## 3 Results  
### The VOC Profile in the Headspace of K. parvirlora Rhizomes and Leaves  
Using the HS-SPME-GC-TOF-MS-based metabolomics approach, a total of 395 and 426 mass spectra peaks were observed on the VOC profiles of _K. parvirlora_ samples from the growth room and field conditions, respectively. The obtained MS peaks were provisionally identified by following the methods from [PERSON] et al. [71]. The interpretations of those spectral matrices were conducted by comparing the retention index of each peak to reference spectra from well-reported libraries [85; 86; 87; 88]. Based on the \(>\)95% matching degree of similarity, a total of 85 detected peaks were assigned as putatively annotated compounds out of 395 detected mass spectra in the growth room samples. On the other hand, 100 putative peaks were identified out of 426 matrices in the field samples. The names of the annotated compounds from the samples are listed in Supplementary Tables S1 and S2. The proportion of the main organic compounds was calculated based on the molecular formula of each annotated peak, and their chemical classes were determined. The results showed that the main classes of organic compounds in the HS samples of _K. parvirlora_ were classified into 5 groups according to their chemical properties: monoterponoids, sesquiterpenoids, oxygenates, and other hydrocarbons (Figure 2). A group of unknown compounds was exclusively present in the growth room samples and constituted the smallest fraction. The terpenes occupied the largest proportion in all samples from the two growth conditions. Sesquiterpenoids constituted the largest proportion in rhizome samples, followed by monoterponoids, oxygenates, and hydrocarbons. On the other hand, monoterponoids were the largest group in leaf samples, followed by sesquiterpenoids, oxygenates, and hydrocarbons.  
Figure 2: Relative content of identified classes of organic compounds in the headspace (HS) samples of _K. parvirlora_ rhizomes and leaves from growth room and field conditions. Different lowercase letters in the same volatile categories indicate significant differences at the \(p\) < 0.05 level.  
A Venn diagram was illustrated to visualize the qualitative differences in VOCs between tissues and growth conditions (Figure 3). The number of volatile compounds in the leaf and rhizome samples from the growth room were 78 and 75, respectively, and shared a total of 68 VOCs. Likewise, the leaves and rhizomes from the field contained 98 and 96 VOCs, and a total of 94 were common in both tissues. Among these compounds, 40 volatile components were common between tissues and growth conditions, and are separately listed in Table S3. It is worth noting that 2, 4, 7, and 10 compounds were detected exclusively from the Field_Leaves, Field_Rhizomes, GR_ Leaves, and GR_ Rhizomes samples, respectively. The identities of these compounds are also listed in Figure 3.  
These results indicate that there are significant differences in the contents of volatile compounds in the tissues of the plants grown in different conditions. The 40 compounds commonly identified in both growth conditions and tissues were considered as important compounds which can be used as candidate reference or marker compounds for _K. parriflora_.