Postgraduate Education Reform and Quality Improvement Project of Henan Province, Grant No. YJS2021JD17 and the Henan Provincial Department of Science and Technology Research Project, Grant No. 202102110078.
【Objective】 The study not only explored the mechanism of flower colour formation in rose but also provided theoretical references and receptor cultivars for flower colour breeding, by the quantitative evaluation and correlation analysis of the physicochemical factors affecting the coloration of rose petals. There was of great significance for exploring the mechanism of flower color formation and germplasm innovation. 【Methods】 8 cultivars of rose with different flower colors were used as experimental materials to measure and compare the physicochemical indexes such as petal color parameter, pH value of petal cell, metal ions content, total anthocyanin content, total flavonoids content, and total chlorophyll content, etc., and the anthocyanin components qualitatively and quantitatively were analyzed. 【Results】 Results showed: (1) There were significant differences between the physicochemical factors of different flower colors of roses, among which the factors such as pH value of petal cell, Fe3+, Ca2+, Al3+ content, and the total anthocyanin content and total flavonoids content were closely related to the formation of petal color, but the changes in the content of total flavonoids and total anthocyanin played direct roles, and the factors such as metal ions and pH value of petal cell affected the flower color by changing the structure of the anthocyanidin. (2) The anthocyanin components contained in the petals of the 8 roses were mainly compounds formed by the glycosidation of cyanidin and pelargonidin; and the flavonoids were mainly derivatives such as glycosylated or acylated of quercetin and kaempferol. Among them, cyanidin-3,5-diglucoside dominated in the roses and mainly regulated the formation of purplish-red flowers; followed by pelargonidin-3,5-diglucoside, which mainly regulated the formation of orange and red flowers. Yellow flowers contained very little anthocyanin and were mainly regulated by carotenoids; orange flowers were dually regulated by both anthocyanin and carotenoids; and white flowers contained almost no anthocyanin. Rutin was abundant in all 8 rose cultivars, but there was no significant correlation with petal formation. (3) The cluster analysis of the anthocyanin components in 8 rose petals revealed that the pink-purple cultivar ''Lavender Flower Circus'' was always clustered in a separate group with high rutin content and small anthocyanin content. 【Conclusion】 It was shown that the type and content of anthocyanins directly affected the flower colour of rose, while flavonoids assisted in the formation of anthocyanin, and factors such as pH value of petal cell, Fe3+, Ca2+ and Al3+ content indirectly affected the flower colour. Among the 8 selected cultivars of rose, the pink-purple cultivar ''Lavender Flower Circus'' was the most suitable recipient cultivar for flower colour improvement due to its excellent anthocyanin composition and high pH value of petal cell.