彩叶桂叶片发育过程中叶色表型与色素成分变化

【目的】探究彩叶桂叶片发育过程中叶色表型与色素成分的关系。【方法】以彩叶桂品种‘虔南桂妃’(Osmanthus fragrans‘Qiannan Guifei’)5个发育时期(S1—S5)的叶片为研究对象，选用英国皇家园艺学会比色卡和色差仪测量其叶色表型，同时采用可见光分光光度法对5个时期的叶片进行叶绿素和类胡萝卜素的测定，利用超高效液相色谱-串联三重四级杆-飞行时间质谱(UPLC-Triple-TOF/MS)联用技术定性定量分析叶片中类黄酮成分与含量，进一步分析了叶色与各色素成分之间的相关性。【结果】随着叶片不断发育，彩叶桂叶片颜色变化大致分为两个阶段：第1个阶段由红转黄(S1—S3),第2个阶段由黄转绿(S3—S5)。叶片颜色参数明度L^*值和蓝度b^*值先增加后下降，而红a^*值和彩度C^*值则呈下降趋势。在叶片中共鉴定出了8种类黄酮，包括1种花青素(Cy3R)、3种黄酮(Ap7G、Ap7R和vicenin-2)以及4种黄酮醇(Km3R、Km7G、Km3G7R、Qu3R)。定量分析发现：叶绿素和类胡萝...

Changes of coloration and pigment compositions during leaf development of Osmanthus fragrans colour group cultivar

【Objective】 This study aimed to explore the relationship between leaf color changes and pigment composition in Osmanthus fragrans color group during the leaf development. 【Method】 Different-colored leaves of the O. fragrans color group cultivar ‘Qiannan Guifei’ were selected from five developmental stages (S1-S5) for phenotype mensuration using the Royal Horticultural Society Color Chart and colorimeter. Chlorophyll and carotenoid concentrations of the leaves were determined using visible light spectrophotometry. Flavonoids were qualitatively and quantitatively characterized using ultra-performance liquid chromatography triple-time-of-flight/mass spectrometry (UPLC-Triple-TOF/MS). The correlation between leaf color and pigment components was also analyzed. 【Result】 The results indicated that the changes in leaf color could be roughly divided into two stages in relation to the leaf development: the first stage was from red to yellow (S1-S3), and the second stage was from yellow to green (S3-S5). The color parameters L^* and b^* initially increased and then decreased, while the values of a^* and C^* decreased. Eight flavonoids were detected in the leaves of ‘Qiannan Guifei’, including one anthocyanidin (Cy3R), three flavones (Ap7G, Ap7R and vicenin-2), and four flavonols (Km3R, Km7G, Km3G7R and Qu3R). The quantitative analysis showed that chlorophyll and carotenoid concentrations were relatively low and stable during stages S1-S3, whereas the concentrations and ratios of the two pigments increased significantly during stages S3-S5. Cy3R concentration significantly decreased from stages S1 to stage S3, and it occurred in undetectable trace amounts in stages S3-S5. The concentrations of Qu3R, Km3R, Km7G and Ap7G also decreased from stage S1 to stage S5, while vicenin-2 and Km3G7R showed a continuous increase. Ap7R was stable from stage S1 to stage S3, and then it initially decreased and then increased. 【Conclusion】 The decrease of anthocyanidin (Cy3R), flavone (Ap7G) and flavonols (Qu3R, Km3R and Km7G) was critical in promoting changes in leaf color from red to yellow in ‘Qiannan Guifei’, while the increase in the ratio of chlorophylls to carotenoids resulted in the leaves changing from yellow to green.