【作者】 郑智；

【导师】 吕长平；

【作者基本信息】 湖南农业大学 ， 观赏园艺学， 2009， 硕士

【摘要】 木芙蓉（Hibiscus mutabilis）又命芙蓉、拒霜花,为锦葵科、木槿属,落叶灌木或小乔木。本研究以不同花色木芙蓉为材料运用测色法,紫外分光光度法,化学显色法,植物成分分析等方法,从花色表型测定与分析,理化因子对类黄酮呈色的影响,木芙蓉花色素的化学分析等方面对木芙蓉花色的形成进行了研究。为木芙蓉品种分类以及新的花色品种的培育奠定基础,同时,为进化生物学研究提供参考依据。本试验主要结果如下：1.使用目视测色和色差仪测色两种方法对木芙蓉3个品种的花色进行评价,经综合分析将木芙蓉花色分成红色（red group）、白色（white group）、粉色（pink group）三个色系。运用色差仪对木芙蓉的花色进行了测量。结果发现,木芙蓉不同花色品种的亮度（L^*）和红度（a^*）表现出显著的负相关关系,即随着红度的降低,花色的亮度越来越高；L^*与黄度（b^*）表现出显著的正相关关系,这说明随着黄度的提高,花色的亮度也相应地增加。2.本试验研究了温度、光照、酸碱性和金属离子对木芙蓉花色素在离体条件下呈色的影响,结果发现：①55℃以下的温度对类黄酮呈色的影响不明显,只有红色、粉色品种花青素随温度升高略有降解；②光照可以明显影响红色品种花青素的呈色,花青素在光下容易降解,使颜色变浅,且光照越强降解幅度越大；白色系品种的黄酮类化合物对光照稳定；③pH值对红色系花青素的呈色影响较大。在pH值3.8缓冲体系中花青素具有最大的吸光度,之后随着溶液pH值的升高颜色变浅、λmax红移,部分品种花青素在pH>7.0时变绿,说明花青素的结构已经被破坏；pH值对白色系品种影响不大,仅pH>7.0时产生浑浊,同时白色系品种类黄酮变黄；④Fe³⁺、Mg²⁺、Al³⁺、Ca²⁺对红色系‘牡丹红’花青素有增色作用,金属离子对白色系‘醉芙蓉’白色花瓣黄酮类化合物无明显影响。3.在本研究中,使用紫外-可见光谱对木芙蓉花瓣中存在的类胡萝卜素、黄酮类化合物和花青素三类色素进行了分析,结果发现：①黄酮类化合物的特征吸收峰在331nm和271nm附近,存在于所有的木芙蓉品种中,由于它的光吸收特性,因此大部分化合物表现为无色或者很淡的黄色；②类胡萝卜素的特征吸收峰是442nm和471nm,属于可见光区,所以大多会表现出黄色到橙黄等花色。类胡萝卜素存在于红色和粉红木芙蓉花瓣中,表现出黄色或者与其他类型花色素共同形成花色；③花青素的特征吸收峰在525和252nm附近,在525nm处的光吸收,使花青素表现出非常鲜艳的花色,花青素存在于红色系和粉色系花瓣中。4.用紫外分光光度法分别测量了木芙蓉三个品种花瓣的总黄酮、花青素和类胡萝卜素的含量。结果发现：不同色素种类和含量的差异是形成花色色系的直接原因,总黄酮、总花青素和总类胡萝卜素的含量与亮度（L^*）呈负相关关系；红色和粉红系的主要色素花青素与红度（a^*）呈显著的正相关关系,而白色系的主要色素类胡萝卜素与黄度（b^*）同样也呈显著的正相关关系。总黄酮和总花青素的含量通常与总类胡萝卜素呈现负相关,而黄酮类化合物作为花青素的前体物质,与花青的含量呈现显著的正相关关系。更多还原

【Abstract】 Hibiscus mutabilis belongs to Malvaceae,deciduous shrub or subtree.lt has a long history of cultivation in home and a broad. The research was based on the various flower color of Hibiscus mutabilis from Hu Nan. The methods of different color measurement （checked using normal eye and spectrophotometer）,observation by visible spectra,specific color reactions and chromatography were used in this dissertation. The most studies focused on the three aspects:the first was the measurement and analysis of flower color; the second the effect of Physical and chemical factors on flower coloration:the third was the phytochemistry of flower pigments of Hibiscus mutilis petal. These data is useful for planting and breeding of the Hibiscus mutabilis.The results are indicated as follows:1.The flower color of 3 Hibiscus mutabilis cultivars was checked using normal eye and spectrophotometer.Lightness（L^*） and chromatic component （a^* and b^*）of these cultivars are obtained by spectrophotometer.According to the CIELAB color coordin-ate,all cultivars were divided into three groups:red, white,and pink based on the Q cluster analysis.In the same time,the system of flower color measurement of Hibiscus mutabilis was discussed.The digitization of flower color is very important for the studies of flower color of ornamental plants. Analysis of the CIELAB color coordinate of flower color,the relationship of significant negative correlations between a* and L^*was founded.That is,from green to red of flower color,the less lightness the flower has. But the significant positive correlation between b^* and L^* was showed in white, pink groups and red groups respectively.Those results show that a^* and b^* are the important factor for lightness and flower coloration.2.The color expression of flavonoids in white cultivars is not sensitive to temperature, light,and pH value.The color expression of anthoeyanins of red and pink cultivars is stable under 55℃in methanol and sensitive to light and pH value. Anthoeyanins degradate significantly in light.The red color of anthoeyanins in some cultivars fades gradually and has a bathoehromiec shift ofλ_vis-max:as The increase of pH value in solution.some metal ions, such as Fe³⁺,Mg²⁺,Al³⁺,Ca²⁺are positive to red cultivar’mu dan hong’ .Metal ions do not affect flavonoids in cultivar’zui fu rong’,obviously. These results emphasize that anthocyanins play significant roles in red and pink cultivars of the Hibiscus mutabilis.3. The flower pigment sarevery important for flower coloration.The study by UV-visible spectra indicate that flower pigments of Hibiscus mutabilis are consist of carotenoids,anthocyanins and other flavon oids.The characteristic absorption peak of carotenoid was 440nm and 470nm,the anthoeyanin was 531nm,and the other Flavonoid was 331nm and 271nm. There is only flavone in white color flower;the red and pink flower contains anthoe-yanlns and other flavonoids.4.To understand the quantitative effect of major pigment s on flower color variation in Hibiscus mutabilis cultivars,flavornols （FL）,carotenoids （CA）, chlorophylls（CH） and anthoeyanins（AN） were extracted from the flowers and analyzed both qualitative-ly and quantitatively with UV-visible spectral.The results indicated that all of the cultivars contain flavonol,which are colorless and act as the copigment for some color groups.The anthoeyanins were responsible for flower colors of the red,and pink, its content is important for the flower coloration.The relationship of significant negative correlations between total anthoeyanins（TA）,total carotenoid （TC）, total flavonoids （TF） and L^* was founded.The significant positive correlations between TA and a^*,TC and b^*were founded respectively.The content of TC is negatively related to TF and TA,but the content of TF is positively related to TA.At last,according to the content of flower pigments,all cultivars were classified into five groups:FLgroup,containing flavonols;FL,AN group,anthocyanins and flavonols;FL,CA group flavonols and carotenoids;FL,AN,CA group, anthocyanins, flavonols and carotenoids; FL, CH, CA, group,flavonols,chlorophylls and carotenoids.The classification according to flower color and pigments is correlative and this will be benefited for cultivar classification of Hibiscus mutabilis.更多还原