## 2 Results
### Among-Organ Differences of VOC Emission
The first principal component displays positive loadings for lavandulol (0.246), 1,7-Octadien-3-ol (0.246), nerol (0.246) and geraniol (0.246). The second principal component was highly correlated to citronell and eicosane, with negative loadings of \(-\)0.296 and \(-\)0.295, respectively. The two compounds that had the highest relevance to the three principal components were trans-2-hexenal (\(-\)0.369) and leaf alcohol (\(-\)0.410). The variance explained by each compound is indicated in parentheses. Only compounds with a loading \(\geq\) 10.231 in at least one principal component are present. According to PCA of the VOCs in the stamen, petal, calyx, pistil, and pedel, the components were clearly separated, with PC1 and PC2 accounting for 66.4% of the total variance (Figure 8). PC1 accounted for 42.9% of the total compounds and represents the difference in the VOCs of the stamen from those of the other parts. Linalool made a large contribution to the positive direction of PC2, which accounted for 23.5% of the total variance, and was the main volatile component detected in pistil \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Organs** & **P1** & **P2** & **P3** & **P4** & **P5** \\ \hline P1 & 0 & & & & \\ P2 & 0.8827 & 0 & & & \\ P3 & 0.9943 & 0.9676 & 0 & & \\ P4 & 0.9843 & 0.9561 & 0.7764 & 0 & \\ P5 & 0.9889 & 0.9719 & 0.7608 & 0.4084 & 0 \\ \hline \hline \end{tabular} Note: P1, stamen; P2, petal; P3, calyx; P4, pistil; P5, pedel.  
\end{table} 
Table 4: Bray—Curtis dissimilarity index among five floral organs in _L. caudata_. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**ID** & **PC1 (42.9\%)** & **PC2 (23.5\%)** & **PC3 (12.4\%)** \\ \hline Hexanal & \(-\)0.106 & \(-\)0.232 & \(-\)0.165 \\ _trans_-2-Hexenal & \(-\)0.069 & \(-\)0.010 & \(-\)0.369 \\ (Z)-2-methylbutanal oxime & 0.107 & \(-\)0.258 & 0.052 \\ Leaf alcohol & \(-\)0.090 & \(-\)0.010 & \(-\)0.410 \\ trans-2-Hexen-1-ol & \(-\)0.070 & \(-\)0.010 & \(-\)0.370 \\
2-Heptanol & 0.244 & 0.000 & \(-\)0.045 \\ D-Limonene & 0.245 & 0.002 & \(-\)0.050 \\ Benzeneacetaldehyde & \(-\)0.048 & \(-\)0.293 & 0.176 \\
2-Nonanone & 0.245 & 0.000 & \(-\)0.054 \\
1-Nonen-4-ol & \(-\)0.051 & \(-\)0.271 & 0.167 \\
2-Nonanol & 0.245 & 0.000 & \(-\)0.052 \\ Citronellal & \(-\)0.048 & \(-\)0.296 & 0.175 \\ Isopleugol & 0.244 & \(-\)0.002 & \(-\)0.052 \\ Lavandulol & 0.246 & \(-\)0.022 & \(-\)0.040 \\
1,7-Octadien-3-ol, 2,6-dimethyl- & 0.246 & \(-\)0.013 & \(-\)0.041 \\ r-Cyclogenariol & 0.245 & \(-\)0.001 & \(-\)0.053 \\ Nerol & 0.246 & 0.003 & \(-\)0.047 \\ Geraniol & 0.246 & \(-\)0.004 & \(-\)0.043 \\ _p_-Anisaldehyde & \(-\)0.051 & \(-\)0.294 & 0.179 \\ (E)-Citral & 0.114 & \(-\)0.256 & 0.121 \\
2-Undecanol & 0.236 & \(-\)0.003 & \(-\)0.064 \\ Methylgeranate & 0.245 & \(-\)0.014 & \(-\)0.040 \\ Hexadecane & 0.033 & 0.197 & 0.274 \\ Diethyl phthalate & 0.019 & 0.238 & 0.258 \\ Octadecane & 0.078 & 0.215 & 0.247 \\ Eicosane & \(-\)0.049 & \(-\)0.295 & 0.178 \\ Dibutyl phthalate & 0.106 & 0.275 & 0.097 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Principal component loading for the three principal compounds. and citronellol made high contributions to the negative direction of PC2 and had a positive correlation with petals. The distribution of flower fragrance released from different tissues was inconsistent and no aggregation was observed.