| Abstrakt: |
Wild relatives play a very important role in enriching germplasm resources and improving the quality and yield of cultivated species. In this paper, the genetic relationship between Panax notoginseng and its wild relatives has been investigated by using Fourier transform infrared (FTIR) spectroscopy in order to provide theoretical bases in the variety improvement of P. notoginseng as well as the development and utilization of germplasm resources. The FTIR spectra of P. notoginseng and its wild relatives (P. japonicus var. major, P. stipuleanatus, P. vietnamensis, P. japonicus var. bipinnatifidus) as well as Panax notoginsenosides were collected. The original infrared spectra of P. notoginseng and its wild relatives were pretreated by automatic baseline correction, smoothing, ordinate normalization and second derivative. The genetic relationship between P. notoginseng and its wild relatives has been studied together with the aid of principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA). By comparing the infrared spectra of P. notoginseng with that of panax notoginsenosides, some common peaks such as 3 400, 2 930, 1 635, 1 385, 1 075 and 927 cm-1 has been found. It showed that the peak heights of P. notoginseng samples may relate with the content of panax notoginsenosides. The original infrared spectra of P. notoginseng are similar to its wild relatives and the absorption peaks of the functional groups of C—H, CO, O—H, C—N and C—O were presented. There were some differences in the fingerprint region (1 800～500 cm-1) of the second derivative spectra of these five species samples. The characteristic absorption peaks such as 1 385 and 784 cm-1 has an obviously differentiation. Then the fingerprint region of second derivative spectra is subjected to be analyzed by PCA and PLS-DA. By comparing the 3D score plots of these two methods, the classification result of PLS-DA is significantly better than PCA. In addition, the result of HCA which based on the six principal components of PLS-DA has shown that P. japonicus var. major and P. vienamensis have close relationship with P. notoginseng while P. stipuleanatus and P. japonicus var. bipinnatifidus are far from P. notoginseng. The use of Fourier transform infrared spectroscopy combined with chemometrics methods could effectively investigate the genetic relationship between P. notoginseng and its wild relatives. Furthermore, it could provide reference for the research of medicinal plants. |
