## 3 Results and Discussion
### OPLS-DA Analysis of Soluble Compounds  
After multidimensional statistical analysis of the soluble compounds detected by both positive and negative ion modes, compounds with VIP \(>\) 1, \(p\) < 0.01, and FC \(>\) 2 or \(<\)0.5 were selected as soluble compounds with significant difference (SSD). All SSDs are listed in Table 4, consisting of 6 sugars, 10 alcohols, 16 acids, 9 amino acids, 6 purines and pyrimidines, 7 esters, and 15 other compounds. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Peak**} & \multicolumn{2}{c}{**\(m/z^{*}\)**} & \multicolumn{2}{c}{**rt(ts)**} & **Adduct** & **Description** & **Ion** & \multicolumn{2}{c}{**VIP**} & \multicolumn{2}{c}{**Fold Change**} \\  & \multicolumn{2}{c}{**Name**} & & & & & & **(IBW/FBW)** & **(FBW/IBW)** \\ \hline Sugars & M503T799 & 503.16 & 798.85 & (M-H)\({}^{-}\) & Raifinose & NEG & 1.80 & 0.43 & 2.32 \\  & M163T171 & 163.06 & 170.53 & (M+H-H\({}_{2}\)O)\({}^{*}\) & D(+)-Talose & POS & 5.37 & 4.07 & 0.25 \\  & M198T701 & 198.10 & 700.95 & (M+NH\({}_{4}\))\({}^{*}\) & D-Mannose & POS & 2.77 & 9.98 & 0.10 \\  & M341T701 & 341.11 & 701.41 & (M-H)\({}^{-}\) & Sucrose & NEG & 12.22 & 12.75 & 0.08 \\  & M179T499 & 179.06 & 498.97 & (M-H)\({}^{-}\) & D-Glucose & NEG & 14.70 & 59.36 & 0.02 \\  & M177P7559 & 179.06 & 558.83 & (M-H)\({}^{-}\) & D-Tagatose & NEG & 7.27 & 95.46 & 0.01 \\ Alcohols & M300T171 & 300.29 & 707.22 & (M+H)\({}^{*}\) & 3-ketynighanine & POS & 6.55 & 0.01 & 163.26 \\  & M302T248 & 302.30 & 248.49 & (M+H)\({}^{*}\) & Sphinganine & POS & 3.81 & 0.01 & 92.93 \\  & M137T68\_2 & 137.06 & 68.40 & (M-H)\({}^{-}\) & 2-(4- & & 5.28 & 0.02 & 57.83 \\  & M151T449 & 151.06 & 449.18 & (M-H)\({}^{-}\) & Xylitol & NEG & 1.78 & 0.03 & 38.53 \\  & M110T192 & 110.08 & 192.28 & (M+NH\({}_{4}\))\({}^{*}\) & Glycerol & POS & 1.52 & 0.08 & 13.03 \\  & M203T56 & 203.16 & 56.31 & (M+CH\({}_{3}\)COO\({}^{*}\)+2H)\({}^{*}\) & (Z)-3-Nonen-1-ol, & POS & 2.09 & 0.09 & 11.10 \\  & M183T568 & 183.09 & 568.05 & (M+H)\({}^{*}\) & D-Mannitol & POS & 1.57 & 0.25 & 4.08 \\  & M194T119 & 194.10 & 118.67 & (M+CH\({}_{3}\)CN\({}^{*}\))\({}^{*}\) & Ribitol & POS & 1.83 & 0.43 & 2.30 \\  & M40T1702 & 401.13 & 702.43 & (M+CH\({}_{3}\)COO\({}^{*}\))\({}^{*}\) & Galacintiol & NEG & 11.92 & 27.51 & 0.04 \\  & M170T200 & 170.08 & 199.94 & (M+H)\({}^{*}\) & Pyridoxine & POS & 2.17 & 13.29 & 0.08 \\ Acids & M175T554 & 175.06 & 554.46 & (M-H)\({}^{-}\) & 2-Isopropylmalic acid & NEG & 3.85 & 0.00 & 351.38 \\  & M147T753\_2 & 147.03 & 752.87 & (M-H)\({}^{-}\) & (S)-2- & NEG & 5.10 & 0.02 & 60.91 \\  & M129T356\_2 & 129.02 & 356.20 & (M-H)\({}^{-}\) & Citraconic acid & NEG & 4.01 & 0.02 & 48.55 \\  & M117T366 & 117.02 & 735.65 & (M-H)\({}^{-}\) & Succinate & NEG & 6.67 & 0.03 & 28.74 \\  & M131T579 & 131.03 & 759.02 & (M+H)\({}^{*}\) & Glutaconic acid & POS & 1.66 & 0.04 & 27.92 \\  & M37T376 & 73.03 & 735.75 & (M-H)\({}^{-}\) & Propionic acid & NEG & 1.83 & 0.04 & 27.28 \\  & M131T230 & 131.07 & 229.95 & (M-H)\({}^{-}\) & Hydrooxybenzoic & NEG & 2.91 & 0.04 & 25.38 \\  & & & & & 3.4- & & & \\ M167T73 & 167.03 & 72.78 & (M-H)\({}^{-}\) & Dihydroxyphenylacetic & NEG & 2.52 & 0.09 & 11.51 \\  & M89T424 & 89.02 & 423.59 & (M-H)\({}^{-}\) & DL-lactate & NEG & 3.06 & 0.11 & 9.42 \\  & M117T273 & 117.06 & 273.43 & (M-H)\({}^{-}\) & methylbutyric & NEG & 1.55 & 0.11 & 8.96 \\  & M178T121 & 178.05 & 120.63 & (M-H)\({}^{-}\) & Cyclohexylsulfamate & NEG & 2.60 & 0.13 & 7.60 \\  & M173T696 & 173.01 & 696.38 & (M-H\({}_{2}\)O-H)\({}^{-}\) & Isocitrate & NEG & 1.51 & 0.25 & 3.94 \\  & & & & & 3.4- & & & \\ M153T443 & 153.02 & 442.94 & (M-H)\({}^{-}\) & Dihydroxybenzoic & NEG & 1.84 & 0.29 & 3.48 \\  & & & & & & & & \\ M130T578 & 130.09 & 577.87 & (M+H)\({}^{*}\) & D-Pipecolinic acid & POS & 1.97 & 0.30 & 3.29 \\ M28T158 & 282.17 & 157.55 & (M+NH\({}_{4}\))\({}^{*}\) & Abscisic Acid (cis, & & POS & 2.08 & 0.31 & 3.23 \\  & M263T144 & 263.13 & 144.14 & (M-H)\({}^{-}\)) & (+)-Abscisic acid & NEG & 2.39 & 0.38 & 2.66 \\ \hline \hline \end{tabular}
\end{table}