Supported by Zhangzhou Nature Fund (zz2021j14); Fujian public welfare research institutes (2019r1010-3).
为明确野牡丹属(Melastoma)植物花瓣的色素成分和呈色机理，对5种野牡丹属植物的花色素成分及含量进行测定,观察花瓣表皮细胞的显微结构和分布特点，并分析花瓣pH值、可溶性糖和可溶性蛋白含量等对花色的影响。结果表明，野牡丹属植物花瓣不含叶绿素和类胡萝卜素，紫罗兰色系主要含花青素苷和黄酮类化合物，白色系主要含黄酮类化合物。野牡丹(M. candidum)和毛稔(M. sanguinrum)花瓣的花色素分布于上、下表皮，印度野牡丹(M. malabathiricum)的花色素分布于上、下表皮和栅栏组织，白花野牡丹(M. candidum f. albiflorum)和白花印度野牡丹(M. malabathricum var. alba)花瓣未见色素积累；紫罗兰色系野牡丹上表皮细胞呈圆锥形突起，白色系野牡丹上表皮细胞呈不规则的扁平状，两色系下表皮细胞均呈不规则的扁平状。野牡丹属植物花色明度(L*)随花瓣颜色加深而降低，L*与红度(a*)呈极显著负相关、与蓝度(b*)呈极显著的正相关。花瓣中花青素苷含量与其L*和b*呈显著负相关，pH值与花瓣a*呈现显著的负相关。因此，野牡丹属植物花色主要由花青素苷决定，花青素苷含量、色素分布、上表皮细胞形状等是引起花色呈现多样的主要因子。
In order to clarify the pigment composition and color mechanism of petals of Melastoma, the anthocyanins in 5 species were determined, the structure and distribution of petal epidermal cells were observed, and the influence of pH value, soluble sugar and soluble protein content on flower color was analyzed. The results showed that the petals of Melastoma had not chlorophyll and carotenoid, violet color mainly contained anthocyanin and flavonoids, and flavonoids in white color. The anthocyanins distributed in upper and lower epidermis of M. candidum and M. sanguinrum petals, and aslo in palisade tissue of M. malabathiricum, but the petals of M. candidum f. albiflorum and M. malabathricum var. alba had no pigment accumulation. The cells in upper epidermis of violet Melastoma show conical protrusions, which in white Melastoma show irregular flat shape, and those in lower epidermis of both colors show irregular flat shape. The brightness (L*) of flower color decreased with the deepening of petal color, which was negatively correlated with the redness (a*) and positively with the blueness (b*). The anthocyanin content had significantly negative correlation with L* and b*, and as well as pH and a*. Therefore, anthocyanin was the main determinant of flower color in genus Melastoma, anthocyanin content, pigment distribution and shape of upper epidermis cells were the main factors that cause color diversity.