## 3 Results and Discussion
### Association Analysis and Discussion  
The above results indicate that the differences in the types and contents of aroma substances may be the main reasons for the differences in the suitability of cultivars, but do these aroma substances affect human sensory evaluation? This suggests the necessity of further analysis of their association, so [PERSON]'s correlation analysis was used to analyze the relationships among aroma substance data, sensory data, and electronic nose data. Figure 4 and Table S10 show the correlations among 47 significantly different aroma substance data, 16 electronic nose sensor responses values, and consumer acceptance and expert review scores. Among volatile terpen, Cosmee, Linalool oxide pyranoside, \(\alpha\)-Cubebene, \(\beta\)-Caryophyllen, \(\alpha\)-Muurolene, \(\delta\)-Cadinene, \(\alpha\)-Cadinol, and 16 electronic nose sensors (LY type sensors: LY2/AA, LY2g/CTL, LY2g/CT, LY2/G, and LY2/GH; T type: TA/2, T70/2, T40/2, and T30/1; \(p\) type: P30/2, P10/2, PA/2, P30/1, P40/2, P40/1, and P10/1) all had weak correlation (0.3 \(<\) /correlation coefficient/ \(<\) 0.5), no correlation (/correlation coefficient/ \(<\) 0.3), or no strong correlation (/correlation coefficient/ \(<\) 0.7) with human sensory data (expert review data and consumer acceptance data). This indicates that these seven terpen are likely to have little effect on the human sensory perception of samples from different cultivars. \(\alpha\)-Terpineol, Linalyl formate, Geraniol, \(\alpha\)-Farnesene, (E)-Nerolidol, (E)-Furan linalool oxide, Linalool oxide pyranoside, and T-Muurolol had a weak correlation (/correlation coefficient/ \(<\) 0.5) with LY type sensors, but a moderately strong correlation (0.5 \(<\) /correlation coefficient/ \(<\) 0.7) or strong correlation (0.7 \(<\) /correlation coefficient/ \(<\) 1) with almost all T type and \(p\) type sensors. It is worth noting that \(\alpha\)-Terpineol, Geraniol, (E)-Nerolidol, and \(\alpha\)-Farnesene showed weak correlation (0.3 \(<\) /correlation coefficient/ \(<\) 0.5) or no correlation (0 \(<\) /correlation coefficient/ \(<\) 0.3) with human sensory data. This indicated that these four substances did not contribute to the sensory differences in samples of different suitability. However, \(\beta\)-Ocimene, (Z)-Furan linalool oxide, linalool, (3E)-4,8-Dimethyl-1,3,7-nonatriene, (E)-Pyranoid linalool oxide, \(\gamma\)-Elemene, Humulene,(E)-\(\beta\)-Famesene, and (Z,E)-\(\alpha\)-Farnesene not only had a strong correlation with the electronic nose array, but also significantly affected the sensory score level, suggesting that they may have contributed to the sensory differences in samples from cultivars of different suitability. As metabolites present widely in a variety of plants, terpenes are not only the constituents of the floral fragrance released by plants, but also play a role in plant defense under biotic and abiotic stress [27; 28]. In tea leaves, \(\alpha\)-Farnesene and Ocimene have been found to be synthesized de novo in tea leaves treated with jasmonic acid and mechanical damage (JAMD) and pass between tea plants to initiate volatile defense mechanisms of undamaged tea plants [29]. In another report, CsOCS was mentioned as a key synthase to promote the de novo synthesis of \(\beta\)-ocimene in oolong tea processing, which is one of the important defense signals of the tea plant against adversity [30]. These reports suggested that although some of the aforementioned terpene substances (such as \(\alpha\)-Farnesene, etc.) did not contribute to human sensory perception, they may be involved in the tea tree defense signaling network in response to adverse processes (mechanical damage and low temperature processes) and indirectly affect the formation of other aroma components, and so are some of the substances that contribute to sensory formation (such as \(\beta\)-Ocimene, etc.). This may be the main reason why these terpenes caused the sensory aroma differences in samples of different suitability.