凤眼果的生药学研究

Pharmacognostical study of Sterculia monosperma fruit

关键词:  凤眼果, 性状鉴别, 微性状鉴别, 显微鉴别, DNA条形码

Key words:  Sterculia monosperma fruit, morphological identification, micro-morphological identification, microscopic identification, DNA barcode

摘要:

凤眼果具有温胃、杀虫等功效,其名称和性状易与苹婆属其他物种混淆,然而其相关研究基础比较薄弱。该研究对凤眼果性状、微性状、种子横切面及粉末显微特征进行观察; 利用双向测序获取凤眼果DNA条形码序列ITS2、psbA-trnH、matK、rbcL,计算Kimura 2-Parameter(K2P)遗传距离,建立邻接系统进化树并进行聚类分析。结果表明:(1)凤眼果性状特征为外被深红色果皮,种子表面红褐色或暗栗色,质硬,内含浅黄色肥厚胚乳2片。(2)微性状特征为外种皮红褐色,极薄,质脆; 中种皮黑褐色,较厚,质硬; 内种皮浅黄色,质软。(3)显微特征为外种皮石细胞结构和排列方式、中种皮栅状细胞结构、内种皮细胞壁呈连珠状增厚、草酸钙簇晶。(4)基于ITS2序列可将凤眼果与苹婆属其他植物有效区分,matK序列可将假苹婆与苹婆属其他植物有效区分。该研究获取的凤眼果性状、微性状及显微特征数据,结合ITS2条形码序列可有效鉴别凤眼果,为其资源开发及质量标准制定提供了科学依据。

Abstract:

Sterculia monosperma fruit is the dried and mature seed of Sterculia monosperma, which belongs to genus Sterculia. In China, this plant is a widely distributed arbor with a long planting history in Lingnan area. It is mainly cultivated in Guangdong, Guangxi, Fujian, Yunnan and Taiwan of China; it is also distributed in India, Vietnam and Indonesia, mostly cultivated artificially. S. monosperma fruit has many functions like warming the stomach and killing pests, but its name and characteristics are easily confused with other plants of genus Sterculia. However, the relevant research foundation is relatively weak. Pharmacognostical study can provide reference for its resource development and quality standard formulation. This study identifies the morphological and microscopic characteristics of S. monosperma fruit, as well as the microscopic identification of seed cross-section and powder. The DNA barcode sequences ITS2, psbA-trnH, matK and rbcL of S. monosperma were obtained through bidirectional sequencing, Kimura 2-Parameter(K2P)genetic distance was calculated, and the neighbor joining tree was established for clustering analysis. The results were as follows:(1)The morphological characteristics of S. monosperma fruit included dark red fruit shell and reddish brown or dark chestnut surface. It was hard in texture, with two thick yellowish endosperms inside.(2)The micro-morphological characteristics was that the exotesta was reddish brown, extremely thin, and brittle in texture; the mesotesta was black brown, thick, and hard in texture; the endotesta coat was light yellow and soft in texture.(3)The microscopic characteristics included the structure and arrangement of the exotesta stone cell, the grid cell structure of the mesotesta, the bead thickening of the cell wall of the endotesta cells, and the calcium oxalate cluster crystals.(4)Based on the ITS2 sequence, S. monosperma fruit could be effectively distinguished from other plants in genus Sterculia, while the matK sequence could effectively distinguish S. lanceolata from other plants in genus Sterculia. This study obtained the data on the morphological characteristics, micro-morphological characteristics and microscopic characteristics of S. monosperma fruit. Combined with the ITS2 barcode sequence, S. monosperma fruit can be effectively identified, which provides a scientific reference for the development of its germplasm resources and the formulation of relevant quality standards.