## 2 Results and Discussion
### VOC Metabolites in Five Rice Varieties
\begin{table}
\begin{tabular}{c l c c c c c} \hline \hline
**RT [min]** & **Compounds** & **DAO** & **MEI** & **YE** & **HU** & **PU** \\ \hline \multicolumn{6}{c}{Shared metabolites} \\
15.29 & 1-Hexanol & \(1.72\times 10^{8}\) & 96,048,970 & \(1.13\times 10^{8}\) & 24,102,107 & 45,055,543 \\
3.78 & Fluoromethylolixrane & 36,614,040 & 23,305,508 & 44,202,528 & 28,416,649 & \(1.45\times 10^{8}\) \\
12.37 & 1-Pentanol & 37,980,623 & 30,586,851 & 25,157,322 & 6,633,422 & 7,772,666 \\
9.28 & 1-Butanol & 26,388,511 & 13,311,345 & 15,000,191 & 81,512,45 & 3,133,619 \\
1.73 & Ethly ether & 27,745,422 & 25,783,629 & 28,836,831 & 24,493,908 & 33,315,764 \\
2.36 & Acetone & 18,903,094 & 14,901,508 & 10,460,835 & 7,760,489 & 5,174,855 \\
7.15 & Hexanal & 16,299,306 & 27,805,740 & 24,085,922 & 5,099,126 & 7,709,785 \\
17.83 & Acetic acid & 15,818,963 & 36,842,037 & 11238248 & 2,015,046 & 5,899,140 \\
17.87 & 1-Octen-3-ol & 14,891,769 & 13,388,022 & 15,550,836 & 9,818,053 & 25,329,453 \\
9.7 & 1-Pentent-3-ol & 12,473,204 & 8,297,892 & 8,223,888 & 2,972,998 & 4,730,423 \\
23.32 & 2-Pentylfuran & 12,281,335 & 9,644,697 & 112,492,015 & 3,493,209 & 5,800,664 \\
18.03 & 1-Heptanol & 5,921,051 & 7,433,490 & 6,080,963 & 4,442,551 & 6,035,516 \\
42.15 & Dibbutyl phthalate & 4,606,760 & 3,567,330 & 1,983,646 & 1,391,658 & 3,006,027 \\
27.4 & Hexanoic acid & 2,799,541 & 3,840,783 & 3,387,139 & 4,241,496 & 1,079,895 \\
26.14 & 2,4-Dimethylbenzaldehyde & 4,469,583 & 8,813,779 & 10,020,634 & 3,439,346 & 3,472,676 \\
10.21 & Decamethylclopentasiloxane, & 3,331,658 & 3,697,400 & 12,829,422 & 2,784,283 & 3,643,312 \\ Dimethylsilanediol & & & & & & \\ \multicolumn{6}{c}{Important metabolites in Mei} \\
23.08 & 2,2-Dichloroethanol & 1,224,567 & 11,1523,95 & 1,224,567 & 36,892,075 & 42,942,869 \\
21.63 & 3-Methylbutanoic acid & 63,498.64 & 4,545,779 & 16,655.63 & 69,413.39 & 33,309.38 \\
23.52 & Pentaanoic acid & 1,359,020 & 1,983,710 & 1,217,325 & 1,964,045 & 779,162.5 \\
25.12 & Nonanal & & 1,160,505 & 1,628,053 & 860,797.6 & 994,269.9 & 301,766.9 \\
16.25 & 5-Ethynyldihydro-5-methyl-2(\(3H\))-furanone & 822,909.4 & 2,818,383 & 2,225,003 & 534,010.8 & 619,826.6 \\  & \multicolumn{6}{c}{Important metabolites in Hu} \\
22.96 & \(n\)-Butyl ether & 2,312,773 & 3,751,675 & 448,611 & 929,572.9 & 634,660.8 \\
4.34 & Indole & 404,411.8 & 323,469.5 & 346,924.8 & 2,304,147 & 147,699.5 \\
37.99 & 1,2,4,5-Tetramethylbenzene & 361,177.9 & 33,235.97 & 412,467.8 & 1,828,698 & 259,974.3 \\
16.95 & (Z)-Hexen-1-ol & 1,300,407 & 1,031,014 & 1,357,945 & 2,231,575 & 1,244,037 \\  & Important metabolites in Pu & & & & & \\
16.67 & 3-Isopropyl-1,1,1,7,7,7- hexamethyl- & 1,782,711 & 613,313.8 & 1,060,169 & 282,098.5 & 282,098.7 \\
19.52 & 2,4,6-Trimethyldecane & 447,896.4 & 454,443.5 & 464,899.2 & 437,090.2 & 18,992,198 \\
6.06 & 2,6-Dimethylionine- & 207,859.7 & 344,146.2 & 287,853.3 & 286,306.8 & 3,265,933 \\
17.62 & 5-Furanmethanol, & 2,878,806 & 1,420,566 & 824,133.5 & 1,205,407 & 2,184,705 \\
16.42 & 3-Octanol & 1,906,009 & 798,094.8 & 1,202,779 & 759,883.7 & 1,993,274 \\
27.74 & 2,2,4-Trimethyl-1,3-pentanediol & 1,607,821 & 1,984,047 & 977,550.7 & 827,407.3 & 1,767,177 \\  & \multicolumn{6}{c}{Important metabolites in Dao} \\
8.24 & 2-Butanone & 3,680,787 & 3,095,654 & 1,581,748 & 1,120,188 & 864,840.9 \\
14.63 & 2-Acetyl-1-pyrroline & 3,452,700 & 133,350.6 & 265,893.5 & 48,794.77 & 48,795.2 \\
21.49 & 1-Methylcycloheptanol & 3,180,146 & 1,081,452 & 1,261,950 & 638,954.6 & 1,807,368 \\  & \multicolumn{6}{c}{Important metabolites in Aromatic rice} \\
13.1 & Acetoin & 88,606,134 & 24,735,894 & 3,040,508 & 2,235,303 & 882,512.3 \\
10.16 & 2-Heptanone & 4,476,631 & 3,992,086 & 3,172,086 & 1,076,111 & 1,275,083 \\ \hline \hline \multicolumn{6}{c}{Dao stands for the Daohuaxiang 2 variety, Ye stands for the Yexiangyoulisi variety, Mei stands for the Meixiangzhan 2 variety, Hu stands for the Huanghuazhan variety and Pu stands for the Yanfeng 47 variety.} \\ \end{tabular}
\end{table}