基于红外光谱结合化学计量学的青叶胆及其近缘种亲缘关系研究

目的 傅里叶变换红外光谱（fourier transform infrared spectroscopy，FTIR）结合化学计量学分析青叶胆及其同属近缘种的亲缘关系，为青叶胆药用植物资源的开发利用提供理论依据。方法 采集青叶胆及近缘种共39份样品的红外光谱信息，对光谱数据进行自动基线校正、自动平滑、纵坐标归一化、二阶求导等预处理，结合化学计量学分析光谱数据。结果 青叶胆及其近缘种红外光谱主要吸收区域为900~400、1 310~900、1 500~1 310、1 800~1 500、2 800~3 000、3 000~3 500 cm^-1附近。二阶导数图谱在400~1 000 cm^-1指纹区吸收峰差异明显，物种之间吸收峰的峰数、峰强、峰形差异较大。对预处理后的红外光谱数据进行主成分分析（PCA）以及偏最小二乘判别分析（PLS-DA）发现，6种獐牙菜的PCA分析优于PLS-DA分析，系统聚类分析表明青叶胆与圈纹獐牙菜、显脉獐牙菜亲缘关系较近。结论 FTIR结合化学计量学方法，能够快速鉴别不同种类獐牙菜属植物，明确青叶胆及其近缘种之间的亲缘关系，为獐牙菜属植物亲缘关系研究提供一种快速、有效的方法。

Study on genetic relationship of Swertia mileensis and its related species based on infrared spectroscopy combined with chemometrics

Objective Genetic reationships betwen Swertia mileensis and its relatives have been researched using Fourier transform infrared (FTIR) spectroscopy combined with chemometrics methods in order to provide a theoretical basis for the development and utilization of medicinal plant resources of genus Swertia. Methods Infrared spectrum information of Swertia mileensis, Swertia cincta, Halenia elliptica, Swertiaion nervosa, Swertia punicea, and Swertia binchuanennsis was collected and used in this study. Original infrared spectra data were pretreated by these methods including automatic baseline correction, automatic smoothing, ordinate normalization, multiplicative scatter correction and second derivative, and analyzed by principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA). Results Absorption area of relationship between Swertia mileensis and its relatives ranged from 900-400 cm^-1, 1 310-900 cm^-1, 1 500-1 310 cm^-1, 1 800-1 500 cm^-1, 2 800-3 000 cm^-1, and 3 000-3 500 cm^-1. Absorption peaks of the second derivative of fingerprint region in 400 to 1 000 cm^-1 were distinct, and the absorption peaks as well as peak numbers, intensities and patterns among species were quite different. Analysis of preprocessed IR data showed that PCA analysis of six Swertia species was superior to PLS-DA analysis. The results of HCA analysis showed that Swertia mileensis was closely related to Swertia cincta and Swertia nervosa. Conclusion FTIR spectroscopy combined with chemometrics method could discriminate different species of genus Swertia and display the closely genetic relationship of Swertia mileensis and its relatives, furthermore, this research would provide a fast and effective method for studying genetic relationship of genus Swertia.