. (h): chase time in hours. STD: pure cineole sample. (**B**) Isotopologue excess values and distribution of isotopomers of camphor for selected samples in \({}^{13}\)CO\({}_{2}\) feeding experiments. All experiments are sort according to their chase time in ascending order.