## 3 Results
### Effect of Covering Purslane on the Quality of the Grape Berries  
There were minor differences in the total concentrations of anthocyanins, flavonoids, and flavanols between the treatment and the control, as shown in Table 3. Covering purslane decreased the concentration of the total flavonoids by 4.5% and 1.7% in the year 2018 and the year of 2019. This phenomenon was mainly due to the covering purslane reducing the concentration of flavanols, but the effect was not significant between the treatment and the control. In the year 2018, grape berries covering purslane treatment had higher flavonol and anthocyanin concentrations than the berries of clean tillage, while the difference in anthocyanins was not significant. In the year 2019, the concentrations of anthocyanin and flavonol in grape berries had the same trend as in the year 2018. Compared to the year 2018, the total concentration of flavonoids composition increased by 3.2% after covering purslane in the year 2019. Flavonols were positively related to sunlight and protected berries from UV damage [44], and the authors speculated that covering purslane inhabited the vigor and decreased the leaf area, which led to an increase in the reflected light in the fruit zone and further increased the concentration of flavonoids. Another reason could be that clean tillage had a higher temperature and PAR, which led to excessive induction: for flavonoids [45]. The concentration of flavonoids in the grape berries decreased with the increase of light, which could well explain the higher levels of flavonoids in the year 2019 than in the year 2018. The concentration of anthocyanin was negatively related to temperature, and to a certain extent, low temperature is conducive to the accumulation of anthocyanins [46]. The concentration of different flavonoids, including anthocyanins, flavonoids, and flavanols were shown in Figure 4. Covering purslane did not affect the anthocyanin composition, including the non-acylated (Glu), acetylated (Ace) and coumarinylated (Cou) anthocyanins in 'Cabernet Sauvignon' grape berry skins significantly in both of the two years. In the year 2018, there were fewer glucoside from flavonoids (Glu), glucuronide form flavonoids (Gluc), 3\({}^{\prime}\)-hydroxylated flavonoids (F3H) in berries by clean tillage than those by covering purslane. Compared to clean tillage, there was no significant difference in galactosidic flavonoids (Gal) and 3\({}^{\prime}\)5\({}^{\prime}\)-hydroxylated flavonoids (F3\({}^{\prime}\)5\({}^{\prime}\)H) by covering purslane, as shown in Figure 4b. Compared to clean tillage, the berries by covering purslane had a lower concentration of seed flavanols and the free monomers. In the year 2019, compared to clean tillage, grape berries covering purslane had no significant difference in anthocyanin types, flavonol types, and flavonol types except for reducing the concentration of 3-hydroxylated flavonoids (F3H), as shown in Figure 4d-f. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Years**} & \multirow{2}{*}{**Treatments**} & \multicolumn{3}{c}{**Concentration (mg/Kg FW)**} \\ \cline{3-5}  & & **Anthocyanins** & **Flavonols** & **Flavanols** \\ \hline \multirow{4}{*}{2018} & CK & 665.79 \(\pm\) 4.68 & 30.45 \(\pm\) 0.74 & 7149.12 \(\pm\) 116.33 \\  & CP & 681.78 \(\pm\) 22.47 & 34.12 \(\pm\) 0.20 & 6595.01 \(\pm\) 259.35 \\  & Sig. & ns & * & ns \\ \cline{1-1}  & CK & 1033.00 \(\pm\) 18.66 & 63.08 \(\pm\) 8.87 & 6599.76 \(\pm\) 60.33 \\
2019 & CP & 1061.54 \(\pm\) 76.22 & 75.24 \(\pm\) 1.16 & 6452.28 \(\pm\) 102.71 \\  & Sig. & ns & * & ns \\ \hline \hline \end{tabular} Values are reported as means \(\pm\) SD of three biological replicates. Sig., significance. * indicates there are significant differences between treatments (\(p<\) 0.05, [PERSON]’s multiple range test) of ‘Cabernet Sauvignon’ (\(p<\) 0.05, \(t\)-test), ns, not significant. CK: clean tillage; CP: covering purslane.  
\end{table} 
Table 3: Effect of covering purslane on the flavonoid compounds of ‘Cabernet Sauvignon’ grapes.