关键词: 牡丹, 花青素, 类黄酮, 花色

Abstract:

【Objective】Tree peony (Paeonia suffruticosa), one of the famous traditional flowers in China, is rich in flower colors and varieties. The composition content and structure of anthocyanins and flavonoids in different color cultivars and these dynamic changes at different blooming stages were studied, in order to lay a foundation for further investigation of the floral pigment mechanism and molecular breeding of tree peony.【Method】 Five different color cultivars of tree peony were chosen as materials. Anthocyanins and flavonoids in those petals of flowers at four different blooming stages, such as bud stage (S1), initial blooming stage (S2), blooming stage (S3) and wither stage (S4), were determined by high-performance liquid chromatography (HPLC) and mass spectrometric (LC-MS) detectors. Then, the difference of anthocyanins and flavonoids among these five cultivars was analyzed, and the regulation of changing density was summarized.【Result】In total, 6 anthocyanins and 12 flavonoids were described. However, the compounds were distributed different among different cultivars. The purple cultivar, Luoyanghong, had four anthocyanins, and the white cultivar of Baixuetai had no anthocyanin. Among the 12 flavonoids, the relative contents of apigenin-5-glucoside (7.18%-58.46%), apigenin hexo-glucoside (1.44%-43.72%) and kaempferol-3,7-glucoside (2.83%-43.44%) were higher than other compounds. In addition, the significant changes were observed among the five cultivars. During the blooming periods, the total anthocyanin content were constantly accumulated and dramatically increased at S3, then reached the highest at S4. However, the total content of flavonoids was increased firstly and then decreased. It should be noted that the variation trend of different varieties was obviously different. The flavonoids contents of Luoyanghong showed the highest value at S4 ((752.93±48.10) μg∙g^-1 FW), and Zhaofen showed the highest value at S3 ((603.81±6.30) μg∙g^-1 FW). Baixueta reached the highest value ((673.45±9.96) μg∙g^-1 FW) at S2. But the other two cultivars, Yingrihong and Fenhe, reached the highest flavonoids content value at S1, with (525.88±22.38) μg∙g^-1 FW and (740.56±16.08) μg∙g^-1 FW, respectively.【Conclusion】The anthocyanins and flavonoids content were significantly different among different color cultivars. The purple cultivar always showed higher anthocyanins contents than other varieties. And the white cultivar almost did not detect any anthocyanin, relatively. What’s more, the anthocyanins were constantly accumulated during flower blooming stage, meanwhile, the flavonoids were increased first and then gradually degraded after flower opening.

Key words: Tree peony, anthocyanins, flavonoids, floral color