Influences of bagging on pigmentation development of plum and analysis of factors related with anthocyanin synthesis

Experiment was conducted with Dashizaosheng plum cultivar (Prunus salicina Lindl.) to probe the effects of different color bags on pigmentation and anthocyanin content. Factors related with anthocyanin synthesis including total sugar, organic acid, enzyme activities of PAL (phenylalanine ammonia-Iyase) and UFGT (UDP-glucose:anthocyanidin 3-O-glucosyltransferase) were analyzed. The results showed that: significant correlation was found between light transmission percentage of bags and fruit pigmentation; and the higher light-transmitted was the bag, the deeper red was fruit peel and the higher a* value. Except for white bag, bagging with other color bags brought significant effects on fruit pigmentation as compared to control (non-bagged), though no different effects found between using red bag and yellow bag. The most significant effect of bagging on fruit pigmentation was found when using black bag (no light transmitted). Anthocyanin content in peels of mature fruit was positively relevant to light intensity, especially when wavelength longer than 580 nm(r0.99*). Sugar and organic acid content in fruit flesh were not affected by bagging, while the organic acid content in peel, not the sugar content in peel of mature fruit was positively relevant to anthocyanin content(r=0.981 5*). Moreover, the activities of PAL and UFGT were also positively relevant to anthocyanin content, with a 0.961 3* and 0.936 5* correlation coefficient respectively.