## 3 Results
### Volatile Profiles  
In total, 83 kinds of volatiles were determined by GC-MS/MS in grapes, including phenylpropanol/benzenoid derivatives; terpenoids; fatty acid derivatives, such as alcohols, aldehydes and esters; and so on. Table S2 numbers these compounds and lists their retention time and structures, while contents can be seen in Table S3. The 83 volatiles are clustered and shown in Figure S2. As depicted, TS samples from S3 to S5 were clustered to US samples at S4 and S5, whereas the remainder were clustered. Examining the outcome in Table S3, (E)-2-hexenal was the most abundant composition in the samples, followed by 2,5-dimethylbenzaldehyde and hexanal. Undecane and indole were separately detected in US at S2 and in TS at S4, whereas \(\alpha\)-terpineol, phytol and juneol existed only in US at S1. Furthermore, 3-methylpentane, \(\beta\)-myrcene, dihydrocavelo, styrene, (E,Z)-2,6-nonadien and azulene could only be detected in TS, while naphthalene and coumaran were unique to US. The majority of those differential volatiles were fatty acid derivatives and terpenoids. The time-accumulating patterns of volatiles from S1 to S5 in both TS and US grapes were determined and the top 25 positively and negatively correlated compounds are listed in Figure 1A. A minority of accumulated volatiles in TS and US were classified into fatty acid and phenylpropanol/benzenoid derivatives. In TS, (E,Z)-2,6-nonadien was absent in primary stages but gradually increased in the following periods. 4,6-Dimethyldodecane, 1-hexanol and 2,4-di-tert-butylphenol increased almost three-fold, six-fold and two-fold, respectively, from S1 to S5 in US. However, the majority of compounds were gradually reduced during fruit ripening. The same decline patterns were exhibited by 13 volatiles in both US and TS; 7 of these were terpenoids, and (E)-2-hexen \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Site** & **Period** & **Fructose** & **Glucose** & **Malic Acid** & **Tartaric Acid** & **Citric Acid** \\ \hline \multirow{5}{*}{US} & S1 & 2.52 \(\pm\) 0.27 d* & 12.88 \(\pm\) 3.75 c & 21.58 \(\pm\) 1.53 a & 18.28 \(\pm\) 1.68 a & 1.41 \(\pm\) 0.21 a \\  & S2 & 27.68 \(\pm\) 1.86 c & 37.05 \(\pm\) 2.87 b & 4.51 \(\pm\) 0.51 c & 10.49 \(\pm\) 0.75 bc & ND \\  & S3 & 53.19 \(\pm\) 3.64 a & 59.36 \(\pm\) 5.85 a & 2.52 \(\pm\) 0.22 de & 6.53 \(\pm\) 0.30 e & ND \\  & S4 & 56.41 \(\pm\) 6.28 a & 62.36 \(\pm\) 6.90 a & 1.65 \(\pm\) 0.22 e & 6.26 \(\pm\) 0.32 e & ND \\  & S5 & 53.60 \(\pm\) 2.62 a & 58.49 \(\pm\) 4.74 a & 2.06 \(\pm\) 0.31 e & 6.11 \(\pm\) 0.14 e & ND \\  & S1 & 27.94 \(\pm\) 1.23 c & 36.86 \(\pm\) 0.35 b & 6.22 \(\pm\) 0.49 b & 11.48 \(\pm\) 1.47 b & 0.51 \(\pm\) 0.07 b \\  & S2 & 39.66 \(\pm\) 3.43 b & 50.49 \(\pm\) 4.46 b & 3.70 \(\pm\) 0.33 cd & 8.95 \(\pm\) 0.35 cd & ND \\ TS & S3 & 49.45 \(\pm\) 3.47 ab & 51.49 \(\pm\) 7.80 ab & 2.44 \(\pm\) 0.44 de & 6.59 \(\pm\) 0.52 e & ND \\  & S4 & 53.03 \(\pm\) 2.98 a & 61.93 \(\pm\) 5.33 a & 1.91 \(\pm\) 0.15 e & 6.69 \(\pm\) 0.39 e & ND \\  & S5 & 59.44 \(\pm\) 7.28 a & 65.06 \(\pm\) 6.53 a & 2.03 \(\pm\) 0.09 e & 6.34 \(\pm\) 0.59 e & ND \\ \hline \hline \end{tabular}
* Different letters stand for significantly differences in each column (\(p<0.05\)). FW: fresh weight; S: stage; ND: none detected.  
\end{table} 
Table 1: The saccharide and organic acid contents (mg.g\({}^{-1}\) FW) in grape berries during the five developmental stages in Urumqi (US) and Turpan (TS). during fruit ripening, 3-hydroxy-4-methoxybenzonitrile was constantly accumulated in TS but gradually reduced in US. The varying levels of volatiles growing in different regions might contribute to the variations in grape flavors. Principal component analysis (PCA) was also conducted. As exhibited in Figure 1B, PC1, PC2 and PC3 separately explained the variations of 84.1%, 5.8% and 3.8%, respectively, totaling 93.7%. (E)-2-hexenal ranked first in PC1 as absolute coefficient value 0.982. 1-Hexanol held the highest coefficient value 0.865 in PC2, while the coefficient value of 2,5-dimethylbenzaldehyde was 0.621 in PC3.