鸳鸯茉莉花色变化过程中的生理生化特性研究

以3年生鸳鸯茉莉(Brunfelsia acuminata Benth.)5个不同花期(花蕾期、初开期、全开期、过渡期、末花期)的花瓣为试材,研究其开花过程中花瓣的色度值、类黄酮、类胡萝卜素、花色苷含量、细胞p H值以及相关酶活性的变化,并分析各指标之间的相关性。结果显示,除全开期外,其它4个时期各色度值变化不明显,初开期、全开期和过渡期,明亮参数L值逐渐增大,红绿参数a值、黄蓝参数b值和彩度C值急剧降低;类黄酮含量在过渡期最低,其它阶段无显著差异;类胡萝卜素含量变化呈上升-下降-稳定的趋势,全开期达到最高;花色苷含量则随开花进程不断下降,花蕾期最高;花蕾期、初开期、全开期的SOD活性变化不显著,过渡期时显著升高,末花期又迅速回落到最低值;POD活性不断上升,末花期为花蕾期的28.73倍;CAT活性前期变化不显著,末花期时有一定幅度的升高;花瓣色度各指标、花色苷含量、上述酶的活性、p H值等几个参数间均存在极显著相关性,但SOD活性、类胡萝卜素、类黄酮与所有参数的相关性均不显著。研究结果表明花色苷是影响鸳鸯茉莉花色变化的决定性代谢产物,POD和CAT活性是调节花色苷降解速率的主要抗氧化酶。

Study on the physiological and biochemical characteristics of Brunfelsia acuminata petals during flowering

To explain the floral chromogenic mechanism of Brunfelsia acuminata Benth., 3-year-old B. acuminata petals during different flowering stages, including unfold-petal stage (UPS), initial-flowering stage (IFS), full-flowering stage (FFS), transitional-flowering stage (TFS), and flowering-wilting stage (FWS), were used and the floral color index, flavonoid content (FC), anthocyanin content (AC), carotenoid content (CC), pH index, relative enzyme activity and their correlations were measured. Results showed the flowering color change was not obvious during the UPS-IFS and TFS-FWS, the L value (bright parameter) increased gradually, whereas the A value (red/green parameter), B value (blue/yellow parameter), and C value (chroma) reduced sharply. The flavonoid content was lowest during the TFS, and there were no significant differences among the other stages. The carotenoid content trend was increasing-decreasing-stable, and the content during the FFS was the highest. The anthocyanin content decreased continuously from the UPS. The SOD activity from the UPS to FFS changed non-significantly but increased during the TFS and rapidly dropped to the lowest level during the FWS. The POD activity increased continuously and was highest during the FWS. The CAT activity changed non-significantly, and only increased in the late flowering stage. The correlations among the floral color index, anthocyanin content, POD activity, CAT activity, and pH value were significant, but were not significant among SOD activity, carotenoid content, flavonoid content, and other indexes. Anthocyanin was the decisive metabolite of B. acuminata flower color, and the activities of POD and CAT were the main antioxidant enzymes, which were involved in the adjustment of the anthocyanin degradation rate.