# Bumblebee Pollination Enhances Yield and Flavor of Tomato in Gobi Desert Greenhouses
## 4 Discussion
### Bumblebee Pollination Improved Tomato Flavor  
Tomato fruits from bumblebee pollination had more consumer liking compounds than fruits from vibrator or PGR treatments. For most fruits, the contents of sugars and acids are the major factors in determining taste [28]. It was reported that the balance between sugar and acid contents affects tomato fruit taste, and high but balanced levels of sugar and acid \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Compounds Names**} & \multirow{2}{*}{**Formula**} & \multirow{2}{*}{**CAS**} & \multicolumn{3}{c}{**Concentration (ng g\({}^{-1}\))**} & \multirow{2}{*}{**Consumer**} \\ \cline{3-3} \cline{5-6}  & & & **Bumblebee** & & **Vibrator** & **PGR** & **Liking Effect** \\ \hline Eugenol & C\({}_{10}\)H\({}_{12}\)O\({}_{2}\) & 97-53-0 & 0.68 \(\pm\) 0.03 & 0.62 \(\pm\) 0.05 & 0.70 \(\pm\) 0.03 & Negative \\ Disulfide, dimethyl & C\({}_{2}\)H\({}_{6}\)S\({}_{2}\) & 624-92-0 & 0.19 \(\pm\) 0.03 & 0.53 \(\pm\) 0.10 & 0.08 \(\pm\) 0.00 & Negative \\ Furfural & C\({}_{5}\)H\({}_{4}\)O\({}_{2}\) & 98-01-1 & 0.04 \(\pm\) 0.002 & 0.03 \(\pm\) 0.01 & 0.03\(\pm\) 0.01 & Negative \\ Ethyl acetate & C\({}_{4}\)H\({}_{8}\)O\({}_{2}\) & 141-78-6 & n.d. & 0.08 & 0.24 & Negative \\ Dimethyl sulfide & C\({}_{2}\)H\({}_{6}\)S\({}_{2}\) & 75-18-3 & n.d. & 0.02 & 0.02 & Negative \\ \hline \end{tabular}  
* One-way ANOVAs were used to analyze the compound concentration differences of tomato fruits by different pollination methods. Data are shown as average \(\pm\) standard error and only average values are presented for compounds which detected in less than three samples. The ’n.d’ indicates not detected. The ’*’ indicates significant difference and different letters indicate significant differences among different pollination treatments based on the Duncan test at \(\alpha\) = 0.05. ’Positive’ and ’Negative’ indicate significant correlation with consumer liking scores based on consumer evaluation panels from references [28; 39; 41; 42; 43].  
\end{table} 
Table 1: _Cont._are desired by consumers [51]. [PERSON]'s study indicated that bee-pollinated tomato had more depth of flavor than wand-pollination and was more preferred in sensory pilot study, but they found no significant differences of the soluble solids and titratable acidity content in cherry tomatoes from bee and wand pollination [35]. In their study, a handheld refractometer was used to measure the soluble solid content and acid-base titration was used to measure the titratable acidity content. However, these methods are less accurate and do not detect the single compounds of sugar or organic acid in tomato, or levels of soluble solid or titratable acidity. The main sugars in mature tomato are fructose and glucose with small amounts of sucrose. The major organic acids in tomato fruits are citric acid and malic acid, of which, citric acid is the most abundant acid while malic acid is only present 1/10 the level of citric acid [52]. In our study, a much more reliable technique-HPLC-QqQ-MS/MS was used to measure sugars and acids, and results showed that bumblebee pollinated-tomato fruits had much higher amount of fructose and glucose, but lower amount of sucrose and acids. Similar results were found in melon: melons from bumblebee or honeybee pollination had higher content of glucose and fructose, but lower content of sucrose than melons from PGR treatment [48]. The content of both sugars and acids in tomato are highly dependent on the fruit developmental stage and ripeness [31]. During the tomato fruit ripening stage, the fructose and glucose increase while the sucrose content declines [39]. Organic acids in tomato fruits can help to enhance the feeling of sweetness [42]. At the early stage of fruit development, the content of organic acids in tomatoes increased with time and decreased at the late stage of fruit development [31; 53]. In our previous study, we found that fruit development could be accelerated by bumblebee pollination through adequate fertilization [54].