Abstract:

In order to study the effect of bagging on anthocyanin metabolism in different micro- environment from different canopy types，we bagged the‘Moldova’grape of pergola and vertical trellis system to represent the horizontal and vertical canopy. Temperature and relative humidity around the clusters of the two canopy types were recorded from berry expansion stage. Grape berries were picked from veraison to maturity stage to determine the component and content of individual anthocyanin in fruit skin by HPLC–MS；additionally，the enzymes activity and their gene relative expression were measured，and the grape quality of different canopy types were compared. The results showed that horizontal canopy decreased the ratio of high temperature and humidity fluctuation around the cluster compared to the vertical canopy in 2015 and 2016. The content of reducing sugar was increased by 18.33% and 15.41% and the acid was decreased compared to the vertical canopy for two consecutive years. In 2015，the content of tannin and anthocyanin of bagged fruit under horizontal canopy was increased by 22.32% and 35.29% compared to the vertical canopy，and the red chrom of fruit skin increased apparently；in contrast，the content of total phenols，flavanols and flavonoids decreased by 10.72%，10.97% and 45.04%，respectively，in 2016. At 77 days after blossom，the bagged fruit under pergola showed a higher content of individual anthocyanin；however，the bagged fruit of vertical trellis systems showed compensatory increase at 91 days after blossom. Analysis of individual anthocyanin indicated that they both have 21 individual anthocyanin and the diglucosidation，methylation and total modification of bagged fruit under pergola were higher than under vertical trellis system. From 63 to 105 days，the relative expression of the genes VvUFGT，VvLDOX，Vv5GT，VvPPO in anthocyanin metabolic pathway showed the same trend except VvOMT，but their enzyme activities showed difference. Thus it can be seen，the horizontal canopy can decrease the temperature and humidity of the micro-environment around grape，increase the quality of fruit and the degree of modification of individual anthocyanin，but the content of individual anthocyanin was decreased，at the same time，the relative expression and the activity of enzyme were changed.

Key words: grape, canopy type, bagging, anthocyanin